Experimental Study on Bubble Pulse Features Under the Combined Action of Horizontal and Vertical Walls

The pulse features of a bubble have a close connection with the boundary condition. When a bubble moves near a rigid wall, it will be attracted by the Bjerknes force of the wall, and a jet pointing at the wall will be generated. In real application, the bubble may move under the combined action of walls in different directions when it forms at the corner of a pipe or at the bottom of a dam. The motion of the bubble shows complex and nonlinear characteristics under these conditions. In order to investigate the bubble pulse features near complex walls, a horizontal wall and a vertical wall are put into the experimental water tank synchronously, and an electric circuit with 200 voltages is designed to generate discharge bubbles, and then experimental study on the bubble pulse features under the combined action of horizontal and vertical walls is carried out. The influences of the combined action of two walls on the bubble shape, pulse period, moving trace and inside jet are obtained by changing the distances from bubble center to the two walls. It aims at providing references for the relevant theoretical and numerical research.

Study on scour around vertical large-size cylinder base due to combined action of wave and current

Based on the mechanism of local scour around vertical large-sized cylinder due to combined action of wave and current,the sour morphology,scour process and the maximum scour depth around the cylinders are studied experimentally.The influence of various ocean environmental parameters on local scour around the cylinder is considered in physical model test.The experimental results indicate that the principal effect factors on the scour in fine-sand seabed are wave height,wavelength,current velocity,ratio of diameter to wavelength and ratio of depth to wavelength when the ratio of cylinder diameter to wavelength is from 0.2 to 0.8.In this paper,dimensional analysis theory is utilized to establish a theoretical equation for forecasting maximum scour depth around large-sized round cylinder base due to the combined action of wave and current.The results computed with the theoretical equation are compared with the experimental results,and found to be in good consistency.The results in this studies can be used to estimate the maximum sour depth around analogous structures.

Multiscale Combined Action and Disturbance Characteristics of Pre-summer Extreme Precipitation Events over South China

The dominant frequency modes of pre-summer extreme precipitation events(EPEs)over South China(SC)between1998 and 2018 were investigated.The 67 identified EPEs were all characterized by the 3-8-d(synoptic)frequency band.However,multiscale combined modes of the synoptic and three low-frequency bands[10-20-d(quasi-biweekly,QBW);15-40-d(quasi-monthly,QM);and 20-60-d(intraseasonal)]accounted for the majority(63%)of the EPEs,and the precipitation intensity on the peak wet day was larger than that of the single synoptic mode.It was found that EPEs form within strong southwesterly anomalous flows characterized by either lower-level cyclonic circulation over SC or a deep trough over eastern China.Bandpass-filtered disturbances revealed the direct precipitating systems and their life cycles.Synoptic-scale disturbances are dominated by mid-high latitude troughs,and the cyclonic anomalies originate from downstream of the Tibetan Plateau(TP).Given the warm and moist climate state,synoptic-scale northeasterly flows can even induce EPEs.At the QBW and QM scales,the disturbances originate from the tropical Pacific,downstream of the TP,or mid-high latitudes(QBW only).Each is characterized by cyclonic-anticyclonic wave trains and intense southwesterly flows between them within a region of large horizontal pressure gradient.The intraseasonal disturbances are confined to tropical regions and influence SC by marginal southwesterly flows.It is concluded that low-frequency disturbances provide favorable background conditions for EPEs over SC and synoptic-scale disturbances ultimately induce EPEs on the peak wet days.Both should be simultaneously considered for EPE predictions over SC.

IN SITU OBSERVATION OF DEFORMATION AND FRACTURE FOR SUPERALLOY GH169 UNDER COMBINED FATIGUE-CREEP ACTION

In Situ observation of deformation and fracture for superalloy GH169 under combined fatigue-creep action is made by using high temperature metalloscope,it is shown that under the test conditions the deformution takes place by merely of slipping,twinning and grain houndary sliding,and the mode of failure depends on the microstructure of specimen. lntergranular cracks arise.from W-type voids produced by the stress concentration at triple point which could not be relaxed by the interior deformation of grains and the local deformathm region along grain bounaries.And the crack propagation mechanism is the nucleation,growth and linkage of carities at the grain boundaries.Transgranular cracks form from deformatiom damages within the grain,and its propagation mechanism is shear rupture along the slip phme.

Chemospecific and Regioselective Ethereal Methyl-Oxygen Bond Cleavage Behavior of Aroylated Dimethoxynaphthalenes by Combined Action of AlCl₃and Aroyl Group

AlCl3-mediated cleavage of ethereal methyl–oxygen bond in aroylated 2,7-dimethoxynaphthalene compounds proceeds chemospecifically and regioselectively. The ethereal bond at the β(2)-position of 1-monoaroylated 2,7-dimethoxynaphthalene is cleaved readily and predominantly against the β(7)-position, whereas scission of β-ethereal bonds of 1,8-diaroylated 2,7-dimethoxynaphthalene hardly undergoes like the non-aroylated mother frame compound of 2,7-dimethoxynaphthalene.

LARGE DEFLECTION PROBLEM OF CIRCULAR PLATES WITH VARIABLE THICKNESS UNDER THE ACTION OF COMBINED LOADS

By using the modified iteration method of large deflection theory of plates with variable thichness[1], we solve the problem of circular plates with variable thickness subjected to combined loads under the boundary conditions of the clamped edges and get comparatively more accurate second-order approximate analytical solution. If the results of this paper are degraded into the special cases, the results coinciding with those of papers [1,2] can be obtained. In this paper, the characteristic curves are plotted and some comparisons are made. The results of this paper are satisfactory.

Heterosis, Combining Ability and Gene Action for Yield in Bottle Gourd

The experiment was conducted at the experimental field of Olericulture Division, Horticulture Research Centre (HRC), Bangladesh Agricultural Research Institute (BARI), Gazipur, Bangladesh during the winter season of 2018-2019 to study the genetic architecture of yield in a seven parent half diallel cross of bottle gourd. The values of mean square for GCA (general combining ability) and SCA (specific combining ability) were highly significant which suggested the presence of both additive and non-additive genetic variance in the population. But the higher magnitude of GCA compared to SCA indicated predominance of additive genetic variance. In most of the cases, the cross between poor and poor parents showed positive SCA effect for fruit yield, which indicated the higher yield. The estimates of significant positive better parent heterosis ranged from 6.27 to 49.72 percent. Analysis of genetic components of variation suggested that additive components were more important in the inheritance of fruit yield. This character was observed being controlled by two to three pairs of genes or groups of genes. Narrow sense heritability was 23 percent indicating probability of selection in generations. The graphical analysis also indicated wide genetic diversity among the parents.

Test on mechanical behavior of SRC L-shaped columns under combined torsion and bending moment

Investigations of the seismic behavior of steel reinforced concrete L-shaped columns under constant axial compression and cycled bending-shear-torsion load were performed.Six specimens,which considered two parameters,i.e.,the moment ratio of torsion to bending(γ)and the aspect ratio(column length-to-depth ratio,φ),were prepared for the experiment.In this study,the failure process,torsion-displacement hysteresis curves,and flexure-displacement hysteresis curves were obtained.The failure characteristics,mechanical behavior of specimens such as the failure patterns,hysteresis curves,rigidity degradation,ductility and energy dissipation,are analyzed.The experimental research indicated that the major failures of the specimens were bending failure,bending-shear failure and bending-torsion failure as the moment ratio of torsion to bending(γ)increased.The torsion-displacement hysteresis curves were pinched in the middle,formed a slip platform,and the phenomenon of“load drop”occurred after the peak load.The bending-displacement hysteresis curves were plump,which showed that bending capacity of the specimen was better than its torsion capacity.Additionally,the energy dissipation of the specimen was dominated by torsion in the early stage and ultimately governed by the bending moment in the later phase.Test results also indicated that the displacement ductility coefficient and interstory rotation angle of the failure point were less than 3.0 and 1/50,respectively,which means the test specimen performance does not meet the requirement of the Chinese Code for Seismic Design of Buildings(GB 50011-2014)in this respect.

Combining ability and gene action studies for yield and fibre traits in Gossypium arboreum using Griffings numerical and Haymans graphical approach

Background For the purpose of utilising hybrid vigour to produce possible hybrids with a suitable level of stability,the knowledge of gene activity and combining ability is a crucial prerequisite before choosing desirable parents.The present study was carried out with six parents crossed in full diallel fashion and generated 30 F1 hybrids.These hybrids were evaluated in two replications in Randomized Block Design at Department of Cotton,TNAU for combining ability and gene action.Diallel analysis was carried out according to Griffing’s method-I(parents + F_(1) + reciprocals) and model-I and Hayman’s graphical approach by using INDOSTAT software.Results Analysis of variance for combining ability indicated that mean square values of GCA,SCA and reciprocals were highly significant for all the traits except for the uniformity index.RG763 and K12 showed highly positively significant GCA effects for most of the yield traits while PA838 and K12 for fibre quality traits,so they were found as best general combiners.PAIG379 × K12 and PDB29 × K12 for yield traits,and PDB29 × PA838,RG763 × PA838,and CNA1007 × RG763 cross combinations for fibre quality traits could be recommended for future breeding programms.Conclusion The results of both Griffing’s and Hayman’s approaches showed that non-additive gene action predominates as SCA variance was bigger than GCA variance,so heterosis breeding is thought to be a more fruitful option for enhancing GCA of many traits.

Combining ability studies in desi cotton(Gossypium arboreum L.)genotypes

Background Studies on genetic variation and combining ability are essential tools to employ the suitable breeding programme,particularly for hybrid production,to exploit the heterosis in cross-pollinated crops like cotton.Thus,combining ability studies in desi cotton(Gossypium arboreum L.)was carried out using 13 diverse parents through diallel mating design,evaluating 78 F,hybrids along with their parents,without reciprocals using Griffing's and Hayman's approaches.Results Genotypes H 509,AC 3265,AKH 496,and PBN 565 exhibited superior per se performance,indicating their potential use as parents in future breeding programs to develop superior hybrids.The general combining ability(GCA)effect of the genotypes revealed that AC 3097 and AKA 13-SP1 were good general combiners for most traits in this study.Genotypes PBS 1127-SP1,AKH 496,H 509,N11-54-31-32,and AKA 13-SP1 exhibited strong combining ability,contributing to a significant specific combining ability(SCA)effect in seven selected crosses(AC 3265×PBS1127-SP1,AKH 496×H 509,AKH 496×AC 3097,PBS 1127-SP1×N11-54-31-32,AC 3216×AKA 13-SP1,H 503×N11-54-31-32,and H 509×AKA 13-SP1)for yield improvement.These crosses showed positive heterosis in a positive direction.Conclusion From the present study,five genotypes(AC 3097,AKA 13-SP1,N11-54-31-32,AC 3265,and H 509)were identified as good general combiners for producing hybrids,and seven combinations showed a promising hybrid for future breeding programs.

Reagent types and action mechanisms in ilmenite flotation:A review

Ilmenite is an essential mineral for the extraction of titanium.Conventional physical separation methods have difficulty recovering fine ilmenite,and dressing plants have begun applying flotation to recover ilmenite.The interaction of reagent groups with Ti and Fe sites on the ilmenite surface dramatically influences the ilmenite flotation.However,the investigation on Fe sites has received more attention because the activity of Ti is lower than that of Fe.For the activators on ilmenite flotation,most are metal ions but typically lead ions.The metal ions of activators promote ilmenite flotation by increasing the active sites on the ilmenite surface.Combined reagents have a better selective separation of ilmenite than single reagents due to their synergistic effect.Combining the lead ion(Pb^(2+))and the benzyl hydroxamic acid(BHA)into a Pb-BHA complex has a marked effect on ilmenite flotation,which puts forward a new idea of developing combined reagents for ilmenite flotation.This review considers reagent types and action mechanisms in ilmenite flotation.On the basis of the analysis of previous research,a brief future outlook of reagent types and action mechanisms in ilmenite flotation is also proposed in this study.

Nature of Gene Action and Maternal Effects for Pod Borer, <i>Helicoverpa armigera</i>Resistance and Grain Yield in Chickpea, <i>Cicer arietinum</i>

Information on mechanisms and inheritance of resistance is critical to plan an effective strategy to breed for resistance to insect pests. Therefore, we evaluated a diverse array of chickpea genotypes (eight desi and one kabuli) with varying levels of resistance to the pod borer, Helicoverpa armigera to gain an understanding of the nature of gene action and possible maternal effects. The test genotypes were crossed in all possible combinations for a full diallel. The 72 F1s (36 direct and 36 reciprocal crosses) along with the parents were evaluated for resistance to H. armigera under field conditions, and for antibiosis mechanism of resistance (larval survival and larval weight gain) by using detached leaf assay under laboratory conditions, and grain yield under un-protected conditions in the field. Additive gene action governed the inheritance of resistance to H. armigera, while non-additive type of gene action was predominant for inheritance of antibiosis component of resistance (larval survival and larval weight) and grain yield. Greater magnitude of σ2 A(17.39 and 1.42) than σ2 D (3.93 and 1.21) indicated the preponderance of σ2 Ain inheritance of resistance to pod borer, H. armigera under laboratory and field conditions, respectively. There were no maternal effects for inheritance of resistance to pod borer and grain yield. Lines with significant gca effects for pod borer damage and grain yield were identified for further use in the resistance breeding program. The implications of the inheritance pattern of pod borer resistance and grain yield are discussed in the context of strategies to enhance pod borer resistance and grain yield in chickpea.

Dynamic simulation of hydrodynamic model of drum level wave action and sloshing

In order to build the model of the drum level wave action and sloshing, based on the method of modularization modeling, the hydrodynamic model of drum level wave action and sloshing was developed, and dynamic simulation researches were carried out based on the model. The results indicate that both drum level and drum length have functional relations with period of drum level wave action and sloshing. When the drum level decreases or drum length increases, the period of drum level wave action and sloshing increases, density of liquid and number of sub-module division have little influence on the period of drum level wave action and sloshing. The model was validated by the analytical solution theory of liquid’s wave action and sloshing in cuboid container, and the 3D graphics of drum level wave action and sloshing was also obtained. The model can dynamically reflect the rules of wave action and sloshing of water in the container exactly.

Theory of pleiotropic action of biologically active compounds and medicines—Basic principles and practical application

This article represents the main positions of the theory of pleiotropic action of biologically active compounds (BACs) and medicines, which has been designed by the author based on her own experimental researches. The term “pleiotropy” means the ability of the BACs and medicines to implement more than one mechanism of action resulting in the specific biological (pharmacological) effect. The interaction of these mechanisms forms a distinct pattern of biological response (pleiotropic pattern), which reflects the change in his character with the increased dose (concentration)-dependent efficacy of BACs and medicines. The article consists of description of different pleiotropic patterns established in experiments on the model of reactive oxygen species (ROS) generation by macrophages dependent on activity of specialized enzyme called Nox2-NAD(P)H oxidase (Nox2, EC 1.6.3.1). Moreover, it consists of explanation of pharmacodynamic nature of pleiotropic patterns by means of application Chou-Talalay median effect equalization and combination index (CI) theory. The novel theory explains unsolved until now universal aspects of activity BACs and medicines, such as slope angles of “dose-effect” dependences in the conditions relevant in vivo, and it is of fundamental interest. However, it has applications in experimental pharmacology, as it allows defining the choice of the individual compounds and combinations, modulating the trust effect selectively and efficiently. This knowledge opens up new approaches to medicines discovery and evaluation, their rational dosing and combining.

地震和风耦合作用下超高层连体结构易损性分析

为探究超高层连体结构在多灾害耦合作用下的设计与安全性能,以苏州超塔为例,开展地震和风耦合作用下的多灾害易损性分析.根据设计资料建立结构有限元模型,分别开展结构在地震作用下以及地震和风耦合作用下的易损性分析,探究结构在多灾害耦合作用下的响应规律.结果表明,地震和风耦合作用下结构联合易损性随着地震动和风荷载强度的增大而增加,且地震动对结构的破坏占主导作用.地震与风耦合作用时结构达到中等破坏、严重破坏和倒塌破坏的概率均比仅地震作用时有所增加.当风速达到40 m/s时,结构在罕遇地震下达到3种破坏状态的概率分别为99.77%、91.56%和46.54%,相比于仅罕遇地震作用下分别提高了1.11%、10.73%和14.65%,相比于一般高层连体结构在同样的灾害耦合作用下分别提高了0.27%、6.26%和14.34%.

模块化建筑刚性桩复合地基共同作用试验分析

本文依据某模块化示范楼,制作了简化后的1∶10的模块化建筑刚性桩复合地基的室外缩尺模型,考虑了上部模块结构与地基基础共同作用。通过模型试验分析了上部模块刚度变化对上部模块钢柱、筏板基础和刚性桩复合地基各受力体的影响。结果表明:模块化建筑中部柱轴力>边部柱轴力>角部柱轴力;随上部模块刚度的增加,中部柱轴力逐渐减小,边部柱和角部柱轴力逐渐增大;筏板基础中部沉降最大,边部沉降最小,整体沉降随上部模块楼层的增加逐渐增大;角部桩身轴力>边部桩身轴力>中部桩身轴力,桩身轴力沿着桩深度方向先增大后减小;桩身上部一定范围内产生负摩阻力。分析结果能够为模块化建筑单元构件设计及刚性桩复合地基基础优化设计提供参考。

地震-波浪联合作用下考虑冲刷效应的跨海斜拉桥振动台试验研究

针对跨海桥梁服役期内可能遭受地震、波浪以及冲刷效应影响的问题,开展地震与波浪联合作用下考虑冲刷效应的跨海斜拉桥振动台试验,研究地震与波浪联合作用下冲刷效应对斜拉桥动力特性及关键截面动力响应(加速度、位移和应变)的影响规律。研究表明:随着冲刷深度的增加,斜拉桥自振频率逐渐降低;冲刷深度的增加,降低了桥塔桩基础侧向约束,引起地震与波浪联合作用下桩顶动力响应明显增大,且增幅比其他位置更为显著;边墩墩顶加速度和相对位移均大于辅助墩墩顶,桥墩抗震设计时,应采用不同配筋率和不同的截面尺寸对边墩和辅助墩开展差异化设计;考虑冲刷效应明显增大了地震与波浪联合作用下塔底、边墩和辅助墩墩底等关键截面的应变,相较于无冲刷工况,大冲刷工况下塔底、边墩及辅助墩墩底应变分别增加39%、36%和42%,抗震设计时应高度重视。

索-悬链线拱联合结构的受力机理与力学特征

早期拱桥已运营多年,缺乏有效的养护,且设计荷载等级偏低;随着交通量的增加及车辆超载,其在活载作用下的力学性能已不能满足现代交通需求。为改善此类拱桥的受力性能,提出一种索-悬链线拱联合结构,在拱肋两侧对称设置索,使索和拱肋形成新的受力体系,从而改变悬链线拱结构的传力路径,进而降低拱结构的内力。在索-拱联合结构图式下,基于弹性中心法对其力法方程进行简化,采用近似曲线积分方法推导了竖向移动荷载作用下拱肋的内力解析解,并借助ANSYS有限元软件验证解析解的准确性;分析了在车道荷载作用下索约束位置、拱轴系数、矢跨比和轴向刚度比等设计参数对拱结构的影响,揭示了索-拱联合结构的受力机理和内力变化规律。研究表明,内力解析解与有限元结果的相对误差在1%以内;索的设置改变了拱结构弯矩影响线量值的正、负区间分布,而且有效地降低了拱结构弯矩影响线的峰值,从而使拱结构的整体弯矩得到较大幅度的降低,弯矩分布更均匀;沿拱脚至拱顶,拱结构弯矩的降低幅度和轴力的增长幅度均逐渐减小;轴向刚度比从0.02增加至0.10,拱脚负弯矩的减小幅度呈非线性增大,最大降幅达63.7%;索力的增长幅度与其数值大小成反比,当索设置在距拱顶0.3L(L为拱跨经)时,索力可增至轴向刚度比为0.02时的1.9倍。矢跨比对拱结构内力带来的影响不容忽视,矢跨比越大拱结构的内力变化幅度越大;拱轴系数对拱结构内力的影响可以忽略。

风-浪联合作用下斜拉-悬索协作体系桥车-桥耦合振动仿真研究

为保证海洋环境下斜拉-悬索协作体系桥列车运行的安全性和舒适度,对该类桥梁进行风-浪联合作用下的车-桥耦合振动仿真研究。以某公铁两用斜拉-悬索协作体系桥为背景,采用ANSYS软件建立桥梁有限元模型,采用多体系统动力学软件SIMPACK建立列车动力学模型,利用重叠网格技术,模拟车-桥耦合系统在不同风速和车速下的气动荷载,采用FLOW-3D软件计算桥梁下部复合基础的规则波浪荷载,建立风-浪联合作用下的车-桥耦合振动模型,分析波高、风速和车速对车-桥耦合系统动力响应的影响规律。结果表明:在风-浪-车-桥耦合系统中,列车各动力学指标均随波高增大而增大,桥梁跨中横向位移随波高增大而显著增大,而跨中竖向位移几乎不受影响;列车各动力学指标均随风速提高而显著增大,桥梁跨中竖向位移随风速提高而减小;列车各动力学指标均随车速增大而增大,桥梁跨中横向位移和横向加速度不随车速改变而显著变化,桥梁竖向位移和竖向加速度随车速提高而显著增大。

考虑桩-土相互作用的超大型单桩式海上风机结构地震响应

为了解决桩-土相互作用对超大型单桩式海上风机结构地震响应影响的问题,基于IEA 15 MW的固定式单桩海上风机原型,使用Abaqus建立考虑桩-土相互作用与泥面固定2种风机结构模型,桩-土相互作用通过一组非线性弹簧模拟。考虑风-波浪与地震联合作用,分析桩-土相互作用对超大型固定式单桩海上风机结构动力响应的影响。结果表明:针对超大型海上风机,桩-土相互作用效应使风机支撑结构的特征频率降低3%~6%;考虑桩-土相互作用的大兆瓦风机动力响应远大于泥面固定风机模型的动力响应;海上风机尺寸越大,桩-土相互作用引起的海上风机结构动力响应偏差越显著。