Search results

Alternating current (AC) corrosion is a type of corrosion that occurs in buried pipelines under AC stray current interference, which can increase the hydrogen embrittlement sensitivity of pipelines. However, rare research works have been conducted on the hydrogen permeability characteristics of pipeline steel under AC stray current interference. The purpose of this paper is to study hydrogen permeation behavior of X80 steel under AC stray current interference.

In this paper, the hydrogen permeation behavior of X80 steel under AC interference is studied by AC hydrogen charging experiment in a dual electrolytic cell. The relationship between hydrogen evolution rate and hydrogen permeation flux is studied using the gas collection method. The difference between AC hydrogen permeability and direct current (DC) hydrogen permeability is also discussed.

The anodic dissolution caused by AC corrosion promotes the chemical desorption reaction of the adsorbed hydrogen atoms on the surface, reducing the hydrogen atom absorption ratio by 70%. When the AC is smaller than 150░ A/m², the hydrogen permeation process is controlled by the hydrogen atom generation rate, and the hydrogen permeation flux increases with the increase in hydrogen atom generation rate. When the AC exceeds 400░ A/m², the hydrogen permeation process is controlled by the absorption ratio. The hydrogen permeation flux decreases with the decrease in the absorption ratio. Under AC interference, there is a maximum hydrogen permeation flux that linearly correlates to the H⁺ concentration in the solutions.

The high-strength steel is very sensitive to hydrogen embrittlement, and X80 steel has been widely used in oil and gas pipelines. To date, no research has been conducted on the hydrogen permeation behavior of pipeline steel under AC interference, and the hydrogen permeability characteristics of pipeline steel under AC interference are not clear. The research results of this paper are of great significance for ensuring the intrinsic safety of high-strength pipelines under AC stray current interference.

The purpose of this paper is to design intelligent robots operating in such dynamic environments like the RoboCup Middle-Size League (MSL). In the RoboCup MSL, two teams of five autonomous robots play on an 18- × 12-m field. Equipped with sensors and on-board computers, each robot should be able to perceive the environment, make decision and control itself to play the soccer game autonomously.

This paper presents the design of our soccer robots, participating in RoboCup MSL. The mechanical platform, electrical architecture and software framework are discussed separately. The mechanical platform is designed modularly, so easy maintainability is achieved; the electronic architecture is built on industrial standards using PC-based control technique, which results in high robustness and reliability during the intensive and fierce MSL games; the software is developed upon the open-source Robot Operating System (ROS); thus, the advantages of ROS such as modularity, portability and expansibility are inherited.

Based on this paper and the open-source hardware and software, the MSL robots can be re-developed easily to participate in the RoboCup MSL. The robots can also be used in other research and education fields, especially for multi-robot systems and distributed artificial intelligence. Furthermore, the main designing ideas proposed in the paper, i.e. using a modular mechanical structure, an industrial electronic system and ROS-based software, provide a common solution for designing general intelligent robots.

The methodology of the intelligent robot design for highly competitive and dynamic RoboCup MSL environments is proposed.

As the saying goes, “food is heaven of people” the development of agriculture is not only related to the quality of human life but also profoundly affects the efficiency of economic operation. However, under the background of rapid economic and technological development, China’s agricultural modernization process is very slow and incompatible with the development trend of economic modernization. Therefore, it is particularly necessary to innovate the traditional agricultural development model to break through the bottlenecks encountered in the transformation process of agricultural modernization. The proposal of the agricultural logistics ecosphere is to solve the problems of poor industrial linkage, low technical level and backward operation mode in the development process of traditional agriculture, and it is an important starting point for agricultural supply-side structural reform. This study aims to answer three questions in three aspects, namely, what is the agricultural logistics ecosphere, analyzes the general composition of the agricultural logistics ecosphere and how the subjects of the agricultural logistics ecosphere cooperate. It also puts forward suggestions for the coordinated development of the agricultural logistics ecosphere under the leadership of Taoxin. Also, it inspires the transformation of the agricultural development model in other regions and countries.

This study adopts a case study and a qualitative analysis method to collate the first-hand and secondary data obtained from the interview and form a tertiary coding. It explores the mechanism of coordinated development of the agricultural logistics ecosphere from four levels: goal synergy, resource synergy, ability synergy and benefit synergy.

First, the formation of the agricultural logistics ecosphere will not be achieved overnight, as operational management matures and ecosphere experiences the germination-development-mature evolution process. Second, target synergy is the foundation and premise for the formation of agricultural logistics ecosphere: to attract external resources with Taoxin characteristic core resources, to attract external resources to achieve synergy, to provide a guarantee for the realization of the maximum value of the agricultural logistics ecosphere and then to realize the interest synergy of internal and external subjects. Third, driving agricultural products upward in the “10 + 1” model: it is the core resource of the agricultural logistics ecosphere led by Taoxin and attracts external subjects to gather with core resources to further improve the value of the ecosphere. The improvement of the value of the ecosphere can broaden the ecosphere network. This is both an important construction of the ecosphere, and it is also the path choice of the coordinated development of the agricultural logistics ecosphere.

This study has a very important practical value and theoretical significance. In practical terms, the integration of “primary, secondary and tertiary industries” is helpful to foster new momentum for the development of agriculture and rural areas and promote the general framework of the agricultural logistics economy, the analysis of the general mechanism and extension of the transition of the new economy.

This study aims to describe the preparation of antimicrobial material usable in 3D printing of medical devices. Despite the wealth of technological progress at the time of the crisis caused by SARS-CoV-2 virus: Virus that causes current Pandemic situation (COVID-19), the global population had long been exposed beforehand to an acute absence of essential medical devices. As a response, a new type of composite materials intended for rapid prototyping, based on layered silicate saponite (Sap), antimicrobial dye phloxine B (PhB) and thermoplastics, has been recently developed.

Sap was modified with a cationic surfactant and subsequently functionalized with PhB. The hybrid material in powder form was then grounded with polyethylene terephthalate-glycol (PETG) or polylactic acid (PLA) in a precisely defined weight ratio and extruded into printing filaments. The stability and level of cytotoxicity of these materials in various physiological environments simulating the human body have been studied. The applicability of these materials in bacteria and a yeast-infected environment was evaluated.

Ideal content of the hybrid material, with respect to thermoplastic, was 15 weight %. Optimal printing temperature and speed, with respect to maintaining antimicrobial activity of the prepared materials, were T = 215°C at 50 mm/s for PETG/SapPhB and T = 230°C at 40 mm/s for PLA/SapPhB. 3 D-printed air filters made of these materials could keep inner air flow at 63.5% and 76.8% of the original value for the PLA/SapPhB and PETG/SapPhB, respectively, whereas the same components made without PhB had a 100% reduction of airflow.

The designed materials can be used for rapid prototyping of medical devices.

The new materials have been immediately used in the construction of an emergency lung ventilator, Q-vent, which has been used in different countries during the COVID-19 crisis.