In situ recycling is one of the most effective methods to dispose of earth pressure balance(EPB)shield waste muck with residual foaming agents with high moisture content.In this context,response surface methodology(RS...In situ recycling is one of the most effective methods to dispose of earth pressure balance(EPB)shield waste muck with residual foaming agents with high moisture content.In this context,response surface methodology(RSM)was employed to quantify the effects of independent variables,including flocculant dosage,defoamer dosage,and muck drying mass(MDM)and their interactions on defoaming-flocculation-dewatering indices.The polymeric aluminum chloride(PACL)and hydroxy silicone oil-glycerol polypropylene ether(H-G)were selected as the flocculant and defoamer.The contents of surfactants and foam stabilizers in residual foaming agents were determined using the proposed empirical equation.The defoaming ratio,antifoaming ratio,turbidity,moisture content,filtration loss ratio,and fall cone penetration depth were considered as dependent variables.The accuracy of developed RSM models was verified by the analysis results of variance,residuals,and paired t-test.Combined with the desirability approach,an optimal mixing ratio of 0.078 wt%PACL,0.016 wt%H-G,and 27.882 wt%MDM was recommended,leading to a defoaming ratio of 98.34 vol%for residual foams and a moisture content of 56.72 wt%for pressure-filtration cakes.Our findings were demonstrated to be able to provide useful guidance for prediction and optimization of the in situ recycling indicators of EPB shield waste muck in metro tunnel construction sites.展开更多
The response of subsoil strata subjected to seismic excitations plays an important role in governing the response of the overlying superstructures at any site. Ground response analysis(GRA) helps to assess the influen...The response of subsoil strata subjected to seismic excitations plays an important role in governing the response of the overlying superstructures at any site. Ground response analysis(GRA) helps to assess the influence of soil characteristics on the propagating seismic stress waves from the bedrock level to the ground surface during an earthquake. For the northeastern region of India, located in the highest seismic zone in the country, conducting an extensive GRA study is of prime importance. Conventionally, most of the GRA studies are carried out using the equivalent linear method, which, being a simplistic approach, cannot capture the nonlinear behavior of soil during seismic shaking. This paper presents the outcomes of a one-dimensional effective stress based nonlinear GRA conducted for Guwahati city(located in northeast India) incorporating the non-Masing load/unload/reload characteristics. The various ground response parameters evaluated from this study help in assessing the ground shaking, soil amplification, and site responses expected in this region. 2D contour maps, which are representative of the distribution of some of these parameters throughout Guwahati city, are also developed. The results presented herein can serve as guidelines for the design of foundations and superstructures in this region.展开更多
This paper presents the effects of surface finish and treatment on the high cycle fatigue behaviour of vibrating cylinder block of a new two-stroke free piston engine at complex variable amplitude loading conditions u...This paper presents the effects of surface finish and treatment on the high cycle fatigue behaviour of vibrating cylinder block of a new two-stroke free piston engine at complex variable amplitude loading conditions using frequency response approach. Finite element modelling and frequency response analysis was conducted using finite element analysis software Package MSC.PATRAN/MSC.NASTRAN and fatigue life prediction was carded out using MSC.FATIGUE software. Based on the finite element results, different frequency response approach was applied to predict the cylinder block fatigue life. Results for different load histories and material combinations are also discussed. Results indicated great effects for all surface finish and treatment. It is concluded that polished and cast surface finish conditions give the highest and lowest cylinder block lives, respectively; and that Nitrided treatment leads to longest cylinder block life. The results were used to draw contour plots of fatigue life and damage in the worst or most damaging case.展开更多
L1 and L2 acquisition, in some respects, are similar. Language development in children goes hand in hand with physical and cognitive development. Children learn their first language by imitation, but not always and no...L1 and L2 acquisition, in some respects, are similar. Language development in children goes hand in hand with physical and cognitive development. Children learn their first language by imitation, but not always and not only by imitation. There seems to be some "innate capacities" that make children start to speak at the same time they do and in the way they do it. Adults learning a second language usually are controlled more by their motivation. But language input is important for both L1 and L2 acquisition. Though there are differences between CL1 and between CL2 and AL2, the way in which these learners acquire some of the grammatical morphemes is similar. This, together with some other evidence, shows that it is not only children who can acquire language. Adults can also acquire a language. But when adults acquire a language, they should also learn it. Some of the ways in which children acquire their language can be used as a model for L2 acquisition, even for Chinese students whose language is unrelated to English and whose culture is different. Learning the culture of the English-speaking countries will benefit the learning of the language. Like children, listening should also be well in advance of speaking in L2 acquisition. To train listening comprehension skills, Asher’s TPR approach proves more effective. TPR approach is at the moment limited to the beginning stage only. In order for students to gain all the five skills in a second language learning, namely, listening, speaking, reading, writing, and interpreting/translating, other methods should be used at the same time, or at later stages.展开更多
Accumulating evidence indicates that antibiotic exposure may lead to impaired vaccine responses1-4;however,the mechanisms underlying this association remain poorly understood.Here we prospectively followed 191 healthy...Accumulating evidence indicates that antibiotic exposure may lead to impaired vaccine responses1-4;however,the mechanisms underlying this association remain poorly understood.Here we prospectively followed 191 healthy,vaginally born,term infants from birth to 15 months,using a systems vaccinology approach to assess the effects of antibiotic exposure on immune responses to vaccination.Exposure to direct neonatal but not intrapartum antibiotics was associated with significantly lower antibody titres against various polysaccharides in the 13-valent pneumococcal conjugate vaccine and the Haemophilus influenzae type b polyribosylribitol phosphate and diphtheria toxoid antigens in the combined 6-in-1 Infanrix Hexa vaccine at 7 months of age.Blood from infants exposed to neonatal antibiotics had an inflammatory transcriptional profile before vaccination;in addition,faecal metagenomics showed reduced abundance of Bifidobacterium species in these infants at the time of vaccination,which was correlated with reduced vaccine antibody titres 6 months later.In preclinical models,responses to the 13-valent pneumococcal conjugate vaccine were strongly dependent on an intact microbiota but could be restored in germ-free mice by administering a consortium of Bifidobacterium species or a probiotic already widely used in neonatal units.Our data suggest that microbiota-targeted interventions could mitigate the detrimental effects of early-life antibiotics on vaccine immunogenicity.展开更多
4 semi-analytical approach for the dynamic response of general thin plates whichemployes finite element discretization in space domain and a series of representation intime demain is developed on the basis of Curtin v...4 semi-analytical approach for the dynamic response of general thin plates whichemployes finite element discretization in space domain and a series of representation intime demain is developed on the basis of Curtin variational principles.The formulationof time series is also investigated so that the dynamic response of plates with arbitraryshape and boundary constraints can be achieved with adequate accuracy.展开更多
A number of methods and approaches have been practiced in recent communicative language teaching,the applying of the reader-response approach has seen the effectiveness in the EFL literature classes.Learner autonomy i...A number of methods and approaches have been practiced in recent communicative language teaching,the applying of the reader-response approach has seen the effectiveness in the EFL literature classes.Learner autonomy in EFL literature classes is reader’s ability to regard the reading text as his/her own both in the act of reading and after the act of reading.展开更多
Objective: To study the muscle injury, inflammatory response and bone metabolism after paravertebral muscle space and minimally invasive percutaneous approach surgeries for thoracolumbar fracture. Methods: A total of ...Objective: To study the muscle injury, inflammatory response and bone metabolism after paravertebral muscle space and minimally invasive percutaneous approach surgeries for thoracolumbar fracture. Methods: A total of 92 patients with thoracolumbar fractures who were treated in Baoji Central Hospital between May 2015 and January 2017 were selected and randomly divided into paravertebral group and minimally invasive percutaneous group who accepted pedicle screw fixation under different approaches. Before operation as well as 1 d and 3 d after operation, serum was collected to determine the contents of creatase, inflammatory reaction molecules and bone metabolism indexes. Results: Serum Myo, CK, LDH, TNF-α, MCP-1, HMGB-1, CRP, IL-1β, OC, OPG, PICP and PINP levels of both groups 1 d and 3 d after operation were significantly higher than those before operation while TRACP5b, RANKL, CTX and NTX levels were significantly lower than those before operation, and serum Myo, CK, LDH, TNF-α, MCP-1, HMGB-1, CRP, IL-1β, TRACP5b, RANKL, CTX and NTX levels of paravertebral group 1 d and 3 d after operation were significantly lower than those of minimally invasive percutaneous group while OC, OPG, PICP and PINP levels were significantly higher than those of minimally invasive percutaneous group. Conclusion:Paravertebral muscle space surgery for thoracolumbar fracture is more effective than minimally invasive percutaneous surgery in reducing muscle injury and inflammatory response, and improving bone metabolism.展开更多
The probabilistic damage identification problem with uncertainty in the FE model parameters, external-excitations and measured acceleration responses is studied. The uncertainty in the system is concerned with normall...The probabilistic damage identification problem with uncertainty in the FE model parameters, external-excitations and measured acceleration responses is studied. The uncertainty in the system is concerned with normally distributed random variables with zero mean value and given covariance. Based on the theoretical model and the measured acceleration responses, the probabilistic structural models in undamaged and damaged states are obtained by two-stage model updating, and then the Probabilities of Damage Existence （PDE） of each element are calculated as the damage criterion. The influences of the location of sensors on the damage identification results are also discussed, where one of the optimal sensor placement techniques, the effective independence method, is used to choose the nodes for measurement. The damage identification results by different numbers of measured nodes and different damage criterions are compared in the numerical example.展开更多
Considering the requirement of direct design and fatigue test for ships and floating structures by use of FEM technique, a computational procedure of spectral analysis for wave load on the hull surface is developed in...Considering the requirement of direct design and fatigue test for ships and floating structures by use of FEM technique, a computational procedure of spectral analysis for wave load on the hull surface is developed in this paper. The response of hydrodynamic pressure on the body surface to a designated sea state for ships and floating structures is calculated by use of the revised strip method with the hull bound perturbation flow concept. The spectral function of wave load for the defined point on the body surface can be determined from the Wiener-Khinhine theorem and the characteristic load value can be also obtained from spectral moment analysis. A container ship is taken as a computational example acid the sample of wave load with a certain probability and corresponding encountered frequency is provided.展开更多
The two-dimensional transient response of an imperfect bonded circular lined pipeline lying in an elastic infinite medium is investigated.Imperfect boundary conditions between the surrounding elastic rock and the tunn...The two-dimensional transient response of an imperfect bonded circular lined pipeline lying in an elastic infinite medium is investigated.Imperfect boundary conditions between the surrounding elastic rock and the tunnel are modelled with a two-linear-spring design.The novelty of the manuscript consists in studying at the same time transient regimes and imperfect bonded interfaces for simulating the dynamic response of a tunnel embedded in an elastic infinite rock.Wave propagation fields in tunnel and rock are expressed in terms of infinite Bessel and Hankel series.To solve the transient problem,the Laplace transform and the associated Durbin’s algorithm are performed.To exhibit the dynamic responses,influences of various parameters such as the quality of the interface conditions and the thickness of the lining are presented.The dynamic hoop stresses and the solid displacements of both the tunnel and the rock are also proposed.展开更多
It is pointed out that the damping matrix deduced by active members in the finite element vibration equation of a truss adaptive structure generally can not be decoupled, which leads to the difficulty in the process o...It is pointed out that the damping matrix deduced by active members in the finite element vibration equation of a truss adaptive structure generally can not be decoupled, which leads to the difficulty in the process of modal analysis by classical superposition method. This paper focuses on the computational method of the dynamic response for truss adaptive structures. Firstly, a new technique of state vector approach is applied to study the dynamic response of truss adaptive structures. It can make the coeffic lent matrix of first derivative of state vector a symmetric positive definite matrix, and particularly a diagonal matrix provided that mass matrix is derived by lumped method, so the coefficient matrix of the first derivative of state vector can be exactly decomposed by CHOLESKY method. In this case, the proposed technique not only improves the calculation accuracy, but also saves the computing time. Based on the procedure mentioned above, the mathematical formulation for the system response of truss adaptive structures is systematically derived in theory. Thirdly, by using FORTRAN language, a program system for computing dynamic response of truss adaptive structures is developed. Fourthly, a typical 18 bar space truss adaptive structure has been chosen as test numerical examples to show the feasibility and effectiveness of the proposed method. Finally, some good suggestions, such as how to choose complex mode shapes practically in determining the dynamic response are also given. The new approach can be extended to calculate the dynamic response of general adaptive structures.展开更多
The global pandemic caused by the coronavirus disease 2019 not only exposed the fragility of global preparedness and response to public health emergence,but also illustrated the fragmentation and gaps of research and ...The global pandemic caused by the coronavirus disease 2019 not only exposed the fragility of global preparedness and response to public health emergence,but also illustrated the fragmentation and gaps of research and development ecosystem.This emphasizes the need for planned actions against the potentiality of new pandemics and requires research to better understand how viruses bridge the animal/human divide making human-to-human transmission of new diseases possible.Major challenges to response to new epidemics under the current health framework reside in the so called 4-CC approach that focuses on Concept,Communication,Coherence,and Continuity.There is a need to also add a One Health perspective with emphasis on governance,surveillance,capacity building and multi-disciplinary research to achieve a holistic and better integrated system.Using a regulatory framework to equip professionals might facilitate the function of a multi-sector approach that recognizes the value of their mandates and a One Health approach in their work.Collaborative,multisectoral actions under the global regulations and guidance would make evidence-based One Health approaches sustainable and accessible to everyone.展开更多
Background： Adaptive response includes a variety of physiological modifications to face changes in external or internal conditions and adapt to a new situation. The acute phase proteins（APPs） are reactants synthesi...Background： Adaptive response includes a variety of physiological modifications to face changes in external or internal conditions and adapt to a new situation. The acute phase proteins（APPs） are reactants synthesized against environmental stimuli like stress, infection, inflammation.Methods： To delineate the differences in molecular constituents of adaptive response to the environment we performed the whole-blood transcriptome analysis in Italian Holstein（IH） and Italian Simmental（IS） breeds. For this, 663 IH and IS cows from six commercial farms were clustered according to the blood level of APPs. Ten extreme individuals（five APP＋ and APP-variants） from each farm were selected for the RNA-seq using the Illumina sequencing technology. Differentially expressed（DE） genes were analyzed using dynamic impact approach（DIA）and DAVID annotation clustering. Milk production data were statistically elaborated to assess the association of APP＋ and APP-gene expression patterns with variations in milk parameters.Results： The overall de novo assembly of cDNA sequence data generated 13,665 genes expressed in bovine blood cells. Comparative genomic analysis revealed 1,152 DE genes in the comparison of all APP＋ vs. all APP-variants; 531 and 217 DE genes specific for IH and IS comparison respectively. In all comparisons overexpressed genes were more represented than underexpressed ones. DAVID analysis revealed 369 DE genes across breeds, 173 and 73 DE genes in IH and IS comparison respectively. Among the most impacted pathways for both breeds were vitamin B6 metabolism, folate biosynthesis, nitrogen metabolism and linoleic acid metabolism.Conclusions： Both DIA and DAVID approaches produced a high number of significantly impacted genes and pathways with a narrow connection to adaptive response in cows with high level of blood APPs. A similar variation in gene expression and impacted pathways between APP＋ and APP-variants was found between two studied breeds. Such similarity was also confirmed by annotation clustering of the DE genes. However, IH breed showed higher and more differentiated impacts compared to IS breed and such particular features in the IH adaptive response could be explained by its higher metabolic activity. Variations of milk production data were significantly associated with APP＋ and APP-gene expression patterns.展开更多
Response surface methodology (RSM) based on desirability function approach (DFA) is applied to obtain an optimal design of the impeller geometry for an automotive torque converter. <span style="font-family:Ver...Response surface methodology (RSM) based on desirability function approach (DFA) is applied to obtain an optimal design of the impeller geometry for an automotive torque converter. <span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">The relative importance of six design parameters including impeller blade number, blade thickness, bias angle, scroll angle, inlet angle and exit angle is investigated using orthogonal design approach. </span></span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">The impeller inlet angle, exit angle and bias angle </span><span style="font-family:Verdana;">are found to exert the greatest influence on the overall performance of a torque converter, with two flow area factors being considered, namely 17% and 20%. Then, RSM together with central composite design (CCD) method is used to in-depth evaluate the interaction effect of the three key parameters on converter performance. The results demonstrate that </span><span style="font-family:Verdana;">impeller exit angle has the strongest impact on peak efficiency</span><span style="font-family:Verdana;">, with larger angles yielding the most favorable results. The stall torque ratio maximization is attainable with the increase of impeller bias angle and inlet angle together with smaller exit angle. In the end, </span><span style="font-family:Verdana;">an optimized design for the impeller geometry is obtained with stall torque ratio and peak efficiency increased by 1.62% and 1.1%, respectively.</span><span style="font-family:Verdana;"> The new optimization method can be used as a reference for performance enhancement in the design process of impeller geometry for an automotive torque converter.</span></span></span></span>展开更多
Individuals,local communities,environmental associations,private organizations,and public representatives and bodies may all be aggrieved by environmental problems concerning poor air quality,illegal waste disposal,wa...Individuals,local communities,environmental associations,private organizations,and public representatives and bodies may all be aggrieved by environmental problems concerning poor air quality,illegal waste disposal,water contamination,and general pollution.Environmental complaints represent the expressions of dissatisfaction with these issues.As the timeconsuming of managing a large number of complaints,text mining may be useful for automatically extracting information on stakeholder priorities and concerns.The paper used text mining and semantic network analysis to crawl relevant keywords about environmental complaints from two online complaint submission systems:online claim submission system of Regional Agency for Prevention,Environment and Energy(Arpae)(“Contact Arpae”);and Arpae's internal platform for environmental pollution(“Environmental incident reporting portal”)in the Emilia-Romagna Region,Italy.We evaluated the total of 2477 records and classified this information based on the claim topic(air pollution,water pollution,noise pollution,waste,odor,soil,weather-climate,sea-coast,and electromagnetic radiation)and geographical distribution.Then,this paper used natural language processing to extract keywords from the dataset,and classified keywords ranking higher in Term Frequency-Inverse Document Frequency(TF-IDF)based on the driver,pressure,state,impact,and response(DPSIR)framework.This study provided a systemic approach to understanding the interaction between people and environment in different geographical contexts and builds sustainable and healthy communities.The results showed that most complaints are from the public and associated with air pollution and odor.Factories(particularly foundries and ceramic industries)and farms are identified as the drivers of environmental issues.Citizen believed that environmental issues mainly affect human well-being.Moreover,the keywords of“odor”,“report”,“request”,“presence”,“municipality”,and“hours”were the most influential and meaningful concepts,as demonstrated by their high degree and betweenness centrality values.Keywords connecting odor(classified as impacts)and air pollution(classified as state)were the most important(such as“odor-burnt plastic”and“odor-acrid”).Complainants perceived odor annoyance as a primary environmental concern,possibly related to two main drivers:“odor-factory”and“odorsfarms”.The proposed approach has several theoretical and practical implications:text mining may quickly and efficiently address citizen needs,providing the basis toward automating(even partially)the complaint process;and the DPSIR framework might support the planning and organization of information and the identification of stakeholder concerns and priorities,as well as metrics and indicators for their assessment.Therefore,integration of the DPSIR framework with the text mining of environmental complaints might generate a comprehensive environmental knowledge base as a prerequisite for a wider exploitation of analysis to support decision-making processes and environmental management activities.展开更多
On the power supply side,renewable energy(RE)is an important substitute to traditional energy,the effective utilization of which has become one of the major challenges in risk-constrained power system operations.This ...On the power supply side,renewable energy(RE)is an important substitute to traditional energy,the effective utilization of which has become one of the major challenges in risk-constrained power system operations.This paper proposes a risk-based power dispatching strategy considering the demand response(DR)and RE utilization in the stochastic optimal scheduling of parallel manufacturing process(PMP)in industrial manufacturing enterprises(IME).First,the specific production behavior model of PMP is formulated to characterize the flexibility of power demand.Then,a two-step strategic model is proposed to comprehensively quantify multiple factors in the optimal scheduling of DR in PMP loads considering risk-based power system dispatch,thermal generators,wind power integration.Case studies are based on the modified IEEE 24-bus power system,which verify the effectiveness of the proposed strategy in optimally coordinating IME assets with generation resources for promoting the RE utilization,as well as the impacts of power transmission risk on decision performance.展开更多
Renewable energy sources(RES)have strong uncertainties,which significantly increase the risks of power imbalance and load shedding in composite power systems.It is thus necessary to evaluate the operational reliabilit...Renewable energy sources(RES)have strong uncertainties,which significantly increase the risks of power imbalance and load shedding in composite power systems.It is thus necessary to evaluate the operational reliability for guiding economic dispatch and reducing the risks.Current methods cannot meet the requirement for the operational timeliness of reliability evaluations due to the high computa-tional complexity of the optimal power flow(OPF)calculations of massive contingencies.This paper pro-poses a fully analytical approach to construct fast-to-run analytical functions of reliability indices and avoid reassessments when the load and RES change.The approach consists of uniform design(UD)-based contingency screening and a modified stochastic response surface method(mSRSM).The contin-gency screening method is used to select critical contingencies while considering the uncertainties.The mSRSM is used to construct the analytical functions of the load shedding to the load and RES gener-ation for the selected contingencies.An analytical function of a smooth virtual variable that maps to the load shedding is established in such a way that,when the load and RES vary,the reliability can be assessed within a very short time rather than using laborious OPF calculations.Case studies illustrate the excellent performance of the proposed method for real-time reliability evaluation.展开更多
In this paper,the isogeometric analysis(IGA)method is employed to analyze the oscillation characteristics of functionally graded triply periodic minimal surface(FG-TPMS)curved-doubly shells integrated with magneto-ele...In this paper,the isogeometric analysis(IGA)method is employed to analyze the oscillation characteristics of functionally graded triply periodic minimal surface(FG-TPMS)curved-doubly shells integrated with magneto-electric surface layers(referred to as"FG-TPMS-MEE curved-doubly shells")subjected to low-velocity impact loads.This study presents low-velocity impact load model based on a single springmass(S-M)approach.The FG-TPMS-MEE curved-doubly shells are covered with two magneto-electric surface layers,while the core layer consists of three types:I-graph and Wrapped Package-graph(IWP),Gyroid(G),and Primitive(P),with various graded functions.These types are notable for their exceptional stiffness-to-weight ratios,enabling a wide range of potential applications.The Maxwell equations and electromagnetic boundary conditions are applied to compute the change in electric potentials and magnetic potentials.The equilibrium equations of the shell are derived from a refined higher-order shear deformation theory(HSDT),and the transient responses of the FG-TPMS-MEE curveddoubly shells are subsequently determined using Newmark's direct integration method.These results have applications in structural vibration control and the analysis of structures subjected to impact or explosive loads.Furthermore,this study provides a theoretical prediction of the low-velocity impact load and magneto-electric-elastic effects on the free vibration and transient response of FG-TPMS-MEE curved-doubly shells.展开更多
Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity ana...Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity analysis of hydrological model is a key step in model uncertainty quantification, which can identify the dominant parameters, reduce the model calibration uncertainty, and enhance the model optimization efficiency. There are, however, some shortcomings in classical approaches, including the long duration of time and high computation cost required to quantitatively assess the sensitivity of a multiple-parameter hydrological model. For this reason, a two-step statistical evaluation framework using global techniques is presented. It is based on （1） a screening method （Morris） for qualitative ranking of parameters, and （2） a variance-based method integrated with a meta-model for quantitative sensitivity analysis, i.e., the Sobol method integrated with the response surface model （RSMSobol）. First, the Morris screening method was used to qualitatively identify the parameters＇ sensitivity, and then ten parameters were selected to quantify the sensitivity indices. Subsequently, the RSMSobol method was used to quantify the sensitivity, i.e., the first-order and total sensitivity indices based on the response surface model （RSM） were calculated. The RSMSobol method can not only quantify the sensitivity, but also reduce the computational cost, with good accuracy compared to the classical approaches. This approach will be effective and reliable in the global sensitivity analysis of a complex large-scale distributed hydrological model.展开更多
基金supported by the National Youth Top-notch Talent Support Program of China(Grant No.00389335)the National Natural Science Foundation of China(Grant No.52378392)the“Foal Eagle Program”Youth Top-notch Talent Project of Fujian Province(Grant No.00387088).
文摘In situ recycling is one of the most effective methods to dispose of earth pressure balance(EPB)shield waste muck with residual foaming agents with high moisture content.In this context,response surface methodology(RSM)was employed to quantify the effects of independent variables,including flocculant dosage,defoamer dosage,and muck drying mass(MDM)and their interactions on defoaming-flocculation-dewatering indices.The polymeric aluminum chloride(PACL)and hydroxy silicone oil-glycerol polypropylene ether(H-G)were selected as the flocculant and defoamer.The contents of surfactants and foam stabilizers in residual foaming agents were determined using the proposed empirical equation.The defoaming ratio,antifoaming ratio,turbidity,moisture content,filtration loss ratio,and fall cone penetration depth were considered as dependent variables.The accuracy of developed RSM models was verified by the analysis results of variance,residuals,and paired t-test.Combined with the desirability approach,an optimal mixing ratio of 0.078 wt%PACL,0.016 wt%H-G,and 27.882 wt%MDM was recommended,leading to a defoaming ratio of 98.34 vol%for residual foams and a moisture content of 56.72 wt%for pressure-filtration cakes.Our findings were demonstrated to be able to provide useful guidance for prediction and optimization of the in situ recycling indicators of EPB shield waste muck in metro tunnel construction sites.
文摘The response of subsoil strata subjected to seismic excitations plays an important role in governing the response of the overlying superstructures at any site. Ground response analysis(GRA) helps to assess the influence of soil characteristics on the propagating seismic stress waves from the bedrock level to the ground surface during an earthquake. For the northeastern region of India, located in the highest seismic zone in the country, conducting an extensive GRA study is of prime importance. Conventionally, most of the GRA studies are carried out using the equivalent linear method, which, being a simplistic approach, cannot capture the nonlinear behavior of soil during seismic shaking. This paper presents the outcomes of a one-dimensional effective stress based nonlinear GRA conducted for Guwahati city(located in northeast India) incorporating the non-Masing load/unload/reload characteristics. The various ground response parameters evaluated from this study help in assessing the ground shaking, soil amplification, and site responses expected in this region. 2D contour maps, which are representative of the distribution of some of these parameters throughout Guwahati city, are also developed. The results presented herein can serve as guidelines for the design of foundations and superstructures in this region.
基金Project (No. 03-02-02-0056 PR0025/04-03) supported by Ministry of Science, Technology and Innovation, Malaysia
文摘This paper presents the effects of surface finish and treatment on the high cycle fatigue behaviour of vibrating cylinder block of a new two-stroke free piston engine at complex variable amplitude loading conditions using frequency response approach. Finite element modelling and frequency response analysis was conducted using finite element analysis software Package MSC.PATRAN/MSC.NASTRAN and fatigue life prediction was carded out using MSC.FATIGUE software. Based on the finite element results, different frequency response approach was applied to predict the cylinder block fatigue life. Results for different load histories and material combinations are also discussed. Results indicated great effects for all surface finish and treatment. It is concluded that polished and cast surface finish conditions give the highest and lowest cylinder block lives, respectively; and that Nitrided treatment leads to longest cylinder block life. The results were used to draw contour plots of fatigue life and damage in the worst or most damaging case.
文摘L1 and L2 acquisition, in some respects, are similar. Language development in children goes hand in hand with physical and cognitive development. Children learn their first language by imitation, but not always and not only by imitation. There seems to be some "innate capacities" that make children start to speak at the same time they do and in the way they do it. Adults learning a second language usually are controlled more by their motivation. But language input is important for both L1 and L2 acquisition. Though there are differences between CL1 and between CL2 and AL2, the way in which these learners acquire some of the grammatical morphemes is similar. This, together with some other evidence, shows that it is not only children who can acquire language. Adults can also acquire a language. But when adults acquire a language, they should also learn it. Some of the ways in which children acquire their language can be used as a model for L2 acquisition, even for Chinese students whose language is unrelated to English and whose culture is different. Learning the culture of the English-speaking countries will benefit the learning of the language. Like children, listening should also be well in advance of speaking in L2 acquisition. To train listening comprehension skills, Asher’s TPR approach proves more effective. TPR approach is at the moment limited to the beginning stage only. In order for students to gain all the five skills in a second language learning, namely, listening, speaking, reading, writing, and interpreting/translating, other methods should be used at the same time, or at later stages.
文摘Accumulating evidence indicates that antibiotic exposure may lead to impaired vaccine responses1-4;however,the mechanisms underlying this association remain poorly understood.Here we prospectively followed 191 healthy,vaginally born,term infants from birth to 15 months,using a systems vaccinology approach to assess the effects of antibiotic exposure on immune responses to vaccination.Exposure to direct neonatal but not intrapartum antibiotics was associated with significantly lower antibody titres against various polysaccharides in the 13-valent pneumococcal conjugate vaccine and the Haemophilus influenzae type b polyribosylribitol phosphate and diphtheria toxoid antigens in the combined 6-in-1 Infanrix Hexa vaccine at 7 months of age.Blood from infants exposed to neonatal antibiotics had an inflammatory transcriptional profile before vaccination;in addition,faecal metagenomics showed reduced abundance of Bifidobacterium species in these infants at the time of vaccination,which was correlated with reduced vaccine antibody titres 6 months later.In preclinical models,responses to the 13-valent pneumococcal conjugate vaccine were strongly dependent on an intact microbiota but could be restored in germ-free mice by administering a consortium of Bifidobacterium species or a probiotic already widely used in neonatal units.Our data suggest that microbiota-targeted interventions could mitigate the detrimental effects of early-life antibiotics on vaccine immunogenicity.
文摘4 semi-analytical approach for the dynamic response of general thin plates whichemployes finite element discretization in space domain and a series of representation intime demain is developed on the basis of Curtin variational principles.The formulationof time series is also investigated so that the dynamic response of plates with arbitraryshape and boundary constraints can be achieved with adequate accuracy.
文摘A number of methods and approaches have been practiced in recent communicative language teaching,the applying of the reader-response approach has seen the effectiveness in the EFL literature classes.Learner autonomy in EFL literature classes is reader’s ability to regard the reading text as his/her own both in the act of reading and after the act of reading.
文摘Objective: To study the muscle injury, inflammatory response and bone metabolism after paravertebral muscle space and minimally invasive percutaneous approach surgeries for thoracolumbar fracture. Methods: A total of 92 patients with thoracolumbar fractures who were treated in Baoji Central Hospital between May 2015 and January 2017 were selected and randomly divided into paravertebral group and minimally invasive percutaneous group who accepted pedicle screw fixation under different approaches. Before operation as well as 1 d and 3 d after operation, serum was collected to determine the contents of creatase, inflammatory reaction molecules and bone metabolism indexes. Results: Serum Myo, CK, LDH, TNF-α, MCP-1, HMGB-1, CRP, IL-1β, OC, OPG, PICP and PINP levels of both groups 1 d and 3 d after operation were significantly higher than those before operation while TRACP5b, RANKL, CTX and NTX levels were significantly lower than those before operation, and serum Myo, CK, LDH, TNF-α, MCP-1, HMGB-1, CRP, IL-1β, TRACP5b, RANKL, CTX and NTX levels of paravertebral group 1 d and 3 d after operation were significantly lower than those of minimally invasive percutaneous group while OC, OPG, PICP and PINP levels were significantly higher than those of minimally invasive percutaneous group. Conclusion:Paravertebral muscle space surgery for thoracolumbar fracture is more effective than minimally invasive percutaneous surgery in reducing muscle injury and inflammatory response, and improving bone metabolism.
基金Project supported by the National Nature Science Foundation of China(No.11372025)the Aeronautical Science Foundation of China(No.2012ZA51010)Defense Industrial Technology Development Program(Nos.A2120110001 and B2120110011)
文摘The probabilistic damage identification problem with uncertainty in the FE model parameters, external-excitations and measured acceleration responses is studied. The uncertainty in the system is concerned with normally distributed random variables with zero mean value and given covariance. Based on the theoretical model and the measured acceleration responses, the probabilistic structural models in undamaged and damaged states are obtained by two-stage model updating, and then the Probabilities of Damage Existence （PDE） of each element are calculated as the damage criterion. The influences of the location of sensors on the damage identification results are also discussed, where one of the optimal sensor placement techniques, the effective independence method, is used to choose the nodes for measurement. The damage identification results by different numbers of measured nodes and different damage criterions are compared in the numerical example.
文摘Considering the requirement of direct design and fatigue test for ships and floating structures by use of FEM technique, a computational procedure of spectral analysis for wave load on the hull surface is developed in this paper. The response of hydrodynamic pressure on the body surface to a designated sea state for ships and floating structures is calculated by use of the revised strip method with the hull bound perturbation flow concept. The spectral function of wave load for the defined point on the body surface can be determined from the Wiener-Khinhine theorem and the characteristic load value can be also obtained from spectral moment analysis. A container ship is taken as a computational example acid the sample of wave load with a certain probability and corresponding encountered frequency is provided.
文摘The two-dimensional transient response of an imperfect bonded circular lined pipeline lying in an elastic infinite medium is investigated.Imperfect boundary conditions between the surrounding elastic rock and the tunnel are modelled with a two-linear-spring design.The novelty of the manuscript consists in studying at the same time transient regimes and imperfect bonded interfaces for simulating the dynamic response of a tunnel embedded in an elastic infinite rock.Wave propagation fields in tunnel and rock are expressed in terms of infinite Bessel and Hankel series.To solve the transient problem,the Laplace transform and the associated Durbin’s algorithm are performed.To exhibit the dynamic responses,influences of various parameters such as the quality of the interface conditions and the thickness of the lining are presented.The dynamic hoop stresses and the solid displacements of both the tunnel and the rock are also proposed.
基金supported by National Natural Science Foundation of China (Grant No. 10472007)
文摘It is pointed out that the damping matrix deduced by active members in the finite element vibration equation of a truss adaptive structure generally can not be decoupled, which leads to the difficulty in the process of modal analysis by classical superposition method. This paper focuses on the computational method of the dynamic response for truss adaptive structures. Firstly, a new technique of state vector approach is applied to study the dynamic response of truss adaptive structures. It can make the coeffic lent matrix of first derivative of state vector a symmetric positive definite matrix, and particularly a diagonal matrix provided that mass matrix is derived by lumped method, so the coefficient matrix of the first derivative of state vector can be exactly decomposed by CHOLESKY method. In this case, the proposed technique not only improves the calculation accuracy, but also saves the computing time. Based on the procedure mentioned above, the mathematical formulation for the system response of truss adaptive structures is systematically derived in theory. Thirdly, by using FORTRAN language, a program system for computing dynamic response of truss adaptive structures is developed. Fourthly, a typical 18 bar space truss adaptive structure has been chosen as test numerical examples to show the feasibility and effectiveness of the proposed method. Finally, some good suggestions, such as how to choose complex mode shapes practically in determining the dynamic response are also given. The new approach can be extended to calculate the dynamic response of general adaptive structures.
基金supported by the Excellence Action Plan for Science and Technology Journals in China(C-084)。
文摘The global pandemic caused by the coronavirus disease 2019 not only exposed the fragility of global preparedness and response to public health emergence,but also illustrated the fragmentation and gaps of research and development ecosystem.This emphasizes the need for planned actions against the potentiality of new pandemics and requires research to better understand how viruses bridge the animal/human divide making human-to-human transmission of new diseases possible.Major challenges to response to new epidemics under the current health framework reside in the so called 4-CC approach that focuses on Concept,Communication,Coherence,and Continuity.There is a need to also add a One Health perspective with emphasis on governance,surveillance,capacity building and multi-disciplinary research to achieve a holistic and better integrated system.Using a regulatory framework to equip professionals might facilitate the function of a multi-sector approach that recognizes the value of their mandates and a One Health approach in their work.Collaborative,multisectoral actions under the global regulations and guidance would make evidence-based One Health approaches sustainable and accessible to everyone.
基金funded by the Italian Ministry of Education,University and Research(PRIN GEN2PHEN)
文摘Background： Adaptive response includes a variety of physiological modifications to face changes in external or internal conditions and adapt to a new situation. The acute phase proteins（APPs） are reactants synthesized against environmental stimuli like stress, infection, inflammation.Methods： To delineate the differences in molecular constituents of adaptive response to the environment we performed the whole-blood transcriptome analysis in Italian Holstein（IH） and Italian Simmental（IS） breeds. For this, 663 IH and IS cows from six commercial farms were clustered according to the blood level of APPs. Ten extreme individuals（five APP＋ and APP-variants） from each farm were selected for the RNA-seq using the Illumina sequencing technology. Differentially expressed（DE） genes were analyzed using dynamic impact approach（DIA）and DAVID annotation clustering. Milk production data were statistically elaborated to assess the association of APP＋ and APP-gene expression patterns with variations in milk parameters.Results： The overall de novo assembly of cDNA sequence data generated 13,665 genes expressed in bovine blood cells. Comparative genomic analysis revealed 1,152 DE genes in the comparison of all APP＋ vs. all APP-variants; 531 and 217 DE genes specific for IH and IS comparison respectively. In all comparisons overexpressed genes were more represented than underexpressed ones. DAVID analysis revealed 369 DE genes across breeds, 173 and 73 DE genes in IH and IS comparison respectively. Among the most impacted pathways for both breeds were vitamin B6 metabolism, folate biosynthesis, nitrogen metabolism and linoleic acid metabolism.Conclusions： Both DIA and DAVID approaches produced a high number of significantly impacted genes and pathways with a narrow connection to adaptive response in cows with high level of blood APPs. A similar variation in gene expression and impacted pathways between APP＋ and APP-variants was found between two studied breeds. Such similarity was also confirmed by annotation clustering of the DE genes. However, IH breed showed higher and more differentiated impacts compared to IS breed and such particular features in the IH adaptive response could be explained by its higher metabolic activity. Variations of milk production data were significantly associated with APP＋ and APP-gene expression patterns.
文摘Response surface methodology (RSM) based on desirability function approach (DFA) is applied to obtain an optimal design of the impeller geometry for an automotive torque converter. <span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">The relative importance of six design parameters including impeller blade number, blade thickness, bias angle, scroll angle, inlet angle and exit angle is investigated using orthogonal design approach. </span></span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">The impeller inlet angle, exit angle and bias angle </span><span style="font-family:Verdana;">are found to exert the greatest influence on the overall performance of a torque converter, with two flow area factors being considered, namely 17% and 20%. Then, RSM together with central composite design (CCD) method is used to in-depth evaluate the interaction effect of the three key parameters on converter performance. The results demonstrate that </span><span style="font-family:Verdana;">impeller exit angle has the strongest impact on peak efficiency</span><span style="font-family:Verdana;">, with larger angles yielding the most favorable results. The stall torque ratio maximization is attainable with the increase of impeller bias angle and inlet angle together with smaller exit angle. In the end, </span><span style="font-family:Verdana;">an optimized design for the impeller geometry is obtained with stall torque ratio and peak efficiency increased by 1.62% and 1.1%, respectively.</span><span style="font-family:Verdana;"> The new optimization method can be used as a reference for performance enhancement in the design process of impeller geometry for an automotive torque converter.</span></span></span></span>
文摘Individuals,local communities,environmental associations,private organizations,and public representatives and bodies may all be aggrieved by environmental problems concerning poor air quality,illegal waste disposal,water contamination,and general pollution.Environmental complaints represent the expressions of dissatisfaction with these issues.As the timeconsuming of managing a large number of complaints,text mining may be useful for automatically extracting information on stakeholder priorities and concerns.The paper used text mining and semantic network analysis to crawl relevant keywords about environmental complaints from two online complaint submission systems:online claim submission system of Regional Agency for Prevention,Environment and Energy(Arpae)(“Contact Arpae”);and Arpae's internal platform for environmental pollution(“Environmental incident reporting portal”)in the Emilia-Romagna Region,Italy.We evaluated the total of 2477 records and classified this information based on the claim topic(air pollution,water pollution,noise pollution,waste,odor,soil,weather-climate,sea-coast,and electromagnetic radiation)and geographical distribution.Then,this paper used natural language processing to extract keywords from the dataset,and classified keywords ranking higher in Term Frequency-Inverse Document Frequency(TF-IDF)based on the driver,pressure,state,impact,and response(DPSIR)framework.This study provided a systemic approach to understanding the interaction between people and environment in different geographical contexts and builds sustainable and healthy communities.The results showed that most complaints are from the public and associated with air pollution and odor.Factories(particularly foundries and ceramic industries)and farms are identified as the drivers of environmental issues.Citizen believed that environmental issues mainly affect human well-being.Moreover,the keywords of“odor”,“report”,“request”,“presence”,“municipality”,and“hours”were the most influential and meaningful concepts,as demonstrated by their high degree and betweenness centrality values.Keywords connecting odor(classified as impacts)and air pollution(classified as state)were the most important(such as“odor-burnt plastic”and“odor-acrid”).Complainants perceived odor annoyance as a primary environmental concern,possibly related to two main drivers:“odor-factory”and“odorsfarms”.The proposed approach has several theoretical and practical implications:text mining may quickly and efficiently address citizen needs,providing the basis toward automating(even partially)the complaint process;and the DPSIR framework might support the planning and organization of information and the identification of stakeholder concerns and priorities,as well as metrics and indicators for their assessment.Therefore,integration of the DPSIR framework with the text mining of environmental complaints might generate a comprehensive environmental knowledge base as a prerequisite for a wider exploitation of analysis to support decision-making processes and environmental management activities.
基金supported by National Natural Science Foundation of China(Grant 62422308).
文摘On the power supply side,renewable energy(RE)is an important substitute to traditional energy,the effective utilization of which has become one of the major challenges in risk-constrained power system operations.This paper proposes a risk-based power dispatching strategy considering the demand response(DR)and RE utilization in the stochastic optimal scheduling of parallel manufacturing process(PMP)in industrial manufacturing enterprises(IME).First,the specific production behavior model of PMP is formulated to characterize the flexibility of power demand.Then,a two-step strategic model is proposed to comprehensively quantify multiple factors in the optimal scheduling of DR in PMP loads considering risk-based power system dispatch,thermal generators,wind power integration.Case studies are based on the modified IEEE 24-bus power system,which verify the effectiveness of the proposed strategy in optimally coordinating IME assets with generation resources for promoting the RE utilization,as well as the impacts of power transmission risk on decision performance.
基金supported by the Joint Research Fund in Smart Grid under cooperative agreement between the National Natural Science Foundation of China(NSFC)and the State Grid Cooperation of China(SGCC,U1966601)the Fundamental Research Funds for the Central Universities of China(2023CDJYXTD-004).
文摘Renewable energy sources(RES)have strong uncertainties,which significantly increase the risks of power imbalance and load shedding in composite power systems.It is thus necessary to evaluate the operational reliability for guiding economic dispatch and reducing the risks.Current methods cannot meet the requirement for the operational timeliness of reliability evaluations due to the high computa-tional complexity of the optimal power flow(OPF)calculations of massive contingencies.This paper pro-poses a fully analytical approach to construct fast-to-run analytical functions of reliability indices and avoid reassessments when the load and RES change.The approach consists of uniform design(UD)-based contingency screening and a modified stochastic response surface method(mSRSM).The contin-gency screening method is used to select critical contingencies while considering the uncertainties.The mSRSM is used to construct the analytical functions of the load shedding to the load and RES gener-ation for the selected contingencies.An analytical function of a smooth virtual variable that maps to the load shedding is established in such a way that,when the load and RES vary,the reliability can be assessed within a very short time rather than using laborious OPF calculations.Case studies illustrate the excellent performance of the proposed method for real-time reliability evaluation.
文摘In this paper,the isogeometric analysis(IGA)method is employed to analyze the oscillation characteristics of functionally graded triply periodic minimal surface(FG-TPMS)curved-doubly shells integrated with magneto-electric surface layers(referred to as"FG-TPMS-MEE curved-doubly shells")subjected to low-velocity impact loads.This study presents low-velocity impact load model based on a single springmass(S-M)approach.The FG-TPMS-MEE curved-doubly shells are covered with two magneto-electric surface layers,while the core layer consists of three types:I-graph and Wrapped Package-graph(IWP),Gyroid(G),and Primitive(P),with various graded functions.These types are notable for their exceptional stiffness-to-weight ratios,enabling a wide range of potential applications.The Maxwell equations and electromagnetic boundary conditions are applied to compute the change in electric potentials and magnetic potentials.The equilibrium equations of the shell are derived from a refined higher-order shear deformation theory(HSDT),and the transient responses of the FG-TPMS-MEE curveddoubly shells are subsequently determined using Newmark's direct integration method.These results have applications in structural vibration control and the analysis of structures subjected to impact or explosive loads.Furthermore,this study provides a theoretical prediction of the low-velocity impact load and magneto-electric-elastic effects on the free vibration and transient response of FG-TPMS-MEE curved-doubly shells.
基金supported by the National Natural Science Foundation of China (Grant No. 41271003)the National Basic Research Program of China (Grants No. 2010CB428403 and 2010CB951103)
文摘Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity analysis of hydrological model is a key step in model uncertainty quantification, which can identify the dominant parameters, reduce the model calibration uncertainty, and enhance the model optimization efficiency. There are, however, some shortcomings in classical approaches, including the long duration of time and high computation cost required to quantitatively assess the sensitivity of a multiple-parameter hydrological model. For this reason, a two-step statistical evaluation framework using global techniques is presented. It is based on （1） a screening method （Morris） for qualitative ranking of parameters, and （2） a variance-based method integrated with a meta-model for quantitative sensitivity analysis, i.e., the Sobol method integrated with the response surface model （RSMSobol）. First, the Morris screening method was used to qualitatively identify the parameters＇ sensitivity, and then ten parameters were selected to quantify the sensitivity indices. Subsequently, the RSMSobol method was used to quantify the sensitivity, i.e., the first-order and total sensitivity indices based on the response surface model （RSM） were calculated. The RSMSobol method can not only quantify the sensitivity, but also reduce the computational cost, with good accuracy compared to the classical approaches. This approach will be effective and reliable in the global sensitivity analysis of a complex large-scale distributed hydrological model.
