2,184 research outputs found
Energy and sustainable urban transport development in China: Challenges and solutions
This paper presents an overview of urban road transport development and challenges in energy consumption in China. It relates sustainable urban road transport development with energy consumption and environmental management. It analyzes the main challenges related to urban road transport development: energy security, low efficiency in energy utilization, and unsustainable environmental management. It also discusses necessary technological and policy initiatives to deal with these challenges: e.g., promoting the development and dissemination of cleaner vehicle technologies, substitution of LPG, CNG, LNG and biofuels for gasoline and diesel, strengthening regulations on vehicle emissions, expediting public transport development, and the effective management of the soaring private car
Enabling sustainable urban road transport in China: A policy and institutional perspective
This paper is an effort to investigate the approach to sustainable urban road transport in Chinese mega cities with an emphasis on policy and institutional perspectives. The study links the major “unsustainabilities” of China’s urban road transport with those deficiencies in urban road transport planning and management and China’s auto industry policy, and gives some suggestions and recommendations for policy change and adjustment. The paper also provides some examples of successful experiences from foreign cities in urban road transport development from which Chinese cities can learn
The Role of Institutional Support in Energy Technology Diffusion in Rural China
In the past China's rural areas, home to 70% of its population, suffered energy shortages.China's indigenous energy resources are limited, with the exception of coal.The widespread use of coal requires large investments in production and transport -making it costly-, and degrades the environment.As a result the Chinese government has implemented an energy policy that aims at the use of renewable energy resources and increasing energy efficiency.For this the Chinese government has reorganised its institutional framework, which now aims at learning and improving profitability to diffuse technologies.Simultaneously the decision to use a technology has been shifted from officials to the consumers and profitability of a technology has become the main decision criterion.This paper analyses the effect of learning and profitability in technology diffusion and looks at the effectiveness of the institutional efforts.
The simulation of magnetorheological elastomers adaptive tuned dynamic vibration absorber for automobile engine vibration control
The aim of this article is to investigate the use of a Dynamic Vibration Absorber to control vibration of engine by using simulation. Traditional means of vibration control have involved the use of passive and more recently, active methods. This study is different in that it involves an adaptive component in the design of vibration absorber using magnetorheological elastomers (MREs) as the adaptive spring.
MREs are kind of novel smart material whose shear modulus can be controlled by applied magnetic field. In this paper, the vibration mode of a simple model of automobile engine is simulated by Finite Element Method (FEM) analysis. Based on the analysis, the MREs Adaptive Tuned Dynamic Vibration Absorber (ATDVA) is presented to reduce the vibration of the engine. Simulation result indicate that the control frequency of ATDVA can be changed by modifing the shear modulus of MREs and the vibraion reduction efficiency of ATDVA are also evaluated by FEM analysis
Evaluation on the Effects of Deicing Chemicals on Soil and Water Environment
AbstractDeicing chemicals are widely used to clear the pavement snow in the cold areas of China and many other countries in winter, because of their simple operation and excellent snow-melting effect, which leads to more convenience for traffic and low probability of traffic accident in the city, especially in metropolis. However, with the ever-growing application of deicing chemicals, their negative effects on environment such as soil and water system increased dramatically. Based on the related researches in China and abroad, this paper summarized the two categories of deicing chemicals and their working principles, and then provided the unique characteristics of deicing chemicals’ effects on soil and water environment in large cities, which may need considerable quantity of the chemicals to relieve traffic congestion. What's more, main aspects of impacts by deicing chemicals on regional soil and water environment and the fundamental factors related to the aspects above respectively were generalized, in order to propose a conceptual model to evaluate the harmful effects. Moreover, this paper put forward some suggestions for the further research in this field to fulfill the model, and provided a scientific basis for the pollution prevention of deicing chemicals on urban environment
Climate warming, euxinia and carbon isotope perturbations during the Carnian (Triassic) Crisis in South China
The Carnian Humid Episode (CHE), also known as the Carnian Pluvial Event, and associated biotic changes are major enigmas of the Mesozoic record in western Tethys. We show that the CHE also occurred in eastern Tethys (South China), suggestive of a much more widespread and probably global climate perturbation. Oxygen isotope records from conodont apatite indicate a double-pulse warming event. The CHE coincided with an initial warming of 4 °C. This was followed by a transient cooling period and then a prolonged ~7 °C warming in the later Carnian (Tuvalian 2). Carbon isotope perturbations associated with the CHE of western Tethys occurred contemporaneously in South China, and mark the start of a prolonged period of carbon cycle instability that persisted until the late Carnian. The dry-wet transition during the CHE coincides with the negative carbon isotope excursion and the temperature rise, pointing to an intensification of hydrologic cycle activities due to climatic warming. While carbonate platform shutdown in western Tethys is associated with an influx of siliciclastic sediment, the eastern Tethyan carbonate platforms are overlain by deep-water anoxic facies. The transition from oxygenated to euxinic facies was via a condensed, manganiferous carbonate (MnO content up to 15.1 wt%), that records an intense Mn shuttle operating in the basin. Significant siliciclastic influx in South China only occurred after the CHE climatic changes and was probably due to foreland basin development at the onset of the Indosinian Orogeny. The mid-Carnian biotic crisis thus coincided with several phenomena associated with major extinction events: a carbonate production crisis, climate warming, δ 13 C oscillations, marine anoxia, biotic turnover and flood basalt eruptions (of the Wrangellia Large Igneous Province)
Phylogeography of a widespread terrestrial vertebrate in a barely-studied Palearctic region: green toads (Bufo viridis subgroup) indicate glacial refugia in Eastern Central Asia.
The phylogeography of western Palearctic species is relatively well studied, but data on Eastern Central Asia are scarce. We present one of the first data sets from a widespread terrestrial vertebrate (Bufo pewzowi) inhabiting Eastern Central Asian mountains and deserts to gain knowledge on its phylogeography in this region. We applied combined phylogenetic and demographic analyses to understand the evolutionary history using mitochondrial DNA D-loop variation of toads from 37 locations. Genetic structure of Bufo pewzowi is strongly affected by landscape: we found three haplotype groups in eastern Kazakhstan, Dzungaria and Tarim Basin, divided by the Tian Shan and Dzungarian Alatau ranges. A vicariant hypothesis may explain divergence among groups. The divergence time of the three major clades was estimated about 0.9 million years ago (confidence interval 0.5-1.4), and is discussed with respect to Quaternary uplifting and glaciation in the Tian Shan. Demographic analyses provided evidence for both historical bottlenecks and population expansions and suggested Pleistocene signatures. Glacial refugia were inferred in the Tarim Basin (around the Turpan depression), in southern Dzungaria (Urumqui region), at the northern foot of the Tian Shan (Gongnaisi) and perhaps at the Altai range (Terekti). Regional Post-Last Glacial Maximum dispersal patterns are proposed. A taxonomic hypothesis is presented. This study provides a detailed history of how a widespread terrestrial vertebrate responded to geological change and Quaternary glacial events in Eastern Central Asia and may have significance for future phylogeographic research in this understudied region
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