1,599 research outputs found

    Dynamics of evaporative colloidal patterning

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    Drying suspensions often leave behind complex patterns of particulates, as might be seen in the coffee stains on a table. Here we consider the dynamics of periodic band or uniform solid film formation on a vertical plate suspended partially in a drying colloidal solution. Direct observations allow us to visualize the dynamics of the band and film deposition, and the transition in between when the colloidal concentration is varied. A minimal theory of the liquid meniscus motion along the plate reveals the dynamics of the banding and its transition to the filming as a function of the ratio of deposition and evaporation rates. We also provide a complementary multiphase model of colloids dissolved in the liquid, which couples the inhomogeneous evaporation at the evolving meniscus to the fluid and particulate flows and the transition from a dilute suspension to a porous plug. This allows us to determine the concentration dependence of the bandwidth and the deposition rate. Together, our findings allow for the control of drying-induced patterning as a function of the colloidal concentration and evaporation rate.Comment: 11 pages, 7 figures, 2 table

    Predicting Mortality in Children With Pediatric Acute Respiratory Distress Syndrome: A Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology Study

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    OBJECTIVES: Pediatric acute respiratory distress syndrome is heterogeneous, with a paucity of risk stratification tools to assist with trial design. We aimed to develop and validate mortality prediction models for patients with pediatric acute respiratory distress syndrome. DESIGN: Leveraging additional data collection from a preplanned ancillary study (Version 1) of the multinational Pediatric Acute Respiratory Distress syndrome Incidence and Epidemiology study, we identified predictors of mortality. Separate models were built for the entire Version 1 cohort, for the cohort excluding neurologic deaths, for intubated subjects, and for intubated subjects excluding neurologic deaths. Models were externally validated in a cohort of intubated pediatric acute respiratory distress syndrome patients from the Children\u27s Hospital of Philadelphia. SETTING: The derivation cohort represented 100 centers worldwide; the validation cohort was from Children\u27s Hospital of Philadelphia. PATIENTS: There were 624 and 640 subjects in the derivation and validation cohorts, respectively. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The model for the full cohort included immunocompromised status, Pediatric Logistic Organ Dysfunction 2 score, day 0 vasopressor-inotrope score and fluid balance, and PaO2/FIO2 6 hours after pediatric acute respiratory distress syndrome onset. This model had good discrimination (area under the receiver operating characteristic curve 0.82), calibration, and internal validation. Models excluding neurologic deaths, for intubated subjects, and for intubated subjects excluding neurologic deaths also demonstrated good discrimination (all area under the receiver operating characteristic curve \u3e /= 0.84) and calibration. In the validation cohort, models for intubated pediatric acute respiratory distress syndrome (including and excluding neurologic deaths) had excellent discrimination (both area under the receiver operating characteristic curve \u3e /= 0.85), but poor calibration. After revision, the model for all intubated subjects remained miscalibrated, whereas the model excluding neurologic deaths showed perfect calibration. Mortality models also stratified ventilator-free days at 28 days in both derivation and validation cohorts. CONCLUSIONS: We describe predictive models for mortality in pediatric acute respiratory distress syndrome using readily available variables from day 0 of pediatric acute respiratory distress syndrome which outperform severity of illness scores and which demonstrate utility for composite outcomes such as ventilator-free days. Models can assist with risk stratification for clinical trials

    Recent Developments in the Law of the Seas III: A Synopis

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    This third synopsis is part of our continuing effort to present annually a summary of legally significant events of relevance to the law of the seas. This synopsis encompasses events which occurred between March 1, 1971, and February 1, 1972. Primary resources utilized included the New York Times, the Environment Reporter, the United States Code Congressional and Administrative News and the Congressional Record. The almost daily incidence of new developments evidences the growth of concern at local, national and international levels for rational planning in the use and development of the ocean and its resources. With the approach of the Third United Nations Conference on the Law of the Seas in 1973, attention is being focused even more sharply on the law of the sea and its importance to man\u27s future. It is our hope that this third annual synopsis will prove of benefit to all who have an interest in this vital area

    A sensor aided H.264 encoder tested on aerial imagery for SFM

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    Email Print Request Permissions Standard video coding systems currently employed in UAV (Unmanned Aerial Vehicle) and aerial drone applications do not rely on some peculiarities in terms of scene 3D model and correlation among successive frames. In particular, the observed scene is static, i.e. the camera movement is dominant, and it can often be well approximated with a plane. Moreover, camera position and orientation can be obtained from the navigation system. Therefore, correspondent points on two video frames are linked by a simple homography. This paper presents novel results obtained by a low-complexity sensor aided H.264 encoder, recently developed at CIRA and yet tested on simulated data. The proposed encoder employs a new motion estimation scheme which make use of the global motion information provided by the onboard navigation system. The homography is used in order to initialize the block matching algorithm allowing a more robust motion estimation and a smaller search window, and hence reducing the complexity. The tests are made coding real aerial imagery, captured to be used for 3D scene reconstruction. The images are acquired by an high resolution camera mounted on a small drone, flying at low altitude

    PARQUE MUNICIPAL CINTURÃO VERDE DE CIANORTE – MÓDULO MANDHUY E OS PRINCIPAIS IMPACTOS DA ÁREA DE ENTORNO

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    O presente estudo buscou realizar uma análise geográfica a respeito das condições ambientais do Módulo Mandhuy, parte do Parque Municipal Cinturão Verde de Cianorte, localizado no Município de Cianorte-PR. Para tanto, foram investigados os processos de constituição da área de estudo, que esteve diretamente relacionado à ação de colonização da CMNP, quando realizou o planejamento do Município de Cianorte e também do seu núcleo urbano. A CMNP manteve algumas manchas de vegetação original nas proximidades e na área urbana, que mais tarde foram transformadas em áreas de preservação. Essas áreas de vegetação nativa formam quase um círculo ao redor da cidade, levando a denominação de “cinturão verde”. A metodologia utilizada para a construção desse estudo, amparou-se na busca de material bibliográfico relacionado à questão da preservação em Unidades de Conservação, sob o enfoque da Geografia Socioambiental. Em complementação a este material, foram realizadas investigações sistemáticas de campo, com auxilio de material cartográfico, buscando obter dado que pudesse identificar as pressões imprimidas a área pelos moradores das áreas vizinhas, próprias do contexto urbano

    Identification of Hibernating Myocardium: Comparative Accuracy of Myocardial Contrast Echocardiography, Rest-Redistribution Thallium-201 Tomography and Dobutamine Echocardiography

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    AbstractObjectives. We sought to evaluate the comparative accuracy of myocardial contrast echocardiography (MCE), quantitative rest-redistribution thallium-201 (Tl-201) tomography and low and high dose (up to 40 μg/kg body weight per min) dobutamine echocardiography (DE) in identifying myocardial hibernation.Background. Myocardial contrast echocardiography can assess myocardial perfusion and may therefore be useful in predicting myocardial hibernation. However, its accuracy in comparison to myocardial perfusion scintigraphy and to that of high dose DE remains to be investigated.Methods. Eighteen patients (aged [±SD] 57 ± 10 years) with stable coronary artery disease and ventricular dysfunction underwent the above three modalities before coronary revascularization. Myocardial contrast echocardiography was achieved with intracoronary Albunex. Rest echocardiographic and Tl-201 studies were repeated ≥6 weeks after revascularization.Results. Of 109 revascularized segments with severe dysfunction, 46 (42%) improved. Left ventricular ejection fraction increased from 38 ± 14% to 45 ± 13% at follow-up (p = 0.003). Rest Tl-201 uptake and the ratio of peak contrast intensity of dysfunctional to normal segments with MCE were higher (p < 0.01) in segments that recovered function compared with those that did not. Myocardial contrast echocardiography, thallium scintigraphy and any contractile reserve during DE had a similar sensitivity (89% to 91%) with a lower specificity (43% to 66%) for recovery of function. A biphasic response during DE was the most specific (83%) and the least sensitive (68%) (p < 0.01). The best concordance with MCE was Tl-201 (80%, kappa 0.57). Changes in ejection fraction after revascularization related significantly to the number of viable dysfunctional segments by all modalities (r = 0.54 to 0.65).Conclusions. In myocardial hibernation, methods evaluating rest perfusion (MCE, Tl-201) or any contractile reserve have a similar high sensitivity but a low specificity for predicting recovery of function. A limited contractile reserve (biphasic response) increases the specificity of DE. Importantly, the three techniques identified all patients who had significant improvement in global ventricular function.(J Am Coll Cardiol 1997;29:985–93)© 1997 by the American College of Cardiolog

    Use of Coconut COIR in Fiber Reinforced Concrete, Soil and Lime

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    The use of lime as a binder and natural fibers as reinforcements have been in use since ancient human history. However, ordinary Portland cement and concrete have substituted these comparatively cheaper eco-friendlier materials due to their quick setting and strength parameters since the 19th century. However, their large-scale impact on the environment due to greenhouse gases emission has encouraged further research to develop novel composite materials comprising natural fibers like coconut coir and lime as partial cement substitute. In this review study, contemporary research studies conducted by different researchers were explored and has found this field quite encouraging and progressive for modern trends in construction materials. Coir is a material with great potential due to its high strength and ductility comparable to steel; the use of lime or saline treated coir in cement by 1% as optimum quantity and in some cases up to 2% quantity, enhanced the compressive, tensile and flexural strengths up to 5%-20%. Ductility and flexibility of concrete improved with more energy absorption capacity. However, more use of coir did not improve engineering properties of concrete rather deteriorated after 2% use by weight of cement. 1% to 2% coir use in expensive marine soil augmented by 5% use of lime revealed considerable increase in engineering properties of soil especially increase of compressive strength by 1.5 times, increase of compaction factor and plasticity and reduction in shrinkage and liquid limit thus supporting a fruitful use of coir and lime mixture in its properties enhancement. Coir being a natural fiber has a limitation of lesser degradation life so needs to be treated with some suitable natural coating material to enhance its life from 3 to 20 years and needs to be cleaned properly by soaking in lime or saline water to remove lignin, pith, cellulose and silicate crystals. The overall use of coir and lime as substituent of cement binders is highly recommended though further research is required to maximize usage for this economical and eco-friendly material

    A Review of the Utilisation of Hydrated Lime (CL-90) in Engineering Applications and it’s Sustainability Implications

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    Lime is one of the widely used materials in several industries, with an estimated production of 430 million tons worldwide, with the iron, steel and metal industries as the leader, using 250 million tons, followed by the construction industry using around 75 million tons and the chemical industry with 55 million tons usage per annum worldwide. The broadly used types of lime are quick lime CaO (CL90 Q), hydrated lime Ca(OH)2 (CL90 S), hydraulic lime and lime putty. The primary purpose of hydrated lime is to induce alkalinity and use it as filler material to control porosity. Hydrated lime, unlike hydraulic lime, does not exhibit much-cementing properties on mixing with water. Therefore, it requires blending with suitable binders like cement, pozzolans, and bitumen to acquire better binding characteristics. Hydrated lime is widely used in the iron and steel industry as a cheap, sustainable material for converting iron into pig iron and steel and improving the durability of refractories in the blast furnace. The agriculture and food industry also relies heavily on hydrated lime to be used as a purifying flocculating coagulating agent, especially in the sugar industry. The hydrated lime acts as an alkali activator, deodorising and anti-bacterial chemical in treating wastewater/sludge, agricultural fields and environmental protection. The hydrated lime is used to treat wet, marine and cohesive expansive clayey soils as it absorbs moisture and improves engineering properties like compressibility, strength, plasticity, bearing capacity, consistency, sheer strength and shrinkage etc. One of the main usages of hydrated lime in civil engineering applications is in cement- based mortars as a plasticiser. Therefore, the hydrated lime can be recommended for use in diverse industries and multi-purpose roles

    Bovine Follicular Dynamics, Oocyte Recovery,and Development of Oocytes Microinjected with a Green Fluorescent Protein Construct

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    The present study was carried out to 1) evaluate the viability of in vitro fertilized zygotes after microinjection of DNA, 2) assess the influence of oocyte quality upon the development rate of embryos when injected with DNA, and 3) determine the integration frequency of green fluorescent protein DNA into microinjected embryos. Oocytes were aspirated from ovaries of nine nonlactating Holsteins and were categorized into grades A, B, C, and D. At 16 h after in vitro fertilization, approximately half of the pronuclear stage presumptive zygotes were classified as having 1 pronucleus or 2 pronuclei, and they were microinjected with DNA constructs. A potential predictor of DNA integration frequency at d 10 was assessment of the incidence of green fluorescing embryos. The proportion of cleaved embryos that developed to morulae or blastocysts was not different between groups with 1 pronucleus injected (45%), 1 pronucleus uninjected (64%), or 2 pronuclei injected (49%). However, the development of morulae or blastocysts was higher in the group with 2 pronuclei uninjected (69%). The overall developmental score of green fluorescent protein-positive embryos was higher for grade A oocytes (1.3 &#;&#;0.1) than for grade B (0.8 &#; 0.1), C (0.6 &#;&#;0.1), or D (0.3 &#;&#;0.1) oocytes. The results show that production of transgenic bovine blastocysts can occur from the microinjection of a presumptive zygote having only one visible pronucleus. Initial oocyte quality is an important factor in selection of oocytes suitable for microinjection of DNA and for preimplantation development to produce bovine transgenic embryos

    Fundamental Phenomena on Fuel Decomposition and Boundary-Layer Combustion Precesses with Applications to Hybrid Rocket Motors

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    This final report summarizes the major findings on the subject of 'Fundamental Phenomena on Fuel Decomposition and Boundary-Layer Combustion Processes with Applications to Hybrid Rocket Motors', performed from 1 April 1994 to 30 June 1996. Both experimental results from Task 1 and theoretical/numerical results from Task 2 are reported here in two parts. Part 1 covers the experimental work performed and describes the test facility setup, data reduction techniques employed, and results of the test firings, including effects of operating conditions and fuel additives on solid fuel regression rate and thermal profiles of the condensed phase. Part 2 concerns the theoretical/numerical work. It covers physical modeling of the combustion processes including gas/surface coupling, and radiation effect on regression rate. The numerical solution of the flowfield structure and condensed phase regression behavior are presented. Experimental data from the test firings were used for numerical model validation
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