Effects of connected automated vehicle on stability and energy consumption of heterogeneous traffic flow system

With the development of intelligent and interconnected traffic system,a convergence of traffic stream is anticipated in the foreseeable future,where both connected automated vehicle(CAV)and human driven vehicle(HDV)will coexist.In order to examine the effect of CAV on the overall stability and energy consumption of such a heterogeneous traffic system,we first take into account the interrelated perception of distance and speed by CAV to establish a macroscopic dynamic model through utilizing the full velocity difference(FVD)model.Subsequently,adopting the linear stability theory,we propose the linear stability condition for the model through using the small perturbation method,and the validity of the heterogeneous model is verified by comparing with the FVD model.Through nonlinear theoretical analysis,we further derive the KdV-Burgers equation,which captures the propagation characteristics of traffic density waves.Finally,by numerical simulation experiments through utilizing a macroscopic model of heterogeneous traffic flow,the effect of CAV permeability on the stability of density wave in heterogeneous traffic flow and the energy consumption of the traffic system is investigated.Subsequent analysis reveals emergent traffic phenomena.The experimental findings demonstrate that as CAV permeability increases,the ability to dampen the propagation of fluctuations in heterogeneous traffic flow gradually intensifies when giving system perturbation,leading to enhanced stability of the traffic system.Furthermore,higher initial traffic density renders the traffic system more susceptible to congestion,resulting in local clustering effect and stop-and-go traffic phenomenon.Remarkably,the total energy consumption of the heterogeneous traffic system exhibits a gradual decline with CAV permeability increasing.Further evidence has demonstrated the positive influence of CAV on heterogeneous traffic flow.This research contributes to providing theoretical guidance for future CAV applications,aiming to enhance urban road traffic efficiency and alleviate congestion.

Nonlinear Violence in Nonlinear Oscillations at High Energy

This paper focuses on the characteristics of solutions of nonlinear oscillatory systems in the limit of very high oscillation energy, E;specifically, systems, in which the nonlinear driving force grows with energy much faster for x(t) close to the turning point, a(E), than at any position, x(t), that is not too close to a(E). This behavior dominates important aspects of the solutions. It will be called “nonlinear violence”. In the vicinity of a turning point, the solution of a nonlinear oscillatory systems that is affected by nonlinear violence exhibits the characteristics of boundary-layer behavior (independently of whether the equation of motion of the system can or cannot be cast in the traditional form of a boundary-layer problem.): close to a(E), x(t) varies very rapidly over a short time interval (which vanishes for E → ∞). In traditional boundary layer systems this would be called the “inner” solution. Outside this interval, x(t) soon evolves into a moderate profile (e.g. linear in time, or constant)—the “outer” solution. In (1 + 1)-dimensional nonlinear energy-conserving oscillators, if the solution is reflection-invariant, nonlinear violence determines the characteristics of the whole solution. For large families of nonlinear oscillatory systems, as E → ∞, the solutions for x(t) tend to common, indistinguishable profiles, such as periodic saw-tooth profiles or step-functions. If such profiles are observed experimentally in high-energy oscillations, it may be difficult to decipher the dynamical equations that govern the motion. The solution of motion in a central field with a non-zero angular momentum exhibits extremely fast rotation around a turning point that is affected by nonlinear violence. This provides an example for the possibility of interesting phenomena in (1 + 2)-dimensional oscillatory systems.

Experimental study of power consumption, local characteristics distributions and homogenization energy in gas–liquid stirred tank reactors

In this paper, the power consumption, the vertical local void fraction and the local gas–liquid interfacial area are investigated in the aerated stirred tank reactors(STRs) equipped with a rigid-flexible impeller. Meanwhile, the regressive correlation based on power consumption and interfacial area is proposed. Then a novel homogenization energy(HE = RSDPtm) expression based on power consumption and local interfacial area is redefined and used to indicate the mixing efficiency. The optimal operating mode is selected based on the change of the HE value. This paper can provide research ideas for structural optimization of stirred reactors.

Design aspect of a novel L-shaped pulsed column for liquid–liquid extraction applications: Energy consumption and the characteristics velocity concept

This article deals with the evaluation of the consumption of energy for a steady state solvent extraction in a novel L-shaped pulsed sieve-plate column, which is highly required for design and optimization of the periodic flow processes for industrial applications. In this regard, a comprehensive evaluation on the energy consumption in case of a pulsed flow for three different chemical systems is conducted and besides the influence of pulsation intensity, the effect of geometrical parameters including the plate spacing and the plate free area is investigated as well. Moreover, the concept of characteristic velocity models at flooding points is evaluated with respect to the variation of pressure drop along the column at different operational conditions.

Energy Consumption and Energy Use Characteristics of High-Rise Hotels: A Case Study of Xi'an, Shaanxi

In this paper, 5 high-rise hotels in Xi'an were selected for research, their energy consumption data from 2015 to 2016 were collected and analyzed, their comprehensive energy consumption per unit area was compared by using the standard coal coefficient, and their energy use characteristics and influencing factors were obtained. The test analyzed various parameters of the indoor environment and evaluated the indoor environmental quality according to the specifications and standards. Starting from the perspective of energy use systems, this paper found energy consumption priorities and problems of these hotels, and proposed feasible energy conservation measures, in a view to providing a reference for energy conservation design of high-rise hotels in Xi'an.

Modified characteristic finite difference fractional step method for moving boundary value problem of nonlinear percolation system

A fractional step scheme with modified characteristic finite differences run- ning in a parallel arithmetic is presented to simulate a nonlinear percolation system of multilayer dynamics of fluids in a porous medium with moving boundary values. With the help of theoretical techniques including the change of regions, piecewise threefold quadratic interpolation, calculus of variations, multiplicative commutation rule of differ- ence operators, multiplicative commutation rule of difference operators, decomposition of high order difference operators, induction hypothesis, and prior estimates, an optimal order in 12 norm is displayed to complete the convergence analysis of the numerical algo- rithm. Some numerical results arising in the actual simulation of migration-accumulation of oil resources by this method are listed in the last section.

Deriving Energy-Gap of Some Nonlinear Hamiltonians by Invariant Eigen-operator Method

By virtue of the invariant eigen-operator method we search for the invariant eigen-operators for someHamiltonians describing nonlinear processes in particle physics.In this way the energy-gap of the Hamiltonians can benaturally obtained.The characteristic polynomial theory has been fully employed in our derivation.

A Data Analytics Study on Building Characteristics Impacting Energy Consumption in Single-Family Attached Homes

San Antonio, Texas is the seventh largest city in the United States with a population of 1.4 million people, and ranked among the fastest growing cities. To assess the implications of past and present building practices within the residential sector on future energy consumption, the energy utilization of single-family attached homes (SFAH) in Bexar County, Texas is studied. The available dataset includes 3932 SFAH records representing about 33% of the total number of SFAHs within the county. The study is based on pairing and analyzing data at the individual building level from a variety of sources including the buildings’ physical characteristics, access to fuels, and monthly energy consumption. The results indicate that the area of conditioned space, presence of swimming pools, number of stories, presence of fireplaces, fuel-type, and number of shared walls are a significant factor on the energy consumption of single-family attached homes. In terms of energy consumption, all-electric two-story homes sharing two walls are the most energy efficient among SFAHs. This study can aid comprehensive master planning efforts for developing sustainable communities by highlighting key features of SFAHs and making the case for higher density housing as a viable and more energy efficient alternative to single-family detached homes (SFDH).

基于转换点调控的怀山药多相态微波干燥及品质特性

为解决冻干和冻干-微波真空联合干燥技术存在的耗时长、能耗高、设备成本高等问题,同时获得品质较好的干制品,以怀山药为对象开展多相态微波干燥(multiphase microwave drying,MMD)研究,通过不同微波功率加载方案实现转换点调控,探究转换点干基含水率(0.36、0.59、0.79 g/g)对怀山药干制品品质的影响。并以真空冷冻干燥、微波冷冻干燥和微波真空干燥为对照,研究不同干燥方式对怀山药干燥特性、能耗和品质特性(复水性、收缩率、色泽、硬度、脆度、微观结构)的影响。结果表明:随着微波功率水平的增加,怀山药MMD转换点干基含水率增大,产品复水性降低,收缩程度增大,硬度变大,细胞结构破损程度增加。MMD方案Ⅰ(转换点干基含水率0.36 g/g)干燥时间与微波冷冻干燥相比缩短31.3%,能耗相比真空冷冻干燥、微波冷冻干燥分别降低68%、34%,同时,所得怀山药干制品具有良好的品质和均匀的微观孔隙结构,其复水比(2.44±0.04)、收缩率(0.88±0.02)、色泽、硬度(4.95±0.45)N、脆度(2.48±0.51)N与微波冷冻干燥无明显差异(P>0.05)。微波真空干燥虽所需能耗低,但其产品复水性最差,收缩最为严重。综合考虑高效低能耗干燥与产品品质提升的需求,可通过转换点调控的多相态微波干燥实现高品质怀山药加工。

基于行驶特征区间划分的重型载货汽车实际道路能耗评价方法

提出一种基于行驶特征区间划分的能耗评价方法。通过对中国货车行驶工况的工况点分布特征进行分析,确定了速度和加速度区间的数量与边界的划分方案。考虑道路坡度的影响,进行实际道路试验数据筛选,并用于计算不同行驶特征区间内的燃油消耗量平均值。结合中国货车行驶工况在不同行驶特征区间内的累计行驶里程,计算能耗评价结果。为了验证该方法的有效性,开展了3次底盘测功机试验和2次实际道路行驶试验,结果表明,所提出的能耗评价方法能提高重型载货汽车实际道路能耗评价结果的复现性。

基于控温控湿的沙棘红外联合热风干燥均匀性与工艺

新鲜沙棘含水率高且易腐烂变质,干燥是延长货架期的重要方式之一。针对现有沙棘热风干燥周期长、品质差、能耗高等问题,该研究基于控温控湿设计了一种红外联合热风干燥装置,并对装置的气流分配室结构进行了优化,设计了一种圆柱形扰流板和方形挡风板,利用数值模拟软件COMSOL对干燥装置中速度场、温度场和湿度场进行了模拟,结果表明通过增加半圆柱扰流板能够改变干燥层间气流量,解决干燥不均匀性问题;借助增设扰流板能够提高气流速度,利用自由流区域高温低湿干燥介质的干燥能力,防止干燥层内不同区域出现干燥不均匀的现象。优化后的干燥室结构将5个干燥层间的最大速度偏差比显著降低。以沙棘为研究对象对干燥工艺进行了试验研究。结果表明,不同干燥温度对沙棘控温控湿红外联合热风干燥时间有显著影响,干燥水分比随干燥时间的增加呈现指数下降趋势。基于层次分析法得到各干燥特性和干燥品质权重,采用综合评价方法得到不同干燥温度下75℃干燥条件综合评分最高。不同介质湿度干燥条件下,当介质湿度为10%干燥时,干燥所需能耗最低,干燥后沙棘复水比最高,具有最高的维生素C(vitamin C,Vc)保留率和总黄酮含量,综合评分最高。40%介质湿度不同持续时间下,40 min得到的沙棘亮度值、复水比、Vc保留率和总黄酮含量最高,综合评分最高。该研究明确了控温控湿沙棘红外联合热风干燥最优工艺,对提升沙棘产地初加工机械化水平,促进沙棘产业健康持续发展具有重要意义。

新疆能源消费碳排放时空特征及能源结构调整路径探讨

新疆作为我国重要的能源生产与供给基地,合理的协调经济发展与能源碳排放之间的关系,是实现其经济可持续发展与节能减排目标的重要前提。本文在整理新疆各类统计数据的基础上利用空间自相关对新疆2000—2020年能源消费碳排放的时空特征进行了测算和分析。结果表明:(1)研究期间新疆能源消费碳排放总量呈现逐年增加的趋势,但碳排放强度整体上呈现下降趋势;(2)碳排放强度的空间分布特征表现为:天山东坡碳排放强度较高,准噶尔北缘、天山北坡和昆仑山北坡则相对较低,并且具有明显的集聚特点;(3)在全球变暖与碳减排的大背景下,新疆需要从区域资源禀赋特点入手,建立差异化的能源结构调整策略,通过构建多能互补的绿色能源网络,促进区域实现“双碳”目标和社会经济的高质量发展。

基于差异特性水泵机组的优选与调控

为有效降低泵站因理论抽水装置效率偏离实际情况产生的方案误差,在聚类方法的基础上,利用历史监测数据对泵站内各抽水装置的特性曲线进行校正,同时将校正结果运用到泵站优化调度模型中,构建基于差异特性水泵机组的泵站优化调度模型,以实现站内机组的智能优选与调控.研究结果表明:校正后曲线的理论抽水装置效率比校正前精度平均提高18.8%,更符合工程实际;相比于人工经验调度方案,基于校正后曲线的差异特性水泵机组优化方案能耗平均降低了9.08%,成本平均降低了3.59%,优于人工经验调度方案;对校正后的多台水泵机组性能曲线进行对比发现,因安装位置、累计运行台时及磨损程度不同,导致泵站内同型号水泵的抽水装置效率产生差异,最大偏差达14.63%,说明长时间运行时的泵站已无法直接通过均分流量完成最优分配,进一步证明了水泵机组差异特性研究的必要性.

博弈视角下电-气互联综合能源系统多目标协同优化

考虑到现有综合能源系统多目标优化存在主观性,文中提出一种基于非合作博弈理论的单主体多目标协同优化方法。首先,建立耦合配电网络、配气网络和能源站的电-气互联综合能源系统模型。为使优化调度结果更贴近现实,在配气网模型中采用可变压缩比的压缩机模型,并考虑其非线性耗量特性。其次,基于非合作博弈理论,将能源站单一利益主体的经济性目标和环保性目标视为完全平等且理性的虚拟博弈者,其策略空间由系统内各设备约束组成。再次,为确保博弈模型存在纳什均衡解,在新增辅助变量和约束作用下将收益函数(目标函数)转为拟凸的可微函数。采用凸松弛方法处理模型中非凸非线性约束,并提出非线性迭代策略加速松弛收紧。为便于求解出纳什均衡,使用Nikaido-Isoda函数重构收益函数,将原模型转变为全局最优问题。最后,通过算例验证了所提方法的有效性。

TY含水页岩气藏产量递减规律及可采储量预测

含水页岩气藏具有产量递减快、能量消耗大的特点。文中结合页岩气藏生产过程理论研究,提出表征页岩气藏产能、产水和产出效率变化的3类指标,分析了含水页岩气藏在不同生产阶段的生产动态变化特点;在对比不同页岩气藏产量递减分析方法的基础上,建立了可描述含水页岩气藏生产全过程的产量递减预测模型;利用衰竭开发条件下的产量-能量置换守恒原则,提出了一个基于累计产气量与累计能耗关系的可采储量预测方法,并分析了其适用性。研究结果表明,该方法可以较全面、准确地预测含水页岩气藏的产量递减规律和可采储量,为此类气藏的合理开发提供技术支持。

基于企业聚类的某省化纤行业节能减碳潜力分析

化纤行业在“双碳”战略目标下面临着巨大的节能减碳压力,需要分析行业的能耗现状与节能减碳潜力。以中国化纤行业第一大省的146家化纤企业为研究对象,利用企业能耗数据分析行业的能耗特征,基于聚类算法对企业进行分类并计算行业的节能减碳潜力。结果表明,该省2013—2021年化纤行业的能耗结构和碳排放结构均以电力贡献为主,节能潜力占行业能耗量的24.63%,减碳潜力占行业碳排放量的22.91%。大型企业和能耗强度偏高的小型企业节能减碳建议以减少原煤消耗为主,中小型企业节能减碳建议以减少电力消耗为主。

考虑碳减排的火电机组煤耗基准值研究

燃煤机组作为新型电力系统的基础和压舱石,其高效经济运行是平稳达成“双碳”目标可行技术路径中的重要一环。基于机组历史运行数据建立稳态数据库和进行工况划分,采用灰色关联度分析方法,提取能效特征指标,并基于k-means聚类算法确定机组能效特征基准值,导入到计算模型获得机组供电煤耗最优基准值。最后,通过该方法获取一1 000 MW机组典型工况下的能效特征基准值,计算机组供电煤耗最优基准值,并以碳排放效益评估分析机组低碳运行的经济性,验证了该方法实际应用的可靠性。

能源供给侧与消费侧碳排放的责任核算与驱动因素——基于“收入者责任”视角的考察

在大力推动“碳达峰、碳中和”的背景下,碳排放核算体系的科学性对碳减排责任界定的合理性至关重要。本文采用Ghosh投入产出模型,基于“收入者责任”视角对中国能源供给侧与消费侧省份的碳排放分别进行了核算和特征事实分析,并对其驱动因素进行了考察。结果显示:从时序变化趋势来看,“收入者责任”视角下能源供给侧和消费侧省份的碳排放均呈现出增长趋势;从动态演变情况来看,能源消费侧省份的碳排放分布呈现出明显的延展收敛趋势,而能源供给侧省份出现了微弱的梯度效应和分化效应;从责任差异来看,能源供给侧省份需要承担更多的碳排放责任;从行业集中度来看,能源消费侧省份产业部门碳排放的集中程度明显较低;从网络结构来看,“收入者责任”视角下碳排放网络总体上呈现“核心—边缘”特征;从驱动因素来看,规模效应是导致能源供给侧与消费侧碳排放增长的首要因素,而技术效应是降低能源供给侧与消费侧碳排放的关键驱动力。

基于神经网络的电力芯片能耗优化方法

针对部分类型电力芯片能耗优化效果较差的问题,提出基于神经网络的电力芯片能耗优化方法。构建电力芯片能耗模型,提取芯片能耗特征,采用BP神经网络对其进行评价。实验结果表明,该方法可对多种类型的电力芯片能耗进行优化,包括开关能耗、泄漏能耗等,从而降低芯片的总能耗。