Coupled field formulation of exactly integrated membrane finite elements insensitive to distortion

Abstract

An efficient 4-noded membrane element tolerant and insensitive to mesh distortion is developed using kinematically coupling the in-plane displacements which satisfy the equilibrium equations in Cartesian coordinates and results in material-dependent coupled field interpolation functions making the element free from volumetric and shear locking. The proposed formulation provides a preliminary concept for the satisfaction of natural boundary conditions which is used to satisfy the strong patch test. The proposed element, passed several benchmark problems from the literature, compared well with elasticity solutions, passed the weak patch test and the inf-sup test for both compressible and incompressible cases.     

An extension of ASM2d including pH calculation

This paper presents an extension of the Activated Sludge Model No. 2d (ASM2d) including a chemical model able to calculate the pH value in biological processes. The developed chemical model incorporates the complete set of chemical species affecting the pH value to ASM2d describing non-equilibrium biochemical processes. It considers the system formed by one aqueous phase, in which biochemical processes take place, and one gaseous phase, and is based on the assumptions of instantaneous chemical equilibrium under liquid phase and kinetically governed mass transport between the liquid and gas phase. The ASM2d enlargement comprises the addition of every component affecting the pH value and an ion-balance for the calculation of the pH value and the dissociation species. The significant pH variations observed in a sequencing batch reactor operated for enhanced biological phosphorus removal were used to verify the capability of the extended model for predicting the dynamics of pH jointly with concentrations of acetic acid and phosphate. A pH inhibition function for polyphosphate accumulating bacteria has also been included in the model to simulate the behaviour observed. Experimental data obtained in four different experiments (with different sludge retention time and influent phosphorus concentrations) were accurately reproduced.     

Children’s Parks in Lisbon’s urban spaces: a childhood education and assistance programme during the Portuguese dictatorial regime (1933–1974)

This article deals with how a female member of the elite from the period of the Portuguese dictatorial regime (1933–1974) used Lisbon’s gardens to implement a free childhood education and assistance programme for poor children – the Children’s Parks programme. The Children’s Parks were located in some of Lisbon’s most attractive gardens, housed in pavilions that were directly connected to outdoor spaces. These spaces responded to the educational purposes of the programme, based on the importance of leisure and play activities in outdoor spaces and linked to children’s moral, social, and physical development. In considering the living conditions experienced by children within the context of the Portuguese dictatorship, and by highlighting the way in which these were reflected at the level of architecture and the urban space, the paper seeks to contribute towards an understanding of the place of the child in the history of architecture and urbanism. Besides reflecting the social and educational identity of the project, the urban and architectural settings of the programme were crucial for its success. The interpretation of this case provides a basis for reflecting on the historical and current significance of children’s spaces, and for examining a number of social, educational, architectural, and urban questions.     

实用主义代码70后中国建筑师之建筑数字观

文章指出,70后中国建筑师站在计算机带来的新技术变迁的时代前沿从电脑普及化到电脑计算化,首当其冲受到技术革命带来的设计方法和过程改变的洗礼,从而对数字设计具有敏锐触觉。70后受到的教育延续布扎体系,深悉建筑本质：几何形态、空间、质感,光线和建构。＂建房子＂的迫切需求让70后的数字时代的建筑观具有强烈实用主义的特征,这样的特征给在中国建筑实践和教育中崛起的70后带来了产生新建筑形态语言和思潮可能的机会。     

中、日、欧的被试者对河川景观注视过程的比较研究

在景观认知·评价过程中,如果把眼球运动作为反映大脑所进行的视觉情报处理过程的外部参数,那么眼的运动方式就可能因评价者的生活经验、知识水平甚至价值观和思维方式的不同而产生差异。因此,可以设想被试者的社会文化背景的差异也有可能会从他们对景观的认知方式上得到体现。作为视觉认知中异域文化差异的比较研究之一,运用眼球运动跟踪仪对评价者的景观认知评价过程进行了跟踪测试,并试图通过对认知过程中的注视点分布、注视点数以及注视点的停留时间和注视内容的变化趋势这几个角度的分析比较来探讨社会文化背景的差异如何体现在人类视觉情报信息的收集整理的外部反应中,从而明确在地域特色景观的保留和营造上构成要素的布局方式的意义。     

群体AHP模式下成品油营销指标分析

成品油营销通过判断、适应、改变影响营销结果的因素,利用正确的营销手段,达到营销目的。分析了成品油营销的综合评价指标体系,利用群体AHP模型分析计算各指标权重并进行综合评判,对影响成品油营销的各指标体系进行最终排序,得出其中的关键指标,有利于对营销活动进行整体的控制和改进。     

麦克斯韦方程时域无网格算法及其应用研究

发展了用于求解麦克斯韦方程的时域无网格算法. 该法计算区域直接快速布点构成点云离散;基于点云结构,引入二次极小曲面逼近确定空间导数,构造近似黎曼解处理算法涉及的通量运算;空间离散后的半离散方程则按照四步Runge-Kutta格式推进求解. 基于发展的算法,数值模拟了二维典型目标的电磁散射场,计算结果与文献结果或理论解一致. 还给出了主体带外挂和飞机模型算例,表明该发展的算法适合处理多体及多部件干扰等复杂情形.     

Effects of Rhizosphere Bacteria on Strawberry Plants (Fragaria × ananassa Duch.) under Water Deficit

Due to the observed climate warming, water deficiency in soil is currently one of the most important stressors limiting the size and quality of plant crops. Drought stress causes a number of morphological, physiological, and biochemical changes in plants, limiting their growth, development, and yield. Innovative methods of inducing resistance and protecting plants against stressors include the inoculation of crops with beneficial microorganisms isolated from the rhizosphere of the plant species to which they are to be applied. The aim of the present study was to evaluate 12 different strains of rhizosphere bacteria of the genera Pantoea, Bacillus, Azotobacter, and Pseudomonas by using them to inoculate strawberry plants and assessing their impact on mitigating the negative effects of drought stress. Bacterial populations were assessed by estimates of their size based on bacterial counts in the growth substrate and with bioassays for plant growth-promoting traits. The physiological condition of strawberry plants was determined based on the parameters of chlorophyll fluorescence. The usefulness of the test methods used to assess the influence of plant inoculation with rhizosphere bacteria on the response of plants growing under water deficit was also evaluated. A two-factor experiment was performed in a complete randomization design. The first experimental factor was the inoculation of plant roots with rhizosphere bacteria. The second experimental factor was the different moisture content of the growth substrate. The water potential was maintained at −10 to −15 kPa under control conditions, and at −40 to −45 kPa under the conditions of water deficit in the substrate. The tests on strawberry plants showed that the highest sensitivity to water deficiency, and thus the greatest usefulness for characterizing water stress, was demonstrated by the following indices of chlorophyll “a” fluorescence: F_M, F_V, F_V/F_M, PI, and Area. Based on the assessment of the condition of the photosynthetic apparatus and the analysis of chlorophyll “a” fluorescence indices, including hierarchical cluster analysis, the following strains of rhizosphere bacteria were found to have favorable effects on strawberry plants under water deficit: the Bacillus sp. strains DLGB2 and DKB26 and the Pantoea sp. strains DKB63, DKB70, DKB68, DKB64, and DKB65. In the tests, these strains of Bacillus sp. exhibited a common trait—the ability to produce siderophores, while those of Pantoea sp. were notable for phosphate mobilization and ACCD activity.     

东张西望

在全球化背景下,随着东部的崛起, 边缘化是西部建筑师所面临的共同挑战。西部历史悠久,地域辽阔,民族众多,不同地区建筑师的反应和追求也不同。既有弃西就东的随从,也有不论东西只分良莠的选择,还有向文化中心地努力的企图。在本质上西部建筑学与东部一样,属于全球化语境下的地域建筑学探索。但东张西望是西部建筑师的总体生存状况。     

基于凯恩方程的机器人动力学递推算法

本文在凯恩动力学方程的基础上,提出了一种新的机器人动力学递推算法。这种方法直观简练,可以不经拆链就能较方便地解决带有局部闭链结构的操作手动力学问题,尤其适用于计算机编程计算。本文用这种算法对2自由度4杆机构进行了计算,列出了它的动力学公式。