Groundwater monitoring of an open-pit limestone quarry:Water-rock interaction and mixing estimation within the rock layers by geochemical and statistical analyses

Water-rock interaction and groundwater mixing are important phenomena in understanding hydrogeological systems and the stability of rock slopes especially those consisting largely of moderately watersoluble minerals like calcite. In this study, the hydrogeological and geochemical evolutions of groundwater in a limestone quarry composed of three strata: limestone layer(covering), interbedded layer under the covering layer, and slaty greenstone layer(basement) were investigated. Water-rock interaction in the open-pit limestone quarry was evaluated using PHREEQC, while hierarchical cluster analysis(HCA)and principal component analysis(PCA) were used to classify and identify water sources responsible for possible groundwater mixing within rock layers. In addition, Geochemist's Workbench was applied to estimate the mixing fractions to clarify sensitive zones that may affect rock slope stability. The results showed that the changes in Ca2+and HCO3àconcentrations of several groundwater samples along the interbedded layer could be attributed to mixing groundwater from the limestone layer and that from slaty greenstone layer. Based on the HCA and PCA results, groundwaters were classified into several types depending on their origin:(1) groundwater from the limestone layer(LO),(2) mixed groundwater flowing along the interbedded layer(e.g., groundwater samples L-7, L-11, S-3 and S-4), and(3) groundwater originating from the slaty greenstone layer(SO). The mixing fractions of 41% LO: 59% SO, 64% LO: 36% SO, 43%LO: 57% SOand 25% LO: 75% SOon the normal days corresponded to groundwaters L-7, L-11, S-3 and S-4,respectively, while the mixing fractions of groundwaters L-7 and L-11(61% LO: 39% SOand 93% LO: 7% SO,respectively) on rainy days became the majority of groundwater originating from the limestone layer.These indicate that groundwater along the interbedded layer significantly affected the stability of rock slopes by enlarging multi-breaking zones in the layer through calcite dissolution and inducing high water pressure, tension cracks and potential sliding plane along this layer particularly during intense rainfall episodes.

移动闭塞的原理、系统结构及功能

阐述了移动闭塞技术的原理。介绍了典型的基于无线通信的移动闭塞系统的系统结构。分析了移动闭塞相对于传统闭塞方式的优势。

Developing a General Methodology for Driving Cycle Construction: Comparison of Various Established Driving Cycles in the World to Propose a General Approach

Many models have been developed in the world to estimate emission inventories and fuel consumption in the past and those models can be broadly categorized as either a travel based model or a fuel based model. Driving cycles can be considered as one of the major travel based models to estimate emission inventories. It can be used for various purposes such as setting up the emission standards, for traffic management purposes and also to determine the travel time. In the past, researchers have tried to use readily available, well established driving cycles in their environment which is different from the origin of the driving cycle in many aspects. Thus, the attempts have failed to give good quality results. This study attempts to critically evaluate the different methods used for driving cycle construction in different parts of the world under various conditions to propose a general suitable approach to develop a representative and economical driving cycle(s) for a given geographic location for set objectives.

High–Speed electron beam curing of thick electrode for high energy density Li-ion batteries

Electron beam curing is demonstrated as a promising method for high speed,low cost and environmentally friendly battery electrode manufacturing.This work reports transfer of this process to pilot scale equipment and evaluation of electrochemical performance in prototype 1.5 Ah pouch cells.Thick LiNi0.5Mn0.3Co0.2O2(NMC532)composite electrodes with an areal loading of 25 mg cm^-2(~4 mAh cm^-2)are successfully cured at a line speed of 500 feet per minute at 275 keV.Compared to the NMC532 cathode processed via a conventional coating method,the electron beam cured electrodes show higher capacity fade in the first 100 cycles,but similar fade rate afterwards.Further improvement strategies are proposed and discussed.This work demonstrates that electron beam curing is a promising method for manufacturing thick battery electrodes at high speeds and low capital/operation cost.

Riparian and Riverine Wildlife Response to a Newly Created Bridge Crossing

Construction of man-made objects such as roads and bridges can influence wildlife presence and abundance. We investtigated waterbirds, songbirds, anurans, turtles, small mammals, and furbearers along the Ohio River, WV, at a new bridge crossing, a 45-year old bridge, and 1 or 2 islands with no bridge and at 3 distances from the bridge or center point at each site (0 m,100 m, and300 m). We sampled 19 waterbird, 60 songbird, 7 anuran, 5 turtle, 9 small mammal, and 4 furbearer species. Great blue heron (Ardea herodias) abundances were greater at the site with no bridge. Songbird composition differed among sites and between transects under and away from the bridge with higher abundances or association of rock pigeon (Columba livia) and cliff swallow (Petrochelidon pyrrhonota) under the bridges and lower abundances ofCarolinawren (Thryothorus ludovicianus) and common yellowthroat (Geothlypis trichas) under the bridges. Total small mammal abundance, diversity, and richness were lower under the new bridge compared to other sites and distances. We conclude that overall the new bridge is causing minimal relative abundance impacts to wildlife. However, great blue heron abundance may be altered due to noise and activity from the presence of the bridge and minor short-term impacts to some songbirds and small mammals directly under the bridge in the form of habitat conversion, fragmentation, and loss due to removal of vegetation is apparent.

Spanish Initiative for the Automation in Urban Transport: AutoMOST

The progressive automation of transport will imply a new paradigm in mobility, which will profoundly affect people, logistics of goods, as well as other sectors dependent on transport. It is precise within this automation where the development of new driving technologies is going to cause a great impact on the mobility of the near future, and that will have an effect on the economic, natural and social environment. It is therefore a primary issue at the global level, as it is reflected in the work programs of the European Commission in relation to the road transport [1] [2]. Thus, the size impact is caused by the following novelties and advantages: 1) Safety: Accidents reduction caused by human error;2) Efficiency increase in transportation, both in energy consumption and time;3) Comfort for users and professionals who will increase their operational availability to execute other more valuable tasks, both for them and enterprises;4) Social Inclusion: enabling mobility easily for everybody during more time;5) Accessibility, to get to city centers and other difficult reach places. It should be noted that the economic impact projected for automated driving for the years to come ranges up to €71 bn in 2030, when estimated global market for automated vehicles is 44 million vehicles, as is reflected in document Automated Driving Roadmap by ERTRAC [3], European Road Transport Research Advisory Council (http://www.ertrac.org/uploads/documentsearch/id38/ERTRAC_Automated-Driving-2015.pdf). As background that already anticipates these im-provements, the Advance Driver Assistance System (ADAs) have already showed the safety increase in the last ten years, but always maintain a leading role for the driver. Related to the efficiency increase, automated driving offers great opportunities for those companies where mobility is a key factor in operating costs, and affects the whole value chain. The project opportunity is consistent with ERTRAC vision, especially in applications focused on the urban environment [4], where it is expected a deployment of the technology of high level automation in an immediate future. This is possible by the potential to incorporate smart infrastructure to improve guidance and positioning, as well as lower speed, which eases its progressive deployment. The objective of AutoMOST is developing technologies for the automation of vehicles in urban transport and industrial applications, to increase significantly the efficiency, safety and environmental sustainability. More specifically, AutoMOST will allow the implementation of shared control systems (Dual-Mode) [5] for future automated vehicles that allow the services operate more efficiently and flexibly, in a context of intelligent and connected infrastructures.

Temperature-dependent constitutive modeling of a magnesium alloy ZEK100 sheet using crystal plasticity models combined with in situ high-energy X-ray diffraction experiment

A multiscale crystal plasticity model accounting for temperature-dependent mechanical behaviors without introducing a larger number of unknown parameters was developed.The model was implemented in elastic-plastic self-consistent(EPSC)and crystal plasticity finite element(CPFE)frameworks for grain-scale simulations.A computationally efficient EPSC model was first employed to estimate the critical resolved shear stress and hardening parameters of the slip and twin systems available in a hexagonal close-packed magnesium alloy,ZEK100.The constitutive parameters were thereafter refined using the CPFE.The crystal plasticity frameworks incorporated with the temperature-dependent constitutive model were used to predict stress–strain curves in macroscale and lattice strains in microscale at different testing temperatures up to 200℃.In particular,the predictions by the crystal plasticity models were compared with the measured lattice strain data at the elevated temperatures by in situ high-energy X-ray diffraction,for the first time.The comparison in the multiscale improved the fidelity of the developed temperature-dependent constitutive model and validated the assumption with regard to the temperature dependency of available slip and twin systems in the magnesium alloy.Finally,this work provides a time-efficient and precise modeling scheme for magnesium alloys at elevated temperatures.

Effects of charging rates on LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2)(NMC622)/graphite Li-ion cells

Enabling fast charging capability of lithium-ion battery is of great importance to widespread adoption of electric vehicles.Increasing the charging rates from state-of-the-art 2 C(30 min)to 6 C(10 min)requires deep understanding on the cell aging mechanism.In this study,400 mAh pouch cells are cycled at 1 C,4 C and 6 C charging rates with 1 C discharging rate.Capacity fading,cathode structural changes,Li inventory loss,electrolyte composition changes and Li plating on graphite electrodes are thoroughly studied by various characterization techniques.The rapid capacity fading in cells at 6 C charging rate is mainly due to Li inventory loss from cathode structure and metallic Li plating on graphite electrode at higher charging rate.Post-mortem analysis also revealed changes in electrolyte such as increased salt molarity and transesterification during fast charging.

Displacement Pump Evolution Theories and the Innovative Design of the Pump with a Half-Sphere Rotor

Some mechanisms evolve from other mechanisms to fulfil a new function. It follows that there is cognation between certain mechanisms. Addressed in the present paper are innovative design methods for displacement machinery. According to the design of the changeable displacement pump, it may be a closed pair of components in the mechanism that possesses periodically relative movement to form a periodically changeable and closed cavity. To this can be adapted design methods based on innovative theories, such as the Scotch Cousin theory in evolution venations, the theory of Cognation, the theory of “Nodes” among generations and so on. Thus innovative designs for them can be produced by imaginative thinking. Illustrated here is an innovative design for a pump a with half-sphere rotor, developed from a typical 4-bar mechanism in accordance with the principle of Precession Evolution, which is to be applied to the recovery of oil spillage at sea.

Comparison of Design Thickness between the 1993 AASHTO Guide and MEPDG for Full Depth Reclamation Pavement

A research project was initiated by INDOT to estimate the structural contribution and feasibility of FDR bases for pavement structure under a low-medium volume traffic loading. FWD tests were conducted and the layer moduli were back calculated on different construction phases： the surface of existing HMA pavement, the FDR base, the new HMA final surface, and the nine months＇ traffic opening, respectively, for a total of four times. The results indicate the promise of this recycled base material in pavement construction compared to traditional granular base. In addition, this paper discusses how the lab test results relate to the expected performance in a pavement structure by the MEPDG software and its parameter effects. Research indicated the MEPDG provided comparable thickness to the 1993 AASHTO Guide if the failure criteria are set up reasonably. Therefore, the MEPDG could be used as a design tool to estimate layer thickness for FDR pavement with a low-medium traffic volume.

Performance Assessment of the Overall Building Envelope Thermal Performance-Building Envelope Performance(BEP)Metric

Today,to describe the thermal performance of the building envelope and its components we use a variation of metrics;such as,R-value,ACH(air exchange rate per hour),SHGC(solar heat gain coefficient)of windows,U-factor etc.None of these performance indicators is meant to represent the overall thermal performance.In this paper,such a metric is introduced,the BEP(building envelope performance)value.Unlike the thermal resistance,typically expressed as an R-value,the BEP-value considers additional elements of heat transfer that affect the energy demand of the building because of exterior and interior(solar)thermal loads:conductive and radiant heat transfer,and air infiltration.To demonstrate BEP’s utility,validation studies were carried out by comparing the BEP-value to theoretical results using whole building energy simulation tools such as EnergyPlus and WUFI Plus.Results show that BEP calculations are comparable to calculations made using these simulation tools and that unlike other similar metrics,the BEP-value accounts for all heat transfer mechanisms that are relevant for the overall energy performance of the building envelope.The BEP-value thus allows comparing envelopes of buildings with different use types in a fair and realistic manner.

Degradation Diagnostics from the Subsurface of Lithium-Ion Battery Electrodes

Despite the long-established rocking-chair theory of lithium-ion batteries(LIBs),developing novel characterization methodology with higher spatiotemporal resolution facilitates a better understanding of the solid electrolyte interphase studies to shape the reaction mechanisms.In this work,we develop a Xenon ion plasma focused ion beam(Xe+PFIB)-based characterization technique to probe the cross-sectional interface of both ternary cathode and graphite anode electrodes,with the focus on revealing the chemical composition and distribution underneath the electrode surface by in-depth analysis of secondary ions.Particularly,the lithium fluoride is detected in the pristine cathode prior to contact with the electrolyte,reflecting that the electrode degradation is in the form of the loss of lithium inventory during electrode preparation.This degradation is related to the hydrolysis of the cathode material and the decomposition of the PVDF binder.Through the quantitative analysis of the transition-metal degradation products,manganese is found to be the dominant element in the newly formed inactive fluoride deposition on the cathode,while no transition metal signal can be found inside the anode electrode.These insights at high resolution implemented via a PFIB-based characterization technique not only enrich the understanding of the degradation mechanism in the LIBs but also identify and enable a high-sensitivity methodology to obtain the chemical survey at the subsurface,which will help remove the capacity-fade observed in most LIBs.

Mechanistic modeling of copper corrosions in data center environments

Air-side economizers are increasingly used to take advantage of“free-cooling”in data centers with the intent of reducing the carbon footprint of buildings.However,they can introduce outdoor pollutants to indoor environment of data centers and cause corrosion damage to the information technology equipment.To evaluate the reliability of information technology equipment under various thermal and air-pollution conditions,a mechanistic model based on multi-ion transport and chemical reactions was developed.The model was used to predict Cu corrosion caused by Cl_(2)-containing pollutant mixtures.It also accounted for the effects of temperature(25℃and 28℃),relative humidity(50%,75%,and 95%),and synergism.It also identified higher air temperature as a corrosion barrier and higher relative humidity as a corrosion accelerator,which agreed well with the experimental results.The average root mean square error of the prediction was 13.7Å.The model can be used to evaluate the thermal guideline for data centers design and operation when Cl_(2)is present based on pre-established acceptable risk of corrosion in data centers’environment.

Bi-objective optimization models for mitigating traffic congestion in urban road networks

Traffic congestion in road transportation networks is a persistent problem in major metropolitan cities around the world.In this context,this paper deals with exploiting underutilized road capacities in a network to lower the congestion on overutilized links while simultaneously satisfying the system optimal flow assignment for sustainable transportation.Four congestion mitigation strategies are identified based on deviation and relative deviation of link volume from the corresponding capacity.Consequently,four biobjective mathematical programming optimal flow distribution(OFD)models are proposed.The case study results demonstrate that all the proposed models improve system performance and reduce congestion on high volume links by shifting flows to low volumeto-capacity links compared to UE and SO models.Among the models,the system optimality with minimal sum and maximum absolute relative-deviation models(SO-SAR and SO-MAR)showed superior results for different performance measures.The SO-SAR model yielded 50%and 30%fewer links at higher link utilization factors than UE and SO models,respectively.Also,it showed more than 25%improvement in path travel times compared to UE travel time for about 100 paths and resulted in the least network congestion index of1.04 compared to the other OFD and UE models.Conversely,the SO-MAR model yielded the least total distance and total system travel time,resulting in lower fuel consumption and emissions,thus contributing to sustainability.The proposed models contribute towards efficient transportation infrastructure management and will be of interest to transportation planners and traffic managers.

一种低密度耐高温高比强度多层次结构双相高熵合金

本文研究了一种新型低密度(~6.24 g cm^(-3))双相AlTiVCoNi高熵合金,其组织结构由有序L21高熵金属间化合物、无序体心立方结构和纳米L21相多层次结构构成.该合金在1200℃+24 h热处理下未发生相结构转变,在此条件下具有优异的高温相结构稳定性,其铸态和热处理态的压缩屈服强度相当,达到~1.6 GPa.另外,该合金在室温和600℃条件下表现出了优异的强塑性匹配和优异的比屈服强度,分别达到了约261和210 MPa g^(-1)cm^(3).该合金的超高强度主要源于有序L21相与体心立方相的半共格界面导致的一种强相结构稳定性和多层次结构的复合强化机制.该合金在800和1000℃压缩过程中出现了动态再结晶软化,使得其高温强度有所降低.这种“具有半共格界面L21+体心立方+纳米L21颗粒”的多层次结构设计为开发新型低密度耐高温高熵合金提供了一种新设计思路.

Polymer-coated nanoporous carbons for trace seawater uranium adsorption

Polymer-coated mesoporous carbon nanocomposites were prepared from the immobilization of acrylonitrile and acrylic acid copolymers with divinylbenzene as a crosslinker onto a mesoporous carbon framework.High surface areas were maintained after polymerization with accessible porosity.This functional nanocomposite was tested as an adsorbent for uranium from high salinity solutions.Uranium adsorption results have shown that the adsorption capacities are strongly influenced by the density of the amidoxime groups and the specific surface area.

Adsorption of rare earth ions using carbonized polydopamine nano carbon shells

Herein we reported the structure effects of carbon nano-shells prepared by the carbonization of polydopamine for the ad- sorption of rare earth elements （REEs） for the first time. Solid carbon spheres, 60 nm carbon shells and 500 nm carbon shells were prepared and evaluated for adsorption and desorption of REEs. The adsorption performance of carbon nano-shells for REEs was far superior to the solid carbon spheres. In addition, the effect of acidity on the adsorption and desorption properties was discussed. The good adsorption performance of the carbon nano-shells could be attributed to their pore structure, specific surface area, and the pres- ence of both amine and carbonyl groups from the grafted dopamine.

Hierarchical methodology to evaluate the quality of disparate axle load data sources for pavement design

Axle load data are an essential input for pavement design,yet for most North American agencies,there is uncertainty about the quality of axle load data obtained from weigh-inmotion(WIM)systems,the applicability of these data for pavement design,and potential opportunities to integrate axle load data from disparate sources.This article presents a novel and practical methodology to evaluate the quality of axle load data from WIM systems and roadside weigh scales through a series of hierarchical analyses designed to test data validity.When applied using data from Manitoba,Canada,the methodology quantified the uncertainty of axle loads measured at the weigh scales and piezo-quartz WIM,concluding that both could be used for pavement design applications.Data collected at piezo-polymer WIM sites exhibited poorer data validity;however,application of site-specific temperature correction factors significantly improved data validity at these sites.The article describes how other data quality dimensions,including spatial coverage,temporal coverage,and long-term data availability,could be considered when determining the suitability of disparate axle load data sources for pavement design.Application of the methodology enables a pragmatic evaluation of the quality and limitations of commonlyavailable axle load data,revealing uncertainties and data needs relevant for pavement design practice.

Atomic-scale tuned interface of nickel-rich cathode for enhanced electrochemical performance in lithium-ion batteries

The Ni-rich layered LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2)(NMC622)is one promising cathode for lithium-ion batteries(LIBs),but suffers from poor cycling stability under high cutoff potentials.The performance degradation was reflected as capacity fading and voltage drop,having their roots in instable interface of NMC622.Aimed at improving interfacial stability,in this study,we deposited nanoscale ZrO_(2) coatings conformally over NMC622 cathodes using atomic layer deposition(ALD).We found that,under a high cutoff voltage(4.5 V),the ALD ZrO_(2) coatings evidently improved the performance of NMC622 cathode,showing better cyclability and higher sustainable capacity.In addition,the ALD coatings dramatically boosted the rate capability of NMC622.All these compelling performance results are ascribed to the atomic-scale tunable ZrO_(2) coatings via ALD,which create stable interface and thereby inhibit unfavorable evolutions.In the study,we utilize a suite of characterization tools and various analyses to clarify the effects of ALD ZrO_(2) coatings.This study will be helpful for improving the performance of nickel-rich cathodes via interfacial engineering using ALD.

Spontaneous Imbibition of Water and Determination of Effective Contact Angles in the Eagle Ford Shale Formation Using Neutron Imaging

Understanding of fundamental processes and prediction of optimal parameters during the horizontal drilling and hydraulic fracturing process results in economically effective improvement of oil and natural gas extraction. Although modern analytical and computational models can capture fracture growth, there is a lack of experimental data on spontaneous imbibition and wettability in oil and gas reservoirs for the validation of further model development. In this work, we used neutron im- aging to measure the spontaneous imbibition of water into fractures of Eagle Ford shale with known geometries and fracture orientations. An analytical solution for a set of nonlinear second-order diffe- rential equations was applied to the measured imbibition data to determine effective contact angles. The analytical solution fit the measured imbibition data reasonably well and determined effective con- tact angles that were slightly higher than static contact angles due to effects of in-situ changes in veloci- ty, surface roughness, and heterogeneity of mineral surfaces on the fracture surface. Additionally, small fracture widths may have retarded imbibition and affected model fits, which suggests that aver- age fracture widths are not satisfactory for modeling imbibition in natural systems.