EVOLUTION FILTRATION PROBLEMS WITH SEAWATER INTRUSION: TWO-PHASE FLOW DUAL MIXED VARIATIONAL ANALYSIS

Tow-phase flow mixed variational formulations of evolution filtration problems with seawater intrusion are analyzed. A dual mixed fractional flow velocity-pressure model is considered with an air-fresh water and a fresh water-seawater characterization. For analysis and computational purposes, spatial decompositions based on nonoverlapping multidomains, above and below the sea level, are variationally introduced with internal boundary fluxes dualized as weak transmission constraints. Further, parallel augmented and exactly penalized duality algorithms, and proximation semi-implicit time marching schemes, are established and analyzed.

A MIXED VARIATIONAL FORMULATION FOR LARGE DEFORMATION ANALYSIS OF PLATES

A mixed vuriational formulation for large deformation analysis of plates is introduced. In this formulation the equilibrium ami compatibility equations are satisfied identically by means of stress functions and displacement components, respectively, and the constitu,lye equations are satisfied in a least square sense. An example is solved and the results are compared with those available in the literature.Further, the functional is particularized for buckling analysis of plates and a simple example is solved to illustrate the theory.

Application of a mixed DEA model to evaluate relative efficiency validity

Data envelopment analysis(DEA) model is widely used to evaluate the relative efficiency of producers. It is a kind of objective decision method with multiple indexes. However, the two basic models frequently used at present, the C2R model and the C2GS2 model have limitations when used alone,resulting in evaluations that are often unsatisfactory. In order to solve this problem, a mixed DEA model is built and is used to evaluate the validity of the business efficiency of listed companies. An explanation of how to use this mixed DEA model is offered and its feasibility is verified.

Mixed convection heat transfer in horizontal channel filled with nanofluids

The laminar fully developed nanofluid flow and heat transfer in a horizonal channel are investigated. Highly accurate solutions for the temperature and nanopavticle concentration distributions are obtained. The effects of the Brownian motion parameter Nb, the thermophoresis parameter Nt, and the Lewis number Le on the temperature and nanoparticle concentration distributions are discussed. The current analysis shows that the nanoparticles can improve the heat transfer characteristics significantly for this flow problem.

A Topological Clustering of Variables

The clustering of objects(individuals or variables)is one of the most used approaches to exploring multivariate data.The two most common unsupervised clustering strategies are hierarchical ascending clustering(HAC)and k-means partitioning used to identify groups of similar objects in a dataset to divide it into homogeneous groups.The proposed topological clustering of variables,called TCV,studies an homogeneous set of variables defined on the same set of individuals,based on the notion of neighborhood graphs,some of these variables are more-or-less correlated or linked according to the type quantitative or qualitative of the variables.This topological data analysis approach can then be useful for dimension reduction and variable selection.It’s a topological hierarchical clustering analysis of a set of variables which can be quantitative,qualitative or a mixture of both.It arranges variables into homogeneous groups according to their correlations or associations studied in a topological context of principal component analysis(PCA)or multiple correspondence analysis(MCA).The proposed TCV is adapted to the type of data considered,its principle is presented and illustrated using simple real datasets with quantitative,qualitative and mixed variables.The results of these illustrative examples are compared to those of other variables clustering approaches.

Study on cobalt-carbon and iron-sulfur mixed cluster complexes——Synthesis and conformational analysis of mixed cluster complexes [μ-p-CH_3C_6H_4C_2Co_2 (CO)_6 S](μ-RS)Fe_2(CO)_6

Through complexation reaction of arynyl Fe-S complexes A(μ-p-CH_3C_6H_4C≡CS)(μ- RS)Fe_2(CO)_6 with Co_2(CO)_6, eight mixed cluster complexes B[μ-p-CH_3C_6H_4C_2Co_2(CO)_6S](μ- RS)Fe_2(CO)_6 have been synthesized. Reactivity of the complexation reaction is approximately equi- valent to that of the reaction of diarylacetylene with Co_2(CO)_8. Conformational analysis has shown that R groups in complexes A are linked to sulfur atoms by a-and e-bond, whereas that in B only by art e-type of bond.

Mixed Matrix Membranes of Polysulfone/Polyimide Reinforced with Modified Zeolite Based Filler: Preparation, Properties and Application

In this work, polysulfone/polyimide（PSf/PI） mixed matrix membranes were fabricated by reinforcement of modified zeolite（MZ） particles through solution casting method for investigation of antibacterial activity against two gram negative bacteria（Salmonella typhi, Klebsella pneumonia） and two gram positive bacteria（Staphylococcus aureus, Bacillus subtilis）. The modified zeolite particles were incorporated to PSf and PI matrix and the influence of these particles on thermal, mechanical and structural properties was evaluated. The morphological evolution was investigated through scanning electron microscopy（SEM） and transmission electron microscopy（TEM） analysis, which revealed good compatibility between organic polymer matrix and inorganic filler. Mechanical stability was investigated by tensile testing while thermal analysis was evaluated by thermogravimetric analysis（TGA） and differential scanning calorimetry（DSC）. This revealed improvement in thermal properties with increasing filler concentration from 1 wt% to 10 wt%. Structural analysis was successfully done using X-ray diffraction analysis（XRD） and Fourier transform infrared（FTIR） spectroscopy. Solvent content of fabricated mixed matrix membranes was observed to decrease while moving from more hydrophilic to less hydrophilic solvent. However, addition of filler content enhanced the porosity of fabricated membranes. The synthesized mixed matrix membranes exhibited good antibacterial activity and the highest activity was shown by PSf/PI/MZ mixed matrix membrane. Therefore, the combination effect of PSf, PI and MZ sufficiently enhanced the antibacterial activity of mixed matrix membranes.

Hydrological processes in the Aksu River source region during the intense ablation period based on water chemistry and isotopes

Against the backdrop of global warming,the dynamics of glaciers and their water resources have significant implications for hydrological processes in the arid regions of Northwest China.The Aksu River,which is an essential inland river enriched by substantial meltwater contributions,plays a pivotal role in the economic,ecological,and social development of the region.Based on 231 water samples collected during the period of intense glacial ablation in 2023,this study conducted a comprehensive analysis of the hydrochemical and stable isotopic characteristics of the Little Kurgan glacial basin in the Aksu River source region.A Piper diagram classified the hydrochemical type of the river water as Calcium-Bicarbonate.Analysis based on a Gibbs diagram indicated that rock weathering is the predominant factor affecting the hydrochemical properties within the studied basin.Through application of principal component analysis and end-member mixing analysis,it was determined that the glacier meltwater contribution to runoff was 67%,61%,and 55%in July,August,and September,respectively.The findings of this study reveal that glacier meltwater is the principal component of the river water,and highlight the critical impact of alterations in glacier ablation on the hydrological cycle within the Aksu River source region,which is vitally important for sustainable water resource management.

Assessment of the macro-economic impacts of low-carbon road transportation policies in Chongqing,China

Reductions in the transportation sector's carbon dioxide emissions are increasingly of global concern.As one of the first low-carbon pilot and carbon trading pilot cities,and as one of the largest automobile production bases in China,Chongqing has multiple low-carbon transportation policies that are coupled.In this study,three policy scenarios are set,including:1)improving the fuel economy of newly sold gasoline passenger cars to 5.71 per 100 km by 2020,2)promoting pure electric private cars to increase the share to 7% of private car sales by 2020,and 3)the policy mix scenario of the above two policies.Simulations are undertaken with the Chinese Academy of Sciences general equilibrium(CAS-GE)model,a type of computable GE model,to assess the macro-economic impact and the industrial impact of the three policy scenarios.Through the policy impact mechanism analysis and data-mapping process,the micro-economic impact analysis results,including costs and fuel savings,for the two policies from the bottom-up model are taken as the shock variables and inputs for the CAS-GE model.The results show that:1)the two policies will both have a slightly negative impact(-0.09% and -0.30%)on Chongqing's GDP in 2020;2)the employment rate will decrease by 0.12% and 0.47%,but the inflation rate will be restrained to a certain extent(-0.21% and -0.17%);and 3)the complementarity of the mixed policy can weaken the negative impact of the two policies when implemented separately.The mixed policy will reduce the GDP slightly by 0.37%,compared with the cumulative effect of the two policies implemented separately,resulting in cost-effective synergies at the macroeconomic impact level;and 4)the COVID-19 pandemic in 2020 has an uncertain impact on the results.The method and results can provide a reference for the formulation and adjustment of low-carbon transportation policies in other large cities.

Use of Hi-resolution data for evaluating accuracy of traffic volume counts collected by microwave sensors

Over the past few years, the Utah Department of Transportation has developed the signal performance metrics （SPMs） system to evaluate the performance of signalized in- tersections dynamically. This system currently provides data summaries for several per- formance measures, one of them being turning movement counts collected by microwave sensors. As this system became public, there was a need to evaluate the accuracy of the data placed on the SPMs. A large-scale data collection was carried out to meet this need. Vehicles in the Hi-resolution data from microwave sensors were matched with the vehicles by ground-truth volume count data. Matching vehicles from the microwave sensor data and the ground-truth data manually collected required significant effort, A spreadsheet- based data analysis procedure was developed to carry out the task. A mixed model analysis of variance was used to analyze the effects of the factors considered on turning volume count accuracy. The analysis found that approach volume level and number of approach lanes would have significant effect on the accuracy of turning volume counts but the location of the sensors did not significantly affect the accuracy of turning volume counts. In addition, it was found that the location of lanes in relation to the sensor did not significantly affect the accuracy of lane-by-lane volume counts. This indicated that accu- racy analysis could be performed by using total approach volumes without comparing specific turning counts, that is, left-turn, through and right-turn movements. In general, the accuracy of approach volume counts collected by microwave sensors were within the margin of error that traffic engineers could accept. The procedure taken to perform the analysis and a summary of accuracy of volume counts for the factor combinations considered are presented in this paper.