Analysis on voltage characteristics of distribution network considering rolling mill load and Research on control measures

In view of the voltage fluctuation and flicker of distribution network caused by rolling mill type typical load in some distribution networks and the reduction of power quality of power grid, it is necessary to analyze the voltage characteristics of distribution network, and adopt an effective governance measure to suppress harmonics in distribution network and improve power quality of power grid. The mathematical models of several typical loads corrected based on the measured data are established, and the influence radiation range of the corrected rolling mill load model on the distribution network voltage is analyzed, and a SVC (static var compensator) governance measure with SOGI phase-locked strategy is adopted for governance. Finally, combined with the actual operation parameters of a substation of State Grid, the power system simulation model is built by using simulation software, and the effectiveness of the governance measures adopted in this paper is verified by simulation analysis

Comprehensive energy efficiency optimization algorithm for steel load considering network reconstruction and demand response

Abstract Industrial loads are usually energy intensive and inefficient. The optimization of energy efficiency management in steel plants is still in the early stage of development. Considering the topology of power grid, it is an urgent problem to improve the operation economy and load side energy efficiency of steel plants. In this paper, a two-level collaborative optimization method is proposed, which takes into account the dynamic reconstruction cost, transmission loss cost, energy cost and demand response benefit. The upper level objective is the optimization of topology in the grid structure to optimize the power loss and dynamic reconstruction costs of the grid. The lower level is the energy cost considering demand response, real time price and dynamic demand response price. Firstly, the mathematical models of stable load, impact load and the steel production line load are built. The key parameters are identified by the Back Propagation neural network algorithm according to the actual production data. Secondly, considering the constraints of grid structure and load operation capacity, the impact of dynamic grid loss and real-time dynamic electricity price on the energy efficiency of the whole grid are analyzed in depth. The optimal operation model considering the dynamic reconfiguration and grid tramission loss of distribution network is built. Taking a steel plant park in Northeast China as an example, it is proved that the optimization model can improve energy efficiency on the load side by optimizing energy consumption and demand response participation time on load side. The energy cost is reduced by 17.77% on the load side, the network loss is reduced by 1.8%, and the operating cost of the power grid is reduced by 26.2%, which has a positive effect on improving energy utilization efficiency, reducing distribution network loss, and improving overall economic efficiency

Effects of Agronomic Measures on Decomposition Characteristics of Wheat and Maize Straw in China

The utilization of crop straw resources has been highly emphasized by governments and academia in recent decades. The growing importance of straw decomposition in the wheat-maize rotation system and the remarkable diversity of accumulated information on this topic inspired us to quantitatively explore variations in the outcomes of individual studies. We conducted a data analysis of 46 experimental studies reporting the effects of agronomic measures on the straw decomposition rates of wheat (14 studies) and maize (38 studies). Statistical results showed that maize straw crushed and buried in soil with turn-over or rotary tillage can significantly increase straw decomposition rates. Further, with the increase in nitrogen input and straw burial depth in the soil, the maize straw decomposition rate increased significantly, while the amount of straw return showed the opposite trend. Among all agronomic measures in this research, burial depth has demonstrated a significant positive effect on the wheat straw decomposition rate. The random forest analysis identified decomposition time as the most important predictor of straw decomposition rates for wheat and maize. In addition, some agronomic measures and straw decomposition time jointly affect the decomposition rate of straw. In general, agronomic measures are effective factors in controlling straw decomposition in a wheat-maize rotation system

Effects of Agronomic Measures on Decomposition Characteristics of Wheat and Maize Straw in China

The utilization of crop straw resources has been highly emphasized by governments and academia in recent decades. The growing importance of straw decomposition in the wheat-maize rotation system and the remarkable diversity of accumulated information on this topic inspired us to quantitatively explore variations in the outcomes of individual studies. We conducted a data analysis of 46 experimental studies reporting the effects of agronomic measures on the straw decomposition rates of wheat (14 studies) and maize (38 studies). Statistical results showed that maize straw crushed and buried in soil with turn-over or rotary tillage can significantly increase straw decomposition rates. Further, with the increase in nitrogen input and straw burial depth in the soil, the maize straw decomposition rate increased significantly, while the amount of straw return showed the opposite trend. Among all agronomic measures in this research, burial depth has demonstrated a significant positive effect on the wheat straw decomposition rate. The random forest analysis identified decomposition time as the most important predictor of straw decomposition rates for wheat and maize. In addition, some agronomic measures and straw decomposition time jointly affect the decomposition rate of straw. In general, agronomic measures are effective factors in controlling straw decomposition in a wheat-maize rotation system

Effect of Different Cultivation Practices on Soil Physical and Chemical Properties for Greenhouse Vegetables under Long-Term Continuous Cropping

Five kinds of greenhouse vegetables (eggplant, loofah, tomato, cucumber and pepper) were selected in summer uprooting stage from greenhouse in Shouguang area, Shandong Province. Total nitrogen, ammonium nitrogen, nitrate nitrogen, available phosphorus, available potassium, organic matter content and pH, EC value of three soil layers were measured, respectively. The results showed that the total nitrogen, ammonium nitrogen, nitrate nitrogen, available phosphorus and available potassium in the soil were mainly accumulated in the upper soil, which made the soil acidification trend, because different farmers adopted different cultivation practices for different greenhouse vegetables in Shouguang region, but there was no significant effect on soil EC value. The input of ammonium nitrogen and nitrate nitrogen and other related fertilizers to greenhouse cucumber was higher than that of other greenhouse vegetables, but the amount of available potassium fertilizer and organic matter input to greenhouse tomato under different cultivation practices was lower than other greenhouse vegetables. In Shouguang area, the input of organic matter into greenhouse vegetables should be increased by increasing the proportion of manure input to increase the content of soil organic carbon, so as to achieve the balance of carbon and nitrogen ratio, and to provide a scientific basis for the establishment of an evaluation system for the environmental benefits brought about by chemical fertilizer reduction in greenhouse vegetables in Shouguang area

Groundwater Nitrate Contamination and Driving Forces from Intensive Cropland in the North China Plain

High nitrate in groundwater is a serious problem especially in highly active agricultural areas. In this paper, the concentration and spatial distribution of groundwater nitrate in cropland area in the North China Plain were assessed by statistical and geostatistical techniques. Nitrate concentration in groundwater reached a maximum of 526.58 mg/L, and 47.2%, 21.33% and 11.13% of samples had levels in excess of nitrate safety threshold concentration (50 mg/L) in shallow, middle-deep and deep groundwater, respectively. And NO3- content significantly decreased with groundwater depth. Groundwater nitrate concentrations under vegetable area are significantly higher than ones under grain and orchard. And there are great differences in spatial distribution of nitrate in the North China Plain and pollution hotspot areas are mainly in Shandong Province. Based on both multiple regressions combined with principal component analysis (PCA), significant variables for nitrate variation in three types of ground water were found: population per unit area, percentage of vegetable area, percentage of grain crop area, livestock per unit area, annual precipitation and annual mean temperature for shallow groundwater; population per unit area and percentage of vegetable area for middle-deep groundwater; percentage of vegetable area, percentage of grain crop area and livestock per unit area for deep groundwater

An essential role for the hematopoietic transcription factor Ikaros in hypothalamic–pituitary-mediated somatic growth

Ikaros transcription factors play critical functions in the control of lymphohematopoiesis and immune regulation. Family members contain multiple zinc fingers that mediate DNA binding and homooligomerization or heterooligomerization. Ikaros is abundantly expressed in pituitary mammosomatotrophs, where it deacetylates histone 3 sites on the proximal growth hormone (GH) promoter to silence gene expression. Ikaros-null mice display stunted growth with reduced circulating levels of the GH target factor insulin-like growth factor I (IGF-I). Ikaros-deficient mice have small anterior pituitary glands with a disproportionately reduced somatotroph population. Systemic administration of GH results in increased IGF-I levels and enhanced somatic growth. In contrast, reconstitution with WT lymphocytes was not sufficient to rescue the stunted growth phenotype of Ikaros-deficient mice. Ikaros was identified in mouse hypothalamic arcuate nuclei, where it colocalized with GH-releasing hormone (GHRH); in contrast, Ikaros-null mice lack GHRH immunoreactivity in the hypothalamus. Overexpression of Ikaros enhanced GHRH promoter activity and induced endogenous GHRH gene expression. These findings unmask a wider role for Ikaros in the neuroendocrine system, highlighting a critical contribution to the development of the hypothalamic–pituitary somatotrophic axis