Spatial Distribution Factors Research Articles

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ КУЧНОГО ВЫЩЕЛАЧИВАНИЯ ЗОЛОТА В РУДНОМ ШТАБЕЛЕ (НА МЕСТОРОЖДЕНИИ «ДЕЛЬМАЧИК»)

Recently, due to the clearly expressed tendency to involve poor ores with a low content of a valuable component in the exploitation, heap leaching technology has been increasingly used. As a rule, it is sold on small reserves and sizes of ore deposits. For example, in the Transbaikal Territory, the number of developed gold-bearing de posits and potentially suitable for the development by heap leaching technology of a valuable component today is about 31. Moreover, deposits, as a rule, are located on the territory represented by frozen and permafrost soils. They are characterized by harsh climatic conditions and low-snow winters. One of the promising areas of the research is the method of block modeling, which, with the development of information technology, acquires special significance and is aimed at solving the urgent problem of three-dimensional modeling. Its main advantage is that it allows you to quantify the spatial distribution of factors, as well as the dynamics of their changes over time. The object of research is an ore stack of a technogenic deposit. The subject of the study is mathematical modeling of gold heap leaching. The purpose of the study is to develop a method for block modeling of gold heap leaching in an ore stack and a methodology for its implementation. The research methodology is the use of the regularities of filtration and physico-chemical seepage of leaching solutions through the porous medium of the ore stack. Research methods are the following: physical and mathematical methods modeling of heap leaching processes; use of statistical methods to identify patterns of spatial distribution of factors affecting the heap leaching process; use of software products (geoinformation systems) for data visualization

GIS-based comparative characterization of groundwater quality of Tabas basin using multivariate statistical techniques and computational intelligence

Effective management of groundwater resources needs sustainable monitoring programs which are mainly performed based on water quality characterization. In the current research, hydrochemical characteristics of Tabas basin groundwater were analyzed by self-organizing map (SOM), multivariate statistical analysis and average groundwater quality index (AGWQI). Geographic information system was adopted to highlight the spatial variability of water indices, factors and clusters. AGWQI results show inappropriateness of groundwater for drinking purposes in some central and western parts of the study area (AGWQI > 100). A three-component model which explains over 80.75% of the total groundwater quality variations was suggested after factor analysis. Factor 1 (natural hydrochemical evolution of groundwater) includes high loadings of EC, TDS, TH, Ca2+ and Na+, Factor 2 (weathering and dissolution processes) includes high loadings of pH, Mg2+, HCO3− and depth, and Factor 3 (anthropogenic activities) includes high loadings of K+, Cl−, SO42− and NO3−. As the main goal of this study, groundwater data were also examined using SOM approach. Based on hydrochemical characteristics, groundwater samples were divided into three clusters. Cluster I containing 14% of groundwater samples (and sampling stations) is characterized by higher TDS, EC and TH values. Clusters II (characterized by higher Mg2+ concentration) and III (characterized by higher NO3− concentration) represent 50% and 36% of samples, respectively. Maps drawn show a meaningful compatibility among the spatial distribution of factors and clusters. This study proves that SOM can be successfully applied to characterize and classify groundwater in terms of quality on a regional scale.

Investigating the impact of catchment areas of airports on estimating air travel demand: A case study of regional Western Australia

The aviation industry in Western Australia (WA) plays a vital role in the economic and social development of the state. However, accurate forecasts for passenger movements are not available to policy makers due to lack of relevant air travel demand information. The objective of this study is to estimate the domestic air passenger seat numbers between airport-pairs based on online flight information in regional WA based on a gravity model using Poisson pseudo-maximum likelihood estimation (PPML). Particularly, we aim to investigate the impact of distance, airfare, catchment areas, population, tourism and mining sector on forecasting air passenger seat numbers in order to inform and guide policy making.This research collected appropriate data and produced valid models that represent air passenger seat numbers offered on regular public transport (RPT) air services in regional WA. The models consider both geographic and service-related variables, such as the catchment area of airports, population and number of tourists in the airport's catchment area. Two kinds of airport catchment areas are generated in this study, based on Thiessen polygon and two and half hours' driving distance. The Thiessen polygon catchment areas cover the whole WA regions, while the 2.5 h's driving catchment area covers only 32 percent of the WA region. The size of the catchment area can affect the magnitude of factors, and therefore influence the modelling results. When deciding the catchment area for the study, it is important to take the spatial distribution of factors into considerations. For both Thiessen polygon and two and half hours' driving distance catchment area, the model results illustrate that distance between airports, airfare of the flight, population of the origin airport's catchment area and the number of operating mine sites of the destination airport's catchment area are significantly correlated with domestic air travel seat capacity provided. Given the guidance from policy documents and policy makers, the results will improve the understanding of the key parameters of regional passenger aviation services and help to guide policy makers considering regional passenger aviation issues. The outcome of this study would be useful for and guide policy development.

Microfluidics embedded within extracellular matrix to define vascular architectures and pattern diffusive gradients

Gradients of diffusive molecules within 3D extracellular matrix (ECM) are essential in guiding many processes such as development, angiogenesis, and cancer. The spatial distribution of factors that guide these processes is complex, dictated by the distribution and architecture of vasculature and presence of surrounding cells, which can serve as sources or sinks of factors. To generate temporally and spatially defined soluble gradients within a 3D cell culture environment, we developed an approach to patterning microfluidically ported microchannels that pass through a 3D ECM. Micromolded networks of sacrificial conduits ensconced within an ECM gel precursor solution are dissolved following ECM gelation to yield functional microfluidic channels. The dimensions and spatial layout of channels are readily dictated using photolithographic methods, and channels are connected to external flow via a gasket that also serves to house the 3D ECM. We demonstrated sustained spatial patterning of diffusive gradients dependent on the architecture of the microfluidic network, as well as the ability to independently populate cells in either the channels or surrounding ECM, enabling the study of 3D morphogenetic processes. To highlight the utility of this approach, we generated model vascular networks by lining the channels with endothelial cells and examined how channel architecture, through its effects on diffusion patterns, can guide the location and morphology of endothelial sprouting from the channels. We show that locations of strongest gradients define positions of angiogenic sprouting, suggesting a mechanism by which angiogenesis is regulated in vivo and a potential means to spatially defining vasculature in tissue engineering applications. This flexible 3D microfluidic approach should have utility in modeling simple tissues and will aid in the screening and identification of soluble factor conditions that drive morphogenetic events such as angiogenesis.

Spatial distribution of factors that determine sporogonic development of malaria parasites in mosquitoes

Mosquitoes transmit malaria, but only a few species permit the complete development and transmission of the parasite. Also, only a fraction of the ingested parasites develop in the vector. The attrition occurs in different compartments during the parasite's complex developmental scheme in the insect. A number of factors, both physical and biochemical, that affect the development have been proposed or demonstrated. Each of these factors is located within a specific space in the insect. We have divided this space into six compartments, which are distinct in their biochemical and biophysical nature: Endoperitrophic space, Peritrophic matrix, Ectopretrophic space, Midgut epithelium, Haemocoel and Salivary gland. Because factors that influence a particular stage of parasite development share the same microenvironment within these compartments, they must be considered collectively to exploit them for designing effective transmission blocking strategies. In this article we discuss these factors according to their spatial location in the mosquito.