Cyclic Flow of Material: Concepts and Classifications

Abstract

Resource shortages and environmental deterioration are primarily attributed to the disturbance caused by human activities beyond the natural capacity, and the primary purpose of human activity is to satisfy the material and cultural demands of people, which means that the primary object of human activity is “material.” By using material resource processing, transformation, transportation, and other social and economic activities, the service goal of human demands can be satisfied. Therefore, improvement of resources and the environment should first focus on the “material” flow. What is the flow of material? What are the basic laws of material flow? How can we assess the flow state of material? How can we optimize and manage material? These issues are the theoretical basis for the circular economy development and will be discussed separately in the next three chapters.

Appendices

Classroom Discussions and Assignments

4.1.1 Topic for Discussion

The environmental issues of interest were screened by groups in the previous two chapters, and the majorities are closely related to a specific substance circulation; thus, the following are the topics of this chapter: Which material circulation is the most worthy of attention? How are natural and anthropogenic flows conducted? A qualitative description is required.

4.1.2 Example of Topic Selection

Topics can be selected based on the type of material, such as phosphorus or nitrogen in nutrients or heavy metal substances such as lead or cadmium. They can also be selected based on the representative pollutants exposed in the typical regional pollution problems, such as carbon related to global warming and nitrogen related to eutrophication of a lake.

The research protocol can be proposed by each student and shared by learning the research methods in the published thesis. An example of the screening process is shown in Fig. 4.4.

Fig. 4.4

Selection of class discussion issues and process analysis framework

Thesis Title and Introduction Example

4.2.1 Example of a Thesis Title

The following are the requirements for a thesis title defined in the Chinese Core Journals of Environmental Science:

The title should be concise and accurately reflect the content, generally not more than 20 words, see http://www.hjkx.ac.cn/hjkx/. Examples of recommended thesis titles are as follows:

Metal elements content, pollution, and geochemical characteristics of the sediments in the Songhua River.

Effect simulation of the wetland water changes on the calamagrostis angustifolia litter decomposition and nitrogen dynamics.

Study of suspension, sedimentation, and endogenous release of sediment under the action of wind and waves.

The topic should be clearly stated in the thesis along with the research methods and contents.

4.2.2 Thesis Introduction Example

The requirements for an introduction (also called a preface) to a thesis defined in Environmental Science are used for reference. The preface includes the related work of domestic and foreign predecessors (use of a quotation is acceptable) and the purpose, characteristics, and significance of this work. Do not repeat the scientific knowledge.

• (I) Example 1

The following is the Introduction in the thesis “Crossing the ‘environmental mountain’-: discussion of the increase and decrease of the environmental load during economic growth.”

Since the founding of new China, especially the reform and opening to the outside world, China’s economy has continued to grow at a rapid pace and currently has a considerable economic aggregate. Concurrently, the environmental loads have become quite significant, resulting in a grim environmental situation.

In recent years, a series of vital measures in environmental protection have been adopted in China, achieving remarkable results. “The national environmental situation is transformed from the overall deterioration of the environment quality and improvement in part to the basic control of the intensified trend for environmental pollution and improvement of the environment quality in some cities and regions.”

However, because China is still in the process of industrialization and it will be a significant amount of time before the entire process is completed, the method for China to achieve the win-win of economy and environment is the major issue that must be decided now. This is because of the following: (a) The rapid economic growth is likely to continue for many years, and only proper action can avoid the rapid rise of the environmental load; otherwise, China’s environmental problems may be very serious in a few years. (b) China is the largest developing country, with a specific percentage of the world’s total economic and environmental load, which will significantly increase in the future. If the total amount of environmental load cannot be effectively controlled, not only will it affect our country, but it will have a significant impact on the world.

The 16th National Congress of the Communist Party of China indicates that a new industrialization path with good economic returns, low resource consumption, less environmental pollution, and full use of human resources must be initiated.

This contains foresight, provides a grand strategic goal that indicates the forward path for the people of the nation, and is of great significance. The task of environmental protection and economic workers is to provide further detail and execute the new industrialization path.

The view that environment and development must be linked together to identify the essence of the problem has been gradually realized since the 1980s. Recently, a number of monographs have been published both at home and abroad that are of great reference value. For example, the results of model calculations are applied to the literature to provide scenario predictions of world population, resources, and environmental change over the next few decades.

Based on existing literature, this article will discuss the principles of avoiding serious environmental problems in the latter half of the industrialization of our country; perform a necessary theoretical analysis on the increase and decrease of the environmental load during economic growth; use energy consumption as an example to analyze the changes in environmental load during economic growth in some countries and provinces in our country; and forecast the future environmental load of our country.

From: Lu and Mao [5].

• (II) Example 2: an introduction example for a topic that includes new terms

For relatively new research that may involve new terms or vocabulary, the topic must first be interpreted to provide clear meaning of the new terms. For example, the first paragraph in the thesis “Lead in-use stock: a dynamic analysis” follows.

Lead in-use stock refers to the lead currently providing services of various kinds to humanity. It results when more material enters use over time than leaves use. The amount of lead in-use stock for a region or country reflects that regions standard of living under currently available technology, therefore, lead in-use stock is an indicator of the amount of metal that less developed regions may need to put in place to attain comparable material services. Additionally, knowledge of the magnitude of lead in-use stock is useful in estimations of the amount of lead that will be available for future recycling.

From: Mao and Graedel [6].

The introduction should clearly explain why the research should be performed, the current research progress and its significance at home and abroad.