Numerical simul tion of droplet impact erosion : dang van fatigue approach

The aim of this work is to understand the erosion mechanism caused by repeated water droplets impingement on a metallic structure, and then perform numerical simulations of the damage. When a high velocity water droplet with small diameter impacts a rigid surface, interaction is driven by inertial effects. Upon impact, the “water-hammer” pressure appears by inertial effect at the center of the contact though the maximum pressure occurs on the envelope of the contact area. Lateral jetting occurs by compression when the wave front travelling inside droplet overtakes the contact area. Concerning the structure, erosion is due to fatigue crack- ing. First, material grains are weakened during an “incubation” phase. After a large number of impacts, micro-cracks emerge and lead to ejection or fracture of grains, what is called “am- plification” phase. Numerical simulation including rigid solid allows to locate the most loaded zones of the area, by observing the pressure and mainly the impulse. A 2-way coupling compu- tation with fluid-structure interaction at macroscopic scale allows to confirm the fatigue-based mechanism by observing the hydrostatic stress. Finally, erosion program developed with Dang Van criterion provides the location of the most eroded zones of the structure during a loading cycle. They locate at the edge of jetting zone, which shows the influence of microjets in the erosion mechanism

Law, Social Norms and Welfare as Means of Public Administration: Case Study of Mahalla Institutions in Uzbekistan

Despite numerous challenges, since its independence, Uzbekistan, with the exception of the May 2005 Andijan events, has enjoyed extraordinary political stability and not recorded any considerable cases of interethnic or interfaith conflict, regime change or civil war, whereas neighboring Kyrgyzstan, labeled an “island of democracy” by the Western world, has experienced numerous conflicts and chaos, ranging from “color revolutions” to ethnic conflict. However, for understanding Uzbekistan’s ability to cope with internal and external challenges, little recourse is made to the post-independence discourse on public administration known as “mahalla reforms”. In spite of the significant existing body of literature on the mahalla, there has been little systematic scholarly investigation of the role of mahalla in maintaining political stability and security in Uzbekistan. Previous studies did not provide an account of how the law, social norms and welfare come to interplay in the mahalla system and how this influences the public administration developments in Uzbekistan. This paper begins to redress this lacuna by analyzing public-administration reforms in post-independence Uzbekistan, namely mahalla reforms, with an effort to show how political and social stability is established through mahalla, and to what extent those reforms have affected the position of individuals vis-à-vis the public-administration system. In undertaking this task, the paper employs three theoretical concepts: the theory of norms, the welfare-pentagon model and the theory of social control. In this paper, I argue that public-administration reforms since 1991 have transformed mahalla into a comprehensive system of social control; and therefore, mahalla can be places of democratic involvement or sites of authoritarianism in Uzbekistan

The impact of educational attainment on household poverty in South Africa: A case study of Limpopo province

Poverty is a phenomenon that is multidimensional in nature and its meaning varies from one individual to another (Alkire and Foster 2011; Batana 2013; Bossert, Chakravarty, and D'Ambrosio 2013; Jansen et al. 2015). It can be seen as a failure to attain certain capabilities, absolute or relative,2 or a lack of income to meet a certain standard of living in a given society (Jansen et al. 2015). It can be chronic or temporary3, is often linked with underdevelopment, economic exclusion and vulnerabilities, and sometimes closely correlated with inequality (Mbuli 2008; Van der Berg 2008; Jansen et al. 2015). The definition of poverty employed determines its measurement

Poverty and 'Second Economy' in South Africa: An Attempt to Clarify Applicable Concepts and Quantify Extent of Relevant Challenges

In brief, the paper firstly summarises old and new theoretical and technical issues on measuring poverty, secondly analyses poverty from different perspectives and highlights various research findings on poverty trends in South Africa and thirdly clarifies the notion of "second economy" and attempts to "measure" it

Using a community-based definition of poverty for targeting poor households for premium subsidies in the context of a community health insurance in Burkina Faso

Background: One of the biggest challenges in subsidizing premiums of poor households for community health insurance is the identification and selection of these households. Generally, poverty assessments in developing countries are based on monetary terms. The household is regarded as poor if its income or consumption is lower than a predefined poverty cut-off. These measures fail to recognize the multi-dimensional character of poverty, ignoring community members? perception and understanding of poverty, leaving them voiceless and powerless in the identification process. Realizing this, the steering committee of Nouna's health insurance devised a method to involve community members to better define `perceived? poverty, using this as a key element for the poor selection. The community-identified poor were then used to effectively target premium subsidies for the insurance scheme. Methods: The study was conducted in the Nouna's Health District located in northwest Burkina Faso. Participants in each village were selected to take part in focus-group discussions (FGD) organized in 41 villages and 7 sectors of Nouna's town to discuss criteria and perceptions of poverty. The discussions were audio recorded, transcribed and analyzed in French using the software NVivo 9. Results: From the FGD on poverty and the subjective definitions and perceptions of the community members, we found that poverty was mainly seen as scarcity of basic needs, vulnerability, deprivation of capacities, powerlessness, voicelessness, indecent living conditions, and absence of social capital and community networks for support in times of need. Criteria and poverty groups as described by community members can be used to identify poor who can then be targeted for subsidies. Conclusion: Policies targeting the poorest require the establishment of effective selection strategies. These policies are well-conditioned by proper identification of the poor people. Community perceptions and criteria of poverty are grounded in reality, to better appreciate the issue. It is crucial to take these perceptions into account in undertaking community development actions which target the poor. For most community-based health insurance schemes with limited financial resources, using a community-based definition of poverty in the targeting of the poorest might be a less costly alternative

Numerical simul tion of droplet impact erosion : dang van fatigue approach

The aim of this work is to understand the erosion mechanism caused by repeated water droplets impingement on a metallic structure, and then perform numerical simulations of the damage. When a high velocity water droplet with small diameter impacts a rigid surface, interaction is driven by inertial effects. Upon impact, the “water-hammer” pressure appears by inertial effect at the center of the contact though the maximum pressure occurs on the envelope of the contact area. Lateral jetting occurs by compression when the wave front travelling inside droplet overtakes the contact area. Concerning the structure, erosion is due to fatigue crack- ing. First, material grains are weakened during an “incubation” phase. After a large number of impacts, micro-cracks emerge and lead to ejection or fracture of grains, what is called “am- plification” phase. Numerical simulation including rigid solid allows to locate the most loaded zones of the area, by observing the pressure and mainly the impulse. A 2-way coupling compu- tation with fluid-structure interaction at macroscopic scale allows to confirm the fatigue-based mechanism by observing the hydrostatic stress. Finally, erosion program developed with Dang Van criterion provides the location of the most eroded zones of the structure during a loading cycle. They locate at the edge of jetting zone, which shows the influence of microjets in the erosion mechanism

POVERTY IN RURAL INDIA: CASTE AND TRIBE

This paper analyzes the determinants of rural poverty in India, contrasting the situation of scheduled caste (SC) and scheduled tribe (ST) households with the non-scheduled population. The incidence of poverty in SC and ST households is much higher than among non-scheduled households. By combining regression estimates for the ratio of per capita expenditure to the poverty line and an Oaxaca-type decomposition analysis, we study how these differences in the incidence of poverty arise. We find that for SC households, differences in characteristics explain the gaps in poverty incidence more than differences in transformed regression coefficients. In contrast, for ST households, differences in the transformed regression coefficients play the more important role. Copyright 2008 The Authors.