Dynamic Analysis of A Deepwater Drilling Riser with A New Hang-off System

The safety of risers in hang-off states is a vital challenge in offshore oil and gas engineering.A new hang-off system installed on top of risers is proposed for improving the security of risers.This approach leads to a challenging problem:coupling the dynamics of risers with a new hang-off system combined with multiple structures and complex constraints.To accurately analyze the dynamic responses of the coupled system,a coupled dynamic model is established based on the Euler-Bernoulli beam-column theory and penalty function method.A comprehensive analysis method is proposed for coupled dynamic analysis by combining the finite element method and the Newmarkβmethod.An analysis program is also developed in MATLAB for dynamic simulation.The simulation results show that the dynamic performances of the risers at the top part are significantly improved by the new hang-off system,especially the novel design,which includes the centralizer and articulation joint.The bending moment and lateral deformation of the risers at the top part decrease,while the hang-off joint experiences a great bending moment at the bottom of the lateral restraint area which requires particular attention in design and application.The platform navigation speed range under the safety limits of risers expands with the new hang-off system in use.

Dynamic Time and Location Information in Ciphertext-Policy Attribute-Based Encryption with Multi-Authorization

Due to the mobility of users in an organization,inclusion of dynamic attributes such as time and location becomes the major challenge in Ciphertext-Policy Attribute-Based Encryption(CP-ABE).By considering this challenge;we focus to present dynamic time and location information in CP-ABE with mul-ti-authorization.Atfirst,along with the set of attributes of the users,their corre-sponding location is also embedded.Geohash is used to encode the latitude and longitude of the user’s position.Then,decrypt time period and access time period of users are defined using the new time tree(NTT)structure.The NTT sets the encrypted duration of the encrypted data and the valid access time of the private key on the data user’s private key.Besides,single authorization of attribute authority(AA)is extended as multi authorization for enhancing the effectiveness of key generation.Simulation results depict that the proposed CP-ABE achieves better encryption time,decryption time,security level and memory usage.Namely,encryption time and decryption time of the proposed CP-ABE are reduced to 19%and 16%than that of existing CP-ABE scheme.

Applying the Principle of Dynamic Equivalence in the Translation of the Heading of News Report

Nida's famous notion of Dynamic Equivalence in translation process is characterized by three stages - analysis, transfer and restructuring, which are explained in detail. The application of these principles are illustrated by providing step-by-step explanation on the translation process of headings of two news reports, which are selected from Far Eastern Economic Review.

Dynamic behavior of new cutting subgrade structure of expensive soil under train loads coupling with service environment

Expansive soil is sensitive to dry and wet environment change. And the volume deformation and inflation pressure of expansive soil may induce to cause the deformation failure of roadbed or many other adverse effects. Aimed at a high-speed railway engineering practice in the newly built Yun-Gui high-speed railway expansive soil section in China, indoor vibration test on a full-scaled new cutting subgrade model is carried out. Based on the established track-subgrade-foundation of expansive soil system dynamic model test platform, dynamic behavior of new cutting subgrade structure under train loads coupling with extreme service environment(dry, raining, and groundwater level rising) is analyzed comparatively. The results show that the subgrade dynamic response is significantly influenced by service conditions and the dynamic response of subgrade gradually becomes stable with the increasing vibration times under various service environment conditions. The vertical dynamic soil stress is related with the depth in an approximate exponential function, and the curves of vertical dynamic soil stress present a "Z" shape distribution along transverse distance. The peak value of dynamic soil stress appears below the rail, and it increases more obviously near the roadbed surface. However, the peak value of dynamic soil stress is little affected outside 5.0 m of center line. The vibration velocity and acceleration are in a quadratic curve with an increase in depth, and the raining and groundwater level rising increase both the vibration velocity and the acceleration. The vertical deformations at different depths are differently affected by service environment in roadbed. The deformation of roadbed increases sharply when the water gets in the foundation of expansive soil, and more than 60% of the total deformation of roadbed occurs in expansive soil foundation. The laid waterproofing and drainage structure layer, which weakens the dynamic stress and improves the track regularity, presents a positive effect on the control deformation of roadbed surface. An improved empirical formula is then proposed to predict the dynamic stress of ballasted tracks subgrade of expansive soil.

Design and Analysis of a New AUV's Sliding Control System Based on Dynamic Boundary Layer

The new AUV driven by multi-vectored thrusters not only has unique kinematic characteristics during the actual cruise but also exists uncertain factors such as hydrodynamic coefficients perturbation and unknown interference of tail fluid, which bring difficult to the stability of the AUV＇s control system. In order to solve the nonlinear term and unmodeled dynamics existing in the new AUV＇s attitude control and the disturbances caused by the external marine environment, a second-order sliding mode controller with double-loop structure that considering the dynamic characteristics of the rudder actuators is designed, which improves the robustness of the system and avoids the control failure caused by the problem that the design theory of the sliding mode controller does not match with the actual application conditions. In order to avoid the loss of the sliding mode caused by the amplitude and rate constraints of the rudder actuator in the new AUV＇s attitude control, the dynamic boundary layer method is used to adjust the sliding boundary layer thickness so as to obtain the best anti-chattering effects. Then the impacts of system parameters, rudder actuator＇s constraints and boundary layer on the sliding mode controller are computed and analyzed to verify the effectiveness and robustness of the sliding mode controller based on dynamic boundary layer. The computational results show that the original divergent second-order sliding mode controller can still effectively implement the AUV＇s attitude control through dynamically adjusting the sliding boundary layer thickness. The dynamic boundary layer method ensures the stability of the system and does not exceed the amplitude constraint of the rudder actuator, which provides a theoretical guidance and technical support for the control system design of the new AUV in real complex sea conditions.

Impact of the synergy between technology management and technological capability on new product development:a system dynamics approach

This paper employs system dynamics to explore how the synergy between technology management and technological capability affects new product development.The results show that the synergy between technology management and technological capability has positive impact on new product development.Moreover, the leading synergy processes between technology management and technological capability in different new product development stages are different.This paper deepens the theoretical understanding of how to achieve new product development, and also provides useful guidance for firms to implement new product development.

New Developments on Existence and Uniqueness of Solutions to Some Models in Atmospheric Dynamics

This survey is concerned with the new developments on existence and uniqueness of solutions of some basic models in atmospheric dynamics, such as two-and three-dimensional quasi-geostrophic models and three-dimensional balanced model. The main aim of this paper is to introduce some results about the global and local (with respect to time) existence of solutions given by the authors in recent years, but others' important contributions and the literature on this subject are also quoted. We discuss briefly the relationships among the existence and uniqueness, physical instability and computational instability. In the appendixes, some key mathematical techniques in obtaining our results are presented, which are of vital importance to other problems in geophysical fluid dynamics as well.

A Three-Stage Stochastic Dynamic Pricing Game Model Affected by New Products into the Market

In real-life marketing, a common phenomenon is that the prices of current product will have been cut down even the new product has not gone into market yet. Thus, it is very important for merchant to set the strategy which can make the excepted revenue maximum. So, this paper constructs a three-stage stochastic dynamic pricing game model for analyzing the influence of the uncertainty of entry timing of the new products on pricing of products being sold. By analyzing of the pricing strategy, there are big differences in the predictions of new product going into market between merchant and customers;the merchant will adopt cutting price for promotion strategy to reduce negative influence of the new products on the demand of the products sold now. Otherwise, the merchant will adopt the strategy of maximizing current period’s profit.

Experimental investigation and development of new correlation for influences of temperature and concentration on dynamic viscosity of MWCNT-SiO2(20-80)/20W50 hybrid nano-lubricant

In current research, MWCNT-SiO_2/oil hybrid nano-lubricant viscosity is experimentally examined. By dispersing 0.05%, 0.1%, 0.2%, 0.4%, 0.8% and 1% volume of MWCNTs and SiO_2 nanoparticle into the engine oil SAE 20W50, the temperature and solid volume fraction consequences were studied. At 40 to 100 ℃ temperature, the viscosities were assessed. The results indicated Newtonian behavior for the hybrid nano-lubricant. Moreover, solid volume fraction augmentation and temperature enhanced the viscosity enhancement of hybrid nano-lubricant. At highest solid volume fraction and temperature, nano-lubricant viscosity was 171% greater compared to pure 20W50. Existed models lack the ability to predict the hybrid nano-lubricant viscosity. Thus, a new correlation regarding solid volume fraction and temperature was suggested with R-squared of 0.9943.

The Dynamic Centre of the New Global Economic Landscape

Competition used to be a steady,slow-moving phenomenon,dominated by the giant companies of the Western world.Two-thirds of the companies listed on the Fortune Global 500 in the 1960s were still there 15 years later.New competitors were easy to spot because they were well known,

Research on Ecological Assessment and Dynamic Optimization of Energy-saving and New Energy Vehicle Business Model Based on Full Life Cycle Theory

The rapid development of China’s automobile industry has brought ever-increasing impact on resources,energy and environment,the energy-saving and new energy vehicles come into being accordingly.This article firstly systematically introduces the technical route of energy-saving and new energy vehicles of China,focusing on the key bottleneck problems arising from the construction process of current assessment system of the technical route for energy-saving and new energy vehicles,establishes the energy-saving and new energy vehicle business model assessment index system afterward based on the comparative analysis on energy-saving and new energy vehicle business assessment model and the full life cycle theory,and finally makes prospects and forecasts on vital problems of system boundary,dynamic optimization,simulation system of full life cycle assessment of energy-saving and new energy vehicle.

A New Inertial Sensing System for Dynamic Measurement of Parallel Machines

One way to solve the problem of measurement precision caused by deformity for thermal expansion, friction and load etc is to use an inertial sensor to measure a change in the length of the rod on a parallel machine. However, the characteristic of dynamic measurement in the inertial sensing system and the effects of the machine＇s working environment, bias error, misalignment and wide band random noise in inertial measurement data results in the in-accuracy of system measurement. Therefore, on the basis of the measurement system a new inertial sensing system is proposed; the drifting of error is restrained with a method of inertial error correction and the system＇s position and the velocity state variables are predicted by the data fusion. After measuring the whole 300mm movement in an experiment, the analyses of the experimental result showed that the application of the new inertial sensing system can improve the positional accuracy about 61% and the movement precision more than 20%. Measurement results also showed that the application of the new inertial sensing system for dynamic measurement was a feasible method to improve the machine＇s dynamic positioning precision. And with the further improvement of the low-cost solid-stateacceleramenter technology, the application of the machine can take a higher position and make the speed dynamic accuracy possible.

Construction of Dynamic Evaluation Model for Economic Benefits under Development of Low-Carbon New Energy

Because the static evaluation is unable to reflect the dynamic features of economic benefits and the contribution of sustainable development of low-carbon new energy to economic benefits is huge,this article puts forward the dynamic evaluation model of economic benefits under the development of low-carbon new energy.Total energy,energy consumption structure,industrial structure,GDP,total population and energy supply structure were taken as independent variables,and the carbon intensity was taken as the dependent variable.Through t-test and decision coefficient,total energy,energy consumption structure,GDP and total population were determined as the main factors of influencing low-carbon economy.Based on these four main factors,the dynamic evaluation index system of economic benefits was constructed.Experimental results show that the proposed model can comprehensively reflect the economic benefit level and the contribution of low-carbon new energy.Therefore,this method has high evaluation accuracy,which can provide scientific reference for the economic benefit management of relevant management departments.

OPENING NEW HORIZONS FOR VEHICLE SYSTEM DYNAMICS

The non-linear wheel-rail motional model is the first research breakthrough I have made in the field of vehicle system dynamics. The main external interference to a vehicle system in rail-borne transportation comes from the dynamic interaction between the wheel and the rail. To determine the forces exerted on the rail-contacting patches of a railcar is known to be one of the most complicated problems in rail haulage, expecially in its unsaturated state, i.e. before overall sliding occurs. Since the 1960s, many scholars, including K.L. Johnson and J.J.Kalker, have considered it a problem in rolling contact mechanics. However, none of the presented

Equating incremental dynamic analysis with static nonlinear analysis at near-field excitation

In an incremental dynamic analysis(IDA) using a set of ground motion records,nonlinear time history analysis needs to be performed on structures.It is well recognized that IDA calls for high computational efforts and the results are highly sensitive to selected ground motions.As a result,alternative static methods are needed.This study aims to introduce a new double-stage(N1- N2) static method to estimate capacity curves of MR frames.The technique is regulated to resemble IDA results with specific emphasis on near-field ground motions.Using an ensemble of 56 near-field earthquake records,required ID As have been carried out for SAC-Los Angeles 3-,9- and 20-story buildings and an additional 15-story building.The results of the proposed static method are compared with those from IDA,displacement-based adaptive procedure(DAP),and multimodal procedure(MMP).The results indicate that in addition to enhanced accuracy,very little time is required in the case of N1-N2 method.Thus,for the 3-story structure,the time required is less than 1 minute.The proposed N1-N2 method shows the best accuracy in terms of lateral mechanisms for the 15-story frame while for the other cases,the first mode load pattern leads to the best accuracy.

Mechanism of micro-wetting of highly hydrophobic coal dust in underground mining and new wetting agent development

The internal mechanism of the high hydrophobicity of the coal samples from the Pingdingshan mining area was studied through industrial,element,and surface functional group analysis.Laboratory testing and molecular dynamics simulations were employed to study the impact of three types of surfactants on the surface adsorption properties and wettability of highly hydrophobic bituminous coal.The results show that the surface of highly hydrophobic bituminous coal is compact,rich in inorganic minerals,and poorly wettable and that coal molecules are dominated by hydrophobic functional groups of aromatic rings and aliphatic structures.The wetting performance of surfactants as the intermediate carrier to connect coal and water molecules is largely determined by the interaction force between surfactants and coal(Fs-c)and the interaction force between surfactants and water(Fs-w),which effectively improve the wettability of modified coal dust via modifying its surface electrical properties and surface energy.A new type of wetting agent with a dust removal rate of 89%has been developed through discovery of a compound wetting agent solution with optimal wetting and settling performance.This paper provides theoretical and technical support for removing highly hydrophobic bituminous coal dust in underground mining.

Evaluating Urban Landscape Dynamics over Srinagar City and Its Environs

Rapid, unplanned and uncontrolled urbanization causes disorganized growth. The patterns of urban development are changing natural landscapes and their dynamics. This has necessitated understanding of spatial patterns of urbanization and prompted research. Urbanization being a dynamic phenomenon has been facing ambiguities regarding methods to study its dynamism. It has made operational, a wide-variety of spatial metrics methods utilizing multiple dates of remotely sensed data. The present work carries out the quantitative and qualitative analysis of urban growth of Srinagar by using Urban Landscape Analysis Tool (ULAT). Urbanized Area (UA), Urban Footprint (UF) and New Development (ND) maps are generated to quantify the degree of urbanization based on spatial density of built-up area. Comparative analysis of these maps in relation to the built-up spread pattern indicates that mostly the environs of the Srinagar city which includes mostly agricultural, vacant and marshy areas prominently in northern, western and southern areas contribute to the development of the city.

政治经济学视域下数字新质生产力的形成逻辑与内涵研究

数字技术快速发展,各行业数字化转型不断深化,数字新质生产力正在成为推动经济增长和社会进步的关键力量。为了全面解析数字新质生产力的形成逻辑和丰富内涵,进而推动其发展,本文采用文献分析、理论分析与数理推导的方法,基于马克思主义政治经济学的生产力理论,探讨了社会生产力的历史演进及其发展趋势,深入解读了数字新质生产力的本质及内涵、外延,重点分析其形成逻辑和作用特征。研究结果表明,数字新质生产力的本质是由前沿数字技术创新驱动的,更具包容性、更体现新内涵的先进生产力。数字新质生产力的基本内涵包括劳动者、劳动资料、劳动对象及其优化组合的跃升,外延涉及全要素生产率的提升和产业结构的优化两个核心方面。数字技术革命性突破、生产要素创新性配置以及产业深度转型升级三者的联合作用推动了数字新质生产力的形成,其作用特征表现为高科技、高效能和高质量。文章进一步阐释了数字新质生产力的构成,即以数字技术、数据要素、数字产业化与产业数字化为核心的动力机制与劳动者、劳动资料、劳动对象等生产要素相互渗透,进而提出了数字新质生产力的计算公式,用于评估其影响力。研究表明,数字新质生产力的出现既是对传统马克思主义生产力理论的继承,也是其创新发展,是社会生产力发展进入新阶段的具象表现之一,对数字新质生产力的深入研究,为理解并推动数字经济时代的高质量发展提供了重要视角。

后冬奥时代我国冰雪产业高质量发展的动力变革与实现路径

运用文献资料法和逻辑分析法对后冬奥时代我国冰雪产业高质量发展的基础能力、发展机遇、动力变革进行了研究。研究发现:冰雪产业自身变革发展模式、拓展地理空间、服务乡村振兴、区域协同等自身优势为高质量发展奠定了基础;北京冬奥会为我国冰雪产业的高质量发展提供了发展机遇,加快构建了冰雪产业高质量发展的新格局,促进了产品体系完善和多链融合;产业变革的动力来自供需平衡、市场主体支撑、要素驱动转化、制度环境、科技创新。因此笔者提出要加强顶层设计,构建中国特色现代化的高质量冰雪产业发展体系;提高效率,规范职能,建设协同高效的一流营商环境;加强健康引领,丰富供给类型,建设服务人民的冰雪体育公共服务体系;夯实开放理念,增强科技助力,建设创新融合低碳发展的冰雪产业市场机制;建立支撑冰雪产业高质量发展的人才培养体系;以更高水平的对外开放,深度融入全球冰雪产业格局等路径促进后冬奥会时代我国冰雪产业的高质量发展。

计及低电压穿越影响的感应电动机动态分群

随着新能源的大规模广泛并网,其对感应电动机动态等值建模的影响值得关注。该文提出了新能源电力系统中感应电动机动态分群新方法。分析了感应电动机与电网的交互作用,提出在现有基于感应电动机动态相似性分群的基础上,同时考虑机端电压动态相似性的分群可提高感应电动机动态等值精度。针对高比例新能源电力系统,研究发现感应电动机附近有新能源机组,且部分新能源机组在故障期间进入低电压穿越(LVRT)时,这些感应电动机动态特性具有显著差异。为此提出新能源电力系统中考虑感应电动机端口电压跌落深度的动态分群方法。算例分析表明,该文提出的兼顾感应电动机端口电压动态相似性以及端口电压跌落深度的分群方法具有较高的等值精度,且适应性强。