scholarly journals Calculation of Comprehensive Ecological Flow with Weighted Multiple Methods Considering Hydrological Alteration

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1212 ◽  
Author(s):  
Zhenxiang Xing ◽  
Yinan Wang ◽  
Xinglong Gong ◽  
Jingyan Wu ◽  
Yi Ji ◽  
...  
Keyword(s):  
Water Requirement ◽  
Hydrological Process ◽  
The Sanjiang Plain ◽  
Flow Calculation ◽  
Hydrological Alteration ◽  
Ecological Water Requirement ◽  
Study Results ◽  
Runoff Series ◽  
Ecological Flow ◽  
Calculation Results

Instream ecological flow is an essential determinant of river health. Intra- and interannual distribution characteristics of runoff have been altered to different degrees by dam construction. Historical runoff series with alterations, as basic data for ecological flow calculation, provide minimal instream hydrological process information, which affects the credibility of calculation results. Considering the influence of the alterations in runoff series on ecological flow calculation, the Gini coefficient (GI) is introduced to study the evenness degrees of the intra-annual runoff distribution of four hydrological stations located in the Naolihe basin of the Sanjiang Plain. The hydrological alteration diagnosis system is used to examine the alteration points in the GI series of each hydrological station for selecting reasonable subsequences. Based on the selected subsequences, the ecological flow of each station is calculated using three hydrological methods, and the comprehensive ecological flow is calculated using weighted calculation results from the three hydrological methods. The study results show that ecological flow and natural flow have similar processes with two peaks occurring in the process in May and August, respectively. Also, dams decrease the ecological water requirement damage frequency in dry seasons, but overuse of water resources increases the ecological water requirement damage frequency in flood seasons.

scholarly journals Ecological Water Requirement in Upper and Middle Reaches of the Yellow River Based on Flow Components and Hydraulic Index

2021 ◽  
Vol 18 (20) ◽  
pp. 10956
Author(s):  
Shibao Lu ◽  
Wenting Cai ◽  
Wei Shao ◽  
Farhad Taghizadeh-Hesary ◽  
Muhammad Faisal ◽  
...  
Keyword(s):  
Yellow River ◽  
Research Result ◽  
Water Requirement ◽  
Actual Condition ◽  
The Yellow River ◽  
Flow Process ◽  
Ecological Water Requirement ◽  
Ecological Flow ◽  
Flow Components ◽  
Regulation Model

Deterioration of the ecological environment in the upper and middle reaches of the Yellow River in China substantially impacts the growth and development of aquatic organisms in the drainage basin. This paper builds a conceptual model by applying flow components and fish ecological requirements relation with a relevant object of main fish in the upper and middle reaches of the Yellow River. The paper utilized the flow restoration method by employing the River2D model (two-dimensional model of river hydrodynamics and fish habitat), and a one-dimensional hydrodynamics HEC-RAS (hydrologic engineering center’s-river analysis system). The calculation result showed that the runoff condition required for Silurus lanzhouensis survival is that the monthly lowest flow in a year is 150 m3·s−1, and the lowest flow for suitable flow from April to October is 150 m3·s−1, and 300 m3·s−1 from November to March. The research result is closer to the actual condition and has more outstanding operability. Meanwhile, the results proposed the coupling method of ecological water requirement for the mainstream of the Yellow River. Moreover, the results portrayed the ecological flow process according to the upper envelope of minimum and maximum ecological water requirements of each fracture surface. It is regarded that the ecological flow process is deemed as the initial value of the reservoir regulation model.

scholarly journals Hydraulic method to determine the ecological flow for fish

2018 ◽  
Vol 246 ◽  
pp. 01110
Author(s):  
Jun Yan ◽  
Xuewei Fu ◽  
chengwei Tian ◽  
Zhenyu Yang ◽  
Qingyan Liu
Keyword(s):  
Reference Value ◽  
Water Requirement ◽  
Time And Space ◽  
Living Space ◽  
Hydraulic Method ◽  
Ecological Protection ◽  
Ecological Water Requirement ◽  
Social And Economic Development ◽  
Ecological Flow ◽  
Ecological Problems

Social and economic development will influence the nature environment and lead to ecological problems, among which the ecological flow concerns the food chain and fish populations. Although there are many computation formulas for counting ecological flow, it is very difficult to unite and get reasonable values. According to the existing research of ecological flow, the concept and calculation method of ecological flow are analyzed, which shows that in a complex ecological system, ecological water requirement is difficult to meet the requirements of all the protection object of water requirement at the same time. Therefore, we should focus on the specific fish with reference value to build ecological protection object and determine the ecological flow. Furthermore, the ecological flow should be the regulation of water quality and water quantity in time and space. Using hydraulic method, the fish living space under different water flow environments can be determined, and specific time and space regulation schemes can be obtained.

Analysis of Characteristics of Halogen and LED Automobile Lamps

2020 ◽  
pp. 57-62
Author(s):  
Olga Yu. Kovalenko ◽  
Yulia A. Zhuravlyova
Keyword(s):  
Power Consumption ◽  
Flip Chip ◽  
Weather Conditions ◽  
Luminous Flux ◽  
Luminous Efficacy ◽  
Colour Temperature ◽  
Study Results ◽  
Calculation Results ◽  
Mandatory Rules ◽  
Halogen Lamps

This work contains analysis of characteristics of automobile lamps by Philips, KOITO, ETI flip chip LEDs, Osram, General Electric (GE), Gtinthebox, OSLAMPledbulbs with H1, H4, H7, H11 caps: luminous flux, luminous efficacy, correlated colour temperature. Characteristics of the studied samples are analysed before the operation of the lamps. The analysis of the calculation results allows us to make a conclusion that the values of correlated colour temperature of halogen lamps are close to the parameters declared by manufacturers. The analysis of the study results has shown that, based on actual values of correlated colour temperature, it is not advisable to use LED lamps in unfavourable weather conditions (such as rain, fog, snow). The results of the study demonstrate that there is a slight dispersion of actual values of luminous flux of halogen lamps by different manufacturers. Maximum variation between values of luminous flux of different lamps does not exceed 14 %. The analysis of the measurement results has shown that actual values of luminous flux of all halogen lamps comply with the mandatory rules specified in the UN/ECE Regulation No. 37 and luminous flux of LED lamps exceeds maximum allowable value by more than 8 %. Luminous efficacy of LED lamps is higher than that of halogen lamps: more than 82 lm/W and lower power consumption. The results of the measurements have shown that power consumption of a LED automobile lamp is lower than that of similar halogen lamps by 3 times and their luminous efficacy is higher by 5 times.

Excimer Laser Amorphous Silicon Film Crystallization: A Study of Time Resolved Reflectivity Measurements

1993 ◽  
Vol 297 ◽  
Author(s):  
C. Summonte ◽  
M. Bianconi ◽  
D. Govoni
Keyword(s):  
Heat Flow ◽  
Amorphous Silicon ◽  
Silicon Film ◽  
Optical Simulation ◽  
Molten Layer ◽  
Time Resolved ◽  
Flow Calculation ◽  
Explosive Crystallization ◽  
Bulk Nucleation ◽  
Calculation Results

Time Resolved Reflectivity during XeCl pulsed laser irradiation of amorphous silicon films deposited on glass was measured. Simulation of the process by a Heat Flow Calculation in which explosive crystallization was not forced to occur, predicts the coexistence of partial bulk nucleation and a traveling molten layer. Optical simulation of Time Resolved Reflectivity was used to critically examine the Heat Flow Calculation results, substantially confirming the existence of a mixture of thermodynamical phases.

scholarly journals Eco-environmental water requirements in Shuangtaizi Estuary Wetland based on multi-source remote sensing data

2018 ◽  
Vol 9 (2) ◽  
pp. 338-346
Author(s):  
Qian Cheng ◽  
Lin fei Zhou ◽  
Tie liang Wang
Keyword(s):  
Remote Sensing ◽  
Remote Sensing Data ◽  
Environmental Water ◽  
Water Requirement ◽  
Water Requirements ◽  
Sensing Data ◽  
Ecological Water Requirement ◽  
Development And Utilization ◽  
Environmental Requirements ◽  
Wetland Resources

Abstract With rapid economic development and expansion of urban boundaries, increasingly damaged wetland resources have seriously threatened the ecosystem. The study of eco-environmental requirements of wetlands is not only the basis of water resources allocation in development and utilization, but also for creating a sustainable system to maintain and improve the overall ecosystem. In this study, we used the Shuangtaizi Estuary Wetland as our study area. The breakdown of wetland cover types was extracted based on multi-source remote sensing data, providing the graphic database for ecological water requirement calculation. According to the characteristics of the Shuangtaizi Estuary Wetland ecosystem, the methods of quantifying the components of ecological water requirements were determined. The results showed that the optimum ecological water requirement of the total wetland was 239 million m3. The minimum, 75th percentile frequency, and 95th percentile frequency water requirements were 670 million m3, 921 million m3, and 1,078 million m3, respectively.

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