2,715 research outputs found
Computational method to predict thermodynamic, transport, and flow properties for the modified Langley 8-foot high-temperature tunnel
The Langley 8 foot high temperature tunnel (8 ft HTT) is used to test components of hypersonic vehicles for aerothermal loads definition and structural component verification. The test medium of the 8 ft HTT is obtained by burning a mixture of methane and air under high pressure; the combustion products are expanded through an axisymmetric conical contoured nozzle to simulate atmospheric flight at Mach 7. This facility was modified to raise the oxygen content of the test medium to match that of air and to include Mach 4 and Mach 5 capabilities. These modifications will facilitate the testing of hypersonic air breathing propulsion systems for a wide range of flight conditions. A computational method to predict the thermodynamic, transport, and flow properties of the equilibrium chemically reacting oxygen enriched methane-air combustion products was implemented in a computer code. This code calculates the fuel, air, and oxygen mass flow rates and test section flow properties for Mach 7, 5, and 4 nozzle configurations for given combustor and mixer conditions. Salient features of the 8 ft HTT are described, and some of the predicted tunnel operational characteristics are presented in the carpet plots to assist users in preparing test plans
Gut microflora of some edible crabs from Porto Novo Coast
399-401Gut microflora of 5 commercially important crabs, viz. Charybdis cruciata (Herbst), Podophthalmus vigil (Fabricius) (marine), Scylla serrata (Forskal), Portumus pelagicus (Linnaeus), Podophthalmus sanguinolentus (Herbst) (estuarine), were studied. The midgut harboured highest aerobic and proteolytic bacteria. Luminescent bacterial flora were predominant in the hindgut and on the cuticular membrane of all the crabs examined. High numbers of heterotrophic bacteria were recorded in the midgut of Scylla serrata
Diversity analysis and identification of sources resistant to downy mildew, shoot fly and stem borer in wild sorghums
Amniotic fluid embolism: a comprehensive review
Amniotic Fluid Embolism (AFE) is an obstetric catastrophe which occurs in 1 in 8000-80000 deliveries.1 It presents with shortness of breath, hypotension, hypoxemia, uterine atony, post-partum hemorrhage, disseminated intravascular coagulation, convulsions, coma and death. Pathophysiology is not clearly understood. It may be due to anaphylactoid like reaction to fetal cells that enter maternal circulation. There are no proven risk factors though a few have been postulated. Treatment is mainly supportive. The corner stone of management is a multi-disciplinary approach with support given to the failing organ systems. The mortality and morbidity due to AFE is very high. Hence prompt diagnosis and effective supportive measures is the key in the management
Bioactivities of extracts from the marine sponge Halichondria panicea
In the present study, we screened the biological activity of extracts from the marine sponge Halichondria panicea collected in the Arabian Sea. Crude toxin was obtained by methanol, chloroform-methanol (2:1) and aqueous extraction. Subsequently, the protein concentration of each crude extract was determined. The impact of both sponge methanolic and aqueous extracts was found to increase activities of Na+-K+ ATP-ase and Mg++ ATP-ase. In the case of chloroform-methanol extract, higher concentrations increased acetylcholine esterase (AchE) activity. The methanolic and chloroform-methanol extracts exhibited hemolytic activity on chicken and human erythrocytes, whereas the aqueous extract failed to do so. Methanol and aqueous extracts produced an immunostimulating effect and all extracts revealed angiogenic activity. The aqueous extract yielded nine bands by SDS-PAGE on 12% gel
From event analysis to global lessons: disaster forensics for building resilience
With unprecedented growth in disaster risk, there is an urgent need for enhanced learning about and understanding disasters, particularly in relation to the trends in the drivers of increasing risk. Building on the disaster forensics field, we introduce the Post Event Review Capability (PERC) methodology for systematically and holistically analyzing disaster events, and identifying actionable recommendations. PERC responds to a need for learning about the successes and failures in disaster risk management and resilience, and uncovers the underlying drivers of increasing risk. We draw generalizable insights identified from seven applications of the methodology to date, where we find that across the globe policy makers and practitioners in disaster risk management face strikingly similar challenges despite variations in context, indicating encouraging potential for mutual learning. These lessons highlight the importance of integrated risk reduction strategies. We invite others to utilize the freely available PERC approach and contribute to building a repository of learnings on disaster risk management and resilience.
This discussion paper is under review for the journal Natural Hazards and Earth System Sciences (NHESS)
Intrusion Detection Systems for Community Wireless Mesh Networks
Wireless mesh networks are being increasingly used to provide affordable network connectivity to communities where wired deployment strategies are either not possible or are prohibitively expensive. Unfortunately, computer networks (including mesh networks) are frequently being exploited by increasingly profit-driven and insidious attackers, which can affect their utility for legitimate use. In response to this, a number of countermeasures have been developed, including intrusion detection systems that aim to detect anomalous behaviour caused by attacks. We present a set of socio-technical challenges associated with developing an intrusion detection system for a community wireless mesh network. The attack space on a mesh network is particularly large; we motivate the need for and describe the challenges of adopting an asset-driven approach to managing this space. Finally, we present an initial design of a modular architecture for intrusion detection, highlighting how it addresses the identified challenges
CHARACTERIZATION OF OUTER SPACE RADIATION INDUCED CHANGES IN EXTREMOPHILES UTILIZING DEEP SPACE GATEWAY OPPORTUNITIES.
Early integration of science and exploration
concerns into the design of the Deep Space
Gateway (DSG) is essential to maximizing its science
and exploration potential. The proposed concept, characterization
of outer space radiation induced changes
in microbial extremophiles, requires the DSG as infrastructure
supplying power, communications, etc. to
otherwise autonomous systems. Survival and proliferation
of life beyond low earth orbit (LBLEO) can be
accomplished by exposing extremophilic microorganisms
in outer space radiation (OSR) conditions using
DSG system. Extremophilic microbial survival, adaptation,
biological functions, and molecular mechanisms
associated with outer space radiation can be tested by
exposing them onto DSG hardware (inside/outside)
utilizing the traditional microbiology methods and
state-of-the-art molecular biology techniques
Transforming resilience-building today for sustainable futures tomorrow
Addressing increasingly profound vulnerabilities and risks requires a step change away from piecemeal fixes often focused around preparedness and post-disaster recovery towards transformational interventions and measures that focus on creating systemic shifts that challenge underlying vulnerabilities and governance gaps from the design phase itself.
IIASA and ISET in the project “Transformation and Resilience” conducted with the Zurich Flood Resilience Alliance and other initiatives respond to the evident need to reform climate and disaster risk management towards transformational approaches. In this working paper, we reviewed efforts to respond to this evident need, drawing on key findings from the forthcoming book “Transformation and Disaster Resilience” (Springer, forthcoming) to provide a practical stock-take of what transformational risk management (adaptation) is, deep dive into examples of transformational interventions and uncover barriers and enablers for getting transformational resilience-building underway in diverse contexts.
We found that while there are diverse entry points for transformational resilience-building, they share a combination of (some of) the following interlinked pathways: i) Operationalizing innovative approaches and solutions; ii) Delivering integrated intervention packages; iii) Establishing participatory governance models; and iv) Scaling successful pilots, along with a strong commitment to delivering on achieving transformation by setting it as their goal from the start, consequently designing their resilience-building measures and interventions with transformation as their guiding star.
We also found that whether interventions and measures designed for transformational change will deliver on their objective strongly hinges on creating appropriate enabling environments, which include i) learning and knowledge platforms and experiential niche learning and continuous feedback loops; ii) aligning transformational change objectives with strategic government priorities to harness and foster political will and moment; as well as iii) unlocking the transformational potential of bottom-up governance grounded in local contexts; together with iv) establishing the necessary framework conditions for phased, long-term programs; and v) committing sufficient financial outlays to initiatives designed with transformational change in mind
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