Estimating Model Parameters of Conditioned Soils by using artificial network

Abstract—The parameter identification of nonlinear constitutive model of soil mass is based on an inverse analysis procedure, which consists of minimizing the objective function representing the difference between the experimental data and the calculated data of the mechanical model. The ill-poseness of inverse problem is discussed. The classical gradient-based optimization algorithm for parameter identification is also investigated. Neural network models are developed for estimating model parameters of conditioned soils in EBP shield. The weights of neural network are trained by using the Levenberg-Marquardt approximation which has a fast convergent ability. The parameter identification results illustrate that the proposed neural network has not only higher computing efficiency but also better identification accuracy. The results from the model are compared with simulated observations. The models are found to have good predictive ability and are expected to be very useful for estimating model parameters of conditioned soils in EBP shield. Index Terms—parameter estimation, neural network, inverse problem, shield machin

Freshwater Supply to Metropolitan Shanghai: Issues of Quality from Source to Consumers

Shanghai is experiencing drinking water supply problems that are caused by heavy pollution of its raw water supply, deficiencies in its treatment processes, and water quality deterioration in the distribution system. However, little attention has been paid these problems of water quality in raw water, water treatment, and household drinking water. Based on water quality data from 1979 to 2016, we show that microbes (TBC), eutrophication (TP, TN, and NH3–N), heavy metals (Fe, Mn, and Hg), and organic contamination (chemical oxygen demand (COD), detergent (Linear Alklybenzene Sulfonate, LAS), and volatile phenols (VP)) pollute the raw water sources of the Huangpu River and the Changjiang (Yangtze River) estuary. The average concentrations of these contaminants in the Huangpu River are almost double that of the Changjiang estuary, forcing a rapid shift to the Changjiang estuary for raw water. In spite of filtering and treatment, TN, NH3–N, Fe, COD, and chlorine maxima of the treated water and drinking water still exceed the Chinese National Standard. We determine that the relevant threats from the water source to household water in Shanghai are: (1) eutrophication arising from highly concentrated TN, TP, COD, and algal density in the raw water; (2) increasing salinity in the river estuary, especially at the Qingcaosha Reservoir (currently the major freshwater source for Shanghai); (3) more than 50% of organic constituents and by-products remain in treated water; and, (4) bacteria and turbidity increase in the course of water delivery to users. The analysis presents a holistic assessment of the water quality threats to metropolitan Shanghai in relation to the city’s rapid development

Electrochemical Evaluation of trans-Resveratrol Levels in Red Wine Based on the Interaction between Resveratrol and Graphene

trans-Resveratrol is often considered as one of the quality standards of red wine, and the development of a sensitive and reliable method for monitoring the trans-resveratrol levels in red wine is an urgent requirement for the quality control. Here, a novel voltammetric approach was described for probing trans-resveratrol using a graphene-modified glassy carbon (GC) electrode. The proposed electrode was prepared by one-step electrodeposition of reduced graphene oxide (ERGO) at a GC electrode. Compared with the bare GC electrode, the introduced graphene film on the electrode surface dramatically improved the sensitivity of the sensor response due to the π-π interaction between the graphene and trans-resveratrol. The developed sensor exhibited low detection limit of 0.2 μM with wide linear range of 0.8–32 μM and high stability. For the analysis of trans-resveratrol in red wine, the high anti-interference ability and the good recoveries indicated the great potential for practical applications

Lateral Ge segregation and strain evolution in SiGe alloys during the formation of nickel germano-silicide on a relaxed Si073Ge 027 epilayer

Ge segregation and strain evolution in the SiGe alloys during the formation of nickel germano-silicide on a relaxed Si0.73Ge0.27 epilayer are studied in temperature range of 300-900°C. The continuous NiSiGe film on SiGe epilayer is formed at 500°C and below, which applies tensile stress on the underlying unreacted SiGe layer. When temperature rises to 600°C and above, the NiSiGe film begins to agglomerate, resulting in the formation of Ge-rich SiGe regions scattering among NiSiGe grains in the surface due to Ge lateral segregation from NiSiGe. During these processes, Ge is preferentially rejected from the NiSiGe grains giving rise to the transformation of NiSiGe to NiSi with increase of temperature and the increase of Ge content in the Ge-rich SiGe at the NiSiGe grain boundaries. The enlarged lattice constant of Ge-rich SiGe and the volume expansion of NiSiGe grains make the Ge-rich SiGe alloy under compressive strain. No significant Ge segregation is observed between Ni(SiGe) and the underlying SiGe layer even at higher temperature. ? 2013 AIP Publishing LLC

Lateral Ge segregation and strain evolution in SiGe alloys during the formation of nickel germano-silicide on a relaxed Si073Ge027 epilayer

National Basic Research Program of China [2012CB933503, 2013CB632103]; National Natural Science Foundation of China [61176092, 61036003, 60837001]; Ph.D. Programs Foundation of Ministry of Education of China [20110121110025]; Fundamental Research Funds for the Central Universities [2010121056]Ge segregation and strain evolution in the SiGe alloys during the formation of nickel germano-silicide on a relaxed Si0.73Ge0.27 epilayer are studied in temperature range of 300-900 degrees C. The continuous NiSiGe film on SiGe epilayer is formed at 500 degrees C and below, which applies tensile stress on the underlying unreacted SiGe layer. When temperature rises to 600 degrees C and above, the NiSiGe film begins to agglomerate, resulting in the formation of Ge-rich SiGe regions scattering among NiSiGe grains in the surface due to Ge lateral segregation from NiSiGe. During these processes, Ge is preferentially rejected from the NiSiGe grains giving rise to the transformation of NiSiGe to NiSi with increase of temperature and the increase of Ge content in the Ge-rich SiGe at the NiSiGe grain boundaries. The enlarged lattice constant of Ge-rich SiGe and the volume expansion of NiSiGe grains make the Ge-rich SiGe alloy under compressive strain. No significant Ge segregation is observed between Ni(SiGe) and the underlying SiGe layer even at higher temperature. (C) 2013 AIP Publishing LLC