直径1422 mm X80管道环焊接头应变能力数值模拟方法

鉴于高钢级管材的组织特征及焊缝失效对于管道安全的重要影响,管道环焊缝承载能力成为当前管道行业的研究热点,以中俄东线全自动焊口为研究对象,准确考虑环焊接头根焊、热影响区、母材、填充焊4个区域材料本构关系的差异性,基于有限元方法建立了分析管道环焊接头应变能力的数值仿真模型。定量分析了母材屈强比、运行内压、载荷类型等组合工况下焊缝强度匹配系数等对管道环焊缝裂纹扩展驱动力的影响。采用静裂纹起裂的失效判定方法,以表观断裂韧性值为临界准则,结合中俄东线管材及环焊接头材料特性参数实际变化范围,计算了在设计工况范围内最不利条件下中俄东线环焊接头的应变能力。结果表明:提高焊缝区强度匹配能够有效减小接头的裂纹扩展驱动力,增加管道内压或提高母材屈强比会使相同强度匹配条件下的裂纹扩展驱动力更大,拉伸载荷下的裂纹扩展驱动力要大于弯曲载荷下的裂纹扩展驱动力。该方法既可以用于根据焊接接头性能要求指导焊接参数的确定,也可以用于在役管道含缺陷焊接接头的适用性评价。     

中俄东线天然气管道跨国计量站配置及运行现状

中俄东线天然气管道作为一条大规模跨国输气管道,其贸易计量站的技术与管理水平,将直接影响中俄双方的经济利益。中俄东线天然气贸易计量由3套计量系统组成,其中主计量系统与核查计量系统安装在俄罗斯布拉格维申斯克计量站,比对计量系统安装在中国黑河计量站,俄罗斯两套计量系统的运行参数均实时传输至黑河计量站,使其能够对境内外3套计量系统进行全方位监控,通过对比3套系统的计量结果,最终确定贸易结算气量。根据中俄两国签订的《天然气计量协议》中对气体质量参数的规定,在两国计量站均配置了气质分析设备,且俄罗斯计量站所有气质分析设备的检测结果均实时传输至黑河计量站。通过对黑河计量站实行智慧化建设,不但降低了计量站站控系统调试对计量系统的影响,而且实现了远程诊断及流程切换的智能化。基于计量站运行现状,提出如下建议:①在运行过程中增加对自动化逻辑的测试,并联合自动化专业公司对系统的使用情况进行试验测试,以达到简化控制逻辑、提高系统稳定性的目的;②加大对技术人员的培训与考核,以提高计量站的运行管理水平。(图2,表4,参22)     

Fluorimetric studies of the interactions of wheat puroindolines with polar lipids on the surface starch granules

The interactions of puroindolines with polar lipids were investigated using polarization of fluorescence probes preincorporated into a liposomal bilayer containing PC, PI, PS, MGDG, DGDG, and sulfolipids. The intrinsic fluorescence of Trp residue method was also used. Regardless of the kind of lipid used for liposome preparation, proteins interacted with the liposomes. Conformational changes of the proteins were observed simultaneously with the change in the molecule packing in the lipid bilayer of the liposomes. Puroindoline interactions with the surface of the liposomes have explicit importance for the net charge of this surface. The strong interaction between the proteins and lipids takes place in the presence of a ligand with a negative charge. The obtained results confirm that lipids take part in puroindoline–starch granule surface interactions.     

Effects of Various Phytohormones On Haploid Wheat Production in Wheat x Maize Crosses

Abstract

The Effects of Phytohormones On The Production of Haploid Wheat Were Examined in The intergeneric Crosses Between Japanese Wheat Cultivar (Triticum Aestivum Cv. Zenkojikomugi) and Maize (ZEA MAYS Cv. Pioneer P80 Lisa). The Detached Wheat Spikes Pollinated With Maize Were Cultured in A Solution Containing Sucrose and Sulfurous Acid Supplemented With 2,4―Dichlorophenoxyacetic Acid (2,4―D), indole-Acetic Acid, Naphthalene Acetic Acid, Kinetin Or 6-Benzylaminopurine At 0, 0.1, 1, 10, 100 Or 1000 Mg L-¹. Haploid Embryos Obtained Were Cultured On Agarose-Solidified B5 Medium. The Frequency of Plant Regeneration Was Significantly Affected Only By The Treatment With 100 Mg L-¹ 2,4―D. Thus, The Detached Spikes Were Cultured in The Medium Containing 2,4―D At 0, 25, 50, 75, 100, 125, 150, 175, 200 Or 400 Mg L-¹. The Treatments With 50 Mg L-¹ 2,4―D increased The Embryo Size, But The Treatments With Above 75 Mg L-¹ 2,4―D inhibited The Development of The Embryo. The Percentage of Florets Developing into Haploid Plants Was increased By The Treatment With 100 Mg L-¹ 2,4―D. Therefore, The Concentration of 2,4―D in THe Spikes Treated With 2,4―D At 50, 100 and 150 Mg L-¹ WERe Measured By Gas Chromatography. The Concentration of 2,4―D in THE Seed Was increased To 9.24 Ppm By The Treatment With 100 Mg L-¹ 2,4―D, A Further increase of 2,4―D Concentration in The Medium Having No Effect. On The Other Hand, The Concentration of 2,4―D in The Glumes and Rachis increased Up To 12.72 and 41.55 Ppm By The TreatmenT With 100 and 150 Mg L-¹ 2,4―D, Respectively. The Treatments With 2,4―D At A Concentration Higher Than 100 Mg L-¹ inhibited Embryo Development. The Present Results Suggested That 2,4―D At The Concentrations From 50 To 100 Mg L-¹ Would Be Optimum For Haploid Wheat Production Using Maize.     

Inheritance of C3―C4 Intermediate Photosynthesis in Reciprocal Hybrids Between Moricandia Arvensis (C3―C4) and Brassica Oleracea (C3) That Differ in Their Genome Constitution

Abstract

To Elucidate The Genetic Mechanisms Underlying C₃―C₄ intermediate Photosynthesis, We investigated The Structural and Photosynthetic Characteristics of Leaves of Reciprocal Hybrids Between The C₃―C₄ intermediate Species Moricandia Arvensis (L.) Dc. (Mama) and The C₃ Species Brassica Oleracea L. (Cabbage; Cc), Which Differ in Genome Constitution. Moricandia Arvensis Bundle Sheath (Bs) Cells included Many Centripetally Located Chloroplasts and Mitochondria, Whereas Those of Cabbage Had Few Organelles. Hybrid Leaves Were Structurally intermediate Between Those of The Parents and Showed Stronger intermediate C₃―C₄ Features As The Proportion of The Ma Genome increased. The P-Protein of Glycine Decarboxylase (Gdc) Was Confined Mainly To Bs Mitochondria in M. Arvensis, But Accumulated More in The Mesophyll (M) of Cabbage. in The Hybrids, The Accumulation of Gdc in Bs Cells increased With An increasing Ma:C Ratio. Hybrids Exhibited Gradients in Structural and Biochemical Features, Even in Reciprocal Crosses. The Co₂ Compensation Point of Reciprocal Hybrids With High Ma:C Ratios Was Lower Than That of Cabbage But Higher Than That of M. Arvensis. Thus, The Structural and Biochemical Features in Hybrid Leaves Reduced Photorespiration. Moricandia Arvensis Had A Higher Photosynthetic Rate Than Cabbage, But The Photosynthetic Rates of Hybrids Were intermediate Between Those of The Parents Or Comparable To That of M. Arvensis. Our Results Demonstrate That The C₃―C₄ intermediate Characteristics Are inherited Based On The Ratio of The Parent Genomes, and That There Is No Evidence of Cytoplasmic inheritance in These Characteristics.     

Suppression of spinach wilt disease by biological soil disinfestation incorporated with Brassica juncea plants in association with changes in soil bacterial communities

Biological soil disinfestation (BSD) is a method of controlling soil-borne pests and diseases through anaerobic decomposition of plant biomass incorporated in field soil with temporary irrigation and covering with sheets. In this study, effects of BSD on suppression of spinach wilt disease were investigated in two different field experiments using mainly Brassica juncea plants as plant biomass. Soil bacterial community compositions were analyzed with clone library analysis based on 16S rRNA gene sequences to determine the relationship between the bacterial composition in the treated soil and suppression of the disease. For the BSD-treated soils, oxidation–reduction potential dropped, and acetate was usually detected at high concentrations. Although the control treatment (irrigation and polythene covering without biomass) decreased the wilt disease incidence in spinach plants cultivated in the treated plot as compared with those for the non-treated plot, BSD-treatments suppressed the disease more effectively. The clone library results showed that both non-treated and control soils contained diversified bacterial communities of various phylogenetic groups, while members of the Firmicutes mainly from the class Clostridia dominated in the BSD-treated soils. The clostridial groups detected were diverse and the major clone groups were closely related to strictly anaerobic fermentative bacteria such as Clostridium saccharobutylicum, Clostridium cylindrosporum, Clostridium sufflavum, and Clostridium xylanovorans. These clostridial groups were almost eliminated from the soil bacterial community when the BSD-treated soil was treated again with irrigation and covering without biomass before the next cropping, in which the wilt disease was hardly suppressed.     

Sorghum grain yield,forage biomass production and revenue as affected by intercropping time

Sorghum is an excellent alternative to other grains in poor soil where corn does not develop very well, as well as in regions with warm and dry winters. Intercropping sorghum [Sorghum bicolor (L.) Moench] with forage crops, such as palisade grass [Brachiaria brizantha (Hochst. ex A. Rich) Stapf] or guinea grass (Panicum maximum Jacq.), provides large amounts of biomass for use as straw in no-tillage systems or as pasture. However, it is important to determine the appropriate time at which these forage crops have to be sown into sorghum systems to avoid reductions in both sorghum and forage production and to maximize the revenue of the cropping system. This study, conducted for three growing seasons at Botucatu in the State of São Paulo in Brazil, evaluated how nutrient concentration, yield components, sorghum grain yield, revenue, and forage crop dry matter production were affected by the timing of forage intercropping. The experimental design was a randomized complete block design. Intercropping systems were not found to cause reductions in the nutrient concentration in sorghum plants. The number of panicles per unit area of sorghum alone (133,600), intercropped sorghum and palisade grass (133,300) and intercropped sorghum and guinea grass (134,300) corresponded to sorghum grain yields of 5439, 5436 and 5566 kg ha⁻¹, respectively. However, the number of panicles per unit area of intercropped sorghum and palisade grass (144,700) and intercropped sorghum and guinea grass (145,000) with topdressing of fertilizers for the sorghum resulted in the highest sorghum grain yields (6238 and 6127 kg ha⁻¹ for intercropping with palisade grass and guinea grass, respectively). Forage production (8112, 10,972 and 13,193 Mg ha⁻¹ for the first, second and third cuts, respectively) was highest when sorghum and guinea grass were intercropped. The timing of intercropping is an important factor in sorghum grain yield and forage production. Palisade grass or guinea grass must be intercropped with sorghum with topdressing fertilization to achieve the highest sorghum grain yield, but this significantly reduces the forage production. Intercropping sorghum with guinea grass sown simultaneously yielded the highest revenue per ha (€ 1074.4), which was 2.4 times greater than the revenue achieved by sowing sorghum only.     

Effect of N and CO2 supply on source size per grain at anthesis and its relationship with grain growth in wheat

Rising atmospheric CO₂ concentration ([eCO₂]) increases the yield of wheat mainly by increasing grain number, but effects on single grain weight are variable. It is discussed whether single grain growth is limited by the sink or the source size under a non-stress environment. This study explores the effect of e[CO₂] combined with varying N supply on the source and sink size during grain filling. Source size was defined as the amount of stem reserves per grain (SRG) and the proportion of incident radiation intercepted by the green canopy per grain (f_IRG) at anthesis. Data from a 2-year free-air CO₂ enrichment experiment with wheat with three N levels (on average 38 [Nd], 190 [Nad] and 320 kg N ha⁻¹ [Nex]) and two CO₂ levels (393 and 600 ppm) on SRG, f_IRG and grain filling rate (GFR) and duration (GFD) were evaluated. SRG ranged from 2.5 to 12.9 mg and f_IRG from 4.0 × 0.001% to 6.8 x 0.001%. Rising N supply or e[CO₂] decreased SRG and f_IRG via their increases in grain number. Accordingly, there was a negative linear relationship between grain number and SRG (r² ≥ 0.84) or f_IRG (r² ≥ 0.97). Increasing N supply decreased GFR, but increased GFD, and GFR was increased by e[CO₂] under Nad and Nex. For GFR and final grain weight, there was a strong positive (r² ≥ 0.85), and for GFD, a strong negative linear relationship (r² ≥ 0.76) with f_IRG under Nad and Nex. Under these N levels, f_IRG supplied the largest share (>86%) for grain growth and thus single grain growth was possibly source limited under Nad and Nex. Under high grain number such as under Nex and e[CO₂], there might be a risk for low final grain weight due to the low SRG that is insufficient for buffering assimilate shortage under unfavourable environmental conditions in early grain filling.     

Arbuscular mycorrhizal fungal hyphae enhance transport of the allelochemical juglone in the field

Allelopathy is a biological phenomenon where plants have harmful effects on growth of surrounding plants through the production of chemical substances. Here we focus on allelochemical processes which operate belowground, can influence plant interactions and therefore potentially affect plant community structure. Soil hyphae of arbuscular mycorrhizal fungi (AMF) may enhance transport processes in the soil matrix by providing direct connections between plants facilitating infochemical exchange.In a two-component field study we showed that soil hyphae likely play a crucial role in movement of allelochemicals in natural soils and greatly expand bioactive zones by providing effective transport pathways for chemical compounds. First, we tested the effects of Juglans regia leaf litter extract addition in intact or disrupted hyphal networks and simultaneously determined growth reducing effects on sensitive Lycopersicon lycopersicum plants. Second, we analyzed the effect of juglone on tomato by directly adding leaf litter. In both approaches we found an increase of juglone transport if a hyphal network was present, resulting in reduced growth of target plants.Our results, together with previous work, add to the body of evidence for hyphae of soil fungi playing an important role in the transfer of allelochemicals and effectively acting as transport highways in the field. We suggest that hyphal connections, mostly formed by AMF, increase the effectiveness of allelochemicals in natural systems and can play a crucial role in chemical interaction processes in the soil.     

Comparison of paddy soil fertility under conventional rice straw application versus cow dung compost application in mixed crop–livestock systems in a cold temperate region of Japan

ABSTRACT

After the rice harvest in Japan, rice straw (RS) is usually cut by combine harvester and incorporated into the soil to improve its fertility. In mixed crop–livestock systems, however, RS is collected and used as livestock feed, and cow dung compost (CDC) is then applied to the soil. This system utilizes the residual organic matter from both rice production and livestock husbandry to make each product. CDC application is also considered to improve the fertility of paddy soil. However, the nutrient input from CDC and the effect of CDC application on soil fertility vary among regions and/or soil types. We compared soil fertility between RS application (RS treatment, avg. 32 years) and RS removal plus CDC application (CDC treatment, avg. 21 years) in 79 paddy fields in Mamurogawa town, Yamagata Prefecture, a cold temperate region of Japan, and measured the nutrient contents in the applied RS and CDC. The total C content of RS was significantly higher than that of CDC, whereas the N, P, K, and Si contents of CDC were significantly higher than those of RS. However, there was no significant difference in paddy soil fertility – as measured by soil organic C, total N, CEC, available N, P, and Si, exchangeable K, Ca, and Mg, base saturation percentage, pH, and bulk density – between the treatments. The soil fertility of most fields was adequate by RS or CDC treatment. Thus, leaving RS in paddy fields or removing it and then adding CDC to the paddy fields has a similar effect in maintaining adequate soil fertility for single rice production or rice–livestock production systems.