Petroleum substitution, greenhouse gas emissions reduction and environmental benefits from the development of natural gas vehicles in China

This study develops a bottom-up model to quantitatively assess the comprehensive effects of replacing traditional petroleum-powered vehicles with natural gas vehicles（NGVs） in China based on an investigation of the direct energy consumption and critical air pollutant（CAP） emission intensity, life-cycle energy use and greenhouse gas（GHG） emission intensity of NGV fleets. The results indicate that, on average, there are no net energy savings from replacing a traditional fuel vehicle with an NGV. Interestingly, an NGV results in significant reductions in direct CAP and life-cycle GHG emissions compared to those of a traditional fuel vehicle, ranging from 61% to 76% and 12% to 29%, respectively. Due to the increasing use of natural gas as a vehicle fuel in China（i.e. approximately 28.2 billion cubic metres of natural gas in2015）, the total petroleum substituted with natural gas was approximately 23.8 million tonnes（Mt）, which generated a GHG emission reduction of 16.9 Mt of CO2 equivalent and a CAP emission reduction of 1.8 Mt in 2015. Given the significant contribution of NGVs, growing the NGV population in 2020 will further increase the petroleum substitution benefits and CAP and GHG emission reduction benefits by approximately 42.5 Mt of petroleum-based fuel, 3.1 Mt of CAPs and 28.0 Mt of GHGs. By 2030, these benefits will reach 81.5 Mt of traditional petroleum fuel, 5.6 Mt of CAPs and 50.5 Mt of GHGs, respectively.

The use of permanent magnet motor for Tesla electric vehicle stimulates the demand for rare earth Nd

On March 13th,Reuters reported that the long run version of Tesla Model 3 will use permanent magnet motors.One of the materials for this type of motor is rare earth metal neodymium,which will further increase the supply pressure of neodymium.Governments around the world are committed to reducing the harmful emissions produced by fossil fuel cars,pushing up demand for electric vehicles

Using irrigation intervals to optimize water-use efficiency and maize yield in Xinjiang,northwest China

Worldwide, scarce water resources and substantial food demands require efficient water use and high yield.This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yield and water use efficiency(WUE) of high-yield maize under conditions of mulching and drip irrigation.A field experiment was conducted using three irrigation intervals in 2016: 6, 9, and 12 days(labeled D6, D9, and D12) and five irrigation intervals in 2017: 3, 6, 9, 12, and 15 days(D3, D6, D9, D12, and D15).In Xinjiang, an optimal irrigation quota is 540 mm for high-yield maize.The D3, D6, D9, D12, and D15 irrigation intervals gave grain yields of 19.7, 19.1–21.0, 18.8–20.0, 18.2–19.2, and 17.2 Mg ha^-1 and a WUE of 2.48, 2.53–2.80, 2.47–2.63, 2.34–2.45, and 2.08 kg m-3, respectively.Treatment D6 led to the highest soil water storage, but evapotranspiration and soil-water evaporation were lower than other treatments.These results show that irrigation interval D6 can help maintain a favorable soil-moisture environment in the upper-60-cm soil layer, reduce soilwater evaporation and evapotranspiration, and produce the highest yield and WUE.In this arid region and in other regions with similar soil and climate conditions, a similar irrigation interval would thus be beneficial for adjusting soil moisture to increase maize yield and WUE under conditions of mulching and drip irrigation.

Safety evaluation for railway vehicles using an improved indirect measurement method of wheel–rail forces

The wheel-rail force measurement is of great importance to the condition monitoring and safety evaluation of railway vehicles. In this paper, an improved indirect method for wheel-rail force measurement is proposed to evaluate the running safety of railway vehicles. In this method, the equilibrium equations of a suspended wheelset are derived and the wheel-rail forces are then be obtained from measured suspension and inertia forces. This indirect method avoids structural modifications to the wheelset and is applicable to the long-term operation of railway vehicles. As the wheel-rail lateral forces at two sides of the wheelset are difficult to separate, a new derailment criterion by combined use of wheelset derailment coefficient and wheel unloading ratio is proposed. To illustrate its effectiveness, the indirect method is applied to safety evaluation of rail- way vehicles in different scenarios, such as the cross wind safety of a high-speed train and the safety of a metro vehicle with hunting motions. Then, the feasibility of using this method to identify wheel-rail forces for low-floor light rail vehicles with resilient wheels is discussed. The values identified by this method is compared with that by Simpack simulation for the same low-floor vehicle, which shows a good coincidence between them in the time domain of the wheelset lateral force and the wheel-rail vertical force. In addition, use of the method to determine the high-frequency wheel-rail interaction forces reveals that it is possible to identify the high-frequency wheel-rail forces through the accelerations on the axle box.

High Spatial Resolution Mapping of Dykes Using Unmanned Aerial Vehicle(UAV) Photogrammetry: New Insights On Emplacement Processes

Remote sensing has played a pivotal role in our understanding of the geometry of dykes and dyke swarms on Earth,Venus and Mars(West and Ernst,1991;Mege and Masson,1995;Ernst et al.,2005).Since the 1970’s

Automated Autonomous Vehicles: Prospects and Impacts on Society

All automobile manufacturing companies, Google and Microsoft have announced recently their production of the Fully Automated Autonomous Vehicles (FAAVs), otherwise known as driverless cars. A few FAAVs would be available in the market as early as in 2018, but mostly in 2020’s. When FAAVs will be available to and become affordable by the average consumers, the implications to the society would be far reaching. The purpose of the paper is to examine the prospect of the popularity of FAAVs and their socio-economic implications to the future society of the World. The paper examines potential impacts on selected sectors of the society including changes in demand for automobiles, its impact on the use of oil, on the environment, and on urban land uses, to list a few.

Comparison of the Mutagenicity of Exhaust Emissions From Motor Vehicles Using Leaded and Unleaded Gasoline as Fuel

While Unleaded gasoline has the advantage of eliminating lead from automobile exhaust, its potential to reduce the exhaust gas and particles, merits further examination. In the present studies,the concentrations of hydrocarbons (HC) and earbon monoxides (CO) in emissions were analyzed on Santana engine Dynamometer under a standard test cycle, and total exhaust particles were collected from engines using leaded and unleaded gasoline. It was found that unleaded gasoline reduced the emissions of CO and HC, and decreased the quantity of vehicle exhaust particulate matters by 60%.With the unlead gasoline, only 23 kinds of organic substances, adsorbed in the particles, were identified by gas chromatography/mass spectrometer (GC/MS) while 32 components were detected using the leaded gasoline. The results of in vitro Salmonella/ microsomal test and micronucleus induction assay in CHL cells indicated that both types of gasoline increased the number of histidine-independent colonies and the frequencies of micronucleus induction; no significant differellce was found in their mutagenicity.

TaNRT2.1-6B is a dual-affinity nitrate transporter contributing to nitrogen uptake in bread wheat under both nitrogen deficiency and sufficiency

Multiple nitrate transporter(NRT)genes exist in the genome of bread wheat,and it is of great importance to identify the elite NRT genes for N-efficient wheat cultivar breeding.A candidate gene association study(CGAS)of six N use efficiency(NUE)related traits(grain N concentration(GNC),straw N concentration(SNC),grain yield(GY),grain N accumulation(GNA),shoot total N accumulation(STN)and N harvest index(NHI))was performed based on SNPs in 46 NRT2 genes using a panel composed of 286 wheat cultivars.CGAS identified TaNRT2.1-6B as an elite NRT gene that is significantly associated with four(NHI,SNC,GNA and GY)of the six NUE-related traits simultaneously.TaNRT2.1-6B is located on the plasma membrane and acts as a dual-affinity NRT.The overexpression of TaNRT2.1-6B increased the N influx and root growth of wheat,whereas gene silence lines resulted in the opposite effects.The overexpression of TaNRT2.1-6B also improved GY and N accumulation of wheat under either limited or sufficient N conditions.The data provide the TaNRT2.1-6B gene and the two associated SNP markers as promising powerful tools for breeding wheat cultivars with high N uptake ability and NUE.

Video-based measurement and data analysis of traffic flow on urban expressways

A new video-based measurement is proposed to collect and investigate traffic flow parameters. The output of the measurement is velocity-headway distance data pairs. Because density can be directly acquired by the reciprocal of headway distance, the data pairs have the advantage of better simultaneity than those from common detectors. By now, over 33 000 pairs of data have been collected from two road sections in the cities of Shanghai and Zhengzhou. Through analyzing the video files recording traffic movements on urban expressways, the following issues are studied：laws of vehicle velocity changing with headway distance, proportions of di0erent driving behaviors in the traffic system, and characteristics of traffic flow in snowy days. The results show that the real road traffic is very complex, and factors such as location and climate need to be taken into consideration in the formation of traffic flow models.

Cassini-Huygens results on Titan's surface

Our understanding of Titan, Saturn＇s largest satellite, has recently been considerably enhanced, thanks to the Cassini-Huygens mission. Since the Saturn Orbit Injection in July 2004, the probe has been harvesting new insights of the Kronian system. In particular, this mission orchestrated a climax on January 14, 2005 with the descent of the Huygens probe into Titan＇s thick atmosphere. The orbiter and the lander have provided us with picturesque views of extraterrestrial landscapes, new in composition but reassuringly Earth-like in shape. Thus, Saturn＇s largest satellite displays chains of mountains, fields of dark and damp dunes, lakes and possibly geologic activity. As on Earth, landscapes on Titan are eroded and modeled by some alien hydrology： dendritic systems, hydrocarbon lakes, and methane clouds imply periods of heavy rainfalls, even though rain was never observed directly. Titan＇s surface also proved to be geologically active - today or in the recent past - given the small number of impact craters listed to date, as well as a few possible cryovolcanic features. We attempt hereafter a synthesis of the most significant results of the Cassini-Huygens endeavor, with emphasis on the surface.

Long-term effects of main-body's obliquity on satellite formation perturbed by third-body gravity in elliptical and inclined orbit

A new non-simplified model of formation flying is derived in the presence of an oblate main- body and third-body perturbation. In the proposed model, considering the perturbation of the third- body in an inclined orbit, the effect of obliquity （axial tilt） of the main-body is becoming important and has been propounded in the absolute motion of a reference satellite and the relative motion of a follower satellite. From a new point of view, J2 perturbed relative motion equations and considering a disturbing body in an elliptic inclined three dimensional orbit, are derived using Lagrangian mechanics based on accurate introduced perturbed reference satellite motion. To validate the accuracy of the model presented in this study, an auxiliary model was constructed as the Main-body Center based Relative Motion （MCRM） model. Finally, the importance of the main-body＇s obliquity is demonstrated by several examples related to the Earth-Moon system in relative motion and lunar satellite formation keeping. The main-body＇s obliquity has a remarkable effect on formation keeping in the examined in-track and projected circular orbit （PCO） formations.

EXACT SOLUTION FOR RECTANGULAR SLAB WITH THREE EDGES SIMPLY-SUPPORTED AND OTHER FREE

In this paper,we give all-sided pastic analysis of the rectangular slab with three edges simply-supported and other free.Here we discuss the following four cases:(1)The uniformly distributedload over the area a slab.(2).A concentrated load act at midpoint of free edges slab.(3)A concen-trated load act at the center a slab.(4)The line load act along free edge of slab.

Design and test of a six-rotor unmanned aerial vehicle(UAV)electrostatic spraying system for crop protection

In recent years,multi-rotor unmanned aerial vehicle(UAV)crop protection operations have experienced tremendous growth.Compared with manual operations,they have advantages such as high operational efficiency,small pesticide dosage,and low pesticide hazards for humans.However,the tiny droplets produced during UAV spraying for crop protection are affected by the rotor air flow and will drift in all directions in an uncontrollable manner,severely affecting the pesticide deposition pattern and resulting in pesticide waste.To improve pesticide use efficiency during multi-rotor UAV spraying,an electrostatic spray system was designed based on electrostatic spray technology and a six-rotor UAV.The proper operation parameters for the UAV electrostatic spray were determined by test,which were spray altitude of 50 cm above the crop,spray pressure of 0.3 MPa and charging voltage of 9 kV.Field test was performed based on these parameters.The results showed that compared with non-electrostatic spray,the electrostatic spray improved by 13.6%in the average deposition density above the sampling device and 32.6%in the middle.The research can provide a reference for designing multi-rotor UAV electrostatic spray devices.

nvestigating the role of exiting vehicles and turn indicator usage in gap acceptance at single-lane roundabouts

Roundabouts are becoming a preferred form of intersection control type due to their safety and capacity benefits. Yield control at roundabout entries inherently reduces fuel consumption and emissions when compared to other conventional intersection types. However, these benefits can be limited by poor driver behavior and judgment when entering the roundabout. This research addresses the nature of gap distributions and use of turn indicators by exiting vehicles at three single-lane roundabouts in Vermont, New York, and Alaska. Presented here is a comparison of vehicle headways measured at two different locations in each roundabout. Rejected headways are analyzed in the context of priority abstaining events when entering drivers yield to vehicles exiting on the same leg of the roundabout suggesting that ＂true＂ critical gaps are being overestimated. Results indicate that exiting vehicles, particularly those that do not use their turn indicators when departing from the major-stream of traffic have an influence on the entry decision of drivers on the same approach. This behavior is of particular concern for intersection efficiency （i.e., delay） and sustainability （i.e., excess fuel consumption and emissions）. Results prompt the consideration of more consistent guidance on and enforcement of turn indicator use during roundabout negotiations.

基于MS5534B的无人机高度传感器

高度传感器是无人机的重要组成部分,具有数字输出的MS5534B很适合用于无人机高度传感器。详细介绍了传感器及接口电路和数据处理的方法,利用查表转换法实现了无人机高度传感器的功能。通过滤波算法有效地降低了采样噪声,运用Matlab对大量的压力-高度数据进行拟合,达到了设计要求,且成功应用于某小型无人机的飞行试验。

浅析车与车通信网络时间同步

本文首先描述了车联网中车与车通信网络的概念及架构,在分析了TD-SCDMA网络时间同步技术的基础上,重点讨论了基于TD-SCDMA的车载Ad Hoc网络时间同步技术及相应的同步算法,包括基于GPS/北斗的时间同步和基于分布的时间同步方案。