Spatial sensitivity analysis of multi-criteria weights in GIS-based land suitability evaluation

With growing interest in extending GIS to support multi-criteria decision-making (MCDM) methods, enhancing GIS-based MCDM with sensitivity analysis (SA) procedures is crucial to understand the model behavior and its limitations. This paper presents a novel approach of examining multi-criteria weight sensitivity of a GIS-based MCDM model. It explores the dependency of model output on the weights of input parameters, identifying criteria that are especially sensitive to weight changes and to show the impacts of changing criteria weights on the model outcomes in spatial dimension. A methodology was developed to perform simulations where the weights associated with all criteria used for suitability modelling were varied one-at-a-time (OAT) to investigate their relative impacts on the final evaluation results. A tool which incorporates the OAT method with the Analytical Hierarchy Process (AHP) within the ArcGIS environment was implemented. It permits a range of user defined simulations to be performed to quantitatively evaluate model dynamic changes, measures the stability of results with respect to the variation of different parameter weights, and displays spatial change dynamics. A case study of irrigated cropland suitability assessment addressing the application of the new GIS-based AHP-SA tool is described. It demonstrates that the tool is spatial, simple and flexible.     

Experimental analysis and numerical modelling of the forming process of polypropylene replicas of micro-cavities using hot embossing

Numerical modelling of the deformation of a polymer using the finite elements method in axisymetrical mode was performed using the LsDyna^® software to describe the filling of micro-cavities during the forming process of the material using the hot embossing. These simulations firstly allow verifying whether the chosen forming process conditions promote or not an optimized filling of the superficial cavities in order to achieve precise replicas which best reproduce the superficial topography of the mould. The simulations were carried out to evaluate the filling of the cavities taking into account the mechanical behaviour of the selected polymer into the model. Moreover, these models were developed to verify the effect of the distribution of the mould cavities on their filling. The influence of the mobility of non deformable rigid plates on the filling of the cavities represents an auxiliary variable. In the approach presented, the compression plates are assumed to be parallel and non deformable, whereas the polymer disk follows a rubbery behaviour around a temperature equal to 140°C. Globally the modelling results are satisfactory for they are rather close to the experimental observations conducted. In summary, the effect of the normal stress as also the distribution of micro-cavities at the mould surface seem to prevail in the case of the forming process by hot embossing.     

Consumption-related development in microelectroforming

 High-aspect ratio microelectroforming is one of the most challenging techniques in MEMS microfabrication. This is particularly true with plating metal into the very tall micropatterned polymer molds made by X-ray lithography for primary or secondary metal structures or metal mold inserts within the framework of the LIGA process. Among various problems are: (1) the time consumption in plating very tall parts or using microelectroplating as a replication technique; (2) the cost of material, in particular in the formation of very high-aspect-ratio absorber structures for X-ray masks in the deep and ultra-deep X-ray lithography step. Received: 7 July 2000/Accepted: 23 August 2000     

MCMC data association and sparse factorization updating for real time multitarget tracking with merged and multiple measurements

In several multitarget tracking applications, a target may return more than one measurement per target and interacting targets may return multiple merged measurements between targets. Existing algorithms for tracking and data association, initially applied to radar tracking, do not adequately address these types of measurements. Here, we introduce a probabilistic model for interacting targets that addresses both types of measurements simultaneously. We provide an algorithm for approximate inference in this model using a Markov chain Monte Carlo (MCMC)-based auxiliary variable particle filter. We Rao-Blackwellize the Markov chain to eliminate sampling over the continuous state space of the targets. A major contribution of this work is the use of sparse least squares updating and downdating techniques, which significantly reduce the computational cost per iteration of the Markov chain. Also, when combined with a simple heuristic, they enable the algorithm to correctly focus computation on interacting targets. We include experimental results on a challenging simulation sequence. We test the accuracy of the algorithm using two sensor modalities, video, and laser range data. We also show the algorithm exhibits real time performance on a conventional PC     

Photocatalytic effect of carbon-modified n-TiO2 nanoparticles under visible light illumination

The present research focused on wet process synthesis of visible light active carbon-modified (CM)-n-TiO₂ nanoparticles and their photocatalytic activity. The CM-n-TiO₂ was synthesized by hydrolysis of TiCl₄ in the presence of tetrabutylammonium hydroxide and also in the presence of glucose and sodium hydroxide. UV–vis spectra, X-ray diffraction (XRD), and FT-IR were used to characterize these photocatalysts. It was found that the CM-n-TiO₂ nanoparticles synthesized by hydrolysis with tetrabutylammonium hydroxide or with sodium hydroxide and glucose when subjected to extended aging and subsequent calcinations absorb well into the visible to near infrared region up to 800 nm and exhibit enhanced visible light photocatalytic activity on degradation of 4-chlorophenol. CM-n-TiO₂ synthesized using glucose as the carbon source generated 13-fold increase in the initial rate of photodegradation of 4-chlorophenol compared to those by regular n-TiO₂, whereas, it increased only eight-fold when tetrabutylammonium hydroxide was used as the carbon source.     

Mixture equations of state: Composition dependence

This paper discusses theoretical models for the composition dependence of equations of state and compares the quality of predictions against experimental thermodynamic property data. The mean density approximation (MDA) and the van der Waals one-fluid (VDW1) model are compared with hybrid mixing rules (HMR), in which rigorous composition dependence is used for the second and third virial coefficients and the conformai solution model is used for equation-of-state density terms beyond the third virial term. It is found that when values of unity are used for all binary and three-body unlike interaction parameters, calculated densities for methane-normal heptane mixtures have average absolute deviations of 3.54% for MDA, 4.04% for VDW1, and 2.59% for HMR. When vapor-liquid equilibrium calculations were performed for the methane-normal heptane system, average absolute deviations of calculatedK values from experimental values were 16.7% for methane and 36.4% for normal heptane using HMR, whereas when conformal solution model (CSM) mixing rules were used, the results were 34.8% for methane and 66.7% for normal heptane. When the binary interaction parameter for the characterization of interaction energies is determined, it is found to be less sensitive to state conditions in the case of HMR than either MDA or VDW1. These preliminary results suggest the potential of mixture equation-of-state methods which utilize rigorous composition dependence for the lower-order virial coefficients.Paper presented at the Second U.S.-Japan Joint Seminar on Thermophysical Properties, June 23, 1988, Gaithersburg, Maryland, U.S.A.     

Preparation and thermophysical properties of nano-sized Ln2Zr2O7 (Ln?=?La, Nd, Sm, and Gd) ceramics with pyrochlore structure

Rare earth zirconates (Ln₂Zr₂O₇, Ln = La, Nd, Sm, and Gd) with pyrochlore structure were prepared by hydrothermal method with polyethylene glycol as surfactant. X-ray diffraction, thermogravimetric analysis/differential scanning calorimetry, Fourier transform infrared spectroscopy, Raman spectroscopy, and field emission scanning electron microscopy were utilized to characterize the phase structure, thermal decomposition, and morphology of the products. Qualitative analysis indicates that the as-prepared zirconates are pyrochlore-type structures. The specific surface area, lattice parameter, and average crystallite size of the as-prepared products are closely related to the ionic radius. The activation energy of crystal growth shows an increasing trend with the decrease in ionic radii. The sintering behavior of compacted body was also investigated, revealing that the sintering-resistance properties of Ln₂Zr₂O₇ are descending as the order of La₂Zr₂O₇, Nd₂Zr₂O₇, Sm₂Zr₂O₇, and Gd₂Zr₂O₇.     

Association Mechanism and Conformational Changes in Trypsin on Its Interaction with Atrazine: A Multi- Spectroscopic and Biochemical Study with Computational Approach

Atrazine (ATR) is a herbicide globally used to eliminate undesired weeds. Herbicide usage leads to various adverse effects on human health and the environment. The primary source of herbicides in humans is the food laced with the herbicides. The ATR binding to trypsin (TYP) was investigated in this study to explore its binding potential and toxicity. In vitro interaction of ATR with TYP was studied using multi-spectroscopic methods, molecular docking, and enzyme kinetics to explore the mechanism of binding for the TYP-ATR system. The TYP-ATR complex revealed binding constants (10³ M⁻¹), suggesting a moderate binding. The free energy for the TYP-ATR complexes was negative, suggesting a spontaneous interaction. Thermodynamic parameters enthalpy (ΔH) and entropy (ΔS) obtained positive values for the TYP-ATR system suggesting hydrophobic interactions in the binding process. Micro-environmental and conformational changes in TYP molecules were induced on interaction with ATR. Reduced catalytic activity of TYP was observed after interaction with ATR owing to the changes in the secondary structure of the TYP.     

Effect of V doping concentration on the electronic structure,optical and photocatalytic properties of nano-sized V-doped anatase TiO2

V-doped TiO₂ with V/Ti ratio of 1–5% has been synthesized by hydrothermal method and then characterized by XRD, TEM, BET specific surface area, XPS and UV–vis. absorption spectra. The photocatalytic activity of the as-synthesized samples was investigated by the degradation of methylene blue in aqueous solution under visible light irradiation. Density functional theory (DFT) based calculations were performed to investigate the mechanism of band gap narrowing, the shift of light absorption edge, the location of V in the TiO₂ lattice and the variation in electronic and optical properties of TiO₂ with the increase of V doping concentration. Irrespective of the V doping concentration, TEM images indicate that all the doped samples were composed of equiaxed spherical anatase TiO₂ particles with good crystallinity and uniform particle size distribution. Both the experimental results from XPS survey and the theoretical calculation argue that the doped V replaces the lattice Ti and form substitutional impurity. The visible light absorption can be optimized by adjusting the V doping concentration. Among the doped samples with different V doping concentrations, the sample with V/Ti ratio of 2% depicts better visible light photocatalytic activity due to the enhanced visible light absorption and improved separation of electron–hole pairs.     

Single-Circulating Tumor Cell Whole Genome Amplification to Unravel Cancer Heterogeneity and Actionable Biomarkers

The field of single-cell analysis has advanced rapidly in the last decade and is providing new insights into the characterization of intercellular genetic heterogeneity and complexity, especially in human cancer. In this regard, analyzing single circulating tumor cells (CTCs) is becoming particularly attractive due to the easy access to CTCs from simple blood samples called “liquid biopsies”. Analysis of multiple single CTCs has the potential to allow the identification and characterization of cancer heterogeneity to guide best therapy and predict therapeutic response. However, single-CTC analysis is restricted by the low amounts of DNA in a single cell genome. Whole genome amplification (WGA) techniques have emerged as a key step, enabling single-cell downstream molecular analysis. Here, we provide an overview of recent advances in WGA and their applications in the genetic analysis of single CTCs, along with prospective views towards clinical applications. First, we focus on the technical challenges of isolating and recovering single CTCs and then explore different WGA methodologies and recent developments which have been utilized to amplify single cell genomes for further downstream analysis. Lastly, we list a portfolio of CTC studies which employ WGA and single-cell analysis for genetic heterogeneity and biomarker detection.