131 research outputs found
Where and how much : density scenarios for the residential build-out of Gaoming, China
No full textThesis (S.M. and M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 93-95).The author will use Gaoming District in the western part of China's Pearl River Delta (PRD) as an opportunity to examine the impact a range of residential densities along planned public transportation corridors can have on the rate and degree of agricultural land conversion in urbanizing areas. The author will use collected field data on the existing densities of old and new residential building construction in Gaoming, Gaoming District's 2004 Master Plan, projected population and economic growth figures from the Gaoming planning Department, and the parameters of land leasing and revenue generation in China as inputs in her analysis. The author will then present scenarios where a range of residential densities is created from variations in the degree of government planning, public transportation investment and land leasing methods. Moreover, the author will present instructions to build an economic model for planners to understand the land valuation process by which private developers bid for land. Lastly, the author will make recommendations to the planners and officials for how they can generate more revenue from land and work towards the sustainable build-out of Gaoming.by Karen Jia Ying Hu.S.M.and M.C.P
Interception of exotic ants and survey of the ant fauna at Gaoming Port, China
No full textGlobalization of trade and tourism has promoted the dispersal of exotic animals and plants around the world. Quantifying the invasion of exotic insects resulting from overseas trade is essential for national and international risk assessments. Seaports are important hubs for the arrival of exotic insects and a pathway for the invasion of alien species. Analyzing the interception data of exotic species at seaports and investigating the surrounding areas can improve our understanding and limit the risks of biological invasions. In this study, we examined the diversity of ant species associated with different shipping commodities and the origin of exotic ants arriving at Gaoming Port, China, during 2014–2017. In addition, we surveyed the ant communities at the port using bait and pitfall traps. We found 609 records of ants that were intercepted from foreign imports over a four years period, with most originating from Southeast Asian countries. Dolichoderus thoracicus and other species belonging to this genus were the most frequently intercepted species, accounting for 35.79% of interceptions. Solenopsis spp., Anoplolepis gracilipes and several other species presenting significant risks to ecosystems, agriculture, forestry and human health were also intercepted on several occasions. Field surveys showed that Solenopsis invicta was the dominant ant species in the seaport ant community, which also harbored other known tramp species, such as Tapinoma melanocephalum and Paratrechina longicornis. This study indicates that there is high probability of the introduction of foreign ants through seaports. Strengthening quarantine work and monitoring at and near ports is helpful for reducing the risks of the establishment and spread of exotic ants during the early phases of invasion associated with ports. © This article is distributed under a Creative Commons Attribution License CCBY4.
Fu li bian jie, she hui zi ben he Zhongguo liu dong er tong de jiao yu biao xian =: Welfare boundary, social capital, and educational outcomes of migrant children in contemporary China
No full textPh.D.The education of migrant children has been one of the most critical social problems in mainland China. It has been well documented in the literature that social capital has positive effects on the educational outcomes of migrant children. However, these effects could vary among different groups of migrant children. This might have resulted from the fact that little attention has been paid to the impact of institutional factors on the operation of social capital. Therefore, by establishing a conceptual framework of welfare boundary, social capital and educational outcome, the aim of this research is to examine the effects of social capital on educational outcomes, as well as the mechanism that welfare boundary modifies the effects of social capital.Employing the mixed methods, the present study reveals that social capital has significant and positive effects on the educational outcomes of migrant children. The effects, however, are distinctive for different groups of migrant children. In the municipalities where the welfare boundary is relatively more rigid, the social capital effects on children’s education are weaker than that in other provinces. Likewise, in the contexts where the welfare boundary is more restrictive (as reflected by the eligibility of continuing secondary education in the city), the positive effects of social capital are also more reserved. Moreover, it is the mechanism of social insurance eligibility that the moderation of welfare boundary exerts impacts. Findings of this research will not only contribute to the theory advancement in welfare boundary and social capital, but also shed light on social policy reform and social work practice in contemporary China.流動兒童在城市的教育困境是當今中國最重要的社會問題之一。國內外文獻普遍認為社會資本對流動兒童教育表現具有積極的效應，卻也發現不同流動兒童群體的社會資本效應存在差異。本研究認為這種社會資本的雙重效應是因為現有文獻忽視了社會資本效應可能受到結構因素的影響。因此，本研究著力構建了福利邊界、社會資本和教育表現的概念關係，旨在重點探索社會資本對教育表現的影響、福利邊界對社會資本的調節作用以及福利邊界的影響機制。本研究採用混合研究方法，發現總體上家庭和學校層面的社會資本對流動兒童的教育表現呈現積極而顯著的影響。然而，這種社會資本效應會對不同流動兒童群體產生不同的影響：在福利邊界較強的直轄市，流動兒童的社會資本效應明顯低於福利邊界較弱的非直轄市；福利邊界以內的流動兒童的社會資本效應明顯強於福利邊界以外的流動兒童；並且，福利邊界的限制程度越高，流動兒童的社會資本效應就會越低。質化分析結論更進一步揭示了福利邊界如何通過社會保險作為紐帶，將教育限制政策轉變為個體社會資本效應的影響鏈條。這些研究結論不僅填補了現有研究文獻的空白，還將對中國的社會政策和社會工作實踐提供新的啟示和建議。馬高明.Parallel title from added title page.Thesis Ph.D. Chinese University of Hong Kong 2017.Includes bibliographical references (leaves 98-112).Abstracts in English and Chinese.Title from PDF title page (viewed on February 11, 2020).Ma Gaoming
Adsorption of bile salts by multifunctional resins
No full textAmmonium-containing polyacrylamide resins, ammonium-containing polystyrene resins, and their metal-ion coordinated analogs have been synthesized for the sorption of bile salts (BS). The effects of altering the backbone, the type of ammonium group, the number of ammonium group, the hydrophobicity of the pendant group, and of varying the metal ions on the adsorption of BS's, were studied to elucidate the structure-activity relationship.The binding capacity of the resins for BS's generally increased with increasing number of ammonium groups per pendant group of the ammonium-bearing resins, and with higher charge of the metal complex cation of the metal-ion coordinated resin, demonstrating the primary importance of electrostatic interactions. It was also observed that, as the resin backbone was changed from hydrophilic polyacrylamide to hydrophobic polystyrene, the adsorption capacity increased substantially, demonstrating that hydrophobic interactions (H-H's) between the resin backbone and the BS's also play a significant role in the binding. The incorporation of hydrophobic segments -(CH- into the pendant groups on polyacrylamide resins increased binding capacity, but had no effect for the more hydrophobic polystyrene resins. Primary ammonium-bearing resins often showed higher binding capacities than their quarternary analogs, suggesting that H-bonding reinforces the binding. Isotherms with an S-shape observed for most polyacrylamide resins indicate a positive cooperativity in the binding due to H-H's and H-bonding among BS anions bound at adjacent positions within resin beads. Binding models have been proposed to depict the formation of pendant group-BS mixed reversed micelles and ordinary BS micelles.The studies of the kinetics of the binding of BS anions by the resins showed that a small resin particle size and more intense shaking substantially increase the rate of binding. This indicates that the binding process is mainly controlled by the diffusion of BS anions near and within the beads. (Abstract shortened by UMI.
Damage evolution in nanoclay-reinforced polymers: A three-dimensional computational study
No full textInitiation and growth of microcracks in the nanoclay reinforced polymer composites were analyzed in numerical experiments using 3D micromechanical unit cell models. An original program code for the automatic generation of FE unit cells with multiple disk-shaped nanoplatelets, with high aspect ratio, clustered or exfoliated, randomly arranged or inclined, was developed. A four phase model of nanocomposites which includes the effective interface between the nanoplatelets and polymer, as well as interplatelet and outer phases, was used in the simulations. Different crack growth criteria were compared, including the 3D Benzeggagh and Kenane law (BK law) criterion, the 3D Wu and Reuter law (power law) criterion and the Reeder law criterion. The effects of the platelelet aspect ratio, clustering and orientation effects on the crack propagation are studied in numerical experiments. It was observed that the increasing aspect ratio leads to the increasing Young modulus, but decreasing strength. The clustering of disks had an adverse effect, meaning increased strength and lower stiffness. In the simulations, damage mechanisms such as crack deflection and delamination were observed
Patrus wui
No full text<i>Patrus wui</i> (Ochs, 1932) <p> <i>Orectochilus wui</i> Ochs, 1932: 57 (original description).</p> <p> <i>Orectochilus</i> (<i>Patrus</i>) <i>wui</i> – Mazzoldi 1995: 165 (catalogue).</p> <p> <i>Patrus wui</i> – Hájek & Fery 2017: 29 (catalogue).</p> Material examined <p> CHINA – <b>Guangdong •</b> 15 ex.; 广东肇庆黑石顶 [Guangdong, Zhaoqing, Heishiding]; 25 Jul. 2018; 贾凤龙采 [Jia Fenglong leg.]; SYSU • 4 ex.; 广东封开县黑石顶 [Guangdong, Fengkai, Heishiding]; 23°31′ N, 111°52′ E; 20–22 Sep. 2014; 贾凤龙, 唐余丹采 [Jia Fenglong, Tang Yudan leg.]; SYSU • 7 ex.; 广东省封开县黑石顶 [Guangdong, Fengkai, Heishiding]; 23°31′ N, 111°52′ E; 20–22 Sep. 2014; 贾 凤龙, 林仁超, 唐余丹采 [Jia Fenglong, Lin Renchao, Tang Yudan leg.]; SYSU • 2 ex.; 广东封开黑石 顶 [Guangdong, Fengkai, Heishiding]; 11 Jul. 2000; 罗菁采 [Luo Jing leg.]; SYSU • 2 ♂♂; 广东封 开黑石顶 [Guangdong, Fengkai, Heishiding]; 5 Jul. 1987; 钟声雄采 [Zhong Shengxiong leg.]; SYSU • 1 ♂; 广东封开黑石顶 [Guangdong, Fengkai, Heishiding]; 3 Jul. 1987; 陈邵峰采 [Chen Shaofeng leg.]; SYSU • 1 ♂, 2 ♀♀; 广东鼎湖山 [Guangdong, Dinghushan Mt.]; 22 Jul. 1964; 吴思添采 [Wu Sitian leg.]; SYSU • 1 ♂; 广州河南 [Guangzhou, Henan]; 15 Oct. 1992; 邝骉采 [Kuang Biao leg.]; SYSU • 1 ♀; 广东乳源南岭半山腰保护站 [Guangdong, Ruyuan, Nanling Hillside Reserve Station]; alt. 1000 m; 23 Aug. 2010; 赵爽采 [Zhao Shuang leg.]; SYSU • 1 ♀; 广东高明杨梅镇 [Guangdong, Gaoming, Yangmei Town]; May 2004; 采集人: 贾凤龙 [Jia Fenglong leg.]; SYSU • 2 ♂♂, 2 ♀♀; 广东 高明杨梅镇 [Guangdong, Gaoming, Yangmei Town]; 23–26 Apr. 2006; 采集人: 贾凤龙 [Jia Fenglong leg.]; SYSU • 1 ♂, 1 ♀; 广东高明杨梅镇 [Guangdong, Gaoming, Yangmei Town]; 20–27 Apr. 2006; 袁采亚采 [Yuan Caiya leg.]; SYSU • 1 ♂; 广东高明杨梅镇 [Guangdong, Gaoming, Yangmei Town]; 20–27 Apr. 2006; 胡剑采 [Hu Jian leg.]; SYSU.</p> Distribution <p>Endemic to south China. Known from Fujian. New for Guangdong.</p>Published as part of <i>Liang, Zulong, Angus, Robert B. & Jia, Fenglong, 2021, Three new species of Patrus Aubé with additional records of Gyrinidae from China (Coleoptera, Gyrinidae), pp. 1-39 in European Journal of Taxonomy 767</i> on page 32, DOI: 10.5852/ejt.2021.767.1481, <a href="http://zenodo.org/record/5715526">http://zenodo.org/record/5715526</a>
Experimental and numerical investigation on precast CECFST column-to-column connections subjected to axial and eccentric compression
No full textConcrete-encased concrete-filled steel tube (CECFST) is a new type of composite member featuring superior structural performance and high construction productivity. This form of structural members has been increasingly used as columns in high-rise buildings and as piers in long-span bridges. Recently, to promote the application of CECFST columns in countries short of labour, e.g., Singapore, North America and Europe, an advanced precast CECFST column-to-column connection with rapid construction and excellent tensile performance was developed by the authors. However, behaviour of the developed precast connection subjected to axial and eccentric compression has not been studied so far. In this paper, an experimental programme including five connection tests was conducted to investigate compression performance of the developed precast connection. The test results showed that compression resistance of the precast connection could achieve that of CECFST columns, indicating that it is feasible to connect CECFST columns by the newly proposed precast connection to enhance construction productivity. Furthermore, an extensive finite element (FE) modelling programme was carried out to generate more numerical data by conducting parametric studies. The experimental and numerical results showed that connection configuration plays a pivotal role in load-carrying capacity of the precast connection. Based on EN 1994-1-1, one simplified strength prediction model was proposed for the proposed precast CECFST column-to-column connection. Compared with experimental and numerical results, the predicted strength was conservative and consistent, indicating that the proposed approach can be used in the design of the precast connection.The project entitled “The behaviour and design of innovative composite concrete-steel structural system” ((RCA-17/114) funded by Jurong Town Corporation (JTC) in Singapore is gratefully acknowledged by the author
Restoration and management of the Inner Mongolia Grassland requires a sustainable strategy
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