Factor Decomposition and Regression Analysis of the Energy Related Carbon Emissions in Shandong, China: A Perspective of Industrial Structure

An in-depth study of the energy related carbon emissions has important practical significance for carbon emissions reduction and structural adjustment in Shandong Province and throughout China.Based on the perspective of industrial structure,the expanded KAYA equation to measure the energy related carbon emissions of the primary industries(Resources and Agriculture)and secondary industries(Manufacturing and Construction)and tertiary industries(Retail and Service)was utilized in Shandong Province from 2011 to 2017.The carbon emissions among industries in Shandong Province were empirically analyzed using the Logarithmic Mean Divisia Index decomposition approach.The results were follows:(1)Under the three industrial dimensions,the energy structure effect and the energy intensity effect have a restraining influence on the carbon emissions of the three industries.(2)The development level effect and the employment scale effect play a pulling role in carbon emissions.(3)From the perspective of the employment structure effect of the primary industry,there is a restraining effect on carbon emissions,while the employment structure effects of the secondary and tertiary industries play a pulling role in carbon emissions,and the employment structure effect of the tertiary industry has a greater pulling effect on carbon emissions than the secondary industry.

Test analysis of detection of damage to a complicated spatial model structure

A two-stage damage detection approach is proposed and experimentally demonstrated on a complicated spatial model structure with a limited number of measurements. In the experiment,five known damage patterns,including 3 brace damage cases and 2 joint damage cases,were simulated by removing braces and weakening beam鈥揷olumn connections in the structure. The limited acceleration response data generated by hammer impact were used for system identification,and modal parameters were extracted by using the eigensystem realization algorithm. In the first stage,the possible damaged locations are determined by using the damage index and the characteristics of the analytical model itself,and the extent of damage for those substructures identified at stage I is estimated in the second stage by using a second-order eigen-sensitivity approximation method. The main contribution of this paper is to test the two-stage method by using the real dynamic data of a complicated spatial model structure with limited sensors. The analysis results indicate that the two-stage approach is ableto detect the location of both damage cases,only the severity of brace damage cases can be assessed,and the reasonable analytical model is critical for successful damage detection.

Survival Analysis Using Cox Proportional Hazards Regression for Pile Bridge Piles Under Wet Service Conditions

This paper studies the deterioration of bridge substructures utilizing the Long-Term Bridge Performance(LTBP)Program InfoBridge^(TM)and develops a survival model using Cox proportional hazards regression.The survival anal­ysis is based on the National Bridge Inventory(NBI)dataset.The study calculates the survival rate of reinforced and prestressed concrete piles on bridges under marine conditions over a 29-year span(from 1992 to 2020).The state of Maryland is the primary focus of this study,with data from three neighboring regions,the District of Columbia,Vir­ginia,and Delaware to expand the sample size.The data obtained from the National Bridge Inventory are condensed and filtered to acquire the most relevant information for model development.The Cox proportional hazards regres­sion is applied to the condensed NBI data with six parameters:Age,ADT,ADTT,number of spans,span length,and structural length.Two survival models are generated for the bridge substructures:Reinforced and prestressed concrete piles in Maryland and reinforced and prestressed concrete piles in wet service conditions in the District of Columbia,Maryland,Delaware,and Virginia.Results from the Cox proportional hazards regression are used to construct Markov chains to demonstrate the sequence of the deterioration of bridge substructures.The Markov chains can be used as a tool to assist in the prediction and decision-making for repair,rehabilitation,and replacement of bridge piles.Based on the numerical model,the Pile Assessment Matrix Program(PAM)is developed to facilitate the assessment and main­tenance of current bridge structures.The program integrates the NBI database with the inspection and research reports from various states’department of transportation,to serve as a tool for condition state simulation based on mainte­nance or rehabilitation strategies.

Ecological Structure and Prediction Equations for Estimating Tree Age, and Dendometric Parameters of <i>Acacia senegal</i>in the Senegalese Semi-Arid Zone—Ferlo

The development of equations to predict tree height, crown diameter, crown depth from stem diameter of a tree species enables arborists, researchers, and urban forest managers to model costs and benefits, analyze alternative management scenarios, and determine the best management practices for sustainable forests. The objective of this study was to develop regression prediction models for tree age, tree height, crown diameter, crown ratio and crown depth for A. senegal growing in Ferlo, in the northern Senegal. Four plantations of different years old (ISRA, 10 years old plantations, Ndodj, 8 years old plantations, Boulal, 5 years old plantations and Déali, 4 years old plantations) were selected. The following dendometric variables: crown height, crown diameter, stem diameter at the breast height, stem basal diameter (at 0.30 m) and the height from the tree base to first branch were measured on a total of 489 trees. The results suggested that the ecological structure of the different year old A. Senegal plantation revealed a bell-shaped form with left dissymmetric distribution indicating a predominance of individuals with small diameter at breast height. Allometry study of A. Senegal showed highly significant positive correlations (p = 0.00) between stem diameter at breast height, stem basal diameter, tree height, crown diameter and crown depth. Positive correlations were also found between crown diameter, tree height and crown height. Prediction models derived from these relationships can be used to estimate the tree height, stem diameter at breast height and crown depth from crown diameter with greater precision. As for A. Senegal age estimation, the established model is not strong as it can explain only 49.1% of the age variation.

Physics-based and data-driven modeling for stability evaluation of buried structures in natural clays

This study presents a hybrid framework to predict stability solutions of buried structures under active trapdoor conditions in natural clays with anisotropy and heterogeneity by combining physics-based and data-driven modeling.Finite-element limit analysis(FELA)with a newly developed anisotropic undrained shear(AUS)failure criterion is used to identify the underlying active failure mechanisms as well as to develop a numerical(physics-based)database of stability numbers for both planar and circular trapdoors.Practical considerations are given for natural clays to three linearly increasing shear strengths in compression,extension,and direct simple shear in the AUS material model.The obtained numerical solutions are compared and validated with published solutions in the literature.A multivariate adaptive regression splines(MARS)algorithm is further utilized to learn the numerical solutions to act as fast FELA data-driven surrogates for stability evaluation.The current MARS-based modeling provides both relative importance index and accurate design equations that can be used with confidence by practitioners.

Suggestion of advanced regression model on friction angle of fault gouge in South Korea

Although friction characteristics of fault gouge are important to understand reactivation of fault,behavior of earthquake,and mechanism of slope failure,analysis results of fault gouge have low accuracy mostly than those of soils or rocks due to its high heterogeneity and low strength.Therefore,to improve the accuracy of analysis results,we conducted simple regression analysis and structural equation model analysis and selected major influential factors of friction characteristics among many factors,and then we deduced advanced regression model with the highest coefficient of determination(R^(2)) via multiple regression analysis.Whereas most coefficients of determination in simple regression analysis are below0.3-0.4,coefficient of determination in multiple regression analysis is remarkably large as 0.657.

基于回归分析法的矩形槽圆管吸能特性研究

为了研究矩形槽圆管吸能特性规律,提出了一种基于回归分析法的结构参数与吸能特性关系的拟合方法。针对轴向冲击下的圆管动态响应,首先,建立了6005A-T6材料的Cowper-Symonds本构模型,并验证了仿真模型的准确性;其次,设计了正交试验,建立了吸能特性与结构参数之间的计算模型;然后,利用多元线性与非线性回归分析方法对计算模型参数求解,并对比了两种拟合结果,得到了峰值力和吸能量的经验公式;接着,对比经验公式与有限元数值计算值表明,经验公式在研究范围内具有较高准确性,误差在8%以内;最后,引入吸能性能指标并使用遗传算法对圆管进行了结构优化,优化结果表明,在研究范围内当直径和槽端距最小、壁厚和槽宽最大、槽深最浅时,矩形槽圆管的吸能性能最优。

基于地下结构整体损伤表征的复合地震动参数构造及其性能验证

在地下结构抗震设计中,不同的输入地震动引起的地下结构响应有显著差异,因此,合理通过地震动参数选择输入地震动是正确开展地下结构抗震设计的重要前提。针对单一地震动参数难以表征地下结构地震动潜在破坏势问题,文章构造了能更好表征地下结构损伤破坏的复合地震动参数。具体开展了以下工作:提出基于变形与滞回耗能的地下结构整体损伤指标作为结构需求参数,以定量化评估地下结构的整体破坏状态。选取64条真实地震动记录作为输入地震动,开展四层三跨地铁车站地震弹塑性动力时程分析。基于分析结果提供的数据样本,采用偏最小二乘法从统计角度构造复合地震动参数。最后,选用100条真实地震动记录开展两层三跨地铁车站弹塑性动力时程分析,对文章所构造的复合地震动参数进行验证。对比分析复合地震动参数、12个常用地震动参数与地下结构整体损伤指数的回归统计特征。结果表明:复合地震动参数与结构需求数之间具有更好拟合优度值,其Pearson相关性、有效性也优于单一地震动参数。

淮河流域皖西大别山区地形因子与水系结构关联性分析

为深入研究淮河流域皖西大别山区地形因子与水系结构的量化关系,基于ArcGIS对研究区地形因子及水系结构特征参数进行计算与提取,采用多元线性回归方法分析了地形因子与水系结构特征参数之间的关系,得到了针对细度比、河道维系常数、分形维数、平均长度比和流域圆度的5个定量预测模型,并利用全局空间自相关及空间冷热点分析对水系格局及地形特征的空间分布进行了研究。结果表明:研究区地形因子与水系结构特征参数在空间上普遍存在相关关系,相关系数r最高达0.84;5个定量预测模型显著性水平P值均小于0.05,方差膨胀因子均小于10,模型拟合优度较高;研究区水系结构特征参数和地形因子存在“北冷南热”和“北热南冷”的显著空间分异特征。

地下工程咬合型管幕构件抗弯承载力研究

基于咬合型管幕试件的抗弯性能试验,研究了咬合型管幕试件的力学性能及破坏形态。为进一步研究关键结构参数对咬合型管幕试件抗弯性能的影响,运用ABAQUS建立了咬合型管幕试件的有限元模型,并通过室内试验验证了模型的正确性;进而分析了钢管咬合程度、钢管壁厚及钢筋直径对咬合型管幕试件抗弯性能的影响。结果表明:咬合型管幕试件抗弯性能良好,试件最终发生延性破坏;钢管咬合程度、钢管壁厚对试件的抗弯承载力影响显著,钢筋直径对试件的抗弯承载力影响不明显。最后,给出了钢管咬合程度、钢管壁厚及钢筋直径与抗弯承载力的关系式;并通过多元线性回归得到了咬合型管幕试件抗弯承载力简化计算公式。

双螺杆挤出机异形内筒结构强度影响因素分析

异形内筒的厚度δi、相交圆中心距e、相交圆直径d是影响双螺杆挤出机强度的3个主要结构参数(简称3因素),一次局部薄膜应力PL、一次局部薄膜应力+二次应力P_(L)+P_(b)+Q是压力容器应力强度评定的2个主要应力类别。对3因素设定4个水平,进行3因素4水平正交试验,利用极差分析方法与方差分析方法处理正交试验数据。研究结果表明,因素δi、e、d对双螺杆异形内筒上危险截面处的应力P_(L)、P_(L)+P_(b)+Q均具有显著影响,对PL影响的主次排序为δi、e、d,对P_(L)+P_(b)+Q影响的主次排序为δi、d、e,对PL、P_(L)+P_(b)+Q影响的最佳方案均为δi(4)d(1)e(1)。采用多元回归分析拟合出了异形内筒结构危险截面应力PL及P_(L)+P_(b)+Q的多元回归方程,可用于双螺杆挤出机异形内筒结构应力的估算。

The height-width ratio limited value for rubber bearing isolated structure computed by uniform design method

Rubber isolation is the most mature control technology in practical application, and is widely used by short rigid buildings. However, many high isolation buildings have been built around the world in recent years, which do not follow the existing criterions and codes. Many researchers began to research the special problems caused by larger height-width ratio isolation structures. The overturning effect of high height-width ratio structures with rubber bearing is firstly studied. Considering the main factors, such as the height-width ratio of structures, type of site, the designed basic acceleration of ground motion and the decouple factor in horizon, computing experiment is defined with the Uniform Design Method, which is also known as designing isolation structure. The forces of the bearing under edge of structures based on the position of the rubber bearing are calculated. The result indicates that the rubber bearings will lose its functionality under very high tension and compressing force of earthquake motion in horizon and vertical, when the height-width ratio is over a certain value. Thus, based on the calculation result of isolation structures defined in the uniform design method, regression analysis is conducted, and also the rubber edge force regression formula are gotten, which has higher correlation and smaller standard deviation. This formula can be used to roughly calculate whether the pull force occurs at the edge of the building. By the edge bearings of isolation structure minimum force formula, the height-width ratio limited value of the isolation structure is deducted when rubber bearing has minimum force of zero.

Finite element model updating for large span spatial steel structure considering uncertainties

In order to establish the baseline finite element model for structural health monitoring,a new method of model updating was proposed after analyzing the uncertainties of measured data and the error of finite element model.In the new method,the finite element model was replaced by the multi-output support vector regression machine(MSVR).The interval variables of the measured frequency were sampled by Latin hypercube sampling method.The samples of frequency were regarded as the inputs of the trained MSVR.The outputs of MSVR were the target values of design parameters.The steel structure of National Aquatic Center for Beijing Olympic Games was introduced as a case for finite element model updating.The results show that the proposed method can avoid solving the problem of complicated calculation.Both the estimated values and associated uncertainties of the structure parameters can be obtained by the method.The static and dynamic characteristics of the updated finite element model are in good agreement with the measured data.

Regression Formulations for the Stress at Hot Spot of Multiplanar Tubular DT Joints

Stress concentration analysis of multiplanar tubular DT joints plays an important role in the fatigue design of offshore platforms. A semi-analytic method for stress analysis under the condition of any loads is briefly introduced in the paper. Nineteen multiplanar tubular DT joints with one of two braces of the same dimension subjected to axial loads and out- of- plane bending moments are computed for parametric stress analysis by using the present method. The influence of geometrical parameters on the stresses of multiplanar tubular DT joints is discussed and compared with corresponding uniplanar T joints. The regression formulae for the stress at hot spot of multiplanar DT joints are found by modification of SCF of corresponding uniplanar T joints. The parametric formulae for the maximum stress by superposition. Finally, the influences of stiffening effect and load-interaction effect on the maximum stress of DT joints are discussed.

Age at first marriage and its relation to fertility in Bangladesh

The 2007 Bangladesh Demographic and Health Survey(BDHS)data are exploited to examine the effects of socioeconomic and demographic factors on age at first marriage linkage to reproductive behavior of Bangladeshi women.The mean age at first marriage of women is found to be 15.48 years.Multivariate logistic regression technique shows that place of residence,religion,region,wealth index,education,and occupation are significantly important factors for determining age at first marriage.The relationship between marriage and fertility suggests that women who marry at a younger age produce more children than women who marry late.Findings of this study show that if the age at first marriage of adolescents is increased by 1 year,the age at first birth is postponed by 0.728 years.With the increase in age at first marriage,the fecundability of women sharply rises,whereas the proportion of temporary sterility decreases.Although there is a positive association between age at first marriage and age-specific marital fertility rates,the total parity per woman at the end of the reproductive period is expected to reduce by 0.196 for each 1-year delayed marriage.

Determine the Factors of Female Early Age at First Cohabitation: A Case Study of Bangladesh

The main objective of the current study is to examine the existing situation of female early age at first cohabitation in Bangladesh as well as to identify the factors associated behind this issue. An analysis has been performed by using the secondary data of Bangladesh Demographic and Health Survey (BDHS), 2011. Chi-square test for dependency checking has been performed as bivariate analysis. After performing bivariate analysis, binary logistic regression analysis has been performed. To identify the significant variable, stepwise regression method has also been performed. The result of the study has revealed that women education, household economic status, area of residence, religion and geographical location have significant contribution for adolescent cohabitation. From this study it can be concluded that females who has low education and low socio-economic status are more likely to enter into cohabitation at early adulthood.

A Study on the Impact of China’s Demographic Structure on Human Capital Accumulation-Based on a Panel Data Model

With the development of the times,the role of human capital in economic growth has been highlighted.However,in the current academic world,the research on the topic of demographic structure and human capital accumulation is not closely integrated.China is now in a period of economic transformation and upgrading,and it is urgent to change the traditional economic growth model,increase human capital investment,and cultivate new growth momentum.Therefore,this paper examines the impact of China’s population structure on human capital accumulation by constructing a mathematical model based on relevant panel data of 31 provinces(municipalities and autonomous regions)from 2001 to 2020.The empirical results show that human capital accumulation in China has a certain lagging effect,while population age and urban-rural structure enhance human capital accumulation in both quantitative and qualitative terms,respectively.In addition,industrial transformation,economic growth level,and per capita income all have significant positive effects.The effect of education,on the other hand,is not significant,while the interaction between urbanization and industrial structure may hurt it.Based on this,this paper proposes targeted countermeasures and suggestions in terms of fully developing the population quality dividend,fully tapping the talent knowledge dividend,continuously improving the health dividend,and continually tapping the aging dividend.

淮南矿区地应力场分布特征及其演化过程

本文提出一种水压致裂和应力解除地应力测试之间数据转换和有效性验证的方法,统计得到了淮南矿区500~1050 m埋深范围内84组有效地应力测试数据,绘制地应力分布矢量图,结合淮南矿区地质构造特征和历次构造运动,回归分析了淮南矿区地应力场分布特征及其演化过程,得出如下结论:淮南矿区地应力场类型整体为构造应力场,应力场量级以高应力场为主,局部属于超高应力场;随着埋深的增加,最大水平主应力、最小水平主应力和垂直主应力量值逐渐增大,水平应力增加幅度小于垂直应力,应力场类型表现出由构造应力场向自重应力转变的趋势;淮南矿区多数测点最大水平主应力方向为NEE-WE向,局部为NW-SE向,区域构造主应力场方向大部分继承了喜马拉雅运动期的NEE-EW向,局部保留了燕山运动中期的NWW-SEE向;新生代松散层在煤系地层堆积,决定了垂直应力的大小。

地震下高度不等的相邻框架结构碰撞的易损性分析

针对相邻结构在地震下避免碰撞的安全水平亟待量化的问题,提出了相邻结构在地震下发生碰撞的易损性分析方法.该方法以峰值地面加速度作为地震动强度指标,以相邻结构最大相对位移作为工程需求参数,基于相邻结构的非线性有限元模型开展增量动力分析,分别利用最大似然估计和回归分析,包括单参数线性回归、双参数线性回归和双线性回归,来确定易损性函数的参数.以层高相等的6层和5层相邻钢筋混凝土框架结构为例,对比分析了不同间距下采用不同方法所得地震下发生碰撞的易损性曲线;计算了6层和4层、6层和3层相邻结构的碰撞易损性,分析了不同楼层数与楼层高度对碰撞易损性结果的影响.研究结果表明:当峰值地面加速度较大时,通过双线性回归所得易损性曲线与蒙特卡罗法结果最为接近,且结构间距越大,二者越接近;其他两种回归方法所得易损性偏大,最大似然估计所得易损性最保守;层高不等的6层和5层相邻结构的碰撞易损性最大,层高相等的6层和4层相邻结构次之,表明当相邻结构的周期比和碰撞位置的影响达到平衡时,碰撞易损性最大.

轮胎磨损性能与接地特性关系

轮胎磨损不仅影响车辆加速、安全及操控等诸多性能,而且产生的磨损颗粒物,还对环境造成污染。轮胎接地特性是影响轮胎磨损的关键因素。为探明轮胎磨损与接地特性之间关系,以205/55R16轮胎为研究对象,设计不同的胎面结构参数,选取摩擦能量损失率作为磨损性能评价指标,通过有限元方法获取接地特性参数。采用线性回归分析方法建立摩擦能量损失率与接地特性参数之间的回归方程,并研究不同胎面结构参数对接地特性及磨损性能的影响规律。分析结果表明,所建立的回归方程具有较高拟合精度,可以通过接地特性参数预测轮胎磨损性能,为轮胎磨损性能提升、胎面结构优化提供借鉴。