Category: Trransporation


What is Express


Express delivery, also known as express delivery or express delivery, refers to a new mode of transportation in which logistics enterprises (including freight forwarders) deliver documents or parcels entrusted by users quickly and safely from the sender’s door to the recipient’s door (hand delivery) through their own independent network or through joint venture cooperation (i.e. networking).
Express delivery can be divided into broad sense and narrow sense. In the broad sense, express delivery refers to the delivery of any goods (including bulk cargo); in the narrow sense, express delivery refers to the urgent delivery service of business documents and small pieces. The object of this textbook research and analysis is mainly the express industry in a narrow sense. According to the standard of service, express delivery generally refers to express delivery service completed within 48 hours. From the definition of express delivery, the following three characteristics of express delivery can be summarized:
From the economic category, express delivery is a branch of the logistics industry, and the research of express delivery belongs to the category of logistics.
From the perspective of business operation, express delivery is a new mode of transportation and an important link in the supply chain.
From the nature of operation, express delivery is a new service trade with high added value.

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Road Traffic Safety


It refers to the state in which personal casualties or property losses can be controlled at an acceptable level in the course of traffic activities. Traffic safety means that the possibility of loss to people or things is acceptable; if this possibility exceeds the acceptable level, it is unsafe. As a dynamic open system, the safety of road traffic system is not only restricted by internal factors of the system, but also disturbed by external environment of the system. It is closely related to human, vehicle and road environment. Any unreliable, unbalanced and unstable factors in the system may lead to conflicts and contradictions, resulting in unsafe factors or unsafe states.

Characteristic

(1) Traffic safety is a state under certain dangerous conditions, and it is not absolutely free from traffic accidents.
(2) Traffic safety is not an instantaneous result, but a description of the process or state of the traffic system in a certain period or stage.
(3) Traffic safety is relative and absolute traffic safety does not exist.
(4) For different periods and regions, the acceptable level of loss is different, so the criteria for measuring the safety of the transportation system are different.

Measures

Raising the level of road traffic safety is a matter of great benefit to the country and the people. Many experts and scholars have carried out extensive and in-depth research in this area. Traffic accident prevention is one of the main tasks of traffic safety and an important part of traffic engineering research. From the point of view of traffic engineering, it is considered that the prevention of traffic accidents should start from three aspects: laws and regulations, education and engineering, and from the point of view of people, vehicles, roads and environment, which constitute the four elements of road traffic, it is also considered that the prevention of traffic accidents should start from these four elements.

Improving Transportation Legal System

Strengthening the construction of road traffic safety laws and regulations system is a direct and effective measure to improve the overall level of road traffic safety. At present, the content of our country’s road traffic safety regulation system has been covered in a number of different laws, regulations and other traffic management normative documents, and it plays an active and important role in our country’s road traffic operation practice. With the development of the times, the legal system should be amended and adjusted accordingly.

Strengthen Traffic Safety Education

(1) Carry out traffic safety propaganda
Traffic safety propaganda is an important way to publicize and educate the masses. In carrying out propaganda activities, we should attach importance to achieving practical results and link traffic safety with everyone’s vital interests so as to arouse people’s attention to traffic safety. We should adopt propaganda forms popular with the masses, incorporate them in people’s daily work and life, and in cultural entertainment. At the same time, propaganda activities must mobilize the strength of society to the greatest extent possible, and strive for the depth and breadth of propaganda to ensure the quality of propaganda.
(2) Strengthen traffic safety education
Traffic safety education, like other cultural knowledge, should be carried out systematically from the early childhood. Before high school, every stage of education was listed as a compulsory course, which enabled students to establish the concept of traffic legal system, traffic safety, traffic ethics and safety prevailing concepts from the beginning of education. To educate the society, we should adopt different ways and methods according to different objects, and carry out targeted education.

Improve vehicle safety performance and maintain good vehicle condition

To improve the safety performance of vehicles, we should take active safety measures and passive safety measures.
(1) Active safety measures
1) Improve side and front vision, install reversing lights and alarms to prevent traffic accidents caused by blind areas.
2) Improve the perspective performance of windowpanes to prevent traffic accidents caused by rain, snow and frost.
3) Take anti-glare measures to improve the illumination of headlamp in order to prevent traffic accidents caused by glare and insufficient illumination of headlamp.
4) In terms of power performance, the overtaking acceleration capability should be improved and the drive anti-skid system (TCS) should be installed.
5) In the aspect of stability, we should improve the stability and portability of operation, such as installing electronic stabilization program (ESP).
6) In braking aspect, the auxiliary braking system, ABS anti-lock braking system, retarder and braking system fault alarm system are installed to improve the anti-skid performance of tires, so as to ensure safety.
7) In terms of accident prevention measures, we should also improve the recognition performance of vehicles, including rear, signs and driving directions, in order to prevent accidents.
8) Active anti-collision warning system is adopted. When the vehicle encounters danger, the driver can be reminded in time. If the driver fails to take measures in time because of his errors, the system can automatically take measures to avoid danger (such as deceleration, bypass, etc.).
(2) Passive safety measures
1) In-car measures
In-car measures mainly include increasing occupant space as much as possible, i.e. the strength of the car body, in order to reduce the deformation of the collision, using toughened glass or partition glass to reduce the injury of the occupant caused by the accident, enlarging the area of the steering wheel to make it elastic, and making the switches, knobs and handles inside the car as round as possible. Sliding and soft; door and roof have enough strength to protect the safety of passengers and facilitate rescue. In addition, fire prevention performance, safety belt and airbag play an important role in occupant safety protection.
2) Outside measures
Extravehicular measures mainly refer to minimizing injuries when crashing bicycles and pedestrians, such as bumpers should be as smooth and flexible as possible, movable rearview mirrors and fenders, and protective nets connected with trailers, etc., which will have certain effects on the protection of the weak traffic.

Strengthen the Construction of Road and Traffic Safety Facilities

(1) Improving road conditions
Considering from the aspect of road alignment design, we should strictly follow the horizontal and vertical curves of the designed road to make the curves and ramps conform to the technical standards of highway engineering. The safety of various alignment combinations should be fully considered.
(2) Improving road safety facilities
Road safety facilities mainly include partition belts, safety fences, traffic signs, markings, sight guidance facilities and anti-glare facilities. For urban traffic, pedestrian overpasses, underground passages, traffic safety islands, etc.
(3) Implementing traffic control
Traffic control can be divided into traffic signal control and traffic regulation control. Traffic signal control refers to the establishment of traffic lights at road entrances and intersections to reasonably control the driving of vehicles. Traffic regulation control includes setting up one-way traffic section, turning lane, bus lane, etc.
(4) Establishment of Traffic Information System
Traffic information is also known as traffic information. In order to ensure the safety and rapidity of vehicles traveling on automobile lanes or urban trunk roads, public security and management departments should report traffic congestion, weather, road ahead or temporary traffic control to drivers in time so that drivers can change their countermeasures in time.
(5) Establishing Emergency Rescue System for Accidents
The monitoring and forecasting system estimates possible accident areas according to abnormal weather conditions, adopts information collection and liaison system, and assigns special personnel to monitor and make preparations. When an accident occurs, advanced communication equipment and means should be used to quickly and reliably contact the relevant departments to deal with the accident in a timely and effective manner so as to ensure road safety and smoothness.
(6) Improving the Road Traffic Environment
The improvement of road traffic environment mainly includes two aspects: on the one hand, improving road environment, making drivers have good driving sight distance and constantly changing visual effect, improving the monotonous environment which makes drivers tired and irritable; on the other hand, improving traffic flow environment, keeping good density as far as possible, and avoiding as possible. No mixed traffic flow.

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Greenhouse Gases


Not every gas in the atmosphere absorbs intensely long-wave radiation from the ground. The greenhouse gases in the earth’s atmosphere are called greenhouse gases, mainly carbon dioxide (CO2), methane, ozone, nitrous oxide, freon and water vapor. They absorb almost all the long-wave radiation emitted from the ground, and only a very narrow region absorbs very little, so they are called “window region”. It is through this window that the earth returns 70% of the heat from the sun to the space in the form of long-wave radiation, thus maintaining the ground temperature unchanged. The greenhouse effect is mainly due to the increase in the number and variety of greenhouse gases by human activities, which makes the 70% value decrease and the remaining heat makes the earth warm.

What is greenhouse gas?

However, although CO2 and other greenhouse gases have a strong ability to absorb long-wave radiation from the ground, their amount in the atmosphere is very small. If the atmospheric state of pressure as a atmospheric pressure and temperature of 0 C is called the standard state, then the whole atmosphere of the earth is compressed to this standard state, its thickness is 8000 meters. At present, the content of CO 2 in the atmosphere is 355 ppm, or 355 parts per million. Converting it to the standard state, it will be 2.8 meters thick. This is 2.8 meters thick in the atmosphere of 8,000 meters thick. Methane content is 1.7 ppm, corresponding to 1.4 cm thick. The ozone concentration is 400 ppb (ppb is one thousandth of ppm), which is only 3 mm thick after conversion. Nitrous oxide is 310 ppb, 2.5 mm thick. There are many kinds of freon, but the most abundant Freon 12 in the atmosphere is only 400 ppt (ppt is one thousandth of ppb), converted to the standard state of only 3 microns. This shows that there are few greenhouse gases in the atmosphere. It is also for this reason that human release without restrictions can easily lead to rapid global warming.

History of development

As early as 1938, British meteorologist Carlinda pointed out that CO2 concentration had risen by 6% since the beginning of the century after analyzing sporadic CO2 observations around the world at the end of the 19th century. He also found that there was a warming tendency in the world from the end of last century to the middle of this century, which caused great repercussions in the world. To this end, Kellin of Scripps Oceanographic Research Institute established an observatory in 1958 at an altitude of 3,400 meters in the Maunaroya Mountains of Hawaii, and began the precise observation of atmospheric CO2 content. Because Hawaii is located in the middle of the North Pacific Ocean. Therefore, it can be considered that it is not affected by terrestrial air pollution and the observation results are reliable.

From April 1958 to June 1991, the atmospheric CO2 concentration in the Maunaroya Mountains was observed. It was found that the atmospheric CO2 content in 1958 was only about 315 ppm, which reached 355 ppm in 1991. The seriousness of the problem also lies in the fact that only about half of the 5.5 billion tons of fossil fuels (about 4 tons of CO2 per ton) that humans burn annually (1996) enter the atmosphere and the rest are mainly absorbed by marine and terrestrial plants. Once the ocean is saturated with CO2, the atmospheric CO2 content will increase exponentially. In addition, they also found seasonal variations in CO2 content, with a difference of 6 ppm between winter and summer. This is mainly due to the winter drought and summer glory of vegetation on the vast continents of the Northern Hemisphere, that is, plants absorb CO2 in summer, which makes the atmospheric CO2 concentration relatively lower.

Includings

According to the determination of CO2 concentration in the air of sealed bubbles in the Antarctic and Greenland continental ice sheets, the CO2 content in the atmosphere has been relatively stable for a long time in the past, about 280 ppm. Only from the mid-18th century, before and after the Industrial Revolution began to rise steadily. That is to say, it took 240 years for human beings to increase the atmospheric CO2 concentration from 280 ppm to 355 ppm.

Methane is the second most important greenhouse gas after CO2. Although its concentration in the atmosphere is much lower than CO2, its growth rate is much higher. According to the Second Climate Change Assessment Report issued by the Intergovernmental Panel on Climate Change (IPCC) in 1996, CO2 increased by 30% in 240 years from 1750 to 1990, while methane increased by 145% in the same period. Methane, also known as biogas, is produced when organic matter decays under anoxic conditions. For example, paddy fields, compost and animal manure all produce biogas. Nitrogen monoxide is also known as laughing gas, because inhaling a certain concentration of this gas can cause facial muscle spasm, which looks like laughing. It is mainly produced by burning fossil fuels and organisms using chemical fertilizers. Although the ozone content in the atmosphere decreases in the stratosphere, it increases in the troposphere, which will be discussed later. Freon gases are compounds of chlorine, fluorine and carbon; they do not exist in nature and are entirely human-made. Because of its low melting point and boiling point, non-flammable, non-explosive, odorless, harmless and excellent stability, it is widely used in the manufacture of refrigerants, foaming agents and cleaners. Although the highest concentrations of Freon 12 and 11 in the earth’s atmosphere are very few, their growth rates have been very high in the past, both of which are 5% per year. Because of its severe destruction of the ozone layer in the atmosphere, its concentration in the atmosphere is expected to decrease gradually from the beginning of the 21st century according to the 1987 International Montreal Protocol.

It should be noted that although the atmospheric concentration of greenhouse gases other than CO2 is much lower than that of CO2, some of them are several orders of magnitude smaller, their greenhouse effect is much stronger than that of CO2. Therefore, their contribution to atmospheric greenhouse effect, according to the second IPCC Report, is only one order of magnitude lower than that of CO2. If their total contribution to the greenhouse effect of the Earth’s atmosphere is small compared with CO2 before 1960, it is not negligible that in the near future they will go hand in hand with CO2 and even exceed CO2.
April 2, 2018, DOE Labor

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