Modeling of steady plane thermal detonations

Steady plane thermal detonations proceeding through coarse fuel-coolant mixtures have been predicted to exhibit pressures of approximately 10/sup 4/ bar for UO/sub 2//Na and approximately 10/sup 3/ bar for Sn/H/sub 2/O/sup 1/. Although detailed experimental information for the crucial fragmentation step is still largely lacking, some important preliminary conclusions can nevertheless be drawn from a detailed examination of the jump balances and solution of the steady, separated-flow conservation equations in the fragmentation zone behind the shock. A few key results are presented of some parametric calculations of steady plane thermal detonations, and in addition offer some broader comments. 33 references

Fuel-coolant interaction in a shock tube with initially-established film boiling. [PWR; BWR]

A new mode of thermal interaction has been employed, in which liquid metal is melted in a crucible within a shock tube; the coolant level is raised to overflow the crucible and establish subcooled film boiling with known bulk metal temperature; and a pressure shock is then initiated. With water and lead-tin alloy an initial splash of metal may be obtained after the vapor film has collapsed, due primarily to thermal interaction, followed by a successive cycle of bubble growth and collapse. To obtain large interactions, the interfacial contact temperature must exceed the spontaneous nucleation temperature of the coolant. Other cutoff behavior is observed with respect to the initial system pressure and temperatures and with the shock pressure and rise time. Experiments with butanol and lead-tin alloy show only relatively mild interactions. Qualitative explanations are proposed for the different behaviors of the two liquids

Heat transfer from bubbling pools. Progress report, July 1, 1975--October 1, 1975

It is shown that the heat transfer characteristics of volume-heated boiling pools can be successfully modeled by non-boiling pools with internal gas injection. The strong influence of spatial distribution of bubble sites is relevant to estimates of boiling fuel attack on gas-releasing sacrificial materials. (auth

Land use change in a pericolonial society: intensification and diversification in Ifugao, Philippines between 1570 and 1800 CE

Land use modelling is increasingly used by archaeologists and palaeoecologists seeking to quantify and compare the changing influence of humans on the environment. In Southeast Asia, the intensification of rice agriculture and the arrival of European colonizers have both been seen as major catalysts for deforestation, soil erosion, and biodiversity change. Here we consider the Tuwali-Ifugao people of the Cordillera Central (Luzon, Philippines), who resisted Spanish colonial subjugation from the 16th to the mid-nineteenth century, in part through the development of a world-renowned system of intensive wet-rice terrace agriculture. To quantify changes in how the Tuwali-Ifugao used their environment, we model land use in Old Kiyyangan Village, a long-inhabited settlement, at two timepoints: circa 1570 CE, prior to the Spanish arrival in Luzon, and circa 1800 CE, before the village was sacked by Spanish military expeditions. Our model demonstrates that between 1570 and 1800 the adoption of rice as a staple and the corresponding expansion in terrace agriculture, along with a general diversification of diet and land use, enabled the village’s population to double without increasing total land use area. Further, this major intensification led to the solidification of social hierarchies and occurred without a proportional increase in deforestation.Introduction Methodology - Models in Ifugao: The History and Socio-Ecology of the Region - The Historical Land Use Model - Model Calculations for OKV - Population and Boble (Settled Area) at OKV - Payo (Terraces) - Uma (Swidden Fields) - Muyong (Private Forests) - Domesticated Animals - Hunting, Foraging, and Fishing - Fuel and Resource Extraction - Commerce - Agricultural Productivity and Nutritional Value - Dietary Proportions Results - 1800 - 1570 - Exploring Social Difference: Kadangyan and Nawotwot Land Use in 1800 Discussio

Levantamento do índice de fatores de risco para doenças crônicas não transmissíveis entre servidores da UNICAMP

Este estudo objetivou identificar e analisar os fatores de risco para hipertensão arterial sistêmica, diabetes mellitus e doenças cardiovasculares entre servidores da Unicamp - Campinas-SP. Preencheram a ficha de anamnese inicial 1300 servidores, sendo 783 do sexo feminino e 517 do sexo masculino, idade entre 30 a 58 anos, num período de julho de 2005 a setembro de 2008, obtendo-se dados referentes ao nome, idade, sexo, IMC, uso de tabaco, etilismo, sedentarismo e histórico familiar de HAS, hipercolesterolemia e evento isquêmico. Após aplicação da anamnese, os servidores que apresentavam três ou mais fatores de risco para HAS, DM e DCV foram orientados e encaminhados para realização da avaliação antropométrica, mensuração da pressão arterial e glicosimetria capilar no Cecom-Unicamp e postos de saúde e até hospitais. Os resultados apontaram que 70,3% dos servidores não realizavam atividade física no momento da coleta, 76,2% apresentaram pressão arterial de 130/80 a 140/100 mmHg, 32,1% dos sujeitos apresentaram antecedentes familiares para DM, 60,5% para hipercolesterolemia, 52,0% para evento isquêmico prévio, destes 75,5% apresentaram sobrepeso e 15,9% obesidade grau I. Os resultados indicam a urgência e a necessidade da disseminação de informações educativas na universidade, visando à educação em saúde e prevenção de fatores de risco e doenças crônicas não-transmissíveis entre os servidores da universidade, bem como a continuidade dos trabalhos oferecidos pelo Programa Mexa-se nas unidades de ensino, pesquisa e extensão e nas áreas de saúde e outras

Drivers and sustainability of bird hunting in Madagascar

Bird conservation depends on robust data on the densities of and threats to each species, and an understanding of the choices and incentives of bird hunters. This first comprehensive study of bird hunting and its effects in Madagascar uses 8 years of data on 87 bird species to determine bird densities and hunting pressure, incentives, choices, methods, spatial variation, and sustainability on the Masoala Peninsula of Madagascar. We find that bird hunting is common, affecting human wellbeing and, for some species, long-term population viability. Hunters caught more abundant species of lower trophic levels and consumers preferred the flavor of abundant granivores and nectarivores, while they disliked carnivores, scavengers, and species with common cultural proscriptions. Wealth increased species selectivity among consumers, whereas food insecurity increased hunting pressure overall. Projected and documented declines in at least three species are concerning, qualifying at least two for increased IUCN threatened species categories. We provide novel, data-driven assessments of hunting's threat to Madagascar's birds, identify key species of concern, and suggest both species- and consumer-specific conservation actions

The Social and Political Dimensions of the Ebola Response: Global Inequality, Climate Change, and Infectious Disease

The 2014 Ebola crisis has highlighted public-health vulnerabilities in Liberia, Sierra Leone, and Guinea – countries ravaged by extreme poverty, deforestation and mining-related disruption of livelihoods and ecosystems, and bloody civil wars in the cases of Liberia and Sierra Leone. Ebola’s emergence and impact are grounded in the legacy of colonialism and its creation of enduring inequalities within African nations and globally, via neoliberalism and the Washington Consensus. Recent experiences with new and emerging diseases such as SARS and various strains of HN influenzas have demonstrated the effectiveness of a coordinated local and global public health and education-oriented response to contain epidemics. To what extent is international assistance to fight Ebola strengthening local public health and medical capacity in a sustainable way, so that other emerging disease threats, which are accelerating with climate change, may be met successfully? This chapter considers the wide-ranging socio-political, medical, legal and environmental factors that have contributed to the rapid spread of Ebola, with particular emphasis on the politics of the global and public health response and the role of gender, social inequality, colonialism and racism as they relate to the mobilization and establishment of the public health infrastructure required to combat Ebola and other emerging diseases in times of climate change

Linear and nonlinear instability in vertical counter-current laminar gas-liquid flows

We consider the genesis and dynamics of interfacial instability in gas-liquid flows, using as a model the two-dimensional channel flow of a thin falling film sheared by counter-current gas. The methodology is linear stability theory (Orr-Sommerfeld analysis) together with direct numerical simulation of the two-phase flow in the case of nonlinear disturbances. We investigate the influence of three main flow parameters (density contrast between liquid and gas, film thickness, pressure drop applied to drive the gas stream) on the interfacial dynamics. Energy budget analyses based on the Orr-Sommerfeld theory reveal various coexisting unstable modes (interfacial, shear, internal) in the case of high density contrasts, which results in mode coalescence and mode competition, but only one dynamically relevant unstable internal mode for low density contrast. The same linear stability approach provides a quantitative prediction for the onset of (partial) liquid flow reversal in terms of the gas and liquid flow rates. A study of absolute and convective instability for low density contrast shows that the system is absolutely unstable for all but two narrow regions of the investigated parameter space. Direct numerical simulations of the same system (low density contrast) show that linear theory holds up remarkably well upon the onset of large-amplitude waves as well as the existence of weakly nonlinear waves. In comparison, for high density contrasts corresponding more closely to an air-water-type system, although the linear stability theory is successful at determining the most-dominant features in the interfacial wave dynamics at early-to-intermediate times, the short waves selected by the linear theory undergo secondary instability and the wave train is no longer regular but rather exhibits chaotic dynamics and eventually, wave overturning.Comment: 30 pages, 14 figure