Showing papers in "Procedia environmental sciences in 2011"

Nodular diagnosis for ecological engineering of the symbiotic nitrogen fixation with legumes

Abstract: As a major contributor to the reduced nitrogen pool in the biosphere, symbiotic nitrogen fixation by legumes plays a critical role in a sustainable production system. However this legume contribution varies with the physico-chemical and biological conditions of the nodulated-root rhizosphere. In order to assess the abiotic and biotic constrains that might limit this symbiosis at the agroecosystem level, a nodular diagnosis is proposed with common bean as a model grain-legume, and a major source of plant proteins for world human nutrition. The engineering of the legume symbiosis is addressed by participatory assessment of bean recombinant inbred lines contrasting for their efficiency in use of phosphorous for symbiotic nitrogen fixation. With this methodology, in field-sites chosen with farmers of an area of cereal-cropping in the Mediterranean basin, a large spatial and temporal variation in the legume nodulation was found. Soil P availability was a major limiting factor of the rhizobial symbiosis. In order to relate the field measurements with progress in functional genomics of the symbiosis, in situ RT-PCR on nodule sections has been implemented showing that the phytase gene is expressed in the cortex with significantly higher number of transcripts in P-efficient RILs. It is concluded that various tools and indicators are available for developing the ecological engineering of the rhizobial symbiosis, in particular for its beneficial contribution to the bio-geochemical cycle of N, and also P and C.

An ANN-based Approach for Forecasting the Power Output of Photovoltaic System

Abstract: With the increasing use of large-scale grid-connected photovoltaic system, accurate forecast approach for the power output of photovoltaic system has become an important issue. In order to forecast the power output of a photovoltaic system at 24-hour-ahead without any complex modeling and complicated calculation, an artificial neural network based approach is proposed in this paper. The improved back-propagation learning algorithm is adopted to overcome shortcomings of the standard back-propagation learning algorithm. Similar day selection algorithm based on forecast day information is proposed to improve forecast accuracy in different weather types. Forecasting results of a photovoltaic system show that the proposed approach has a great accuracy and efficiency for forecasting the power output of photovoltaic system.

A method of SVM with Normalization in Intrusion Detection

Abstract: Network intrusion is always hidden in a mass of routine data and the differences between these data are very large. Normalization can help to speed up the learning phase and avoiding numerical problems such as precision loss from arithmetic overflows. Some normalization methods are analyzed and simulated. Experiments results show that the method using SVM with normalization has much better performance compared to the method using SVM without normalization in classing intrusion data of KDD99 and Min-Max Normalization has better performance in speed, accuracy of cross validation and quantity of support vectors than other normalization methods.

Assessment of Soil Heavy Metal Pollution with Principal Component Analysis and Geoaccumulation Index

Abstract: The assessment of pollution levels of heavy metals soil contamination is significant to human health and environmental management. The purpose of this article is to apply two methods, which are Principal component analysis (PCA) and Geoaccumulation index ( I geo ), to assess heavy metals contamination levels in the area around copper mine tailing, and to compare the results with Hakanson potential ecological risk index techniques (RI). The rank of soil Cd pollution levels, which is assessed using I geo , is consistent with the one by RI, while the PCA assessments result of comprehensive contamination level in soil discrepancy with RI and I geo . PCA concerned with the distribution of all elements in soil, while I geo and RI are mainly determined by the elements with high concentration or big Toxic Response Factor value. The combined application of PCA and I geo can effectively identify the comprehensive and single pollution levels of elements in soil, thus important to the extent determination of heavy metals pollution in soil.

Removal of Chromium (VI) from polluted water using carbon nanotubes supported with activated carbon

Abstract: The environmental application of carbon nanotubes supported by activated carbon to remove chromium (VI) ions from polluted water was investigated. The experimental conditions that enhance the adsorption of Cr (VI) by carbon nanotubes have been studied. These conditions include the initial concentration of Cr (VI), the pH, the dosage of adsorbent, the contact time and the agitation speed. The activated carbon either alone or being coated with carbon nanotubes has be characterized by field emission scanning electron microscopy. A fractional factorial design was used to obtain a complete randomize experiment statistically. Adsorption isotherms have been applied to study the kinetics of the adsorption behavior and to determine the adsorption capacity of the absorbents. Regression analysis was used to study the empirical statistics of the experiment and to identify the significance of the parameters used to enhance the adsorption capacity. It was found that the activated carbon coated with carbon nanotubes is considered as an excellent adsorbent to Cr (VI) ions with an adsorption capacity of 9.0 mg/g.

A Crop Monitoring System Based on Wireless Sensor Network

Abstract: This paper proposed an agricultural application of wirless sensor network. The main work is to implement two types of nodes and building sensor network. The hardware platform is constituted by data process unit, radio module, sensor control matrix, data storage flash, power supply unit, analog interfaces and extended digital interfaces. The software system adopts TinyOS which is composed of system kernel, device drivers and applications. Energy-saving algorithm is implemented in the software system. The monitoring network adopts two networking protocols. The Collection Tree Protocol is a tree-based collection protocol which consists in collecting the data generated in the network into a base station. The dissemination is the complementary operation to collection. The goal of a dissemination protocol is to reliably deliver a piece of control and synchronization instructions to every node in the network. The experimental results show us that the monitoring system is feasible for applications in precision agriculture.

Landfill leachate treatment using electrocoagulation

Abstract: This study investigated the efficiency of electrocoagulation in removing ammonia nitrogen (NH 3 -N) and chemical oxygen demand (COD) from leachate. The paper studies the factors affecting the efficiency of removing NH 3 -N and COD of leachate, such as electrode material,current density, electrolysis time, Cl − concentration and pH of solution. Treatment was carried out in a discontinuous system,and the results show that the electrocoagulation can be applied to leachate pre-treatment. The operating conditions were current density of 4.96 mA/cm 2 , the raw pH, Cl − concentration of 2319 mg/L, operating time of 90 min with Fe electrode, the highest COD and NH 3 -N removal efficiencies were 49.8% and 38.6%, respectively.

Heavy Metal Pollution in Surface Water of Linglong Gold Mining Area, China

Abstract: The concentrations and distribution patterns of lead, mercury, zinc, copper, chromium, arsenic, cadmium in surface water of Linglong deposit area were discussed. The result shows that the surface water of Linglong mining area is seriously polluted by mercury, zinc and cadmium, which of the concentration are higher than the III class of National Surface Water Quality Standard, and moderately polluted by chromium and arsenic, which of the concentration conforms to the III class national surface water quality standard, and light polluted by lead and copper, which of the concentration conforms to the II class national surface water quality standard. The concentration of heavy metals in the gold deposit areas depends upon the distance from the pollution source and scalar transport in rivulet flows, decreases along the flow direction. The concentration and distribution of heavy metal pollutants in surface water are dominated by the geochemical situation and the pollution source, but seriously affected by mining leachate and chemical wastewater discharge.

Composting fish waste and seaweed to produce a fertilizer for use in organic agriculture

Abstract: The fishing sector produces large amounts of waste in fish markets and processing industries. These by-products are mainly used in the manufacture of fish meal. However, there are other potentially valuable uses. One low-investment possibility is the elaboration of agricultural products by composting the fish remains with other marine materials such as seaweed. The main purpose of this work was to obtain a fertilizer suitable for use in organic agriculture, by composting a mix of seaweed and fish waste.

Geographically Weighted Regression Using a Non-Euclidean Distance Metric with a Study on London House Price Data

Abstract: Geographically Weighted Regression (GWR) is a local modelling technique to estimate regression models with spatially varying relationships. Generally, the Euclidean distance is the default metric for calibrating a GWR model in previous research and applications; however, it may not always be the most reasonable choice due to a partition by some natural or man-made features. Thus, we attempt to use a non-Euclidean distance metric in GWR. In this study, a GWR model is established to explore spatially varying relationships between house price and floor area with sampled house prices in London. To calibrate this GWR model, network distance is adopted. Compared with the other results from calibrations with Euclidean distance or adaptive kernels, the output using network distance with a fixed kernel makes a significant improvement, and the river Thames has a clear cut-off effect on the parameter estimations.

Air quality impact of an urban park over time

Abstract: The Urban Forest Effects (UFORE) model, a computer model designed to use tree allometric, air pollution and meteorological data to statistically estimate urban forest characteristics and various urban forest functions, was applied to the main park in the city of Florence, Italy (Cascine Park), in 1985 and 2004, in order to study how the natural and man-made evolution of the park affected its ability to control air quality. Plant data were for both the years, while climate and pollutant data were for year 2004 only, in order to remove the variability due to changes in the atmospheric variables. The results show that the forest growth compensated the losses due to cuttings and damages by extreme climatic events, so that the overall amount of pollutants removed from the air did not change from 1985 to 2004 (72.4–69.0 kg/ha). In contrast, the amount of carbon storing and biogenic volatile organic compound emission decreased over time, because of a reduction in the number of large trees and of isoprene-emitting individuals, but the results were very variable plot by plot. The species were ranked according to their ability of controlling air quality. These data can be used as a decision tool for establishing cuttings and new plantings in urban planning and their effects on air quality under Mediterranean climate conditions.

Water Body Extraction Methods Study Based on RS and GIS

Abstract: Water body extraction by using remote sensing has been the most important method in the investigation of water resources, flood hazard prediction assessment and water planning with fast and accurate effectiveness. Multiple methods including unsupervised classification, supervised classification, single-band threshold, inter spectrum relation method and water index method (normalized difference water index, modified normalized difference water index, and new water index) are analyzed. Miyun reservoir and Miyun cit zone are selected as study area to find the most effective water extraction method with different usage in different time.

Waterbirds as bioindicators of wetland heavy metal pollution

Abstract: As highly developing urbanized and industrialized processes, wetland ecosystems are subject to natural and man-induced change through physical, chemical and energetic processes. Heavy metal pollution situation is more serious increasingly, water birds whose life history is in wetlands are at high risk both lethal and sub-lethal effects, as their body burdens increase. It is costly and time-consuming to determine environmental quality by examining concentrations of metals in very many organisms, thus indicator species and indicator tissues must be selected. Biological monitoring is thought to be satisfactory way to quantify heavy metal abundance and bioavailability. Waterbirds populations may serve as sentinel species for natural and man-made toxicological problems in the environment. We discussed the impacts of heavy metal polltion on the water birds in wetland ecosystems, and summaried the researches of waterbirds were used for bioindicators, especially in recent 10 years. As different parts of birds can be used to investigated the heavy metal pollution of wetland systems. We discussed the advantages and disadvantages of them, as well as water birds as monitors of the wetland quality changes in this paper.

The pair-copula construction for spatial data: a new approach to model spatial dependency

Abstract: Copulas are a flexible tool to model dependence of random variables. They cover the range from perfect negative to positive dependence, include the independent case and incorporate asymmetric dependence as well as the widely used Gaussian dependence structure. The pair-copula construction for multivariate copulas exploits the ease of bivariate copulas and suggests a decomposition of a multivariate copula into a set of bivariate ones. We successfully adapted this approach for spatial data and developed a powerful spatial pair-copula based interpolation method.

Comparison Study to Hierarchical Routing Protocols in Wireless Sensor Networks

Abstract: Routing protocol of wireless sensor network research is the key problem, according to network topology, routing protocols can be divided into flat and hierarchical routing protocol. From the basic ideas, the advantages and disadvantages and applications the article introduces several typical hierarchical routing protocols in detail, which are analyzed and compared based on performance parameters, and finally summarizes the problems of routing protocols and possible research direction in future combined with the current research status.

Multivariate Areal Interpolation for Continuous and Count Data

Abstract: Geographic information system (GIS) users often need to disaggregate and reaggregate data collected in polygons, but classical kriging models only allow for data collected in points. We discuss our implementation of areal interpolation, a kriging-based disaggregation technique, in the Geostatistical Analyst extension of ArcGIS 10.1 for Gaussian, binomial, and overdispersed Poisson data. All methods allow for surfaces of prediction standard errors. We also allow for the use of a secondary cokriging variable, which can be any of the three above-mentioned distributions. Our areal interpolation model overcomes several computational problems, such as how to handle polygons of vastly different sizes and how to analyze polygons that are overlapping or disjoint. For Gaussian data averaged over polygons, the output is a surface predicting the value at each individual location. Gaussian polygonal data may arise when continuous point measurements are averaged to polygons in order to protect privacy or reduce overhead, and the original point data is discarded. For polygons containing Poisson counts, the output is a surface predicting the density of counts at each location in the data domain. Our model allows for overdispersed counts and for different observation times between polygons. The output for binomial data is a surface predicting the underlying risk at each location of seeing an individual with a certain trait. Each polygon of the input data must contain a count and a population value. The latter indicates the number of individuals sampled, and the former indicates the number of sampled individuals with a certain trait. Once a prediction surface has been created, predictions can be aggregated back to a new set of polygons. This allows for the collection of data over one set of polygons and the prediction for a different set of polygons. We discuss diagnostic options for determining how well the data fits a model, and we demonstrate areal interpolation with three case studies.

Urban morphology of unplanned settlements: the use of spatial metrics in VHR remotely sensed images

Abstract: Information about unplanned settlements in developing cities is often unavailable, despite their extent, which at times can dominate residential land-use. This research aims to contribute to the development of tools for monitoring such areas, by using spatial metrics as means for the identification of the morphology of unplanned urban settlements in VHR images. The methodology is tested in two case study areas: Dar es Salaam and New Delhi. The methodology builds on using image segmentation and on the assumption that segments representing homogenous urban patches are different in planned and unplanned areas. The morphological aspects (size, density and layout pattern) of planned and unplanned areas are analyzed using spatial metrics on segmented images. A final set of metrics has been used to build an unplanned settlement index’. Comparison between results and land use data showed that the index can assist in the identification of unplanned settlements.

The impact of global climatic changes on the aquatic environment

Abstract: Global climatic change, as defined by the U.S. Global Change Research Act of 1990 (GCRA), “means changes in the global environment (including alterations in climate, land productivity, oceans or other water resources, atmospheric chemistry, and ecological systems) that may alter the capacity of the Earth to sustain life”. Climatic changes are the most drastic variables interacting with all live aspects of the world's development equation. Global warming, melting glaciers, sea level rise with increased coastal erosions, increased rate of lake evaporation, green house effects, increased ocean acidity, increased rates of biological invasions and deteriorated biodiversity are the interacting variables. There is a very clear fact that climatic change is not a country made product, however, it is a trans-continental issue. The abrupt surge in the catastrophic consequences of climatic changes was primarily derived from the hydrologic changes in global water that gradually moved forward toward the land. This fact puts the aquatic species on the top list of the most impacted creatures. As an ideal example for the regional impacts of global climatic changes, the coastal zones of the Levantine Mediterranean Sea at the basins of countries like Egypt, Israel and Lebanon are on an ongoing process of continuous coastal land erosions with subsequent fisheries recession due to critical damage of the breeding habitats of the native fishes at such pristine areas of the world. Further, the historical opening of Suez Canal in 1869 was a triggering force behind the development of many ecological changes in the Levantine Mediterranean as well as the Egyptian territories from the Red Sea basin. Such climatic changes have favoured the move of some invasive species like Rabbit fish and Erythrean mytilid mussel from the Red Sea to the Mediterranean Sea with their consequent huge negative impacts on the native biodiversity of the southeast Mediterranean. Other detrimental factors that will ultimately lead to great impact on the aquatic biodiversity are the inland aquaculture, eutrophication; aquatic habitat destruction and fragmentation. Thus, without a real creative international initiative to save the world's ecosystem from the colossal destructive effects of climatic changes, there will be possible endangering effects on all living creatures on planet earth.

Combining Random Forests and object-oriented analysis for landslide mapping from very high resolution imagery

Abstract: The increasing availability of very high resolution (VHR) remote sensing images has been leading to new opportunities for the cartography of landslides in risk management and disaster response. Object-oriented image analysis has become one of the key-concepts to better exploit additional spatial, spectral and contextual information. The multitude of additional object attributes calls for the use of advanced data mining and machine learning tools to identify the most suitable features and handle the non-linear classification task. In this study we used the Random Forest algorithm for the selection of useful features and object classification in the context of landslide mapping. A workflow for image segmentation, feature extraction, feature selection and classification was developed and tested with multi-sensor optical imagery from four different test sites. Due to class imbalance and class overlap between landslide and non-landslide areas the classifier can be heavily biased towards over- and under-prediction of the affected areas. This is a common issue for many real-world applications and a procedure to estimate a well-adjusted class ratio from the training samples was designed and tested. A number of potentially useful object metrics was evaluated and it was demonstrated that topographically guided texture measures provide significant enhancements. Employing 20% of the image objects for training accuracies between 73.3% and 87.1% were achieved at four different test sites.

Trace Metal Dispersion in Soil from Auto-Mechanic Village to Urban Residential Areas in Owerri, Nigeria

Abstract: Due to poor waste management in mechanic villages (MVs), average metal concentration (mgkg-1) is Pb 1162±572; Mn 864±531; Cu 385±202; Fe 49259±4770; Cd 20±13; Zn 824±190; and Ni 40±35, causing ecological and public health risks in parts of Nigeria. Average metal dispersion (mgkg-1/m) from MVs to residential areas was estimated at 9.2 for Pb; 6.7 for Mn; 6.1 for Zn; 1.5 for Cu; 197 for Fe; 0.3 for Ni; and 0.04 for Cd. This represents a mobility order of Fe>Pb>Mn>Zn>Cu>Ni>Cd, and a pollution order of Pb>Ni>Mn>Zn>Fe>Cu>Cd. MV advantages as a capacity building, and in poverty alleviation notwithstanding, its practice must be environmentally friendly.

Energy consumption and carbon emissions in a coastal city in China

Abstract: Analyses of energy consumption and carbon emissions in Tianjin are ways to understand the dynamics of developing cities in China. Using carbon emission calculation methodology recommended by IPCC, the amount of energy consumption and carbon emissions in Tianjin were calculated from 1995 to 2007. The results showed that the energy consumption structure in Tianjin relied on coal. Annual carbon emission was 26.37 million tons with growth of 4.48% per year; Sc (carbon emission per GDP) reduced year by year, and Se (carbon emission per energy consumption) decreased overall. We also proposed countermeasures to reduce carbon emissions from energy consumption.

The Construction and Application of an Aledo-NDVI Based Desertification Monitoring Model

Abstract: A desertification monitoring model was constructed and applied in a region nearby Gaotai Country, China, where undergoing a typical desertification process. First, the surface albedo and vegetation index were retrieved. And by statistical regression analysis, the quantitative relationship between albedo and NDVI of different desertification land was determined, and found they have good correlation with the coefficient 0.7707. Based on this, the model of desertification monitoring was constructed; then, using decision tree to classify the desertified land and evaluate the quantitative relationship of them by natural breaks method; finally, Quick Bird image was used to test the classifying results and the overall accuracy of the model reaches 84.071%. The study shows that the indexes of the model can reflect the desertification land surface cover, the water-heat combination and their changes. It can make full use of multi-dimensional remote sensing information and can achieve the automatic identification of desertified land.

Potential of Perennial Crop on Environmental Sustainability of Agriculture

Abstract: Since the advent of agriculture, more than one-fourth of Earth's land surface has been converted for agricultural purposes, which conversion from natural to agricultural landscapes dramatically changes the plant communities that are integral to ecosystem processes. By developing perennial crops through breeding would help deal with the multiple issues involving environmental conservation and food security in a world of shrinking resources. It can provide multiple ecosystem services essential for sustainable production more effectively than production systems based on annual crops, such as protecting against soil erosion, conserving water and nutrients, storing more carbon below ground, and building better pest tolerance. This paper presents advantages of perennial crop system in ecological benefits, introduces the important role of perennial crop at the development of sustainable agriculture, and prospects the significant utilization and potential of perennial crop on sustainability of agriculture and environment.

Lake Ecological Assessment Systems and Intercalibration for the European Water Framework Directive: Aims, Achievements and Further Challenges

Abstract: The Water Framework Directive (WFD) has been published in 2000 and the process of its implementation has created a new paradigm in the understanding of ecological status of water bodies in Europe. The Directive explicitly requires that ecological status is assessed through the analysis of various characteristics of aquatic flora and fauna. An Intercalibration exercise is foreseen to identify and resolve significant inconsistencies between the ecological quality classifications of EU Member States to ensure that the obligation to reach good status has the same meaning throughout Europe. The results of the first Lake Intercalibration exercise (2003-2008) are the setting of reference conditions and class boundaries for phytoplankton biomass metrics for all lake intercalibration types and all geographical regions of the EU. Work on macrophyte assessment methods has been carried out in the Alpine, Central/Baltic and Northern region, while only Alpine and Mediterranean countries have succeeded to develop and harmonize phytoplankton composition assessment methods. The aim of the second phase of intercalibration (2008-2011) is to close these gaps and improve the comparability of the results in time for the second river basin management plans due in 2015.

Effect of Solution pH on the Carbon Microsphere Synthesized by Hydrothermal Carbonization

Abstract: Carbon microspheres(CMSs) in a diameter of 10colonm were prepared by the hydrothermal carbonization of starch under different solution pH value. The structures and surface chemical properties of obtained CMSs before and after carbonization were characterized and compared by SEM images, nitrogen adsorption isotherms and FT-IR spectra. The results showed that the suitable solution pH value of hydrothermal carbonization ranged from 3 to 7, whereas starting pH of 1 only accelerated the hydrolysis of starch and the formation of microsphere in the early stage of the reaction. The surface chemical groups of the carbon microsphere determined its adsorption on acetic acid, while the porous structure took the role on adsorption after carbonization at 600 °C for 2 h.

Influence of meteorological conditions on summer ozone levels in the central Kanto area of Japan

Abstract: We investigated the influence of meteorological factors that affect ozone in summer using both measurement analysis and numerical simulation. The results show that there is a close relationship between changes in meteorological conditions and variations in ozone concentrations over the central Kanto area. In summer, up to 84% of long-term variations in peak ozone concentrations may be accounted for by changes in the seasonally averaged daily maximum temperatures and seasonally averaged wind speeds. The ozone episodes in the Kanto region are dominated by three major patterns, of which Patterns I and II are regular summertime pressure patterns with a 26% and 16% frequency of occurrence, respectively. A detailed process analysis of ozone formation under urban heat island (UHI) at two areas in the Kanto region – urban and rural area – indicates that ozone formation is mainly controlled by chemistry, dry deposition, vertical transport, and horizontal transport processes. The groundlevel ozone concentrations are enhanced mainly by the vertical mixing of ozone-rich air from aloft, whereas dry deposition process mainly depletes ozone. Horizontal transport and chemistry processes play opposite roles in the net change of ozone concentration between the two areas. The results of numerical simulations also indicate that the sea breeze has significant effects on the ozone accumulation and distribution in the Kanto area. The high ozone was first observed in urban area and then was transported to the rural area by sea breeze. At rural area, the highest ozone concentrations were found in late afternoon, about two hours later in comparison with the urban area.

Experimental and Theoretical Investigation of Nonlinear Flow in Low Permeability Reservoir

Abstract: Taking low permeability cores of Daqing oilfield for example, the flow characteristics at low velocity were studied by using the self-designed micro-flux measuring instrument. Considering the throat distribution and capillary model, the thickness of fluid boundary layer under different pressure gradient was calculated, the mechanism and influencing factors of nonlinear percolation were discussed. The study showed that the percolation curve of ultra-low rocks was nonlinear, and apparent permeability was not a constant, which increased with pressure gradient. The absorption boundary layer decreased with the increase of pressure gradient, and changed significantly especially in low pressure gradient, which was the essence of bringing nonlinear percolation. The absorption boundary layer was also found to be impacted by surface property of rocks, and then impacted flow characteristics.

GIS Techniques for Watershed Delineation of SWAT Model in Plain Polders

Abstract: Watershed delineation based on digital elevation models (DEMs) is the prerequisite to set up SWAT model. With topography and hydrologic processes different from the mountainous area, the watershed delineation in plain polders faces three problems: (1) the subbasins and reaches delineated from the DEM do not agree well with the realistic ones; (2) the braided streams cannot be identified by SWAT model; (3) routing processes are affected by the water-control projects seriously. Based on ArcGIS and ArcSWAT, improved DEM-based method and pre-defined method were applied in watershed delineation. In the first method, “Burn-in” and drawing reach and subbasin boundary manually were applied. First, the digital channel network (DCN) was imported using the “Burn-in” function, and the streams and subbasins were delineated based on DEM and DCN. Then the “watershed” and “reach” layers were edited in ArcGIS, where the location, range, and hydrologic connection could be adjusted. In the second method, streams and subbasins could be drawn manually or re-edited. In conclusion, the watershed delineation results using both methods agreed well with the realistic hydrologic processes in polder area and could meet the demands of the following model setup.

Characteristics of Particle Size Distributions About Emissions in A Common-rail Diesel Engine with Biodiesel Blends

Abstract: Test of particle size distributions are carried out by using the TSI3090 EEPSTM particle size spectrometer and a two- stage dilution system on a high-pressure common rail diesel engine. Analysis of the particle size distributions reveals the physical and chemical characteristics of the biodiesel fuels. The results show that sizes of particle emissions are mostly below 300 nm. Particle size of biodiesel fuel is a bimodal distribution with the number of the nucleation mode accounting for more than 60% of the total particles. With the proportion increase of biodiesel, the number of particles in nucleation mode increases while the accumulation mode particles with a size > 50 nm decreases and the peak area shifts to the small particle size. Particle size distributions of the petroleum diesel show a single peak between 50 ∼ 100 nm region and majority of the particles shows accumulation mode. Engine load has great impact on the particle size distribution, as the load increases the proportion of the nucleation mode decreases.

Application of geographically weighted regression for modelling the spatial structure of urban heat island in the city of Wroclaw (SW Poland)

Abstract: Geographically weighted regression (GWR) and Multiple Linear Regression (MLR) models have been applied to derive the spatial structure of urban heat island (UHI) in Wroclaw, SW Poland and compared. It was found that GWR is better suited for spatial modeling of UHI than MLR, as it takes into account non-stationarity of the spatial process. Both local and global models were extended by the interpolation of regression residuals, and used for spatial interpolation of the UHI structure. The combined: GWR + interpolated regression residuals (GWRK) approach is recommended for spatial modeling of UHI © 2010 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Spatial Statistics2011