Download or read book Experimental Impact Dynamics Testing of a Glaciated Water Drop and Quantification of Partial Melting with Varying Residence Time written by Sihong Yan and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: High altitude ice crystals have been recently discovered to be the cause of engine and heated probe icing over high humidity tropical regions. Ice accretion related to partially melted ice crystals was first discovered in 2006 and it is a threat to aviation safety. It is known that ice crystals without any water content do not accrete to surfaces. The classical frame icing theory involving super-cooled water droplets cannot explain the cause of icing inside turbofan engines flying at altitudes where there is no water content, since only fully glaciated ice crystal clouds exist. To understand the icing conditions and physical mechanism of engine icing, research projects like the High Altitude Ice Crystal (HAIC) international project are been conducted, and test facilities, like the National Research Council icing wind tunnel or the NASA Propulsion System Laboratory tunnel, have been constructed. The correlation between engine icing events and mixed-phase icing clouds that partially melt when ingested in an engine has been confirmed in these facilities. Despite the availability of facilities to reproduce the ice accretion events inside engines, fundamental testing of individual partially melted water droplets is not available and the validation of tools to predict partial melting of crystals is not possible. The study of physical processes involved in the partial melting of a single ice crystal can be divided into two parts. The first part is the impact dynamics of the single droplet, and the second part is the melting process of the frozen droplet. Attempts to characterize these two phenomena were conducted at the Adverse Environmental Rotor Test Stand Facility at Penn State. To quantify impact dynamics of ice crystals, high-speed video of single frozen water droplets impacting a surface was acquired. The frozen particles had a diameter ranging from 0.4 mm to 0.9 mm and impacted at velocities varying from 90 m/sec to 309 m/sec. The technique used to freeze the droplets and launch the particles against a surface is described. High-speed video was used to quantify the ice accretion area to the surface for varying impact angles (30, 45, 60), and impacting velocities. An oxygen /acetylene cross-flow flame was used to partially melt the traveling frozen particles and it is also discussed. A linear relationship between impact angle and ice accretion is identified for fully frozen particles. The slope of the relationship is affected by impact speed. Higher impact angles closer to perpendicularity between the surface and the particle trajectory, e.g. 60, exhibited small differences in ice accretion with varying velocities. Increasing velocity from 161 m/sec to 259 m/sec nearly doubled the ice accretion area at a shallower impact angle of 30. The increase accretion area highlights the importance of impact angle and velocity on the accretion process of partially melted ice crystals. It was experimentally observed that partial melting was not a pre-requisite for accretion at the tested velocities when impact angles of 45 and 30 were used. The ice accretion due to impact was observed under five surface temperatures, -20C, -15C, -10C, 0C and 10C. The influence of the surface temperature was qualitatively observed at an impact angle of 30. The temperature varied from -15C to 10C, and a maximum area of ice accretion was observed at surface temperatures surrounding the freezing point of water. A second emphasis of the work was to correlate residence time requirements for the melting of frozen drops. To characterize the melting process of fully glaciated droplets, a luminescent technique was developed to measure the percentage of melting experimentally. Luminescent dye and high-speed camera visualization were used to monitor the partial melting state of an ultrasonically levitated frozen drop exposed to warm environments. Rhodamine B was dissolved (0.01% mass fraction) in the water used to create a droplet. The Droplet was placed at the node of the wave created by the acoustic levitator and frozen via convective cooling. When the cold air flow was turned off, the partial melting of the droplet began. Water droplets with a diameter ranging approximately between 300m to 1800m were tested. Four environmental melting temperatures were tested: 5C, 15C, 25C and 35C. The variation of percentage of partial melting of the drop with time was recorded. The correlation between the rate of melting, environmental temperature, and diameter of the frozen droplets is reported and discussed. It is confirmed that the time rate of melting is inversely proportional to the diameter of the ice crystals and directly proportional to the environmental temperature. An empirical fit to predict the percentage of partial melting with respect to temperature and droplet diameter was experimentally acquired. The models developed in this research can improve the understanding of the physics related to engine icing. In addition, several technologies developed during the effort can be applied to icing wind tunnel testing for the quantification of partial melting.
Download or read book Experimental Evaluation of the Impact Behavior of Partially Melted Ice Particles written by Miguel Alvarez Tiburcio and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Operations in glaciated conditions are a threat to commercial aviation. The ingestionof ice crystals can affect different aircraft probes but can also affect jetengines. As fully frozen ice crystals enter an engine, partial melting occurs onthe low-pressure compressor region of the engine, and ice accretion could occuron warm surfaces due to the presence of water coupled with the cooling capacityof the unfrozen portion found on the particles. Understanding the fundamentalfracture dynamics that occur when partially melted ice crystals impact a surface isneeded for model development and verification. To experimentally measure suchfracture/splashing dynamics, a test rig was designed and fabricated to observethe impacts of partially melted ice particles. Ice particles ranging from 403 m to1028 m were suspended on an ultrasonic levitator and were allowed to melt undernatural convection. A fluorescence-based technique was used to quantify thewater content of the melting ice particle in real time. A pneumatic launcher wasautomatically triggered at a requested water content to ice ratio, and a stainlesssteel impactor was launched at speeds ranging from 2.8ms1 to 65.5ms1. Theimpacts were recorded with a high-speed camera at 75000 frames per second. Thequalitative behavior of these impacts was observed, and an empirical model to determinethe threshold velocity for an ice particle to fracture for four different watercontent to ice ratios was proposed. From this empirical model, when the partialmelting was 79%, the impact velocity required to fracture a particle increased by81% from its value for the fully frozen cases. Moreover, during the data acquisitionprocess, a new technique to measure the water content of a melting ice particlebased on the diameter of the ice core observed post impact for the non-fracturedevents was proposed. This direct measurement technique was compared to thefluorescence-based water content quantification techniques to further understandpartial melting quantification uncertainties.
Download or read book The Effect of Water on Partial Melting in the Upper Mantle written by Travis Jay Tenner and published by . This book was released on 2011-09-09 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents experimental constraints on incipient melting of mantle peridotite under hydrated conditions. High P-T experiments were performed at pressures of 3 to 13 GPa, and at temperatures of 1200--1450C. These experiments measure mineral/melt H2O partitioning and storage capacity of peridotite components, as well as determine melting phase relations and the compositions of partial melts and residues of hydrated peridotite. Incipient melt H2O concentrations are estimated by peridotite/melt H2O partitioning ( Dperidotite/meltH2O ). To parameterize Dperidotite/meltH2O, mineral/melt H2O partition coefficients were determined for all crystalline phases of the peridotite solidus assemblage (Chapter 2). Combining these Dmineral/meltH2O values with corresponding modal abundances along the solidus yields a Dperidotite/meltH2O of 0.005--0.010 from 1 to 5 GPa, which is dependent on pressure due to varying garnet and pyroxene modal abundances, and to variable pyroxene Al content. This Dperidotite/meltH2O range predicts that incipient melts of MORB source (50--200 ppm H2Obulk) and OIB source (300--1000 ppm H2Obulk) upper mantle contain 0.5--3.8 wt.% and 3--20 wt.% dissolved H2O, respectively. The amount of dissolved H2O in incipient melt dictates hydrous solidus depression, Delta T, which ultimately controls the stability of hydrous melts at P and T. This DeltaT-H2 Omelt relationship was investigated at 3.5 GPa by partially melting hydrated peridotite from 1200--1450C (Chapter 3). Mass balance of phases allows for determination of melt fractions (F) from experiments, as well as estimation of H2Omelt. Delta T values are quantified as the difference in melting temperature between dry and wet peridotite at a particular F. Parameterization of DeltaT as a function of H2Omelt predicts that solidus melts with 1.5, 5, 10, and 15 wt.% dissolved H 2O generate DeltaT values of 50, 150, 250, and 300C, respectively. Combination of this paramterization with Dperidotite/meltH2O (Chapter 2) insinuates that 500 ppm H2Obulk is necessary to stabilize melt across the observed seismic low velocity zone (LVZ) beneath oceanic lithosphere, which is significantly greater than the MORB source upper mantle H2Obulk of 50--200 ppm. This observation argues against suggestions that hydrous melting is solely responsible for the LVZ. At higher pressures the aforementioned parameterizations are difficult to constrain experimentally, but the onset of hydrous melting can be determined by the peridotite H2O storage capacity, defined as the maximum H2O concentration that peridotite can store without stabilizing a hydrous fluid or melt. A new method of determining a minerals H2O storage capacity is employed, in which a hydrated monomineralic layer is equilibrated with a layer of hydrated peridotite and a small amount of melt (Chapter 4). Experiments were carried out at conditions near the 410 km transition zone (TZ) depth to investigate hydrous melting due to the H 2O storage capacity contrast between the TZ and upper mantle. Measured olivine and orthopyroxene H2O storage capacities, combined with estimates of garnet H2O storage capacity, and P-dependent lherzolite modes, yields a peridotite H2O storage capacity of 700--1100 ppm directly above 410 km. This is not consistent with pervasive melting above 410 km, as this range is several times greater than MORB source upper mantle H2Obulk. However, regional melting in areas such as H2O-rich OIB source, or areas of recent subduction may likely occur, leaving residues with ∼1000 ppm H2Obulk.
Download or read book Quantification of Glacier Melt Volume in the Indus River Watershed written by Maria Nicole Asay and published by . This book was released on 2011 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: In addition to calculating current melt volumes over large glaciated areas, this model can also be used to determine future melt rates under differing climate scenarios. By applying suggested future regional temperature change to the temperature data, the impact on average melt rate over the watershed was found to increase from 3.02 m/year to 4.69 m/year with up to 2 °C temperature increase. Assuming glacier area remains relatively constant over short time periods, this would amount to a 145 km3 increase in melt volume.
Download or read book The Ocean and Cryosphere in a Changing Climate written by Intergovernmental Panel on Climate Change (IPCC) and published by Cambridge University Press. This book was released on 2022-04-30 with total page 755 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.
Download or read book Natural Climate Variability on Decade to Century Time Scales written by National Research Council and published by National Academies Press. This book was released on 1996-08-30 with total page 645 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reflects the current state of scientific knowledge about natural climate variability on decade-to-century time scales. It covers a wide range of relevant subjects, including the characteristics of the atmosphere and ocean environments as well as the methods used to describe and analyze them, such as proxy data and numerical models. They clearly demonstrate the range, persistence, and magnitude of climate variability as represented by many different indicators. Not only do natural climate variations have important socioeconomic effects, but they must be better understood before possible anthropogenic effects (from greenhouse gas emissions, for instance) can be evaluated. A topical essay introduces each of the disciplines represented, providing the nonscientist with a perspective on the field and linking the papers to the larger issues in climate research. In its conclusions section, the book evaluates progress in the different areas and makes recommendations for the direction and conduct of future climate research. This book, while consisting of technical papers, is also accessible to the interested layperson.
Download or read book Bulletin of the Atomic Scientists written by and published by . This book was released on 1973-10 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
Download or read book Extrusion written by Harold F. Giles Jr and published by William Andrew. This book was released on 2013-09-21 with total page 638 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of Extrusion is designed to aid operators, engineers, and managers in extrusion processing in quickly answering practical day-to-day questions. The first part of the book provides the fundamental principles, for operators and engineers, of polymeric materials extrusion processing in single and twin screw extruders. The next section covers advanced topics including troubleshooting, auxiliary equipment, and coextrusion for operators, engineers, and managers. The final part provides applications case studies in key areas for engineers such as compounding, blown film, extrusion blow molding, coating, foam, and reprocessing. This practical guide to extrusion brings together both equipment and materials processing aspects. It covers basic and advanced topics, for reference and training, in thermoplastics processing in the extruder. Detailed reference data are provided on such important operating conditions as temperatures, start-up procedures, shear rates, pressure drops, and safety. A practical guide to the selection, design and optimization of extrusion processes and equipment Designed to improve production efficiency and product quality Focuses on practical fault analysis and troubleshooting techniques
Download or read book The Glacial World According to Wally written by Wallace S. Broecker and published by . This book was released on 1995 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Research Opportunities in the Earth Sciences written by National Research Council and published by National Academies Press. This book was released on 2012-04-26 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 2001 National Research Council (NRC) report Basic Research Opportunities in Earth Science (BROES) described how basic research in the Earth sciences serves five national imperatives: (1) discovery, use, and conservation of natural resources; (2) characterization and mitigation of natural hazards; (3) geotechnical support of commercial and infrastructure development; (4) stewardship of the environment; and (5) terrestrial surveillance for global security and national defense. This perspective is even more pressing today, and will persist into the future, with ever-growing emphasis. Today's world-with headlines dominated by issues involving fossil fuel and water resources, earthquake and tsunami disasters claiming hundreds of thousands of lives and causing hundreds of billions of dollars in damages, profound environmental changes associated with the evolving climate system, and nuclear weapons proliferation and testing-has many urgent societal issues that need to be informed by sound understanding of the Earth sciences. A national strategy to sustain basic research and training of expertise across the full spectrum of the Earth sciences is motivated by these national imperatives. New Research Opportunities in the Earth Sciences identifies new and emerging research opportunities in the Earth sciences over the next decade, including surface and deep Earth processes and interdisciplinary research with fields such as ocean and atmospheric sciences, biology, engineering, computer science, and social and behavioral sciences. The report also identifies key instrumentation and facilities needed to support these new and emerging research opportunities. The report describes opportunities for increased cooperation in these new and emerging areas between EAR and other government agency programs, industry, and international programs, and suggests new ways that EAR can help train the next generation of Earth scientists, support young investigators, and increase the participation of underrepresented groups in the field.
Download or read book Deep Carbon written by Beth N. Orcutt and published by Cambridge University Press. This book was released on 2019-10-17 with total page 687 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive guide to carbon inside Earth - its quantities, movements, forms, origins, changes over time and impact on planetary processes. This title is also available as Open Access on Cambridge Core.
Download or read book Introduction to Mineralogy and Petrology written by Swapan Kumar Haldar and published by Elsevier. This book was released on 2020-07-29 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction to Mineralogy and Petrology, second edition, presents the essentials of both disciplines through an approach accessible to industry professionals, academic researchers, and students alike. This new edition emphasizes the relationship between rocks and minerals, right from the structures created during rock formation through the economics of mineral deposits. While petrology is classified on the lines of geological evolution and rock formation, mineralogy speaks to the physical and chemical properties, uses, and global occurrences for each mineral, emphasizing the need for the growth of human development. The primary goal is for the reader to identify minerals in all respects, including host-rocks, and mineral deposits, with additional knowledge of mineral-exploration, resource, extraction, process, and ultimate use. To help provide a comprehensive analysis across ethical and socio-economic dimensions, a separate chapter describes the hazards associated with minerals, rocks, and mineral industries, and the consequences to humanity along with remedies and case studies. New to the second edition: includes coverage of minerals and petrology in extra-terrestrial environments as well as case studies on the hazards of the mining industry. Addresses the full scope of core concepts of mineralogy and petrology, including crystal structure, formation and grouping of minerals and soils, definition, origin, structure and classification of igneous, sedimentary and metamorphic rocks Features more than 250 figures, illustrations and color photographs to vividly explore the fundamental principles of mineralogy and petrology Offers a holistic approach to both subjects, beginning with the formation of geologic structures that is followed by the hosting of mineral deposits and the exploration and extraction of lucrative, usable products that improve the health of global economies Includes new content on minerals and petrology in extraterrestrial environments and case studies on hazards in the mining industry
Download or read book Landscapes on the Edge written by National Research Council and published by National Academies Press. This book was released on 2010-04-25 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: During geologic spans of time, Earth's shifting tectonic plates, atmosphere, freezing water, thawing ice, flowing rivers, and evolving life have shaped Earth's surface features. The resulting hills, mountains, valleys, and plains shelter ecosystems that interact with all life and provide a record of Earth surface processes that extend back through Earth's history. Despite rapidly growing scientific knowledge of Earth surface interactions, and the increasing availability of new monitoring technologies, there is still little understanding of how these processes generate and degrade landscapes. Landscapes on the Edge identifies nine grand challenges in this emerging field of study and proposes four high-priority research initiatives. The book poses questions about how our planet's past can tell us about its future, how landscapes record climate and tectonics, and how Earth surface science can contribute to developing a sustainable living surface for future generations.
Download or read book Geomorphology of Proglacial Systems written by Tobias Heckmann and published by Springer. This book was released on 2018-11-29 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the recession of alpine glaciers since the end of the Little Ice Age (LIA), which has been accelerating in the past decades. It provides an overview of the research in the field, presenting definitions and information about the different proglacial areas and systems. A number of case studies are from the PROSA project group which encompasses the expertise of geomorphologists, geologists, glaciologists and geodesists. The PROSA joint project (High-resolution measurements of morphodynamics in rapidly changing PROglacial Systems of the Alps) is determined to tackle the problems of geomorphic activity on sediment export through a quantification of sediment fluxes effected by the aforementioned geomorphic processes within the forefield of the Gepatschferner glacier (Central Alps, Austria).
Download or read book The Glacier Theory written by James David Forbes and published by . This book was released on 1840 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water Quality Assessments written by Deborah V Chapman and published by CRC Press. This book was released on 1996-08-22 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt: This guidebook, now thoroughly updated and revised in its second edition, gives comprehensive advice on the designing and setting up of monitoring programmes for the purpose of providing valid data for water quality assessments in all types of freshwater bodies. It is clearly and concisely written in order to provide the essential information for all agencies and individuals responsible for the water quality.
Download or read book Climate Intervention written by National Research Council and published by National Academies Press. This book was released on 2015-06-23 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: The growing problem of changing environmental conditions caused by climate destabilization is well recognized as one of the defining issues of our time. The root problem is greenhouse gas emissions, and the fundamental solution is curbing those emissions. Climate geoengineering has often been considered to be a "last-ditch" response to climate change, to be used only if climate change damage should produce extreme hardship. Although the likelihood of eventually needing to resort to these efforts grows with every year of inaction on emissions control, there is a lack of information on these ways of potentially intervening in the climate system. As one of a two-book report, this volume of Climate Intervention discusses albedo modification - changing the fraction of incoming solar radiation that reaches the surface. This approach would deliberately modify the energy budget of Earth to produce a cooling designed to compensate for some of the effects of warming associated with greenhouse gas increases. The prospect of large-scale albedo modification raises political and governance issues at national and global levels, as well as ethical concerns. Climate Intervention: Reflecting Sunlight to Cool Earth discusses some of the social, political, and legal issues surrounding these proposed techniques. It is far easier to modify Earth's albedo than to determine whether it should be done or what the consequences might be of such an action. One serious concern is that such an action could be unilaterally undertaken by a small nation or smaller entity for its own benefit without international sanction and regardless of international consequences. Transparency in discussing this subject is critical. In the spirit of that transparency, Climate Intervention: Reflecting Sunlight to Cool Earth was based on peer-reviewed literature and the judgments of the authoring committee; no new research was done as part of this study and all data and information used are from entirely open sources. By helping to bring light to this topic area, this book will help leaders to be far more knowledgeable about the consequences of albedo modification approaches before they face a decision whether or not to use them.
