Evaluation of Alpha-Ketoglutarate Supplementation on the Improvement of Intestinal Antioxidant Capacity and Immune Response in Songpu Mirror Carp (Cyprinus carpio) After Infection With Aeromonas hydrophila

As an intermediate substance of the tricarboxylic acid cycle and a precursor substance of glutamic acid synthesis, the effect of alpha-ketoglutarate on growth and protein synthesis has been extensively studied. However, its prevention and treatment of pathogenic bacteria and its mechanism have not yet been noticed. To evaluate the effects of alpha-ketoglutarate on intestinal antioxidant capacity and immune response of Songpu mirror carp, a total of 360 fish with an average initial weight of 6.54 ± 0.08 g were fed diets containing alpha-ketoglutarate with 1% for 8 weeks. At the end of the feeding trial, the fish were challenged with Aeromonas hydrophila for 2 weeks. The results indicated that alpha-ketoglutarate supplementation significantly increased the survival rate of carp after infection with Aeromonas hydrophila (P < 0.05), and the contents of immune digestion enzymes including lysozyme, alkaline phosphatase and the concentration of complement C4 were markedly enhanced after alpha-ketoglutarate supplementation (P < 0.05). Also, appropriate alpha-ketoglutarate increased the activities of total antioxidant capacity and catalase and prevented the up-regulation in the mRNA expression levels of pro-inflammatory cytokines including tumor necrosis factor-α, interleukin-1β, interleukin-6, and interleukin-8 (P < 0.05). Furthermore, the mRNA expression levels of toll-like receptor 4 (TLR4), and nuclear factor kappa-B (NF-κB) were strikingly increased after infection with Aeromonas hydrophila (P < 0.05), while the TLR4 was strikingly decreased with alpha-ketoglutarate supplementation (P < 0.05). Moreover, the mRNA expression levels of tight junctions including claudin-1, claudin-3, claudin-7, claudin-11 and myosin light chain kinases (MLCK) were upregulated after alpha-ketoglutarate supplementation (P < 0.05). In summary, the appropriate alpha-ketoglutarate supplementation could increase survival rate, strengthen the intestinal enzyme immunosuppressive activities, antioxidant capacities and alleviate the intestinal inflammation, thereby promoting the intestinal immune responses and barrier functions of Songpu mirror carp via activating TLR4/MyD88/NF-κB and MLCK signaling pathways after infection with Aeromonas hydrophila

Influence of CDFW Process Parameters on Microstructure and Mechanical Properties of U75V Rail Steel Welded Joint

In the present paper, the continuous-drive friction welding (CDFW) technology has been successfully applied to join the U75V rail steel. The base metal (BM) of U75V rail steel is lamellar pearlite, and the weld zone could be clearly divided into three subzones (i.e., heat affected zone, thermo-mechanical affected zone (TMAZ), and central weld zone (CWZ)). Electron back-scattered diffraction examinations revealed the martensitic evolution in TMAZ and CWZ, suggesting that the experienced high temperature, severe plastic deformation, and fast cooling rate induce the microstructure transition during the CDFW process. The hard and brittle martensite structure explains the raised microhardness profiles and the reduced impact absorption energy of the as-welded joints. The CDFW process parameters govern the joint properties via influencing the welding heat input and plastic deformation by spindle speed and friction pressure at the friction stage, and the plastic deformation layer (flash) extrusion by upsetting pressure at the upsetting stage. More favorable results could be obtained at small set values of spindle speed (1800 rpm) and friction pressure (75 MPa) with less heat input and plastic deformation, and a large set value of upsetting pressure (175 MPa) with more flash extrusion, whose tensile strength reached 94.3% of that of the BM

Research on the Application and Control Strategy of Energy Storage in Rail Transportation

With the development of the global economy and the increase in environmental awareness, energy technology in transportation, especially the application of energy storage technology in rail transportation, has become a key area of research. Rail transportation systems are characterized by high energy consumption and poor power quality due to the more flexible regulation capability of energy storage technology in these aspects. This paper summarizes the latest research results on energy storage in rail transportation systems, matches the characteristics of energy storage technologies with the energy storage needs of rail transportation, and analyzes the operation of energy storage systems in different scenarios. The adaptability of batteries, supercapacitors, and flywheels as energy storage systems for rail transportation is summarized and compared. The topologies and integration methods of various energy storage systems are studied. The control strategies under each control of rail transportation are summarized and proposed. The future development direction of energy storage system for rail transportation prospects and the corresponding reference is provided for the engineering of energy storage technology in the field of rail transportation

Study on Dynamic Performance Parameters of Laser Tracker Based on Self-Developed Circular Trajectory Generator System

The laser tracker has characteristics of high measurement accuracy and wide measurement range. Laser tracker technology, as an effectively large-scale measuring approach, plays a critical role in dynamic measurement. Currently, the static performance of laser trackers has been well studied. However, the dynamic characteristics of the laser tracker remain unclear in terms of evaluating its dynamic performance. The circular trajectory generator measurement system can quantify the dynamic performance of the laser tracker. We developed a standard circular trajectory generator using a stable servo system and then conducted an in-depth study on the dynamic performance of the laser tracker through statistical analysis. Numerous experiments have shown that if the laser tracker is set at equal spacing, the dynamic indication error is smallest when the measurement distance is 3 m, indicating that the fitted diameter at a distance of 3 m is closest to the diameter of the circular trajectory generator. If the laser tracker is set with equal sampling frequency, the dynamic indication error is smallest when the measurement distance is 5 m. When the circular trajectory generator is at low speed, the measurement spacing of sampling points of the laser tracker is fixed proportional to the number of measurement points, while at low or high speed the sampling frequency of the laser tracker is fixed proportionally to the number of measurement points. These conclusions will facilitate the application of the laser tracker in dynamic measurement

A Range-Extension Method for an Indoor Standard Device for Large-Scale Length Measurement

The Laser interferometer plays an important role in the field of geometrics for large-size measuring applications. Its linear displacement error can be traced from indoor large-scale standard devices. However, the measuring range of the indoor large-scale standard device is too limited to meet the full range measurement of the laser interferometer. So, the lack of accuracy of the results is one of the key issues of laser interferometers. To solve this problem, the corner reflector is used to extend the range of indoor large-scale standard devices, which meet the indication errors in the effective measuring range of the laser interferometer. The range-extension method not only doubles the effective measuring range, but also provides a way to trace the source of other large-size measuring instruments. This work proposes a significant solution to the field of length measurement

Research on Demand Analysis and Optimal Allocation of Rail Transit Hybrid Energy Storage Based on the Electric Traction Model

With the development of power transmission technology and power electronics, electrified railroads are widely used and pose a great challenge for the power grid. Hybrid energy storage integrates different advantages of multiple energy storage and can cope with the complex energy situation of rail transit. The complementary characteristics of lithium batteries and flywheels in terms of techno-economic indicators make them the main form of hybrid energy storage. In this paper, we analyze the power demand during train operation by studying the electromechanical characteristics of the rail transit traction process. On this basis, hybrid energy storage is configured to meet the power demand, and particle swarm optimization is chosen as the solution tool to perform the capacity configuration of lithium battery and flywheel in this paper. Finally, this paper proves the feasibility of the proposed theory by arithmetic example analysis, and it is shown that the proposed scheme can achieve a high percentage of energy reuse and low application cost

Research on Demand Analysis and Optimal Allocation of Rail Transit Hybrid Energy Storage Based on the Electric Traction Model

With the development of power transmission technology and power electronics, electrified railroads are widely used and pose a great challenge for the power grid. Hybrid energy storage integrates different advantages of multiple energy storage and can cope with the complex energy situation of rail transit. The complementary characteristics of lithium batteries and flywheels in terms of techno-economic indicators make them the main form of hybrid energy storage. In this paper, we analyze the power demand during train operation by studying the electromechanical characteristics of the rail transit traction process. On this basis, hybrid energy storage is configured to meet the power demand, and particle swarm optimization is chosen as the solution tool to perform the capacity configuration of lithium battery and flywheel in this paper. Finally, this paper proves the feasibility of the proposed theory by arithmetic example analysis, and it is shown that the proposed scheme can achieve a high percentage of energy reuse and low application cost

Research on the Frequency Regulation Characteristics and Control Strategy of Wind Power Generation with Energy Storage Synergy

With the high penetration of wind power, the power system has put forward technical requirements for the frequency regulation capability of wind farms. Due to the energy storage system’s fast response and flexible control characteristics, the synergistic participation of wind power and energy storage in frequency regulation is valuable for research. This paper established a frequency characteristic model of a power system, including wind power and energy storage, and analyzed the influence of different frequency regulation methods on system stability. Based on the established model, a fuzzy PID-based energy management strategy was designed for different disturbance scenarios, which offered the advantages of simple parameter design and easy online operation of the project. This paper used a case based on the actual parameters for verification. The energy storage, rated at 10% of the wind farm’s rated power, provided 56% frequency drop suppression and 89% frequency fluctuation rate suppression, according to the proposed model in this paper. The proposed fuzzy PID control strategy achieved adaptive control of the controller parameters under strong disturbances and was able to provide an additional frequency rejection capability of 10–25%