Instability of multistage compressor K1501

The K1501 compressor, driven by a steam turbine, is used to transport synthetic gas in fertilizer plants of 1000 tons daily production. The turbo-compressor set, which had been in operation since 1982, vibrated rather intensely, and its maximum load was only about 95 percent of the normal value. Damaging vibration to pads and gas-sealing labyrinths occurred three times from 1982 to 1983 and resulted in considerable economic loss. From the characteristics of the vibration, we suspected its cause to be rotor instability due to labyrinth-seal excitation. But, for lack of experience, the problem was not addressed for two years. Finally, we determined that the instability was indeed produced by labyrinth-seal excitation and corrected this problem by injecting gas into the middle-diaphragm labyrinths. This paper primarily discusses the failure and the remedy described above

The role of elected and appointed village leaders in the allocation of public resources: Evidence from a low-income region in China

appointed leader, election, Public goods,

Gender difference in the long-term impact of famine:

"An increasing literature examines the association between restricted fetal or early childhood growth and the incidence of diseases in adulthood. Little is known, however, about gender difference in this association. We assess the impact of nutritional deficiency in the early lives of survivors of the Chinese Great Famine in terms of health and economic welfare, paying special attention to gender differences. We found evidence of several significant negative impacts for female�but not male�survivors, and the gender differences are statistically significant. Furthermore, we show that the selection bias caused by differences in mortality plausibly explains more than two-thirds of the documented gender difference in the long-term health of famine survivors." from Author's AbstractFamine, Fetal origins hypothesis, Gender difference, Health and nutrition,

Rural roads and poor area development in Vietnam

The authors assess impacts of rural road rehabilitation on market development at the commune level in rural Vietnam and examine the variance of those impacts and the geographic, community, and household factors that explains it. Double difference and matching methods are used to address sources of selection bias in identifying impacts. The results point to significant average impacts on the development of local markets. They also uncover evidence of considerable impact heterogeneity, with a tendency for poorer communes to have higher impacts due to lower levels of initial market development. Yet, poor areas are also saddled with other attributes that reduce those impacts.Transport Economics Policy&Planning,Housing&Human Habitats,Debt Markets,Markets and Market Access,Economic Theory&Research

Fungibility and the flypaper effect of project aid : micro-evidence for Vietnam

While most economists assume that aid is fungible, most aid donors behave as if it is not. The authors study recipient government responses to development project aid in the context of a specific World Bank-financed project. They estimate the impact of a rural road rehabilitation project in Vietnam on the kilometers of roads actually rehabilitated and built. Using local-level survey data collected for this purpose, the authors test whether the evidence supports the standard economic argument that there will be little or no impact on rural roads rehabilitated, given fungibility. They find evidence that, although project aid impacts on rehabilitated road kilometers were less than intended, more roads were built in project areas. The results suggest that there was fungibility within the sector, but that aid largely stuck to that sector.Transport Economics Policy&Planning,Rural Roads&Transport,Rural Transport,Roads&Highways,Housing&Human Habitats

Left behind to farm ? women's labor re-allocation in rural China

The transformation of work during China’s rapid economic development is associated with a substantial but little noticed re-allocation of traditional farm labor among women, with some doing much less and some much more. This paper studies how the work, time allocation, and health of non-migrant women are affected by the out-migration of others in their household. The analysis finds that the women left behind are doing more farm work than would have otherwise been the case. There is also evidence that this is a persistent effect, and not just temporary re-allocation. For some types of women (notably older women), the labor re-allocation response comes out of their leisure.Population Policies,Health Monitoring&Evaluation,Gender and Development,Anthropology,Population&Development

Are there lasting impacts of aid to poor areas ? Evidence from rural China

The paper revisits the siteof a large, World Bank-financed, rural development program in China 10 years after it began and four years after disbursements ended. The program emphasized community participation in multi-sectoral interventions (including farming, animal husbandry, infrastructure and social services). Data were collected on 2,000 households in project and nonproject areas, spanning 10 years. A double-difference estimator of the program's impact (on top of pre-existing governmental programs) reveals sizeable short-term income gains that were mostly saved. Only modest gains to mean consumption emerged in the longer term-in rough accord with the gain to permanent income. Certain types of households gained more than others. The educated poor were under-covered by the community-based selection process-greatly reducing overall impact. The main results are robust to corrections for various sources of selection bias, including village targeting and interference due to spillover effects generated by the response of local governments to the external aid.Rural Poverty Reduction,Access to Finance,,Poverty Monitoring&Analysis,Economic Theory&Research

Evidence for Two Gaps and Breakdown of the Uemura Plot in Ba0.6_{0.6}K0.4_{0.4}Fe2_2As2_2 Single Crystals

We report a detailed investigation on the lower critical field $H_{c1}$ of the superconducting Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ (FeAs-122) single crystals. A pronounced kink is observed on the $H_{c1}(T)$ curve, which is attributed to the existence of two superconducting gaps. By fitting the data $H_{c1}(T)$ to the two-gap BCS model in full temperature region, a small gap of $\Delta_a(0)=2.0\pm 0.3$ meV and a large gap of $\Delta_b(0)=8.9\pm 0.4$ meV are obtained. The in-plane penetration depth $\lambda_{ab}(0)$ is estimated to be 105 nm corresponding to a rather large superfluid density, which points to the breakdown of the Uemura plot in FeAs-122 superconductors.Comment: 5 pages, 4 figure