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An integrated approach to site-specific management zone delineation

Yuxin MIAO, David J. MULLA, Pierre C. ROBERT

《农业科学与工程前沿（英文）》 2018年第5卷第4期页码 432-441 doi: 10.15302/J-FASE-2018230

摘要：

Dividing fields into a few relatively homogeneous management zones (MZ) is a practical and cost-effective approach to precision agriculture. There are three basic approaches to MZ delineation using soil and/or landscape properties, yield information, and both sources of information. The objective of this study is to propose an integrated approach to delineating site-specific MZ using relative elevation, organic matter, slope, electrical conductivity, yield spatial trend map, and yield temporal stability map (ROSE-YSTTS) and evaluate it against two other approaches using only soil and landscape information (ROSE) or clustering multiple year yield maps (CMYYM). The study was carried out on two no-till corn-soybean rotation fields in eastern Illinois, USA. Two years of nitrogen (N) rate experiments were conducted in Field B to evaluate the delineated MZs for site-specific N management. It was found that in general the ROSE approach was least effective in accounting for crop yield variability (8.0%–9.8%), while the CMYYM approach was least effective in accounting for soil and landscape (8.9%–38.1%), and soil nutrient and pH variability (9.4%–14.5%). The integrated ROSE-YSTTS approach was reasonably effective in accounting for the three sources of variability (38.6%–48.9%, 16.1%–17.3% and 13.2%–18.7% for soil and landscape, nutrient and pH, and yield variability, respectively), being either the best or second best approach. It was also found that the ROSE-YSTTS approach was effective in defining zones with high, medium and low economically optimum N rates. It is concluded that the integrated ROSE-YSTTS approach combining soil, landscape and yield spatial-temporal variability information can overcome the weaknesses of approaches using only soil, landscape or yield information, and is more robust for MZ delineation. It also has the potential for site-specific N management for improved economic returns. More studies are needed to further evaluate their appropriateness for precision N and crop management.

关键词： economically optimum nitrogen rate fuzzy cluster analysis precision nitrogen management site-specific management soil landscape property yield map

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Optimum nitrogen fertilization of

Wentao ZOU,Ruifeng JIA,Jinchang YANG,Rongsheng LI,Guangtian YIN

《农业科学与工程前沿（英文）》 2016年第3卷第4期页码 368-374 doi: 10.15302/J-FASE-2016120

摘要： A greenhouse pot experiment was conducted to study the effects of nitrogen fertilization on seedlings grown with 0, 50, 100, 150, 200, 300, 400 and 600 mg N per seedling according to exponential functions. Seedling height, root collar diameter, leaf area and total biomass increased with increasing fertilization from 0 to 200 mg N per seedling and decreased with further increase in fertilization from 300 to 600 mg N per seedling. The net photosynthetic rate, stomatal conductance, intercellular CO concentration and transpiration rate of seedlings showed a unimodal parabolic trend, with peak values of 7.29 mmol·m ·s , 0.071 mol·m ·s , 220 mmol·mol and 1.34 mmol·m ·s , respectively, when the rate of fertilization was 200 mg N per seedling. Photosynthetic gas exchange parameters were significantly different among nitrogen treatments. Based on the critical values of leaf N and P concentration and N/P ratio, the optimum amount of nitrogen of seedlings was 200–400 mg per seedling for leaf N and P concentration, and 100–400 mg per seedling for N/P ratio. It was concluded that 200–400 mg N per seedling was the most suitable nitrogen range for seedlings.

关键词： Calophyllum inophyllum growth nitrogen fertilization nutrient status photosynthesis

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Size-controllable synthesis of monodispersed nitrogen-doped carbon nanospheres from polydopamine forhigh-rate supercapacitors

《化学科学与工程前沿（英文）》 2023年第17卷第11期页码 1788-1800 doi: 10.1007/s11705-023-2326-8

摘要： Monodispersed nitrogen-doped carbon nanospheres with tunable particle size (100–230 nm) were synthesized via self-polymerization of biochemical dopamine in the presence of hexamethylenetetramine as a buffer and F127 as a size controlling agent. Hexamethylenetetramine can mildly release NH_3, which in turn initiates the polymerization reaction of dopamine. The carbon nanospheres obtained exhibited a significant energy storage capability of 265 F·g^–1 at 0.5 A·g^–1 and high-rate performance of 82% in 6 mol·L^–1 KOH (20 A·g^–1), which could be attributed to the presence of abundant micro-mesoporous structure, doped nitrogen functional groups and the small particle size. Moreover, the fabricated symmetric supercapacitor device displayed a high stability of 94% after 5000 cycles, revealing the considerable potential of carbon nanospheres as electrode materials for energy storage.

关键词： carbon nanospheres size-controlled nitrogen-doped high-rate supercapacitors

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SUSTAINABLE NITROGEN MANAGEMENT FOR VEGETABLE PRODUCTION IN CHINA

《农业科学与工程前沿（英文）》 2022年第9卷第3期页码 373-385 doi: 10.15302/J-FASE-2022455

摘要：

● Sustainable nitrogen management strategies for Chinese vegetable production are summarized.

关键词： enhanced-efficiency nitrogen fertilizer integrated knowledge and products strategy nitrogen rate reactive nitrogen loss vegetable yield

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Circulating fluidized bed biological reactor for nutrients removal

CUI Yubo, LIU Hongbo, BAI Chunxue

《环境科学与工程前沿（英文）》 2008年第2卷第3期页码 349-353 doi: 10.1007/s11783-008-0051-7

摘要： A new biological nitrogen removal process, which is named herein “The circulating fluidized bed bioreactor (CFBBR)”, was developed for simultaneous removal of nitrogen and organic matter. This process was composed of an anaerobic bed (Riser), aerobic bed (Downer) and connecting device. Influent and nitrified liquid from the aerobic bed enters the anaerobic bed from the bottom of the anaerobic bed, completing the removal of nitrogen and organic matter. The system performance under the conditions of different inflow loadings and nitrified liquid recirculation rates ranging from 200% to 600% was examined. From a technical and economic point of view, the optimum nitrified liquid recirculation rate was 400%. With a shortest total retention time of 2.5 h (0.8 h in the anaerobic bed and 1.5 h in the aerobic bed) and a nitrified liquid recirculation rate of 400% based on the influent flow rate, the average removal efficiencies of total nitrogen (TN) and soluble chemical oxygen demand (SCOD) were found to be 88% and 95%, respectively. The average effluent concentrations of TN and SCOD were 3.5 mg/L and 16 mg/L, respectively. The volatile suspended solid (VSS) concentration, nitrification rate and denitrification rate in the system were less than 1.0 g/L, 0.026–0.1 g NH-N/g VSSd, and 0.016–0.074 g NO-N/g VSSd, respectively.

关键词： soluble chemical bioreactor biological nitrogen optimum nitrified nitrogen removal

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REGIONAL ASSESSMENT OF SOIL NITROGEN MINERALIZATION IN DIVERSE CROPLAND OF A REPRESENTATIVE INTENSIVE

《农业科学与工程前沿（英文）》 2023年第10卷第4期页码 530-540 doi: 10.15302/J-FASE-2023515

摘要：

Soil nitrogen mineralization (N_min) is a key process that converts organic N into mineral N that controls soil N availability to plants. However, regional assessments of soil N_min in cropland and its affecting factors are lacking, especially in relation to variation in elevation. In this study, a 4-week incubation experiment was implemented to measure net soil N_min rate, gross nitrification (Nit) rate and corresponding soil abiotic properties in five field soils (A–C, maize; D, flue-cured tobacco; and E, vegetables; with elevation decreasing from A to E) from different altitudes in a typical intensive agricultural area in Dali City, Yunnan Province, China. The results showed that soil N_min rate ranged from 0.10 to 0.17 mg·kg⁻¹·d⁻¹ N, with the highest value observed in field E, followed by fields D, C, B, and A, which indicated that soil N_min and Nit rates varied between fields, decreasing with elevation. The soil Nit rate ranged from 434.2 to 827.1 µg·kg⁻¹·h⁻¹ N, with the highest value determined in field D, followed by those in fields E, C, B, and A. The rates of soil N_min and Nit were positively correlated with several key soil parameters, including total soil N, dissolved organic carbon and dissolved inorganic N across all fields, which indicated that soil variables regulated soil N_min and Nit in cropland fields. In addition, a strong positive relationship was observed between soil N_min and Nit. These findings provide a greater understanding of the response of soil N_min among cropland fields related to spatial variation. It is suggested that the soil N_min from cropland should be considered in the evaluation of the N transformations at the regional scale.

关键词： cropland gross nitrification rate regulatory factors soil nitrogen mineralization spatial variation

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Reconsideration on the effect of nitrogen on mixed culture polyhydroxyalkanoate production toward high

Zhiqiang Chen, Lizhi Zhao, Ye Ji, Qinxue Wen, Long Huang

《环境科学与工程前沿（英文）》 2019年第13卷第4期 doi: 10.1007/s11783-019-1135-2

摘要：

Effect of nitrogen on mixed culture PHA production was reconsidered.

Enrichment history of PHA accumulating culture was discussed.

Higher PHA content and biomass growth were achieved in presence of nitrogen.

Enrichment strategy toward higher PHA accumulation was investigated.

Microbial community succession in PHA accumulation phase was investigated.

关键词： Polyhydroxyalkanoate (PHA) Organic loading rate Nitrogen content Biomass growth Enrichment history

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Experimental study on performance of passive and active solar stills in Indian coastal climatic condition

R. LALITHA NARAYANA, V. RAMACHANDRA RAJU

《能源前沿（英文）》 2020年第14卷第1期页码 105-113 doi: 10.1007/s11708-018-0536-4

摘要： This present work is aimed to examine the effect of mass flow rate on distillate output and performance of a solar still in active mode. Outdoor experiments were conducted at the coastal town, Kakinada (16° 93′N/83° 33′E), Andhra Pradesh, India. A solar still with a 30° of fixed cover inclination, 1m of effective basin area, and a flat-plate collector (FPC) with an effective area of 2 m were used. An attempt was also made earlier in passive mode to optimize the water depth for the same solar still for maximum yield and distillation efficiency. For the passive still, it is observed that the capacity of heat storage and heat drop are significant parameters that affect the still performance. For the selected still design, the study reveals that 0.04 m water depth is the optimum value for specific climatic conditions. In the active solar still, with the optimum water depth, different flow rates of 0.5, 1 and 1.5 L/min are considered through FPC. It is observed that both the mass flow rate and the variation of internal heat transfer coefficients with the mass flow rate have a significant effect on the yield and performance of the still. The experimental results show that the combination of 1.5 L/min mass flow rate and an optimum water depth of 0.04m leads to a maximum yield for the active solar still. The enhanced yield of the active solar still is 57.55%, compared with that of the passive solar still, due to increase in area of radiation collection and more heat absorption rate.

关键词： distillation efficiency solar still heat transfer coefficient water depth optimum and mass flow rate

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Recent advances in understanding genetic variants associated with economically important traits in sheep

Song-Song XU, Meng-Hua LI

《农业科学与工程前沿（英文）》 2017年第4卷第3期页码 279-288 doi: 10.15302/J-FASE-2017151

摘要： Sheep are one of the most economically important domesticated animals for human society. However, genetic improvements for the key traits associated with meat, growth, milk, wool, reproduction, horns and tails progress slowly using conventional crossbreeding methods. With the development and utilization of high-throughput screening technologies over the last decade, a list of functional genes and genetic variants associated with these traits has been identified. This review covers recent genome-wide studies on sheep productive traits using high-throughput screening technologies, including those based on single-nucleotide polymorphisms and copy number variants at the whole-genome level (e.g., genome-wide association studies), transcriptome and DNA methylation sequences. Additionally, comprehensive information on functional genes and genetic variants associated with economically important traits in sheep is provided.

关键词： sheep high-throughput screening productive traits genome-wide studies

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旅客机环境控制系统优化研究

方林,王浚

《中国工程科学》 2006年第8卷第1期页码 77-80

摘要：

为了选择经济高效的旅客机环境控制系统，对现役各种旅客机采用的环境控制系统方案进行了优化设计和比较，分别建立了二轮简单式低压除水系统、三轮升压式高压除水系统和四轮升压式高压除水系统（又称冷凝循环制冷系统）的优化设计数学模型，以起飞燃油质量代偿损失为目标函数，采用广义乘子法结合单纯形加速法求解，优化结果可作为设计研究旅客机环境控制系统的理论依据。

关键词：旅客机环境控制优化设计

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系统非优分析理论及方法

何平

《中国工程科学》 2003年第5卷第7期页码 40-46

摘要：

对系统非优分析理论做了较为详细的论述。指出寻求不确定系统优化的主要问题，关键是缺少对系统的非优分析。在系统非优范畴的基础上建立了征兆群与经验分析，提出了系统非优度量以及从非优追踪到系统自组织等问题。

关键词：系统非优范畴非优征兆群非优度量系统自组织

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Determining the optimum economic insulation thickness of double pipes buried in the soil for district

Fating LI, Pengfei JIE, Zhou FANG, Zhimei WEN

《能源前沿（英文）》 2021年第15卷第1期页码 170-185 doi: 10.1007/s11708-020-0680-5

摘要： The insulation thickness (IT) of double pipes buried in the soil (DPBIS) for district heating (DH) systems was optimized to minimize the annual total cost of DPBIS for DH systems. An optimization model to obtain the optimum insulation thickness (OIT) and minimum annual total cost (MATC) of DPBIS for DH systems was established. The zero point theorem and fsolve function were used to solve the optimization model. Three types of heat sources, four operating strategies, three kinds of insulation materials, three buried depth (BD) values, and seven nominal pipe size (NPS) values were considered in the calculation of the OIT and MATC of DPBIS for DH systems, respectively. The optimization results for the above factors were compared. The results show that the OIT and MATC of DPBIS for DH systems can be obtained by using the optimization model. Sensitivity analysis was conducted to investigate the impact of some economic parameters, i.e., unit heating cost, insulation material price, interest rate, and insulation material lifetime, on optimization results. It is found out that the impact of sensitivity factors on the OIT and MATC of DPBIS for DH systems is different.

关键词： double pipes optimization model optimum insulation thickness minimum annual total cost

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Estimation of optimum design of structural systems via machine learning

《结构与土木工程前沿（英文）》 2021年第15卷第6期页码 1441-1452 doi: 10.1007/s11709-021-0774-0

摘要： Three different structural engineering designs were investigated to determine optimum design variables, and then to estimate design parameters and the main objective function of designs directly, speedily, and effectively. Two different optimization operations were carried out: One used the harmony search (HS) algorithm, combining different ranges of both HS parameters and iteration with population numbers. The other used an estimation application that was done via artificial neural networks (ANN) to find out the estimated values of parameters. To explore the estimation success of ANN models, different test cases were proposed for the three structural designs. Outcomes of the study suggest that ANN estimation for structures is an effective, successful, and speedy tool to forecast and determine the real optimum results for any design model.

关键词： optimization metaheuristic algorithms harmony search structural designs machine learning artificial neural networks

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Unified cycle model of a class of internal combustion engines and their optimum performance characteristics

Shiyan ZHENG

《能源前沿（英文）》 2011年第5卷第4期页码 367-375 doi: 10.1007/s11708-011-0170-x

摘要： The unified cycle model of a class of internal combustion engines is presented, in which the influence of the multi-irreversibilities mainly resulting from the adiabatic processes, finite-time processes and heat leak loss through the cylinder wall on the performance of the cycle are taken into account. Based on the thermodynamic analysis method, the mathematical expressions of the power output and efficiency of the cycle are calculated and some important characteristic curves are given. The influence of the various design parameters such as the high-low pressure ratio, the high-low temperature ratio, the compression and expansion isentropic efficiencies etc. on the performance of the cycle is analyzed. The optimum criteria of some important parameters such as the power output, efficiency and pressure ratio are derived. The results obtained from this unified cycle model are very general and useful, from which the optimal performance of the Atkinson, Otto, Diesel, Dual and Miller heat engines and some new heat engines can be directly derived.

关键词： internal combustion engine irreversibility power output efficiency optimization