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Sample records for wind-made ice sculpture

  1. The People's Smart Sculpture

    OpenAIRE

    Koplin, Martin; Nedelkovski, Igor; Salo, Kari

    2016-01-01

    The People’s Smart Sculpture (PS2) panel discusses future oriented approaches in smart media-art, developed, designed and exploited for artistic and public participation in the change and re-design of our living environment. The actual debate about a smart future is not taking into account any idea of media art as an instrument for to realize the social sculpture, mentioned by Beuys [1] or as social sculpture itself. The People’s Smart Sculpture is the only large scale Creative Europe media-a...

  2. Structures in sculptures

    DEFF Research Database (Denmark)

    Vanggaard, Ole

    Conceptual design of structures in architecture involves a dialog between a structural and an architectural concept. The architecture is very often changed in this process. The dialog between the parties are described and well known. It is often very difficult to bridge the gab between...... the different concepts and find a final synthesis, but the problem is known. Large sculptures represent structural challenges. The design of the supports inside the structures reveals often a very different world from the outside view of the sculpture. The piece of art and its structure may have two very...... different lives. A sculpture of today may be very dissimilar from what we have seen earlier. The structure becomes sometimes a visual part of the art. Ultimately, there may not be any distinction between structure and art. The technical demand, the durability and the safety are just as important for a large...

  3. Sculpture Sketches in Bloom

    Science.gov (United States)

    DiJulio, Betsy

    2009-01-01

    The best artistic challenges open students' eyes, hearts, and minds by combining both formal and conceptual concerns. In this article, the author describes a project inspired by a temporary exhibition of African Shona sculpture entitled "Mutambo! (Celebrate!)" at the Norfolk Botanical Gardens in Norfolk, Virginia. (Contains 2 online…

  4. Sculpture Versus Architecture?

    Directory of Open Access Journals (Sweden)

    Alexander Rappaport

    2007-07-01

    Full Text Available Many critics consider Richard Serra the leading sculptor of the 20th century. He is famous not only for inventing something new in sculpture (abstract sculpture compositions existed before him, having been opened by constructivist vanguard of the beginning of the 20th century. Material selections by Vladimir Tatlin and sculptures by Osip Tsadkin, as well as compositions by Henry Moor appeared before Serra. Serra is famous for transferring his works' accent from the works as they are, which could be installed in any place, to their environment. That is he saw in the sculpture a key to understanding the urban space. His crude metal sheets and profiles, rectangular and curvilinear, exceeding regular scale of sculpture, come closer to architecture. Richard Serra places them near architectural constructions as checkpoints of intermediate scale category of space located between so-called «street furniture» – lamp posts, stalls, fountains and benches – and buildings, especially huge modern ones.But the matter is not only in the scale. Serra's sculptures are not only abstract compositions that harmoniously add to the space with their spacious scale. They have some mystery, some implicit sense appearing before a pedestrian as an enigma. Their mystique opposes both street furniture and architecture. But first of all it opposes the historical sculpture with its enigma always overshadowed by historical or biographical topic. Krylov's sculpture in the Summer Garden or Minin and Pozharsky's monument on the Red Square do not strike us, because we know that those monuments are erected IN COMMEMORATION of prominent people, as fellow citizens' tribute to their great contribution to the national history. But the crude metal sheets welded at different angles – what are they for? Who needs them?As an art critic, Edward Goldman, said, fame came to Richard Serra in 1989, when the sculpture composition Tilted Arc erected eight years before it was demolished by

  5. Machining of Complex Sculptured Surfaces

    CERN Document Server

    2012-01-01

    The machining of complex sculptured surfaces is a global technological topic in modern manufacturing with relevance in both industrialized and emerging in countries particularly within the moulds and dies sector whose applications include highly technological industries such as the automotive and aircraft industry. Machining of Complex Sculptured Surfaces considers new approaches to the manufacture of moulds and dies within these industries. The traditional technology employed in the manufacture of moulds and dies combined conventional milling and electro-discharge machining (EDM) but this has been replaced with  high-speed milling (HSM) which has been applied in roughing, semi-finishing and finishing of moulds and dies with great success. Machining of Complex Sculptured Surfaces provides recent information on machining of complex sculptured surfaces including modern CAM systems and process planning for three and five axis machining as well as explanations of the advantages of HSM over traditional methods ra...

  6. Eurasia International Sculpture Biennale, Kazakhstan

    OpenAIRE

    Heywood, Anthony

    2017-01-01

    The first Eurasia International Sculpture Biennale was held from 4 July to 4 August 2017 in the atrium of the Palace of Peace and Reconciliation as one of the most important events of the cultural program EXPO-2017, commissioned by the Ministry of Culture and Sports of the Republic of Kazakhstan.

  7. Sculpture: Stone Shapes, Art: 6683.08.

    Science.gov (United States)

    Dubocq, Edward R.

    This elective course for grades 7-12 was created with a three fold purpose: 1) to create in the student an awareness of the effect of sculptural forms on his environment; 2) to introduce the student to an appreciation of stone sculpture; and 3) to further enhance the artistic abilities of the student through sculpting in stone. Course content…

  8. Walter Pater and the Language of Sculpture

    DEFF Research Database (Denmark)

    Østermark-Johansen, Lene

    Walter Pater and the Language of Sculpture is the first monograph to discuss the Victorian critic Walter Pater's attitude to sculpture. It brings together Pater's aesthetic theories with his theories on language and writing, to demonstrate how his ideas of the visual and written language...... the idea of rivalry (paragone) more broadly, examining Pater's concern with positioning himself as an art critic in the late Victorian art world. Situating Pater within centuries of European aesthetic theories as never before done, Walter Pater and the Language of Sculpture throws new light...

  9. HINTS IN OMABE BASED SCULPTURE INSTALLATIONS ...

    African Journals Online (AJOL)

    ASOGWA IFEANYI

    2017-02-02

    Feb 2, 2017 ... to develop both new methods of inquiry and appropriate forms of ... sculpture, music, dance, poetry, movement, dialogue and painting. ... were feared and respected by everybody in the society, including women and children.

  10. EDXRF analysis of sculptures on polychrome wood

    International Nuclear Information System (INIS)

    Felix, Valter de Souza; Calza, Cristiane; Lopes, Ricardo Tadeu; Freitas, Renato P.

    2015-01-01

    In the last years, the analysis of sacred sculptures, belonging to museums, churches and private collectors has gained an increasing interest. This kind of analysis can be extremely valuable to conservation and restoration treatments; it can also supply important information that makes possible to identify an artist, to date a sculpture and to identify forgeries. By means of techniques such as XRF, PIXE or XRD, is possible to identify the composition of materials employed in the manufacturing of the pieces, pigments used in the polychromy and also the presence of ancient or modern retouchings. However, the fact that every artwork is a unique piece emphasizes the necessity of working with non-destructive techniques. This work reports the analysis of two sacred images on polychrome wood - portraying Our Lady (XIX century) and Saint Anthony (XVIII century) - using EDXRF. The analyses were performed with a portable system, consisting of Amptek 123-SDD detector and Mini-X X-Ray tube, with W anode, operating at 30 kV and 40 μA. The analysis of the sculpture of Our Lady revealed the use of the following pigments: lead white, lithopone, vermilion, red ochre, umber and Prussian blue. The analysis of Saint Anthony revealed: lead white, vermilion, brown ochre, bone black and Prussian blue. In both sculptures the use of gold foils for gilding was proved by the presence of Au in the spectra. These results were used to assist the restoration procedures of the sculptures. (author)

  11. EDXRF analysis of sculptures on polychrome wood

    Energy Technology Data Exchange (ETDEWEB)

    Felix, Valter de Souza; Calza, Cristiane; Lopes, Ricardo Tadeu, E-mail: ccalza@lin.ufrj.br, E-mail: ricardo@lin.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil); Freitas, Renato P., E-mail: renato.freitas@ifrj.edu.br, E-mail: valter.felix@ifrj.edu.br [Instituto Federal do Rio de Janeiro (IFRJ), Paracambi, RJ (Brazil)

    2015-07-01

    In the last years, the analysis of sacred sculptures, belonging to museums, churches and private collectors has gained an increasing interest. This kind of analysis can be extremely valuable to conservation and restoration treatments; it can also supply important information that makes possible to identify an artist, to date a sculpture and to identify forgeries. By means of techniques such as XRF, PIXE or XRD, is possible to identify the composition of materials employed in the manufacturing of the pieces, pigments used in the polychromy and also the presence of ancient or modern retouchings. However, the fact that every artwork is a unique piece emphasizes the necessity of working with non-destructive techniques. This work reports the analysis of two sacred images on polychrome wood - portraying Our Lady (XIX century) and Saint Anthony (XVIII century) - using EDXRF. The analyses were performed with a portable system, consisting of Amptek 123-SDD detector and Mini-X X-Ray tube, with W anode, operating at 30 kV and 40 μA. The analysis of the sculpture of Our Lady revealed the use of the following pigments: lead white, lithopone, vermilion, red ochre, umber and Prussian blue. The analysis of Saint Anthony revealed: lead white, vermilion, brown ochre, bone black and Prussian blue. In both sculptures the use of gold foils for gilding was proved by the presence of Au in the spectra. These results were used to assist the restoration procedures of the sculptures. (author)

  12. Walter Pater and the Language of Sculpture

    DEFF Research Database (Denmark)

    Østermark-Johansen, Lene

    are closely linked. Going beyond Pater's views on sculpture as an art form, this study traces the notion of relief (rilievo) and hybrid form in Pater, and his view of the writer as sculptor, a carver in language. Alongside her treatment of rilievo as a pervasive trope, Lene Østermark-Johansen also employs...... the idea of rivalry (paragone) more broadly, examining Pater's concern with positioning himself as an art critic in the late Victorian art world. Situating Pater within centuries of European aesthetic theories as never before done, Walter Pater and the Language of Sculpture throws new light...

  13. American Sculpture and the Library of Congress

    Science.gov (United States)

    Somma, Thomas P.

    2010-01-01

    The Thomas Jefferson Building of the Library of Congress is one of the more significant public structures in American architecture, due for the most part to its wealth and quality of decoration, including an extensive sculptural program executed in 1894-97. The architects entrusted the program to a committee of three prominent sculptors, J. Q. A.…

  14. WOVEN SCULPTURAL PIECE AS ADDED DIMENSION TO ...

    African Journals Online (AJOL)

    user

    2016-06-02

    Jun 2, 2016 ... technologies in textiles as well as the social and economic activities of the people who make ... reality”. It is obvious that the basic principles which apply to all the other arts ... textile work which acts as mixed media sculpture.

  15. Degas's sculptures--three-dimensionality and action.

    Science.gov (United States)

    Rotenberg, Carl T

    2005-01-01

    The psychological self is formed largely by the steady accretion of forms of organizing experience. Outside of the interpersonal realm, these formal and categorical modes of organization can be incorporated through cyclical, continuous, and episodic interaction with modes of cultural expression, such as art, music, and poetry. Degas's sculptures, a highly experimental and personal section of his overall work, have particular formal modes of organization unique to this artist and to his particular era. Formal principles unique to Degas sculpture include the ways he rendered sculpted surfaces, masses in a state of action, and uniquely collaged materials. Degas's sculptures are proto-cinematic because they depict a brief instant in time, as opposed to a more prolonged narrative episode. Empathic, though unconscious, identification with the formal principles of Degas's sculptures shapes in the viewers ordering principles in the self that govern reactions to the vicissitudes of living, object relations, the sense of mortality, and the accomplishment of a sense of agency significant and consequential to the modern era.

  16. Instructional Resources: Issues in Public Sculpture.

    Science.gov (United States)

    Hill, Julie Lasater; And Others

    1988-01-01

    Presents four lesson plans for teaching K-12 students about public sculpture and contemporary sculptors. Highlights the following works: "Playscapes" by Isamu Noguchi, "The Dallas Piece" by Henry Moore, "Old Glory" by Mark di Suvero, and "Face of the Earth" by Vito Acconci. Includes background information on…

  17. Sandscape - engaging people in Met Office science through sand sculpture

    Science.gov (United States)

    Liggins, Felicity; Dowell, Ellen; Wardley, Jamie; Jamieson, Claire

    2017-04-01

    In 2015, the Met Office's award-winning outreach programme, designed to inspire the next generation of scientists and engineers, delivered one of its most ambitious and creative activities to date. It explored how scientists and artists can come together to create an engaging experience for young people and families. This activity was called Sandscape. Sandscape is an interactive sand sculpture workshop exploring how weather and climate affect our health. Budding sand sculptors are shown how to fashion elaborate structures from sand and water - creating a landscape with bridges, skyscrapers, forests and factories. As they work, participants are encouraged by the scientists delivering the activity to reflect on what makes a healthy city, considering how the natural and built environments influence air quality and circulation and how this impacts our health. Topics discussed include urban heat islands, air pollution and dispersion modelling, pollen forecasting and predicting the wind-borne spread of animal diseases. Each hour long workshop culminates in a dramatic demonstration that uses dry ice to represent clean air circulating from mountains, along rivers and into cities. Here we present an overview of Sandscape, identify the strengths and challenges of such a collaborative, innovative and playful approach to public engagement and share the results of our evaluation. Sandscape was originally supported by the Met Office and the Wellcome Trust, and produced by Einstein's Garden in collaboration with the Met Office, scientists from the University of Exeter and sand sculptors from Sand in Your Eye. It was first presented in Einstein's Garden at Green Man festival 2015, an independent music and arts festival held annually in Wales, and has since been invited to run at the 2015 Bournemouth Arts By the Sea Festival and Teignmouth's TRAIL Sculpture Festival in the summer of 2016.

  18. Nathaniel Hitch and the Making of Church Sculpture

    Directory of Open Access Journals (Sweden)

    Claire Jones

    2016-06-01

    Full Text Available Housed at the Henry Moore Institute in Leeds is the archive of the little-known sculptor Nathaniel Hitch (1845–1938. This comprises hundreds of studio photographs, which collectively and individually provide significant insight into a hitherto neglected branch of Victorian sculpture: church sculpture. Changing attitudes to religion from the 1840s onwards created conditions that enabled sculptors such as Hitch to establish successful local and international practices specializing in ecclesiastical work, from ornamental pew ends to free-standing polychrome figurative sculpture. Examining the ecclesiastical dimension of nineteenth-century British sculpture complicates and extends our current understanding of sculpture in the period, by presenting alternative models of education, style, subject matter, sculptural precedents, studio practice, and practices of making to the current centrality of ideal classical sculpture and of the New Sculpture in the scholarship. It allows for the integration of different types of sculptors and sculpture within the study of Victorian sculpture, and prompts investigation into the influence of specifically Christian and British values and concerns on what was still essentially a classical medium.

  19. ' "Life is Movement": Vernon Lee and Sculpture'

    DEFF Research Database (Denmark)

    Østermark-Johansen, Lene

    2018-01-01

    How do living, breathing human bodies respond to the inert bodies of sculpture? This article examines some of the art-theoretical and psychological writings of Violet Paget (‘Vernon Lee’) and Clementina Anstruther-Thomson of the 1880s and 1890s in an attempt to map the evolution of their formalist...... art criticism. Engaging with the eighteenth-century ghosts of Johann Joachim Winckelmann and Gotthold Ephraim Lessing, Lee and Anstruther-Thomson created their very own exploration of art forms evolving in space and in time. Questioning how our reading of literature affects our reading of sculpture...... from Lee’s early essays in Belcaro: Being Essays on Sundry Aesthetical Questions (1881) to the late collaborative volume Art and Man (1924)....

  20. The StorySpinner Sculptural Reader

    OpenAIRE

    Hooper, Clare; Weal, Mark

    2005-01-01

    This demo is of a hypertext reading system called StorySpinner. It follows the sculptural hypertext methodology and has been used as a test bed for experimenting with the authoring of narrative flow in automatically generated stories. Readers are able to select and read one of two available stories. Reading a story involves selecting tarot cards which are mapped to chunks of story text based on possible interpretations of the cards and information concerning current story state.

  1. Review of the research on “structural bionic” method of large sculpture

    Science.gov (United States)

    Yin, Jiang; Yang, Wenchang

    2017-09-01

    This paper presented the basic concept of bionic sculpture and summarized the application status of “structural bionic”theory in large bionic sculpture field. Introduced the development trend and challenges of large bionic sculpture and pointed out that the sculpture's “structural bionic” can bring higher mechanical performance of the new structure and system, The evaluation method and structure design for large bionic sculpture are urgently needed.Finally prospected the market of the large bionic sculpture.

  2. Chrysallis public lighting sculpture, NHS, Oswestry

    OpenAIRE

    Panneels, Inge

    2005-01-01

    “Chrysalis” is an interactive lighting sculpture which pulsates as if breathing. The lighting is especially visible at night, when patients can come and use the nearby public room or wander up and down the corridor. The cocoon shape was informed by workshops with patients and staff at the RJAH in Gobowen, Shropshire. As this is an orthopaedic Hospital, most patients are there for long periods of time recovering from severe life changing injuries. The recurrent theme of ‘circle’; of family, fr...

  3. Shaping space: facial asymmetries in fifth-century Greek sculpture

    NARCIS (Netherlands)

    Hochscheid, H.; Hamel, R.; Wootton, W.; Russell, B.; Libonati, E.

    2015-01-01

    The phenomenon of optical correction in Classical Greek sculpture has been attested by both ancient authors and modern scholars. Despite the apparent normalcy of optical correction in sculpture, however, there are no obvious reasons for it and how such correction worked in statues is a question

  4. ART AND ENGINEERING IN METAL SCULPTURES

    Directory of Open Access Journals (Sweden)

    COSTIN Georgiana Alexandra

    2016-07-01

    Full Text Available This paper shows how engineering and art are combined in making metal sculptures, referring to artistic creations exhibited in the “Dunărea de Jos” University campus in Galați, in the tradition existing between the Faculty of Engineering and the Visual Art Museum of Galați, with a significant contribution of prestigious artists of Galaţi and beyond. In this context, in order to develop the conception and design of some artistic products, many 2D and 3D graphical representation systems of information have appeared in a virtual environment, in which shaping using dedicated software applications, required that these artworks can be described by a series of shaping operation sequences, package design tools Autodesk Inventor CAD being such a solution.

  5. Handedness, Hinduism and sculpture: searching for evidence of lateralisation.

    Science.gov (United States)

    Bhushan, Braj; Rai Sapru, Shikha

    2008-07-01

    The majority of people throughout the world show extreme preference for the right hand. We studied lateral bias depicted in ancient Indian sculptures dating between the 7th and 9th centuries ad. A total of 288 sculptures were selected from various excavation sites/museums and the frequencies were computed on 13 different criteria in order to see the preferential bias for hand depicted in sculptures of male and female figures. The findings are discussed in the light of Hindu mythology and rituals.

  6. 4D Visualization of Painted Sculpture and Murals

    Science.gov (United States)

    Ai, M. Y.; Tong, H.; Shen, L.; Wang, R. X.; Zhang, F.; Zhang, Z. C.; Hu, Q. W.; Zhu, Y. X.; Zhang, H.

    2015-08-01

    Most cultural heritage applications address visualization with using various media or platforms: desktop-based multimedia presentations, museum kiosks, or videos produced with computer animation. However, these techniques can not directly reveal or show the course that the colorful surface of painted sculpture and murals becomes faint along with the change of the climate and time. Most current techniques just preserve the current appearance and disseminate the current situation of the painted sculpture and murals. The course how these forms of cultural heritage change along the time has not been visualized. In this paper we developed an approach to modelling of painted sculpture and murals that has undergone changes over the years. Different hypotheses has also be given if there is uncertainty. A painted sculpture of Mogao Grottoes is used to demonstate this approach.

  7. Microanalysis of pictorial layers in polychrome sculptures

    International Nuclear Information System (INIS)

    Mendoza Cuevas, Ariadna

    2008-01-01

    Cross section samples from polychrome wood sculpture are analyzed by optical microscopy, the nuclear techniques: micro X Ray Fluorescence, micro Proton induced Xray Emission coupled with Rutherford Backscattering and the traditional method by Scanning Electronic Microscopy with Energy Dispersive Xray fluorescence detection (SEMEDX) microanalytical methods. Special emphasis is dedicated to mXRF, a novel advanced technique developed thanks to the last achievements of the Xray optics that can be available by modifying conventional laboratory XRF spectrometer, representing an alternative to the traditional and expensive SEMEDX stratigraphic analysis of pictorial works. The results are compared with respect to spatial resolution to differentiate pictorial layer structure and elemental sensitivity. Number of layer, relative position of layer, layer thickness and chemical composition of pigments are determined in the characterization of valuable polychromes of once church San Juan de Letrán in order to obtain information about their “material history” that should contribute to its provenance and attribution research. The pigments used in this artistic works were identified by their characteristic elements. The elemental distribution maps obtained by the used nuclear techniques precisely reproduced microphotographies obtained by means of Light Microscopy. (author)

  8. Microanalysis of paint layers in polychrome sculptures

    International Nuclear Information System (INIS)

    Mendoza, A.; Falcucci, C.; Jaksic, M.

    2001-01-01

    Cross sections paint layers of polychromes sculpture of the 16 century, located at the City Museum of Havana and currently in the restoration process, have been analyzed by capillary based μXRF , μPIXE , SEM -EDX and light microscopy. Experimental parameters (geometry measurement time) of the capillary based μXRF set up (nominal end diameter equal to 10 μm) were optimized to achieve the resolution required for meaningful scintigraphic studies of the art and archaeological objects, Cumulative x-rays spectra for each layer were obtained in order to perform semi-quantitative analysis. The employed pigments were identified by the characteristics elements and the elemental maps precisely reproduced photographs obtained by means of light microscopy. In the case of nuclear microprobe, RBS for Stoichiometry analysis of paint layers was also performed. additional information on the organic materials was also obtained by chemical analysis. Complementary results obtained by using the analytical techniques are presented and discussed from the point of view of the restoration processes

  9. THE DANCING SCULPTURES OF THE 19TH CENTURY EUROPEAN ART

    Directory of Open Access Journals (Sweden)

    Sibel ALMELEK ISMAN

    2015-04-01

    Full Text Available Dance has been an indispensable element of human life for centuries. Painters and sculptors have created the dynamism of dance steps either on the canvas or stone with the same excitement. Charits, Nymphs, Bacchantes and Satyrs, the Greek and Roman mythological figures who attract attention with their dances have been a source of inspiration for artists. In this research, the dancing sculptures of the 19th century which is an interesting period in European art because of its witnessing of long term styles like Neoclassicism and Romanticism and short term movements such as Realism and Impressionism are examined. Examples of sculptures which brings dance to life before and after the 19th century have also been mentioned. The likenesses as well as dissimilarities in the way the arts of painting and sculpture approach to the theme of dance has been briefly evaluated.

  10. Waiting for Art: The Experience of Real Time in Sculpture

    Directory of Open Access Journals (Sweden)

    Elizabeth Buhe

    2011-05-01

    Full Text Available Why and how does some contemporary art make us wait, and why does the beholder choose to stay? This study seeks to answer this question by exploring what happens to the viewer while waiting in front of a “time sculpture,” a term coined here to mean a three-dimensional artwork that is dynamic over a set period of time. Through an analysis of select works by artists Anish Kapoor, Amelia Whitelaw, Michael Sailstorfer, and Roman Signer, the article posits that while in front of these time sculptures, the viewer experiences an anxiety of waiting and temporal confusion that glues him to the spot. Ultimately, by drawing upon Henri Bergson’s concept of duration, the essay suggests that the viewership of time sculpture allows for a heightened state of perception. Normal 0 false false false EN-US X-NONE X-NONE

  11. Inspection of a Medieval Wood Sculpture Using Computer Tomography

    Science.gov (United States)

    Kapitany, K.; Somogyi, A.; Barsi, A.

    2016-06-01

    Computer tomography (CT) is an excellent technique for obtaining accurate 3D information about the human body. It allows to visualize the organs, bones and blood vessels, furthermore it enables to diagnose anomalies and diseases. Its spatial reconstruction capability supports other interesting applications, such as inspecting different, even valuable objects like ancient sculptures. Current paper presents a methodology of evaluating CT and video imagery through the example of investigating a wood Madonna with infant Jesus sculpture from the 14th century. The developed techniques extract the outer boundary of the statue, which has been triangulated to derive the surface model. The interior of the sculpture has also been revealed: the iron bolts and rivets as well as the woodworm holes can be mapped. By merging the interior and outer data (geometry and texture) interesting visualizations (perspective views, sections etc.) have been created.

  12. INSPECTION OF A MEDIEVAL WOOD SCULPTURE USING COMPUTER TOMOGRAPHY

    Directory of Open Access Journals (Sweden)

    K. Kapitany

    2016-06-01

    Full Text Available Computer tomography (CT is an excellent technique for obtaining accurate 3D information about the human body. It allows to visualize the organs, bones and blood vessels, furthermore it enables to diagnose anomalies and diseases. Its spatial reconstruction capability supports other interesting applications, such as inspecting different, even valuable objects like ancient sculptures. Current paper presents a methodology of evaluating CT and video imagery through the example of investigating a wood Madonna with infant Jesus sculpture from the 14th century. The developed techniques extract the outer boundary of the statue, which has been triangulated to derive the surface model. The interior of the sculpture has also been revealed: the iron bolts and rivets as well as the woodworm holes can be mapped. By merging the interior and outer data (geometry and texture interesting visualizations (perspective views, sections etc. have been created.

  13. Sculpture africaine. Blessures et altérité

    Directory of Open Access Journals (Sweden)

    Gaetano Speranza

    2009-03-01

    Full Text Available Au delà de la notion de “blessure” relative à l’objet, l’auteur s’attache aux traumatismes culturels résultant de la rencontre entre la sculpture africaine et le monde occidental. Un exemple particulier est celui des instruments de musique ethnographiques, dont la restauration est souvent tributaire des conceptions occidentales.Beyond the notion of « injury » for the object, the author dwells on cultural traumatisms resulting from the meeting between African sculpture and the western world. A particular example is the one of ethnographical musical instruments for which restoration is often tributary of western conceptions.

  14. Effects of Photography on Acquisition of Sculpture Skills among ...

    African Journals Online (AJOL)

    The study investigated the effects of photography on acquisition of sculpture skills among Junior Secondary School Students in Osun State. Forty students were randomly selected from two schools. The two schools were purposefully selected from fifty secondary schools in Ife Central Local Government Council Area of Osun ...

  15. Effects of Photography on Acquisition of Sculpture Skills among ...

    African Journals Online (AJOL)

    FIRST LADY

    Abstract. The study investigated the effects of photography on acquisition of sculpture skills among Junior Secondary School Students in Osun State. Forty students were randomly selected from two schools. The two schools were purposefully selected from fifty secondary schools in Ife Central Local. Government Council ...

  16. 37 CFR 202.10 - Pictorial, graphic, and sculptural works.

    Science.gov (United States)

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Pictorial, graphic, and... Pictorial, graphic, and sculptural works. (a) In order to be acceptable as a pictorial, graphic, or... utility or design patent will not affect the registrability of a claim in an original work of pictorial...

  17. Afterword: Victorian Sculpture for the Twenty-First Century

    Directory of Open Access Journals (Sweden)

    David J. Getsy

    2016-06-01

    Full Text Available Commenting on the directions proposed by this issue of '19', the afterword discusses the broad trends in twenty-first century studies of Victorian sculpture and the opportunity for debate arising from the first attempt at a comprehensive exhibition.

  18. The Golden Beauty: Brain Response to Classical and Renaissance Sculptures

    Science.gov (United States)

    Di Dio, Cinzia; Macaluso, Emiliano; Rizzolatti, Giacomo

    2007-01-01

    Is there an objective, biological basis for the experience of beauty in art? Or is aesthetic experience entirely subjective? Using fMRI technique, we addressed this question by presenting viewers, naïve to art criticism, with images of masterpieces of Classical and Renaissance sculpture. Employing proportion as the independent variable, we produced two sets of stimuli: one composed of images of original sculptures; the other of a modified version of the same images. The stimuli were presented in three conditions: observation, aesthetic judgment, and proportion judgment. In the observation condition, the viewers were required to observe the images with the same mind-set as if they were in a museum. In the other two conditions they were required to give an aesthetic or proportion judgment on the same images. Two types of analyses were carried out: one which contrasted brain response to the canonical and the modified sculptures, and one which contrasted beautiful vs. ugly sculptures as judged by each volunteer. The most striking result was that the observation of original sculptures, relative to the modified ones, produced activation of the right insula as well as of some lateral and medial cortical areas (lateral occipital gyrus, precuneus and prefrontal areas). The activation of the insula was particularly strong during the observation condition. Most interestingly, when volunteers were required to give an overt aesthetic judgment, the images judged as beautiful selectively activated the right amygdala, relative to those judged as ugly. We conclude that, in observers naïve to art criticism, the sense of beauty is mediated by two non-mutually exclusive processes: one based on a joint activation of sets of cortical neurons, triggered by parameters intrinsic to the stimuli, and the insula (objective beauty); the other based on the activation of the amygdala, driven by one's own emotional experiences (subjective beauty). PMID:18030335

  19. Analysis of sculptures using XRF and X-ray radiography

    Science.gov (United States)

    Calza, C.; Oliveira, D. F.; Freitas, R. P.; Rocha, H. S.; Nascimento, J. R.; Lopes, R. T.

    2015-11-01

    This work reports the analysis of two sacred images on polychrome wood using X-ray Radiography and Energy Dispersive X-Ray Fluorescence. The first case is the analysis of a sculpture portraying Saint Sebastian, the patron saint of Rio de Janeiro, which is considered the second most ancient sacred image of Brazil. This sculpture was made in Portugal and was transported to Brazil by Estácio Sá, founder of the city of Rio de Janeiro, in 1565. Nowadays, it is located on the main altar of the Church of Capuchin Friars. The second case is the analysis of a sculpture representing Our Lady of Conception, which is located in the D. João VI Museum (EBA/UFRJ, Rio de Janeiro). The objective of these analyses was to evaluate the general conditions of the sculptures, identifying possible problems and internal damages, areas that revealed signs of previous retouchings and the materials and pigments employed by the artists, in order to assist its restoration procedures. EDXRF measurements were carried out with a portable system, developed at the Nuclear Instrumentation Laboratory, consisting of a Si-PIN XR-100CR detector from Amptek and an Oxford TF3005 X-ray tube with W anode. An X-ray source, a CR System GE CR50P and IP detectors were used to perform the radiographs. The XRF analysis of the sculptures identified the original pigments in both cases and the radiographic images revealed details of the manufacture; restored regions; extensive use of lead white; presence of cracks on the wood; use of nails and spikes, etc.

  20. The golden beauty: brain response to classical and renaissance sculptures.

    Directory of Open Access Journals (Sweden)

    Cinzia Di Dio

    Full Text Available Is there an objective, biological basis for the experience of beauty in art? Or is aesthetic experience entirely subjective? Using fMRI technique, we addressed this question by presenting viewers, naïve to art criticism, with images of masterpieces of Classical and Renaissance sculpture. Employing proportion as the independent variable, we produced two sets of stimuli: one composed of images of original sculptures; the other of a modified version of the same images. The stimuli were presented in three conditions: observation, aesthetic judgment, and proportion judgment. In the observation condition, the viewers were required to observe the images with the same mind-set as if they were in a museum. In the other two conditions they were required to give an aesthetic or proportion judgment on the same images. Two types of analyses were carried out: one which contrasted brain response to the canonical and the modified sculptures, and one which contrasted beautiful vs. ugly sculptures as judged by each volunteer. The most striking result was that the observation of original sculptures, relative to the modified ones, produced activation of the right insula as well as of some lateral and medial cortical areas (lateral occipital gyrus, precuneus and prefrontal areas. The activation of the insula was particularly strong during the observation condition. Most interestingly, when volunteers were required to give an overt aesthetic judgment, the images judged as beautiful selectively activated the right amygdala, relative to those judged as ugly. We conclude that, in observers naïve to art criticism, the sense of beauty is mediated by two non-mutually exclusive processes: one based on a joint activation of sets of cortical neurons, triggered by parameters intrinsic to the stimuli, and the insula (objective beauty; the other based on the activation of the amygdala, driven by one's own emotional experiences (subjective beauty.

  1. a Target Aware Texture Mapping for Sculpture Heritage Modeling

    Science.gov (United States)

    Yang, C.; Zhang, F.; Huang, X.; Li, D.; Zhu, Y.

    2017-08-01

    In this paper, we proposed a target aware image to model registration method using silhouette as the matching clues. The target sculpture object in natural environment can be automatically detected from image with complex background with assistant of 3D geometric data. Then the silhouette can be automatically extracted and applied in image to model matching. Due to the user don't need to deliberately draw target area, the time consumption for precisely image to model matching operation can be greatly reduced. To enhance the function of this method, we also improved the silhouette matching algorithm to support conditional silhouette matching. Two experiments using a stone lion sculpture of Ming Dynasty and a potable relic in museum are given to evaluate the method we proposed. The method we proposed in this paper is extended and developed into a mature software applied in many culture heritage documentation projects.

  2. Looking for Colour on Greek and Roman Sculpture

    OpenAIRE

    Amanda Claridge

    2011-01-01

    Review of: Vinzenz Brinkmann, Oliver Primavesi, Max Hollein, (eds), Circumlitio. The Polychromy of Antique and Medieval Sculpture. Liebighaus Skulpturensammlung, Frankfurt am Main, 2010. New scientific methods now being applied to the analysis of traces of pigments and gilding on ancient Greek and Roman marble statuary, and other marble artefacts, have the potential to revolutionise our understanding of the relationship between form and colour in antiquity. At present the enquiry is still...

  3. Rock Engravings and Sculptures of North Guwahati, Assam

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    Dwipen Bezbaruah

    2016-02-01

    Full Text Available Evidences of rock engravings and sculptures, in Assam, are predominantly found to occur in the vicinity of the temples. Incidence of images of Gods and Goddesses, faunal and floral motif are invariably more. Apart from these, some geometric designs are also perceived. Such tangible archaeological heritages are considered important evidences for understanding the past in a more meaningful way. Therefore, it is pertinent to systematically document these sites and the remains before natural and anthropogenic obliteration. The objective of the present paper is to record and document the rock engravings and sculptures observed in the archaeological sites, namely Dirgheswari, Aswakranta, Manikarneswar, Rudreswar and Kanai Boroshi bowa of North Guwahati in Kamrup district, Assam, which are protected and preserved by the Directorate of Archaeology, Assam and to understand the archaeological context of the sites and their remains. The data for the present paper have been collected through field visit and Exploration was conducted in dry and winter season. The findings of the present work comprises of some sculptures of Ganesa, Yama, Sage, Kali, deities, bull without head, human figures, broken piece of a tiger, remains of door frame or pillar and shrines. Series of dot marks, cut marks, inscription, image of Shiva, foot impression, chess board, square, bow, signs, female figurine, and elephant engravings constitute the rock engravings observed in the area.

  4. Introduction to British Sculpture Abroad in the 1960s

    Directory of Open Access Journals (Sweden)

    Jon Wood

    2016-07-01

    Full Text Available In the 1960s, British sculpture enjoyed a complex transitional life, taking on a new, bold, and increasingly internationalized profile, at the very same time that its forms and meanings were being challenged and contested. Both in Britain and beyond its shores, sculpture experienced substantial reorientation at the same time as it developed a rich and complicated “import” and “export” life, conceptually, commercially, and curatorially. When “Sculpture” was “British” and “Abroad”, its “abroad-ness” was not always so explicitly visible, since its forms and concerns frequently chimed with sensibilities and approaches that were emerging elsewhere too, whether they were figurative or abstract, Constructivist or Pop. At the same time, when sculpture was being displayed in Britain, whether in terms of groups, schools, and/or recent tendencies, it was increasingly described as “British Sculpture”. Visual evidence of foreign impact and exchange gradually emerged at the same time as this national and generational trope became a cultural identifier on a broader cultural landscape.

  5. External-beam PIXE analysis of small sculptures

    International Nuclear Information System (INIS)

    Gyodi, I.; Demeter, I.; Hollos-Nagy, K.; Kovacs, I.; Szokefalvi-Nagy, Z.

    1999-01-01

    Non-destructive analysis of precious art objects is an important tool to solve provenance problems or to facilitate restoration. External beam PIXE analysis is one of the most powerful and popular methods used in this respect. The paper summarises the external beam PIXE set-up at the Accelerator Laboratory in Budapest, and two selected applications are described. Different parts of a small Cambodian metal sculpture probably made in the 11th century were analysed. It was observed that the sculpture was composed of an iron core and an outer bronze shell. This sculptural technique was well known in the Middle-East but no indication has been found about its use in the Far-East, yet. Before its restoration paint traces on a wooden relief of St. Jerome made by an unknown artist in about 1600 were analysed. Different white and red paints were distinguished at selected points and the presence of titanium on a certain part of the relief was attributed to a repainting in modern times

  6. IMPACT EFECTS OF TWO LANGUAGES: PLASTIC (SCULPTURAL AND CINEMATOGRAPHIC

    Directory of Open Access Journals (Sweden)

    OLĂRESCU DUMITRU

    2016-12-01

    Full Text Available It is known that art and culture constitute the expression of the spiritual civilization of a nation and that the Man – the creator of beauty – is in its centre. Art is a diff erent way of presenting the essence of the world or how it was expressed by Lucian Blaga, it is a pulling out from the immediate and a permanent transposition into the immediate, as a present eternal horizon. All these ideas have always drawn the attention of fi lmmakers, establishing themselves as complex topics for various cinematographic investigations and occupying a space in the evolution of nonfi ction fi lms about art, starting with the European fi lmmakers of the 20s of the last century up to the present, in the era of the image. We’re interested in the conditions and aesthetic implications of the process of assimilation of the art languages of plastic arts, especially that of sculpture by the cinematic language. We refer to the artwork of the famous sculptor Constantin Brancusi, who would have turned one hundred and forty years in 2016. If the sculpture is static, static par excellence, centrifugal, the fi lm belongs to the fi eld of centripetal movements that can be performed and followed through by the camera in its own motion. Th e centring of the image permits to select and emphasize the important aspects of the work and determines the distance from which they are viewed, establishing the contents and the delimitation of the fi eld of vision. Thus, the language of cinema gives us the possibility to study the same sculpture from diff erent aspects: general plan, environmental plan, foreground plan, detailed shot. In a movie dedicated to sculpture the expressiveness of the image depends on the angle of shooting, lighting, and of course, on editing. The famous opera of Brancusi „Th e Endless Column” (the full-length fi lm „Sculptor”, directed by Cornel Mihalache gets new dimensions owing to the high shot angle on the background of a cloudy sky and a

  7. Looking for Colour on Greek and Roman Sculpture

    Directory of Open Access Journals (Sweden)

    Amanda Claridge

    2011-12-01

    Full Text Available Review of: Vinzenz Brinkmann, Oliver Primavesi, Max Hollein, (eds, Circumlitio. The Polychromy of Antique and Medieval Sculpture. Liebighaus Skulpturensammlung, Frankfurt am Main, 2010. New scientific methods now being applied to the analysis of traces of pigments and gilding on ancient Greek and Roman marble statuary, and other marble artefacts, have the potential to revolutionise our understanding of the relationship between form and colour in antiquity. At present the enquiry is still in its infancy, but the papers delivered at a conference held in Frankfurt in 2008, reviewed here, provide a general introduction to the subject and to a wide range of work in progress.

  8. Ultrastructure of pollen grain sculpturing in several species of the Rosaceae family

    Directory of Open Access Journals (Sweden)

    Józef Kocoń

    2014-01-01

    Full Text Available The sculpturing patterns of pollen grains in some species of the Rosaceae family were analyzed by SEM. Three patterns are described, typical for Prunus spinosa, Pyrus elengrifolia and Crataegus sp. The role of SEM analysis of sculpturing patterns in taxonomy can be compared to the "finger print" method in chemical plant taxonomy.

  9. Socio-Psychological Impact of Outdoor Sculptures in Nigeria Urban Cities

    Directory of Open Access Journals (Sweden)

    Allan Francis Ebunola Oladugbagbe

    2016-06-01

    Full Text Available One major element that finds expression at road intersections, parks, gardens, square and open spaces in the urban landscape are outdoor sculptures. Of great significance is the historical information they disseminate, the visual impressions they convey and the aesthetic value they add to the quality of the city. From 1960s and after the civil war, the uses of sculptures for embellishments in public places have increased tremendously in Nigeria. However, outdoor sculpture for the purpose of recreation and relaxation in our built environment has not been adequately addressed scholastically in Nigeria. This paper, therefore, focuses on the social values derivable from the use of sculpture in urban design and the losses that could accrue to the social system if not adequately managed. The values of these sculptures to the socio-psychological development of Nigerians and the beautification of the urban environment are equally emphasized. The study shows that incorporating sculptures into public places without doubt will heighten public appreciation and aesthetic perception and make Nigerian cities unique and vibrant.Keywords: Nigeria urban cities; socio-psychological impact; outdoor sculptures.

  10. Dementia and sculpture-making: Exploring artistic responses of people with dementia.

    Science.gov (United States)

    Chauhan, Sumita

    2018-01-01

    In its form, sculpture reveals not only the artist's self-expression but also the transformative qualities through which it influences our senses. Frequent interactions with sculpture can provide creative awareness, which in turn leads to a better understanding and appreciation of artistic expressions. This paper examines possible ways in which the creative potential of people with dementia can be explored through meaningful artistic engagement with sculpture-making processes. A study was conducted involving seven participants diagnosed with the early stages of dementia who engaged and experimented with different types of sculpture-making processes, from clay and papier mâché to virtual and digital sculptures. In the collective and collaborative environment of the group sessions, the creative responses of the participants to each process were unique. Each sculpture created by the participants enfolded their self-initiated ideas and stories reflecting the conscious expressions of their presence in a particular time and space. This paper argues that while cognitive impairment may affect the behavioural, visual and perceptual abilities of people with dementia, there is ample evidence to suggest that the viewing and making sculpture may influence the sensory involvement and consequently the imagination and creativity of people with early stage dementia.

  11. Applications of petrography and electron microprobe analysis to the study of Indian stone sculpture

    International Nuclear Information System (INIS)

    Newman, R.

    1992-01-01

    Examples of research on ancient Indian stone artefacts utilizing petrographic examination coupled with qualitative and quantitative electron beam microprobe analysis of specific minerals are described. Types of artefacts discussed include Gandharan schist sculptures, Pala dynasty phyllite and schist objects from eastern India. Hoysala sculptures from Karnataka state (southern India), and sandstone objects from northern India. In spite of the rich history of stone sculpture in the Indian subcontinent, characterization studies to date have been limited in scope, typically involving unprovenanced artefacts. The examples described point to areas in which more extensive research could produce useful information for the provenancing of artefacts. (author)

  12. Ice Sheets & Ice Cores

    DEFF Research Database (Denmark)

    Mikkelsen, Troels Bøgeholm

    Since the discovery of the Ice Ages it has been evident that Earth’s climate is liable to undergo dramatic changes. The previous climatic period known as the Last Glacial saw large oscillations in the extent of ice sheets covering the Northern hemisphere. Understanding these oscillations known....... The first part concerns time series analysis of ice core data obtained from the Greenland Ice Sheet. We analyze parts of the time series where DO-events occur using the so-called transfer operator and compare the results with time series from a simple model capable of switching by either undergoing...

  13. PIXE analysis of museum soapstone sculptures from Esie, south west Nigeria

    International Nuclear Information System (INIS)

    Olabanji, S.O.; Olarewaju, V.O.; Onabajo, O.

    1989-05-01

    The PIXE technique was employed for the study of Esie museum stone sculptures using 2.55 MeV protons from the 3 MeV tandem accelerator (NEC 3 UDH) in Lund, coupled with the geological and archaeological findings. The aim is to elucidate and decipher the prodigious but rather enigmatic and bewildering stone sculptures. PIXE results show that the composition of the stone sculptures are 40.69% talc-tremolite schist, 30.88% talc-chlorite schist, 15.20% talc-tremolite-anthophyllite schist and 13.24% talc-amphibolite schist. Thus the composition of Esie sculptures are found to be the same with the locally available talc-schists present around Esie. The geological evidence (mineralogical results) corroborated this as there was no textural or mineralogical difference between the talc-bearing country rock (outcrop) in Esie and the museum soapstone samples studied. Consequently, there is a very high probability that the sculptures were carved using the locally available talc-schists. (author). 7 refs, 4 figs, 2 tabs

  14. Henry Moore’s Public Sculpture in the US: The Collaborations with I. M. Pei

    Directory of Open Access Journals (Sweden)

    Alex Potts

    2016-07-01

    Full Text Available The many commissions Henry Moore received for public sculpture in the United States provided the occasion for several quite distinctive works. While not site specific, these were unique, and their final form, scale, and disposition was elaborated with a particular setting in mind. This aspect of Moore’s work in the US, which began with the monumental piece he designed for the Lincoln Center in New York in 1963–65, is examined here by focusing on the productive relationship he forged with the architect I. M. Pei in the 1970s. The sculptures Moore produced in collaboration with Pei respond in suggestive ways to the spatial environments created in American cities by late modern architectural developments. They also realize an oddly effective combination of the biomorphic and abstract that differs both from the bodily conception of Moore’s earlier work and the non-figurative character of much public sculpture of the time.

  15. Effects of sculpture based art therapy in dementia patients-A pilot study.

    Science.gov (United States)

    Seifert, Kathrin; Spottke, Annika; Fliessbach, Klaus

    2017-11-01

    Art and art therapy open up interesting possibilities for dementia patients. However, it has not been evaluated scientifically so far, whether the art of sculpting has any benefits. In this non-randomized pilot study with twelve participants, we investigated the feasibility and acceptance of sculptural activity in patients with dementia and the effects on their well-being. A questionnaire was custom-designed to investigate five key aspects of well-being: mental state and concentration, corporeal memory, self-reliance, self-esteem and physicality. Remarkable improvements were seen in several subscales in the sculptural activity group, but not the control group: Mental state and concentration (nine of thirteen key aspects), self-reliance (four of five), self-esteem (one of one) and physicality (two of two). The results of this pilot study indicate the multidimensional effects of sculptural activity on patients living with dementia. The field would benefit greatly from further research.

  16. Ice, Ice, Baby!

    Science.gov (United States)

    Hamilton, C.

    2008-12-01

    The Center for Remote Sensing of Ice Sheets (CReSIS) has developed an outreach program based on hands-on activities called "Ice, Ice, Baby". These lessons are designed to teach the science principles of displacement, forces of motion, density, and states of matter. These properties are easily taught through the interesting topics of glaciers, icebergs, and sea level rise in K-8 classrooms. The activities are fun, engaging, and simple enough to be used at science fairs and family science nights. Students who have participated in "Ice, Ice, Baby" have successfully taught these to adults and students at informal events. The lessons are based on education standards which are available on our website www.cresis.ku.edu. This presentation will provide information on the activities, survey results from teachers who have used the material, and other suggested material that can be used before and after the activities.

  17. Acid rain attack on outdoor sculpture in perspective

    Science.gov (United States)

    Livingston, Richard A.

    2016-12-01

    A major concern motivating research in acid rain materials effects has been the potential for damage to cultural heritage, particularly outdoor marble and bronze sculpture. However, a combination of field and laboratory studies has failed to show a correlation between rain pH and loss of materials. In order to understand this counterintuitive lack of acid rain effect, an aqueous geochemical modeling approach was used to analyze rain runoff chemistry for the relative importance of acid rain neutralization, dry deposition, and in the case of marble, natural carbonate dissolution. This approach involved the development of pH - SO42- phase diagrams for marble (calcium carbonate) and bronze (copper) under ambient environmental conditions. This then enabled reaction path modeling of the acid neutralization process using the pH range typically found in wet deposition (3.5-6). The results were for marble that the theoretical maximum amount of Ca2+ ion that could be lost due acid rain neutralization would be 0.158 mmol/l compared to 10.5 mmol/l by dry deposition, and for bronze, the Cu2+ ion losses would be 0.21 mmol/l and 47.3 mmol/l respectively. Consequently dry deposition effects on these materials have the potential to dominate over wet deposition effects. To test these predictions the geochemical models were applied to examples of data sets from mass balance (runoff vs rainfall) studies on a marble statue in New York City and some bronze memorial plaques at Gettysburg PA. Although these data sets were collected in the early 1980s they remain valid for demonstrating the mass balance method. For the marble statue, the mean Ca2+ losses by dry deposition was about 69% of the total compared 0.3% for acid rain neutralization, which was less than the natural carbonate dissolution losses of 0.8%. For the bronze, the mean Cu2+ losses were 70.6% by SO42- dry deposition and 23% by NO3- dry deposition compared to 6.4% by acid rain neutralization. Thus for both cases the wet

  18. Examinations of wooden sculptures from the altar of Veit Stoss in Cracow

    International Nuclear Information System (INIS)

    Braziewicz, J.; Dudzik, R.; JaskoIa, M.; Kubala-Kukus, A.; Kretschmer, W.; Rutkowski, J.; Semaniak, J.; Scharf, A.; Stankiewicz, M.; Uhl, T.

    2005-01-01

    The AMS facility at Erlangen University was used for dating samples from a wooden coping of the Veit Stoss's altar, one taken from its component originating from the 15th century and another one taken from its newer renovated part. The XRF method has been used to investigate trace element distribution inwards the sculptures. Concentrations of some elements, including Cl and Pb, show systematic increase while approaching the front or back side of the sculptures. The measured distributions are discussed in the context of history of the altar, in particular renovation and restoration procedures it underwent over the years

  19. Politics of Participation in Benoît Maubrey’s Speaker Sculptures

    DEFF Research Database (Denmark)

    Keylin, Vadim

    a designated number, or using Bluetooth or WiFi technologies, and express themselves freely through the sculpture. In my paper, I investigate the strategies of audience engagement the Maubrey employs and their applicability to the acoustic design of urban spaces. Through their numerous loudspeakers, Speaker...

  20. Three-Dimensional Interpretation of Sculptural Heritage with Digital and Tangible 3D Printed Replicas

    Science.gov (United States)

    Saorin, José Luis; Carbonell-Carrera, Carlos; Cantero, Jorge de la Torre; Meier, Cecile; Aleman, Drago Diaz

    2017-01-01

    Spatial interpretation features as a skill to acquire in the educational curricula. The visualization and interpretation of three-dimensional objects in tactile devices and the possibility of digital manufacturing with 3D printers, offers an opportunity to include replicas of sculptures in teaching and, thus, facilitate the 3D interpretation of…

  1. Chronologies in wood and resin: AMS 14C dating of pre-Hispanic Caribbean Wood Sculpture

    Science.gov (United States)

    Joanna Ostapkowicz; Christopher Bronk-Ramsey; Fiona Brock; Tom Higham; Alex C. Wiedenhoeft; Erika Ribechini; Jeannette J. Lucejko; Samuel. Wilson

    2012-01-01

    This paper establishes a chronological framework for selected pieces of Caribbean (Tafno/Lucayan) wooden sculpture, enabling previously ahistoric artefacts to fit back into the wider corpus of pre-colonial material culture. Seventy-two 14C AMS determinations from 56 artefacts held in museum collections are reported, including 32 ceremonial

  2. Nature and sculpture in the creation of African theatre scenery | Iwuh ...

    African Journals Online (AJOL)

    The meaning of space is defined by the images contained in that space. Creating scenery for the theatre as an indoor activity involves either the creation of imaginary forms or the replication of existing images around the creator's environment. These imported items include natural vegetation, architecture, sculpture and ...

  3. Dress Fashion in Feminist and Child Rights Campaigns in Ghanaian Public Sculptures of the 1990s

    Science.gov (United States)

    Essel, Osuanyi Quaicoo; Opoku-Mensah, Isaac

    2017-01-01

    This article examines how dress fashion in outdoor sculptures of the 1990s in the Accra cityscape accentuated feminist activism, sensitised child right campaigns, and encouraged girl-child education in support of governmental efforts and activism of civil society organisations in Ghana. It gives attention to how dress fashion of the time was used…

  4. Study of Italian Renaissance sculptures using an external beam nuclear microprobe

    Science.gov (United States)

    Zucchiatti, A.; Bouquillon, A.; Moignard, B.; Salomon, J.; Gaborit, J. R.

    2000-03-01

    The use of an extracted proton micro-beam for the PIXE analysis of glazes is discussed in the context of the growing interest in the creation of an analytical database on Italian Renaissance glazed terracotta sculptures. Some results concerning the frieze of an altarpiece of the Louvre museum, featuring white angels and cherubs heads, are presented.

  5. Study of Italian Renaissance sculptures using an external beam nuclear microprobe

    International Nuclear Information System (INIS)

    Zucchiatti, A.; Bouquillon, A.; Moignard, B.; Salomon, J.; Gaborit, J.R.

    2000-01-01

    The use of an extracted proton micro-beam for the PIXE analysis of glazes is discussed in the context of the growing interest in the creation of an analytical database on Italian Renaissance glazed terracotta sculptures. Some results concerning the frieze of an altarpiece of the Louvre museum, featuring white angels and cherubs heads, are presented

  6. Allergic contact dermatitis from sculptured acrylic nails: special presentation with an airborne pattern

    Science.gov (United States)

    Maio, Paula; Carvalho, Rodrigo; Amaro, Cristina; Santos, Raquel; Cardoso, Jorge

    2012-01-01

    Methylmethacrylate was first reported in 1941 as a cause of contact dermatitis. Since then, occupational contact allergies to acrylates in dentistry, orthopedic surgery, printing industry and industry have been reported, but few reports are found in the literature as a consequence of the contact with sculptured artificial acrylic nails which are increasingly popular. We describe here 3 patients with contact allergy to acrylates in artificial sculptured nails. Patch tests were performed with the Portuguese baseline series of contact allergens and an extended series of acrylates were applied. In particular, we tested three female patients with allergic contact dermatitis from sculptured acrylic nails. Two of these patients were both customers and also technical nail beauticians. Two patients developed periungual eczema; one presented only with face and eyelid dermatitis had no other lesions. The tests showed positive reaction to 2-hydroxyethylmethacrylate (2-HEMA) and 2-hydroxypropylmethacrylate (2-HPMA) in all the three patients. Our cases demonstrate the variety of clinical presentations of allergic contact dermatitis from acrylic sculptured nails. They show the need to warn patients of persistent and sometimes permanent side effects of these products. They also emphasize the importance of cosmetic ingredient labeling. PMID:25386316

  7. The Open Space Sculptures Used in the Gençlik Park towards Visual Perception of Park Users

    Directory of Open Access Journals (Sweden)

    Ahmet Polat

    2012-11-01

    Full Text Available Urban parks are the most important areas that allow recreational activities in our towns. Increasing the visual quality of urban parks provides positive impacts on urban quality. Besides the artistic and technical features of open space sculptures which are used for urban park designs are the visual perceptions and preferences of park users are also important. In the context of this study, six sculptures in Gençlik Park which is in the boundaries Ankara have been considered. The aim of the study, to measure the visual quality of the sculptures in the urban parks through park users and to reveal the relationship between visual landscape indicators (of being interesting, coherence, complexity, meaningfulness, and mystery and the visual quality. For this purpose, the six pieces in Ankara Youth Park of sculpture were evaluated the scope of research. According to the results of the study; it was realized that park users like sculptures visually. A statistically significant relationship was found between the visual quality of the sculptures and some landscape indicators (to be interesting, mystery and harmony. In addition to these, some suggestions were made regarding the use of sculptures in urban parks.

  8. Vessel guardians: sculpture and graphics related to the ceramics of NorthEastern European hunter-gatherers

    Directory of Open Access Journals (Sweden)

    Ekaterina Aleksandrovna Kashina

    2015-12-01

    Full Text Available North-Eastern European hunter-gatherer ceramic sculptures, relief sculptures and graphic images on vessels are discussed. Five groups of finds are distinguished according to their chronology (4000–2500 BC cal and represented subject (birds, human head, human figure, mammal head etc.. Their production believes to be a female craft, their making had ritual aims and their emerging was independent from any influences of pastoral/agricultural societies.

  9. The history of the "Virgin with Child" sculpture (Ottaviano, Naples, southern Italy)

    DEFF Research Database (Denmark)

    Balassone, Giuseppina; Toscano, Maria; Cavazzini, Giancarlo

    2014-01-01

    A life-size whitish marble statue of a "Virgin with Child" has been recently rediscovered in the St.Rosario church located in Ottaviano, a small town near Naples (southern Italy). This artwork shows stylistic features of the Tuscan-Roman school of the 16th century, and is framed in an intriguing...... historical context. Historical documents testify that the sculpture was a property of the cadet branch of noble Tuscan family of the Medici, the Medici of Ottaviano. A multianalytical approach has been used to try to indicate the supply area of the white marble of the studied sculpture. Considering the whole...... mineralogical, petrographic and geochemical data, the source rock can be possibly limited to the main classical white marbles of the Mediterranean district, as the classical marble of Aphrodisias. A reuse practice of a former artwork can be also hypothesized....

  10. IMPLEMENTING TQM IN RURAL MONUMENTAL BAROQUE SCULPTURE IN THE BANAT AREA

    Directory of Open Access Journals (Sweden)

    I. PETROMAN

    2008-05-01

    Full Text Available The cultural patrimony preserves the memory and identity of the Banat’s rural area, defining the personality specific to each locality depending on the colonizing ethnic group after the liberation from the Turkish yoke. Steadily degrading, this baroque sculptural patrimony must be saved and integrated into a tourist circuit through the development of a managerial strategy and the implementation of a total quality management that cover the widest area possible of issues related to the intact preservation of monuments and to their conservation. The valorisation of monumental baroque sculpture in the rural area must be done together with the development of a managerial strategy of sustainable development thus contributing to the making up of an emblematic image specific to the Banat village and to the inclusion into regional, national, and international tourist circuits through such modern forms of tourism as cultural tourism, rural tourism, heritage tourism, interethnic tourism, religious tourism, and business tourism.

  11. High Rise Building: The Mega Sculpture Made Of Steel, Concrete and Glass

    Science.gov (United States)

    Stefańska, Alicja; Załuski, Daniel

    2017-10-01

    High rise building has transformed from providing not only the expansion of floor space but functioning as mega sculpture in the city. The shift away from economic efficiency driven need is only expected to grow in the future. Based on literature studies; after analysing planning documents and case studies, it was examined whether the presumption that gaining the maximum amount of usable area is the only driving factor; or if the need for the creation of an image for the city provided a supplementary reason. The results showed that forming high rise buildings as three-dimensional sculptures is influenced not only by aesthetics, but also marketing. Visual distinction in the city skyline is economically beneficial for investors gaining not only functionality but art, enriching the cultural landscape. Organizing architectural competitions, public debates and following the latest art trends is therefore possible due to large budgets of such projects.

  12. Local Treatment for Monochrome Outdoor Painted Metal Sculptures: Assessing the suitability of conservation paints for retouching

    OpenAIRE

    van Basten, Nikki; Defeyt, Catherine; Rivenc, Rachel

    2015-01-01

    When outdoor painted sculptures get chipped, scratched or abraded, conservators might consider local retouching treatments as an option that would protect the exposed metal substrate and restore the aesthetic integrity, thus postponing a very costly and invasive overall repainting. Unfortunately, matching colour gloss and texture on large monochrome surfaces is always challenging. This paper reports on research undertaken to investigate some of the materials and application techniques that co...

  13. Visiting Richard Serra’s Promenade sculpture improves postural control and judgment of subjective visual vertical.

    Directory of Open Access Journals (Sweden)

    Zoï eKapoula

    2014-12-01

    Full Text Available Body sway while maintaining an upright quiet stance reflects an active process of balance based on the integration of visual, vestibular, somatosensory and proprioceptive inputs. Richard Serra’s Promenade sculpture featured in the 2008 Monumenta exhibition at the Grand Palais in Paris, France is herein hypothesised to have stimulated the body’s vertical and longitudinal axes as it showcased 5 monumental rectangular solids pitched at a 1.69° angle.Using computerised dynamic posturography we measured the body sway of 23 visitors when fixating a cross, or when observing the artwork (fixating it or actively exploring it with eye movements before and after walking around and alongside the sculpture (i.e., before and after a promenade. A first fixation at the sculpture increased medio-lateral stability (in terms of spectral power of body sway. Eye movement exploration in the depth of the sculpture increased antero-posterior stability (in terms of spectral power and cancelling time of body sway at the expense of medio-lateral stability (in terms of cancelling time. Moreover, a medio-lateral instability associated with eye movement exploration before the promenade (in terms of body sway sensu stricto was cancelled after the promenade. Finally, the overall medio-lateral stability (in terms of spectral power increased after the promenade.Fourteen additional visitors were asked to sit in a dark room and adjust a luminous line to what they considered to be the earth-vertical axis. The promenade executed within the sculpted environment afforded by Serra’s monumental statuary works resulted in significantly improved performances on the subjective visual vertical test.We attribute these effects to the sculpted environment provided by the exhibition which may have acted as a kind of physiologic training ground thereby improving the visitors’ overall sense of visual perspective, equilibrium and gravity.

  14. PIXE and {mu}-PIXE analysis of glazes from terracotta sculptures of the della Robbia workshop

    Energy Technology Data Exchange (ETDEWEB)

    Zucchiatti, Alessandro E-mail: zucc@ge.infn.it; Bouquillon, Anne; Lanterna, Giancarlo; Franco, Lucarelli; Mando, Pier Andrea; Prati, Paolo; Salomon, Joseph; Vaccari, Maria Grazia

    2002-04-01

    A series of PIXE analyses has been performed on glazes from terracotta sculptures of the Italian Renaissance and on reference standards. The problems related to the investigation of such heterogeneous materials are discussed and the experimental uncertainties are evaluated, for each element, from the PIXE analysis of standard glasses. Some examples from artefacts coming from Italian collections are given. This research has been conducted in the framework of the COST-G1 European action.

  15. PIXE and μ-PIXE analysis of glazes from terracotta sculptures of the della Robbia workshop

    International Nuclear Information System (INIS)

    Zucchiatti, Alessandro; Bouquillon, Anne; Lanterna, Giancarlo; Franco, Lucarelli; Mando, Pier Andrea; Prati, Paolo; Salomon, Joseph; Vaccari, Maria Grazia

    2002-01-01

    A series of PIXE analyses has been performed on glazes from terracotta sculptures of the Italian Renaissance and on reference standards. The problems related to the investigation of such heterogeneous materials are discussed and the experimental uncertainties are evaluated, for each element, from the PIXE analysis of standard glasses. Some examples from artefacts coming from Italian collections are given. This research has been conducted in the framework of the COST-G1 European action

  16. DOUBLE BOSS SCULPTURED DIAPHRAGM EMPLOYED PIEZORESISTIVE MEMS PRESSURE SENSOR WITH SILICON-ON-INSULATOR (SOI

    Directory of Open Access Journals (Sweden)

    D. SINDHANAISELVI

    2017-07-01

    Full Text Available This paper presents the detailed study on the measurement of low pressure sensor using double boss sculptured diaphragm of piezoresistive type with MEMS technology in flash flood level measurement. The MEMS based very thin diaphragms to sense the low pressure is analyzed by introducing supports to achieve linearity. The simulation results obtained from Intellisuite MEMS CAD design tool show that very thin diaphragms with rigid centre or boss give acceptable linearity. Further investigations on very thin diaphragms embedded with piezoresistor for low pressure measurement show that it is essential to analyse the piezoresistor placement and size of piezoresistor to achieve good sensitivity. A modified analytical modelling developed in this study for double boss sculptured diaphragm results were compared with simulated results. Further the enhancement of sensitivity is analyzed using non uniform thickness diaphragm and Silicon-On-Insulator (SOI technique. The simulation results indicate that the double boss square sculptured diaphragm with SOI layer using 0.85μm thickness yields the higher voltage sensitivity, acceptable linearity with Small Scale Deflection.

  17. The microbial community characteristics of ancient painted sculptures in Maijishan Grottoes, China.

    Science.gov (United States)

    Duan, Yulong; Wu, Fasi; Wang, Wanfu; He, Dongpeng; Gu, Ji-Dong; Feng, Huyuan; Chen, Tuo; Liu, Guangxiu; An, Lizhe

    2017-01-01

    In this study, a culture-independent Illumina MiSeq sequencing strategy was applied to investigate the microbial communities colonizing the ancient painted sculptures of the Maijishan Grottoes, a famous World Cultural Heritage site listed by UNESCO in China. Four mixed samples were collected from Cave 4-4 of the Maijishan Grottoes, the so-called Upper Seven Buddha Pavilion, which was built during the Northern Zhou Dynasty (557-581AD). The 16/18S rRNA gene-based sequences revealed a rich bacterial diversity and a relatively low fungal abundance, including the bacterial groups Actinobacteria, Acidobacteria, Bacteroidetes, Cyanobacteria, Chloroflexi, Firmicutes, Proteobacteria and Verrucomicrobia and the fungal groups Ascomycota, Basidiomycota and Chytridiomycota. Among them, the bacteria genera of Pseudonocardia and Rubrobacter and unclassified fungi in the order of Capnodiales were dominant. The relative abundance of Pseudonocardia in the painted layer samples was higher than that in the dust sample, while Cyanobacteria dominated in the dust sample. Many of them have been discovered at other cultural heritage sites and associated with the biodeterioration of cultural relics. The presence and activity of these pioneering microorganisms may lead to an unexpected deterioration of the painted sculptures that are preserved in this heritage site. Thus, proper management strategies and potential risk monitoring should be used in the Maijishan Grottoes to improve the conservation of these precious painted sculptures.

  18. Archaeometric characterization and provenance determination of sculptures and architectural elements from Gerasa, Jordan

    Science.gov (United States)

    Al-Bashaireh, Khaled

    2018-02-01

    This study aims at the identification of the provenance of white marble sculptures and architectural elements uncovered from the archaeological site of Gerasa and neighboring areas, north Jordan. Most of the marbles are probably of the Roman or Byzantine periods. Optical microscopy, X-ray diffraction, and mass spectrometry were used to investigate petrographic, mineralogical and isotopic characteristics of the samples, respectively. Analytical results were compared with the main reference databases of known Mediterranean marble quarries exploited in antiquity. The collected data show that the most likely main sources of the sculptures were the Greek marble quarries of Paros-2 (Lakkoi), Penteli (Mount Pentelikon, Attica), and Thasos-3 (Thasos Island, Cape Vathy, Aliki); the Asia Minor marble quarries of Proconessus-1 (Marmara) and Aphrodisias (Aphrodisias); and the Italian quarry of Carrara (Apuan Alps). Similarly, the Asia Minor quarries of the fine-grained Docimium (Afyon) and the coarse-grained Proconessus-1 (Marmara) and Thasos-3 are the most likely sources of the architectural elements. The results agree with published data on the wide use of these marbles for sculpture and architectural elements.

  19. Neutron activation analysis applied to assemblage problems in fragmented marble sculptures

    International Nuclear Information System (INIS)

    Sangermano, L.R.

    1976-01-01

    One of the major problems encountered in assemblage work on fragmented marble sculptures is determining if two pieces were originally joined together when there are no remaining material links between the two. This work deals with solving this problem by using Neutron Activation Analysis techniques. Samples from a block of sculpture grade Georgian marble were analyzed. The following trace elements were identified on the basis of their gamma ray energies and their half-life studies: 165 Dy, 155 Sm, 152 Eu, 56 Mn, 24 Na, 85 Sr, 51 Ti, 80 Br, 27 Mg, 52 V, 42 K, 28 Al, 46 Sc, 141 Ce, 198 Au, 140 La, 122 Sb, and 124 Sb. The next step in this work was to determine whether the trace elements, which were originally trapped in the marble during metamorphosis, formed concentration patterns which extended over short distances in the stone. A block of sculpture grade Colorado marble was cut into a number of slices and these slices were analyzed for the trace elements they contained. The concentration patterns formed by these impurities were followed through successive layers of the stone. The ability to follow these ''fingerprint'' concentration patterns over short distances in marble was further tested by analyzing two adjoining segments of a Roman wall relief at the J. Paul Getty Museum in Malibu, California. The trace impurity ''fingerprints'' were successfully matched between the wrist and hand segments of this piece

  20. Photographs of Sculpture: Greek Slave’s ‘complex polyphony’, 1847–77

    Directory of Open Access Journals (Sweden)

    Patrizia Di Bello

    2016-06-01

    Full Text Available This article explores some of the representations, iterations, and appearances of Hiram Powers’s 'Greek Slave' in London in the decades after its first exhibition in 1845, years in which a variety of new ‘engines of the fine arts’ were fuelling a widening market for art objects of all kinds, and popular culture could turn statues into celebrities appearing everywhere — exhibitions, photographers’ studios, newspapers, 'tableau-vivant' shows, even confectionery shops. The article’s focus is on how sculpture was used in the reception and understanding of photography as a new medium of reproduction, and how the materiality of specific photographic ‘objects’ — daguerreotypes, paper prints, and stereographs — interacted with that of sculpture to affect the viewer, at a time when sculptural objects themselves blurred the boundaries between original and reproduction. The article ends with an analysis of stereoscopic cards of 'Greek Slave', as the first photographic reproductions that could really compete with wood engravings and statuettes in the dissemination and circulation of statues, arguing for their pleasurable interactivity as key to their success.

  1. "Lesbians are not women": feminine and lesbian sensibilities in Harmony Hammond's late-1970s sculpture.

    Science.gov (United States)

    Thompson, Margo Hobbs

    2008-01-01

    Harmony Hammond's wrapped fabric sculptures are placed in context of the theories of gender and sexuality that circulated among lesbian and straight feminists at the time they were made, the late 1970s. Hammond has cited in particular Monique Wittig's novels, such as The Lesbian Body, and her essays including "The Straight Mind" where Wittig concludes that the lesbian is not a woman. The critique to which Wittig's lesbian separatism has been subjected by Judith Butler in her consideration of the appeal and limitations of essentialism also applies to Hammond's art. Hammond's use of vaginal imagery was instrumental to visualizing a lesbian sensibility, but the proposition of such a sensibility established a new problematic: a new essential category. The article concludes that because Hammond's work was produced in the context of a complex set of discourses, lesbian, feminist, and aesthetic, it resisted reduction to a singular meaning. Her sculptures avoided the pitfall of substituting one essence for another, lesbian for feminine sensibility, but activated both. The sculptures effectively queered vaginal imagery: When Hammond used vaginal imagery to represent lesbian sensibility, she subverted the equation of sex and gender and the essentialist notion of feminine sensibility.

  2. 3D Reconstruction and Restoration Monitoring of Sculptural Artworks by a Multi-Sensor Framework

    Directory of Open Access Journals (Sweden)

    Sandro Barone

    2012-12-01

    Full Text Available Nowadays, optical sensors are used to digitize sculptural artworks by exploiting various contactless technologies. Cultural Heritage applications may concern 3D reconstructions of sculptural shapes distinguished by small details distributed over large surfaces. These applications require robust multi-view procedures based on aligning several high resolution 3D measurements. In this paper, the integration of a 3D structured light scanner and a stereo photogrammetric sensor is proposed with the aim of reliably reconstructing large free form artworks. The structured light scanner provides high resolution range maps captured from different views. The stereo photogrammetric sensor measures the spatial location of each view by tracking a marker frame integral to the optical scanner. This procedure allows the computation of the rotation-translation matrix to transpose the range maps from local view coordinate systems to a unique global reference system defined by the stereo photogrammetric sensor. The artwork reconstructions can be further augmented by referring metadata related to restoration processes. In this paper, a methodology has been developed to map metadata to 3D models by capturing spatial references using a passive stereo-photogrammetric sensor. The multi-sensor framework has been experienced through the 3D reconstruction of a Statue of Hope located at the English Cemetery in Florence. This sculptural artwork has been a severe test due to the non-cooperative environment and the complex shape features distributed over a large surface.

  3. Sculptured platinum nanowire counter electrodes for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeonseok [Department of Electrical Engineering, Pennsylvania State University, University Park 16802 (United States); Horn, Mark W., E-mail: MHorn@engr.psu.edu [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park 16802-6812 (United States)

    2013-07-01

    Sculptured platinum nanowire thin films were formed by oblique angle electron beam evaporation with a 5° vapor incidence angle and incorporated as counter electrodes for dye-sensitized solar cells (DSSCs). For the comparison of the performance, bare fluorine doped tin oxide, planar Pt electrodes and counter electrodes treated with chloroplatinic acid were prepared. The sculptured Pt nanowire electrodes showed five times lower charge transfer resistance (0.121 [Ω∗cm{sup 2}]) than that of Pt planar electrode (0.578 [Ω∗cm{sup 2}]) and when the Pt nanowire electrodes are treated with an H{sub 2}PtCl{sub 6} solution have more than ten times lower charge transfer resistance (0.04025 [Ω∗cm{sup 2}]). Moreover, Pt nanowire films used as a counter electrode lead to enhancement in current density and efficiency in comparison with Pt planar counter electrodes. The conversion efficiency with planar electrodes was 5.1 [%] while the efficiency of DSSC with platinum nanowire counter electrodes reached to 5.63 [%] under AM 1.5 illumination. - Highlights: • Pt sculptured thin films (STFs) fabricated by electron beam evaporator. • The STFs featured higher roughness and lower charge transfer resistance. • Improved performance of dye-sensitized solar cells by Pt STFs counter electrodes.

  4. Ice Cores

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature, precipitation, atmospheric trace gases, and other aspects of climate and environment derived from ice cores drilled on glaciers and ice...

  5. Ice Cream

    NARCIS (Netherlands)

    Scholten, E.

    2014-01-01

    Ice cream is a popular dessert, which owes its sensorial properties (mouth feel) to its complex microstructure. The microstructure is a result of the combination of the ingredients and the production process. Ice cream is produced by simultaneous freezing and shearing of the ice cream mix, which

  6. Ice targets

    International Nuclear Information System (INIS)

    Pacheco, C.; Stark, C.; Tanaka, N.; Hodgkins, D.; Barnhart, J.; Kosty, J.

    1979-12-01

    This report presents a description of ice targets that were constructed for research work at the High Resolution Spectrometer (HRS) and at the Energetic Pion Channel and Spectrometer (EPICS). Reasons for using these ice targets and the instructions for their construction are given. Results of research using ice targets will be published at a later date

  7. The Evaluation of Efficacy of the Combination of Acoustic Cavitation and Radiofrequency Lipolysis in Body Sculpturing

    Directory of Open Access Journals (Sweden)

    Seval Dogruk Kacar

    2014-02-01

    Full Text Available Aim: There is widespread use of noninvasive body sculpturing methods with the emerging new technologies in the field of aesthethic dermatology. However scientific data about these methods is limited. In our study the efficacy of the combination of acoustic cavitation and radiofrequency in body sculpturing is retrospectively evaluated. Material and Method: We retrospectively evaluated the patients who underwent body contouring treatment for belly and waist area in Dermatocosmetology unit of Afyon Kocatepe University Hospital between September 2012 and September 2013. The combination of acoustic cavitation and radiofrequency is applied 2 times a week for 10 sessions for body contouring of waist and belly. Before treatment and after each session the height, weight and perimetric measurements are recorded. Patients satisfaction level is assessed by visual analogue scale (VAS between 0 (dissatisfied, no effect and 5 (very satisfied, very effective. Results: The mean age of 15 female patients were 36,4±10,2 (23-52. There were statistically significant difference in weight and perimetric measurements of waist (superior waist, waist circumference, inferior waist between the beginning and end of treatment (respectively, p=0.002 and p=0.001 for the remaining three. Sixty percent of patients described the treatment as satisfactory according to VAS. The remaining were not satisfied although the treatments produced a change. No adverse effects reported other than a transient erythema during treatment. Discussion: Diet and exercise are still the most relevant ways to achieve optimal body shape and tone. Besides it is possible to eliminate excess fat and skin in appropriate patients by body sculpturing methods such as invasive and noninvasive liposuction and lipolysis. We found the combination of acoustic cavitation and radiofrequency effective in body shaping.

  8. Soluble salt sources in medieval porous limestone sculptures: A multi-isotope (N, O, S) approach

    Energy Technology Data Exchange (ETDEWEB)

    Kloppmann, W., E-mail: w.kloppmann@brgm.fr [BRGM, Direction des Laboratoires, Unité Isotopes, BP 6009, F-45060 Orléans cedex 2 (France); Rolland, O., E-mail: olivierrolland@wanadoo.fr [Montlouis-sur-Loire (France); Proust, E.; Montech, A.T. [BRGM, Direction des Laboratoires, Unité Isotopes, BP 6009, F-45060 Orléans cedex 2 (France)

    2014-02-01

    The sources and mechanisms of soluble salt uptake by porous limestone and the associated degradation patterns were investigated for the life-sized 15th century “entombment of Christ” sculpture group located in Pont-à-Mousson, France, using a multi-isotope approach on sulphates (δ{sup 34}S and δ{sup 18}O) and nitrates (δ{sup 15}N and δ{sup 18}O). The sculpture group, near the border of the Moselle River, is within the potential reach of capillary rise from the alluvial aquifer. Chemical analyses show a vertical zonation of soluble salts with a predominance of sulphates in the lower parts of the statues where crumbling and blistering prevail, and higher concentrations of nitrates and chloride in the high parts affected by powdering and efflorescence. Isotope fingerprints of sulphates suggest a triple origin: (1) the lower parts are dominated by capillary rise of dissolved sulphate from the Moselle water with characteristic Keuper evaporite signatures that progressively decreases with height; (2) in the higher parts affected by powdering the impact of atmospheric sulphur becomes detectable; and (3) locally, plaster reparations impact the neighbouring limestone through dissolution and re-precipitation of gypsum. Nitrogen and oxygen isotopes suggest an organic origin of nitrates in all samples. N isotope signatures are compatible with those measured in the alluvial aquifer of the Moselle River further downstream. This indicates contamination by sewage or organic fertilisers. Significant isotopic contrasts are observed between the different degradation features depending on the height and suggest historical changes of nitrate sources. - Highlights: • We use S, N and O isotopes to distinguish salt sources in limestone sculptures. • Vertical zonation of degradation is linked to capillary rise and air pollution. • Sulphate salts in lower parts are derived from river/groundwater. • Sulphate salts in higher parts show signature of air pollution. • Nitrates

  9. Nondestructive insights into composition of the sculpture of Egyptian Queen Nefertiti with CT.

    Science.gov (United States)

    Huppertz, Alexander; Wildung, Dietrich; Kemp, Barry J; Nentwig, Tanja; Asbach, Patrick; Rasche, Franz Maximilian; Hamm, Bernd

    2009-04-01

    To assess the conservation status of, to gain information on the creation of, and to provide surface reformations of the core and the surface of the bust of the pharaoh-queen Nefertiti, considered to be one of the greatest treasures of ancient Egyptian art, with computed tomography (CT). Multisection CT was performed with 0.6-mm section thickness. Two- and three-dimensional reformations were made to depict the core and the surface separately. The stucco layer on the face and the ears was very thin, a maximum of 1-2 mm thick. The rear part of the reconstructed crown showed two thick stucco layers of different attenuation values, indicating that a multistep process was used to create the sculpture. Within the stucco, a great number of air-equivalent hypoattenuating areas, filamentous fissures parallel to the surface, and an inhomogeneous bonding between the layers were delineated. Nefertiti's inner face was not anonymous, but rather delicately sculpted by the royal sculptor Thutmose. The comparison to the outer face revealed differences, including the angles of the eyelids, creases around the corners of the mouth on the limestone surface, and a slight bump on the ridge of the nose. According to the beauty ideals of the Amarna period, the differences had positive and negative effects and can be read as signs of individualization of the sculpture. The potential material-related weaknesses of the sculpture that were revealed at imaging necessitate careful handling, with the avoidance of any focal pressure and shearing forces in the crown and the shoulders. CT imaging revealed construction techniques in Nefertiti's bust that had implications for conservation, as well as for an understanding of the artistic methods used in the creation of this masterpiece of art of the 18th dynasty.

  10. SPECIFIC FEATURES OF THE PORTRAIT IN NATIONAL PAINTING AND SCULPTURE (1945-1960

    Directory of Open Access Journals (Sweden)

    LOZOVANU VLADIMIR

    2016-12-01

    Full Text Available The present article is devoted to the peculiarities of the portrait in national painting and sculpture in the period of the 1950s. The text refl ects the creation of prominent artists who have realized the most famous portrait works. The author presents examples of representative portraits and they are analysed in the context of the period we refer to. He identifies both the methods, techniques, the ideas and aspiration of plastic artists who have practised portrait art. the presented information is useful to artists and teachers working in the fi eld of visual arts and to students who are interested in portrait painting.

  11. Sea Ice

    Science.gov (United States)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  12. Model Making and Anti-Competitive Practices in the Late Eighteenth-Century London Sculpture Trade

    Directory of Open Access Journals (Sweden)

    Craske, Matthew

    2014-03-01

    Full Text Available This article concerns the generation of anti-competitive practices, and the associated discontents, that rose to the fore in the London sculpture trade in the late eighteenth century (1770-1799. It charts the business strategies and technical procedures of the most economically successful practitioners, whose workshops had some of the characteristics of manufactories, and whose critics accused them of conducting a "monopoly" trade. Small-scale practitioners lost out in the competition for great public contracts on account of their design processes and their inability to represent any manifestation of "establishment". A combination of three factors increased the gap between a handful of powerful "manufacturers" and the rest of the trade: the foundation of the Royal Academy, shifts in the ways designs were evaluated, and a growing number of very lucrative contracts for public sculpture. I conclude that such were the discontents within the London trade that by the 1790s, there was a marked tendency for practitioners who were not manufacturers to be attracted to democratic political movements, to the Wilkite call for liberty and the rise of civic radicalism in the merchant population of London.

  13. Alison Gill – "To See a World", an exhibition of new sculpture and works on paper

    CERN Multimedia

    2013-01-01

    Wednesday, 11 December 2013 from 4 p.m. to 5 p.m. in the Library, bldg. 52 1-052 "Sculpture stories and invisible things" How might the presence of an artist influence the CMS experiment? And how does the LHC change the artist and the work they make? Over the last two decades, I have worked with a wide range of media to create both sculpture and drawing. The interdisciplinary approach that I have taken has often involved engagement and dialogues with scientists. Through my art, I explore the stories we tell to make sense of things that seem beyond our conscious grasp, taking familiar objects and materials and re-purposing, casting or altering the meaning. Underlying themes have included folklore, beliefs and methods used in the pursuit of transcendence. Knots, Klein bottles and Möbius strips have also been used for their topological, emotive and metaphysical associations. I try to scrutinise the world around me to find hidden meanings and use humour to provoke thought, elicit c...

  14. Transparent sculptured titania films for enhanced light absorption in thin-film Si solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Kai-Hsiang, E-mail: khhung@itri.org.tw [Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan (China); Chiou, Guan-Di; Wong, Ming-Show [Department of Materials Science and Engineering, National Dong Hwa University, Hualien, Taiwan (China); Wang, Yu-Chih [Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan (China); Chung, I-Shan [Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan (China)

    2011-12-30

    This study presents a description of the enhancement of light absorption in thin-film silicon (Si) solar cells by using sculptured titania (TiO{sub 2}) films. We used an electron-beam evaporation system with a glancing angle deposition (GLAD) method to deposit porous TiO{sub 2} films on fluorine-doped SnO{sub 2} (FTO) substrates. The GLAD TiO{sub 2}/FTO films were used as conductive electrodes in hydrogenated microcrystalline silicon ({mu}c-Si:H) solar cells. Transmission electron microscopy revealed that the GLAD TiO{sub 2} films are composed of sculptured nano-pillars on an FTO surface, and this nanostructure provides a synergistic route for light scattering enhancement. The GLAD TiO{sub 2}/FTO exhibited a 68% improvement of optical haze (at {lambda} = 600 nm). The {mu}c-Si:H solar cells consisting of the GLAD-nanostructured TiO{sub 2} resulted in a 5% improvement of short-circuit current (J{sub sc}) and yielded a cell efficiency of 6.6%.

  15. Joep van Lieshout's Mobile Home for Kröller-Müller: outdoor polyester sculpture in transit

    NARCIS (Netherlands)

    Stigter, S.; Beerkens, L.; Schellen, H.L.; Kuperholc, S.; Bridgland, J.

    2008-01-01

    The nature and condition of the large scale glass fibre reinforced polyester resin outdoor sculpture by Dutch artist Joep van Lieshout: Mobile Home for Kröller-Müller (1995) is challenging traditional conservation ethics. Chemists, physicists, art historians, conservators specialised in different

  16. Outdoor polyester sculpture in transit: Joep van Lieshout’s Mobile Home for Kröller-Müller

    NARCIS (Netherlands)

    Stigter, S.; Beerkens, L.; Schellen, H.L.; Kuperholc, S.

    2008-01-01

    The nature and condition of the largescale glass fibre reinforced polyester resin outdoor sculpture by Dutch artist Joep van Lieshout: Mobile Home for Kröller-Müller (1995) is challenging traditional conservation ethics. Chemists, physicists, art historians, conservators specialised in different

  17. Spines vs. microspines: an overview of the sculpture exine in selected basal and derived Asteraceae with focus on Asteroideae.

    Science.gov (United States)

    Tellería, María C

    2017-11-01

    This study presents a detailed examination of the echinate and microechinate sculpturing in relation to the size of pollen grains in 31 selected species of Asteraceae belonging to the subfamilies Barnadesioideae, Mutisioideae, Carduoideae and Asteroideae. The aims were to recognize sculpturing patterns, under LM and SEM, within large and small pollen of both basal and derived species and to explore the features that could have taxonomic value to apply in palynological disciplines. The detailed examination of the exine surface showed both the relevance and limits of sculptural patterns for taxonomy. Under LM, the microechinate sculpture gave little taxonomic information, whereas in the echinate sculpture, three exine types and two subtypes were recognized. Type I included microechinate exine, which is commonly present in large pollen grains of the basal lineages. Types II (subtypes IIa and IIb) and III included echinate and smaller pollen grains. In these types, spines were always regularly arranged and, were characterized by the length, shape, tip, perforations and distribution. Type IIa included more or less conical spines usually with a distended base, less than 4 µm in length, present in species of different tribes like Astereae, Eupatorieae, Helenieae, Gnaphalieae, Senecioideae and Heliantheae to a lesser extent. Type IIb includes slender spines with narrower bases, longer than 4 µm, present in species of Coreopsideae, Heliantheae, Tageteae and Eupatorieae to a lesser extent. Type III included spines with swollen base, blunt tip and perforations over their entire surface. This type was present in only one of the basal species-Carduus thoermeri-and in one species of the derived tribe Helenieae, Gaillardia megapotamica. Probably, this is due to evolutionary convergence.

  18. A highly sensitive multiplasmonic sensor using hyperbolic chiral sculptured thin films

    Science.gov (United States)

    Abbas, Farhat; Faryad, Muhammad

    2017-11-01

    Surface plasmon-polariton (SPP) waves guided by an interface of a metal and a hyperbolic chiral sculptured thin film (STF) were theoretically investigated for optical sensing of an analyte. The chiral STF was infiltrated with the analyte to be sensed, and the resulting change in the incidence angle of excitation of the SPP waves in the prism-coupled configuration was computed. The results indicated the potential of this configuration for a plasmonic sensor with sensitivity up to 6000 degrees per refractive index units of the infiltrating fluid in the angular investigation scheme, with multiple SPP waves of the same frequency but different phase speeds, spatial profiles, and sensitivities. The enhancement in the sensitivity is attributed to the high field strength of the SPP waves near the interface. A multiplasmonic sensor is advantageous because of its potential for higher confidence in the measurement of the same analyte.

  19. The morphology and sculpture of ossicles in the Cottidae (Teleostei of the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Heli Špilev

    2010-09-01

    Full Text Available Small to very small ossified structures (ossicles such as cephalic horns, dermal tubercles, fin-ray rods, lateral-line canal segments, branchial tooth plates and gill-raker tubercles of three species of the teleostean fish family Cottidae inhabiting the Baltic Sea are described and for the first time illustrated with SEM images, with emphasis on their microscopic external features. The morphology and sculpture of these small ossicles notably differ in the three genera, but differences can also occur between males and females, as documented here in Myoxocephalus scorpius (Linnaeus. The detailed features of such ossicles are potentially useful for taxonomic identification in sea-floor sediments or gut contents, in a manner similar to their use in many modern and fossil fishes, and may also prove useful as phylogenetically important characters at generic and familial levels.

  20. From Soft Sculpture to Soft Robotics: Retracing a Physical Aesthetics of Bio-Morphic Softness

    DEFF Research Database (Denmark)

    Jørgensen, Jonas

    2017-01-01

    Soft robotics has in the past decade emerged as a growing subfield of technical robotics research, distinguishable by its bio-inspired design strategies, interest in morphological computation, and interdisciplinary combination of insights from engineering, computer science, biology and material...... science. Recently, soft robotics technology has also started to make its way into art, design, and architecture. This paper attempts to think an aesthetics of softness and the life-like through an artistic tradition deeply imbricated with an interrogation of softness and its physical substrates, namely...... the soft sculpture that started proliferating in the late 1960s. Critical descriptions of these works, interestingly, frequently emphasize their similarities with living organisms and bodies as a central tenet of their aesthetics. The paper seeks to articulate aspects of a contiguity between softness...

  1. Educational process their different contents, singularities to the sculpture the Formation integral in university students

    Directory of Open Access Journals (Sweden)

    Laura Margarita Fernández-Martínez

    2018-03-01

    Full Text Available Presently article is approached important relating theoretical the in artistic education, that facilitate the formation integral in university students, the educational process their different contents, singularities to the sculpture artistic manifestation, with which one works methodologically. However, it is necessary to establish a methodological theoretical position in this respect to be able to evidence the relationship education-culture the understanding of the artistic education in that relationship and their contribution to the formation integral. From the didactic point of view, it is sustained in the basics of the teaching-learning process, related with the Didactics of the Superior Education and in the analysis and valuation of the components of the process of teaching learning where the dynamics of the relationships is revealed among these that it is constituted in a dialectical process where starting from the created conditions the fellow appropriates of the necessary tools for interaction with the reality.

  2. Using Soft Sculpture Microfossils and Other Crafted Models to Teach Geoscience

    Science.gov (United States)

    Spinak, N. R.

    2017-12-01

    For the past 5 years, the International Ocean Discovery Program (IODP) has been using the author's sewn models of microfossils to help learners understand the shapes and design of these tiny fossils. These tactile objects make the study of ancient underwater life more tangible. Multiple studies have shown that interactive models can help many learners understand science. The Montessori and Waldorf education programs are based in large part on earlier insights into meeting these needs. The act of drawing has been an essential part of medical education. The STEAM (Science, Technology, Engineering, Arts and Math) movement has advocated for STEM supporters to recognize the inseparability of science and art. This presentation describes how the author's knitted or sewn models of microfossils incorporate art and design into geoscience education. The geoscience research and art processes used in developing and creating these educational soft sculptures will be described. In multiple entry points to science study, specific reciprocal benefits to boundary crossing among the arts and sciences for those who have primary talents in a particular area of study will be discussed. Geoscience education can benefit from using art and craft items such as models. Many websites now offer soft sculptures for biology study such as organs and germs (e.g. (https://www.giantmicrobes.com/us/main/nasty-germs). The Wortheim project involving community and crochet is another approach (http://crochetcoralreef.org/). These tactile artifacts give learners an entry-level experience with biology. Three dimensional models are multisensory. The enlarged manipulative microfossil models invite learners to make comparisons and gain insights when microscopes are not available or appropriate for the audience. Adding the physical involvement of creating a microfossil yourself increases the multi-sensory experience even further. Learning craft skills extends the cross-cutting concepts of the NGSS to a mutual

  3. Thin-section microscopy of decayed crystalline marble from the garden sculptures of Schoenbrunn Palace in Vienna

    International Nuclear Information System (INIS)

    Weber, J.; Beseler, S.; Sterflinger, K.

    2007-01-01

    Sterzing marble, a crystalline white marble used in the late-Baroque garden sculptures of Schoenbrunn Palace in Vienna, was studied by means of thin-section and scanning electron microscopy in order to obtain a better understanding of its surface decay caused by atmospheric weathering. Following the classification of distinct phenomena of deterioration by visual on-site inspection, the microstructural features including surface erosion, micro-cracking, soiling, black crust formation, and microbiological infestation are exemplified by microscopical images and are briefly discussed. The results proved useful for evaluating and understanding the various types of marble decay for creating a safer basis for establishing the procedural principles aimed at conservation and maintenance of the sculptures

  4. Ice Ages

    Indian Academy of Sciences (India)

    that the precession of the earth's orbit caused ice ages. The precession of the earth's orbit leads to changes in the time of the year at which ... than in the southern hemisphere. ..... small increase in ocean temperature implies a large increase in.

  5. Nano-structure and optical properties (plasmonic) of graded helical square tower-like (terraced) Mn sculptured thin films

    Energy Technology Data Exchange (ETDEWEB)

    Savaloni, Hadi, E-mail: savaloni@khayam.ut.ac.ir [Department of Physics, University of Tehran, North-Kargar Street, Tehran (Iran, Islamic Republic of); Fakharpour, Mahsa [Department of Physics, Islamic Azad University, Science and Research Branch, Tehran (Iran, Islamic Republic of); Siabi-Garjan, Araz [Department of Advanced Technologies, University of Mohaghegh Ardabili, Namin, Ardabil (Iran, Islamic Republic of); Department of Materials Engineering and Nanotechnology, Sabalan University of Advanced Technologies (SUAT), Namin (Iran, Islamic Republic of); Placido, Frank [SUPA and Institute of Thin Films, Sensors and Imaging, University of The West of Scotland, High Street, Paisley (United Kingdom); Babaei, Ferydon [Department of Physics, University of Qom, Qom (Iran, Islamic Republic of)

    2017-01-30

    Highlights: • Graded helical square tower-like terraced sculptured Mn thin films are produced with different number of arms. • XRD, AFM, FESEM and optical analyses as well as theoretical calculations are carried out. • Intensity of Plasmon peaks depend on the polarization, the incident angle, and the distance from the shadowing block. • The presence of defects in these sculptured structures can be predicted by theoretical investigation. • Experimental and theoretical investigations show consistent results. - Abstract: Graded helical square tower-like terraced sculptured Mn thin films (GHSTTS) are produced in three stages with different number of arms using oblique angle deposition together with rotation of substrate holder about its surface normal, plus a shadowing block fixed at the centre of the substrate holder. The structural characterization of the produced samples was obtained using field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). Results showed a structural gradient with distance from the edge of the shadowing block, which in turn is responsible for the decrease in the volume of void fraction and increase of grain size. Plasmon absorption peaks observed in the optical analysis of these nano-structures showed that their wavelength region and intensity depend on the polarization and the incident angle of light, as well as the distance from the edge of the shadowing block. According to our model and discrete dipole approximation (DDA) calculations, when the number of parallel nano-rods of different lengths and radii are increased the peak in the spectrum shifts to shorter wavelengths (blue shift). Also when the diameters of the nano-rods increases (a situation that occurs with increasing film thickness) the results is again a blue shift in the spectrum. The presence of defects in these sculptured structures caused by the shadowing effect is predicted by the theoretical DDA investigation of their optical spectra

  6. The conservation treatment of a contemporary collaged sculpture by Jiří Kolář (1914-2002

    Directory of Open Access Journals (Sweden)

    Jessica Crann

    2010-11-01

    Full Text Available Une sculpture représentant une pomme réalisée par collage de l’artiste tchèque Jiří Kolář et datant de 1972, a été soumise à un traitement de conservation-restauration. La sculpture présentait des dommages structurels causés par des facteurs externes ainsi que des surfaces encrassées. Les interrogations déontologiques soulevées lors de la restauration d’une œuvre d’art contemporain ont représenté un aspect important de l’étude. Par conséquent, la majeure partie des recherches a été dévolue à  la compréhension du matériau et de la structure, celle des intentions de l’artiste,tout comme du concept et de la signification de l’œuvre. Ce travail a été étayé par une recherche scientifique ayant pour but d’évaluer l’efficacité du Triammonium citrate comme agent de nettoyage à base aqueuse, ainsi que par une analyse de la construction en trois dimensions de l’œuvre d’art.A collaged sculpture of an apple by the Czech artist Jiří Kolář, dated 1972 was presented for conservation. The sculpture suffered from structural damage caused by external factors and ingrained surface dirt. The ethical implications raised in conserving a contemporary artwork were an important aspect and subsequently an understanding of the materials and structure, the artist’s intentions, concept and meaning of the artwork formed a large part of the research. Combined with this was scientific research into the effectiveness of Tri-ammonium Citrate as an aqueous surface cleaning agent and analysing construction of 3-Dimensional artworks.

  7. Petrographic characterization and provenance determination of the white marbles used in the Roman sculptures of Forum Sempronii (Fossombrone, Marche, Italy)

    Science.gov (United States)

    Antonelli, Fabrizio; Columbu, Stefano; Lezzerini, Marco; Miriello, Domenico

    2014-06-01

    The Roman municipium of Forum Sempronii (Fossombrone, Marche) was located along the `Via Consolare Flaminia', in the stretch of road where it ran along the final sector of the valley of the River Metauro ( Mataurus). The ancient colony of Forum Sempronii, which is cited by Strabo, Pliny, and Ptolemy, was found in the second century BC, probably on the site of an earlier community and its activity continued until the end of the fifth century AD. During ancient and more recent archaeological excavations, many fragments of coloured stones and marbles, and some white marble sculptures have been unearthed. In this paper, we report the results of the provenance identification of the white marbles used for the sculptures found in the archaeological site of Forum Sempronii and now displayed at the local archaeological museum. The determination of the source origin of the white marbles used for the sculptures has been established by mineralogical-petrographic and geochemical analyses. Microscopic study of thin sections together with carbon and oxygen stable isotope ratios indicate that more than one type of white marbles was used: Pentelikon, Lunense, and Thasian.

  8. Eulerian Method for Ice Crystal Icing

    NARCIS (Netherlands)

    Norde, Ellen; van der Weide, Edwin Theodorus Antonius; Hoeijmakers, Hendrik Willem Marie

    In this study, an ice accretion method aimed at ice crystal icing in turbofan engines is developed and demonstrated for glaciated as well as mixed-phase icing conditions. The particle trajectories are computed by an Eulerian trajectory method. The effects of heat transfer and phase change on the

  9. Stereoscopic CAD and Environmental Sculpture: Enhancement of the Design Process in the Visual Arts

    Science.gov (United States)

    Fisher, Robert N.; Bandini, Pier L.

    1989-09-01

    In this paper, co-authors Robert Fisher and Pier Luigi Bandini describe their personal observations concerning stereo enhancements of computer graphics images employed in their research. in Part One, Robert Fisher, a professional sculptor, Professor and Artist-in-Residence in the College of Engineering at Penn State, cites three recent environmental sculpture projects: "See-scape," "A Page from the Book of Skies," and an as yet untitled work. Wireframe images, interior views of architectural spaces, and complex imagery are rendered comprehensible by stereo 3-D. In Part Two, Pier L. Bandini, Associate Professor of Architecture and Director of the Architecture CAD Lab at Penn State, describes the virtues of the stereo-enhanced wireframe model--the benefits of the "see-through coupled with a complete awareness of the whole space." The final example, of a never-realized XVIII-century project, suggests a new and profound application of stereo 3-D to historical inquiry, namely, the experience of ancient spaces and structures that are no longer existing or that were never constructed.

  10. [Diprosopus triophthalmus. From ancient terracotta sculptures to spiral computer tomographic reconstruction].

    Science.gov (United States)

    Sokiranski, R; Pirsig, W; Nerlich, A

    2005-03-01

    A still-born male fetus from the 19th century, fixed in formalin and presenting as diprosopia triophthalmica, was analysed by helical computer tomography and virtually reconstructed without damage. This rare, incomplete, symmetrical duplication of the face on a single head with three eyes, two noses and two mouths develops in the first 3 weeks of gestation and is a subset of the category of conjoined twins with unknown underlying etiology. Spiral computer tomography of fixed tissue demonstrated in the more than 100 year old specimen that virtual reconstruction can be performed in nearly the same way as in patients (contrast medium application not possible). The radiological reconstruction of the Munich fetus, here confined to head and neck data, is the basis for comparison with a number of imaging procedures of the last 3000 years. Starting with some Neolithic Mesoamerican ceramics, the "Pretty Ladies of Tlatilco", diprosopia triophthalmica was also depicted on engravings of the 16th and 17th century A.D. by artists as well as by the anatomist Soemmering and his engraver Berndt in the 18th century. Our modern spiral computer tomography confirms the ability of our ancestors to depict diprosopia triophthalmica in paintings and sculptures with a high level of natural precision.

  11. Fabrication, characterization and some applications of graded chiral zigzag shaped nano-sculptured silver thin films

    Energy Technology Data Exchange (ETDEWEB)

    Savaloni, Hadi, E-mail: savaloni@khayam.ut.ac.ir [Department of Physics, University of Tehran, North-Kargar Street, Tehran (Iran, Islamic Republic of); Esfandiar, Ali [Department of Physics, University of Tehran, North-Kargar Street, Tehran (Iran, Islamic Republic of)

    2011-09-01

    Graded chiral zig-zag shaped nano-sculptured silver thin films (GCZSSTF) were produced in two stages using oblique deposition technique together with rotation of substrate about its surface normal while a shadowing block was also fixed at Center of the substrate holder. Chrystallographic and morphological structure of these films were obtained using X-ray diffraction (XRD) and atomic force microscopy (AFM). Spectrophotometry was used to obtain their optical behavior while their application in both hydrophobicity and gas sensing was also investigated. XRD results showed a dominant (1 1 1) orientation growth on the zig arm of the structure while by addition of the second arm (zag) the crystallographical growth orientation changed to (2 2 0). The anisotropic nano-structure of these films was also distinguished through (1 - R) spectra. A common peak at about 350 nm related to the TM mode of plasmon resonances and a broad shoulder at about 420 nm for the s-polarized light and at 620 nm for the p-polarized light corresponding to the LM mode of plasmon resonances are observed. These peaks are directly related to the nano-columns topography. The film system used here proved to act as a physical method for producing layer-by-layer structure for obtaining enhanced hydrophobic surfaces rather than the usual chemical methods reported in the literature. In addition, the GCZSSTF also acted as good as reported results for nano-tubes when applied as cathode in the field ionization gas sensing setup.

  12. Sea ice - Multiyear cycles and white ice

    Science.gov (United States)

    Ledley, T. S.

    1985-01-01

    The multiyear thickness cycles represent one of the interesting features of the sea ice studies performed by Semtner (1976) and Washington et al. (1976) with simple thermodynamic models of sea ice. In the present article, a description is given of results which show that the insulating effect of snow on the surface of the sea ice is important in producing these multiyear cycles given the physics included in the model. However, when the formation of white ice is included, the cycles almost disappear. White ice is the ice which forms at the snow-ice interface when the snow layer becomes thick enough to depress the ice below the water level. Water infiltrates the snow by coming through the ice at leads and generally freezes there, forming white ice.

  13. Forecasting Turbine Icing Events

    DEFF Research Database (Denmark)

    Davis, Neil; Hahmann, Andrea N.; Clausen, Niels-Erik

    2012-01-01

    In this study, we present a method for forecasting icing events. The method is validated at two European wind farms in with known icing events. The icing model used was developed using current ice accretion methods, and newly developed ablation algorithms. The model is driven by inputs from the WRF...... mesoscale model, allowing for both climatological estimates of icing and short term icing forecasts. The current model was able to detect periods of icing reasonably well at the warmer site. However at the cold climate site, the model was not able to remove ice quickly enough leading to large ice...

  14. Determination of weathering and conservation of sculptured stone by use of the laser method

    International Nuclear Information System (INIS)

    Aaberg, G.; Stijfhoorn, D.E.

    1996-09-01

    Weathering and deterioration of sculptured stone and masonry is a natural process which stars at the same moment the stone is quarried and exposed to exogenous conditions. This process of natural decay has, however, been accelerated due to the emission of different man-made pollutants, domestic and industrial, local and global. The ISOLASER project is based on the laser microprobe technique for determining the depth of natural and induced weathering and the effect of conservation measures of cultural objects of carbonaceous sandstone and marble/limestone. The purpose of the project is to determine the depth of weathering and depth of penetration of conservation agents in unweathered calcite-cemented stone and the weathering profile in linseed oil-treated stone after accelerated weathering cycles in a climatic chamber. The analytical results show that even after such a short period as five weeks of exposure the effect of SO 2 , NO 2 and elevated humidity on Gotland sandstone can be easily observed in a change of the δ 13 C values in the outermost 2 mm of the stone. Treating the sample with linseed oil has a preserving effect on the rock and hinders the deteriorating effect of SO 2 and NO 2 . The oil treatment even preserves the signature of previously incorporated organic carbon. Compilation of a questionnaire representing a broad field within natural sciences in cultural heritage research in Europe, shows an overwhelming positive approach to the project as such. The questioned researchers consider the laser method particularly useful as a complementary method in other investigations and states that the method can without doubt give new dimensions to the analysis of important cultural objects. 2 refs., 6 figs

  15. Great Lakes Ice Charts

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Charts show ice extent and concentration three times weekly during the ice season, for all lakes except Ontario, from the 1973/74 ice season through the 2001/2002...

  16. Documentation and dissemination of the sculptural elements of Canada's Parliamentary Buildings: Methodology development and evolution, a case study

    Directory of Open Access Journals (Sweden)

    C. Ouimet

    2015-08-01

    Full Text Available Parliament Hill consists of four historic gothic revival buildings, which form part of the Parliament Buildings National Historic Site of Canada in the National Capital of Ottawa. There are more than 2000 masonry sculptural elements throughout the four buildings. Three of the buildings are in the middle of multi-year rehabilitation projects. Extensive Heritage Documentation is being undertaken to support various activities and conservation teams throughout the interior and exterior of the buildings while also serving as a key posterity records. One of the significant heritage documentation projects is the 3D digitization of the 2000+ heritage character defining sculptural elements. The Heritage Conservation Directorate (HCD of Public Works and Government Services Canada (PWGSC was tasked by the Parliamentary Precinct Branch (PPB of PWGSC to document these character defining elements. The sculptures vary in size from as small as 100mm in width to up to 2 meters in size. This project is in its third year and much has been learned and researched about the most appropriate and efficient means by which to document these elements. Although a methodology was in place to document the sculptures at the inception of the project, it has gone through several iterations in order to improve the gathered data, and in turn increase the efficiency, quality and speed of data acquisition. This paper will describe the evolution of the methodology, as well as the rationale for the alterations in technique. With over 600 of the approximate 2000 (heritage character defining sculptural elements captured to date, the project is entering a critical phase where an efficient and effective method for sharing and disseminating the information to a wide audience is being explored and evaluated. The end result is intended to allow the client (PPB and the general public a way to look at and interactively manipulate the viewpoint of each digital model. This will provide a unique

  17. Dead-ice environments

    DEFF Research Database (Denmark)

    Krüger, Johannes; Kjær, Kurt H.; Schomacker, Anders

    2010-01-01

    glacier environment. The scientific challenges are to answer the key questions. What are the conditions for dead-ice formation? From which sources does the sediment cover originate? Which melting and reworking processes act in the ice-cored moraines? What is the rate of de-icing in the ice-cored moraines...

  18. Rate of ice accumulation during ice storms

    Energy Technology Data Exchange (ETDEWEB)

    Feknous, N. [SNC-Lavalin, Montreal, PQ (Canada); Chouinard, L. [McGill Univ., Montreal, PQ (Canada); Sabourin, G. [Hydro-Quebec, Montreal, PQ (Canada)

    2005-07-01

    The rate of glaze ice accumulation is the result of a complex process dependent on numerous meteorological and physical factors. The aim of this paper was to estimate the distribution rate of glaze ice accumulation on conductors in southern Quebec for use in the design of mechanical and electrical de-icing devices. The analysis was based on direct observations of ice accumulation collected on passive ice meters. The historical database of Hydro-Quebec, which contains observations at over 140 stations over period of 25 years, was used to compute accumulation rates. Data was processed so that each glaze ice event was numbered in a chronological sequence. Each event consisted of the time series of ice accumulations on each of the 8 cylinders of the ice meters, as well as on 5 of its surfaces. Observed rates were converted to represent the average ice on a 30 mm diameter conductor at 30 m above ground with a span of 300 m. Observations were corrected to account for the water content of the glaze ice as evidenced by the presence of icicles. Results indicated that despite significant spatial variations in the expected severity of ice storms as a function of location, the distribution function for rates of accumulation were fairly similar and could be assumed to be independent of location. It was concluded that the observations from several sites could be combined in order to obtain better estimates of the distribution of hourly rates of ice accumulation. However, the rates were highly variable. For de-icing strategies, it was suggested that average accumulation rates over 12 hour periods were preferable, and that analyses should be performed for other time intervals to account for the variability in ice accumulation rates over time. In addition, accumulation rates did not appear to be highly correlated with average wind speed for maximum hourly accumulation rates. 3 refs., 2 tabs., 10 figs.

  19. Stochastic ice stream dynamics.

    Science.gov (United States)

    Mantelli, Elisa; Bertagni, Matteo Bernard; Ridolfi, Luca

    2016-08-09

    Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution.

  20. Sea Ice Ecosystems

    Science.gov (United States)

    Arrigo, Kevin R.

    2014-01-01

    Polar sea ice is one of the largest ecosystems on Earth. The liquid brine fraction of the ice matrix is home to a diverse array of organisms, ranging from tiny archaea to larger fish and invertebrates. These organisms can tolerate high brine salinity and low temperature but do best when conditions are milder. Thriving ice algal communities, generally dominated by diatoms, live at the ice/water interface and in recently flooded surface and interior layers, especially during spring, when temperatures begin to rise. Although protists dominate the sea ice biomass, heterotrophic bacteria are also abundant. The sea ice ecosystem provides food for a host of animals, with crustaceans being the most conspicuous. Uneaten organic matter from the ice sinks through the water column and feeds benthic ecosystems. As sea ice extent declines, ice algae likely contribute a shrinking fraction of the total amount of organic matter produced in polar waters.

  1. Ross Ice Shelf, Antarctic Ice and Clouds

    Science.gov (United States)

    1991-01-01

    In this view of Antarctic ice and clouds, (56.5S, 152.0W), the Ross Ice Shelf of Antarctica is almost totally clear, showing stress cracks in the ice surface caused by wind and tidal drift. Clouds on the eastern edge of the picture are associated with an Antarctic cyclone. Winds stirred up these storms have been known to reach hurricane force.

  2. A natural ice boom

    Energy Technology Data Exchange (ETDEWEB)

    Hopper, H.R. [Manitoba Hydro, Winnipeg, MB (Canada)

    1998-10-01

    Planning for ice jams and ice movements are critical on the Nelson River in northern Manitoba in designing cofferdams. Experience on the St. Lawrence River demonstrated the possibility of exercising some control over ice action by judicious placement of log booms or ice control structures. The success of experiments with man-made controls led to field tests in which an ice sheet of sufficient magnitude and competence was introduced into the open water stream of the Nelson River. The ice sheet was subsequently jammed in a narrow channel, thereby creating a natural ice bridge or boom upstream of a proposed hydro development. Under favourable conditions, this boom would initiate the progression of the ice cover from its location upstream, cutting off the downstream reach from the ice producing potential of the upstream reach. Although ice would still be generated downstream, the length of the reach between the ice boom and the development site would be short enough that ice jamming at the development site would never occur. Although problems in blasting prevented the introduction of a competent ice sheet into the main stream of the river at the location chosen, sufficient confidence in the theory was gained to warrant further consideration. 4 refs., 1 tab., 10 figs.

  3. ‘Fragile old man’: Mexico and France save a 2000-year-old sculpture using nuclear techniques

    International Nuclear Information System (INIS)

    Dixit, Aabha

    2015-01-01

    During an excavation in 2001 in Becán, a Maya civilization site located in Campeche State in south-eastern Mexico, a 2000-year-old wooden sculpture was unearthed causing a buzz in Mexico’s archaeological community. The wooden statue was tucked away deep beneath a collapsed tomb. It was the first ever wooden object found that could be reliably dated to the early classical Mayan period, but was slowly decaying, with many fragments broken off. With the help of nuclear technology, and assistance from France, scientists have revived it to its previous glory. The statue is now on display at the Campeche museum, along with other objects of Mayan art.

  4. Surface enhanced Raman spectroscopy and structural characterization of Ag/Cu chiral nano-flower sculptured thin films

    International Nuclear Information System (INIS)

    Savaloni, Hadi; Babaei, Reza

    2013-01-01

    Silver chiral nano-flower sculptured thin films with 3-, 4- and 5-fold symmetry were produced on copper substrates using oblique angle deposition method in conjunction with rotation of sample holder with different speeds at different sectors of each revolution corresponding to symmetry order of the acquired nano-flower. Atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) were employed to obtain morphologies and nano-structure of the films. Raman spectroscopy was performed on all samples that were subject to impregnation by 4,4′-bipyridine (C 10 H 8 N 2 ) solution. A high degree of enhancement of the main bands at 1610, 1297, and 1009 cm −1 that can be assigned to the C=C stretching mode, aromatic ring stretching ring and in-plane ring mode of 4,4′-bipyridine, is achieved.

  5. Surface enhanced Raman spectroscopy and structural characterization of Ag/Cu chiral nano-flower sculptured thin films

    Energy Technology Data Exchange (ETDEWEB)

    Savaloni, Hadi, E-mail: savaloni@khayam.ut.ac.ir [Department of Physics, University of Tehran, North-Kargar Street, Tehran (Iran, Islamic Republic of); Babaei, Reza, E-mail: reza_babaee_62@yahoo.com [Department of Physics, Islamic Azad University, Science and Research Branch, Tehran (Iran, Islamic Republic of)

    2013-09-01

    Silver chiral nano-flower sculptured thin films with 3-, 4- and 5-fold symmetry were produced on copper substrates using oblique angle deposition method in conjunction with rotation of sample holder with different speeds at different sectors of each revolution corresponding to symmetry order of the acquired nano-flower. Atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) were employed to obtain morphologies and nano-structure of the films. Raman spectroscopy was performed on all samples that were subject to impregnation by 4,4′-bipyridine (C{sub 10}H{sub 8}N{sub 2}) solution. A high degree of enhancement of the main bands at 1610, 1297, and 1009 cm{sup −1} that can be assigned to the C=C stretching mode, aromatic ring stretching ring and in-plane ring mode of 4,4′-bipyridine, is achieved.

  6. Forecast Icing Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Forecast Icing Product (FIP) is an automatically-generated index suitable for depicting areas of potentially hazardous airframe icing. The FIP algorithm uses...

  7. Current Icing Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Current Icing Product (CIP) is an automatically-generated index suitable for depicting areas of potentially hazardous airframe icing. The CIP algorithm combines...

  8. Sputtering of water ice

    International Nuclear Information System (INIS)

    Baragiola, R.A.; Vidal, R.A.; Svendsen, W.; Schou, J.; Shi, M.; Bahr, D.A.; Atteberrry, C.L.

    2003-01-01

    We present results of a range of experiments of sputtering of water ice together with a guide to the literature. We studied how sputtering depends on the projectile energy and fluence, ice growth temperature, irradiation temperature and external electric fields. We observed luminescence from the decay of H(2p) atoms sputtered by heavy ion impact, but not bulk ice luminescence. Radiolyzed ice does not sputter under 3.7 eV laser irradiation

  9. Helicopter Icing Review.

    Science.gov (United States)

    1980-09-01

    helicopter (i.e. in an icing tunnel or engine test cell ) and therefore can be subjected to controlled icing where spe- cific problems can be safely...evaluation. 69 2.2.5.2 Ice Protection Systems Demonstration Many of the systems noted in 2.2.5.1 can be evaluated in icing test cells or icing wind tunnels...Figure 2-32 illustrates a typical rotor deice system control arrangement. 104 (N >4 A.dO INaH -E- C4) uo U En 9 E-1 H m I ~z O 04 04iH U 0 El4 E-f C E

  10. Ice slurry applications

    Energy Technology Data Exchange (ETDEWEB)

    Kauffeld, M. [Karlsruhe University of Applied Sciences, Moltkestr. 30, 76133 Karlsruhe (Germany); Wang, M.J.; Goldstein, V. [Sunwell Technologies Inc., 180 Caster Avenue, Woodbridge, L4L 5Y (Canada); Kasza, K.E. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2010-12-15

    The role of secondary refrigerants is expected to grow as the focus on the reduction of greenhouse gas emissions increases. The effectiveness of secondary refrigerants can be improved when phase changing media are introduced in place of single-phase media. Operating at temperatures below the freezing point of water, ice slurry facilitates several efficiency improvements such as reductions in pumping energy consumption as well as lowering the required temperature difference in heat exchangers due to the beneficial thermo-physical properties of ice slurry. Research has shown that ice slurry can be engineered to have ideal ice particle characteristics so that it can be easily stored in tanks without agglomeration and then be extractable for pumping at very high ice fraction without plugging. In addition ice slurry can be used in many direct contact food and medical protective cooling applications. This paper provides an overview of the latest developments in ice slurry technology. (author)

  11. Autonomous Aerial Ice Observation for Ice Defense

    Directory of Open Access Journals (Sweden)

    Joakim Haugen

    2014-10-01

    Full Text Available One of the tasks in ice defense is to gather information about the surrounding ice environment using various sensor platforms. In this manuscript we identify two monitoring tasks known in literature, namely dynamic coverage and target tracking, and motivate how these tasks are relevant in ice defense using RPAS. An optimization-based path planning concept is outlined for solving these tasks. A path planner for the target tracking problem is elaborated in more detail and a hybrid experiment, which consists of both a real fixed-wing aircraft and simulated objects, is included to show the applicability of the proposed framework.

  12. Arctic landfast sea ice

    Science.gov (United States)

    Konig, Christof S.

    Landfast ice is sea ice which forms and remains fixed along a coast, where it is attached either to the shore, or held between shoals or grounded icebergs. Landfast ice fundamentally modifies the momentum exchange between atmosphere and ocean, as compared to pack ice. It thus affects the heat and freshwater exchange between air and ocean and impacts on the location of ocean upwelling and downwelling zones. Further, the landfast ice edge is essential for numerous Arctic mammals and Inupiat who depend on them for their subsistence. The current generation of sea ice models is not capable of reproducing certain aspects of landfast ice formation, maintenance, and disintegration even when the spatial resolution would be sufficient to resolve such features. In my work I develop a new ice model that permits the existence of landfast sea ice even in the presence of offshore winds, as is observed in mature. Based on viscous-plastic as well as elastic-viscous-plastic ice dynamics I add tensile strength to the ice rheology and re-derive the equations as well as numerical methods to solve them. Through numerical experiments on simplified domains, the effects of those changes are demonstrated. It is found that the modifications enable landfast ice modeling, as desired. The elastic-viscous-plastic rheology leads to initial velocity fluctuations within the landfast ice that weaken the ice sheet and break it up much faster than theoretically predicted. Solving the viscous-plastic rheology using an implicit numerical method avoids those waves and comes much closer to theoretical predictions. Improvements in landfast ice modeling can only verified in comparison to observed data. I have extracted landfast sea ice data of several decades from several sources to create a landfast sea ice climatology that can be used for that purpose. Statistical analysis of the data shows several factors that significantly influence landfast ice distribution: distance from the coastline, ocean depth, as

  13. Her Excellency Mrs Sarah Gillett Her Majesty's Ambassador to the Swiss Confederation United Kingdom of Great Britain and Northern Ireland on the occasion of the Antony Gormley sculpture unveiling ceremony Wednesday 7th December 2011

    CERN Document Server

    Maximilien Brice

    2011-01-01

    Her Excellency Mrs Sarah Gillett Her Majesty's Ambassador to the Swiss Confederation United Kingdom of Great Britain and Northern Ireland on the occasion of the Antony Gormley sculpture unveiling ceremony Wednesday 7th December 2011

  14. Removable cruciform for ice condenser ice basket

    International Nuclear Information System (INIS)

    Scrabis, C.M.; Mazza, G.E.; Golick, L.R.; Pomaibo, P.

    1987-01-01

    A removable cruciform for use in an ice basket having a generally cylindrical sidewall defining a central, vertical axis of the ice basket and plural, generally annular retaining rings secured to the interior of the cylindrical sidewall of the ice basket at predetermined, spaced elevations throughout the axial height of the ice basket is described comprising: a pair of brackets, each comprising a central, base portion having parallel longitudinal edges and a pair of integral legs extending at corresponding angles relative to the base portion from the perspective parallel longitudinal edges thereof; a pair of support plate assemblies secured to and extending in parallel, spaced relationship from one of the pair of brackets; a pair of slide support plates secured to the other of the pair of brackets and extending therefrom in spaced, parallel relationship; and spring means received within the housing and engaging the base portions of the brackets and applying a resilient biasing force thereto for maintaining the spaced relationship thereof

  15. Ice cream structure modification by ice-binding proteins.

    Science.gov (United States)

    Kaleda, Aleksei; Tsanev, Robert; Klesment, Tiina; Vilu, Raivo; Laos, Katrin

    2018-04-25

    Ice-binding proteins (IBPs), also known as antifreeze proteins, were added to ice cream to investigate their effect on structure and texture. Ice recrystallization inhibition was assessed in the ice cream mixes using a novel accelerated microscope assay and the ice cream microstructure was studied using an ice crystal dispersion method. It was found that adding recombinantly produced fish type III IBPs at a concentration 3 mg·L -1 made ice cream hard and crystalline with improved shape preservation during melting. Ice creams made with IBPs (both from winter rye, and type III IBP) had aggregates of ice crystals that entrapped pockets of the ice cream mixture in a rigid network. Larger individual ice crystals and no entrapment in control ice creams was observed. Based on these results a model of ice crystals aggregates formation in the presence of IBPs was proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. EDXRF portable system used in the analysis of altars, sculptures and paintings from XVII and XVIII centuries in Brazil

    International Nuclear Information System (INIS)

    Freitas, R.P.; Calza, C.; Lopes, R.T.; Santos, R.O.

    2011-01-01

    Full text: The preservation of cultural heritage has acquired increasing interest in the last decades and many scientific techniques have been employed to analyze paintings, manuscripts, ceramics, glasses, statues, coins and metal artifacts in order to solve problems related to restoration, conservation, dating and attribution of artworks. There is also an increasing trend for non-destructive investigations since most of the samples are unique and precious objects of art and archaeology. X-Ray fluorescence (XRF) is the most widely used investigative technique in the field of archaeometry, due to a number of favorable analytical characteristics, such as multielemental and non-destructive analysis, high sensitivity and applicability to a wide range of samples. In this work, XRF was used to analyze altars, sculptures and paintings in the Saint Anthony Convent (Rio de Janeiro, Brazil). The cornerstone of this convent was launched in 1608, by the Franciscan friars, and the construction of the church was finished in 1620. The Saint Anthony sculpture in the main altar is one of the few remaining pieces from the XVII century in Rio de Janeiro. The splendid Baroque carvings of the chapel, covered with integral gilding, in the national Portuguese style, dates from 1716 to 1719. The results obtained during the analyses have been used in the meticulous process of restoration, developed in the last two years, in order to recover the original splendour of this important piece of our cultural heritage. The analyses were carried out with an EDXRF portable system developed in the Nuclear Instrumentation Laboratory, consisting of an X-ray tube Oxford TF3005 with W anode, operating at 25 kV and 100 μA, and a Si-PIN XR-100CR detector from Amptek. In each sample were obtained several spectra, with an acquisition time of 300 s and a beam collimation of 1.5 and 2 mm. The spectra were analyzed using the software QXAS-AXIL from IAEA. The analysis of the golden carvings of the altars, in

  17. Aircraft Icing Handbook. (Update)

    Science.gov (United States)

    1993-01-01

    Report 1946-1947, U. S. Air Material Command Tech. Rept. 5676. Findeisen , W., *Meteorological Commentary of D (air) 1209, Icing,* Germany, Reichsamt fur...Wetterdienst, Forschungs-und Krfahrungsberichte, Ser. a, No. 29, 1943. Findeisen , W., *Meteorological-Physical Limitations of Icing on the Atmosphere...Apparatus for Measurement,’ Harvard - Mt. Washington Icing Research Report 1946-1947, U. S. Air Material Command Tech. Rept. 5676.. Findeisen , W., "The

  18. Safe Loads on Ice Sheets (Ice Engineering. Number 13)

    National Research Council Canada - National Science Library

    Haynes, F. D; Carey, Kevin L; Cattabriga, Gioia

    1996-01-01

    Every winter, ice sheets that grow on lakes and rivers in northern states are used for ice roads, ice bridges, construction platforms, airstrips, and recreational activities, It becomes very important...

  19. Data-Driven Analysis of Virtual 3D Exploration of a Large Sculpture Collection in Real-World Museum Exhibitions

    KAUST Repository

    Agus, Marco

    2018-01-29

    We analyze use of an interactive system for the exploration of highly detailed three-dimensional (3D) models of a collection of protostoric Mediterranean sculptures. In this system, when the object of interest is selected, its detailed 3D model and associated information are presented at high resolution on a large display controlled by a touch-enabled horizontal surface at a suitable distance. The user interface combines an object-Aware interactive camera controller with an interactive point-ofinterest selector and is implemented within a scalable implementation based on multiresolution structures shared between the rendering and user interaction subsystems. The system was installed in several temporary and permanent exhibitions and was extensively used by tens of thousands of visitors. We provide a data-driven analysis of usage experience based on logs gathered during a 27-month period at four exhibitions in archeological museums for a total of more than 75K exploration sessions. We focus on discerning the main visitor behaviors during 3D exploration by employing tools for deriving interest measures on surfaces and tools for clustering and knowledge discovery from high-dimensional data. The results highlight the main trends in visitor behavior during the interactive sessions. These results provide useful insights for the design of 3D exploration user interfaces in future digital installations.© 2017 ACM 1556-4673/2017/12-ART2 $15.00.

  20. “TEMPORIBUS DOMINI IOHANNIS EPISCOPI...” – On the Beginnings of Pre-Romanesque Sculpture in Boka Kotorska

    Directory of Open Access Journals (Sweden)

    Meri Zornija

    2016-01-01

    Full Text Available This paper focuses on a series of pre-Romanesque fragments found in Kotor and several other localities in Boka Kotorska, which can be linked to an early phase in the formation of the pre-Romanesque style. Chronological orientation points provided by the triple mention of Bishop Ivan, who was present at the Second Council of Nicaea in 787, have served as a framework dating the fragments to the last quarter of the 8th and the early 9th century. They are considered to be work of a highly skilful stonemason workshop, for which the name Stonemason Workshop from the Time of Bishop Ivan of Kotor has been proposed. The reliefs have been compared to analogous sculptural decoration adorning the cathedrals of other cities in the Eastern Adriatic based on similar stylistic and iconographic features,as well as masterful stonemasonry in high-quality marble. These analogies indicate a common visual language used by the masters active in the broad belt stretching from Istria to Boka Kotorska, who brought to our coast the spirit of new, pre-Romanesque art at the turn of the 9th century.

  1. Data-Driven Analysis of Virtual 3D Exploration of a Large Sculpture Collection in Real-World Museum Exhibitions

    KAUST Repository

    Agus, Marco; Marton, Fabio; Bettio, Fabio; Hadwiger, Markus; Gobbetti, Enrico

    2018-01-01

    We analyze use of an interactive system for the exploration of highly detailed three-dimensional (3D) models of a collection of protostoric Mediterranean sculptures. In this system, when the object of interest is selected, its detailed 3D model and associated information are presented at high resolution on a large display controlled by a touch-enabled horizontal surface at a suitable distance. The user interface combines an object-Aware interactive camera controller with an interactive point-ofinterest selector and is implemented within a scalable implementation based on multiresolution structures shared between the rendering and user interaction subsystems. The system was installed in several temporary and permanent exhibitions and was extensively used by tens of thousands of visitors. We provide a data-driven analysis of usage experience based on logs gathered during a 27-month period at four exhibitions in archeological museums for a total of more than 75K exploration sessions. We focus on discerning the main visitor behaviors during 3D exploration by employing tools for deriving interest measures on surfaces and tools for clustering and knowledge discovery from high-dimensional data. The results highlight the main trends in visitor behavior during the interactive sessions. These results provide useful insights for the design of 3D exploration user interfaces in future digital installations.© 2017 ACM 1556-4673/2017/12-ART2 $15.00.

  2. Ice and ocean velocity in the Arctic marginal ice zone: Ice roughness and momentum transfer

    Directory of Open Access Journals (Sweden)

    Sylvia T. Cole

    2017-09-01

    Full Text Available The interplay between sea ice concentration, sea ice roughness, ocean stratification, and momentum transfer to the ice and ocean is subject to seasonal and decadal variations that are crucial to understanding the present and future air-ice-ocean system in the Arctic. In this study, continuous observations in the Canada Basin from March through December 2014 were used to investigate spatial differences and temporal changes in under-ice roughness and momentum transfer as the ice cover evolved seasonally. Observations of wind, ice, and ocean properties from four clusters of drifting instrument systems were complemented by direct drill-hole measurements and instrumented overhead flights by NASA operation IceBridge in March, as well as satellite remote sensing imagery about the instrument clusters. Spatially, directly estimated ice-ocean drag coefficients varied by a factor of three with rougher ice associated with smaller multi-year ice floe sizes embedded within the first-year-ice/multi-year-ice conglomerate. Temporal differences in the ice-ocean drag coefficient of 20–30% were observed prior to the mixed layer shoaling in summer and were associated with ice concentrations falling below 100%. The ice-ocean drag coefficient parameterization was found to be invalid in September with low ice concentrations and small ice floe sizes. Maximum momentum transfer to the ice occurred for moderate ice concentrations, and transfer to the ocean for the lowest ice concentrations and shallowest stratification. Wind work and ocean work on the ice were the dominant terms in the kinetic energy budget of the ice throughout the melt season, consistent with free drift conditions. Overall, ice topography, ice concentration, and the shallow summer mixed layer all influenced mixed layer currents and the transfer of momentum within the air-ice-ocean system. The observed changes in momentum transfer show that care must be taken to determine appropriate parameterizations

  3. Bacterial Ice Crystal Controlling Proteins

    Science.gov (United States)

    Lorv, Janet S. H.; Rose, David R.; Glick, Bernard R.

    2014-01-01

    Across the world, many ice active bacteria utilize ice crystal controlling proteins for aid in freezing tolerance at subzero temperatures. Ice crystal controlling proteins include both antifreeze and ice nucleation proteins. Antifreeze proteins minimize freezing damage by inhibiting growth of large ice crystals, while ice nucleation proteins induce formation of embryonic ice crystals. Although both protein classes have differing functions, these proteins use the same ice binding mechanisms. Rather than direct binding, it is probable that these protein classes create an ice surface prior to ice crystal surface adsorption. Function is differentiated by molecular size of the protein. This paper reviews the similar and different aspects of bacterial antifreeze and ice nucleation proteins, the role of these proteins in freezing tolerance, prevalence of these proteins in psychrophiles, and current mechanisms of protein-ice interactions. PMID:24579057

  4. Sputtering of water ice

    DEFF Research Database (Denmark)

    Baragiola, R.A.; Vidal, R.A.; Svendsen, W.

    2003-01-01

    We present results of a range of experiments of sputtering of water ice together with a guide to the literature. We studied how sputtering depends on the projectile energy and fluence, ice growth temperature, irradiation temperature and external electric fields. We observed luminescence from...

  5. Ice sheet in peril

    DEFF Research Database (Denmark)

    Hvidberg, Christine Schøtt

    2016-01-01

    Earth's large ice sheets in Greenland and Antarctica are major contributors to sea level change. At present, the Greenland Ice Sheet (see the photo) is losing mass in response to climate warming in Greenland (1), but the present changes also include a long-term response to past climate transitions...

  6. Turning into Ice

    Science.gov (United States)

    Pietsch, Renée B.; Hanlon, Regina; Bohland, Cynthia; Schmale, David G., III

    2016-01-01

    This article describes an interdisciplinary unit in which students explore biological "ice nucleation"--by particles that cause water to freeze at temperatures above -38°C--through the lens of the microbial ice nucleator "Pseudomonas syringae." Such This activity, which aligns with the "Next Generation Science…

  7. GLERL Radiation Transfer Through Freshwater Ice

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Radiation transmittance (ratio of transmitted to incident radiation) through clear ice, refrozen slush ice and brash ice, from ice surface to ice-water interface in...

  8. Torque and Axial Loading Physics for Measuring Atmospheric Icing Load and Icing Rate

    OpenAIRE

    Mughal, Umair Najeeb; Virk, Muhammad Shakeel

    2015-01-01

    Measuring icing load and icing rate are important parameters for an atmospheric icing sensor. A new icing sensor has recently been designed and developed at Narvik University College for measuring atmospheric icing rate, icing load and icing type. Unlike the existing atmospheric icing sensors commercially available in market, which uses the axial loading for measuring icing load and icing rate, this new sensory system measures icing load and icing rate using the torque loading physics. The pe...

  9. Modelling snow ice and superimposed ice on landfast sea ice in Kongsfjorden, Svalbard

    Directory of Open Access Journals (Sweden)

    Caixin Wang

    2015-08-01

    Full Text Available Snow ice and superimposed ice formation on landfast sea ice in a Svalbard fjord, Kongsfjorden, was investigated with a high-resolution thermodynamic snow and sea-ice model, applying meteorological weather station data as external forcing. The model shows that sea-ice formation occurs both at the ice bottom and at the snow/ice interface. Modelling results indicated that the total snow ice and superimposed ice, which formed at the snow/ice interface, was about 14 cm during the simulation period, accounting for about 15% of the total ice mass and 35% of the total ice growth. Introducing a time-dependent snow density improved the modelled results, and a time-dependent oceanic heat flux parameterization yielded reasonable ice growth at the ice bottom. Model results suggest that weather conditions, in particular air temperature and precipitation, as well as snow thermal properties and surface albedo are the most critical factors for the development of snow ice and superimposed ice in Kongsfjorden. While both warming air and higher precipitation led to increased snow ice and superimposed ice forming in Kongsfjorden in the model runs, the processes were more sensitive to precipitation than to air temperature.

  10. Coulombic charge ice

    Science.gov (United States)

    McClarty, P. A.; O'Brien, A.; Pollmann, F.

    2014-05-01

    We consider a classical model of charges ±q on a pyrochlore lattice in the presence of long-range Coulomb interactions. This model first appeared in the early literature on charge order in magnetite [P. W. Anderson, Phys. Rev. 102, 1008 (1956), 10.1103/PhysRev.102.1008]. In the limit where the interactions become short ranged, the model has a ground state with an extensive entropy and dipolar charge-charge correlations. When long-range interactions are introduced, the exact degeneracy is broken. We study the thermodynamics of the model and show the presence of a correlated charge liquid within a temperature window in which the physics is well described as a liquid of screened charged defects. The structure factor in this phase, which has smeared pinch points at the reciprocal lattice points, may be used to detect charge ice experimentally. In addition, the model exhibits fractionally charged excitations ±q/2 which are shown to interact via a 1/r potential. At lower temperatures, the model exhibits a transition to a long-range ordered phase. We are able to treat the Coulombic charge ice model and the dipolar spin ice model on an equal footing by mapping both to a constrained charge model on the diamond lattice. We find that states of the two ice models are related by a staggering field which is reflected in the energetics of these two models. From this perspective, we can understand the origin of the spin ice and charge ice ground states as coming from a dipolar model on a diamond lattice. We study the properties of charge ice in an external electric field, finding that the correlated liquid is robust to the presence of a field in contrast to the case of spin ice in a magnetic field. Finally, we comment on the transport properties of Coulombic charge ice in the correlated liquid phase.

  11. Creep of ice: further studies

    International Nuclear Information System (INIS)

    Heard, H.C.; Durham, W.B.; Kirby, S.H.

    1987-01-01

    Detailed studies have been done of ice creep as related to the icy satellites, Ganymede and Callisto. Included were: (1) the flow of high-pressure water ices II, III, and V, and (2) frictional sliding of ice I sub h. Work was also begun on the study of the effects of impurities on the flow of ice. Test results are summarized

  12. Vortex ice in nanostructured superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Reichhardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia J [Los Alamos National Laboratory; Libal, Andras J [Los Alamos National Laboratory

    2008-01-01

    We demonstrate using numerical simulations of nanostructured superconductors that it is possible to realize vortex ice states that are analogous to square and kagome ice. The system can be brought into a state that obeys either global or local ice rules by applying an external current according to an annealing protocol. We explore the breakdown of the ice rules due to disorder in the nanostructure array and show that in square ice, topological defects appear along grain boundaries, while in kagome ice, individual defects appear. We argue that the vortex system offers significant advantages over other artificial ice systems.

  13. The fabrication and hydrophobic property of micro-nano patterned surface on magnesium alloy using combined sparking sculpture and etching route

    Science.gov (United States)

    Wu, Yunfeng; Wang, Yaming; Liu, Hao; Liu, Yan; Guo, Lixin; Jia, Dechang; Ouyang, Jiahu; Zhou, Yu

    2016-12-01

    Magnesium alloy with micro-nano structure roughness surface, can serve as the loading reservoirs of medicine capsule and industrial lubricating oil, or mimic 'lotus leaf' hydrophobic surface, having the potential applications in medical implants, automobile, aerospace and electronic products, etc. Herein, we propose a novel strategy to design a micro-nano structure roughness surface on magnesium alloy using combined microarc sparking sculpture and etching in CrO3 aqueous solution. A hydrophobic surface (as an applied example) was further fabricated by chemical decorating on the obtained patterned magnesium alloy surface to enhance the corrosion resistance. The results show that the combined micro-nano structure of 7-9 μm diameter big pores insetting with nano-scale fine pores was duplicated after etched the sparking sculptured 'over growth' oxide regions towards the magnesium substrate. The micro-nano structure surface was chemically decorated using AgNO3 and stearic acid, which enables the contact angle increased from 60° to 146.8°. The increasing contact angle is mainly attributed to the micro-nano structure and the chemical composition. The hydrophobic surface of magnesium alloy improved the corrosion potential from -1.521 V of the bare magnesium to -1.274 V. Generally, the sparking sculpture and then etching route demonstrates a low-cost, high-efficacy method to fabricate a micro-nano structure hydrophobic surface on magnesium alloy. Furthermore, our research on the creating of micro-nano structure roughness surface and the hydrophobic treatment can be easily extended to the other metal materials.

  14. Ice Engineering Research Area

    Data.gov (United States)

    Federal Laboratory Consortium — Refrigerated Physical Modeling of Waterways in a Controlled EnvironmentThe Research Area in the Ice Engineering Facility at the Cold Regions Research and Engineering...

  15. Ice Cream Stick Math.

    Science.gov (United States)

    Paddock, Cynthia

    1992-01-01

    Described is a teaching technique which uses the collection of ice cream sticks as a means of increasing awareness of quantity in a self-contained elementary special class for students with learning disabilities and mild mental retardation. (DB)

  16. Global ice sheet modeling

    International Nuclear Information System (INIS)

    Hughes, T.J.; Fastook, J.L.

    1994-05-01

    The University of Maine conducted this study for Pacific Northwest Laboratory (PNL) as part of a global climate modeling task for site characterization of the potential nuclear waste respository site at Yucca Mountain, NV. The purpose of the study was to develop a global ice sheet dynamics model that will forecast the three-dimensional configuration of global ice sheets for specific climate change scenarios. The objective of the third (final) year of the work was to produce ice sheet data for glaciation scenarios covering the next 100,000 years. This was accomplished using both the map-plane and flowband solutions of our time-dependent, finite-element gridpoint model. The theory and equations used to develop the ice sheet models are presented. Three future scenarios were simulated by the model and results are discussed

  17. Prosthetically guided bone sculpturing for a maxillary complete-arch implant-supported monolithic zirconia fixed prosthesis based on a digital smile design: A clinical report.

    Science.gov (United States)

    Rojas-Vizcaya, Fernando

    2017-11-01

    A digital smile design was used to create an average smile and to develop a removable interim restoration for an edentulous patient with a high smile line and different bone levels in the maxilla. The interim restoration was used as a guide to perform bone sculpturing to create space for the biological width and to restore a monolithic zirconia implant-supported fixed restoration. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  18. The Antartic Ice Borehole Probe

    Science.gov (United States)

    Behar, A.; Carsey, F.; Lane, A.; Engelhardt, H.

    2000-01-01

    The Antartic Ice Borehole Probe mission is a glaciological investigation, scheduled for November 2000-2001, that will place a probe in a hot-water drilled hole in the West Antartic ice sheet. The objectives of the probe are to observe ice-bed interactions with a downward looking camera, and ice inclusions and structure, including hypothesized ice accretion, with a side-looking camera.

  19. Ice recrystallization inhibition in ice cream by propylene glycol monostearate.

    Science.gov (United States)

    Aleong, J M; Frochot, S; Goff, H D

    2008-11-01

    The effectiveness of propylene glycol monostearate (PGMS) to inhibit ice recrystallization was evaluated in ice cream and frozen sucrose solutions. PGMS (0.3%) dramatically reduced ice crystal sizes in ice cream and in sucrose solutions frozen in a scraped-surface freezer before and after heat shock, but had no effect in quiescently frozen solutions. PGMS showed limited emulsifier properties by promoting smaller fat globule size distributions and enhanced partial coalescence in the mix and ice cream, respectively, but at a much lower level compared to conventional ice cream emulsifier. Low temperature scanning electron microscopy revealed highly irregular crystal morphology in both ice cream and sucrose solutions frozen in a scraped-surface freezer. There was strong evidence to suggest that PGMS directly interacts with ice crystals and interferes with normal surface propagation. Shear during freezing may be required for its distribution around the ice and sufficient surface coverage.

  20. Method for maintenance of ice beds of ice condenser containment

    International Nuclear Information System (INIS)

    Scrabis, C.M.; Hardin, R.T. Jr.

    1987-01-01

    This patent describes a method of maintaining ice baskets associated with a nuclear reactor system and disposed in an array of plural such ice baskets, supported in generally vertically oriented and parallel relationship by a lattice support structure which extends between the individual ice baskets and includes lateral supports adjacent the tops of the comprising: selecting an ice basket of the array requiring replenishment of the ice therewithin due to sublimation voids within the ice charges in the basket; isolating the selected ice basket; drilling a hole downwardly through the ice charges in the ice basket in general parallel axial relationship with respect to the cylindrical sidewall of the ice basket, utilizing a rotary drill bit connected through an auger to a rotary drive means; maintaining the rotary drive means in a fixed axial position and reversing the direction of rotation thereof for driving the auger in reverse rotation; and supplying ice in particulate form to the vicinity of the auger and conveying the particulate ice through the drilled hole by continued, reverse rotation of the auger so as to fill the sublimated voids in communication with the drilled hole, from the lowest and through successively higher such voids in the ice charges within the ice basket, and withdrawing the auger from the drilled hole as the voids are filled

  1. Icing losses on wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, T.; Fotsing, I.; Pearson, S. [Garrad Hassan Canada Inc., Ottawa, ON (Canada)

    2010-07-01

    This PowerPoint presentation discussed some of the energy losses that can occur as a result of icing on wind turbines. Airfoil deterioration can occur in the presence of rime and glaze ice. Anemometers are also impacted by ice, and shut-downs can occur as a result of icing events. Availability deficits that occur during the winter months can lead to annual energy losses of 0.5 percent. The impact of icing events on total wind power energy production in Quebec is estimated at between 1.3 percent to 2.7 percent. Ice loss estimates are considered during the pre-construction phases of wind power projects. However, ice loss prediction methods are often inaccurate. Studies have demonstrated that preconstruction masts show a reasonable correlation with wind turbine icing, and that icing losses are site-specific. tabs., figs.

  2. Ice flow Modelling of the Greenland Ice Sheet

    DEFF Research Database (Denmark)

    Nielsen, Lisbeth Tangaa

    Models of ice flow have a range of application in glaciology, including investigating the large-scale response of ice sheets to changes in climate, assimilating data to estimate unknown conditions beneath the ice sheet, and in interpreting proxy records obtained from ice cores, among others. In t...... a steady state with respect to the reference climate at the end of the simulation and that the mass balance of the ice sheet at this time was more sensitive to recent climate fluctuations than the temperature forcing in the early or mid-Holocene.......Models of ice flow have a range of application in glaciology, including investigating the large-scale response of ice sheets to changes in climate, assimilating data to estimate unknown conditions beneath the ice sheet, and in interpreting proxy records obtained from ice cores, among others....... In this PhD project, the use of ice flow models for the interpretation of the age-structure of the Greenland ice sheet, i.e. the depth within the ice, at which ice deposited at given times are found at present day. Two different observational data sets of this archive were investigated. Further, paleo...

  3. Elucidation of molecular and elementary composition of organic and inorganic substances involved in 19th century wax sculptures using an integrated analytical approach

    International Nuclear Information System (INIS)

    Regert, M.; Langlois, J.; Laval, E.; Le Ho, A.-S.; Pages-Camagna, S.

    2006-01-01

    Wax sculptures contain several materials from both organic and inorganic nature. These works of art are particularly fragile. Determining their chemical composition is thus of prime importance for their preservation. The identification of the recipes of waxy pastes used through time also provides valuable information in the field of art history. The aim of the present research was to develop a convenient analytical strategy, as non-invasive as possible, that allows to identify the wide range of materials involved in wax sculptures. A multi-step analytical methodology, based on the use of complementary techniques, either non- or micro-destructive, was elaborated. X-ray fluorescence and micro-Raman spectroscopy were used in a non-invasive way to identify inorganic pigments, opacifiers and extenders. The combination of structural and separative techniques, namely infrared spectroscopy, direct inlet electron ionisation mass spectrometry and high temperature gas chromatography, was shown to be appropriate for unravelling the precise composition of the organic substances. A micro-chemical test was also performed for the detection of starch. From this study it has been possible to elucidate the composition of the waxy pastes used by three different sculptors at the end of the 19th century. Complex and elaborated recipes, in which a large range of natural substances were combined, were highlighted

  4. XRF, μ-XRD and μ-spectroscopic techniques for revealing the composition and structure of paint layers on polychrome sculptures after multiple restorations.

    Science.gov (United States)

    Franquelo, M L; Duran, A; Castaing, J; Arquillo, D; Perez-Rodriguez, J L

    2012-01-30

    This paper presents the novel application of recently developed analytical techniques to the study of paint layers on sculptures that have been restored/repainted several times across centuries. Analyses were performed using portable XRF, μ-XRD and μ-Raman instruments. Other techniques, such as optical microscopy, SEM-EDX and μ-FTIR, were also used. Pigments and other materials including vermilion, minium, red lac, ivory black, lead white, barium white, zinc white (zincite), titanium white (rutile and anatase), lithopone, gold and brass were detected. Pigments from both ancient and modern times were found due to the different restorations/repaintings carried out. μ-Raman was very useful to characterise some pigments that were difficult to determine by μ-XRD. In some cases, pigments identification was only possible by combining results from the different analytical techniques used in this work. This work is the first article devoted to the study of sculpture cross-section samples using laboratory-made μ-XRD systems. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Modeling Commercial Turbofan Engine Icing Risk With Ice Crystal Ingestion

    Science.gov (United States)

    Jorgenson, Philip C. E.; Veres, Joseph P.

    2013-01-01

    The occurrence of ice accretion within commercial high bypass aircraft turbine engines has been reported under certain atmospheric conditions. Engine anomalies have taken place at high altitudes that have been attributed to ice crystal ingestion, partially melting, and ice accretion on the compression system components. The result was degraded engine performance, and one or more of the following: loss of thrust control (roll back), compressor surge or stall, and flameout of the combustor. As ice crystals are ingested into the fan and low pressure compression system, the increase in air temperature causes a portion of the ice crystals to melt. It is hypothesized that this allows the ice-water mixture to cover the metal surfaces of the compressor stationary components which leads to ice accretion through evaporative cooling. Ice accretion causes a blockage which subsequently results in the deterioration in performance of the compressor and engine. The focus of this research is to apply an engine icing computational tool to simulate the flow through a turbofan engine and assess the risk of ice accretion. The tool is comprised of an engine system thermodynamic cycle code, a compressor flow analysis code, and an ice particle melt code that has the capability of determining the rate of sublimation, melting, and evaporation through the compressor flow path, without modeling the actual ice accretion. A commercial turbofan engine which has previously experienced icing events during operation in a high altitude ice crystal environment has been tested in the Propulsion Systems Laboratory (PSL) altitude test facility at NASA Glenn Research Center. The PSL has the capability to produce a continuous ice cloud which are ingested by the engine during operation over a range of altitude conditions. The PSL test results confirmed that there was ice accretion in the engine due to ice crystal ingestion, at the same simulated altitude operating conditions as experienced previously in

  6. The ICES system

    International Nuclear Information System (INIS)

    Inzaghi, A.

    1983-01-01

    ICES is an integrated system used in the various engineering fields. It is made up of the Basic System and the applied Subsystems. ICES is controlled by the Operating System of the computer, from which it calls for suitable services: space allocation, loading of the modules etc... To be able to use software of this type on a computer the Operating System should be made more general. The Subsystems are developed with special programs included in the ICES Basic System. Each Subsystem is associated with an area of application. In other words, a Subsystem can only treat a previously defined ''class of problems''. The engineer (user) communicates with the Subsystem using a language oriented towards the problem (POL) also previously defined using the CDL language. The use of the (POL) language makes the engineer-computer contact much easier. The applied programs written in ICETRAN, once supplied as input to the ICETRAN Precompiler, become Fortran programs with special characteristics. A Fortran compiler produces the corresponding object programs with which, using the ICES ''Link-edit'' procedures, one obtains the modules which can be executed by an ICES Subsystem

  7. Ice Engineering. Number 25, September 2000. Remote Ice Motion Detection

    National Research Council Canada - National Science Library

    2000-01-01

    .... Government agencies, and the engineering community in general. The potential exists for property damage, serious injury, and fatalities during ice-related flooding, evacuations, and other ice mitigation operations...

  8. Architecture or Sculpture?

    DEFF Research Database (Denmark)

    Baumeister, Ruth

    2014-01-01

    Jørn Utzon´s museum design for Asger Jorn´s collection in Silkeborg contextualized in the postwar context of an organic architecture.......Jørn Utzon´s museum design for Asger Jorn´s collection in Silkeborg contextualized in the postwar context of an organic architecture....

  9. On the Ice Nucleation Spectrum

    Science.gov (United States)

    Barahona, D.

    2012-01-01

    This work presents a novel formulation of the ice nucleation spectrum, i.e. the function relating the ice crystal concentration to cloud formation conditions and aerosol properties. The new formulation is physically-based and explicitly accounts for the dependency of the ice crystal concentration on temperature, supersaturation, cooling rate, and particle size, surface area and composition. This is achieved by introducing the concepts of ice nucleation coefficient (the number of ice germs present in a particle) and nucleation probability dispersion function (the distribution of ice nucleation coefficients within the aerosol population). The new formulation is used to generate ice nucleation parameterizations for the homogeneous freezing of cloud droplets and the heterogeneous deposition ice nucleation on dust and soot ice nuclei. For homogeneous freezing, it was found that by increasing the dispersion in the droplet volume distribution the fraction of supercooled droplets in the population increases. For heterogeneous ice nucleation the new formulation consistently describes singular and stochastic behavior within a single framework. Using a fundamentally stochastic approach, both cooling rate independence and constancy of the ice nucleation fraction over time, features typically associated with singular behavior, were reproduced. Analysis of the temporal dependency of the ice nucleation spectrum suggested that experimental methods that measure the ice nucleation fraction over few seconds would tend to underestimate the ice nuclei concentration. It is shown that inferring the aerosol heterogeneous ice nucleation properties from measurements of the onset supersaturation and temperature may carry significant error as the variability in ice nucleation properties within the aerosol population is not accounted for. This work provides a simple and rigorous ice nucleation framework where theoretical predictions, laboratory measurements and field campaign data can be

  10. Rheology of planetary ices

    Energy Technology Data Exchange (ETDEWEB)

    Durham, W.B. [Lawrence Livermore National Lab., CA (United States); Kirby, S.H.; Stern, L.A. [Geological Survey, Menlo Park, CA (United States)

    1996-04-24

    The brittle and ductile rheology of ices of water, ammonia, methane, and other volatiles, in combination with rock particles and each other, have a primary influence of the evolution and ongoing tectonics of icy moons of the outer solar system. Laboratory experiments help constrain the rheology of solar system ices. Standard experimental techniques can be used because the physical conditions under which most solar system ices exist are within reach of conventional rock mechanics testing machines, adapted to the low subsolidus temperatures of the materials in question. The purpose of this review is to summarize the results of a decade-long experimental deformation program and to provide some background in deformation physics in order to lend some appreciation to the application of these measurements to the planetary setting.

  11. Ice accreditation vs wind

    Energy Technology Data Exchange (ETDEWEB)

    Sabourin, G. [Hydro-Quebec, PQ (Canada). TransEnergie Div.; Chouinard, L. [McGill Univ., Montreal, PQ (Canada); Feknous, N. [SNC-Lavalin, Montreal, PQ (Canada)

    2002-07-01

    Wind and ice data from Hydro Quebec and Environment Canada indicates that winds during ice storms are in the general direction of the St. Lawrence River. This observation is important for upgrading existing power transmission lines from the Manicouagan and Churchill generation system because they are parallel to the St. Lawrence and they were designed with lower criteria than is currently accepted. ASCE 74 suggests an accumulation ratio based on thickness of 0.70 for winds parallel to the line. The Goodwin model was used to calculate this ratio. The presentation includes illustrations showing the accumulation ratio for a north wind, as well as the accumulation ratios and wind roses at Quebec. A table showing a comparison of ratios from passive ice meters shows that results are similar to mean values from the theoretical model.

  12. Ice cores and palaeoclimate

    International Nuclear Information System (INIS)

    Krogh Andersen, K.; Ditlevsen, P.; Steffensen, J.P.

    2001-01-01

    Ice cores from Greenland give testimony of a highly variable climate during the last glacial period. Dramatic climate warmings of 15 to 25 deg. C for the annual average temperature in less than a human lifetime have been documented. Several questions arise: Why is the Holocene so stable? Is climatic instability only a property of glacial periods? What is the mechanism behind the sudden climate changes? Are the increased temperatures in the past century man-made? And what happens in the future? The ice core community tries to attack some of these problems. The NGRIP ice core currently being drilled is analysed in very high detail, allowing for a very precise dating of climate events. It will be possible to study some of the fast changes on a year by year basis and from this we expect to find clues to the sequence of events during rapid changes. New techniques are hoped to allow for detection of annual layers as far back as 100,000 years and thus a much improved time scale over past climate changes. It is also hoped to find ice from the Eemian period. If the Eemian layers confirm the GRIP sequence, the Eemian was actually climatically unstable just as the glacial period. This would mean that the stability of the Holocene is unique. It would also mean, that if human made global warming indeed occurs, we could jeopardize the Holocene stability and create an unstable 'Eemian situation' which ultimately could start an ice age. Currenlty mankind is changing the composition of the atmosphere. Ice cores document significant increases in greenhouse gases, and due to increased emissions of sulfuric and nitric acid from fossil fuel burning, combustion engines and agriculture, modern Greenland snow is 3 - 5 times more acidic than pre-industrial snow (Mayewski et al., 1986). However, the magnitude and abruptness of the temperature changes of the past century do not exceed the magnitude of natural variability. It is from the ice core perspective thus not possible to attribute the

  13. ICE Online Detainee Locator System

    Data.gov (United States)

    Department of Homeland Security — The Online Detainee Locator datasets provide the location of a detainee who is currently in ICE custody, or who was release from ICE custody for any reason with the...

  14. Ice recrystallization inhibition in ice cream as affected by ice structuring proteins from winter wheat grass.

    Science.gov (United States)

    Regand, A; Goff, H D

    2006-01-01

    Ice recrystallization in quiescently frozen sucrose solutions that contained some of the ingredients commonly found in ice cream and in ice cream manufactured under commercial conditions, with or without ice structuring proteins (ISP) from cold-acclimated winter wheat grass extract (AWWE), was assessed by bright field microscopy. In sucrose solutions, critical differences in moisture content, viscosity, ionic strength, and other properties derived from the presence of other ingredients (skim milk powder, corn syrup solids, locust bean gum) caused a reduction in ice crystal growth. Significant ISP activity in retarding ice crystal growth was observed in all solutions (44% for the most complex mix) containing 0.13% total protein from AWWE. In heat-shocked ice cream, ice recrystallization rates were significantly reduced 40 and 46% with the addition of 0.0025 and 0.0037% total protein from AWWE. The ISP activity in ice cream was not hindered by its inclusion in mix prior to pasteurization. A synergistic effect between ISP and stabilizer was observed, as ISP activity was reduced in the absence of stabilizer in ice cream formulations. A remarkably smoother texture for ice creams containing ISP after heat-shock storage was evident by sensory evaluation. The efficiency of ISP from AWWE in controlling ice crystal growth in ice cream has been demonstrated.

  15. The IceProd Framework

    DEFF Research Database (Denmark)

    Aartsen, M.G.; Abbasi, R.; Ackermann, M.

    2015-01-01

    of computational resources. IceProd is a distributed management system based on Python, XML-RPC and GridFTP. It is driven by a central database in order to coordinate and admin- ister production of simulations and processing of data produced by the IceCube detector. IceProd runs as a separate layer on top of other...

  16. 2006 Program of Study: Ice

    Science.gov (United States)

    2007-03-01

    form a debris flow. One such debris flow, initiated by a glacial lake flood in Peru in 1941, devastated the city of Huaraz, killing over 6000 people [5...ice, a series of’ prototype interlocking fingers is formed which grow ats the ice floes areI compressed and the ice floes plough through one another

  17. Polar Ice Caps: a Canary for the Greenland Ice Sheet

    Science.gov (United States)

    Honsaker, W.; Lowell, T. V.; Sagredo, E.; Kelly, M. A.; Hall, B. L.

    2010-12-01

    Ice caps are glacier masses that are highly sensitive to climate change. Because of their hypsometry they can have a binary state. When relatively slight changes in the equilibrium line altitude (ELA) either intersect or rise above the land the ice can become established or disappear. Thus these upland ice masses have a fast response time. Here we consider a way to extract the ELA signal from independent ice caps adjacent to the Greenland Ice Sheet margin. It may be that these ice caps are sensitive trackers of climate change that also impact the ice sheet margin. One example is the Istorvet Ice Cap located in Liverpool Land, East Greenland (70.881°N, 22.156°W). The ice cap topography and the underlying bedrock surface dips to the north, with peak elevation of the current ice ranging in elevation from 1050 to 745 m.a.s.l. On the eastern side of the ice mass the outlet glaciers extending down to sea level. The western margin has several small lobes in topographic depressions, with the margin reaching down to 300 m.a.s.l. Topographic highs separate the ice cap into at least 5 main catchments, each having a pair of outlet lobes toward either side of the ice cap. Because of the regional bedrock slope each catchment has its own elevation range. Therefore, as the ELA changes it is possible for some catchments of the ice cap to experience positive mass balance while others have a negative balance. Based on weather observations we estimate the present day ELA to be ~1000 m.a.s.l, meaning mass balance is negative for the majority of the ice cap. By tracking glacier presence/absence in these different catchments, we can reconstruct small changes in the ELA. Another example is the High Ice Cap (informal name) in Milne Land (70.903°N, 25.626°W, 1080 m), East Greenland. Here at least 4 unconformities in ice layers found near the southern margin of the ice cap record changing intervals of accumulation and ablation. Therefore, this location may also be sensitive to slight

  18. Self-generated etchant for synthetic sculpturing of Cu 2O-Au, Cu 2O@Au, Au/Cu 2O, and 3D-Au nanostructures

    KAUST Repository

    Pang, Maolin; Wang, Qingxiao; Zeng, Huachun

    2012-01-01

    Structures of Gold: A simple transformative method for nanoscale sculpturing has been developed. Five different types of complex nanocomposites of cuprite and gold have been formed by using this self-etching approach (see figure). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Self-generated etchant for synthetic sculpturing of Cu 2O-Au, Cu 2O@Au, Au/Cu 2O, and 3D-Au nanostructures

    KAUST Repository

    Pang, Maolin

    2012-10-09

    Structures of Gold: A simple transformative method for nanoscale sculpturing has been developed. Five different types of complex nanocomposites of cuprite and gold have been formed by using this self-etching approach (see figure). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Polar Stereographic Valid Ice Masks Derived from National Ice Center Monthly Sea Ice Climatologies, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — These valid ice masks provide a way to remove spurious ice caused by residual weather effects and land spillover in passive microwave data. They are derived from the...

  1. The fabrication and hydrophobic property of micro-nano patterned surface on magnesium alloy using combined sparking sculpture and etching route

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yunfeng [Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001 (China); Wang, Yaming, E-mail: wangyaming@hit.edu.cn [Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001 (China); Liu, Hao [Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001 (China); Liu, Yan [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Guo, Lixin; Jia, Dechang; Ouyang, Jiahu; Zhou, Yu [Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001 (China)

    2016-12-15

    Highlights: • A hydrophobic micro-nano roughness surface on magnesium was fabricated. • Micro-nano structure derives from duplicating ‘over growth’ regions by MAO. • 7–9 μm micro-scale big pores insetting with nano-scale fine pores were fabricated. • Hydrophobicity of micro-nano surface was improved by chemical decoration and stearic treatment. - Abstract: Magnesium alloy with micro-nano structure roughness surface, can serve as the loading reservoirs of medicine capsule and industrial lubricating oil, or mimic ‘lotus leaf’ hydrophobic surface, having the potential applications in medical implants, automobile, aerospace and electronic products, etc. Herein, we propose a novel strategy to design a micro-nano structure roughness surface on magnesium alloy using combined microarc sparking sculpture and etching in CrO{sub 3} aqueous solution. A hydrophobic surface (as an applied example) was further fabricated by chemical decorating on the obtained patterned magnesium alloy surface to enhance the corrosion resistance. The results show that the combined micro-nano structure of 7–9 μm diameter big pores insetting with nano-scale fine pores was duplicated after etched the sparking sculptured ‘over growth’ oxide regions towards the magnesium substrate. The micro-nano structure surface was chemically decorated using AgNO{sub 3} and stearic acid, which enables the contact angle increased from 60° to 146.8°. The increasing contact angle is mainly attributed to the micro-nano structure and the chemical composition. The hydrophobic surface of magnesium alloy improved the corrosion potential from −1.521 V of the bare magnesium to −1.274 V. Generally, the sparking sculpture and then etching route demonstrates a low-cost, high-efficacy method to fabricate a micro-nano structure hydrophobic surface on magnesium alloy. Furthermore, our research on the creating of micro-nano structure roughness surface and the hydrophobic treatment can be easily

  2. The fabrication and hydrophobic property of micro-nano patterned surface on magnesium alloy using combined sparking sculpture and etching route

    International Nuclear Information System (INIS)

    Wu, Yunfeng; Wang, Yaming; Liu, Hao; Liu, Yan; Guo, Lixin; Jia, Dechang; Ouyang, Jiahu; Zhou, Yu

    2016-01-01

    Highlights: • A hydrophobic micro-nano roughness surface on magnesium was fabricated. • Micro-nano structure derives from duplicating ‘over growth’ regions by MAO. • 7–9 μm micro-scale big pores insetting with nano-scale fine pores were fabricated. • Hydrophobicity of micro-nano surface was improved by chemical decoration and stearic treatment. - Abstract: Magnesium alloy with micro-nano structure roughness surface, can serve as the loading reservoirs of medicine capsule and industrial lubricating oil, or mimic ‘lotus leaf’ hydrophobic surface, having the potential applications in medical implants, automobile, aerospace and electronic products, etc. Herein, we propose a novel strategy to design a micro-nano structure roughness surface on magnesium alloy using combined microarc sparking sculpture and etching in CrO_3 aqueous solution. A hydrophobic surface (as an applied example) was further fabricated by chemical decorating on the obtained patterned magnesium alloy surface to enhance the corrosion resistance. The results show that the combined micro-nano structure of 7–9 μm diameter big pores insetting with nano-scale fine pores was duplicated after etched the sparking sculptured ‘over growth’ oxide regions towards the magnesium substrate. The micro-nano structure surface was chemically decorated using AgNO_3 and stearic acid, which enables the contact angle increased from 60° to 146.8°. The increasing contact angle is mainly attributed to the micro-nano structure and the chemical composition. The hydrophobic surface of magnesium alloy improved the corrosion potential from −1.521 V of the bare magnesium to −1.274 V. Generally, the sparking sculpture and then etching route demonstrates a low-cost, high-efficacy method to fabricate a micro-nano structure hydrophobic surface on magnesium alloy. Furthermore, our research on the creating of micro-nano structure roughness surface and the hydrophobic treatment can be easily extended to the

  3. User's guide for ICE

    International Nuclear Information System (INIS)

    Fraley, S.K.

    1976-07-01

    ICE is a cross-section mixing code which will accept cross sections from an AMPX working library and produce mixed cross sections in the AMPX working library format, ANISN format, and the group-independent ANISN format. User input is in the free-form or fixed-form FIDO structure. The code is operable as a module in the AMPX system

  4. Autosub under ice

    OpenAIRE

    Griffiths, G.

    2005-01-01

    Autosub made headlines recently when it became trapped under 200m of ice in Antarctica.Here we explore the ideas behind the £5.86 million research programme, and look back at an earlier expedition which took place last summer off the coast of Greenland.

  5. Melting ice, growing trade?

    Directory of Open Access Journals (Sweden)

    Sami Bensassi

    2016-05-01

    Full Text Available Abstract Large reductions in Arctic sea ice, most notably in summer, coupled with growing interest in Arctic shipping and resource exploitation have renewed interest in the economic potential of the Northern Sea Route (NSR. Two key constraints on the future viability of the NSR pertain to bathymetry and the future evolution of the sea ice cover. Climate model projections of future sea ice conditions throughout the rest of the century suggest that even under the most “aggressive” emission scenario, increases in international trade between Europe and Asia will be very low. The large inter-annual variability of weather and sea ice conditions in the route, the Russian toll imposed for transiting the NSR, together with high insurance costs and scarce loading/unloading opportunities, limit the use of the NSR. We show that even if these obstacles are removed, the duration of the opening of the NSR over the course of the century is not long enough to offer a consequent boost to international trade at the macroeconomic level.

  6. Ecology under lake ice

    NARCIS (Netherlands)

    Hampton, Stephanie E.; Galloway, Aaron W. E.; Powers, Stephen M.; Ozersky, Ted; Woo, Kara H.; Batt, Ryan D.; Labou, Stephanie G.; O'Reilly, Catherine M.; Sharma, Sapna; Lottig, Noah R.; Stanley, Emily H.; North, Rebecca L.; Stockwell, Jason D.; Adrian, Rita; Weyhenmeyer, Gesa A.; Arvola, Lauri; Baulch, Helen M.; Bertani, Isabella; Bowman, Larry L., Jr.; Carey, Cayelan C.; Catalan, Jordi; Colom-Montero, William; Domine, Leah M.; Felip, Marisol; Granados, Ignacio; Gries, Corinna; Grossart, Hans-Peter; Haberman, Juta; Haldna, Marina; Hayden, Brian; Higgins, Scott N.; Jolley, Jeff C.; Kahilainen, Kimmo K.; Kaup, Enn; Kehoe, Michael J.; MacIntyre, Sally; Mackay, Anson W.; Mariash, Heather L.; Mckay, Robert M.; Nixdorf, Brigitte; Noges, Peeter; Noges, Tiina; Palmer, Michelle; Pierson, Don C.; Post, David M.; Pruett, Matthew J.; Rautio, Milla; Read, Jordan S.; Roberts, Sarah L.; Ruecker, Jacqueline; Sadro, Steven; Silow, Eugene A.; Smith, Derek E.; Sterner, Robert W.; Swann, George E. A.; Timofeyev, Maxim A.; Toro, Manuel; Twiss, Michael R.; Vogt, Richard J.; Watson, Susan B.; Whiteford, Erika J.; Xenopoulos, Marguerite A.

    Winter conditions are rapidly changing in temperate ecosystems, particularly for those that experi-ence periods of snow and ice cover. Relatively little is known of winter ecology in these systems,due to a historical research focus on summer ‘growing seasons’. We executed the first global

  7. Ice shelf fracture parameterization in an ice sheet model

    Directory of Open Access Journals (Sweden)

    S. Sun

    2017-11-01

    Full Text Available Floating ice shelves exert a stabilizing force onto the inland ice sheet. However, this buttressing effect is diminished by the fracture process, which on large scales effectively softens the ice, accelerating its flow, increasing calving, and potentially leading to ice shelf breakup. We add a continuum damage model (CDM to the BISICLES ice sheet model, which is intended to model the localized opening of crevasses under stress, the transport of those crevasses through the ice sheet, and the coupling between crevasse depth and the ice flow field and to carry out idealized numerical experiments examining the broad impact on large-scale ice sheet and shelf dynamics. In each case we see a complex pattern of damage evolve over time, with an eventual loss of buttressing approximately equivalent to halving the thickness of the ice shelf. We find that it is possible to achieve a similar ice flow pattern using a simple rule of thumb: introducing an enhancement factor ∼ 10 everywhere in the model domain. However, spatially varying damage (or equivalently, enhancement factor fields set at the start of prognostic calculations to match velocity observations, as is widely done in ice sheet simulations, ought to evolve in time, or grounding line retreat can be slowed by an order of magnitude.

  8. Ice shelf fracture parameterization in an ice sheet model

    Science.gov (United States)

    Sun, Sainan; Cornford, Stephen L.; Moore, John C.; Gladstone, Rupert; Zhao, Liyun

    2017-11-01

    Floating ice shelves exert a stabilizing force onto the inland ice sheet. However, this buttressing effect is diminished by the fracture process, which on large scales effectively softens the ice, accelerating its flow, increasing calving, and potentially leading to ice shelf breakup. We add a continuum damage model (CDM) to the BISICLES ice sheet model, which is intended to model the localized opening of crevasses under stress, the transport of those crevasses through the ice sheet, and the coupling between crevasse depth and the ice flow field and to carry out idealized numerical experiments examining the broad impact on large-scale ice sheet and shelf dynamics. In each case we see a complex pattern of damage evolve over time, with an eventual loss of buttressing approximately equivalent to halving the thickness of the ice shelf. We find that it is possible to achieve a similar ice flow pattern using a simple rule of thumb: introducing an enhancement factor ˜ 10 everywhere in the model domain. However, spatially varying damage (or equivalently, enhancement factor) fields set at the start of prognostic calculations to match velocity observations, as is widely done in ice sheet simulations, ought to evolve in time, or grounding line retreat can be slowed by an order of magnitude.

  9. Autonomous Ice Mass Balance Buoys for Seasonal Sea Ice

    Science.gov (United States)

    Whitlock, J. D.; Planck, C.; Perovich, D. K.; Parno, J. T.; Elder, B. C.; Richter-Menge, J.; Polashenski, C. M.

    2017-12-01

    The ice mass-balance represents the integration of all surface and ocean heat fluxes and attributing the impact of these forcing fluxes on the ice cover can be accomplished by increasing temporal and spatial measurements. Mass balance information can be used to understand the ongoing changes in the Arctic sea ice cover and to improve predictions of future ice conditions. Thinner seasonal ice in the Arctic necessitates the deployment of Autonomous Ice Mass Balance buoys (IMB's) capable of long-term, in situ data collection in both ice and open ocean. Seasonal IMB's (SIMB's) are free floating IMB's that allow data collection in thick ice, thin ice, during times of transition, and even open water. The newest generation of SIMB aims to increase the number of reliable IMB's in the Arctic by leveraging inexpensive commercial-grade instrumentation when combined with specially developed monitoring hardware. Monitoring tasks are handled by a custom, expandable data logger that provides low-cost flexibility for integrating a large range of instrumentation. The SIMB features ultrasonic sensors for direct measurement of both snow depth and ice thickness and a digital temperature chain (DTC) for temperature measurements every 2cm through both snow and ice. Air temperature and pressure, along with GPS data complete the Arctic picture. Additionally, the new SIMB is more compact to maximize deployment opportunities from multiple types of platforms.

  10. Improved ice loss estimate of the northwestern Greenland ice sheet

    DEFF Research Database (Denmark)

    Kjeldsen, Kristian Kjellerup; Khan, Shfaqat Abbas; Wahr, J.

    2013-01-01

    We estimate ice volume change rates in the northwest Greenland drainage basin during 2003–2009 using Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter data. Elevation changes are often reported to be largest near the frontal portion of outlet glaciers. To improve the volume change...... estimate, we supplement the ICESat data with altimeter surveys from NASA's Airborne Topographic Mapper from 2002 to 2010 and NASA's Land, Vegetation and Ice Sensor from 2010. The Airborne data are mainly concentrated along the ice margin and thus have a significant impact on the estimate of the volume...... change. Our results show that adding Airborne Topographic Mapper and Land, Vegetation and Ice Sensor data to the ICESat data increases the catchment-wide estimate of ice volume loss by 11%, mainly due to an improved volume loss estimate along the ice sheet margin. Furthermore, our results show...

  11. Heterogeneous ice nucleation

    Energy Technology Data Exchange (ETDEWEB)

    Bogdan, A. [Helsinki Univ. (Finland). Dept. of Physics

    1994-12-31

    The classical theory of heterogenous ice nucleation is reviewed in detail. The modelling of ice nucleation in the adsorbed water films on natural particles by analogous ice nucleation in adsorbed water films on the walls of porous media is discussed. Ice nucleation in adsorbed films of purewater and the HNO{sub 3}/H{sub 2}0 binary system on the surface of porous aerosol (SiO{sub 2}) was investigated using the method of NMR spectroscopy. The median freezing temperature and freezing temperature region were shown to be highly sensitive both to the average thickness of the adsorbed films and to the amount of adsorbed nitric acid. The character of the ice phase formation tends to approach that of bulk liquid with increasing adsorbed film thickness. Under the given conditions the thickness of the adsorbed films decreases with an increasing amount of adsorbed nitric acid molecules The molar concentration of nitric acid in the adsorbed films is very small (of the order of 10{sup -}3 10{sup -}2 (M/l)). Nitric acid molecules tend to adsorb on the surface of aerosol to a greater extent than in subsequent layers. The concentration is greatest in layers situated close to the surface and sharply decreases with the distance from the surface. The difference between the median freezing temperatures for adsorbed pure water and for the binary system was found to be about 9 K for films of equal thickness. This is about 150 times greater than the difference between the median freezing temperatures of bulk pure water and a solution with the same concentration of nitric acid. (orig.)

  12. Bibliography of Ice Properties and Forecasting Related to Transportation in Ice-Covered Waters.

    Science.gov (United States)

    1980-09-01

    N. and Tabata , T., Ice study in the Gulf of Peschanskii, I.S., Ice science and ice technology, Bothnia, III: observations on large grains of ice...ice and by Sterrett, K.F., The arctic environment and the hitting ice floes. Results of these measurements have arctic surface effect vehicle, Cold...ice growth, temperature 26-3673 effects, ice cover thickness. 28-557 Determining contact stresses when a ship’s stem hits the ice, Kheisin, D.E

  13. RELIEF JENIS-JENIS FAUNA DAN SETTING LINGKUNGANNYA PADA PAHATAN DINDING CANDI BOROBUDUR (Fauna and Environmental Setting Reliefs on Sculptured Wall of the Borobudur Temple

    Directory of Open Access Journals (Sweden)

    Bambang Agus Suripto

    2001-04-01

    cavewalls inhabited by human, temples, pyramids, and sphinxes. Sculptures on the wall of Borobudur Temple, show fauna reliefs, but the originof the fauna are still obscure, whether or not they came from India or part of them were from Java. The objectives of this research were to determine the species of group names of the fauna picture in the reliefs on the sculptured wall of the Borobudur Temple, Their origin, and to assess whether of not Java environment settings were depicted in the wall. Pictures of fauna reliefs in sculpture wall of langkan, the main wall from top to bottom in each Rupadhatu levels were taken, the name of each fauna species or group was identified using identification books, and their origins were determined through a literature study. Data were interpreted descriptively in order to understand whether of not Java environment settings were portrayed in the sculptured wall of the Borobudur Temple. There are at least 25 species of Osteighthyes, Reptilia, aves and Mammalia classess pictured naturally in the reliefs of the wall, and at least 5 species are pictured setilirly. These entire fauna naturally found in south Asia. Some of them have never lived in Java Island, such as lion, Pantera leo. Environment settings of seventh centure India were illustrated very well in the reliefs however, those of Java until the Dutch colonial era were  not pictured at all.

  14. Experimental provocation of 'ice-cream headache' by ice cubes and ice water.

    Science.gov (United States)

    Mages, Stephan; Hensel, Ole; Zierz, Antonia Maria; Kraya, Torsten; Zierz, Stephan

    2017-04-01

    Background There are various studies on experimentally provoked 'ice-cream headache' or 'headache attributed to ingestion or inhalation of a cold stimulus' (HICS) using different provocation protocols. The aim of this study was to compare two provocation protocols. Methods Ice cubes pressed to the palate and fast ingestion of ice water were used to provoke HICS and clinical features were compared. Results The ice-water stimulus provoked HICS significantly more often than the ice-cube stimulus (9/77 vs. 39/77). Ice-water-provoked HICS had a significantly shorter latency (median 15 s, range 4-97 s vs. median 68 s, range 27-96 s). There was no difference in pain localisation. Character after ice-cube stimulation was predominantly described as pressing and after ice-water stimulation as stabbing. A second HICS followed in 10/39 (26%) of the headaches provoked by ice water. Lacrimation occurred significantly more often in volunteers with than in those without HICS. Discussion HICS provoked by ice water was more frequent, had a shorter latency, different pain character and higher pain intensity than HICS provoked by ice cubes. The finding of two subsequent HICS attacks in the same volunteers supports the notion that two types of HICS exist. Lacrimation during HICS indicates involvement of the trigeminal-autonomic reflex.

  15. GPR capabilities for ice thickness sampling of low salinity ice and for detecting oil in ice

    Energy Technology Data Exchange (ETDEWEB)

    Lalumiere, Louis [Sensors by Design Ltd. (Canada)

    2011-07-01

    This report discusses the performance and capabilities test of two airborne ground-penetrating radar (GPR) systems of the Bedford Institute of Oceanography (BIO), Noggin 1000 and Noggin 500, for monitoring low salinity snow and ice properties which was used to measure the thickness of brackish ice on Lake Melville in Labrador and on a tidal river in Prince Edward Island. The work of other researchers is documented and the measurement techniques proposed are compared to the actual GPR approach. Different plots of GPR data taken over snow and freshwater ice and over ice with changing salinity are discussed. An interpretation of brackish ice GPR plots done by the Noggin 1000 and Noggin 500 systems is given based on resolution criterion. Additionally, the capability of the BIO helicopter-borne GPR to detect oil-in-ice has been also investigated, and an opinion on the likelihood of the success of GPR as an oil-in-ice detector is given.

  16. Animals and ICE

    DEFF Research Database (Denmark)

    van Hemmen, J Leo; Christensen-Dalsgaard, Jakob; Carr, Catherine E

    2016-01-01

    experimental and mathematical foundation, it is known that there is a low-frequency regime where the internal time difference (iTD) as perceived by the animal may well be 2-5 times higher than the external ITD, the interaural time difference, and that there is a frequency plateau over which the fraction i......TD/ITD is constant. There is also a high-frequency regime where the internal level (amplitude) difference iLD as perceived by the animal is much higher than the interaural level difference ILD measured externally between the two ears. The fundamental tympanic frequency segregates the two regimes. The present special...... issue devoted to "internally coupled ears" provides an overview of many aspects of ICE, be they acoustic, anatomical, auditory, mathematical, or neurobiological. A focus is on the hotly debated topic of what aspects of ICE animals actually exploit neuronally to localize a sound source....

  17. Skating on slippery ice

    Directory of Open Access Journals (Sweden)

    J. M. J. van Leeuwen

    2017-12-01

    Full Text Available The friction of a stationary moving skate on smooth ice is investigated, in particular in relation to the formation of a thin layer of water between skate and ice. It is found that the combination of ploughing and sliding gives a friction force that is rather insensitive for parameters such as velocity and temperature. The weak dependence originates from the pressure adjustment inside the water layer. For instance, high velocities, which would give rise to high friction, also lead to large pressures, which, in turn, decrease the contact zone and so lower the friction. The theory is a combination and completion of two existing but conflicting theories on the formation of the water layer.

  18. Theory of amorphous ices.

    Science.gov (United States)

    Limmer, David T; Chandler, David

    2014-07-01

    We derive a phase diagram for amorphous solids and liquid supercooled water and explain why the amorphous solids of water exist in several different forms. Application of large-deviation theory allows us to prepare such phases in computer simulations. Along with nonequilibrium transitions between the ergodic liquid and two distinct amorphous solids, we establish coexistence between these two amorphous solids. The phase diagram we predict includes a nonequilibrium triple point where two amorphous phases and the liquid coexist. Whereas the amorphous solids are long-lived and slowly aging glasses, their melting can lead quickly to the formation of crystalline ice. Further, melting of the higher density amorphous solid at low pressures takes place in steps, transitioning to the lower-density glass before accessing a nonequilibrium liquid from which ice coarsens.

  19. Arctic Ice Studies

    Science.gov (United States)

    1993-02-01

    i heoriotlscale wace s 50 kin wthe11 aii vertical leadi tof M o.ChrlesA Lcur the siir-ai’.orc~5 . ~ ~G. RLI Lt(lWA~S II I Shuchln P A P Ut alI 9...can be utilized msccesafully. distinguish between these two major ice types and open I. INTRODUCTION water. S THE geophysical and economic importance of

  20. Car engine breather icing

    OpenAIRE

    Horoufi, Aryan

    2012-01-01

    Icing in an engine breather system can block the engine breather pipe, cause excessive crankcase pressure and degrade the engine performance. In this project, a numerical study, experimental tests and CFD analysis are employed in order to understand condensation and the extent of freezing inside a vertical pipe, a horizontal pipe and a T-joint pipe which are exposed to an external convective cooling. The pipe internal flow is assumed to be a vapour/air mixture. This study has l...

  1. Marginal Ice Zone Bibliography.

    Science.gov (United States)

    1985-06-01

    Tsunamis, Gravimetry , Earth Tides, World Data Center A: Oceanography Recent Movements of the Earth’s National Oceanographic Data Center Crust...sufficiently low, the dissolved salts precipitate out in the form of solid hydrates. It has been proposed that these solid hydrates add to the overall...strength of the ice. The first salt hydrate to precipitate should be that of sodium sul- * fate, Na2SO4IOH2O (the sulfate ion is the second most

  2. Ice condenser experimental plan

    International Nuclear Information System (INIS)

    Kannberg, L.D.; Piepel, G.F.; Owczarski, P.C.; Liebetrau, A.M.

    1986-01-01

    An experimental plan is being developed to validate the computer code ICEDF. The code was developed to estimate the extent of aerosol retention in the ice compartments of pressurized water reactor ice condenser containment systems during severe accidents. The development of the experimental plan began with review of available information on the conditions under which the code will be applied. Computer-generated estimates of thermohydraulic and aerosol conditions entering the ice condenser were evaluated and along with other information, used to generate design criteria. The design criteria have been used for preliminary test assembly design and for generation of statistical test designs. Consideration of the phenomena to be evaluated in the testing program, as well as equipment and measurement limitations, have led to changes in the design criteria and to subsequent changes in the test assembly design and statistical test design. The overall strategy in developing the experimental plan includes iterative generation and evaluation of candidate test designs using computer codes for statistical test design and ICEDF for estimation of experimental results. Estimates of experimental variability made prior to actual testing will be verified by replicate testing at preselected design points

  3. Using ice melting and ice rolling technologies to remove ice from sub-transmission and transmission lines at Manitoba Hydro

    International Nuclear Information System (INIS)

    Farias, A. R.

    1999-01-01

    Development of an of an Ice Storm Management program by Manitoba Hydro to reduce ice storm damage to its 8 kV feeders to 115 kV transmission lines, is discussed. The program consists of the de-icing of overhead lines, either by ice melting, or ice rolling. Ice melting involves the placement of a three-phase short at a calculated point. The term ice rolling denotes a process of mechanically stripping the ice from conductors. The most recent major ice storm experienced by Manitoba Hydro was in the winter of 1997/1998. During the period from February 6 to February 17, 1998, a total of 83 'ice melt' procedures were performed to melt the ice from 2,628 km of overhead line (7,883 km of conductor), in addition to 'ice rolling'. This paper describes Manitoba Hydro's 25-years' experience with ice melting and it also describes the advantages and disadvantages of both ice melting and ice rolling. Although not a panacea to combat the effects of ice storms, ice melting was found to be the most effective way of removing ice from overhead transmission and sub-transmission lines. Ice rolling was also found to be effective. Other tools that have been found to be useful by various utilities in combating ice storm damage include improved structure and line design, system design that provide more redundancies and emergency sources, and standby generators at critical load points

  4. IceCube systematic errors investigation: Simulation of the ice

    Energy Technology Data Exchange (ETDEWEB)

    Resconi, Elisa; Wolf, Martin [Max-Planck-Institute for Nuclear Physics, Heidelberg (Germany); Schukraft, Anne [RWTH, Aachen University (Germany)

    2010-07-01

    IceCube is a neutrino observatory for astroparticle and astronomy research at the South Pole. It uses one cubic kilometer of Antartica's deepest ice (1500 m-2500 m in depth) to detect Cherenkov light, generated by charged particles traveling through the ice, with an array of phototubes encapsulated in glass pressure spheres. The arrival time as well as the charge deposited of the detected photons represent the base measurements that are used for track and energy reconstruction of those charged particles. The optical properties of the deep antarctic ice vary from layer to layer. Measurements of the ice properties and their correct modeling in Monte Carlo simulation is then of primary importance for the correct understanding of the IceCube telescope behavior. After a short summary about the different methods to investigate the ice properties and to calibrate the detector, we show how the simulation obtained by using this information compares to the measured data and how systematic errors due to uncertain ice properties are determined in IceCube.

  5. Radiation effects in ice: New results

    International Nuclear Information System (INIS)

    Baragiola, R.A.; Fama, M.; Loeffler, M.J.; Raut, U.; Shi, J.

    2008-01-01

    Studies of radiation effects in ice are motivated by intrinsic interest and by applications in astronomy. Here we report on new and recent results on radiation effects induced by energetic ions in ice: amorphization of crystalline ice, compaction of microporous amorphous ice, electrostatic charging and dielectric breakdown and correlated structural/chemical changes in the irradiation of water-ammonia ices

  6. The making of salty ice

    International Nuclear Information System (INIS)

    Bove, L.E.

    2009-01-01

    Full text: It is widely accepted that ice, no matter what phase, is unable to incorporate large amount of salt into its structure. This conclusion is based on the observation that upon freezing of saltwater, ice expels the salt almost entirely into brine, a fact which can be exploited to desalinate seawater. Here we show, by neutron diffraction under high pressure, that this behaviour is not an intrinsic physico-chemical property of ice phases. We demonstrate that substantial am mounts of dissolved LiCl can be built homogeneously into the ice VII structure if it is produced by recrystallisation of its glassy state under pressure [1]. Such highly doped or alloyed ice VII has significantly different structural properties compared to pure ice VII, such as a 8% larger unit cell volume, 5 times larger displacement factors, an absence of a transition to an ordered ice VIII structure, plasticity, and most likely ionic conductivity. Our study suggests that there could be a whole new class of salty ices based on various kinds of solutes and high pressure ice forms. (author)

  7. Diffuse scattering in Ih ice

    International Nuclear Information System (INIS)

    Wehinger, Björn; Krisch, Michael; Bosak, Alexeï; Chernyshov, Dmitry; Bulat, Sergey; Ezhov, Victor

    2014-01-01

    Single crystals of ice Ih, extracted from the subglacial Lake Vostok accretion ice layer (3621 m depth) were investigated by means of diffuse x-ray scattering and inelastic x-ray scattering. The diffuse scattering was identified as mainly inelastic and rationalized in the frame of ab initio calculations for the ordered ice XI approximant. Together with Monte-Carlo modelling, our data allowed reconsidering previously available neutron diffuse scattering data of heavy ice as the sum of thermal diffuse scattering and static disorder contribution. (paper)

  8. Modelling the Antarctic Ice Sheet

    DEFF Research Database (Denmark)

    Pedersen, Jens Olaf Pepke; Holm, A.

    2015-01-01

    to sea level high stands during past interglacial periods. A number of AIS models have been developed and applied to try to understand the workings of the AIS and to form a robust basis for future projections of the AIS contribution to sea level change. The recent DCESS (Danish Center for Earth System......The Antarctic ice sheet is a major player in the Earth’s climate system and is by far the largest depository of fresh water on the planet. Ice stored in the Antarctic ice sheet (AIS) contains enough water to raise sea level by about 58 m, and ice loss from Antarctica contributed significantly...

  9. Improved ice loss estimate of the northwestern Greenland ice sheet

    NARCIS (Netherlands)

    Kjeldsen, K.K.; Khan, S.A.; van den Broeke, M.R.; van Angelen, J.H.

    2013-01-01

    We estimate ice volume change rates in the northwest Greenland drainage basin during 2003–2009 using Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter data. Elevation changes are often reported to be largest near the frontal portion of outlet glaciers. To improve the volume change

  10. Eulerian method for ice crystal icing in turbofan engines

    NARCIS (Netherlands)

    Norde, Ellen

    2017-01-01

    The newer generations of high-bypass-ratio engines are susceptible to the ingestion of small ice crystals which may cause engine power loss or damage. The research presented in this thesis focusses on the development of a computational method for in-engine ice crystal accretion. The work has been

  11. Tropospheric characteristics over sea ice during N-ICE2015

    Science.gov (United States)

    Kayser, Markus; Maturilli, Marion; Graham, Robert; Hudson, Stephen; Cohen, Lana; Rinke, Annette; Kim, Joo-Hong; Park, Sang-Jong; Moon, Woosok; Granskog, Mats

    2017-04-01

    Over recent years, the Arctic Ocean region has shifted towards a younger and thinner sea-ice regime. The Norwegian young sea ICE (N-ICE2015) expedition was designed to investigate the atmosphere-snow-ice-ocean interactions in this new ice regime north of Svalbard. Here we analyze upper-air measurements made by radiosondes launched twice daily together with surface meteorology observations during N-ICE2015 from January to June 2015. We study the multiple cyclonic events observed during N-ICE2015 with respect to changes in the vertical thermodynamic structure, sudden increases in moisture content and temperature, temperature inversions and boundary layer dynamics. The influence of synoptic cyclones is strongest under polar night conditions, when radiative cooling is most effective and the moisture content is low. We find that transitions between the radiatively clear and opaque state are the largest drivers of changes to temperature inversion and stability characteristics in the boundary layer during winter. In spring radiative fluxes warm the surface leading to lifted temperature inversions and a statically unstable boundary layer. The unique N-ICE2015 dataset is used for case studies investigating changes in the vertical structure of the atmosphere under varying synoptic conditions. The goal is to deepen our understanding of synoptic interactions within the Arctic climate system, to improve model performance, as well as to identify gaps in instrumentation, which precludes further investigations.

  12. Arctic Sea Ice Freeboard and Thickness

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides measurements of sea ice freeboard and sea ice thickness for the Arctic region. The data were derived from measurements made by from the Ice,...

  13. Climate Impacts of Ice Nucleation

    Science.gov (United States)

    Gettelman, Andrew; Liu, Xiaohong; Barahona, Donifan; Lohmann, Ulrike; Chen, Celia

    2012-01-01

    Several different ice nucleation parameterizations in two different General Circulation Models (GCMs) are used to understand the effects of ice nucleation on the mean climate state, and the Aerosol Indirect Effects (AIE) of cirrus clouds on climate. Simulations have a range of ice microphysical states that are consistent with the spread of observations, but many simulations have higher present-day ice crystal number concentrations than in-situ observations. These different states result from different parameterizations of ice cloud nucleation processes, and feature different balances of homogeneous and heterogeneous nucleation. Black carbon aerosols have a small (0.06 Wm(exp-2) and not statistically significant AIE when included as ice nuclei, for nucleation efficiencies within the range of laboratory measurements. Indirect effects of anthropogenic aerosols on cirrus clouds occur as a consequence of increasing anthropogenic sulfur emissions with different mechanisms important in different models. In one model this is due to increases in homogeneous nucleation fraction, and in the other due to increases in heterogeneous nucleation with coated dust. The magnitude of the effect is the same however. The resulting ice AIE does not seem strongly dependent on the balance between homogeneous and heterogeneous ice nucleation. Regional effects can reach several Wm2. Indirect effects are slightly larger for those states with less homogeneous nucleation and lower ice number concentration in the base state. The total ice AIE is estimated at 0.27 +/- 0.10 Wm(exp-2) (1 sigma uncertainty). This represents a 20% offset of the simulated total shortwave AIE for ice and liquid clouds of 1.6 Wm(sup-2).

  14. Ice hockey injuries.

    Science.gov (United States)

    Benson, Brian W; Meeuwisse, Willem H

    2005-01-01

    This article reviews the distribution and determinants of injuries reported in the pediatric ice hockey literature, and suggests potential injury prevention strategies and directions for further research. Thirteen electronic databases, the ISI Web of Science, and 'grey literature' databases were searched using a combination of Medical Subject Headings and text words to identify potentially relevant articles. The bibliographies of selected studies were searched to identify additional articles. Studies were selected for review based on predetermined inclusion and exclusion criteria. A comparison between studies on this topic area was difficult due to the variability in research designs, definition of injury, study populations, and measurements used to assess injury. The majority of injuries were sustained during games compared with practices. The two most commonly reported injuries were sprains/strains and contusions. Players competing at the Minor hockey, High School, and Junior levels of competition sustained most of their injuries to the upper extremity, head, and lower extremity, respectively. The primary mechanism of injury was body checking, followed by stick and puck contact. The frequency of catastrophic eye injuries has been significantly reduced with the world-wide mandation of full facial protection for all Minor hockey players. Specific hockey-related injury risk factors are poorly delineated and rarely studied among pediatric ice hockey players leaving large gaps in the knowledge of appropriate prevention strategies. Risk management strategies should be focused at avoiding unnecessary foreseeable risk, and controlling the risks inherent to the sport. Suggestions for injury prevention and future research are discussed.

  15. The physics of ice cream

    Science.gov (United States)

    Clarke, Chris

    2003-05-01

    Almost everybody likes ice cream, so it can provide an excellent vehicle for discussing and demonstrating a variety of physical phenomena, such as Newton's law of cooling, Boyle's law and the relationship between microstructure and macroscopic properties (e.g. Young's modulus). Furthermore, a demonstration of freezing point depression can be used to make ice cream in the classroom!

  16. Snow, ice and solar radiation

    NARCIS (Netherlands)

    Kuipers Munneke, P.

    2009-01-01

    The snow-covered ice sheets of Antarctica and Greenland reflect most of the incoming solar radiation. The reflectivity, commonly called the albedo, of snow on these ice sheets has been observed to vary in space and time. In this thesis, temporal and spatial changes in snow albedo is found to depend

  17. Ice as a Construction Material

    Science.gov (United States)

    Zuppero, Anthony; Lewis, Joseph

    1998-01-01

    The use of ice as a construction material is discussed. A model of an ice tire torus space ship, which slowly spins to produce artificial gravity is proposed. The size of the ship, needed to support a given number of people and the required envelope mass is presented.

  18. Ice sheet hydrology from observations

    Energy Technology Data Exchange (ETDEWEB)

    Jansson, Peter [Dept. of Physical Geography and Quaternary Geology, Stockholm Univ-, Stockholm (Sweden)

    2010-11-15

    The hydrological systems of ice sheets are complex. Our view of the system is split, largely due to the complexity of observing the systems. Our basic knowledge of processes have been obtained from smaller glaciers and although applicable in general to the larger scales of the ice sheets, ice sheets contain features not observable on smaller glaciers due to their size. The generation of water on the ice sheet surface is well understood and can be satisfactorily modeled. The routing of water from the surface down through the ice is not complicated in terms of procat has been problematic is the way in which the couplings between surface and bed has been accomplished through a kilometer of cold ice, but with the studies on crack propagation and lake drainage on Greenland we are beginning to understand also this process and we know water can be routed through thick cold ice. Water generation at the bed is also well understood but the main problem preventing realistic estimates of water generation is lack of detailed information about geothermal heat fluxes and their geographical distribution beneath the ice. Although some average value for geothermal heat flux may suffice, for many purposes it is important that such values are not applied to sub-regions of significantly higher fluxes. Water generated by geothermal heat constitutes a constant supply and will likely maintain a steady system beneath the ice sheet. Such a system may include subglacial lakes as steady features and reconfiguration of the system is tied to time scales on which the ice sheet geometry changes so as to change pressure gradients in the basal system itself. Large scale re-organization of subglacial drainage systems have been observed beneath ice streams. The stability of an entirely subglacially fed drainage system may hence be perturbed by rapid ice flow. In the case of Antarctic ice streams where such behavior has been observed, the ice streams are underlain by deformable sediments. It is

  19. Ice sheet hydrology from observations

    International Nuclear Information System (INIS)

    Jansson, Peter

    2010-11-01

    The hydrological systems of ice sheets are complex. Our view of the system is split, largely due to the complexity of observing the systems. Our basic knowledge of processes have been obtained from smaller glaciers and although applicable in general to the larger scales of the ice sheets, ice sheets contain features not observable on smaller glaciers due to their size. The generation of water on the ice sheet surface is well understood and can be satisfactorily modeled. The routing of water from the surface down through the ice is not complicated in terms of procat has been problematic is the way in which the couplings between surface and bed has been accomplished through a kilometer of cold ice, but with the studies on crack propagation and lake drainage on Greenland we are beginning to understand also this process and we know water can be routed through thick cold ice. Water generation at the bed is also well understood but the main problem preventing realistic estimates of water generation is lack of detailed information about geothermal heat fluxes and their geographical distribution beneath the ice. Although some average value for geothermal heat flux may suffice, for many purposes it is important that such values are not applied to sub-regions of significantly higher fluxes. Water generated by geothermal heat constitutes a constant supply and will likely maintain a steady system beneath the ice sheet. Such a system may include subglacial lakes as steady features and reconfiguration of the system is tied to time scales on which the ice sheet geometry changes so as to change pressure gradients in the basal system itself. Large scale re-organization of subglacial drainage systems have been observed beneath ice streams. The stability of an entirely subglacially fed drainage system may hence be perturbed by rapid ice flow. In the case of Antarctic ice streams where such behavior has been observed, the ice streams are underlain by deformable sediments. It is

  20. The IceProd (IceCube Production) Framework

    International Nuclear Information System (INIS)

    Díaz-Vélez, J C

    2014-01-01

    IceProd is a data processing and management framework developed by the IceCube Neutrino Observatory for processing of Monte Carlo simulations and data. IceProd runs as a separate layer on top of middleware or cluster job schedulers and can take advantage of a variety of computing resources including grids such as EGI, OSG, and NorduGrid as well as local clusters running batch systems like HT Condor, PBS, and SGE. This is accomplished by a set of dedicated daemons which process job submission in a coordinated fashion through the use of middleware plug-ins that serve to abstract the details of job submission and job management. IceProd can also manage complex workflow DAGs across distributed computing grids in order to optimize usage of resources. We describe several aspects of IceProd's design and it's applications in collaborative computing environments. We also briefly discuss design aspects of a second generation IceProd, currently being tested in IceCube.

  1. Little Ice Age Fluctuations of Quelccaya Ice Cap, Peru

    Science.gov (United States)

    Stroup, J. S.; Kelly, M. A.; Lowell, T.

    2009-12-01

    A record of the past extents of Quelccaya Ice Cap (QIC) provides valuable information about tropical climate change from late glacial to recent time. Here, we examine the timing and regional significance of fluctuations of QIC during the Little Ice Age (LIA; ~1300-1850 AD). One prominent set of moraines, known as the Huancane I moraines, is located ~1 km from the present-day western ice cap margin and provides a near-continuous outline of the most recent advance of QIC. This moraine set was radiocarbon dated (~298 ± 134 and 831 ± 87 yr BP) by Mercer and Palacios (1977) and presented as some of the first evidence for cooling in the tropics during the Little Ice Age. Recent field investigations in the QIC region focused on refining the chronology of the Huancane I moraines. In 2008, new stratigraphic sections exposed by local lake-flooding events revealed multiple layers of peat within the Huancane I moraines. In both 2008 and 2009, samples were obtained for 10Be dating of boulders on Huancane I moraines. A combination of radiocarbon and 10Be ages indicate that the Huancane I moraines were deposited by ice cap expansion after ~3800 yr BP and likely by multiple advances at approximately 1000, 600, 400, and 200 yr BP. Radiocarbon and 10Be chronologies of the Huancane I moraines are compared with the Quelccaya ice core records (Thompson et al., 1985; 1986; 2006). Accumulation data from the ice core records are interpreted to indicate a significant wet period at ~1500-1700 AD followed by a significant drought at ~1720-1860 AD. We examine ice marginal fluctuations during these times to determine influence of such events on the ice cap extent.

  2. Arctic sea-ice ridges—Safe heavens for sea-ice fauna during periods of extreme ice melt?

    Science.gov (United States)

    Gradinger, Rolf; Bluhm, Bodil; Iken, Katrin

    2010-01-01

    The abundances and distribution of metazoan within-ice meiofauna (13 stations) and under-ice fauna (12 stations) were investigated in level sea ice and sea-ice ridges in the Chukchi/Beaufort Seas and Canada Basin in June/July 2005 using a combination of ice coring and SCUBA diving. Ice meiofauna abundance was estimated based on live counts in the bottom 30 cm of level sea ice based on triplicate ice core sampling at each location, and in individual ice chunks from ridges at four locations. Under-ice amphipods were counted in situ in replicate ( N=24-65 per station) 0.25 m 2 quadrats using SCUBA to a maximum water depth of 12 m. In level sea ice, the most abundant ice meiofauna groups were Turbellaria (46%), Nematoda (35%), and Harpacticoida (19%), with overall low abundances per station that ranged from 0.0 to 10.9 ind l -1 (median 0.8 ind l -1). In level ice, low ice algal pigment concentrations (Turbellaria, Nematoda and Harpacticoida also were observed in pressure ridges (0-200 ind l -1, median 40 ind l -1), although values were highly variable and only medians of Turbellaria were significantly higher in ridge ice than in level ice. Median abundances of under-ice amphipods at all ice types (level ice, various ice ridge structures) ranged from 8 to 114 ind m -2 per station and mainly consisted of Apherusa glacialis (87%), Onisimus spp. (7%) and Gammarus wilkitzkii (6%). Highest amphipod abundances were observed in pressure ridges at depths >3 m where abundances were up to 42-fold higher compared with level ice. We propose that the summer ice melt impacted meiofauna and under-ice amphipod abundance and distribution through (a) flushing, and (b) enhanced salinity stress at thinner level sea ice (less than 3 m thickness). We further suggest that pressure ridges, which extend into deeper, high-salinity water, become accumulation regions for ice meiofauna and under-ice amphipods in summer. Pressure ridges thus might be crucial for faunal survival during periods of

  3. Comparison between GPR measurements and ultrasonic tomography with different inversion algorithms: an application to the base of an ancient Egyptian sculpture

    International Nuclear Information System (INIS)

    Sambuelli, L; Bohm, G; Capizzi, P; Cosentino, P; Cardarelli, E

    2011-01-01

    By late 2008 one of the most important pieces of the 'Museo delle Antichità Egizie' of Turin, the sculpture of the Pharaoh with god Amun, was planned to be one of the masterpieces of a travelling exhibition in Japan. The 'Fondazione Museo delle Antichità Egizie di Torino', who manages the museum, was concerned with the integrity of the base of the statue which actually presents visible signs of restoration dating back to the early 19th century. It was required to estimate the persistence of the visible fractures, to search for unknown ones and to provide information about the overall mechanical strength of the base. To tackle the first question a GPR reflection survey along three sides of the base was performed and the results were assembled in a 3D rendering. As far as the second question is concerned, two parallel, horizontal ultrasonic 2D tomograms across the base were made. We acquired, for each section, 723 ultrasonic signals corresponding to different transmitter and receiver positions. The tomographic data were inverted using four different software packages based upon different algorithms. The obtained velocity images were then compared each other, with the GPR results and with the visible fractures in the base. A critical analysis of the comparisons is finally presented

  4. Sea ice-albedo climate feedback mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, J.L.; Curry, J.A. [Univ. of Colorado, Boulder, CO (United States); Ebert, E.E. [Bureau of Meterology Research Center, Melbourne (Australia)

    1995-02-01

    The sea ice-albedo feedback mechanism over the Arctic Ocean multiyear sea ice is investigated by conducting a series of experiments using several one-dimensional models of the coupled sea ice-atmosphere system. In its simplest form, ice-albedo feedback is thought to be associated with a decrease in the areal cover of snow and ice and a corresponding increase in the surface temperature, further decreasing the area cover of snow and ice. It is shown that the sea ice-albedo feedback can operate even in multiyear pack ice, without the disappearance of this ice, associated with internal processes occurring within the multiyear ice pack (e.g., duration of the snow cover, ice thickness, ice distribution, lead fraction, and melt pond characteristics). The strength of the ice-albedo feedback mechanism is compared for several different thermodynamic sea ice models: a new model that includes ice thickness distribution., the Ebert and Curry model, the Mayjut and Untersteiner model, and the Semtner level-3 and level-0 models. The climate forcing is chosen to be a perturbation of the surface heat flux, and cloud and water vapor feedbacks are inoperative so that the effects of the sea ice-albedo feedback mechanism can be isolated. The inclusion of melt ponds significantly strengthens the ice-albedo feedback, while the ice thickness distribution decreases the strength of the modeled sea ice-albedo feedback. It is emphasized that accurately modeling present-day sea ice thickness is not adequate for a sea ice parameterization; the correct physical processes must be included so that the sea ice parameterization yields correct sensitivities to external forcing. 22 refs., 6 figs., 1 tab.

  5. City under the Ice

    DEFF Research Database (Denmark)

    Nielsen, Kristian Hvidtfelt

    : The public image of Camp Century was one of technological comfort and military-scientific control. Amidst the raging Cold War and up against the harsh environment, the construction of the camp would prove to the public that the combined forces of the US military-technology-science complex would prevail......This paper uses Paul Edwards’ closed world metaphor to understand US involvement in Greenland during the Cold War. Closed worlds mark military-techno-scientific geographies of conflict: They refer to sealed techno-spaces of observation, containment, and control, but also to the settings in which....... However, the military logic of Camp Century was self-referential and closed in the sense that the very idea of constructing the city under ice emerged from Cold War strategy. The closed world of Camp Century established a temporary boundary between, on the one hand, the comfortable space controlled by US...

  6. Ice-skating injuries.

    Science.gov (United States)

    Williamson, D M; Lowdon, I M

    1986-05-01

    The range of injuries sustained at an ice-rink and presented to an Accident Service department is described. A total of 203 patients with 222 injuries presented themselves during a 2-month period. There were 103 noteworthy injuries, including 61 fractures, 2 dislocations and 2 severed tendons, but the commonest injuries were wounds, sprains and bruises. Beginners appear to be more prone to injury than experienced skaters. In addition to using well-fitting skate-boots to protect the ankle, some injuries could be avoided by wearing elbow and knee pads, and a thick pair of gloves. The number of injuries compared with the total number of skaters was small but produced a noteworthy increase in the workload of the Accident Service.

  7. A model of the ice-d electron metal interface

    International Nuclear Information System (INIS)

    Painter, K.R.; Grout, P.J.; March, N.H.; Tosi, M.P.

    1981-10-01

    A qualitative explanation of the different orientations of the growth of ice on Pt (111) and Ag (111) surfaces is proposed. Other physical consequences which follow are discussed and experiments are suggested to test these. (author)

  8. VT Ice Damage Assessment from the 1998 Ice Storm

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) This dataset (ICEDAMAG98) depicts the extent and severity of tree damage caused by the 1998 ice storm, which resulted in extensive tree damage in...

  9. Influence of winter sea-ice motion on summer ice cover in the Arctic

    Directory of Open Access Journals (Sweden)

    Noriaki Kimura

    2013-11-01

    Full Text Available Summer sea-ice cover in the Arctic varies largely from year to year owing to several factors. This study examines one such factor, the relationship between interannual difference in winter ice motion and ice area in the following summer. A daily-ice velocity product on a 37.5-km resolution grid is prepared using the satellite passive microwave sensor Advanced Microwave Scanning Radiometer—Earth Observing System data for the nine years of 2003–2011. Derived daily-ice motion reveals the dynamic modification of the winter ice cover. The winter ice divergence/convergence is strongly related to the summer ice cover in some regions; the correlation coefficient between the winter ice convergence and summer ice area ranges between 0.5 and 0.9 in areas with high interannual variability. This relation implies that the winter ice redistribution controls the spring ice thickness and the summer ice cover.

  10. 14 CFR 23.1419 - Ice protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ice protection. 23.1419 Section 23.1419... Ice protection. If certification with ice protection provisions is desired, compliance with the... performed to establish, on the basis of the airplane's operational needs, the adequacy of the ice protection...

  11. Airframe Icing Research Gaps: NASA Perspective

    Science.gov (United States)

    Potapczuk, Mark

    2009-01-01

    qCurrent Airframe Icing Technology Gaps: Development of a full 3D ice accretion simulation model. Development of an improved simulation model for SLD conditions. CFD modeling of stall behavior for ice-contaminated wings/tails. Computational methods for simulation of stability and control parameters. Analysis of thermal ice protection system performance. Quantification of 3D ice shape geometric characteristics Development of accurate ground-based simulation of SLD conditions. Development of scaling methods for SLD conditions. Development of advanced diagnostic techniques for assessment of tunnel cloud conditions. Identification of critical ice shapes for aerodynamic performance degradation. Aerodynamic scaling issues associated with testing scale model ice shape geometries. Development of altitude scaling methods for thermal ice protections systems. Development of accurate parameter identification methods. Measurement of stability and control parameters for an ice-contaminated swept wing aircraft. Creation of control law modifications to prevent loss of control during icing encounters. 3D ice shape geometries. Collection efficiency data for ice shape geometries. SLD ice shape data, in-flight and ground-based, for simulation verification. Aerodynamic performance data for 3D geometries and various icing conditions. Stability and control parameter data for iced aircraft configurations. Thermal ice protection system data for simulation validation.

  12. Review of Anti-Icing/Ice Release Systems

    Science.gov (United States)

    2014-01-29

    walkways, and superstructure which the US Navy has shown 1 for a Green Arctic Patrol Vessel can be supplied by waste heat recovery from engine...adhesion strength than the ice does, thus facilitating shear. It has been found that such treatments depend on the chemical nature and condition of...application. • Ablative or Depletion Coatings: where the coating fails cohesively as ice is sheared away, or where low surface energy or oily additives

  13. Winter sea ice export from the Laptev Sea preconditions the local summer sea ice cover and fast ice decay

    Directory of Open Access Journals (Sweden)

    P. Itkin

    2017-10-01

    Full Text Available Ice retreat in the eastern Eurasian Arctic is a consequence of atmospheric and oceanic processes and regional feedback mechanisms acting on the ice cover, both in winter and summer. A correct representation of these processes in numerical models is important, since it will improve predictions of sea ice anomalies along the Northeast Passage and beyond. In this study, we highlight the importance of winter ice dynamics for local summer sea ice anomalies in thickness, volume and extent. By means of airborne sea ice thickness surveys made over pack ice areas in the south-eastern Laptev Sea, we show that years of offshore-directed sea ice transport have a thinning effect on the late-winter sea ice cover. To confirm the preconditioning effect of enhanced offshore advection in late winter on the summer sea ice cover, we perform a sensitivity study using a numerical model. Results verify that the preconditioning effect plays a bigger role for the regional ice extent. Furthermore, they indicate an increase in volume export from the Laptev Sea as a consequence of enhanced offshore advection, which has far-reaching consequences for the entire Arctic sea ice mass balance. Moreover we show that ice dynamics in winter not only preconditions local summer ice extent, but also accelerate fast-ice decay.

  14. Loss of sea ice in the Arctic.

    Science.gov (United States)

    Perovich, Donald K; Richter-Menge, Jacqueline A

    2009-01-01

    The Arctic sea ice cover is in decline. The areal extent of the ice cover has been decreasing for the past few decades at an accelerating rate. Evidence also points to a decrease in sea ice thickness and a reduction in the amount of thicker perennial sea ice. A general global warming trend has made the ice cover more vulnerable to natural fluctuations in atmospheric and oceanic forcing. The observed reduction in Arctic sea ice is a consequence of both thermodynamic and dynamic processes, including such factors as preconditioning of the ice cover, overall warming trends, changes in cloud coverage, shifts in atmospheric circulation patterns, increased export of older ice out of the Arctic, advection of ocean heat from the Pacific and North Atlantic, enhanced solar heating of the ocean, and the ice-albedo feedback. The diminishing Arctic sea ice is creating social, political, economic, and ecological challenges.

  15. Charge Transfer Scheme for Atmospheric Ice Sensing

    Directory of Open Access Journals (Sweden)

    Umair Najeeb MUGHAL

    2015-01-01

    Full Text Available The atmospheric icing parameters are being measured nowadays with the aid of more customized yet limited commercial equipment. The parameters include atmospheric ice detection, icing load and icing rate. The robustness of such equipment is usually under scrutiny when it comes to cold/harsh environment operations. This phenomenon was experienced consistently by the atmospheric Icing Research Team at Narvik University College during data retrieval exercises from its atmospheric icing stations installed at Fargnesfjellet during 2012-13. In this paper it is aimed to address the potential feasibility to produce a robust hardware addressing the icing measurements signals, which includes instrumentation hardware giving icing indications, icing type and de- icing rate measurements in a single platform (not commercially available till date.

  16. Greenland Ice Sheet Mass Balance

    Science.gov (United States)

    Reeh, N.

    1984-01-01

    Mass balance equation for glaciers; areal distribution and ice volumes; estimates of actual mass balance; loss by calving of icebergs; hydrological budget for Greenland; and temporal variations of Greenland mass balance are examined.

  17. Sticking properties of ice grains

    Directory of Open Access Journals (Sweden)

    Jongmanns M.

    2017-01-01

    Full Text Available We study the size dependence of pull-off forces of water ice in laboratory experiments and numerical simulations. To determine the pull-off force in our laboratory experiments, we use a liquid nitrogen cooled centrifuge. Depending on its rotation frequency, spherical ice grains detach due to the centrifugal force which is related to the adhesive properties. Numerical simulations are conducted by means of molecular dynamics simulations of hexagonal ice using a standard coarse-grained water potential. The pull-off force of a single contact between two spherical ice grains is measured due to strain controlled simulations. Both, the experimental study and the simulations reveal a dependence between the pull-off force and the (reduced particle radii, which differ significantly from the linear dependence of common contact theories.

  18. Sticking properties of ice grains

    Science.gov (United States)

    Jongmanns, M.; Kumm, M.; Wurm, G.; Wolf, D. E.; Teiser, J.

    2017-06-01

    We study the size dependence of pull-off forces of water ice in laboratory experiments and numerical simulations. To determine the pull-off force in our laboratory experiments, we use a liquid nitrogen cooled centrifuge. Depending on its rotation frequency, spherical ice grains detach due to the centrifugal force which is related to the adhesive properties. Numerical simulations are conducted by means of molecular dynamics simulations of hexagonal ice using a standard coarse-grained water potential. The pull-off force of a single contact between two spherical ice grains is measured due to strain controlled simulations. Both, the experimental study and the simulations reveal a dependence between the pull-off force and the (reduced) particle radii, which differ significantly from the linear dependence of common contact theories.

  19. Radiative properties of ice clouds

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, D.L.; Koracin, D.; Carter, E. [Desert Research Institute, Reno, NV (United States)

    1996-04-01

    A new treatment of cirrus cloud radiative properties has been developed, based on anomalous diffraction theory (ADT), which does not parameterize size distributions in terms of an effective radius. Rather, is uses the size distribution parameters directly, and explicitly considers the ice particle shapes. There are three fundamental features which characterize this treatment: (1) the ice path radiation experiences as it travels through an ice crystal is parameterized, (2) only determines the amount of radiation scattered and absorbed, and (3) as in other treatments, the projected area of the size distribution is conserved. The first two features are unique to this treatment, since it does not convert the ice particles into equivalent volume or area spheres in order to apply Mie theory.

  20. Microfabricated Ice-Detection Sensor

    National Research Council Canada - National Science Library

    DeAnna, Russell

    1997-01-01

    .... The sensor is capable of distinguishing between an ice covered and a clean surface. It employs a bulk micromachined wafer with a 7 micrometers thick, boron doped, silicon diaphragm which serves as one plate of a parallel plate capacitor...

  1. 2006 Program of Study: Ice

    National Research Council Canada - National Science Library

    Balmforth, Neil J; Wettlaufer, John S; Worster, Grae

    2007-01-01

    .... Towards the end of Grae's lectures, we also held the 2006 GFD Public Lecture. This was given by Greg Dash of the University of Washington, on matters of ice physics and a well known popularization...

  2. Let's Make Metric Ice Cream

    Science.gov (United States)

    Zimmerman, Marianna

    1975-01-01

    Describes a classroom activity which involved sixth grade students in a learning situation including making ice cream, safety procedures in a science laboratory, calibrating a thermometer, using metric units of volume and mass. (EB)

  3. Autonomous Sea-Ice Thickness Survey

    Science.gov (United States)

    2016-06-01

    the conductivity of an infinitely thick slab of sea ice. Ice thickness, Hice, is then obtained by subtracting the height of the ...Thickness Survey of Sea Ice Runway” ERDC/CRREL SR-16-4 ii Abstract We conducted an autonomous survey of sea -ice thickness using the Polar rover Yeti...efficiency relative to manual surveys routinely con- ducted to assess the safety of roads and runways constructed on the sea ice. Yeti executed the

  4. Multiscale Models of Melting Arctic Sea Ice

    Science.gov (United States)

    2014-09-30

    Sea ice reflectance or albedo , a key parameter in climate modeling, is primarily determined by melt pond and ice floe configurations. Ice - albedo ...determine their albedo - a key parameter in climate modeling. Here we explore the possibility of a conceptual sea ice climate model passing through a...bifurcation points. Ising model for melt ponds on Arctic sea ice Y. Ma, I. Sudakov, and K. M. Golden Abstract: The albedo of melting

  5. Ice sheet hydrology - a review

    Energy Technology Data Exchange (ETDEWEB)

    Jansson, Peter; Naeslund, Jens-Ove [Dept. of Physical Geography and Quaternary Geology, Stockholm Univ., Stockholm (Sweden); Rodhe, Lars [Geological Survey of Sweden, Uppsala (Sweden)

    2007-03-15

    This report summarizes the theoretical knowledge on water flow in and beneath glaciers and ice sheets and how these theories are applied in models to simulate the hydrology of ice sheets. The purpose is to present the state of knowledge and, perhaps more importantly, identify the gaps in our understanding of ice sheet hydrology. Many general concepts in hydrology and hydraulics are applicable to water flow in glaciers. However, the unique situation of having the liquid phase flowing in conduits of the solid phase of the same material, water, is not a commonly occurring phenomena. This situation means that the heat exchange between the phases and the resulting phase changes also have to be accounted for in the analysis. The fact that the solidus in the pressure-temperature dependent phase diagram of water has a negative slope provides further complications. Ice can thus melt or freeze from both temperature and pressure variations or variations in both. In order to provide details of the current understanding of water flow in conjunction with deforming ice and to provide understanding for the development of ideas and models, emphasis has been put on the mathematical treatments, which are reproduced in detail. Qualitative results corroborating theory or, perhaps more often, questioning the simplifications made in theory, are also given. The overarching problem with our knowledge of glacier hydrology is the gap between the local theories of processes and the general flow of water in glaciers and ice sheets. Water is often channelized in non-stationary conduits through the ice, features which due to their minute size relative to the size of glaciers and ice sheets are difficult to incorporate in spatially larger models. Since the dynamic response of ice sheets to global warming is becoming a key issue in, e.g. sea-level change studies, the problems of the coupling between the hydrology of an ice sheet and its dynamics is steadily gaining interest. New work is emerging

  6. Ice sheet hydrology - a review

    International Nuclear Information System (INIS)

    Jansson, Peter; Naeslund, Jens-Ove; Rodhe, Lars

    2007-03-01

    This report summarizes the theoretical knowledge on water flow in and beneath glaciers and ice sheets and how these theories are applied in models to simulate the hydrology of ice sheets. The purpose is to present the state of knowledge and, perhaps more importantly, identify the gaps in our understanding of ice sheet hydrology. Many general concepts in hydrology and hydraulics are applicable to water flow in glaciers. However, the unique situation of having the liquid phase flowing in conduits of the solid phase of the same material, water, is not a commonly occurring phenomena. This situation means that the heat exchange between the phases and the resulting phase changes also have to be accounted for in the analysis. The fact that the solidus in the pressure-temperature dependent phase diagram of water has a negative slope provides further complications. Ice can thus melt or freeze from both temperature and pressure variations or variations in both. In order to provide details of the current understanding of water flow in conjunction with deforming ice and to provide understanding for the development of ideas and models, emphasis has been put on the mathematical treatments, which are reproduced in detail. Qualitative results corroborating theory or, perhaps more often, questioning the simplifications made in theory, are also given. The overarching problem with our knowledge of glacier hydrology is the gap between the local theories of processes and the general flow of water in glaciers and ice sheets. Water is often channelized in non-stationary conduits through the ice, features which due to their minute size relative to the size of glaciers and ice sheets are difficult to incorporate in spatially larger models. Since the dynamic response of ice sheets to global warming is becoming a key issue in, e.g. sea-level change studies, the problems of the coupling between the hydrology of an ice sheet and its dynamics is steadily gaining interest. New work is emerging

  7. Endmembers of Ice Shelf Melt

    Science.gov (United States)

    Boghosian, A.; Child, S. F.; Kingslake, J.; Tedesco, M.; Bell, R. E.; Alexandrov, O.; McMichael, S.

    2017-12-01

    Studies of surface melt on ice shelves have defined a spectrum of meltwater behavior. On one end the storage of meltwater in persistent surface ponds can trigger ice shelf collapse as in the 2002 event leading to the disintegration of the Larsen B Ice Shelf. On the other, meltwater export by rivers can stabilize an ice shelf as was recently shown on the Nansen Ice Shelf. We explore this dichotomy by quantifying the partitioning between stored and transported water on two glaciers adjacent to floating ice shelves, Nimrod (Antarctica) and Peterman (Greenland). We analyze optical satellite imagery (LANDSAT, WorldView), airborne imagery (Operation IceBridge, Trimetrogon Aerial Phototography), satellite radar (Sentinel-1), and digital elevation models (DEMs) to categorize surface meltwater fate and map the evolution of ice shelf hydrology and topographic features through time. On the floating Peterman Glacier tongue a sizable river exports water to the ocean. The surface hydrology of Nimrod Glacier, geometrically similar to Peterman but with ten times shallower surface slope, is dominated by storage in surface lakes. In contrast, the Nansen has the same surface slope as Nimrod but transports water through surface rivers. Slope alone is not the sole control on ice shelf hydrology. It is essential to track the storage and transport volumes for each of these systems. To estimate water storage and transport we analyze high resolution (40 cm - 2 m) modern and historical DEMs. We produce historical (1957 onwards) DEMs with structure-from-motion photogrammetry. The DEMs are used to constrain water storage potential estimates of observed basins and water routing/transport potential. We quantify the total volume of water stored seasonally and interannually. We use the normalize difference water index to map meltwater extent, and estimate lake water depth from optical data. We also consider the role of stored water in subsurface aquifers in recharging surface water after

  8. Atmospheric Icing on Sea Structures,

    Science.gov (United States)

    1984-04-01

    results. ESTIMATION OF ICING INTENSITY Freezing process When supercooled water drops fall or move with wind, hit a structure, and freeze, the...a collision with another drop- let, with the ground, or with a structure. When a supercooled droplet hits a solid obstacle, it spreads and turns to...accretion is likely. The meteorological conditions that prevail during ship icing have been studied widely (Shektman 1968, Tabata 1968, Borisenkov and

  9. STABLE ISOTOPE GEOCHEMISTRY OF MASSIVE ICE

    Directory of Open Access Journals (Sweden)

    Yurij K. Vasil’chuk

    2016-01-01

    Full Text Available The paper summarises stable-isotope research on massive ice in the Russian and North American Arctic, and includes the latest understanding of massive-ice formation. A new classification of massive-ice complexes is proposed, encompassing the range and variabilityof massive ice. It distinguishes two new categories of massive-ice complexes: homogeneousmassive-ice complexes have a similar structure, properties and genesis throughout, whereasheterogeneous massive-ice complexes vary spatially (in their structure and properties andgenetically within a locality and consist of two or more homogeneous massive-ice bodies.Analysis of pollen and spores in massive ice from Subarctic regions and from ice and snow cover of Arctic ice caps assists with interpretation of the origin of massive ice. Radiocarbon ages of massive ice and host sediments are considered together with isotope values of heavy oxygen and deuterium from massive ice plotted at a uniform scale in order to assist interpretation and correlation of the ice.

  10. NASA Iced Aerodynamics and Controls Current Research

    Science.gov (United States)

    Addy, Gene

    2009-01-01

    This slide presentation reviews the state of current research in the area of aerodynamics and aircraft control with ice conditions by the Aviation Safety Program, part of the Integrated Resilient Aircraft Controls Project (IRAC). Included in the presentation is a overview of the modeling efforts. The objective of the modeling is to develop experimental and computational methods to model and predict aircraft response during adverse flight conditions, including icing. The Aircraft icing modeling efforts includes the Ice-Contaminated Aerodynamics Modeling, which examines the effects of ice contamination on aircraft aerodynamics, and CFD modeling of ice-contaminated aircraft aerodynamics, and Advanced Ice Accretion Process Modeling which examines the physics of ice accretion, and works on computational modeling of ice accretions. The IRAC testbed, a Generic Transport Model (GTM) and its use in the investigation of the effects of icing on its aerodynamics is also reviewed. This has led to a more thorough understanding and models, both theoretical and empirical of icing physics and ice accretion for airframes, advanced 3D ice accretion prediction codes, CFD methods for iced aerodynamics and better understanding of aircraft iced aerodynamics and its effects on control surface effectiveness.

  11. Canadian Ice Service Arctic Regional Sea Ice Charts in SIGRID-3 Format

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Canadian Ice Service (CIS) produces digital Arctic regional sea ice charts for marine navigation, climate research, and input to the Global Digital Sea Ice Data...

  12. Momentum Exchange Near Ice Keels in the Under Ice Ocean Boundary Layer

    National Research Council Canada - National Science Library

    Bleidorn, John C

    2008-01-01

    .... Understanding ice-ocean momentum exchange is important for accurate predictive ice modeling. Due to climate change, increased naval presence in the Arctic region is anticipated and ice models will become necessary for tactical and safety reasons...

  13. Meteorites, Ice, and Antarctica

    Science.gov (United States)

    Cassidy, William A.

    2003-08-01

    Bill Cassidy led meteorite recovery expeditions in the Antarctic for fifteen years and his searches have resulted in the collection of thousands of meteorite specimens from the ice. This personal account of his field experiences on the U.S. Antarctic Search for Meteorites Project reveals the influence the work has had on our understanding of the moon, Mars and the asteroid belt. Cassidy describes the hardships and dangers of fieldwork in a hostile environment, as well as the appreciation he developed for its beauty. William Cassidy is Emeritus Professor of Geology and Planetary Science at the University of Pittsburgh. He initiated the U.S. Antarctic Search for Meteorites (ANSMET) nroject and led meteorite recovery expeditions in Antarctica in1976. His name is found attached to a mineral (cassidyite), on the map of Antarctica (Cassidy Glacier), and in the Catalog of Asteroids (3382 Cassidy). Profiled in "American Men of Science," and "Who's Who in America," he is also a recipient of The Antarctic Service Medal from the United States and has published widely in Science, Meteoritics and Planetary Science, and The Journal of Geophysical Research.

  14. Fire in the ice

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, Graham

    2011-10-15

    Research is ongoing to investigate the feasibility of unlocking about 85 trillion cubic feet of pure methane gas from hydrates on Alaska's North Slope while sequestering CO2 to combat global warming. When the well reaches a depth of 2,597 feet, the wireline well logs will be registered. The well site was chosen for its multiplicity of test horizons, that is, varying porosity sandstones. The CO2 injection scheme should be tested before the hydrate experiment is carried out. Lab tests and numerical modeling developed by ConocoPhillips and the University of Bergen have demonstrated the feasibility of exchanging CH4 (methane) for CO2 in porous and permeable sandstone reservoirs. However, the challenge is that that field situation is more complex than a lab test. So a new, smaller ice pad around the well is planne, starting with a nitrogen and CO2 mix injection and adjusting the mix as the experiment progresses. Canada did not participate in this test project, because it is difficult to scale up from idealized lab-scale studies and theoretical modeling to the field scale. The U.S Gulf of Mexico also has important gas hydrates reserves which may be less expensive to research and operate.

  15. Acquisition of Ice Thickness and Ice Surface Characteristics in the Seasonal Ice Zone by CULPIS-X during the US Coast Guard’s Arctic Domain Awareness Program

    Science.gov (United States)

    2014-09-30

    OBJECTIVES • What is the volume of sea ice in the Beaufort Sea Seasonal Ice Zone (SIZ) and how does this evolve during summer as the ice edge...retreats? Recent observations suggest that the remaining ice in the Beaufort Sea is younger and thinner in recent years in part because even the oldest...surrounding ice . Recent analyses have indicated that ponds on thinner ice are often darker, accelerating the ice - albedo feedback over thin ice in summer

  16. Application of gas chromatography, mass spectrometry analysis to the study of works of art. Paint media identification in polychrome multi-material sculptures

    Energy Technology Data Exchange (ETDEWEB)

    Casoli, A.; Vizzari, M. [Parma Univ., Parma (Italy). Dipt. di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica; Cremonesi, P. [Chemist and Conservator, Cornegliano Laudense, Lodi (Italy); Palla, G. [Parma Univ., Parma (Italy). Dipt. di Chimica Organica e Industriale

    2001-12-01

    A new gas chromatographic-mass spectrometric procedure for characterizing both drying oil and proteinaceous binders in samples of painted artworks has been developed. Furthermore, a new analytical procedure for analysis of polysaccharide materials through identification of the monosaccharide constituents is proposed. The methods have been applied to characterize binding media of the different layers of the polychrome surface in the multi-material sculptures from the sanctuary of 'S. Maria delle Grazie in Mantova', Italy. It was found that animal glue was the main binder in the priming layer of all statues, whereas more complex mixtures were used in the paint layers. Generally, a drying oil was present, most often linseed oil alone or in combination with other organic binders. [Italian] Si propone una nuova procedura analitica, mediante gascromatografia/spettrometria di massa, rivolta alla caratterizzazione di oli siccativi e leganti proteici presenti in un unico campione di materiale pittorico derivante da un'opera d'arte. Si descrive, inoltre, un nuovo metodo gascromatografico per l'analisi di materiale polisaccaridico, mediante l'identificazione dei suoi componenti. I metodi analitici sono stati impiegati per la caratterizzazione del legante pittorico dei differenti strati costituenti la policromia di sculture polimateriche conservate presso il Santuario di Santa Maria delle Grazie in Mantova. E' stato riscontrato che per tutte le statue, il legante principale degli strati di preparazione del colore era colla animale, mentre , si e' osservato, inoltre, che gli strati pittorici hanno previsto, per la loro stesura, l'impiego di miscele complesse di sostanze organiche. Principalmente e' stata riscontrata la presenza di olio di lino, impiegato sia come unico legante sia in combinazione con altri.

  17. Mixed ice accretion on aircraft wings

    Science.gov (United States)

    Janjua, Zaid A.; Turnbull, Barbara; Hibberd, Stephen; Choi, Kwing-So

    2018-02-01

    Ice accretion is a problematic natural phenomenon that affects a wide range of engineering applications including power cables, radio masts, and wind turbines. Accretion on aircraft wings occurs when supercooled water droplets freeze instantaneously on impact to form rime ice or runback as water along the wing to form glaze ice. Most models to date have ignored the accretion of mixed ice, which is a combination of rime and glaze. A parameter we term the "freezing fraction" is defined as the fraction of a supercooled droplet that freezes on impact with the top surface of the accretion ice to explore the concept of mixed ice accretion. Additionally we consider different "packing densities" of rime ice, mimicking the different bulk rime densities observed in nature. Ice accretion is considered in four stages: rime, primary mixed, secondary mixed, and glaze ice. Predictions match with existing models and experimental data in the limiting rime and glaze cases. The mixed ice formulation however provides additional insight into the composition of the overall ice structure, which ultimately influences adhesion and ice thickness, and shows that for similar atmospheric parameter ranges, this simple mixed ice description leads to very different accretion rates. A simple one-dimensional energy balance was solved to show how this freezing fraction parameter increases with decrease in atmospheric temperature, with lower freezing fraction promoting glaze ice accretion.

  18. Ice nucleation activity of polysaccharides

    Science.gov (United States)

    Bichler, Magdalena; Felgitsch, Laura; Haeusler, Thomas; Seidl-Seiboth, Verena; Grothe, Hinrich

    2015-04-01

    Heterogeneous ice nucleation is an important process in the atmosphere. It shows direct impact on our climate by triggering ice cloud formation and therefore it has much influence on the radiation balance of our planet (Lohmann et al. 2002; Mishchenko et al. 1996). The process itself is not completely understood so far and many questions remain open. Different substances have been found to exhibit ice nucleation activity (INA). Due to their vast differences in chemistry and morphology it is difficult to predict what substance will make good ice nuclei and which will not. Hence simple model substances must be found and be tested regarding INA. Our work aims at gaining to a deeper understanding of heterogeneous ice nucleation. We intend to find some reference standards with defined chemistry, which may explain the mechanisms of heterogeneous ice nucleation. A particular focus lies on biological carbohydrates in regards to their INA. Biological carbohydrates are widely distributed in all kingdoms of life. Mostly they are specific for certain organisms and have well defined purposes, e.g. structural polysaccharides like chitin (in fungi and insects) and pectin (in plants), which has also water-binding properties. Since they are widely distributed throughout our biosphere and mostly safe to use for nutrition purposes, they are well studied and easily accessible, rendering them ideal candidates as proxies. In our experiments we examined various carbohydrates, like the already mentioned chitin and pectin, as well as their chemical modifications. Lohmann U.; A Glaciation Indirect Aerosol Effect Caused by Soot Aerosols; J. Geoph. Res.; Vol. 24 No.4; pp 11-1 - 11-4; 2002 Mishchenko M.I., Rossow W.B., Macke A., Lacis A. A.; Sensitivity of Cirrus Cloud Albedo, Bidirectional Reflectance and Optical Thickness Retrieval Accuracy to Ice Particle Shape, J. Geoph. Res.; Vol. 101, No D12; pp. 16,973 - 16,985; 1996

  19. Sensitivity of open-water ice growth and ice concentration evolution in a coupled atmosphere-ocean-sea ice model

    Science.gov (United States)

    Shi, Xiaoxu; Lohmann, Gerrit

    2017-09-01

    A coupled atmosphere-ocean-sea ice model is applied to investigate to what degree the area-thickness distribution of new ice formed in open water affects the ice and ocean properties. Two sensitivity experiments are performed which modify the horizontal-to-vertical aspect ratio of open-water ice growth. The resulting changes in the Arctic sea-ice concentration strongly affect the surface albedo, the ocean heat release to the atmosphere, and the sea-ice production. The changes are further amplified through a positive feedback mechanism among the Arctic sea ice, the Atlantic Meridional Overturning Circulation (AMOC), and the surface air temperature in the Arctic, as the Fram Strait sea ice import influences the freshwater budget in the North Atlantic Ocean. Anomalies in sea-ice transport lead to changes in sea surface properties of the North Atlantic and the strength of AMOC. For the Southern Ocean, the most pronounced change is a warming along the Antarctic Circumpolar Current (ACC), owing to the interhemispheric bipolar seasaw linked to AMOC weakening. Another insight of this study lies on the improvement of our climate model. The ocean component FESOM is a newly developed ocean-sea ice model with an unstructured mesh and multi-resolution. We find that the subpolar sea-ice boundary in the Northern Hemisphere can be improved by tuning the process of open-water ice growth, which strongly influences the sea ice concentration in the marginal ice zone, the North Atlantic circulation, salinity and Arctic sea ice volume. Since the distribution of new ice on open water relies on many uncertain parameters and the knowledge of the detailed processes is currently too crude, it is a challenge to implement the processes realistically into models. Based on our sensitivity experiments, we conclude a pronounced uncertainty related to open-water sea ice growth which could significantly affect the climate system sensitivity.

  20. Ice-condenser aerosol tests

    International Nuclear Information System (INIS)

    Ligotke, M.W.; Eschbach, E.J.; Winegardner, W.K.

    1991-09-01

    This report presents the results of an experimental investigation of aerosol particle transport and capture using a full-scale height and reduced-scale cross section test facility based on the design of the ice compartment of a pressurized water reactor (PWR) ice-condenser containment system. Results of 38 tests included thermal-hydraulic as well as aerosol particle data. Particle retention in the test section was greatly influenced by thermal-hydraulic and aerosol test parameters. Test-average decontamination factor (DF) ranged between 1.0 and 36 (retentions between ∼0 and 97.2%). The measured test-average particle retentions for tests without and with ice and steam ranged between DF = 1.0 and 2.2 and DF = 2.4 and 36, respectively. In order to apparent importance, parameters that caused particle retention in the test section in the presence of ice were steam mole fraction (SMF), noncondensible gas flow rate (residence time), particle solubility, and inlet particle size. Ice-basket section noncondensible flows greater than 0.1 m 3 /s resulted in stable thermal stratification whereas flows less than 0.1 m 3 /s resulted in thermal behavior termed meandering with frequent temperature crossovers between flow channels. 10 refs., 66 figs., 16 tabs

  1. ICeE an interface for C. elegans experiments.

    Science.gov (United States)

    Montañana, Frédéric; Julien, Renaud A; Vaglio, Philippe; Matthews, Lisa R; Tichit, Laurent; Ewbank, Jonathan J

    2014-01-01

    An increasing number of laboratories are using the COPAS Biosort™ to implement high-throughput approaches to tackle diverse biological problems. While providing a powerful tool for generating quantitative data, the utility of the Biosort is currently limited by the absence of resources for data management. We describe a simple electronic database designed to allow easy storage and retrieval of Biosort data for C. elegans, but that has a wide potential application for organizing electronic files and data sets. ICeE is an Open Source application. The code and accompanying documentation are freely available via the web at http://www.ciml.univ-mrs.fr/EWBANK_jonathan/software.html.

  2. Open-Source Python Modules to Estimate Level Ice Thickness from Ice Charts

    Science.gov (United States)

    Geiger, C. A.; Deliberty, T. L.; Bernstein, E. R.; Helfrich, S.

    2012-12-01

    A collaborative research effort between the University of Delaware (UD) and National Ice Center (NIC) addresses the task of providing open-source translations of sea ice stage-of-development into level ice thickness estimates on a 4km grid for the Interactive Multisensor Snow and Ice Mapping System (IMS). The characteristics for stage-of-development are quantified from remote sensing imagery with estimates of level ice thickness categories originating from World Meteorological Organization (WMO) egg coded ice charts codified since the 1970s. Conversions utilize Python scripting modules which transform electronic ice charts with WMO egg code characteristics into five level ice thickness categories, in centimeters, (0-10, 10-30, 30-70, 70-120, >120cm) and five ice types (open water, first year pack ice, fast ice, multiyear ice, and glacial ice with a reserve slot for deformed ice fractions). Both level ice thickness categories and ice concentration fractions are reported with uncertainties propagated based on WMO ice stage ranges which serve as proxy estimates for standard deviation. These products are in preparation for use by NCEP, CMC, and NAVO by 2014 based on their modeling requirements for daily products in near-real time. In addition to development, continuing research tests the value of these estimated products against in situ observations to improve both value and uncertainty estimates.

  3. Characterization of an IceTop tank for the IceCube surface extension IceVeto

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, Julian; Auffenberg, Jan; Hansmann, Bengt; Rongen, Martin; Stahlberg, Martin; Wiebusch, Christopher [III. Physikalisches Institut B, RWTH Aachen University (Germany); Collaboration: IceCube-Collaboration

    2015-07-01

    IceTop is an air-shower detector located at the South Pole on the surface above the IceCube detector. It consists of 81 detector stations with two Cherenkov tanks each. The tanks are filled with clear ice and instrumented with two photomultipliers. IceTop detects cosmic-ray induced air-showers above an energy threshold of ∝300 TeV. Muons and neutrinos from these air-showers are the main background for astrophysical neutrino searches with IceCube. The usage of IceTop to veto air-showers largely reduces this background in the field of view. To enlarge the field of view an extension of the surface detector, IceVeto, is planned. Therefore, we investigate the properties of an original IceTop tank as a laboratory reference for the development of new detection module designs. First results of these measurements are presented.

  4. Proceedings of the 19. IAHR international symposium on ice : using new technology to understand water-ice interaction

    International Nuclear Information System (INIS)

    Jasek, M.; Andrishak, R.; Siddiqui, A.

    2008-01-01

    This conference provided a venue for scientists, engineers and researchers an opportunity to expand their knowledge of water-ice interactions with reference to water resources, river and coastal hydraulics, risk analysis, energy and the environment. The the theme of new technology falls into 3 basic groups, notably measurement and instrumentation; remote sensing; and numerical simulation. The thermal regime of rivers was discussed along with ice mechanics, ice hydraulics, ice structures and modelling ice phenomena. The titles of the sessions were: river ice, glaciers and climate change; freeze-up processes on rivers and oceans; river ice-structure interactions; numerical simulations in ice engineering; river-ice break-up and ice jam formation; ice measurement; Grasse River ice evaluation; evaluation of structural ice control alternatives; remote sensing; hydropower and dam decommissioning; mechanical behaviour of river ice, ice covered flow and thermal modelling; mathematical and computer model formulations for ice friction and sea ice; ice bergs and ice navigation; ice crushing processes; sea ice and shore/structure interactions; ice properties, testing and physical modelling; ice actions on compliant structures; oil spills in ice; desalination, ice thickness and climate change; and, sea ice ridges. The conference featured 123 presentations, of which 20 have been catalogued separately for inclusion in this database. refs., tabs., figs

  5. Thermodynamic and Dynamic Aspects of Ice Nucleation

    Science.gov (United States)

    Barahona, Donifan

    2018-01-01

    It is known that ice nucleating particles (INP) immersed within supercooled droplets promote the formation of ice. Common theoretical models used to represent this process assume that the immersed particle lowers the work of ice nucleation without significantly affecting the dynamics of water in the vicinity of the particle. This is contrary to evidence showing that immersed surfaces significantly affect the viscosity and diffusivity of vicinal water. To study how this may affect ice formation this work introduces a model linking the ice nucleation rate to the modification of the dynamics and thermodynamics of vicinal water by immersed particles. It is shown that INP that significantly reduce the work of ice nucleation also pose strong limitations to the growth of the nascent ice germs. This leads to the onset of a new ice nucleation regime, called spinodal ice nucleation, where the dynamics of ice germ growth instead of the ice germ size determines the nucleation rate. Nucleation in this regime is characterized by an enhanced sensitivity to particle area and cooling rate. Comparison of the predicted ice nucleation rate against experimental measurements for a diverse set of species relevant to cloud formation suggests that spinodal ice nucleation may be common in nature.

  6. The safety band of Antarctic ice shelves

    Science.gov (United States)

    Fürst, Johannes Jakob; Durand, Gaël; Gillet-Chaulet, Fabien; Tavard, Laure; Rankl, Melanie; Braun, Matthias; Gagliardini, Olivier

    2016-05-01

    The floating ice shelves along the seaboard of the Antarctic ice sheet restrain the outflow of upstream grounded ice. Removal of these ice shelves, as shown by past ice-shelf recession and break-up, accelerates the outflow, which adds to sea-level rise. A key question in predicting future outflow is to quantify the extent of calving that might precondition other dynamic consequences and lead to loss of ice-shelf restraint. Here we delineate frontal areas that we label as `passive shelf ice’ and that can be removed without major dynamic implications, with contrasting results across the continent. The ice shelves in the Amundsen and Bellingshausen seas have limited or almost no `passive’ portion, which implies that further retreat of current ice-shelf fronts will yield important dynamic consequences. This region is particularly vulnerable as ice shelves have been thinning at high rates for two decades and as upstream grounded ice rests on a backward sloping bed, a precondition to marine ice-sheet instability. In contrast to these ice shelves, Larsen C Ice Shelf, in the Weddell Sea, exhibits a large `passive’ frontal area, suggesting that the imminent calving of a vast tabular iceberg will be unlikely to instantly produce much dynamic change.

  7. Inelastic neutron scattering of amorphous ice

    International Nuclear Information System (INIS)

    Fukazawa, Hiroshi; Ikeda, Susumu; Suzuki, Yoshiharu

    2001-01-01

    We measured the inelastic neutron scattering from high-density amorphous (HDA) and low-density amorphous (LDA) ice produced by pressurizing and releasing the pressure. We found a clear difference between the intermolecular vibrations in HDA and those in LDA ice: LDA ice has peaks at 22 and 33 meV, which are also seen in the spectrum of lattice vibrations in ice crystal, but the spectrum of HDA ice does not have these peaks. The excitation energy of librational vibrations in HDA ice is 10 meV lower than that in LDA ice. These results imply that HDA ice includes 2- and 5-coordinated hydrogen bonds that are created by breakage of hydrogen bonds and migration of water molecules into the interstitial site, while LDA ice contains mainly 4-coordinated hydrogen bonds and large cavities. Furthermore, we report the dynamical structure factor in the amorphous ice and show that LDA ice is more closely related to the ice crystal structure than to HDA ice. (author)

  8. Heavy Metal Presence in Two Different Types of Ice Cream: Artisanal Ice Cream (Italian Gelato) and Industrial Ice Cream.

    Science.gov (United States)

    Conficoni, D; Alberghini, L; Bissacco, E; Ferioli, M; Giaccone, V

    2017-03-01

    Ice cream, a popular product worldwide, is usually a milk-based product with other types of ingredients (fruit, eggs, cocoa, dried fruit, additives, and others). Different materials are used to obtain the desired taste, texture, consistency, and appearance of the final product. This study surveyed ice cream products available in Italy for heavy metals (lead, cadmium, chromium, tin, and arsenic). The differences between artisanal and industrial ice cream were also investigated because of the importance in the Italian diet and the diffusion of this ready-to-eat food. Ice cream sampling was performed between October 2010 and February 2011 in the northeast of Italy. A total of 100 samples were randomly collected from different sources: 50 industrial samples produced by 19 different brands were collected in coffee bars and supermarkets; 50 artisanal ice cream samples were gathered at nine different artisanal ice cream shops. Ten wooden sticks of industrial ice cream were analyzed in parallel to the ice cream. All samples were negative for arsenic and mercury. None of the artisanal ice cream samples were positive for lead and tin; 18% of the industrial ice cream samples were positive. All positive lead samples were higher than the legal limit stated for milk (0.02 mg/kg). All industrial ice cream samples were negative for cadmium, but cadmium was present in 10% of the artisanal ice cream samples. Chromium was found in 26% of the artisanal and in 58% of the industrial ice cream samples. The heavy metals found in the wooden sticks were different from the corresponding ice cream, pointing out the lack of cross-contamination between the products. Considering the results and the amount of ice cream consumed during the year, contamination through ice cream is a low risk for the Italian population, even though there is need for further analysis.

  9. PU-ICE Summary Information.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    The Generator Knowledge Report for the Plutonium Isentropic Compression Experiment Containment Systems (GK Report) provides information for the Plutonium Isentropic Compression Experiment (Pu- ICE) program to support waste management and characterization efforts. Attachment 3-18 presents generator knowledge (GK) information specific to the eighteenth Pu-ICE conducted in August 2015, also known as ‘Shot 18 (Aug 2015) and Pu-ICE Z-2841 (1).’ Shot 18 (Aug 2015) was generated on August 28, 2015 (1). Calculations based on the isotopic content of Shot 18 (Aug 2015) and the measured mass of the containment system demonstrate the post-shot containment system is low-level waste (LLW). Therefore, this containment system will be managed at Sandia National Laboratory/New Mexico (SNL/NM) as LLW. Attachment 3-18 provides documentation of the TRU concentration and documents the concentration of any hazardous constituents.

  10. Disorder and Quantum Spin Ice

    Science.gov (United States)

    Martin, N.; Bonville, P.; Lhotel, E.; Guitteny, S.; Wildes, A.; Decorse, C.; Ciomaga Hatnean, M.; Balakrishnan, G.; Mirebeau, I.; Petit, S.

    2017-10-01

    We report on diffuse neutron scattering experiments providing evidence for the presence of random strains in the quantum spin-ice candidate Pr2Zr2O7 . Since Pr3 + is a non-Kramers ion, the strain deeply modifies the picture of Ising magnetic moments governing the low-temperature properties of this material. It is shown that the derived strain distribution accounts for the temperature dependence of the specific heat and of the spin-excitation spectra. Taking advantage of mean-field and spin-dynamics simulations, we argue that the randomness in Pr2Zr2O7 promotes a new state of matter, which is disordered yet characterized by short-range antiferroquadrupolar correlations, and from which emerge spin-ice-like excitations. Thus, this study gives an original research route in the field of quantum spin ice.

  11. An integrated approach to the remote sensing of floating ice

    Science.gov (United States)

    Campbell, W. J.; Ramseier, R. O.; Weeks, W. F.; Gloersen, P.

    1976-01-01

    Review article on remote sensing applications to glaciology. Ice parameters sensed include: ice cover vs open water, ice thickness, distribution and morphology of ice formations, vertical resolution of ice thickness, ice salinity (percolation and drainage of brine; flushing of ice body with fresh water), first-year ice and multiyear ice, ice growth rate and surface heat flux, divergence of ice packs, snow cover masking ice, behavior of ice shelves, icebergs, lake ice and river ice; time changes. Sensing techniques discussed include: satellite photographic surveys, thermal IR, passive and active microwave studies, microwave radiometry, microwave scatterometry, side-looking radar, and synthetic aperture radar. Remote sensing of large aquatic mammals and operational ice forecasting are also discussed.

  12. Correlating Ice Cores from Quelccaya Ice Cap with Chronology from Little Ice Age Glacial Extents

    Science.gov (United States)

    Stroup, J. S.; Kelly, M. A.; Lowell, T. V.

    2010-12-01

    Proxy records indicate Southern Hemisphere climatic changes during the Little Ice Age (LIA; ~1300-1850 AD). In particular, records of change in and around the tropical latitudes require attention because these areas are sensitive to climatic change and record the dynamic interplay between hemispheres (Oerlemans, 2005). Despite this significance, relatively few records exist for the southern tropics. Here we present a reconstruction of glacial fluctuations of Quelccaya Ice Cap (QIC), Peruvian Andes, from pre-LIA up to the present day. In the Qori Kalis valley, extensive sets of moraines exist beginning with the 1963 AD ice margin (Thompson et al., 2006) and getting progressively older down valley. Several of these older moraines can be traced and are continuous with moraines in the Challpa Cocha valley. These moraines have been dated at chronology of past ice cap extents are correlated with ice core records from QIC which show an accumulation increase during ~1500-1700 AD and an accumulation decrease during ~1720-1860 AD (Thompson et al., 1985; 1986; 2006). In addition, other proxy records from Peru and the tropics are correlated with the records at QIC as a means to understand climate conditions during the LIA. This work forms the basis for future modeling of the glacial system during the LIA at QIC and for modeling of past temperature and precipitation regimes at high altitude in the tropics.

  13. Changes on the ice plain of Ice Stream B and Ross Ice Shelf

    Science.gov (United States)

    Shabtaie, Sion

    1993-01-01

    During the 1970's and 1980's, nearly 200 stations from which accurate, three dimensional position fixes have been obtained from TRANSIT satellites were occupied throughout the Ross Ice Shelf. We have transformed the elevations obtained by satellite altimetry to the same geodetic datum, and then applied a second transformation to reduce the geodetic heights to elevations above mean sea level using the GEM-10C geoidal height. On the IGY Ross Ice Shelf traverse between Oct. 1957 and Feb. 1958, an accurate method of barometric altimetry was used on a loop around the ice shelf that was directly tied to the sea at both ends of the travel route, thus providing absolute elevations. Comparisons of the two sets of data at 32 station pairs on floating ice show a mean difference of 0 +/- 1 m. The elevation data were also compared with theoretical values of elevations for a hydrostatically floating ice shelf. The mean difference between theoretical and measured values of elevations is -2 +/- 1 m.

  14. Pneumatic Tire Performance on Ice

    OpenAIRE

    Kishore Bhoopalam, Anudeep

    2015-01-01

    The evolution of vehicle safety systems, from the earliest brakes to today's accident avoidance systems, has led vehicles to have very high passenger safety. Driving on ice, though, still happens to be one of the driving conditions of low safety. A multitude of factors were identified by various studies to contribute to the complex frictional mechanism at the tire-ice interface. The tire is only force transmitting element of the vehicle, to the surface. Thus it is very essential to have in de...

  15. The formation of ice sails

    Science.gov (United States)

    Fowler, A. C.; Mayer, C.

    2017-11-01

    Debris-covered glaciers are prone to the formation of a number of supraglacial geomorphological features, and generally speaking, their upper surfaces are far from level surfaces. Some of these features are due to radiation screening or enhancing properties of the debris cover, but theoretical explanations of the consequent surface forms are in their infancy. In this paper we consider a theoretical model for the formation of "ice sails", which are regularly spaced bare ice features which are found on debris-covered glaciers in the Karakoram.

  16. Continuous Chemistry in Ice Cores

    DEFF Research Database (Denmark)

    Kjær, Helle Astrid

    on parameters involved in the study of photolysis as a source of in situ CO2. The concentration of organic substances in Greenland ice is poorly known due to their low levels and the fact that only a few studies evaluate the concentrations of specific organic compounds. Light does not penetrate deep...... depth was found as a function of wavelength. Further, by computational chemistry hybrid density functional methods (DFT), the four most common conformers of pyruvic acid were investigated in both gas, water and ice using the DFT model CAM-B3LYP with dielectric medium methods. A de rease of the energy...

  17. Greenland Radar Ice Sheet Thickness Measurements

    Data.gov (United States)

    National Aeronautics and Space Administration — Two 150-MHz coherent radar depth sounders were developed and flown over the Greenland ice sheet to obtain ice thickness measurements in support of PARCA...

  18. IceBridge Mission Flight Reports

    Data.gov (United States)

    National Aeronautics and Space Administration — The IceBridge Mission Flight Reports data set contains flight reports from NASA Operation IceBridge Greenland, Arctic, Antarctic, and Alaska missions. Flight reports...

  19. Arctic Landfast Sea Ice 1953-1998

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The files in this data set contain landfast sea ice data (monthly means) gathered from both Russian Arctic and Antarctic Research Institute (AARI) and Canadian Ice...

  20. Global Lake and River Ice Phenology Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Lake and River Ice Phenology Database contains freeze and thaw/breakup dates as well as other descriptive ice cover data for 865 lakes and rivers in the...

  1. Southern Hemisphere Ice Limits, 1973-1978

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Weekly Southern Ocean ice limits, have been digitized from U.S. Navy Fleet Weather Facility ice charts, at the Max-Planck Institut fur Meteorologie, Hamburg....

  2. History of sea ice in the Arctic

    DEFF Research Database (Denmark)

    Polyak, Leonid; Alley, Richard B.; Andrews, John T.

    2010-01-01

    Arctic sea-ice extent and volume are declining rapidly. Several studies project that the Arctic Ocean may become seasonally ice-free by the year 2040 or even earlier. Putting this into perspective requires information on the history of Arctic sea-ice conditions through the geologic past. This inf......Arctic sea-ice extent and volume are declining rapidly. Several studies project that the Arctic Ocean may become seasonally ice-free by the year 2040 or even earlier. Putting this into perspective requires information on the history of Arctic sea-ice conditions through the geologic past...... Optimum, and consistently covered at least part of the Arctic Ocean for no less than the last 13–14 million years. Ice was apparently most widespread during the last 2–3 million years, in accordance with Earth’s overall cooler climate. Nevertheless, episodes of considerably reduced sea ice or even...

  3. Ice sheet anisotropy measured with polarimetric ice sounding radar

    DEFF Research Database (Denmark)

    Dall, Jørgen

    2010-01-01

    For polar ice sheets, valuable stress and strain information can be deduced from crystal orientation fabrics (COF) and their prevailing c-axis alignment. Polarimetric radio echo sounding is a promising technique to measure the anisotropic electromagnetic propagation and reflection properties asso...

  4. Seasonal ice dynamics of the Northeast Greenland Ice Stream

    DEFF Research Database (Denmark)

    Vijay, Saurabh; Khan, Shfaqat Abbas; Simonsen, Sebastian Bjerregaard

    2018-01-01

    and temporal details. This study focus on the Northeast Greenland Ice Stream (NEGIS), which consists of three main outlets, 79 North glacier (79N), Zachariae Isstrøm (ZI) and Storstrømmen Glacier (SG). While both 79 North and Storstrømmen have floating tongues, Zachariae Isstrøm is mostly grounded...

  5. Delicious ice cream, why does salt thaw ice?

    Science.gov (United States)

    Bagnoli, Franco

    2016-03-01

    Plain Awful is an imaginary valley on the Andes populated by a highly-imitative, cubical people for which the most criminal offence is to exhibit round objects. The duck family (Scrooge, Donald and nephews) are teaming against Scrooge's worst enemy, Flintheart Glomgold, trying to buy the famous Plain Awful square eggs. Inadvertently, Scrooge violates the taboo, showing his Number One Dime, and is imprisoned in the stone quarries. He can be released only after the presentation of an ice cream soda to the President of Plain Awful. Donald and his nephews fly with Flintheart to deliver it, but Scrooge's enemy, of course, betrays the previous agreement after getting the ice cream, forcing the ducks into making an emergence replacement on the spot. Using dried milk, sugar and chocolate from their ration packs, plus some snow and salt for cooling they are able make the ice cream, and after dressing it with the carbonated water from a fire extinguisher they finally manage to produce the desired dessert. This comic may serve as an introduction to the "mysterious" phenomenon that added salt melts the ice and, even more surprising, does it by lowering the temperature of the mixture.

  6. Got Ice? Teaching Ice-Skating as a Lifelong Activity

    Science.gov (United States)

    Tarkinton, Brenda C.; Karp, Grace Goc

    2010-01-01

    With today's focus on the importance of lifelong physical activity, educators are increasingly offering a variety of such activities in their classes, as well as in before- and after-school programs. This article describes the benefits of offering ice skating as a challenging and rewarding lifetime activity, either before or after school or in…

  7. Seasonal Ice Zone Reconnaissance Surveys Coordination

    Science.gov (United States)

    2016-03-30

    Chukchi sea seasonal sea ice zone (SIZ) utilizing US Coast Guard Arctic Domain Awareness ( ADA ) flights of opportunity in the summers of 2012- 2014. In...measurements across the Beaufort-Chukchi sea seasonal sea ice zone (SIZ) utilizing US Coast Guard Arctic Domain Awareness ( ADA ) flights of...such, it contains the full range of positions of the marginal ice zone (MIZ) where sea ice interacts with open water. In addition to SIZRS

  8. Antarctic krill under sea ice: elevated abundance in a narrow band just south of ice edge.

    Science.gov (United States)

    Brierley, Andrew S; Fernandes, Paul G; Brandon, Mark A; Armstrong, Frederick; Millard, Nicholas W; McPhail, Steven D; Stevenson, Peter; Pebody, Miles; Perrett, James; Squires, Mark; Bone, Douglas G; Griffiths, Gwyn

    2002-03-08

    We surveyed Antarctic krill (Euphausia superba) under sea ice using the autonomous underwater vehicle Autosub-2. Krill were concentrated within a band under ice between 1 and 13 kilometers south of the ice edge. Within this band, krill densities were fivefold greater than that of open water. The under-ice environment has long been considered an important habitat for krill, but sampling difficulties have previously prevented direct observations under ice over the scale necessary for robust krill density estimation. Autosub-2 enabled us to make continuous high-resolution measurements of krill density under ice reaching 27 kilometers beyond the ice edge.

  9. An Ice Protection and Detection Systems Manufacturer's Perspective

    Science.gov (United States)

    Sweet, Dave

    2009-01-01

    Accomplishments include: World Class Aircraft Icing Research Center and Facility. Primary Sponsor/Partner - Aircraft Icing Consortia/Meetings. Icing Research Tunnel. Icing Test Aircraft. Icing Codes - LEWICE/Scaling, et al. Development of New Technologies (SBIR, STTR, et al). Example: Look Ahead Ice Detection. Pilot Training Materials. Full Cooperation with Academia, Government and Industry.

  10. Constraining ice sheet history in the Weddell Sea, West Antarctica, using ice fabric at Korff Ice Rise

    Science.gov (United States)

    Brisbourne, A.; Smith, A.; Kendall, J. M.; Baird, A. F.; Martin, C.; Kingslake, J.

    2017-12-01

    The grounding history of ice rises (grounded area of independent flow regime within a floating ice shelf) can be used to constrain large scale ice sheet history: ice fabric, resulting from the preferred orientation of ice crystals due to the stress regime, can be used to infer this grounding history. With the aim of measuring the present day ice fabric at Korff Ice Rise, West Antarctica, a multi-azimuth wide-angle seismic experiment was undertaken. Three wide-angle common-midpoint gathers were acquired centred on the apex of the ice rise, at azimuths of 60 degrees to one another, to measure variation in seismic properties with offset and azimuth. Both vertical and horizontal receivers were used to record P and S arrivals including converted phases. Measurements of the variation with offset and azimuth of seismic traveltimes, seismic attenuation and shear wave splitting have been used to quantify seismic anisotropy in the ice column. The observations cannot be reproduced using an isotropic ice column model. Anisotropic ray tracing has been used to test likely models of ice fabric by comparison with the data. A model with a weak girdle fabric overlying a strong cluster fabric provides the best fit to the observations. Fabric of this nature is consistent with Korff Ice Rise having been stable for the order of 10,000 years without any ungrounding or significant change in the ice flow configuration across the ice rise for this period. This observation has significant implications for the ice sheet history of the Weddell Sea sector.

  11. Development of a Capacitive Ice Sensor to Measure Ice Growth in Real Time

    Directory of Open Access Journals (Sweden)

    Xiang Zhi

    2015-03-01

    Full Text Available This paper presents the development of the capacitive sensor to measure the growth of ice on a fuel pipe surface in real time. The ice sensor consists of pairs of electrodes to detect the change in capacitance and a thermocouple temperature sensor to examine the ice formation situation. In addition, an environmental chamber was specially designed to control the humidity and temperature to simulate the ice formation conditions. From the humidity, a water film is formed on the ice sensor, which results in an increase in capacitance. Ice nucleation occurs, followed by the rapid formation of frost ice that decreases the capacitance suddenly. The capacitance is saturated. The developed ice sensor explains the ice growth providing information about the icing temperature in real time.

  12. Development of a capacitive ice sensor to measure ice growth in real time.

    Science.gov (United States)

    Zhi, Xiang; Cho, Hyo Chang; Wang, Bo; Ahn, Cheol Hee; Moon, Hyeong Soon; Go, Jeung Sang

    2015-03-19

    This paper presents the development of the capacitive sensor to measure the growth of ice on a fuel pipe surface in real time. The ice sensor consists of pairs of electrodes to detect the change in capacitance and a thermocouple temperature sensor to examine the ice formation situation. In addition, an environmental chamber was specially designed to control the humidity and temperature to simulate the ice formation conditions. From the humidity, a water film is formed on the ice sensor, which results in an increase in capacitance. Ice nucleation occurs, followed by the rapid formation of frost ice that decreases the capacitance suddenly. The capacitance is saturated. The developed ice sensor explains the ice growth providing information about the icing temperature in real time.

  13. Balance of the West Antarctic Ice Sheet

    Science.gov (United States)

    2002-01-01

    For several decades, measurements of the West Antarctic Ice Sheet showed it to be retreating rapidly. But new data derived from satellite-borne radar sensors show the ice sheet to be growing. Changing Antarctic ice sheets remains an area of high scientific interest, particularly in light of recent global warming concerns. These new findings are significant because scientists estimate that sea level would rise 5-6 meters (16-20 feet) if the ice sheet collapsed into the sea. Do these new measurements signal the end of the ice sheet's 10,000-year retreat? Or, are these new satellite data simply much more accurate than the sparse ice core and surface measurements that produced the previous estimates? Another possibility is that the ice accumulation may simply indicate that the ice sheet naturally expands and retreats in regular cycles. Cryologists will grapple with these questions, and many others, as they examine the new data. The image above depicts the region of West Antarctica where scientists measured ice speed. The fast-moving central ice streams are shown in red. Slower tributaries feeding the ice streams are shown in blue. Green areas depict slow-moving, stable areas. Thick black lines depict the areas that collect snowfall to feed their respective ice streams. Reference: Ian Joughin and Slawek Tulaczyk Science Jan 18 2002: 476-480. Image courtesy RADARSAT Antarctic Mapping Project

  14. CICE, The Los Alamos Sea Ice Model

    Energy Technology Data Exchange (ETDEWEB)

    2017-05-12

    The Los Alamos sea ice model (CICE) is the result of an effort to develop a computationally efficient sea ice component for a fully coupled atmosphere–land–ocean–ice global climate model. It was originally designed to be compatible with the Parallel Ocean Program (POP), an ocean circulation model developed at Los Alamos National Laboratory for use on massively parallel computers. CICE has several interacting components: a vertical thermodynamic model that computes local growth rates of snow and ice due to vertical conductive, radiative and turbulent fluxes, along with snowfall; an elastic-viscous-plastic model of ice dynamics, which predicts the velocity field of the ice pack based on a model of the material strength of the ice; an incremental remapping transport model that describes horizontal advection of the areal concentration, ice and snow volume and other state variables; and a ridging parameterization that transfers ice among thickness categories based on energetic balances and rates of strain. It also includes a biogeochemical model that describes evolution of the ice ecosystem. The CICE sea ice model is used for climate research as one component of complex global earth system models that include atmosphere, land, ocean and biogeochemistry components. It is also used for operational sea ice forecasting in the polar regions and in numerical weather prediction models.

  15. On the origin of the ice ages

    NARCIS (Netherlands)

    Oerlemans, J.

    1984-01-01

    Ice sheet dynamics provide a possible explanation for the 100 kyr power in climatic records. Some numerical experiments presented here show that even the transition from an essentially ice-free earth to a glacial can be produced by a northern hemisphere ice-sheet model, provided that a

  16. 14 CFR 29.1419 - Ice protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ice protection. 29.1419 Section 29.1419... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Safety Equipment § 29.1419 Ice protection. (a) To obtain... of the ice protection system for the various components of the rotorcraft. (c) In addition to the...

  17. 14 CFR 25.1419 - Ice protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ice protection. 25.1419 Section 25.1419... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Safety Equipment § 25.1419 Ice protection. If the...) An analysis must be performed to establish that the ice protection for the various components of the...

  18. 14 CFR 27.1419 - Ice protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ice protection. 27.1419 Section 27.1419... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Safety Equipment § 27.1419 Ice protection. (a) To obtain..., the adequacy of the ice protection system for the various components of the rotorcraft. (c) In...

  19. Plant ice-binding (antifreeze) proteins

    Science.gov (United States)

    Proteins that determine the temperature at which ice crystals will form in water-based solutions in cells and tissues, that bind to growing ice crystals, thus affecting their size, and that impact ice re-crystallization have been widely-documented and studied in many plant, bacterial, fungal, insect...

  20. Tree recovery from ice storm injury

    Science.gov (United States)

    Kevin T. Smith

    2015-01-01

    Ice storms are part of nature, particularly in northeastern North America. The combination of air and surface temperatures, precipitation, and wind that result in damaging layers of ice is very specific, occurring infrequently at any given location. Across the region however, damaging ice is formed in fragmented areas every year. Occasionally as in December 2013 and...

  1. Glacial Cycles and ice-sheet modelling

    NARCIS (Netherlands)

    Oerlemans, J.

    1982-01-01

    An attempt is made to simulate the Pleistocene glacial cycles with a numerical model of the Northern Hemisphere ice sheets. This model treats the vertically-integrated ice flow along a meridian, including computation of bedrock adjustment and temperature distribution in the ice. Basal melt water is

  2. Ice targets for use at NTOF

    International Nuclear Information System (INIS)

    Mercer, D.J.

    1992-12-01

    This report describes ice targets which were used during an experiment at the Neutron Time of Flight facility (NTOF) at LAMPF. Reasons for using the ice targets are given, and the construction, refrigeration system, and target preparation are detailed. Results of the research using these ice targets will be published at a later date

  3. 21 CFR 135.160 - Water ices.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Water ices. 135.160 Section 135.160 Food and Drugs... CONSUMPTION FROZEN DESSERTS Requirements for Specific Standardized Frozen Desserts § 135.160 Water ices. (a) Description. Water ices are the foods each of which is prepared from the same ingredients and in the same...

  4. Arctic multiyear ice classification and summer ice cover using passive microwave satellite data

    Science.gov (United States)

    Comiso, J. C.

    1990-08-01

    The ability to classify and monitor Arctic multiyear sea ice cover using multispectral passive microwave data is studied. Sea ice concentration maps during several summer minima have been analyzed to obtain estimates of ice surviving the summer. The results are compared with multiyear ice concentrations derived from data the following winter, using an algorithm that assumes a certain emissivity for multiyear ice. The multiyear ice cover inferred from the winter data is approximately 25 to 40% less than the summer ice cover minimum, suggesting that even during winter when the emissivity of sea ice is most stable, passive microwave data may account for only a fraction of the total multiyear ice cover. The difference of about 2×106 km2 is considerably more than estimates of advection through Fram Strait during the intervening period. It appears that as in the Antarctic, some multiyear ice floes in the Arctic, especially those near the summer marginal ice zone, have first-year ice or intermediate signatures in the subsequent winter. A likely mechanism for this is the intrusion of seawater into the snow-ice interface, which often occurs near the marginal ice zone or in areas where snow load is heavy. Spatial variations in melt and melt ponding effects also contribute to the complexity of the microwave emissivity of multiyear ice. Hence the multiyear ice data should be studied in conjunction with the previous summer ice data to obtain a more complete characterization of the state of the Arctic ice cover. The total extent and actual areas of the summertime Arctic pack ice were estimated to be 8.4×106 km2 and 6.2×106 km2, respectively, and exhibit small interannual variability during the years 1979 through 1985, suggesting a relatively stable ice cover.

  5. Airfields on Antarctic Glacier Ice

    Science.gov (United States)

    1989-12-01

    that depends on compacting the thin 3350 true. There was also a crosswind runway snow cover on the hard ice. aligned with the storm wind direction. No...expire onl 31 December 1991.) flights. It Is suggested that the USAP should adopt tile The place known to us as lte Peg .-asus site can concept of

  6. Medical ice slurry production device

    Science.gov (United States)

    Kasza, Kenneth E [Palos Park, IL; Oras, John [Des Plaines, IL; Son, HyunJin [Naperville, IL

    2008-06-24

    The present invention relates to an apparatus for producing sterile ice slurries for medical cooling applications. The apparatus is capable of producing highly loaded slurries suitable for delivery to targeted internal organs of a patient, such as the brain, heart, lungs, stomach, kidneys, pancreas, and others, through medical size diameter tubing. The ice slurry production apparatus includes a slurry production reservoir adapted to contain a volume of a saline solution. A flexible membrane crystallization surface is provided within the slurry production reservoir. The crystallization surface is chilled to a temperature below a freezing point of the saline solution within the reservoir such that ice particles form on the crystallization surface. A deflector in the form of a reciprocating member is provided for periodically distorting the crystallization surface and dislodging the ice particles which form on the crystallization surface. Using reservoir mixing the slurry is conditioned for easy pumping directly out of the production reservoir via medical tubing or delivery through other means such as squeeze bottles, squeeze bags, hypodermic syringes, manual hand delivery, and the like.

  7. Modeling and Grid Generation of Iced Airfoils

    Science.gov (United States)

    Vickerman, Mary B.; Baez, Marivell; Braun, Donald C.; Hackenberg, Anthony W.; Pennline, James A.; Schilling, Herbert W.

    2007-01-01

    SmaggIce Version 2.0 is a software toolkit for geometric modeling and grid generation for two-dimensional, singleand multi-element, clean and iced airfoils. A previous version of SmaggIce was described in Preparing and Analyzing Iced Airfoils, NASA Tech Briefs, Vol. 28, No. 8 (August 2004), page 32. To recapitulate: Ice shapes make it difficult to generate quality grids around airfoils, yet these grids are essential for predicting ice-induced complex flow. This software efficiently creates high-quality structured grids with tools that are uniquely tailored for various ice shapes. SmaggIce Version 2.0 significantly enhances the previous version primarily by adding the capability to generate grids for multi-element airfoils. This version of the software is an important step in streamlining the aeronautical analysis of ice airfoils using computational fluid dynamics (CFD) tools. The user may prepare the ice shape, define the flow domain, decompose it into blocks, generate grids, modify/divide/merge blocks, and control grid density and smoothness. All these steps may be performed efficiently even for the difficult glaze and rime ice shapes. Providing the means to generate highly controlled grids near rough ice, the software includes the creation of a wrap-around block (called the "viscous sublayer block"), which is a thin, C-type block around the wake line and iced airfoil. For multi-element airfoils, the software makes use of grids that wrap around and fill in the areas between the viscous sub-layer blocks for all elements that make up the airfoil. A scripting feature records the history of interactive steps, which can be edited and replayed later to produce other grids. Using this version of SmaggIce, ice shape handling and grid generation can become a practical engineering process, rather than a laborious research effort.

  8. Ice formation and growth shape bacterial community structure in Baltic Sea drift ice.

    Science.gov (United States)

    Eronen-Rasimus, Eeva; Lyra, Christina; Rintala, Janne-Markus; Jürgens, Klaus; Ikonen, Vilma; Kaartokallio, Hermanni

    2015-02-01

    Drift ice, open water and under-ice water bacterial communities covering several developmental stages from open water to thick ice were studied in the northern Baltic Sea. The bacterial communities were assessed with 16S rRNA gene terminal-restriction fragment length polymorphism and cloning, together with bacterial abundance and production measurements. In the early stages, open water and pancake ice were dominated by Alphaproteobacteria and Actinobacteria, which are common bacterial groups in Baltic Sea wintertime surface waters. The pancake ice bacterial communities were similar to the open-water communities, suggesting that the parent water determines the sea-ice bacterial community in the early stages of sea-ice formation. In consolidated young and thick ice, the bacterial communities were significantly different from water bacterial communities as well as from each other, indicating community development in Baltic Sea drift ice along with ice-type changes. The thick ice was dominated by typical sea-ice genera from classes Flavobacteria and Gammaproteobacteria, similar to those in polar sea-ice bacterial communities. Since the thick ice bacterial community was remarkably different from that of the parent seawater, results indicate that thick ice bacterial communities were recruited from the rarer members of the seawater bacterial community. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Ecology of southern ocean pack ice.

    Science.gov (United States)

    Brierley, Andrew S; Thomas, David N

    2002-01-01

    Around Antarctica the annual five-fold growth and decay of sea ice is the most prominent physical process and has a profound impact on marine life there. In winter the pack ice canopy extends to cover almost 20 million square kilometres--some 8% of the southern hemisphere and an area larger than the Antarctic continent itself (13.2 million square kilometres)--and is one of the largest, most dynamic ecosystems on earth. Biological activity is associated with all physical components of the sea-ice system: the sea-ice surface; the internal sea-ice matrix and brine channel system; the underside of sea ice and the waters in the vicinity of sea ice that are modified by the presence of sea ice. Microbial and microalgal communities proliferate on and within sea ice and are grazed by a wide range of proto- and macrozooplankton that inhabit the sea ice in large concentrations. Grazing organisms also exploit biogenic material released from the sea ice at ice break-up or melt. Although rates of primary production in the underlying water column are often low because of shading by sea-ice cover, sea ice itself forms a substratum that provides standing stocks of bacteria, algae and grazers significantly higher than those in ice-free areas. Decay of sea ice in summer releases particulate and dissolved organic matter to the water column, playing a major role in biogeochemical cycling as well as seeding water column phytoplankton blooms. Numerous zooplankton species graze sea-ice algae, benefiting additionally because the overlying sea-ice ceiling provides a refuge from surface predators. Sea ice is an important nursery habitat for Antarctic krill, the pivotal species in the Southern Ocean marine ecosystem. Some deep-water fish migrate to shallow depths beneath sea ice to exploit the elevated concentrations of some zooplankton there. The increased secondary production associated with pack ice and the sea-ice edge is exploited by many higher predators, with seals, seabirds and whales

  10. Structural Instability in Ice VIII under Pressure

    International Nuclear Information System (INIS)

    Besson, J.; Klotz, S.; Hamel, G.; Marshall, W.; Nelmes, R.; Loveday, J.

    1997-01-01

    Below 125K, tetragonal ice VIII remains in a metastable form at ambient pressure. This form has long been considered to be identical to ice VIII, although unexplained discrepancies exist between their vibrational spectra. Neutron diffraction studies reveal an isostructural phase transformation below 2GPa related to a weakening of the bonds between the two D 2 O sublattices of ice VIII. In this new phase, ice VIII ' , the tetragonal distortion is 20% larger than in ice VIII, which accounts for the differences between the vibrational frequencies of the two phases. copyright 1997 The American Physical Society

  11. NASA/FAA Tailplane Icing Program Overview

    Science.gov (United States)

    Ratvasky, Thomas P.; VanZante, Judith Foss; Riley, James T.

    1999-01-01

    The effects of tailplane icing were investigated in a four-year NASA/FAA Tailplane Icing, Program (TIP). This research program was developed to improve the understanding, of iced tailplane aeroperformance and aircraft aerodynamics, and to develop design and training aides to help reduce the number of incidents and accidents caused by tailplane icing. To do this, the TIP was constructed with elements that included icing, wind tunnel testing, dry-air aerodynamic wind tunnel testing, flight tests, and analytical code development. This paper provides an overview of the entire program demonstrating the interconnectivity of the program elements and reports on current accomplishments.

  12. Sea Ice, Climate and Fram Strait

    Science.gov (United States)

    Hunkins, K.

    1984-01-01

    When sea ice is formed the albedo of the ocean surface increases from its open water value of about 0.1 to a value as high as 0.8. This albedo change effects the radiation balance and thus has the potential to alter climate. Sea ice also partially seals off the ocean from the atmosphere, reducing the exchange of gases such as carbon dioxide. This is another possible mechanism by which climate might be affected. The Marginal Ice Zone Experiment (MIZEX 83 to 84) is an international, multidisciplinary study of processes controlling the edge of the ice pack in that area including the interactions between sea, air and ice.

  13. THE SCULPTURE SYMPOSIUM OF UTEBO

    Directory of Open Access Journals (Sweden)

    Társila Gimeno Gimeno

    2008-10-01

    figuration, abstraction, symbolism, conceptualism… To walk by the parks, places and streets of Utebo turns out to be the same experience that appreciated when crossing the rooms of a museum of contemporary art, but with remarkable differences: the works are in open spaces, its perception is never the same because it changes during the day and over the years, and are admired by a more numerous public than in any museum.

  14. There goes the sea ice: following Arctic sea ice parcels and their properties.

    Science.gov (United States)

    Tschudi, M. A.; Tooth, M.; Meier, W.; Stewart, S.

    2017-12-01

    Arctic sea ice distribution has changed considerably over the last couple of decades. Sea ice extent record minimums have been observed in recent years, the distribution of ice age now heavily favors younger ice, and sea ice is likely thinning. This new state of the Arctic sea ice cover has several impacts, including effects on marine life, feedback on the warming of the ocean and atmosphere, and on the future evolution of the ice pack. The shift in the state of the ice cover, from a pack dominated by older ice, to the current state of a pack with mostly young ice, impacts specific properties of the ice pack, and consequently the pack's response to the changing Arctic climate. For example, younger ice typically contains more numerous melt ponds during the melt season, resulting in a lower albedo. First-year ice is typically thinner and more fragile than multi-year ice, making it more susceptible to dynamic and thermodynamic forcing. To investigate the response of the ice pack to climate forcing during summertime melt, we have developed a database that tracks individual Arctic sea ice parcels along with associated properties as these parcels advect during the summer. Our database tracks parcels in the Beaufort Sea, from 1985 - present, along with variables such as ice surface temperature, albedo, ice concentration, and convergence. We are using this database to deduce how these thousands of tracked parcels fare during summer melt, i.e. what fraction of the parcels advect through the Beaufort, and what fraction melts out? The tracked variables describe the thermodynamic and dynamic forcing on these parcels during their journey. This database will also be made available to all interested investigators, after it is published in the near future. The attached image shows the ice surface temperature of all parcels (right) that advected through the Beaufort Sea region (left) in 2014.

  15. Sunlight, Sea Ice, and the Ice Albedo Feedback in a Changing Arctic Sea Ice Cover

    Science.gov (United States)

    2015-09-30

    fraction product and the remotely sensed albedo product in the context of understanding the surface radiation budget. Particular attention is paid to...Stamnes, Chapter 2 The Polar Environment: Sun, Clouds, and Ice, in Ocean Colour Remote Sensing in Polar Seas, p 5-25, in press. Istomina, L, G

  16. Sunlight, Sea Ice, and the Ice Albedo Feedback in a Changing Artic Sea Ice Cover

    Science.gov (United States)

    2015-11-30

    the remotely sensed albedo product in the context of understanding the surface radiation budget. Particular attention is paid to the infrequent...Chapter 2 The Polar Environment: Sun, Clouds, and Ice, in Ocean Colour Remote Sensing in Polar Seas, p 5-25, in press. Istomina, L, G. Heygster, M

  17. Multi-decadal Arctic sea ice roughness.

    Science.gov (United States)

    Tsamados, M.; Stroeve, J.; Kharbouche, S.; Muller, J. P., , Prof; Nolin, A. W.; Petty, A.; Haas, C.; Girard-Ardhuin, F.; Landy, J.

    2017-12-01

    The transformation of Arctic sea ice from mainly perennial, multi-year ice to a seasonal, first-year ice is believed to have been accompanied by a reduction of the roughness of the ice cover surface. This smoothening effect has been shown to (i) modify the momentum and heat transfer between the atmosphere and ocean, (ii) to alter the ice thickness distribution which in turn controls the snow and melt pond repartition over the ice cover, and (iii) to bias airborne and satellite remote sensing measurements that depend on the scattering and reflective characteristics over the sea ice surface topography. We will review existing and novel remote sensing methodologies proposed to estimate sea ice roughness, ranging from airborne LIDAR measurement (ie Operation IceBridge), to backscatter coefficients from scatterometers (ASCAT, QUICKSCAT), to multi angle maging spectroradiometer (MISR), and to laser (Icesat) and radar altimeters (Envisat, Cryosat, Altika, Sentinel-3). We will show that by comparing and cross-calibrating these different products we can offer a consistent multi-mission, multi-decadal view of the declining sea ice roughness. Implications for sea ice physics, climate and remote sensing will also be discussed.

  18. Ice-Cliff Failure via Retrogressive Slumping

    Science.gov (United States)

    Parizek, B. R.; Christianson, K.; Alley, R. B.; Voytenko, D.; Vankova, I.; Dixon, T. H.; Holland, D.

    2016-12-01

    The magnitude and rate of future sea-level rise from warming-induced ice-sheet shrinkage remain notably uncertain. Removal of most of an ice sheet by surface melting alone requires centuries to millennia. Oceanic warming may accelerate loss by removing buttressing ice shelves and thereby speeding flow of non-floating ice into the ocean, but, until recently, modeled timescales for major dynamic ice-sheet shrinkage were centuries or longer. Beyond certain thresholds, however, observations show that warming removes floating ice shelves, leaving grounded ice cliffs from which icebergs break off directly. Cliffs higher than some limit experience rapid structural failure. Recent parameterization of this process in a comprehensive ice-flow model produced much faster sea-level rise from future rapid warming than in previous modeling studies, through formation and retreat of tall ice cliffs. Fully physical representations of this process are not yet available, however. Here, we use modeling guided by terrestrial radar data from Helheim Glacier, Greenland to show that cliffs will fail by slumping and trigger rapid retreat at a threshold height that, in crevassed ice with surface melting, may be only slightly above the 100-m maximum observed today, but may be roughly twice that (180-275 m) in mechanically-competent ice under well-drained or low-melt conditions.

  19. Evidence for radionuclide transport by sea ice

    International Nuclear Information System (INIS)

    Meese, D.A.; Tucker, W.B.; Gow, A.J.; Reimnitz, E.; Bischof, J.; Darby, D.

    1997-01-01

    Ice and ice-borne sediments were collected across the Arctic Basin during the Arctic Ocean Section, 1994 (AOS-94), a recent US/Canada trans-Arctic expedition. Sediments were analysed for 137 Cs, clay mineralogy and carbon. Concentrations of 137 Cs ranged from 5 to 73 Bq kg -1 in the ice-borne sediments. Concentrations of ice samples without sediment were all less than 1 Bq m -3 . The sediment sample with the highest 137 Cs concentration (73 Bq kg -1 ) was collected in the Beaufort Sea. This concentration was significantly higher than in bottom sediments collected in the same area, indicating an ice transport mechanism from an area with correspondingly higher concentrations. Recent results from the application of ice transport models and sediment analyses indicate that it is very likely that sediments are transported by ice, from the Siberian shelf areas to the Beaufort Sea

  20. Ice Accretion on Wind Turbine Blades

    DEFF Research Database (Denmark)

    Hudecz, Adriána; Koss, Holger; Hansen, Martin Otto Laver

    2013-01-01

    In this paper, both experimental and numerical simulations of the effects of ice accretion on a NACA 64-618 airfoil section with 7° angle of attack are presented. The wind tunnel tests were conducted in a closed-circuit climatic wind tunnel at Force Technology in Denmark. The changes of aerodynamic...... forces were monitored as ice was building up on the airfoil for glaze, rime and mixed ice. In the first part of the numerical analysis, the resulted ice profiles of the wind tunnel tests were compared to profiles estimated by using the 2D ice accretion code TURBICE. In the second part, Ansys Fluent...... of the rime iced ice profile follows the streamlines quite well, disturbing the flow the least. The TURBICE analysis agrees fairly with the profiles produced during the wind tunnel testing....

  1. Role of stacking disorder in ice nucleation.

    Science.gov (United States)

    Lupi, Laura; Hudait, Arpa; Peters, Baron; Grünwald, Michael; Gotchy Mullen, Ryan; Nguyen, Andrew H; Molinero, Valeria

    2017-11-08

    The freezing of water affects the processes that determine Earth's climate. Therefore, accurate weather and climate forecasts hinge on good predictions of ice nucleation rates. Such rate predictions are based on extrapolations using classical nucleation theory, which assumes that the structure of nanometre-sized ice crystallites corresponds to that of hexagonal ice, the thermodynamically stable form of bulk ice. However, simulations with various water models find that ice nucleated and grown under atmospheric temperatures is at all sizes stacking-disordered, consisting of random sequences of cubic and hexagonal ice layers. This implies that stacking-disordered ice crystallites either are more stable than hexagonal ice crystallites or form because of non-equilibrium dynamical effects. Both scenarios challenge central tenets of classical nucleation theory. Here we use rare-event sampling and free energy calculations with the mW water model to show that the entropy of mixing cubic and hexagonal layers makes stacking-disordered ice the stable phase for crystallites up to a size of at least 100,000 molecules. We find that stacking-disordered critical crystallites at 230 kelvin are about 14 kilojoules per mole of crystallite more stable than hexagonal crystallites, making their ice nucleation rates more than three orders of magnitude higher than predicted by classical nucleation theory. This effect on nucleation rates is temperature dependent, being the most pronounced at the warmest conditions, and should affect the modelling of cloud formation and ice particle numbers, which are very sensitive to the temperature dependence of ice nucleation rates. We conclude that classical nucleation theory needs to be corrected to include the dependence of the crystallization driving force on the size of the ice crystallite when interpreting and extrapolating ice nucleation rates from experimental laboratory conditions to the temperatures that occur in clouds.

  2. Observed ices in the Solar System

    Science.gov (United States)

    Clark, Roger N.; Grundy, Will; Carlson, Robert R.; Noll, Keith; Gudipati, Murthy; Castillo-Rogez, Julie C.

    2013-01-01

    Ices have been detected and mapped on the Earth and all planets and/or their satellites further from the sun. Water ice is the most common frozen volatile observed and is also unambiguously detected or inferred in every planet and/or their moon(s) except Venus. Carbon dioxide is also extensively found in all systems beyond the Earth except Pluto although it sometimes appears to be trapped rather than as an ice on some objects. The largest deposits of carbon dioxide ice is on Mars. Sulfur dioxide ice is found in the Jupiter system. Nitrogen and methane ices are common beyond the Uranian system. Saturn’s moon Titan probably has the most complex active chemistry involving ices, with benzene (C6H6) and many tentative or inferred compounds including ices of Cyanoacetylene (HC3N), Toluene (C7H8), Cyanogen (C2N2), Acetonitrile (CH3CN), H2O, CO2, and NH3. Confirming compounds on Titan is hampered by its thick smoggy atmosphere. Ammonia was predicted on many icy moons but is notably absent among the definitively detected ices with the possible exception of Enceladus. Comets, storehouses of many compounds that could exist as ices in their nuclei, have only had small amounts of water ice definitively detected on their surfaces. Only one asteroid has had a direct detection of surface water ice, although its presence can be inferred in others. This chapter reviews some of the properties of ices that lead to their detection, and surveys the ices that have been observed on solid surfaces throughout the Solar System.

  3. Multiyear ice transport and small scale sea ice deformation near the Alaska coast measured by air-deployable Ice Trackers

    Science.gov (United States)

    Mahoney, A. R.; Kasper, J.; Winsor, P.

    2015-12-01

    Highly complex patterns of ice motion and deformation were captured by fifteen satellite-telemetered GPS buoys (known as Ice Trackers) deployed near Barrow, Alaska, in spring 2015. Two pentagonal clusters of buoys were deployed on pack ice by helicopter in the Beaufort Sea between 20 and 80 km offshore. During deployment, ice motion in the study region was effectively zero, but two days later the buoys captured a rapid transport event in which multiyear ice from the Beaufort Sea was flushed into the Chukchi Sea. During this event, westward ice motion began in the Chukchi Sea and propagated eastward. This created new openings in the ice and led to rapid elongation of the clusters as the westernmost buoys accelerated away from their neighbors to the east. The buoys tracked ice velocities of over 1.5 ms-1, with fastest motion occurring closest to the coast indicating strong current shear. Three days later, ice motion reversed and the two clusters became intermingled, rendering divergence calculations based on the area enclosed by clusters invalid. The data show no detectable difference in velocity between first year and multiyear ice floes, but Lagrangian timeseries of SAR imagery centered on each buoy show that first year ice underwent significant small-scale deformation during the event. The five remaining buoys were deployed by local residents on prominent ridges embedded in the landfast ice within 16 km of Barrow in order to track the fate of such features after they detached from the coast. Break-up of the landfast ice took place over a period of several days and, although the buoys each initially followed a similar eastward trajectory around Point Barrow into the Beaufort Sea, they rapidly dispersed over an area more than 50 km across. With rapid environmental and socio-economic change in the Arctic, understanding the complexity of nearshore ice motion is increasingly important for predict future changes in the ice and the tracking ice-related hazards

  4. EBSD in Antarctic and Greenland Ice

    Science.gov (United States)

    Weikusat, Ilka; Kuiper, Ernst-Jan; Pennock, Gill; Sepp, Kipfstuhl; Drury, Martyn

    2017-04-01

    Ice, particularly the extensive amounts found in the polar ice sheets, impacts directly on the global climate by changing the albedo and indirectly by supplying an enormous water reservoir that affects sea level change. The discharge of material into the oceans is partly controlled by the melt excess over snow accumulation, partly by the dynamic flow of ice. In addition to sliding over bedrock, an ice body deforms gravitationally under its own weight. In order to improve our description of this flow, ice microstructure studies are needed that elucidate the dominant deformation and recrystallization mechanisms involved. Deformation of hexagonal ice is highly anisotropic: ice is easily sheared in the basal plane and is about two orders of magnitude harder parallel to the c-axis. As dislocation creep is the dominant deformation mechanism in polar ice this strong anisotropy needs to be understood in terms of dislocation activity. The high anisotropy of the ice crystal is usually ascribed to a particular behaviour of dislocations in ice, namely the extension of dislocations into partials on the basal plane. Analysis of EBSD data can help our understanding of dislocation activity by characterizing subgrain boundary types thus providing a tool for comprehensive dislocation characterization in polar ice. Cryo-EBSD microstructure in combination with light microscopy measurements from ice core material from Antarctica (EPICA-DML deep ice core) and Greenland (NEEM deep ice core) are presented and interpreted regarding substructure identification and characterization. We examined one depth for each ice core (EDML: 656 m, NEEM: 719 m) to obtain the first comparison of slip system activity from the two ice sheets. The subgrain boundary to grain boundary threshold misorientation was taken to be 3-5° (Weikusat et al. 2011). EBSD analyses suggest that a large portion of edge dislocations with slip systems basal gliding on the basal plane were indeed involved in forming subgrain

  5. Life in Ice: Implications to Astrobiology

    Science.gov (United States)

    Hoover, Richard B.

    2009-01-01

    During the 2008 Tawani International Expedition Schirmacher Oasis/Lake Untersee Antarctica Expedition, living and instantly motile bacteria were found in freshly thawed meltwater from ice of the Schirmacher Oasis Lakes, the Anuchin Glacier ice and samples of the that perennial ice sheet above Lake Untersee. This phenomenon of living bacteria encased in ice had previously been observed in the 32,000 year old ice of the Fox Tunnel. The bacteria found in this ice included the strain FTR1T which was isolated and published as valid new species (Carnobacterium pleistocenium) the first validly published living Pleistocene organism still alive today. Living bacteria were also extracted from ancient ice cores from Vostok, Antarctica. The discovery that many strains of bacteria are able to survive and remain alive while frozen in ice sheets for long periods of time may have direct relevance to Astrobiology. The abundance of viable bacteria in the ice sheets of Antarctica suggests that the presence of live bacteria in ice is common, rather than an isolated phenomenon. This paper will discuss the results of recent studies at NSSTC of bacteria cryopreserved in ice. This paper advances the hypothesis that cryopreserved cells, and perhaps even viable bacterial cells, may exist today--frozen in the water-ice of lunar craters, the Polar Caps or craters of Mars; or in the permafrost of Mars; ice and rocks of comets or water bearing asteroids; or in the frozen crusts of the icy moons of Jupiter and Saturn. The existence of bacterial life in ice suggests that it may not be necessary to drill through a thick ice crust to reach liquid water seas deep beneath the icy crusts of Europa, Ganymede and Enceladus. The presence of viable bacteria in the ice of the Earth s Polar Caps suggests that the possibility that cryo-panspermia (i.e., the trans-planetary transfer of microbial life by impact ejection/spallation of bacteria-rich polar ice masses) deserves serious consideration and study as a

  6. The effect of ice-cream-scoop water on the hygiene of ice cream.

    Science.gov (United States)

    Wilson, I. G.; Heaney, J. C.; Weatherup, S. T.

    1997-01-01

    A survey of unopened ice cream, ice cream in use, and ice-cream-scoop water (n = 91) was conducted to determine the effect of scoop water hygiene on the microbiological quality of ice cream. An aerobic plate count around 10(6) c.f.u. ml-1 was the modal value for scoop waters. Unopened ice creams generally had counts around 10(3)-10(4) c.f.u. ml-1 and this increased by one order of magnitude when in use. Many scoop waters had low coliform counts, but almost half contained > 100 c.f.u. ml-1. E. coli was isolated in 18% of ice creams in use, and in 10% of unopened ice creams. S. aureus was not detected in any sample. Statistical analysis showed strong associations between indicator organisms and increased counts in ice cream in use. EC guidelines for indicator organisms in ice cream were exceeded by up to 56% of samples. PMID:9287941

  7. The future of ice sheets and sea ice: between reversible retreat and unstoppable loss.

    Science.gov (United States)

    Notz, Dirk

    2009-12-08

    We discuss the existence of cryospheric "tipping points" in the Earth's climate system. Such critical thresholds have been suggested to exist for the disappearance of Arctic sea ice and the retreat of ice sheets: Once these ice masses have shrunk below an anticipated critical extent, the ice-albedo feedback might lead to the irreversible and unstoppable loss of the remaining ice. We here give an overview of our current understanding of such threshold behavior. By using conceptual arguments, we review the recent findings that such a tipping point probably does not exist for the loss of Arctic summer sea ice. Hence, in a cooler climate, sea ice could recover rapidly from the loss it has experienced in recent years. In addition, we discuss why this recent rapid retreat of Arctic summer sea ice might largely be a consequence of a slow shift in ice-thickness distribution, which will lead to strongly increased year-to-year variability of the Arctic summer sea-ice extent. This variability will render seasonal forecasts of the Arctic summer sea-ice extent increasingly difficult. We also discuss why, in contrast to Arctic summer sea ice, a tipping point is more likely to exist for the loss of the Greenland ice sheet and the West Antarctic ice sheet.

  8. Sea ice and pollution-modulated changes in Greenland ice core methanesulfonate and bromine

    Science.gov (United States)

    Maselli, Olivia J.; Chellman, Nathan J.; Grieman, Mackenzie; Layman, Lawrence; McConnell, Joseph R.; Pasteris, Daniel; Rhodes, Rachael H.; Saltzman, Eric; Sigl, Michael

    2017-01-01

    Reconstruction of past changes in Arctic sea ice extent may be critical for understanding its future evolution. Methanesulfonate (MSA) and bromine concentrations preserved in ice cores have both been proposed as indicators of past sea ice conditions. In this study, two ice cores from central and north-eastern Greenland were analysed at sub-annual resolution for MSA (CH3SO3H) and bromine, covering the time period 1750-2010. We examine correlations between ice core MSA and the HadISST1 ICE sea ice dataset and consult back trajectories to infer the likely source regions. A strong correlation between the low-frequency MSA and bromine records during pre-industrial times indicates that both chemical species are likely linked to processes occurring on or near sea ice in the same source regions. The positive correlation between ice core MSA and bromine persists until the mid-20th century, when the acidity of Greenland ice begins to increase markedly due to increased fossil fuel emissions. After that time, MSA levels decrease as a result of declining sea ice extent but bromine levels increase. We consider several possible explanations and ultimately suggest that increased acidity, specifically nitric acid, of snow on sea ice stimulates the release of reactive Br from sea ice, resulting in increased transport and deposition on the Greenland ice sheet.

  9. Evidence for middle Eocene Arctic sea ice from diatoms and ice-rafted debris.

    Science.gov (United States)

    Stickley, Catherine E; St John, Kristen; Koç, Nalân; Jordan, Richard W; Passchier, Sandra; Pearce, Richard B; Kearns, Lance E

    2009-07-16

    Oceanic sediments from long cores drilled on the Lomonosov ridge, in the central Arctic, contain ice-rafted debris (IRD) back to the middle Eocene epoch, prompting recent suggestions that ice appeared in the Arctic about 46 million years (Myr) ago. However, because IRD can be transported by icebergs (derived from land-based ice) and also by sea ice, IRD records are restricted to providing a history of general ice-rafting only. It is critical to differentiate sea ice from glacial (land-based) ice as climate feedback mechanisms vary and global impacts differ between these systems: sea ice directly affects ocean-atmosphere exchanges, whereas land-based ice affects sea level and consequently ocean acidity. An earlier report assumed that sea ice was prevalent in the middle Eocene Arctic on the basis of IRD, and although somewhat preliminary supportive evidence exists, these data are neither comprehensive nor quantified. Here we show the presence of middle Eocene Arctic sea ice from an extraordinary abundance of a group of sea-ice-dependent fossil diatoms (Synedropsis spp.). Analysis of quartz grain textural characteristics further supports sea ice as the dominant transporter of IRD at this time. Together with new information on cosmopolitan diatoms and existing IRD records, our data strongly suggest a two-phase establishment of sea ice: initial episodic formation in marginal shelf areas approximately 47.5 Myr ago, followed approximately 0.5 Myr later by the onset of seasonally paced sea-ice formation in offshore areas of the central Arctic. Our data establish a 2-Myr record of sea ice, documenting the transition from a warm, ice-free environment to one dominated by winter sea ice at the start of the middle Eocene climatic cooling phase.

  10. Pressure melting and ice skating

    Science.gov (United States)

    Colbeck, S. C.

    1995-10-01

    Pressure melting cannot be responsible for the low friction of ice. The pressure needed to reach the melting temperature is above the compressive failure stress and, if it did occur, high squeeze losses would result in very thin films. Pure liquid water cannot coexist with ice much below -20 °C at any pressure and friction does not increase suddenly in that range. If frictional heating and pressure melting contribute equally, the length of the wetted contact could not exceed 15 μm at a speed of 5 m/s, which seems much too short. If pressure melting is the dominant process, the water films are less than 0.08 μm thick because of the high pressures.

  11. Controls on Arctic sea ice from first-year and multi-year ice survival rates

    Science.gov (United States)

    Armour, K.; Bitz, C. M.; Hunke, E. C.; Thompson, L.

    2009-12-01

    The recent decrease in Arctic sea ice cover has transpired with a significant loss of multi-year (MY) ice. The transition to an Arctic that is populated by thinner first-year (FY) sea ice has important implications for future trends in area and volume. We develop a reduced model for Arctic sea ice with which we investigate how the survivability of FY and MY ice control various aspects of the sea-ice system. We demonstrate that Arctic sea-ice area and volume behave approximately as first-order autoregressive processes, which allows for a simple interpretation of September sea-ice in which its mean state, variability, and sensitivity to climate forcing can be described naturally in terms of the average survival rates of FY and MY ice. This model, used in concert with a sea-ice simulation that traces FY and MY ice areas to estimate the survival rates, reveals that small trends in the ice survival rates explain the decline in total Arctic ice area, and the relatively larger loss of MY ice area, over the period 1979-2006. Additionally, our model allows for a calculation of the persistence time scales of September area and volume anomalies. A relatively short memory time scale for ice area (~ 1 year) implies that Arctic ice area is nearly in equilibrium with long-term climate forcing at all times, and therefore observed trends in area are a clear indication of a changing climate. A longer memory time scale for ice volume (~ 5 years) suggests that volume can be out of equilibrium with climate forcing for long periods of time, and therefore trends in ice volume are difficult to distinguish from its natural variability. With our reduced model, we demonstrate the connection between memory time scale and sensitivity to climate forcing, and discuss the implications that a changing memory time scale has on the trajectory of ice area and volume in a warming climate. Our findings indicate that it is unlikely that a “tipping point” in September ice area and volume will be

  12. Observation and modeling of snow melt and superimposed ice formation on sea ice

    OpenAIRE

    Nicolaus, Marcel; Haas, Christian

    2004-01-01

    Sea ice plays a key role within the global climate system. It covers some 7% of earths surface and processes a strong seasonal cycle. Snow on sea ice even amplifies the importance of sea ice in the coupled atmosphere-ice-ocean system, because it dominates surface properties and energy balance (incl. albedo).Several quantitative observations of summer sea ice and its snow cover show the formation of superimposed ice and a gap layer underneath, which was found to be associated to high standing ...

  13. “Corte Transversal”: una mega escultura entre el río Mapocho y la autopista Costanera Norte en Santiago de Chile/ “Corte Transversal”: a mega sculpture between the Mapocho River and the Costanera Norte toll road in Santiago de Chile

    Directory of Open Access Journals (Sweden)

    Revista de Urbanismo, Departamento de Urbanismo de la Facultad de Arquitectura y Urbanismo de la Universidad de Chile. (Reportaje de M.I.PavezR.- M.P.Henríquez.O

    2008-12-01

    Full Text Available “Corte Transversal”: una mega escultura entre el río Mapocho y la autopista Costanera Norte en Santiago de Chile/“Corte Transversal”: a mega sculpture between the Mapocho River and the Costanera Norte toll road in Santiago de Chile

  14. The 3 micron ice band

    International Nuclear Information System (INIS)

    Greenberg, J.M.; Bult, C.E.P.M. van de

    1984-01-01

    Ever since it was proposed that H 2 O could be a dominant constituent of interstellar grains, its detection, or lack thereof, has played a large role in theories of grains and their evolution. It now appears possible to provide a basic theoretical structure for the evolution of grains in molecular clouds based on current observational evidence and laboratory experiments on the ice band. Both band strengths and shapes can be reasonably predicted by grain models. (U.K.)

  15. Ice Segregation and Frost Heaving.

    Science.gov (United States)

    1984-01-01

    to a buried chilled gas pipeline by continual frost ’. ’- heave during the service life or to a buried liquefied gas tank is a more _ recent concern...M). Lule en: Uiversity of Lulea. Pehner, E., 1982. Aspects of ice lens fornmation. P ing of the Third International Syvosium on Ground Freezi, Hanover...Soils. Lalea, Sweden: Uiversity ofLulea. . Berg, R. L., G. Guymon and J. Ingersoll, 1979. Conference on soil-water . problems in cold regions. Cold

  16. Solar ice; Sonne und Eis

    Energy Technology Data Exchange (ETDEWEB)

    Rolland, Simon

    2012-07-01

    Fishing and fish marketing are the major sources of income at Santo Antao, the biggest of the Cape Verde Islands off Africa's west coast. In the coastal village of Monte Trigo, ice for keeping the fish fresh is now produced by a photovoltaic plant. As the Alliance for Rural Electrification recently reported, the community now gets its power from a 27.3 kW local power grid.

  17. Ice storm 1998 : lessons learned

    Energy Technology Data Exchange (ETDEWEB)

    McCready, J. [Eastern Ontario Model Forest, Kemptville, ON (Canada)

    2006-07-01

    This paper presented details of a partnership formed in response to the ice storm of 1998, which caused extensive damage to trees in woodlots and urban settings in eastern Ontario and western Quebec. The aim of the Ice Storm Forest Recovery Group was to assist in the recovery of eastern forests, collect information on the extent of the damage to trees as well as contribute to the development of assistance programs for woodlot owners and municipalities. In response to the group's request, an initial aerial survey was conducted by the Ontario Ministry of Natural Resources to map the extent of the damage in eastern Ontario, which was followed by a more scientific survey with the Canadian Forest Service through the development of a flying grid pattern to observe the status of trees, followed by extensive ground checks. Damage was variable, depending on tree species, stand age and composition, management practices, wind direction, topography and ice deposition patterns. A summary of the severity of damage indicated that conifers suffered less than hardwoods. Consultants were hired to prepare news releases and extension notes to the public in order to provide information for the caring of trees. Various educational workshops were held which attracted large numbers of landowners and homeowners. A literature review was undertaken to produce a summary of current published knowledge covering the effects of storms and ice damage to trees and forests. Science efforts were published in a series of papers, and financial assistance programs were then organized by governmental agencies. It was concluded that cooperation between all agencies, groups and levels of government is needed in order to coordinate effective emergency strategies. 7 refs., 1 tab., 1 fig.

  18. Simulating Extraterrestrial Ices in the Laboratory

    Science.gov (United States)

    Berisford, D. F.; Carey, E. M.; Hand, K. P.; Choukroun, M.

    2017-12-01

    Several ongoing experiments at JPL attempt to simulate the ice environment for various regimes associated with icy moons. The Europa Penitent Ice Experiment (EPIX) simulates the surface environment of an icy moon, to investigate the physics of ice surface morphology growth. This experiment features half-meter-scale cryogenic ice samples, cryogenic radiative sink environment, vacuum conditions, and diurnal cycling solar simulation. The experiment also includes several smaller fixed-geometry vacuum chambers for ice simulation at Earth-like and intermediate temperature and vacuum conditions for development of surface morphology growth scaling relations. Additionally, an ice cutting facility built on a similar platform provides qualitative data on the mechanical behavior of cryogenic ice with impurities under vacuum, and allows testing of ice cutting/sampling tools relevant for landing spacecraft. A larger cutting facility is under construction at JPL, which will provide more quantitative data and allow full-scale sampling tool tests. Another facility, the JPL Ice Physics Laboratory, features icy analog simulant preparation abilities that range icy solar system objects such as Mars, Ceres and the icy satellites of Saturn and Jupiter. In addition, the Ice Physics Lab has unique facilities for Icy Analog Tidal Simulation and Rheological Studies of Cryogenic Icy Slurries, as well as equipment to perform thermal and mechanical properties testing on icy analog materials and their response to sinusoidal tidal stresses.

  19. Thick or Thin Ice Shell on Europa?

    Science.gov (United States)

    2007-01-01

    Scientists are all but certain that Europa has an ocean underneath its icy surface, but they do not know how thick this ice might be. This artist concept illustrates two possible cut-away views through Europa's ice shell. In both, heat escapes, possibly volcanically, from Europa's rocky mantle and is carried upward by buoyant oceanic currents. If the heat from below is intense and the ice shell is thin enough (left), the ice shell can directly melt, causing what are called 'chaos' on Europa, regions of what appear to be broken, rotated and tilted ice blocks. On the other hand, if the ice shell is sufficiently thick (right), the less intense interior heat will be transferred to the warmer ice at the bottom of the shell, and additional heat is generated by tidal squeezing of the warmer ice. This warmer ice will slowly rise, flowing as glaciers do on Earth, and the slow but steady motion may also disrupt the extremely cold, brittle ice at the surface. Europa is no larger than Earth's moon, and its internal heating stems from its eccentric orbit about Jupiter, seen in the distance. As tides raised by Jupiter in Europa's ocean rise and fall, they may cause cracking, additional heating and even venting of water vapor into the airless sky above Europa's icy surface. (Artwork by Michael Carroll.)

  20. Coordinated Mapping of Sea Ice Deformation Features with Autonomous Vehicles

    Science.gov (United States)

    Maksym, T.; Williams, G. D.; Singh, H.; Weissling, B.; Anderson, J.; Maki, T.; Ackley, S. F.

    2016-12-01

    Decreases in summer sea ice extent in the Beaufort and Chukchi Seas has lead to a transition from a largely perennial ice cover, to a seasonal ice cover. This drives shifts in sea ice production, dynamics, ice types, and thickness distribution. To examine how the processes driving ice advance might also impact the morphology of the ice cover, a coordinated ice mapping effort was undertaken during a field campaign in the Beaufort Sea in October, 2015. Here, we present observations of sea ice draft topography from six missions of an Autonomous Underwater Vehicle run under different ice types and deformation features observed during autumn freeze-up. Ice surface features were also mapped during coordinated drone photogrammetric missions over each site. We present preliminary results of a comparison between sea ice surface topography and ice underside morphology for a range of sample ice types, including hummocked multiyear ice, rubble fields, young ice ridges and rafts, and consolidated pancake ice. These data are compared to prior observations of ice morphological features from deformed Antarctic sea ice. Such data will be useful for improving parameterizations of sea ice redistribution during deformation, and for better constraining estimates of airborne or satellite sea ice thickness.

  1. How ice shelf morphology controls basal melting

    Science.gov (United States)

    Little, Christopher M.; Gnanadesikan, Anand; Oppenheimer, Michael

    2009-12-01

    The response of ice shelf basal melting to climate is a function of ocean temperature, circulation, and mixing in the open ocean and the coupling of this external forcing to the sub-ice shelf circulation. Because slope strongly influences the properties of buoyancy-driven flow near the ice shelf base, ice shelf morphology plays a critical role in linking external, subsurface heat sources to the ice. In this paper, the slope-driven dynamic control of local and area-integrated melting rates is examined under a wide range of ocean temperatures and ice shelf shapes, with an emphasis on smaller, steeper ice shelves. A 3-D numerical ocean model is used to simulate the circulation underneath five idealized ice shelves, forced with subsurface ocean temperatures ranging from -2.0°C to 1.5°C. In the sub-ice shelf mixed layer, three spatially distinct dynamic regimes are present. Entrainment of heat occurs predominately under deeper sections of the ice shelf; local and area-integrated melting rates are most sensitive to changes in slope in this "initiation" region. Some entrained heat is advected upslope and used to melt ice in the "maintenance" region; however, flow convergence in the "outflow" region limits heat loss in flatter portions of the ice shelf. Heat flux to the ice exhibits (1) a spatially nonuniform, superlinear dependence on slope and (2) a shape- and temperature-dependent, internally controlled efficiency. Because the efficiency of heat flux through the mixed layer decreases with increasing ocean temperature, numerical simulations diverge from a simple quadratic scaling law.

  2. Sintering and microstructure of ice: a review

    International Nuclear Information System (INIS)

    Blackford, Jane R

    2007-01-01

    Sintering of ice is driven by the thermodynamic requirement to decrease surface energy. The structural morphology of ice in nature has many forms-from snowflakes to glaciers. These forms and their evolution depend critically on the balance between the thermodynamic and kinetic factors involved. Ice is a crystalline material so scientific understanding and approaches from more conventional materials can be applied to ice. The early models of solid state ice sintering are based on power law models originally developed in metallurgy. For pressure sintering of ice, these are based on work on hot isostatic pressing of metals and ceramics. Recent advances in recognizing the grain boundary groove geometry between sintering ice particles require models that use new approaches in materials science. The newer models of sintering in materials science are beginning to incorporate more realistic processing conditions and microstructural complexity, and so there is much to be gained from applying these to ice in the future. The vapour pressure of ice is high, which causes it to sublime readily. The main mechanism for isothermal sintering of ice particles is by vapour diffusion; however other transport mechanisms certainly contribute. Plastic deformation with power law creep combined with recrystallization become important mechanisms in sintering with external pressure. Modern experimental techniques, low temperature scanning electron microscopy and x-ray tomography, are providing new insights into the evolution of microstructures in ice. Sintering in the presence of a small volume fraction of the liquid phase causes much higher bond growth rates. This may be important in natural snow which contains impurities that form a liquid phase. Knowledge of ice microstructure and sintering is beneficial in understanding mechanical behaviour in ice friction and the stability of snow slopes prone to avalanches. (topical review)

  3. Theory of ice-skating

    Science.gov (United States)

    Le Berre, Martine; Pomeau, Yves

    2015-10-01

    Almost frictionless skating on ice relies on a thin layer of melted water insulating mechanically the blade of the skate from ice. Using the basic equations of fluid mechanics and Stefan law, we derive a set of two coupled equations for the thickness of the film and the length of contact, a length scale which cannot be taken as its value at rest. The analytical study of these equations allows to define a small a-dimensional parameter depending on the longitudinal coordinate which can be neglected everywhere except close to the contact points at the front and the end of the blade, where a boundary layer solution is given. This solution provides without any calculation the order of magnitude of the film thickness, and its dependence with respect to external parameters like the velocity and mass of the skater and the radius of profile and bite angle of the blade, in good agreement with the numerical study. Moreover this solution also shows that a lubricating water layer of macroscopic thickness always exists for standard values of ice skating data, contrary to what happens in the case of cavitation of droplets due to thermal heating (Leidenfrost effect).

  4. ICE-DIP kicks off

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    Last month, Marie Curie Actions* added a new member to its ranks: ICE-DIP (the Intel-CERN European Doctorate Industrial Program). The programme held its kick-off meeting on 18-19 February in Leixlip near Dublin, Ireland, at Intel’s premises.   Building on CERN’s long-standing relationship with Intel in the CERN openlab project, ICE-DIP brings together CERN and industrial partners, Intel and Xena Networks, to train five Early Stage ICT Researchers. These researchers will be funded by the European Commission and granted a CERN Fellow contract while enrolled in the doctoral programmes at partner universities Dublin City University and National University of Ireland Maynooth. The researchers will go on extended secondments to Intel Labs Europe locations across Europe during their three-year training programme. The primary focus of the ICE-DIP researchers will be the development of techniques for acquiring and processing data that are relevant for the trigger a...

  5. On the Predictability of Sea Ice

    Science.gov (United States)

    Blanchard-Wrigglesworth, Edward

    We investigate the persistence and predictability of sea ice in numerical models and observations. We first use the 3rd generation Community Climate System Model (CCSM3) General Circulation Model (GCM) to investigate the inherent persistence of sea-ice area and thickness. We find that sea-ice area anomalies have a seasonal decay timescale, exhibiting an initial decorrelation similar to a first order auto-regressive (AR1, or red noise) process. Beyond this initial loss of memory, there is a re-emergence of memory at certain times of the year. There are two distinct modes of re-emergence in the model, one driven by the seasonal coupling of area and thickness anomalies in the summer, the other by the persistence of upper ocean temperature anomalies that originate from ice anomalies in the melt season and then influence ice anomalies in the growth season. Comparison with satellite observations where available indicate these processes appear in nature. We then use the 4th generation CCSM (CCSM4) to investigate the partition of Arctic sea-ice predictability into its initial-value and boundary forced components under present day forcing conditions. We find that initial-value predictability lasts for 1-2 years for sea-ice area, and 3-4 years for sea-ice volume. Forced predictability arises after just 4-5 years for both area and volume. Initial-value predictability of sea-ice area during the summer hinges on the coupling between thickness and area anomalies during that season. We find that the loss of initial-value predictability with time is not uniform --- there is a rapid loss of predictability of sea-ice volume during the late spring early summer associated with snow melt and albedo feedbacks. At the same time, loss of predictability is not uniform across different regions. Given the usefulness of ice thickness as a predictor of summer sea-ice area, we obtain a hindcast of September sea-ice area initializing the GCM on May 1with an estimate of observed sea-ice thickness

  6. Understanding Ice Shelf Basal Melting Using Convergent ICEPOD Data Sets: ROSETTA-Ice Study of Ross Ice Shelf

    Science.gov (United States)

    Bell, R. E.; Frearson, N.; Tinto, K. J.; Das, I.; Fricker, H. A.; Siddoway, C. S.; Padman, L.

    2017-12-01

    The future stability of the ice shelves surrounding Antarctica will be susceptible to increases in both surface and basal melt as the atmosphere and ocean warm. The ROSETTA-Ice program is targeted at using the ICEPOD airborne technology to produce new constraints on Ross Ice Shelf, the underlying ocean, bathymetry, and geologic setting, using radar sounding, gravimetry and laser altimetry. This convergent approach to studying the ice-shelf and basal processes enables us to develop an understanding of the fundamental controls on ice-shelf evolution. This work leverages the stratigraphy of the ice shelf, which is detected as individual reflectors by the shallow-ice radar and is often associated with surface scour, form close to the grounding line or pinning points on the ice shelf. Surface accumulation on the ice shelf buries these reflectors as the ice flows towards the calving front. This distinctive stratigraphy can be traced across the ice shelf for the major East Antarctic outlet glaciers and West Antarctic ice streams. Changes in the ice thickness below these reflectors are a result of strain and basal melting and freezing. Correcting the estimated thickness changes for strain using RIGGS strain measurements, we can develop decadal-resolution flowline distributions of basal melt. Close to East Antarctica elevated melt-rates (>1 m/yr) are found 60-100 km from the calving front. On the West Antarctic side high melt rates primarily develop within 10 km of the calving front. The East Antarctic side of Ross Ice Shelf is dominated by melt driven by saline water masses that develop in Ross Sea polynyas, while the melting on the West Antarctic side next to Hayes Bank is associated with modified Continental Deep Water transported along the continental shelf. The two sides of Ross Ice Shelf experience differing basal melt in part due to the duality in the underlying geologic structure: the East Antarctic side consists of relatively dense crust, with low amplitude

  7. Duality of Ross Ice Shelf systems: crustal boundary, ice sheet processes and ocean circulation from ROSETTA-Ice surveys

    Science.gov (United States)

    Tinto, K. J.; Siddoway, C. S.; Padman, L.; Fricker, H. A.; Das, I.; Porter, D. F.; Springer, S. R.; Siegfried, M. R.; Caratori Tontini, F.; Bell, R. E.

    2017-12-01

    Bathymetry beneath Antarctic ice shelves controls sub-ice-shelf ocean circulation and has a major influence on the stability and dynamics of the ice sheets. Beneath the Ross Ice Shelf, the sea-floor bathymetry is a product of both tectonics and glacial processes, and is influenced by the processes it controls. New aerogeophysical surveys have revealed a fundamental crustal boundary bisecting the Ross Ice Shelf and imparting a duality to the Ross Ice Shelf systems, encompassing bathymetry, ocean circulation and ice flow history. The ROSETTA-Ice surveys were designed to increase the resolution of Ross Ice Shelf mapping from the 55 km RIGGS survey of the 1970s to a 10 km survey grid, flown over three years from New York Air National Guard LC130s. Radar, LiDAR, gravity and magnetic instruments provide a top to bottom profile of the ice shelf and the underlying seafloor, with 20 km resolution achieved in the first two survey seasons (2015 and 2016). ALAMO ocean-profiling floats deployed in the 2016 season are measuring the temperature and salinity of water entering and exiting the sub-ice water cavity. A significant east-west contrast in the character of the magnetic and gravity fields reveals that the lithospheric boundary between East and West Antarctica exists not at the base of the Transantarctic Mountains (TAM), as previously thought, but 300 km further east. The newly-identified boundary spatially coincides with the southward extension of the Central High, a rib of shallow basement identified in the Ross Sea. The East Antarctic side is characterized by lower amplitude magnetic anomalies and denser TAM-type lithosphere compared to the West Antarctic side. The crustal structure imparts a fundamental duality on the overlying ice and ocean, with deeper bathymetry and thinner ice on the East Antarctic side creating a larger sub-ice cavity for ocean circulation. The West Antarctic side has a shallower seabed, more restricted ocean access and a more complex history of

  8. Bimodal SLD Ice Accretion on a NACA 0012 Airfoil Model

    Science.gov (United States)

    Potapczuk, Mark; Tsao, Jen-Ching; King-Steen, Laura

    2016-01-01

    This presentation describes the results of ice accretion measurements on a NACA 0012 airfoil model, from the NASA Icing Research Tunnel, using an icing cloud composed of a bimodal distribution of Supercooled Large Droplets. The data consists of photographs, laser scans of the ice surface, and measurements of the mass of ice for each icing condition. The results of ice shapes accumulated as a result of exposure to an icing cloud with a bimodal droplet distribution were compared to the ice shapes resulting from an equivalent cloud composed of a droplet distribution with a standard bell curve shape.

  9. On Wave-Ice Interaction in the Arctic Marginal Ice Zone: Dispersion, Attenuation, and Ice Response

    Science.gov (United States)

    2016-06-01

    described in Thorndike et al. [1975]. Waves have not played a role in CICE because their influence is limited to the MIZ which was traditionally a... Thorndike et al, [1979] d(p) is area conserving, so that the integral over all ranges of ice property, p, is unity. � ()...most effected by lateral melt < O(30 m). Observations of FSD [Rothrock and Thorndike , 1984; Toyota et al., 2006], done through analysis of aerial

  10. Road icing forecasting and detecting system

    Science.gov (United States)

    Xu, Hongke; Zheng, Jinnan; Li, Peiqi; Wang, Qiucai

    2017-05-01

    Regard for the facts that the low accuracy and low real-time of the artificial observation to determine the road icing condition, and it is difficult to forecast icing situation, according to the main factors influencing the road-icing, and the electrical characteristics reflected by the pavement ice layer, this paper presents an innovative system, that is, ice-forecasting of the highway's dangerous section. The system bases on road surface water salinity measurements and pavement temperature measurement to calculate the freezing point of water and temperature change trend, and then predicts the occurrence time of road icing; using capacitance measurements to verdict the road surface is frozen or not; This paper expounds the method of using single chip microcomputer as the core of the control system and described the business process of the system.

  11. MODIS Snow and Sea Ice Products

    Science.gov (United States)

    Hall, Dorothy K.; Riggs, George A.; Salomonson, Vincent V.

    2004-01-01

    In this chapter, we describe the suite of Earth Observing System (EOS) Moderate-Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua snow and sea ice products. Global, daily products, developed at Goddard Space Flight Center, are archived and distributed through the National Snow and Ice Data Center at various resolutions and on different grids useful for different communities Snow products include binary snow cover, snow albedo, and in the near future, fraction of snow in a 5OO-m pixel. Sea ice products include ice extent determined with two different algorithms, and sea ice surface temperature. The algorithms used to develop these products are described. Both the snow and sea ice products, available since February 24,2000, are useful for modelers. Validation of the products is also discussed.

  12. IceProd 2 Usage Experience

    Science.gov (United States)

    Delventhal, D.; Schultz, D.; Diaz Velez, J. C.

    2017-10-01

    IceProd is a data processing and management framework developed by the IceCube Neutrino Observatory for processing of Monte Carlo simulations, detector data, and data driven analysis. It runs as a separate layer on top of grid and batch systems. This is accomplished by a set of daemons which process job workflow, maintaining configuration and status information on the job before, during, and after processing. IceProd can also manage complex workflow DAGs across distributed computing grids in order to optimize usage of resources. IceProd has recently been rewritten to increase its scaling capabilities, handle user analysis workflows together with simulation production, and facilitate the integration with 3rd party scheduling tools. IceProd 2, the second generation of IceProd, has been running in production for several months now. We share our experience setting up the system and things we’ve learned along the way.

  13. Design of an airborne P-band ice sounding radar

    DEFF Research Database (Denmark)

    Dall, Jørgen; Skou, Niels; Kusk, Anders

    2006-01-01

    is to test new ice sounding techniques, e.g. polarimetry, synthetic aperture processing, and coherent clutter suppression. A system analysis involving ice scattering models confirms that it is feasible to detect the bedrock through 4 km of ice and to detect deep ice layers. The ice sounder design features...

  14. National Ice Center Arctic Sea Ice Charts and Climatologies in Gridded Format

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The U.S. National Ice Center (NIC) is an inter-agency sea ice analysis and forecasting center comprised of the Department of Commerce/NOAA, the Department of...

  15. SmaggIce 2.0: Additional Capabilities for Interactive Grid Generation of Iced Airfoils

    Science.gov (United States)

    Kreeger, Richard E.; Baez, Marivell; Braun, Donald C.; Schilling, Herbert W.; Vickerman, Mary B.

    2008-01-01

    The Surface Modeling and Grid Generation for Iced Airfoils (SmaggIce) software toolkit has been extended to allow interactive grid generation for multi-element iced airfoils. The essential phases of an icing effects study include geometry preparation, block creation and grid generation. SmaggIce Version 2.0 now includes these main capabilities for both single and multi-element airfoils, plus an improved flow solver interface and a variety of additional tools to enhance the efficiency and accuracy of icing effects studies. An overview of these features is given, especially the new multi-element blocking strategy using the multiple wakes method. Examples are given which illustrate the capabilities of SmaggIce for conducting an icing effects study for both single and multi-element airfoils.

  16. Ice Motion and Topography Near Margin Areas of Kamb Ice Stream, Antarctica, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes ice motion and topography measurements that were taken by measuring movement and altitude of poles set in the West Antarctic Ice Shelf. The...

  17. Cook Inlet and Kenai Peninsula, Alaska ESI: ICE (Ice Extent Lines)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains locations of ice extent in Cook Inlet, Alaska. Vector lines in the data set represent 50 percent ice coverage. Location-specific type and...

  18. A review of the physics of ice surface friction and the development of ice skating.

    Science.gov (United States)

    Formenti, Federico

    2014-01-01

    Our walking and running movement patterns require friction between shoes and ground. The surface of ice is characterised by low friction in several naturally occurring conditions, and compromises our typical locomotion pattern. Ice skates take advantage of this slippery nature of ice; the first ice skates were made more than 4000 years ago, and afforded the development of a very efficient form of human locomotion. This review presents an overview of the physics of ice surface friction, and discusses the most relevant factors that can influence ice skates' dynamic friction coefficient. It also presents the main stages in the development of ice skating, describes the associated implications for exercise physiology, and shows the extent to which ice skating performance improved through history. This article illustrates how technical and materials' development, together with empirical understanding of muscle biomechanics and energetics, led to one of the fastest forms of human powered locomotion.

  19. IceBridge Radar L3 Tomographic Ice Thickness V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains Level-3 tomographic ice thickness measurements derived from data captured by the Center for Remote Sensing of Ice Sheets (CReSIS) Multichannel...

  20. Arctic sea ice decline contributes to thinning lake ice trend in northern Alaska

    Science.gov (United States)

    Alexeev, Vladimir; Arp, Christopher D.; Jones, Benjamin M.; Cai, Lei

    2016-01-01

    Field measurements, satellite observations, and models document a thinning trend in seasonal Arctic lake ice growth, causing a shift from bedfast to floating ice conditions. September sea ice concentrations in the Arctic Ocean since 1991 correlate well (r = +0.69,p Research and Forecasting model output produced a 7% decrease in lake ice growth when 2007/08 sea ice was imposed on 1991/92 climatology and a 9% increase in lake ice growth for the opposing experiment. Here, we clearly link early winter 'ocean-effect' snowfall and warming to reduced lake ice growth. Future reductions in sea ice extent will alter hydrological, biogeochemical, and habitat functioning of Arctic lakes and cause sub-lake permafrost thaw.

  1. Ice Draft and Ice Velocity Data in the Beaufort Sea, 1990-2003, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides measurement of sea ice draft (m) and the movement of sea ice (cm/s) over the continental shelf of the Eastern Beaufort Sea. The data set spans...

  2. Ice nucleation properties of mineral dusts

    OpenAIRE

    Steinke, Isabelle

    2013-01-01

    Ice nucleation in clouds has a significant impact on the global hydrological cycle as well as on the radiative budget of the Earth. The AIDA cloud chamber was used to investigate the ice nucleation efficiency of various atmospherically relevant mineral dusts. From experiments with Arizona Test Dust (ATD) a humidity and temperature dependent ice nucleation active surface site density parameterization was developed to describe deposition nucleation at temperatures above 220 K. Based...

  3. Elevator deflections on the icing process

    Science.gov (United States)

    Britton, Randall K.

    1990-01-01

    The effect of elevator deflection of the horizontal stabilizer for certain icing parameters is investigated. Elevator deflection can severely change the lower and upper leading-edge impingement limits, and ice can accrete on the elevator itself. Also, elevator deflection had practically no effect on the maximum local collection efficiency. It is shown that for severe icing conditions (large water droplets), elevator deflections that increase the projected height of the airfoil can significantly increase the total collection efficiency of the airfoil.

  4. 21 CFR 880.6050 - Ice bag.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ice bag. 880.6050 Section 880.6050 Food and Drugs....6050 Ice bag. (a) Identification. An ice bag is a device intended for medical purposes that is in the... the body. The device may include a holder that keeps the bag in place against an external area of the...

  5. Ice Storms in a Changing Climate

    Science.gov (United States)

    2016-06-01

    CHANGING CLIMATE by Jennifer M. McNitt June 2016 Thesis Advisor: Wendell Nuss Co-Advisor: David W. Titley THIS PAGE INTENTIONALLY LEFT...SUBTITLE ICE STORMS IN A CHANGING CLIMATE 5. FUNDING NUMBERS 6. AUTHOR(S) Jennifer M. McNitt 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS...increase in global temperatures, due to climate change, could affect the frequency, intensity, and geographic location of ice storms. Three known ice

  6. On the origin of the ice ages

    OpenAIRE

    Oerlemans, J.

    1984-01-01

    Ice sheet dynamics provide a possible explanation for the 100 kyr power in climatic records. Some numerical experiments presented here show that even the transition from an essentially ice-free earth to a glacial can be produced by a northern hemisphere ice-sheet model, provided that a slow general cooling on the northern hemisphere continents is imposed. Such a cooling could for example be the result of continental drift.

  7. Greenland Ice Shelves and Ice Tongues

    DEFF Research Database (Denmark)

    Reeh, Niels

    2017-01-01

    literature and physical properties are reviewed. There exists a difference between: (1) Floating glaciers in northern Greenland (>77°N) which experience bottom melting as their dominant ablation mechanism and calve relatively thin, but large (km-sized) tabular icebergs (‘ice islands’), and (2) Grounded...... glaciers further south (iceberg calving provides the dominant ablation mechanism. The relatively smaller iceberg discharge in northern Greenland is closely related to the occurrence of extended floating glacier sections, allowing bottom melting estimated at up to 10 m year−1 for locations...

  8. Icing Branch Current Research Activities in Icing Physics

    Science.gov (United States)

    Vargas, Mario

    2009-01-01

    Current development: A grid block transformation scheme which allows the input of grids in arbitrary reference frames, the use of mirror planes, and grids with relative velocities has been developed. A simple ice crystal and sand particle bouncing scheme has been included. Added an SLD splashing model based on that developed by William Wright for the LEWICE 3.2.2 software. A new area based collection efficiency algorithm will be incorporated which calculates trajectories from inflow block boundaries to outflow block boundaries. This method will be used for calculating and passing collection efficiency data between blade rows for turbo-machinery calculations.

  9. Possible Mechanisms for Turbofan Engine Ice Crystal Icing at High Altitude

    Science.gov (United States)

    Tsao, Jen-Ching; Struk, Peter M.; Oliver, Michael J.

    2016-01-01

    A thermodynamic model is presented to describe possible mechanisms of ice formation on unheated surfaces inside a turbofan engine compression system from fully glaciated ice crystal clouds often formed at high altitude near deep convective weather systems. It is shown from the analysis that generally there could be two distinct types of ice formation: (1) when the "surface freezing fraction" is in the range of 0 to 1, dominated by the freezing of water melt from fully or partially melted ice crystals, the ice structure is formed from accretion with strong adhesion to the surface, and (2) when the "surface melting fraction" is the range of 0 to 1, dominated by the further melting of ice crystals, the ice structure is formed from accumulation of un-melted ice crystals with relatively weak bonding to the surface. The model captures important qualitative trends of the fundamental ice-crystal icing phenomenon reported earlier (Refs. 1 and 2) from the research collaboration work by NASA and the National Research Council (NRC) of Canada. Further, preliminary analysis of test data from the 2013 full scale turbofan engine ice crystal icing test (Ref. 3) conducted in the NASA Glenn Propulsion Systems Laboratory (PSL) has also suggested that (1) both types of ice formation occurred during the test, and (2) the model has captured some important qualitative trend of turning on (or off) the ice crystal ice formation process in the tested engine low pressure compressor (LPC) targeted area under different icing conditions that ultimately would lead to (or suppress) an engine core roll back (RB) event.

  10. Sea ice roughness: the key for predicting Arctic summer ice albedo

    Science.gov (United States)

    Landy, J.; Ehn, J. K.; Tsamados, M.; Stroeve, J.; Barber, D. G.

    2017-12-01

    Although melt ponds on Arctic sea ice evolve in stages, ice with smoother surface topography typically allows the pond water to spread over a wider area, reducing the ice-albedo and accelerating further melt. Building on this theory, we simulated the distribution of meltwater on a range of statistically-derived topographies to develop a quantitative relationship between premelt sea ice surface roughness and summer ice albedo. Our method, previously applied to ICESat observations of the end-of-winter sea ice roughness, could account for 85% of the variance in AVHRR observations of the summer ice-albedo [Landy et al., 2015]. Consequently, an Arctic-wide reduction in sea ice roughness over the ICESat operational period (from 2003 to 2008) explained a drop in ice-albedo that resulted in a 16% increase in solar heat input to the sea ice cover. Here we will review this work and present new research linking pre-melt sea ice surface roughness observations from Cryosat-2 to summer sea ice albedo over the past six years, examining the potential of winter roughness as a significant new source of sea ice predictability. We will further evaluate the possibility for high-resolution (kilometre-scale) forecasts of summer sea ice albedo from waveform-level Cryosat-2 roughness data in the landfast sea ice zone of the Canadian Arctic. Landy, J. C., J. K. Ehn, and D. G. Barber (2015), Albedo feedback enhanced by smoother Arctic sea ice, Geophys. Res. Lett., 42, 10,714-10,720, doi:10.1002/2015GL066712.

  11. Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead

    Science.gov (United States)

    Kauko, Hanna M.; Taskjelle, Torbjørn; Assmy, Philipp; Pavlov, Alexey K.; Mundy, C. J.; Duarte, Pedro; Fernández-Méndez, Mar; Olsen, Lasse M.; Hudson, Stephen R.; Johnsen, Geir; Elliott, Ashley; Wang, Feiyue; Granskog, Mats A.

    2017-06-01

    The Arctic Ocean is rapidly changing from thicker multiyear to thinner first-year ice cover, with significant consequences for radiative transfer through the ice pack and light availability for algal growth. A thinner, more dynamic ice cover will possibly result in more frequent leads, covered by newly formed ice with little snow cover. We studied a refrozen lead (≤0.27 m ice) in drifting pack ice north of Svalbard (80.5-81.8°N) in May-June 2015 during the Norwegian young sea ICE expedition (N-ICE2015). We measured downwelling incident and ice-transmitted spectral irradiance, and colored dissolved organic matter (CDOM), particle absorption, ultraviolet (UV)-protecting mycosporine-like amino acids (MAAs), and chlorophyll a (Chl a) in melted sea ice samples. We found occasionally very high MAA concentrations (up to 39 mg m-3, mean 4.5 ± 7.8 mg m-3) and MAA to Chl a ratios (up to 6.3, mean 1.2 ± 1.3). Disagreement in modeled and observed transmittance in the UV range let us conclude that MAA signatures in CDOM absorption spectra may be artifacts due to osmotic shock during ice melting. Although observed PAR (photosynthetically active radiation) transmittance through the thin ice was significantly higher than that of the adjacent thicker ice with deep snow cover, ice algal standing stocks were low (≤2.31 mg Chl a m-2) and similar to the adjacent ice. Ice algal accumulation in the lead was possibly delayed by the low inoculum and the time needed for photoacclimation to the high-light environment. However, leads are important for phytoplankton growth by acting like windows into the water column.

  12. Determining the ice seasons severity during 1982-2015 using the ice extents sum as a new characteristic

    Science.gov (United States)

    Rjazin, Jevgeni; Pärn, Ove

    2016-04-01

    Sea ice is a key climate factor and it restricts considerably the winter navigation in sever seasons on the Baltic Sea. So determining ice conditions severity and describing ice cover behaviour at severe seasons interests scientists, engineers and navigation managers. The present study is carried out to determine the ice seasons severity degree basing on the ice seasons 1982 to 2015. A new integrative characteristic is introduced to describe the ice season severity. It is the sum of ice extents of the ice season id est the daily ice extents of the season are summed. The commonly used procedure to determine the ice season severity degree by the maximal ice extent is in this research compared to the new characteristic values. The remote sensing data on the ice concentrations on the Baltic Sea published in the European Copernicus Programme are used to obtain the severity characteristic values. The ice extents are calculated on these ice concentration data. Both the maximal ice extent of the season and a newly introduced characteristic - the ice extents sum are used to classify the winters with respect of severity. The most severe winter of the reviewed period is 1986/87. Also the ice seasons 1981/82, 1984/85, 1985/86, 1995/96 and 2002/03 are classified as severe. Only three seasons of this list are severe by both the criteria. They are 1984/85, 1985/86 and 1986/87. We interpret this coincidence as the evidence of enough-during extensive ice cover in these three seasons. In several winters, for example 2010/11 ice cover extended enough for some time, but did not endure. At few other ice seasons as 2002/03 the Baltic Sea was ice-covered in moderate extent, but the ice cover stayed long time. At 11 winters the ice extents sum differed considerably (> 10%) from the maximal ice extent. These winters yield one third of the studied ice seasons. The maximal ice extent of the season is simple to use and enables to reconstruct the ice cover history and to predict maximal ice

  13. Icing Impacts on Wind Energy Production

    DEFF Research Database (Denmark)

    Davis, Neil

    was developed for the identification of icing periods from the turbine power data and the nacelle wind speeds. This method was based on the spread of power production observations at cold temperatures that was not seen during warmer periods. Using the insights gained through the observational analysis...... and the turbine power loss. The model took the shape of a hierarchal model that combined a decision tree model, based on the existence of ice on the turbine blade, and two Generalized Additive Models (GAM). The GAM for periods where icing was forecast was found to include the terms wind speed, total ice mass...

  14. Ice nucleation triggered by negative pressure.

    Science.gov (United States)

    Marcolli, Claudia

    2017-11-30

    Homogeneous ice nucleation needs supercooling of more than 35 K to become effective. When pressure is applied to water, the melting and the freezing points both decrease. Conversely, melting and freezing temperatures increase under negative pressure, i.e. when water is stretched. This study presents an extrapolation of homogeneous ice nucleation temperatures from positive to negative pressures as a basis for further exploration of ice nucleation under negative pressure. It predicts that increasing negative pressure at temperatures below about 262 K eventually results in homogeneous ice nucleation while at warmer temperature homogeneous cavitation, i. e. bubble nucleation, dominates. Negative pressure occurs locally and briefly when water is stretched due to mechanical shock, sonic waves, or fragmentation. The occurrence of such transient negative pressure should suffice to trigger homogeneous ice nucleation at large supercooling in the absence of ice-nucleating surfaces. In addition, negative pressure can act together with ice-inducing surfaces to enhance their intrinsic ice nucleation efficiency. Dynamic ice nucleation can be used to improve properties and uniformity of frozen products by applying ultrasonic fields and might also be relevant for the freezing of large drops in rainclouds.

  15. Seismic explosion sources on an ice cap

    DEFF Research Database (Denmark)

    Shulgin, Alexey; Thybo, Hans

    2015-01-01

    crustal model can be modelled. A crucial challenge for applying the technique is to control the sources. Here, we present data that describe the efficiency of explosive sources in the ice cover. Analysis of the data shows, that the ice cap traps a significant amount of energy, which is observed......Controlled source seismic investigation of crustal structure below ice covers is an emerging technique. We have recently conducted an explosive refraction/wide-angle reflection seismic experiment on the ice cap in east-central Greenland. The data-quality is high for all shot points and a full...

  16. Ice load reducer for dams : laboratory tests

    Energy Technology Data Exchange (ETDEWEB)

    Lupien, R.; Cote, A.; Robert, A. [Institut de Recherche d' Hydro-Quebec, Varennes, PQ (Canada)

    2009-07-01

    Many studies have focused on measuring static ice loads on various hydraulic structures in Canada. This paper discussed a Hydro-Quebec research project whose main purpose was to harmonize the ice thrust value in load combinations for use in general hydraulic works or for specific cases. The objectives of the project were to obtain a better understanding of existing data and to characterize sites and their influence on ice thrust; study the structural mechanisms involved in the generation of ice thrust, their consequences on the structural behaviour of ice and the natural mitigating circumstances that may be offered by ice properties or site operating procedures; and examine the relevance of developing an ice load reducer for works that might not fit the harmonized design value. The paper presented the main research goals and ice load reducer goals, with particular focus on the four pipe samples that were planned, built and tested. The experimental program involved checking the pipe shape behaviour in terms of flexibility-stiffness; maximum deformations; maximum load reduction; permanent deformations; and, ability to shape recovering. The testing also involved examining the strength versus strain rate; creep versus strain rate; and creep capacity under biaxial state of tension and compression. It was concluded that the two phenomena involved in generation of ice thrust, notably thermal expansion and water level changes, had very low strain rates. 8 refs., 2 tabs., 16 figs.

  17. [Reflectance of sea ice in Liaodong Bay].

    Science.gov (United States)

    Xu, Zhan-tang; Yang, Yue-zhong; Wang, Gui-fen; Cao, Wen-xi; Kong, Xiang-peng

    2010-07-01

    In the present study, the relationships between sea ice albedo and the bidirectional reflectance distribution in Liaodong Bay were investigated. The results indicate that: (1) sea ice albedo alpha(lambda) is closely related to the components of sea ice, the higher the particulate concentration in sea ice surface is, the lower the sea ice albedo alpha(lambda) is. On the contrary, the higher the bubble concentration in sea ice is, the higher sea ice albedo alpha(lambda) is. (2) Sea ice albedo alpha(lambda) is similar to the bidirectional reflectance factor R(f) when the probe locates at nadir. The R(f) would increase with the increase in detector zenith theta, and the correlation between R(f) and the detector azimuth would gradually increase. When the theta is located at solar zenith 63 degrees, the R(f) would reach the maximum, and the strongest correlation is also shown between the R(f) and the detector azimuth. (3) Different types of sea ice would have the different anisotropic reflectance factors.

  18. Dynamics of colloidal particles in ice

    KAUST Repository

    Spannuth, Melissa

    2011-01-01

    We use x-ray photon correlation spectroscopy (XPCS) to probe the dynamics of colloidal particles in polycrystalline ice. During freezing, the dendritic ice morphology and rejection of particles from the ice created regions of high particle density, where some of the colloids were forced into contact and formed disordered aggregates. The particles in these high density regions underwent ballistic motion, with a characteristic velocity that increased with temperature. This ballistic motion is coupled with both stretched and compressed exponential decays of the intensity autocorrelation function. We suggest that this behavior could result from ice grain boundary migration. © 2011 American Institute of Physics.

  19. Viscosity of interfacial water regulates ice nucleation

    International Nuclear Information System (INIS)

    Li, Kaiyong; Chen, Jing; Zhang, Qiaolan; Zhang, Yifan; Xu, Shun; Zhou, Xin; Cui, Dapeng; Wang, Jianjun; Song, Yanlin

    2014-01-01

    Ice formation on solid surfaces is an important phenomenon in many fields, such as cloud formation and atmospheric icing, and a key factor for applications in preventing freezing. Here, we report temperature-dependent nucleation rates of ice for hydrophilic and hydrophobic surfaces. The results show that hydrophilic surface presents a lower ice nucleation rate. We develop a strategy to extract the thermodynamic parameters, J 0 and Γ, in the context of classical nucleation theory. From the extracted J 0 and Γ, we reveal the dominant role played by interfacial water. The results provide an insight into freezing mechanism on solid surfaces

  20. The IceCube Computing Infrastructure Model

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    Besides the big LHC experiments a number of mid-size experiments is coming online which need to define new computing models to meet the demands on processing and storage requirements of those experiments. We present the hybrid computing model of IceCube which leverages GRID models with a more flexible direct user model as an example of a possible solution. In IceCube a central datacenter at UW-Madison servers as Tier-0 with a single Tier-1 datacenter at DESY Zeuthen. We describe the setup of the IceCube computing infrastructure and report on our experience in successfully provisioning the IceCube computing needs.

  1. Deformation and failure of the ice bridge on the Wilkins Ice Shelf, Antarctica

    NARCIS (Netherlands)

    Humbert, A.; Gross, D.; Müller, R.; Braun, M.; van de Wal, R.S.W.; van den Broeke, M.R.; Vaughan, D.G.; van de Berg, W.J.

    2010-01-01

    A narrow bridge of floating ice that connected the Wilkins Ice Shelf, Antarctica, to two confining islands eventually collapsed in early April 2009. In the month preceding the collapse, we observed deformation of the ice bridge by means of satellite imagery and from an in situ GPS station.

  2. Assimilation of ice and water observations from SAR imagery to improve estimates of sea ice concentration

    Directory of Open Access Journals (Sweden)

    K. Andrea Scott

    2015-09-01

    Full Text Available In this paper, the assimilation of binary observations calculated from synthetic aperture radar (SAR images of sea ice is investigated. Ice and water observations are obtained from a set of SAR images by thresholding ice and water probabilities calculated using a supervised maximum likelihood estimator (MLE. These ice and water observations are then assimilated in combination with ice concentration from passive microwave imagery for the purpose of estimating sea ice concentration. Due to the fact that the observations are binary, consisting of zeros and ones, while the state vector is a continuous variable (ice concentration, the forward model used to map the state vector to the observation space requires special consideration. Both linear and non-linear forward models were investigated. In both cases, the assimilation of SAR data was able to produce ice concentration analyses in closer agreement with image analysis charts than when assimilating passive microwave data only. When both passive microwave and SAR data are assimilated, the bias between the ice concentration analyses and the ice concentration from ice charts is 19.78%, as compared to 26.72% when only passive microwave data are assimilated. The method presented here for the assimilation of SAR data could be applied to other binary observations, such as ice/water information from visual/infrared sensors.

  3. Inhibition of ice crystal growth in ice cream mix by gelatin hydrolysate.

    Science.gov (United States)

    Damodaran, Srinivasan

    2007-12-26

    The inhibition of ice crystal growth in ice cream mix by gelatin hydrolysate produced by papain action was studied. The ice crystal growth was monitored by thermal cycling between -14 and -12 degrees C at a rate of one cycle per 3 min. It is shown that the hydrolysate fraction containing peptides in the molecular weight range of about 2000-5000 Da exhibited the highest inhibitory activity on ice crystal growth in ice cream mix, whereas fractions containing peptides greater than 7000 Da did not inhibit ice crystal growth. The size distribution of gelatin peptides formed in the hydrolysate was influenced by the pH of hydrolysis. The optimum hydrolysis conditions for producing peptides with maximum ice crystal growth inhibitory activity was pH 7 at 37 degrees C for 10 min at a papain to gelatin ratio of 1:100. However, this may depend on the type and source of gelatin. The possible mechanism of ice crystal growth inhibition by peptides from gelatin is discussed. Molecular modeling of model gelatin peptides revealed that they form an oxygen triad plane at the C-terminus with oxygen-oxygen distances similar to those found in ice nuclei. Binding of this oxygen triad plane to the prism face of ice nuclei via hydrogen bonding appears to be the mechanism by which gelatin hydrolysate might be inhibiting ice crystal growth in ice cream mix.

  4. Thermodynamics of high-pressure ice polymorphs : ices III and V

    NARCIS (Netherlands)

    Tchijov, [No Value; Ayala, RB; Leon, GC; Nagornov, O

    Thermodynamic properties of high-pressure ice polymorphs, ices III and V, are studied theoretically. The results of TIP4P molecular dynamics simulations in the NPT ensemble are used to calculate the temperature dependence of the specific volume of ices III and V at pressures 0.25 and 0.5 GPa,

  5. Determining the ice-binding planes of antifreeze proteins by fluorescence-based ice plane affinity.

    Science.gov (United States)

    Basu, Koli; Garnham, Christopher P; Nishimiya, Yoshiyuki; Tsuda, Sakae; Braslavsky, Ido; Davies, Peter

    2014-01-15

    Antifreeze proteins (AFPs) are expressed in a variety of cold-hardy organisms to prevent or slow internal ice growth. AFPs bind to specific planes of ice through their ice-binding surfaces. Fluorescence-based ice plane affinity (FIPA) analysis is a modified technique used to determine the ice planes to which the AFPs bind. FIPA is based on the original ice-etching method for determining AFP-bound ice-planes. It produces clearer images in a shortened experimental time. In FIPA analysis, AFPs are fluorescently labeled with a chimeric tag or a covalent dye then slowly incorporated into a macroscopic single ice crystal, which has been preformed into a hemisphere and oriented to determine the a- and c-axes. The AFP-bound ice hemisphere is imaged under UV light to visualize AFP-bound planes using filters to block out nonspecific light. Fluorescent labeling of the AFPs allows real-time monitoring of AFP adsorption into ice. The labels have been found not to influence the planes to which AFPs bind. FIPA analysis also introduces the option to bind more than one differently tagged AFP on the same single ice crystal to help differentiate their binding planes. These applications of FIPA are helping to advance our understanding of how AFPs bind to ice to halt its growth and why many AFP-producing organisms express multiple AFP isoforms.

  6. Do pelagic grazers benefit from sea ice? Insights from the Antarctic sea ice proxy IPSO25

    Science.gov (United States)

    Schmidt, Katrin; Brown, Thomas A.; Belt, Simon T.; Ireland, Louise C.; Taylor, Kyle W. R.; Thorpe, Sally E.; Ward, Peter; Atkinson, Angus

    2018-04-01

    Sea ice affects primary production in polar regions in multiple ways. It can dampen water column productivity by reducing light or nutrient supply, provide a habitat for ice algae and condition the marginal ice zone (MIZ) for phytoplankton blooms on its seasonal retreat. The relative importance of three different carbon sources (sea ice derived, sea ice conditioned, non-sea-ice associated) for the polar food web is not well understood, partly due to the lack of methods that enable their unambiguous distinction. Here we analysed two highly branched isoprenoid (HBI) biomarkers to trace sea-ice-derived and sea-ice-conditioned carbon in Antarctic krill (Euphausia superba) and relate their concentrations to the grazers' body reserves, growth and recruitment. During our sampling in January-February 2003, the proxy for sea ice diatoms (a di-unsaturated HBI termed IPSO25, δ13C = -12.5 ± 3.3 ‰) occurred in open waters of the western Scotia Sea, where seasonal ice retreat was slow. In suspended matter from surface waters, IPSO25 was present at a few stations close to the ice edge, but in krill the marker was widespread. Even at stations that had been ice-free for several weeks, IPSO25 was found in krill stomachs, suggesting that they gathered the ice-derived algae from below the upper mixed layer. Peak abundances of the proxy for MIZ diatoms (a tri-unsaturated HBI termed HBI III, δ13C = -42.2 ± 2.4 ‰) occurred in regions of fast sea ice retreat and persistent salinity-driven stratification in the eastern Scotia Sea. Krill sampled in the area defined by the ice edge bloom likewise contained high amounts of HBI III. As indicators for the grazer's performance we used the mass-length ratio, size of digestive gland and growth rate for krill, and recruitment for the biomass-dominant calanoid copepods Calanoides acutus and Calanus propinquus. These indices consistently point to blooms in the MIZ as an important feeding ground for pelagic grazers. Even though ice

  7. Aircraft Icing Handbook. Volume 1

    Science.gov (United States)

    1991-03-01

    Maryland - . . . Kohiman Aviation, Lawrence , Kansas Ohio State University, Columbus, Ohio .I --- t-r 1-- - -t I.Q,,- t ../e . Pratt and Whitney...lower; about six percent at -22 ’F (-30 *C). 1.2.3 Variations with Season The summer or warm season months create large warm air masses which can...on Aircraft Surfaces," NASA TM 87184, May 1986. 2-54 Hausman , R.J. and Turnock, S.R., "Investigation of Surface Water Behavior During Glaze Ice

  8. Women of Ice and Fire

    DEFF Research Database (Denmark)

    challenges, exploits, yet also changes how we think of women and gender, not only in fantasy, but in Western culture in general. Divided into three sections addressing questions of adaptation from novel to television, female characters, and politics and female audience engagement within the GoT universe......, the interdisciplinary and international lineup of contributors analyze gender in relation to female characters and topics such as genre, sex, violence, adaptation, as well as fan reviews. The genre of fantasy was once considered a primarily male territory with male heroes. Women of Ice and Fire shows how the GoT...

  9. Ice Skating Instruction at the University of Illinois.

    Science.gov (United States)

    Christensen, Char; And Others

    1981-01-01

    The University of Illinois at Urbana-Champaign conducts a instructional ice skating program for its students and the community. Activities include: a figure skating club; a speed skating club; ice hockey program; and ice skating classes. (CJ)

  10. Multisensor Analyzed Sea Ice Extent - Northern Hemisphere (MASIE-NH)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Multisensor Analyzed Sea Ice Extent Northern Hemisphere (MASIE-NH) products provide measurements of daily sea ice extent and sea ice edge boundary for the...

  11. Ice, Ice, Baby: A Program for Sustained, Classroom-Based K-8 Teacher Professional Development

    Science.gov (United States)

    Hamilton, C.

    2009-12-01

    Ice, Ice, Baby is a K-8 science program created by the education team at the Center for the Remote Sensing of Ice Sheets (CReSIS), an NSF-funded science and technology center headquartered at the University of Kansas. The twenty-four hands-on activities, which constitute the Ice, Ice, Baby curriculum, were developed to help students understand the role of polar ice sheets in sea level rise. These activities, presented in classrooms by CReSIS' Educational Outreach Coordinator, demonstrate many of the scientific properties of ice, including displacement and density. Student journals are utilized with each lesson as a strategy for improving students' science process skills. Journals also help the instructor identify misconceptions, assess comprehension, and provide students with a year-long science reference log. Pre- and post- assessments are given to both teachers and students before and after the program, providing data for evaluation and improvement of the Ice, Ice, Baby program. While students are actively engaged in hands-on learning about the unusual topics of ice sheets, glaciers, icebergs and sea ice, the CReSIS' Educational Coordinator is able to model best practices in science education, such as questioning and inquiry-based methods of instruction. In this way, the Ice, Ice, Baby program also serves as ongoing, in-class, professional development for teachers. Teachers are also provided supplemental activities to do with their classes between CReSIS' visits to encourage additional science lessons, reinforce concepts taught in the Ice, Ice, Baby program, and to foster teachers' progression toward more reform-based science instruction.

  12. Bioinspired Materials for Controlling Ice Nucleation, Growth, and Recrystallization.

    Science.gov (United States)

    He, Zhiyuan; Liu, Kai; Wang, Jianjun

    2018-05-15

    Ice formation, mainly consisting of ice nucleation, ice growth, and ice recrystallization, is ubiquitous and crucial in wide-ranging fields from cryobiology to atmospheric physics. Despite active research for more than a century, the mechanism of ice formation is still far from satisfactory. Meanwhile, nature has unique ways of controlling ice formation and can provide resourceful avenues to unravel the mechanism of ice formation. For instance, antifreeze proteins (AFPs) protect living organisms from freezing damage via controlling ice formation, for example, tuning ice nucleation, shaping ice crystals, and inhibiting ice growth and recrystallization. In addition, AFP mimics can have applications in cryopreservation of cells, tissues, and organs, food storage, and anti-icing materials. Therefore, continuous efforts have been made to understand the mechanism of AFPs and design AFP inspired materials. In this Account, we first review our recent research progress in understanding the mechanism of AFPs in controlling ice formation. A Janus effect of AFPs on ice nucleation was discovered, which was achieved via selectively tethering the ice-binding face (IBF) or the non-ice-binding face (NIBF) of AFPs to solid surfaces and investigating specifically the effect of the other face on ice nucleation. Through molecular dynamics (MD) simulation analysis, we observed ordered hexagonal ice-like water structure atop the IBF and disordered water structure atop the NIBF. Therefore, we conclude that the interfacial water plays a critical role in controlling ice formation. Next, we discuss the design and fabrication of AFP mimics with capabilities in tuning ice nucleation and controlling ice shape and growth, as well as inhibiting ice recrystallization. For example, we tuned ice nucleation via modifying solid surfaces with supercharged unfolded polypeptides (SUPs) and polyelectrolyte brushes (PBs) with different counterions. We found graphene oxide (GO) and oxidized quasi

  13. Images de la statuaire archaïque dans les Aitia de Callimaque Archaic Sculpture in Callimachus’ Aitia Immagini della statuaria arcaica negli Aitia di Callimaco

    Directory of Open Access Journals (Sweden)

    Évelyne Prioux

    2011-07-01

    Full Text Available Plusieurs élégies rassemblées dans les Aitia de Callimaque s'attachent à expliquer les origines de tel ou tel culte ou d’une iconographie inattendue dont le temps a pu obscurcir la signification. Le recueil de Callimaque constitue ainsi un témoignage précieux sur la statuaire archaïque et sur sa réception auprès des érudits de l’époque hellénistique. Le présent article cherche à expliquer les choix opérés par Callimaque au sein de cette présentation de l’art archaïque : loin d'être disposées sans ordre, les notices rassemblées par Callimaque obéissent à des logiques de sélection et de classement que le lecteur moderne peut encore deviner. Par delà l’apparent désordre des fragments d’ecphraseis livrés par les découvertes papyrologiques, on perçoit que les poèmes que Callimaque a consacrés aux origines de la statuaire formaient probablement un tout signifiant. Le discours sur les statues sert ainsi de support à l’expression de positions éthiques, esthétiques et politiques : des images archaïques, telles que l’Apollon délien de Tectaios et d’Angélion ou une Héra de Samos, sont par exemple relues et réinterprétées dans l’intention d’inventer un passé susceptible de justifier les innovations politiques de la cour alexandrine et de les ancrer dans des interprétations iconographiques que le poète invente peut-être, bien qu’il feigne de les tirer de l’oubli. Pour ce faire, il applique aux images archaïques des techniques d’analyse allégorique qui sont sans doute directement inspirées par l'exégèse du texte homérique.Several fragmentary elegies of Callimachus’ Aitia were meant to explain the origins of a given cult or of a strange iconography whose meaning had been obscured by the passing of time. The Aitia are thus a very important source on archaic sculpture and on its reception in Hellenistic times. This paper attempts to explain how Callimachus selected the statues that

  14. Characterizing Arctic Sea Ice Topography Using High-Resolution IceBridge Data

    Science.gov (United States)

    Petty, Alek; Tsamados, Michel; Kurtz, Nathan; Farrell, Sinead; Newman, Thomas; Harbeck, Jeremy; Feltham, Daniel; Richter-Menge, Jackie

    2016-01-01

    We present an analysis of Arctic sea ice topography using high resolution, three-dimensional, surface elevation data from the Airborne Topographic Mapper, flown as part of NASA's Operation IceBridge mission. Surface features in the sea ice cover are detected using a newly developed surface feature picking algorithm. We derive information regarding the height, volume and geometry of surface features from 2009-2014 within the Beaufort/Chukchi and Central Arctic regions. The results are delineated by ice type to estimate the topographic variability across first-year and multi-year ice regimes.

  15. Bare ice fields developed in the inland part of the Antarctic ice sheet

    Directory of Open Access Journals (Sweden)

    Shuhei Takahashi

    1997-03-01

    Full Text Available Observations of a bare ice field were carried out at Seal Rock in the Sor Rondane area, East Antarctica. A large sublimation rate, 200 to 280mm/a, was observed on the bare ice field. Air temperature on the bare ice was about 1℃ higher than that on the snow surface. The large sublimation rate was explained from the low albedo of bare ice; its value was roughly estimated from heat budget considerations. The bare ice fields were classified into 4 types according to origin.

  16. State of Arctic Sea Ice North of Svalbard during N-ICE2015

    Science.gov (United States)

    Rösel, Anja; King, Jennifer; Gerland, Sebastian

    2016-04-01

    The N-ICE2015 cruise, led by the Norwegian Polar Institute, was a drift experiment with the research vessel R/V Lance from January to June 2015, where the ship started the drift North of Svalbard at 83°14.45' N, 21°31.41' E. The drift was repeated as soon as the vessel drifted free. Altogether, 4 ice stations where installed and the complex ocean-sea ice-atmosphere system was studied with an interdisciplinary Approach. During the N-ICE2015 cruise, extensive ice thickness and snow depth measurements were performed during both, winter and summer conditions. Total ice and snow thickness was measured with ground-based and airborne electromagnetic instruments; snow depth was measured with a GPS snow depth probe. Additionally, ice mass balance and snow buoys were deployed. Snow and ice thickness measurements were performed on repeated transects to quantify the ice growth or loss as well as the snow accumulation and melt rate. Additionally, we collected independent values on surveys to determine the general ice thickness distribution. Average snow depths of 32 cm on first year ice, and 52 cm on multi-year ice were measured in January, the mean snow depth on all ice types even increased until end of March to 49 cm. The average total ice and snow thickness in winter conditions was 1.92 m. During winter we found a small growth rate on multi-year ice of about 15 cm in 2 months, due to above-average snow depths and some extraordinary storm events that came along with mild temperatures. In contrast thereto, we also were able to study new ice formation and thin ice on newly formed leads. In summer conditions an enormous melt rate, mainly driven by a warm Atlantic water inflow in the marginal ice zone, was observed during two ice stations with melt rates of up to 20 cm per 24 hours. To reinforce the local measurements around the ship and to confirm their significance on a larger scale, we compare them to airborne thickness measurements and classified SAR-satellite scenes. The

  17. Ocean Profile Measurements During the Seasonal Ice Zone Reconnaissance Surveys

    Science.gov (United States)

    2014-09-30

    ice cover in 2014. The consequent reduced melting early in the summer delays the onset of sea - ice - albedo feed back in accelerating melt throughout the...Chukchi sea seasonal sea ice zone (SIZ) utilizing US Coast Guard Arctic Domain Awareness (ADA) flights of opportunity. This report covers our grant...region between maximum winter sea ice extent and minimum summer sea ice extent. As such, it contains the full range of positions of the marginal ice

  18. The lunar thermal ice pump

    Energy Technology Data Exchange (ETDEWEB)

    Schorghofer, Norbert [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii, Honolulu, HI 96822 (United States); Aharonson, Oded, E-mail: norbert@hawaii.edu [Helen Kimmel Center for Planetary Science, Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, 76100 (Israel)

    2014-06-20

    It has long been suggested that water ice can exist in extremely cold regions near the lunar poles, where sublimation loss is negligible. The geographic distribution of H-bearing regolith shows only a partial or ambiguous correlation with permanently shadowed areas, thus suggesting that another mechanism may contribute to locally enhancing water concentrations. We show that under suitable conditions, water molecules can be pumped down into the regolith by day-night temperature cycles, leading to an enrichment of H{sub 2}O in excess of the surface concentration. Ideal conditions for pumping are estimated and found to occur where the mean surface temperature is below 105 K and the peak surface temperature is above 120 K. These conditions complement those of the classical cold traps that are roughly defined by peak temperatures lower than 120 K. On the present-day Moon, an estimated 0.8% of the global surface area experiences such temperature variations. Typically, pumping occurs on pole-facing slopes in small areas, but within a few degrees of each pole the equator-facing slopes are preferred. Although pumping of water molecules is expected over cumulatively large areas, the absolute yield of this pump is low; at best, a few percent of the H{sub 2}O delivered to the surface could have accumulated in the near-surface layer in this way. The amount of ice increases with vapor diffusivity and is thus higher in the regolith with large pore spaces.

  19. MASS BALANCE CHANGES AND ICE DYNAMICS OF GREENLAND AND ANTARCTIC ICE SHEETS FROM LASER ALTIMETRY

    Directory of Open Access Journals (Sweden)

    G. S. Babonis

    2016-06-01

    Full Text Available During the past few decades the Greenland and Antarctic ice sheets have lost ice at accelerating rates, caused by increasing surface temperature. The melting of the two big ice sheets has a big impact on global sea level rise. If the ice sheets would melt down entirely, the sea level would rise more than 60 m. Even a much smaller rise would cause dramatic damage along coastal regions. In this paper we report about a major upgrade of surface elevation changes derived from laser altimetry data, acquired by NASA’s Ice, Cloud and land Elevation Satellite mission (ICESat and airborne laser campaigns, such as Airborne Topographic Mapper (ATM and Land, Vegetation and Ice Sensor (LVIS. For detecting changes in ice sheet elevations we have developed the Surface Elevation Reconstruction And Change detection (SERAC method. It computes elevation changes of small surface patches by keeping the surface shape constant and considering the absolute values as surface elevations. We report about important upgrades of earlier results, for example the inclusion of local ice caps and the temporal extension from 1993 to 2014 for the Greenland Ice Sheet and for a comprehensive reconstruction of ice thickness and mass changes for the Antarctic Ice Sheets.

  20. Ice bridges and ridges in the Maxwell-EB sea ice rheology

    Directory of Open Access Journals (Sweden)

    V. Dansereau

    2017-09-01

    Full Text Available This paper presents a first implementation of a new rheological model for sea ice on geophysical scales. This continuum model, called Maxwell elasto-brittle (Maxwell-EB, is based on a Maxwell constitutive law, a progressive damage mechanism that is coupled to both the elastic modulus and apparent viscosity of the ice cover and a Mohr–Coulomb damage criterion that allows for pure (uniaxial and biaxial tensile strength. The model is tested on the basis of its capability to reproduce the complex mechanical and dynamical behaviour of sea ice drifting through a narrow passage. Idealized as well as realistic simulations of the flow of ice through Nares Strait are presented. These demonstrate that the model reproduces the formation of stable ice bridges as well as the stoppage of the flow, a phenomenon occurring within numerous channels of the Arctic. In agreement with observations, the model captures the propagation of damage along narrow arch-like kinematic features, the discontinuities in the velocity field across these features dividing the ice cover into floes, the strong spatial localization of the thickest, ridged ice, the presence of landfast ice in bays and fjords and the opening of polynyas downstream of the strait. The model represents various dynamical behaviours linked to an overall weakening of the ice cover and to the shorter lifespan of ice bridges, with implications in terms of increased ice export through narrow outflow pathways of the Arctic.

  1. Ice bridges and ridges in the Maxwell-EB sea ice rheology

    Science.gov (United States)

    Dansereau, Véronique; Weiss, Jérôme; Saramito, Pierre; Lattes, Philippe; Coche, Edmond

    2017-09-01

    This paper presents a first implementation of a new rheological model for sea ice on geophysical scales. This continuum model, called Maxwell elasto-brittle (Maxwell-EB), is based on a Maxwell constitutive law, a progressive damage mechanism that is coupled to both the elastic modulus and apparent viscosity of the ice cover and a Mohr-Coulomb damage criterion that allows for pure (uniaxial and biaxial) tensile strength. The model is tested on the basis of its capability to reproduce the complex mechanical and dynamical behaviour of sea ice drifting through a narrow passage. Idealized as well as realistic simulations of the flow of ice through Nares Strait are presented. These demonstrate that the model reproduces the formation of stable ice bridges as well as the stoppage of the flow, a phenomenon occurring within numerous channels of the Arctic. In agreement with observations, the model captures the propagation of damage along narrow arch-like kinematic features, the discontinuities in the velocity field across these features dividing the ice cover into floes, the strong spatial localization of the thickest, ridged ice, the presence of landfast ice in bays and fjords and the opening of polynyas downstream of the strait. The model represents various dynamical behaviours linked to an overall weakening of the ice cover and to the shorter lifespan of ice bridges, with implications in terms of increased ice export through narrow outflow pathways of the Arctic.

  2. Ice-sheet flow conditions deduced from mechanical tests of ice core

    DEFF Research Database (Denmark)

    Miyamoto, Atsushi; Narita, Hideki; Hondoh, Takeo

    1999-01-01

    Uniaxial compression tests were performed on samples of the Greenland Ice Core Project (GRIP) deep ice core, both in the field and later in a cold-room laboratory, in order to understand the ice-flow behavior of large ice sheets. Experiments were conducted under conditions of constant strain rate....... It was revealed that cloudy bands affect ice-deformation processes, but the details remain unclear. Udgivelsesdato: June......Uniaxial compression tests were performed on samples of the Greenland Ice Core Project (GRIP) deep ice core, both in the field and later in a cold-room laboratory, in order to understand the ice-flow behavior of large ice sheets. Experiments were conducted under conditions of constant strain rate......-core samples with basal planes parallel to the horizontal plane of the ice sheet. The ice-flow enhancement factors show a gradual increase with depth down to approximately 2000 m. These results can be interpreted in terms of an increase in the fourth-order Schmid factor. Below 2000 m depth, the flow...

  3. Ice Caps and Ice Belts: The Effects of Obliquity on Ice−Albedo Feedback

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Brian E. J. [Department of Atmospheric and Environmental Sciences, University at Albany (State University of New York), 1400 Washington Avenue, Albany, NY 12222 (United States); Cronin, Timothy W. [Program in Atmospheres, Oceans, and Climate, Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Bitz, Cecilia M., E-mail: brose@albany.edu [Department of Atmospheric Sciences, MS 351640, University of Washington, Seattle, WA 98195-1640 (United States)

    2017-09-01

    Planetary obliquity determines the meridional distribution of the annual mean insolation. For obliquity exceeding 55°, the weakest insolation occurs at the equator. Stable partial snow and ice cover on such a planet would be in the form of a belt about the equator rather than polar caps. An analytical model of planetary climate is used to investigate the stability of ice caps and ice belts over the widest possible range of parameters. The model is a non-dimensional diffusive Energy Balance Model, representing insolation, heat transport, and ice−albedo feedback on a spherical planet. A complete analytical solution for any obliquity is given and validated against numerical solutions of a seasonal model in the “deep-water” regime of weak seasonal ice line migration. Multiple equilibria and unstable transitions between climate states (ice-free, Snowball, or ice cap/belt) are found over wide swaths of parameter space, including a “Large Ice-Belt Instability” and “Small Ice-Belt Instability” at high obliquity. The Snowball catastrophe is avoided at weak radiative forcing in two different scenarios: weak albedo feedback and inefficient heat transport (favoring stable partial ice cover), or efficient transport at high obliquity (favoring ice-free conditions). From speculative assumptions about distributions of planetary parameters, three-fourths to four-fifths of all planets with stable partial ice cover should be in the form of Earth-like polar caps.

  4. Variability and Trends in Sea Ice Extent and Ice Production in the Ross Sea

    Science.gov (United States)

    Comiso, Josefino; Kwok, Ronald; Martin, Seelye; Gordon, Arnold L.

    2011-01-01

    Salt release during sea ice formation in the Ross Sea coastal regions is regarded as a primary forcing for the regional generation of Antarctic Bottom Water. Passive microwave data from November 1978 through 2008 are used to examine the detailed seasonal and interannual characteristics of the sea ice cover of the Ross Sea and the adjacent Bellingshausen and Amundsen seas. For this period the sea ice extent in the Ross Sea shows the greatest increase of all the Antarctic seas. Variability in the ice cover in these regions is linked to changes in the Southern Annular Mode and secondarily to the Antarctic Circumpolar Wave. Over the Ross Sea shelf, analysis of sea ice drift data from 1992 to 2008 yields a positive rate of increase in the net ice export of about 30,000 sq km/yr. For a characteristic ice thickness of 0.6 m, this yields a volume transport of about 20 cu km/yr, which is almost identical, within error bars, to our estimate of the trend in ice production. The increase in brine rejection in the Ross Shelf Polynya associated with the estimated increase with the ice production, however, is not consistent with the reported Ross Sea salinity decrease. The locally generated sea ice enhancement of Ross Sea salinity may be offset by an increase of relatively low salinity of the water advected into the region from the Amundsen Sea, a consequence of increased precipitation and regional glacial ice melt.

  5. Stable isotope analysis in ice core paleoclimatology

    International Nuclear Information System (INIS)

    Bertler, N.A.N.

    2015-01-01

    Ice cores from New Zealand and the Antarctic margin provide an excellent means of addressing the lack of longer-term climate observations in the Southern Hemisphere with near instrumental quality. Ice core records provide an annual-scale, 'instrumental-quality' baseline of atmospheric temperature and circulation changes back many thousands of years. (author).

  6. Stable isotope analysis in ice core paleoclimatology

    International Nuclear Information System (INIS)

    Bertler, N.A.N.

    2014-01-01

    Ice cores from New Zealand and the Antarctic margin provide an excellent means of addressing the lack of longer-term climate observations in the Southern Hemisphere with near instrumental quality. Ice core records provide an annual-scale, 'instrumental-quality' baseline of atmospheric temperature and circulation changes back many thousands of years. (author)

  7. UV effects on bottom ice algae

    International Nuclear Information System (INIS)

    Ryan, K.; Buckley, B.

    1993-01-01

    Antarctic sea ice can be surprisingly transparent to UV radiation, particularly during spring when ozone depletion reaches a maximum. A 5% reduction in photosynthetic production was observed in laboratory experiments for UVB levels expected under the ice at this time. In situ studies modifying the UVB radiation falling onto algae were inconclusive. (author). 5 refs

  8. Yield surface evolution for columnar ice

    Science.gov (United States)

    Zhou, Zhiwei; Ma, Wei; Zhang, Shujuan; Mu, Yanhu; Zhao, Shunpin; Li, Guoyu

    A series of triaxial compression tests, which has capable of measuring the volumetric strain of the sample, were conducted on columnar ice. A new testing approach of probing the experimental yield surface was performed from a single sample in order to investigate yield and hardening behaviors of the columnar ice under complex stress states. Based on the characteristic of the volumetric strain, a new method of defined the multiaxial yield strengths of the columnar ice is proposed. The experimental yield surface remains elliptical shape in the stress space of effective stress versus mean stress. The effect of temperature, loading rate and loading path in the initial yield surface and deformation properties of the columnar ice were also studied. Subsequent yield surfaces of the columnar ice have been explored by using uniaxial and hydrostatic paths. The evolution of the subsequent yield surface exhibits significant path-dependent characteristics. The multiaxial hardening law of the columnar ice was established experimentally. A phenomenological yield criterion was presented for multiaxial yield and hardening behaviors of the columnar ice. The comparisons between the theoretical and measured results indicate that this current model is capable of giving a reasonable prediction for the multiaxial yield and post-yield properties of the columnar ice subjected to different temperature, loading rate and path conditions.

  9. Ice age plant refugia in East Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby

    1979-01-01

    From the distribution of plants it has been inferred by some botanists that ice-free areas existed in East Greenland accommodating a flora which survived one or several ice ages in the area. Comparing this evidence with recent information on the chronology of glaciations and post-glacial vegetation...

  10. Greenland ice sheet mass balance: a review

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Aschwanden, Andy; Bjørk, Anders A.

    2015-01-01

    Over the past quarter of a century the Arctic has warmed more than any other region on Earth, causing a profound impact on the Greenland ice sheet (GrIS) and its contribution to the rise in global sea level. The loss of ice can be partitioned into processes related to surface mass balance...

  11. De-Icing Salts and the Environment.

    Science.gov (United States)

    Massachusetts Audubon Society, Lincoln.

    Reported is an examination of the use and effects of chlorides as de-icing products for removal of snow and ice from roads immediately following storms. Increasing evidence of detrimental side effects led to a closer look and more careful evaluation of the overall significance of the so-called "bare pavement maintenance." The side…

  12. Tuning Ice Nucleation with Supercharged Polypeptides

    NARCIS (Netherlands)

    Yang, Huige; Ma, Chao; Li, Kaiyong; Liu, Kai; Loznik, Mark; Teeuwen, Rosalie; van Hest, Jan C. M.; Zhou, Xin; Herrmann, Andreas; Wang, Jianjun

    2016-01-01

    Supercharged unfolded polypeptides (SUPs) are exploited for controlling ice nucleation via tuning the nature of charge and charge density of SUPs. The results show that positively charged SUPs facilitate ice nucleation, while negatively charged ones suppress it. Moreover, the charge density of the

  13. Polar bears and sea ice habitat change

    Science.gov (United States)

    Durner, George M.; Atwood, Todd C.; Butterworth, Andy

    2017-01-01

    The polar bear (Ursus maritimus) is an obligate apex predator of Arctic sea ice and as such can be affected by climate warming-induced changes in the extent and composition of pack ice and its impacts on their seal prey. Sea ice declines have negatively impacted some polar bear subpopulations through reduced energy input because of loss of hunting habitats, higher energy costs due to greater ice drift, ice fracturing and open water, and ultimately greater challenges to recruit young. Projections made from the output of global climate models suggest that polar bears in peripheral Arctic and sub-Arctic seas will be reduced in numbers or become extirpated by the end of the twenty-first century if the rate of climate warming continues on its present trajectory. The same projections also suggest that polar bears may persist in the high-latitude Arctic where heavy multiyear sea ice that has been typical in that region is being replaced by thinner annual ice. Underlying physical and biological oceanography provides clues as to why polar bear in some regions are negatively impacted, while bears in other regions have shown no apparent changes. However, continued declines in sea ice will eventually challenge the survival of polar bears and efforts to conserve them in all regions of the Arctic.

  14. Cesium-137 contamination in Arctic Ocean ice

    International Nuclear Information System (INIS)

    Meese, D.; Tucker, W.; Cooper, L.; Larsen, I.L.; Grebmeier, J.

    1995-01-01

    Sea ice and ice-borne sediment samples were collected across the western Arctic basin on the joint US/Canada Arctic Ocean Section during August 1994. Samples were processed on board and returned at the completion of the cruise to Oak Ridge National Laboratory for analysis. Sediment was observed on the surface and in the ice from the southern ice limit in the Chukchi Sea to the North Pole. Preliminary results on the ice-borne sediment samples show widespread elevated concentrations of 137 Cs, ranging from 4.9 to 73 mBq g dry weight -1 . An analysis of the measurements indicate that sea ice is primary transport mechanism by which contaminated sediments are redistributed throughout the Arctic Ocean and possibly exported into the Greenland Sea and North Atlantic through Fram Strait. The wide variability in the ice-borne sediment concentrations of 137 Cs measured along the transect argues that contaminants incorporated on the Siberian shelves can follow much more variable trajectories than is suggested by mean ice drift calculations. 2 figs

  15. Performance evaluation of snow and ice plows.

    Science.gov (United States)

    2015-11-01

    Removal of ice and snow from road surfaces is a critical task in the northern tier of the United States, : including Illinois. Highways with high levels of traffic are expected to be cleared of snow and ice quickly : after each snow storm. This is ne...

  16. Modeling Europa's Ice-Ocean Interface

    Science.gov (United States)

    Elsenousy, A.; Vance, S.; Bills, B. G.

    2014-12-01

    This work focuses on modeling the ice-ocean interface on Jupiter's Moon (Europa); mainly from the standpoint of heat and salt transfer relationship with emphasis on the basal ice growth rate and its implications to Europa's tidal response. Modeling the heat and salt flux at Europa's ice/ocean interface is necessary to understand the dynamics of Europa's ocean and its interaction with the upper ice shell as well as the history of active turbulence at this area. To achieve this goal, we used McPhee et al., 2008 parameterizations on Earth's ice/ocean interface that was developed to meet Europa's ocean dynamics. We varied one parameter at a time to test its influence on both; "h" the basal ice growth rate and on "R" the double diffusion tendency strength. The double diffusion tendency "R" was calculated as the ratio between the interface heat exchange coefficient αh to the interface salt exchange coefficient αs. Our preliminary results showed a strong double diffusion tendency R ~200 at Europa's ice-ocean interface for plausible changes in the heat flux due to onset or elimination of a hydrothermal activity, suggesting supercooling and a strong tendency for forming frazil ice.

  17. Simple Cloud Chambers Using Gel Ice Packs

    Science.gov (United States)

    Kamata, Masahiro; Kubota, Miki

    2012-01-01

    Although cloud chambers are highly regarded as teaching aids for radiation education, school teachers have difficulty in using cloud chambers because they have to prepare dry ice or liquid nitrogen before the experiment. We developed a very simple and inexpensive cloud chamber that uses the contents of gel ice packs which can substitute for dry…

  18. 78 FR 15876 - Activation of Ice Protection

    Science.gov (United States)

    2013-03-13

    ...-0675; Amendment No. 121-363] RIN 2120-AJ43 Activation of Ice Protection AGENCY: Federal Aviation... On August 22, 2011, the FAA published a final rule entitled, ``Activation of Ice Protection,'' (76 FR... protection system. The FAA inadvertently wrote the amendatory language incorrectly to say that we were...

  19. Balance velocities of the Greenland ice sheet

    DEFF Research Database (Denmark)

    Joughin, I.; Fahnestock, M.; Ekholm, Simon

    1997-01-01

    We present a map of balance velocities for the Greenland ice sheet. The resolution of the underlying DEM, which was derived primarily from radar altimetery data, yields far greater detail than earlier balance velocity estimates for Greenland. The velocity contours reveal in striking detail......, the balance map is useful for ice-sheet modelling, mass balance studies, and field planning....

  20. We Scream for Nano Ice Cream

    Science.gov (United States)

    Jones, M. Gail; Krebs, Denise L.; Banks, Alton J.

    2011-01-01

    There is a wide range of new products emerging from nanotechnology, and "nano ice cream" is an easy one that you can use to teach topics from surface area to volume applications. In this activity, students learn how ice cream can be made smoother and creamier tasting through nanoscience. By using liquid nitrogen to cool the cream mixture, students…

  1. Major new sources of biological ice nuclei

    Science.gov (United States)

    Moffett, B. F.; Hill, T.; Henderson-Begg, S. K.

    2009-12-01

    Almost all research on biological ice nucleation has focussed on a limited number of bacteria. Here we characterise several major new sources of biogenic ice nuclei. These include mosses, hornworts, liverworts and cyanobacteria. Ice nucleation in the eukaryotic bryophytes appears to be ubiquitous. The temperature at which these organisms nucleate is that at which the difference in vapour pressure over ice and water is at or close to its maximum. At these temperatures (-8 to -18 degrees C) ice will grow at the expense of supercooled water. These organisms are dependent for their water on occult precipitation - fog, dew and cloudwater which by its nature is not collected in conventional rain gauges. Therefore we suggest that these organism produce ice nuclei as a water harvesting mechanism. Since the same mechanism would also drive the Bergeron-Findeisen process, and as moss is known to become airborne, these nuclei may have a role in the initiation of precipitation. The properties of these ice nuclei are very different from the well characterised bacterial nuclei. We will also present DNA sequence data showing that, although related, the proteins responsible are only very distantly related to the classical bacterial ice nuclei.

  2. Ice formation in subglacial Lake Vostok, Central Antarctica

    Science.gov (United States)

    Souchez, R.; Petit, J. R.; Tison, J.-L.; Jouzel, J.; Verbeke, V.

    2000-09-01

    The investigation of chemical and isotopic properties in the lake ice from the Vostok ice core gives clues to the mechanisms involved in ice formation within the lake. A small lake water salinity can be reasonably deduced from the chemical data. Possible implications for the water circulation of Lake Vostok are developed. The characteristics of the isotopic composition of the lake ice indicate that ice formation in Lake Vostok occurred by frazil ice crystal generation due to supercooling as a consequence of rising waters and a possible contrast in water salinity. Subsequent consolidation of the developed loose ice crystals results in the accretion of ice to the ceiling of the lake.

  3. Modelling the future of the arctic sea ice cover

    OpenAIRE

    Myklebust, Erik Bryhn

    2017-01-01

    Record lows in sea ice cover have recently sparked new interest in the small ice cap instability. The change in albedo when sea ice becomes open water introduces a nonlinearity called the ice-albedo feedback. Forcing a joint energy- balance and sea ice model can lead to unstable ice caps in certain parameter regimes. When the ice caps are unstable, a small perturbation will initiate a tipping point in the sea ice cover. For tipping points in general, a number of studies have pointed out that ...

  4. Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice Sheet

    Science.gov (United States)

    Stibal, Marek; Box, Jason E.; Cameron, Karen A.; Langen, Peter L.; Yallop, Marian L.; Mottram, Ruth H.; Khan, Alia L.; Molotch, Noah P.; Chrismas, Nathan A. M.; Calı Quaglia, Filippo; Remias, Daniel; Smeets, C. J. P. Paul; van den Broeke, Michiel R.; Ryan, Jonathan C.; Hubbard, Alun; Tranter, Martyn; van As, Dirk; Ahlstrøm, Andreas P.

    2017-11-01

    Surface ablation of the Greenland ice sheet is amplified by surface darkening caused by light-absorbing impurities such as mineral dust, black carbon, and pigmented microbial cells. We present the first quantitative assessment of the microbial contribution to the ice sheet surface darkening, based on field measurements of surface reflectance and concentrations of light-absorbing impurities, including pigmented algae, during the 2014 melt season in the southwestern part of the ice sheet. The impact of algae on bare ice darkening in the study area was greater than that of nonalgal impurities and yielded a net albedo reduction of 0.038 ± 0.0035 for each algal population doubling. We argue that algal growth is a crucial control of bare ice darkening, and incorporating the algal darkening effect will improve mass balance and sea level projections of the Greenland ice sheet and ice masses elsewhere.

  5. Simulation of an extended surface detector IceVeto for IceCube-Gen2

    Energy Technology Data Exchange (ETDEWEB)

    Hansmann, Tim; Auffenberg, Jan; Haack, Christian; Hansmann, Bengt; Kemp, Julian; Konietz, Richard; Leuner, Jakob; Raedel, Leif; Stahlberg, Martin; Schoenen, Sebastian; Wiebusch, Christopher [III. Physikalisches Institut B, RWTH Aachen University (Germany); Collaboration: IceCube-Collaboration

    2016-07-01

    IceCube is a neutrino observatory located at the geographic South Pole. The main backgrounds for IceCube's primary goal, the measurement of astrophysical neutrinos, are muons and neutrinos from cosmic-ray air showers in the Earth's atmosphere. Strong supression of these backgrounds from the Southern hemisphere has been demonstrated by coincident detection of these air showers with the IceTop surface detector. For an extended instrument, IceCube-Gen2, it is considered to build an enlarged surface array, IceVeto, that will improve the detection capabilities of coincident air showers. We will present simulation studies to estimate the IceVeto capabilities to optimize the IceCube-Gen2 design.

  6. Response timescales for martian ice masses and implications for ice flow on Mars

    DEFF Research Database (Denmark)

    Koutnik, Michelle Rebecca; Waddington, E.D.; Winebrener, D.P.

    2013-01-01

    a predictable shape, which is a function of ice temperature, ice rheology, and surface mass-exchange rate. In addition, the time for surface-shape adjustment is shorter than the characteristic time for significant deformation or displacement of internal layers within a flowing ice mass; as a result, surface......On Earth and on Mars, ice masses experience changes in precipitation, temperature, and radiation. In a new climate state, flowing ice masses will adjust in length and in thickness, and this response toward a new steady state has a characteristic timescale. However, a flowing ice mass has...... topography is more diagnostic of flow than are internal-layer shapes. Because the shape of Gemina Lingula, North Polar Layered Deposits indicates that it flowed at some time in the past, we use its current topography to infer characteristics of those past ice conditions, or past climate conditions, in which...

  7. Factors Affecting the Changes of Ice Crystal Form in Ice Cream

    Science.gov (United States)

    Wang, Xin; Watanabe, Manabu; Suzuki, Toru

    In this study, the shape of ice crystals in ice cream was quantitatively evaluated by introducing fractal analysis. A small droplet of commercial ice cream mix was quickly cooled to about -30°C on the cold stage of microscope. Subsequently, it was heated to -5°C or -10°C and then held for various holding time. Based on the captured images at each holding time, the cross-sectional area and the length of circumference for each ice crystal were measured to calculate fractal dimension using image analysis software. The results showed that the ice crystals were categorized into two groups, e.g. simple-shape and complicated-shape, according to their fractal dimensions. The fractal dimension of ice crystals became lower with increasing holding time and holding temperature. It was also indicated that the growing rate of complicated-shape ice crystals was relatively higher because of aggregation.

  8. Ocean wave generation by collapsing ice shelves

    Science.gov (United States)

    Macayeal, D. R.; Bassis, J. N.; Okal, E. A.; Aster, R. C.; Cathles, L. M.

    2008-12-01

    The 28-29 February, 2008, break-up of the Wilkins Ice Shelf, Antarctica, exemplifies the now-familiar, yet largely unexplained pattern of explosive ice-shelf break-up. While environmental warming is a likely ultimate cause of explosive break-up, several key aspects of their short-term behavior need to be explained: (1) The abrupt, near-simultaneous onset of iceberg calving across long spans of the ice front margin; (2) High outward drift velocity (about 0.3 m/s) of a leading phalanx of tabular icebergs that originate from the seaward edge of the intact ice shelf prior to break-up; (3) Rapid coverage of the ocean surface in the wake of this leading phalanx by small, capsized and dismembered tabular icebergs; (4) Extremely large gravitational potential energy release rates, e.g., up to 3 × 1010 W; (5) Lack of proximal iceberg-calving triggers that control the timing of break-up onset and that maintain the high break-up calving rates through to the conclusion of the event. Motivated by seismic records obtained from icebergs and the Ross Ice Shelf that show hundreds of micro- tsunamis emanating from near the ice shelf front, we re-examine the basic dynamic features of ice- shelf/ocean-wave interaction and, in particular, examine the possibility that collapsing ice shelves themselves are a source of waves that stimulate the disintegration process. We propose that ice-shelf generated surface-gravity waves associated with initial calving at an arbitrary seed location produce stress perturbations capable of triggering the onset of calving on the entire ice front. Waves generated by parting detachment rifts, iceberg capsize and break-up act next to stimulate an inverted submarine landslide (ice- slide) process, where gravitational potential energy released by upward movement of buoyant ice is radiated as surface gravity waves in the wake of the advancing phalanx of tabular icebergs. We conclude by describing how field research and remote sensing can be used to test the

  9. Parameterizing Size Distribution in Ice Clouds

    Energy Technology Data Exchange (ETDEWEB)

    DeSlover, Daniel; Mitchell, David L.

    2009-09-25

    PARAMETERIZING SIZE DISTRIBUTIONS IN ICE CLOUDS David L. Mitchell and Daniel H. DeSlover ABSTRACT An outstanding problem that contributes considerable uncertainty to Global Climate Model (GCM) predictions of future climate is the characterization of ice particle sizes in cirrus clouds. Recent parameterizations of ice cloud effective diameter differ by a factor of three, which, for overcast conditions, often translate to changes in outgoing longwave radiation (OLR) of 55 W m-2 or more. Much of this uncertainty in cirrus particle sizes is related to the problem of ice particle shattering during in situ sampling of the ice particle size distribution (PSD). Ice particles often shatter into many smaller ice fragments upon collision with the rim of the probe inlet tube. These small ice artifacts are counted as real ice crystals, resulting in anomalously high concentrations of small ice crystals (D < 100 µm) and underestimates of the mean and effective size of the PSD. Half of the cirrus cloud optical depth calculated from these in situ measurements can be due to this shattering phenomenon. Another challenge is the determination of ice and liquid water amounts in mixed phase clouds. Mixed phase clouds in the Arctic contain mostly liquid water, and the presence of ice is important for determining their lifecycle. Colder high clouds between -20 and -36 oC may also be mixed phase but in this case their condensate is mostly ice with low levels of liquid water. Rather than affecting their lifecycle, the presence of liquid dramatically affects the cloud optical properties, which affects cloud-climate feedback processes in GCMs. This project has made advancements in solving both of these problems. Regarding the first problem, PSD in ice clouds are uncertain due to the inability to reliably measure the concentrations of the smallest crystals (D < 100 µm), known as the “small mode”. Rather than using in situ probe measurements aboard aircraft, we employed a treatment of ice

  10. Headpond ice jams - where will they occur?

    Energy Technology Data Exchange (ETDEWEB)

    Judge, D.G.; Lavender, S.T. [Acres International Ltd., Niagara Falls, ON (Canada); Carson, R.W. [Acres International Ltd., Winnipeg, MB (Canada); Ismail, S. [New Brunswick Power, Fredericton, NB (Canada)

    1997-12-31

    A river ice simulation model used to analyze the many problems associated with ice during the construction of hydroelectric power plants was described. The model JAMSIM is a one-dimensional quasi-steady state analytical model that was developed to help river engineers in predicting locations along river channels where released ice jams are most likely to re-lodge. The model is used to calculate the stable cross-sectional ice area of a broken ice melee at each river section using the force balance considerations. JAMSIM is a modified version of an earlier model, the ICESIM. The concepts, structure capabilities and limitations of the ICESIM and the JAMSIM models were discussed. The models are useful for planning pipeline crossings, bridge crossings and other infrastructure projects. 3 refs., 6 figs.

  11. Cosmic Ray Studies with IceCube

    Science.gov (United States)

    Gonzalez, Javier

    In this contribution we will give an overview of the cosmic ray studies conducted within the IceCube collaboration. The IceCube detector in the geographical south pole can be used to measure various characteristics of the extensive air showers induced by high energy cosmic rays. With IceTop, the surface component of the detector, we detect the electromagnetic and muon components of the air showers, while with the deep detector we detect the high energy muons. We have measured the energy spectrum of cosmic ray primaries in the range between 1.58PeV and 1.26 EeV. A combined analysis of the high energy muon bundles in the ice and the air shower footprint in IceTop provides a measure of primary composition. We will also discuss how the sensitivity to low energy muons in the air showers has the potential to produce additional measures of primary composition.

  12. Continuous greenhouse gas measurements from ice cores

    DEFF Research Database (Denmark)

    Stowasser, Christopher

    Ice cores offer the unique possibility to study the history of past atmospheric greenhouse gases over the last 800,000 years, since past atmospheric air is trapped in bubbles in the ice. Since the 1950s, paleo-scientists have developed a variety of techniques to extract the trapped air from...... individual ice core samples, and to measure the mixing ratio of greenhouse gases such as carbon dioxide, methane and nitrous oxide in the extracted air. The discrete measurements have become highly accurate and reproducible, but require relatively large amounts of ice per measured species and are both time......-consuming and labor-intensive. This PhD thesis presents the development of a new method for measurements of greenhouse gas mixing ratios from ice cores based on a melting device of a continuous flow analysis (CFA) system. The coupling to a CFA melting device enables time-efficient measurements of high resolution...

  13. Disordered kagomé spin ice

    Science.gov (United States)

    Greenberg, Noah; Kunz, Andrew

    2018-05-01

    Artificial spin ice is made from a large array of patterned magnetic nanoislands designed to mimic naturally occurring spin ice materials. The geometrical arrangement of the kagomé lattice guarantees a frustrated arrangement of the islands' magnetic moments at each vertex where the three magnetic nanoislands meet. This frustration leads to a highly degenerate ground state which gives rise to a finite (residual) entropy at zero temperature. In this work we use the Monte Carlo simulation to explore the effects of disorder in kagomé spin ice. Disorder is introduced to the system by randomly removing a known percentage of magnetic islands from the lattice. The behavior of the spin ice changes as the disorder increases; evident by changes to the shape and locations of the peaks in heat capacity and the residual entropy. The results are consistent with observations made in diluted physical spin ice materials.

  14. The Science of Solar System Ices

    CERN Document Server

    Castillo-Rogez, Julie

    2013-01-01

    The Science of Solar System Ices The role of laboratory research and simulations in advancing our understanding of solar system ices (including satellites, KBOs, comets, and giant planets) is becoming increasingly important. Understanding ice surface radiation processing, particle and radiation penetration depths, surface and subsurface chemistry, morphology, phases, density, conductivity, etc., are only a few examples of the inventory of issues that are being addressed by Earth-based laboratory research. As a response to the growing need for cross-disciplinary dialog and communication in the planetary ices science community, this book aims to foster focused collaborations among the observational, modeling, and laboratory research communities. The book is a compilation of articles from experts in ices: experimentalists, modelers, and observers (ground-based telescopes and space missions). Most of the contributors featured in this book are renowned experts in their respective fields. Many of these scientists h...

  15. The effects of additional black carbon on Arctic sea ice surface albedo: variation with sea ice type and snow cover

    OpenAIRE

    A. A. Marks; M. D. King

    2013-01-01

    Black carbon in sea ice will decrease sea ice surface albedo through increased absorption of incident solar radiation, exacerbating sea ice melting. Previous literature has reported different albedo responses to additions of black carbon in sea ice and has not considered how a snow cover may mitigate the effect of black carbon in sea ice. Sea ice is predominately snow covered. Visible light absorption and light scattering coefficients are calculated for a typical first year and multi-y...

  16. Influence of ice thickness and surface properties on light transmission through Arctic sea ice.

    Science.gov (United States)

    Katlein, Christian; Arndt, Stefanie; Nicolaus, Marcel; Perovich, Donald K; Jakuba, Michael V; Suman, Stefano; Elliott, Stephen; Whitcomb, Louis L; McFarland, Christopher J; Gerdes, Rüdiger; Boetius, Antje; German, Christopher R

    2015-09-01

    The observed changes in physical properties of sea ice such as decreased thickness and increased melt pond cover severely impact the energy budget of Arctic sea ice. Increased light transmission leads to increased deposition of solar energy in the upper ocean and thus plays a crucial role for amount and timing of sea-ice-melt and under-ice primary production. Recent developments in underwater technology provide new opportunities to study light transmission below the largely inaccessible underside of sea ice. We measured spectral under-ice radiance and irradiance using the new Nereid Under-Ice (NUI) underwater robotic vehicle, during a cruise of the R/V Polarstern to 83°N 6°W in the Arctic Ocean in July 2014. NUI is a next generation hybrid remotely operated vehicle (H-ROV) designed for both remotely piloted and autonomous surveys underneath land-fast and moving sea ice. Here we present results from one of the first comprehensive scientific dives of NUI employing its interdisciplinary sensor suite. We combine under-ice optical measurements with three dimensional under-ice topography (multibeam sonar) and aerial images of the surface conditions. We investigate the influence of spatially varying ice-thickness and surface properties on the spatial variability of light transmittance during summer. Our results show that surface properties such as melt ponds dominate the spatial distribution of the under-ice light field on small scales (sea ice-thickness is the most important predictor for light transmission on larger scales. In addition, we propose the use of an algorithm to obtain histograms of light transmission from distributions of sea ice thickness and surface albedo.

  17. Contrasts in Sea Ice Formation and Production in the Arctic Seasonal and Perennial Ice Zones

    Science.gov (United States)

    Kwok, R.

    2006-01-01

    Four years (1997-2000) of RADARSAT Geophysical Processor System (RGPS) data are used to contrast the sea ice deformation and production regionally, and in the seasonal (SIZ) and perennial (PIZ) ice zones. Ice production is of seasonal ice in openings during the winter. 3-day estimates of these quantities are provided within Lagrangian elements initially 10 km on a side. A distinct seasonal cycle is seen in both zones with these estimates highest in the late fall and with seasonal minimums in the mid-winter. Regional divergence over the winter could be up to 30%. Spatially, the highest deformation is in the SIZ north of coastal Alaska. Both ice deformation and production are higher in the SIZ: deformation-related ice production in the SIZ (approx.0.5 m) is 1.5-2.3 times that of the PIZ (approx.0.3 m) - this is connected to ice strength and thickness. Atmospheric forcing and boundary layer structure contribute to only the seasonal and interannual variability. Seasonal ice growth in ice fractures accounts for approx.25-40% of the total ice production of the Arctic Ocean. By itself, this deformation-ice production relationship could be considered a negative feedback when thickness is perturbed. However, the overall effect on ice production in the face of increasing seasonal and thinner/weaker ice coverage could be modified by: local destabilization of the water column promoting overturning of warmer water due to increased brine rejection; and, the upwelling of the pynocline associated with increased occurrence of large shear motion in sea ice.

  18. Ross Sea Polynyas: Response of Ice Concentration Retrievals to Large Areas of Thin Ice

    Science.gov (United States)

    Kwok, R.; Comiso, J. C.; Martin, S.; Drucker, R.

    2007-01-01

    For a 3-month period between May and July of 2005, we examine the response of the Advanced Microwave Scanning Radiometer (AMSR-E) Enhanced NASA Team 2 (NT2) and AMSR-E Bootstrap (ABA) ice concentration algorithms to large areas of thin ice of the Ross Sea polynyas. Coincident Envisat Synthetic Aperture Radar (SAR) coverage of the region during this period offers a detailed look at the development of the polynyas within several hundred kilometers of the ice front. The high-resolution imagery and derived ice motion fields show bands of polynya ice, covering up to approximately 105 km(sup 2) of the Ross Sea, that are associated with wind-forced advection. In this study, ice thickness from AMSR-E 36 GHz polarization information serves as the basis for examination of the response. The quality of the thickness of newly formed sea ice (<10 cm) from AMSR-E is first assessed with thickness estimates derived from ice surface temperatures from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. The effect of large areas of thin ice in lowering the ice concentration estimates from both NT2/ABA approaches is clearly demonstrated. Results show relatively robust relationships between retrieved ice concentrations and thin ice thickness estimates that differ between the two algorithms. These relationships define the approximate spatial coincidence of ice concentration and thickness isopleths. Using the 83% (ABA) and 91% (NT2) isopleths as polynya boundaries, we show that the computed coverage compares well with that using the estimated 10-cm thickness contour. The thin ice response characterized here suggests that in regions with polynyas, the retrieval results could be used to provide useful geophysical information, namely thickness and coverage.

  19. Wave–ice interactions in the neXtSIM sea-ice model

    Directory of Open Access Journals (Sweden)

    T. D. Williams

    2017-09-01

    Full Text Available In this paper we describe a waves-in-ice model (WIM, which calculates ice breakage and the wave radiation stress (WRS. This WIM is then coupled to the new sea-ice model neXtSIM, which is based on the elasto-brittle (EB rheology. We highlight some numerical issues involved in the coupling and investigate the impact of the WRS, and of modifying the EB rheology to lower the stiffness of the ice in the area where the ice has broken up (the marginal ice zone or MIZ. In experiments in the absence of wind, we find that wind waves can produce noticeable movement of the ice edge in loose ice (concentration around 70 % – up to 36 km, depending on the material parameters of the ice that are used and the dynamical model used for the broken ice. The ice edge position is unaffected by the WRS if the initial concentration is higher (≳ 0.9. Swell waves (monochromatic waves with low frequency do not affect the ice edge location (even for loose ice, as they are attenuated much less than the higher-frequency components of a wind wave spectrum, and so consequently produce a much lower WRS (by about an order of magnitude at least.In the presence of wind, we find that the wind stress dominates the WRS, which, while large near the ice edge, decays exponentially away from it. This is in contrast to the wind stress, which is applied over a much larger ice area. In this case (when wind is present the dynamical model for the MIZ has more impact than the WRS, although that effect too is relatively modest. When the stiffness in the MIZ is lowered due to ice breakage, we find that on-ice winds produce more compression in the MIZ than in the pack, while off-ice winds can cause the MIZ to be separated from the pack ice.

  20. Sea ice biogeochemistry: a guide for modellers.

    Directory of Open Access Journals (Sweden)

    Letizia Tedesco

    Full Text Available Sea ice is a fundamental component of the climate system and plays a key role in polar trophic food webs. Nonetheless sea ice biogeochemical dynamics at large temporal and spatial scales are still rarely described. Numerical models may potentially contribute integrating among sparse observations, but available models of sea ice biogeochemistry are still scarce, whether their relevance for properly describing the current and future state of the polar oceans has been recently addressed. A general methodology to develop a sea ice biogeochemical model is presented, deriving it from an existing validated model application by extension of generic pelagic biogeochemistry model parameterizations. The described methodology is flexible and considers different levels of ecosystem complexity and vertical representation, while adopting a strategy of coupling that ensures mass conservation. We show how to apply this methodology step by step by building an intermediate complexity model from a published realistic application and applying it to analyze theoretically a typical season of first-year sea ice in the Arctic, the one currently needing the most urgent understanding. The aim is to (1 introduce sea ice biogeochemistry and address its relevance to ocean modelers of polar regions, supporting them in adding a new sea ice component to their modelling framework for a more adequate representation of the sea ice-covered ocean ecosystem as a whole, and (2 extend our knowledge on the relevant controlling factors of sea ice algal production, showing that beyond the light and nutrient availability, the duration of the sea ice season may play a key-role shaping the algal production during the on going and upcoming projected changes.

  1. The Sea-Ice Floe Size Distribution

    Science.gov (United States)

    Stern, H. L., III; Schweiger, A. J. B.; Zhang, J.; Steele, M.

    2017-12-01

    The size distribution of ice floes in the polar seas affects the dynamics and thermodynamics of the ice cover and its interaction with the ocean and atmosphere. Ice-ocean models are now beginning to include the floe size distribution (FSD) in their simulations. In order to characterize seasonal changes of the FSD and provide validation data for our ice-ocean model, we calculated the FSD in the Beaufort and Chukchi seas over two spring-summer-fall seasons (2013 and 2014) using more than 250 cloud-free visible-band scenes from the MODIS sensors on NASA's Terra and Aqua satellites, identifying nearly 250,000 ice floes between 2 and 30 km in diameter. We found that the FSD follows a power-law distribution at all locations, with a seasonally varying exponent that reflects floe break-up in spring, loss of smaller floes in summer, and the return of larger floes after fall freeze-up. We extended the results to floe sizes from 10 m to 2 km at selected time/space locations using more than 50 high-resolution radar and visible-band satellite images. Our analysis used more data and applied greater statistical rigor than any previous study of the FSD. The incorporation of the FSD into our ice-ocean model resulted in reduced sea-ice thickness, mainly in the marginal ice zone, which improved the simulation of sea-ice extent and yielded an earlier ice retreat. We also examined results from 17 previous studies of the FSD, most of which report power-law FSDs but with widely varying exponents. It is difficult to reconcile the range of results due to different study areas, seasons, and methods of analysis. We review the power-law representation of the FSD in these studies and discuss some mathematical details that are important to consider in any future analysis.

  2. Modern shelf ice, equatorial Aeolis Quadrangle, Mars

    Science.gov (United States)

    Brakenridge, G. R.

    1993-01-01

    As part of a detailed study of the geological and geomorphological evolution of Aeolis Quadrangle, I have encountered evidence suggesting that near surface ice exists at low latitudes and was formed by partial or complete freezing of an inland sea. The area of interest is centered at approximately -2 deg, 196 deg. As seen in a suite of Viking Orbiter frames obtained at a range of approximately 600 km, the plains surface at this location is very lightly cratered or uncratered, and it is thus of late Amazonian age. Extant topographic data indicate that the Amazonian plains at this location occupy a trough whose surface lies at least 1000 m below the Mars datum. A reasonable hypothesis is that quite recent surface water releases, perhaps associated with final evolution of large 'outflow chasms' to the south, but possibly from other source areas, filled this trough, that ice floes formed almost immediately, and that either grounded ice or an ice-covered sea still persists. A reasonable hypothesis is that quite recent surface water releases, perhaps associated with final evolution of large 'outflow chasms' to the south, but possibly from other source areas, filled this trough, that ice floes formed almost immediately, and that either grounded ice or an ice-covered sea still persists. In either case, the thin (a few meters at most) high albedo, low thermal inertia cover of aeolian materials was instrumental in allowing ice preservation, and at least the lower portions of this dust cover may be cemented by water ice. Detailed mapping using Viking stereopairs and quantitative comparisons to terrestrial shelf ice geometries are underway.

  3. High density amorphous ice and its phase transition to ice XII

    International Nuclear Information System (INIS)

    Kohl, I.

    2001-07-01

    1998 Lobban et al. reported the neutron diffraction data of a new phase of ice, called ice XII, which formed at 260 K on compression of water within the domain of ice V at a pressure of 0.5 GPa. Surprisingly ice XII forms as an incidental product in the preparation of high-density amorphous ice (HDA) on compression of hexagonale ice (ice Ih) at 77 K up to pressures = 1.3 GPa. A decisive experimental detail is the use of an indium container: when compressing ice Ih in a pressure vessel with indium linings, then reproducibly HDA (high density amorphous ice) forms, but without indium randomly scattered relative amounts of ice XII and HDA form. Ice XII forms on compression of ice Ih at 77 K only via HDA, and not directly from ice Ih. Its formation requires a sudden pronounced apparent pressure drop of ca 0.18 GPa at pressures ca 1.1 GPa. These apparent pressure drops can be caused by buildup friction between the piston and the pressure vessel and its sudden release on further compression. I propose that shock-waves generated by apparent pressure drops cause transient local heating and that this induces nucleation and crystal growth. A specific reproducible method to prepare ice XII is heating HDA in a pressure vessel with indium linings at constant pressures (or constant volume). The ice XII (meta-)stability domain extends between ca 158 and 212 K from ca 0.7 to ca 1.5 GPa. DSC (differential scanning calorimetry) and x-ray powder diffraction revealed, that on heating at atmospheric pressure ice XII transforms directly into cubic ice (ice Ic) at 154 K (heating rate 10 K min - 1) and not into an amorphous form before transition to ice Ic. The enthalpy of the ice XII - ice Ic transition is -1.21 ± 0.07 kJ mol -1 . An estimation of the Gibbs free energy at atmospheric pressure and about 140 K results that ice XII is thermodynamically more stable than ice VI. In the heating curve of ice XII a reversible endothermic step can be found at the onset temperature (heating rate

  4. The Response of Ice Sheets to Climate Variability

    Science.gov (United States)

    Snow, K.; Goldberg, D. N.; Holland, P. R.; Jordan, J. R.; Arthern, R. J.; Jenkins, A.

    2017-12-01

    West Antarctic Ice Sheet loss is a significant contributor to sea level rise. While the ice loss is thought to be triggered by fluctuations in oceanic heat at the ice shelf bases, ice sheet response to ocean variability remains poorly understood. Using a synchronously coupled ice-ocean model permitting grounding line migration, this study evaluates the response of an ice sheet to periodic variations in ocean forcing. Resulting oscillations in grounded ice volume amplitude is shown to grow as a nonlinear function of ocean forcing period. This implies that slower oscillations in climatic forcing are disproportionately important to ice sheets. The ice shelf residence time offers a critical time scale, above which the ice response amplitude is a linear function of ocean forcing period and below which it is quadratic. These results highlight the sensitivity of West Antarctic ice streams to perturbations in heat fluxes occurring at decadal time scales.

  5. Fundamental Ice Crystal Accretion Physics Studies

    Science.gov (United States)

    Struk, Peter M.; Broeren, Andy P.; Tsao, Jen-Ching; Vargas, Mario; Wright, William B.; Currie, Tom; Knezevici, Danny; Fuleki, Dan

    2012-01-01

    Due to numerous engine power-loss events associated with high-altitude convective weather, ice accretion within an engine due to ice crystal ingestion is being investigated. The National Aeronautics and Space Administration (NASA) and the National Research Council (NRC) of Canada are starting to examine the physical mechanisms of ice accretion on surfaces exposed to ice-crystal and mixed-phase conditions. In November 2010, two weeks of testing occurred at the NRC Research Altitude Facility utilizing a single wedge-type airfoil designed to facilitate fundamental studies while retaining critical features of a compressor stator blade or guide vane. The airfoil was placed in the NRC cascade wind tunnel for both aerodynamic and icing tests. Aerodynamic testing showed excellent agreement compared with CFD data on the icing pressure surface and allowed calculation of heat transfer coefficients at various airfoil locations. Icing tests were performed at Mach numbers of 0.2 to 0.3, total pressures from 93 to 45 kPa, and total temperatures from 5 to 15 C. Ice and liquid water contents ranged up to 20 and 3 g/m3, respectively. The ice appeared well adhered to the surface in the lowest pressure tests (45 kPa) and, in a particular case, showed continuous leading-edge ice growth to a thickness greater than 15 mm in 3 min. Such widespread deposits were not observed in the highest pressure tests, where the accretions were limited to a small area around the leading edge. The suction surface was typically ice-free in the tests at high pressure, but not at low pressure. The icing behavior at high and low pressure appeared to be correlated with the wet-bulb temperature, which was estimated to be above 0 C in tests at 93 kPa and below 0 C in tests at lower pressure, the latter enhanced by more evaporative cooling of water. The authors believe that the large ice accretions observed in the low pressure tests would undoubtedly cause the aerodynamic performance of a compressor component

  6. Changes in ice dynamics and mass balance of the Antarctic ice sheet.

    Science.gov (United States)

    Rignot, Eric

    2006-07-15

    The concept that the Antarctic ice sheet changes with eternal slowness has been challenged by recent observations from satellites. Pronounced regional warming in the Antarctic Peninsula triggered ice shelf collapse, which led to a 10-fold increase in glacier flow and rapid ice sheet retreat. This chain of events illustrated the vulnerability of ice shelves to climate warming and their buffering role on the mass balance of Antarctica. In West Antarctica, the Pine Island Bay sector is draining far more ice into the ocean than is stored upstream from snow accumulation. This sector could raise sea level by 1m and trigger widespread retreat of ice in West Antarctica. Pine Island Glacier accelerated 38% since 1975, and most of the speed up took place over the last decade. Its neighbour Thwaites Glacier is widening up and may double its width when its weakened eastern ice shelf breaks up. Widespread acceleration in this sector may be caused by glacier ungrounding from ice shelf melting by an ocean that has recently warmed by 0.3 degrees C. In contrast, glaciers buffered from oceanic change by large ice shelves have only small contributions to sea level. In East Antarctica, many glaciers are close to a state of mass balance, but sectors grounded well below sea level, such as Cook Ice Shelf, Ninnis/Mertz, Frost and Totten glaciers, are thinning and losing mass. Hence, East Antarctica is not immune to changes.

  7. IceMap250—Automatic 250 m Sea Ice Extent Mapping Using MODIS Data

    Directory of Open Access Journals (Sweden)

    Charles Gignac

    2017-01-01

    Full Text Available The sea ice cover in the North evolves at a rapid rate. To adequately monitor this evolution, tools with high temporal and spatial resolution are needed. This paper presents IceMap250, an automatic sea ice extent mapping algorithm using MODIS reflective/emissive bands. Hybrid cloud-masking using both the MOD35 mask and a visibility mask, combined with downscaling of Bands 3–7 to 250 m, are utilized to delineate sea ice extent using a decision tree approach. IceMap250 was tested on scenes from the freeze-up, stable cover, and melt seasons in the Hudson Bay complex, in Northeastern Canada. IceMap250 first product is a daily composite sea ice presence map at 250 m. Validation based on comparisons with photo-interpreted ground-truth show the ability of the algorithm to achieve high classification accuracy, with kappa values systematically over 90%. IceMap250 second product is a weekly clear sky map that provides a synthesis of 7 days of daily composite maps. This map, produced using a majority filter, makes the sea ice presence map even more accurate by filtering out the effects of isolated classification errors. The synthesis maps show spatial consistency through time when compared to passive microwave and national ice services maps.

  8. Tidal Modulation of Ice-shelf Flow: a Viscous Model of the Ross Ice Shelf

    Science.gov (United States)

    Brunt, Kelly M.; MacAyeal, Douglas R.

    2014-01-01

    Three stations near the calving front of the Ross Ice Shelf, Antarctica, recorded GPS data through a full spring-neap tidal cycle in November 2005. The data revealed a diurnal horizontal motion that varied both along and transverse to the long-term average velocity direction, similar to tidal signals observed in other ice shelves and ice streams. Based on its periodicity, it was hypothesized that the signal represents a flow response of the Ross Ice Shelf to the diurnal tides of the Ross Sea. To assess the influence of the tide on the ice-shelf motion, two hypotheses were developed. The first addressed the direct response of the ice shelf to tidal forcing, such as forces due to sea-surface slopes or forces due to sub-ice-shelf currents. The second involved the indirect response of ice-shelf flow to the tidal signals observed in the ice streams that source the ice shelf. A finite-element model, based on viscous creep flow, was developed to test these hypotheses, but succeeded only in falsifying both hypotheses, i.e. showing that direct tidal effects produce too small a response, and indirect tidal effects produce a response that is not smooth in time. This nullification suggests that a combination of viscous and elastic deformation is required to explain the observations.

  9. Ice nucleation active bacteria in precipitation are genetically diverse and nucleate ice by employing different mechanisms.

    Science.gov (United States)

    Failor, K C; Schmale, D G; Vinatzer, B A; Monteil, C L

    2017-12-01

    A growing body of circumstantial evidence suggests that ice nucleation active (Ice + ) bacteria contribute to the initiation of precipitation by heterologous freezing of super-cooled water in clouds. However, little is known about the concentration of Ice + bacteria in precipitation, their genetic and phenotypic diversity, and their relationship to air mass trajectories and precipitation chemistry. In this study, 23 precipitation events were collected over 15 months in Virginia, USA. Air mass trajectories and water chemistry were determined and 33 134 isolates were screened for ice nucleation activity (INA) at -8 °C. Of 1144 isolates that tested positive during initial screening, 593 had confirmed INA at -8 °C in repeated tests. Concentrations of Ice + strains in precipitation were found to range from 0 to 13 219 colony forming units per liter, with a mean of 384±147. Most Ice + bacteria were identified as members of known and unknown Ice + species in the Pseudomonadaceae, Enterobacteriaceae and Xanthomonadaceae families, which nucleate ice employing the well-characterized membrane-bound INA protein. Two Ice + strains, however, were identified as Lysinibacillus, a Gram-positive genus not previously known to include Ice + bacteria. INA of the Lysinibacillus strains is due to a nanometer-sized molecule that is heat resistant, lysozyme and proteinase resistant, and secreted. Ice + bacteria and the INA mechanisms they employ are thus more diverse than expected. We discuss to what extent the concentration of culturable Ice + bacteria in precipitation and the identification of a new heat-resistant biological INA mechanism support a role for Ice + bacteria in the initiation of precipitation.

  10. Capabilities and performance of Elmer/Ice, a new-generation ice sheet model

    Directory of Open Access Journals (Sweden)

    O. Gagliardini

    2013-08-01

    Full Text Available The Fourth IPCC Assessment Report concluded that ice sheet flow models, in their current state, were unable to provide accurate forecast for the increase of polar ice sheet discharge and the associated contribution to sea level rise. Since then, the glaciological community has undertaken a huge effort to develop and improve a new generation of ice flow models, and as a result a significant number of new ice sheet models have emerged. Among them is the parallel finite-element model Elmer/Ice, based on the open-source multi-physics code Elmer. It was one of the first full-Stokes models used to make projections for the evolution of the whole Greenland ice sheet for the coming two centuries. Originally developed to solve local ice flow problems of high mechanical and physical complexity, Elmer/Ice has today reached the maturity to solve larger-scale problems, earning the status of an ice sheet model. Here, we summarise almost 10 yr of development performed by different groups. Elmer/Ice solves the full-Stokes equations, for isotropic but also anisotropic ice rheology, resolves the grounding line dynamics as a contact problem, and contains various basal friction laws. Derived fields, like the age of the ice, the strain rate or stress, can also be computed. Elmer/Ice includes two recently proposed inverse methods to infer badly known parameters. Elmer is a highly parallelised code thanks to recent developments and the implementation of a block preconditioned solver for the Stokes system. In this paper, all these components are presented in detail, as well as the numerical performance of the Stokes solver and developments planned for the future.

  11. New Tools for Sea Ice Data Analysis and Visualization: NSIDC's Arctic Sea Ice News and Analysis

    Science.gov (United States)

    Vizcarra, N.; Stroeve, J.; Beam, K.; Beitler, J.; Brandt, M.; Kovarik, J.; Savoie, M. H.; Skaug, M.; Stafford, T.

    2017-12-01

    Arctic sea ice has long been recognized as a sensitive climate indicator and has undergone a dramatic decline over the past thirty years. Antarctic sea ice continues to be an intriguing and active field of research. The National Snow and Ice Data Center's Arctic Sea Ice News & Analysis (ASINA) offers researchers and the public a transparent view of sea ice data and analysis. We have released a new set of tools for sea ice analysis and visualization. In addition to Charctic, our interactive sea ice extent graph, the new Sea Ice Data and Analysis Tools page provides access to Arctic and Antarctic sea ice data organized in seven different data workbooks, updated daily or monthly. An interactive tool lets scientists, or the public, quickly compare changes in ice extent and location. Another tool allows users to map trends, anomalies, and means for user-defined time periods. Animations of September Arctic and Antarctic monthly average sea ice extent and concentration may also be accessed from this page. Our tools help the NSIDC scientists monitor and understand sea ice conditions in near real time. They also allow the public to easily interact with and explore sea ice data. Technical innovations in our data center helped NSIDC quickly build these tools and more easily maintain them. The tools were made publicly accessible to meet the desire from the public and members of the media to access the numbers and calculations that power our visualizations and analysis. This poster explores these tools and how other researchers, the media, and the general public are using them.

  12. Reconciling records of ice streaming and ice margin retreat to produce a palaeogeographic reconstruction of the deglaciation of the Laurentide Ice Sheet

    Science.gov (United States)

    Margold, Martin; Stokes, Chris R.; Clark, Chris D.

    2018-06-01

    This paper reconstructs the deglaciation of the Laurentide Ice Sheet (LIS; including the Innuitian Ice Sheet) from the Last Glacial Maximum (LGM), with a particular focus on the spatial and temporal variations in ice streaming and the associated changes in flow patterns and ice divides. We build on a recent inventory of Laurentide ice streams and use an existing ice margin chronology to produce the first detailed transient reconstruction of the ice stream drainage network in the LIS, which we depict in a series of palaeogeographic maps. Results show that the drainage network at the LGM was similar to modern-day Antarctica. The majority of the ice streams were marine terminating and topographically-controlled and many of these continued to function late into the deglaciation, until the ice sheet lost its marine margin. Ice streams with a terrestrial ice margin in the west and south were more transient and ice flow directions changed with the build-up, peak-phase and collapse of the Cordilleran-Laurentide ice saddle. The south-eastern marine margin in Atlantic Canada started to retreat relatively early and some of the ice streams in this region switched off at or shortly after the LGM. In contrast, the ice streams draining towards the north-western and north-eastern marine margins in the Beaufort Sea and in Baffin Bay appear to have remained stable throughout most of the Late Glacial, and some of them continued to function until after the Younger Dryas (YD). The YD influenced the dynamics of the deglaciation, but there remains uncertainty about the response of the ice sheet in several sectors. We tentatively ascribe the switching-on of some major ice streams during this period (e.g. M'Clintock Channel Ice Stream at the north-west margin), but for other large ice streams whose timing partially overlaps with the YD, the drivers are less clear and ice-dynamical processes, rather than effects of climate and surface mass balance are viewed as more likely drivers. Retreat

  13. Impact of aerosols on ice crystal size

    Science.gov (United States)

    Zhao, Bin; Liou, Kuo-Nan; Gu, Yu; Jiang, Jonathan H.; Li, Qinbin; Fu, Rong; Huang, Lei; Liu, Xiaohong; Shi, Xiangjun; Su, Hui; He, Cenlin

    2018-01-01

    The interactions between aerosols and ice clouds represent one of the largest uncertainties in global radiative forcing from pre-industrial time to the present. In particular, the impact of aerosols on ice crystal effective radius (Rei), which is a key parameter determining ice clouds' net radiative effect, is highly uncertain due to limited and conflicting observational evidence. Here we investigate the effects of aerosols on Rei under different meteorological conditions using 9-year satellite observations. We find that the responses of Rei to aerosol loadings are modulated by water vapor amount in conjunction with several other meteorological parameters. While there is a significant negative correlation between Rei and aerosol loading in moist conditions, consistent with the "Twomey effect" for liquid clouds, a strong positive correlation between the two occurs in dry conditions. Simulations based on a cloud parcel model suggest that water vapor modulates the relative importance of different ice nucleation modes, leading to the opposite aerosol impacts between moist and dry conditions. When ice clouds are decomposed into those generated from deep convection and formed in situ, the water vapor modulation remains in effect for both ice cloud types, although the sensitivities of Rei to aerosols differ noticeably between them due to distinct formation mechanisms. The water vapor modulation can largely explain the difference in the responses of Rei to aerosol loadings in various seasons. A proper representation of the water vapor modulation is essential for an accurate estimate of aerosol-cloud radiative forcing produced by ice clouds.

  14. Impact of aerosols on ice crystal size

    Directory of Open Access Journals (Sweden)

    B. Zhao

    2018-01-01

    Full Text Available The interactions between aerosols and ice clouds represent one of the largest uncertainties in global radiative forcing from pre-industrial time to the present. In particular, the impact of aerosols on ice crystal effective radius (Rei, which is a key parameter determining ice clouds' net radiative effect, is highly uncertain due to limited and conflicting observational evidence. Here we investigate the effects of aerosols on Rei under different meteorological conditions using 9-year satellite observations. We find that the responses of Rei to aerosol loadings are modulated by water vapor amount in conjunction with several other meteorological parameters. While there is a significant negative correlation between Rei and aerosol loading in moist conditions, consistent with the "Twomey effect" for liquid clouds, a strong positive correlation between the two occurs in dry conditions. Simulations based on a cloud parcel model suggest that water vapor modulates the relative importance of different ice nucleation modes, leading to the opposite aerosol impacts between moist and dry conditions. When ice clouds are decomposed into those generated from deep convection and formed in situ, the water vapor modulation remains in effect for both ice cloud types, although the sensitivities of Rei to aerosols differ noticeably between them due to distinct formation mechanisms. The water vapor modulation can largely explain the difference in the responses of Rei to aerosol loadings in various seasons. A proper representation of the water vapor modulation is essential for an accurate estimate of aerosol–cloud radiative forcing produced by ice clouds.

  15. Ice interactions at a dam face

    Energy Technology Data Exchange (ETDEWEB)

    Morse, B.; Morse, J.; Beaulieu, P.; Pratt, Y. [Laval Univ., Quebec City, PQ (Canada). Dept. of Civil Engineering; Stander, E. [State Univ. of New York, Cobleskill College, Cobleskill, NY (United States). Dept. of Natural Sciences; Cote, A.; Tarras, A.; Noel, P. [Hydro-Quebec, Varennes, PQ (Canada). IREQ

    2009-07-01

    This paper reported on a joint research project between Laval University and Hydro-Quebec to study ice forces on dams in an effort to harmonize design criteria and develop mitigation strategies. This paper introduced the project and explored some of the preliminary results of the 2007-2008 field season. Ice displacement, ice stresses and ice forces on the LaGabelle dam were measured at several locations. The paper identified and discussed the complex relationships between data sets and discussed the spatial-temporal variability of the ice forces and its impact on design criteria. The project objective was to develop design criteria for ice forces on dams and to provide a scientific basis for interpreting and harmonizing existing recommended criteria. The methodology and site description were presented. It was concluded that the ice processes in a reservoir near a dam face subject to water fluctuations are quite complex. Therefore, in order to know the real average pressure on the dam, a significant amount of panels are required, having important implications for determining safe design values. 9 refs., 10 figs.

  16. Snowball Earth: Skating on Thin Ice?

    Science.gov (United States)

    Roberson, A. L.; Stout, A. M.; Pollard, D.; Kasting, J. F.

    2011-12-01

    There is evidence of at least two intervals of widespread glaciation during the late Neoproterozoic (600-800 Myr ago), which are commonly referred to as "Snowball Earth" episodes. The global nature of these events is indicated by the fact that glacial deposits are found at low paleolatitudes during this time. Models of a global glacial event have produced a variety of solutions at low latitudes: thick ice, thin ice, slushball, and open ocean . The latter two models are similar, except that the slushball model has its ice-line at higher latitudes. To be viable, a model has to be able to account for the survival of life through the glaciations and also explain the existence of cap carbonates and other glacial debris deposited at low latitudes. The "thick-ice" model is not viable because kilometers of ice prevent the penetration of light necessary for the photosynthetic biota below. The "slushball" model is also not viable as it does not allow the formation of cap carbonates. The "thin-ice" model has been discussed previously and can account for continuation of photosynthetic life and glacial deposits at low paleolatitudes. The recently proposed "open-ocean" or "Jormungand" model also satisfies these requirements. What is it, though, that causes some models to produce thin ice near the equator and others to have open water there? We examine this question using a zonally symmetric energy balance climate model (EBM) with flowing sea glaciers to determine what parameter ranges produce each type of solution.

  17. Hydrogen-Bonding Surfaces for Ice Mitigation

    Science.gov (United States)

    Smith, Joseph G., Jr.; Wohl, Christopher J.; Kreeger, Richard E.; Hadley, Kevin R.; McDougall, Nicholas

    2014-01-01

    Ice formation on aircraft, either on the ground or in-flight, is a major safety issue. While ground icing events occur predominantly during the winter months, in-flight icing can happen anytime during the year. The latter is more problematic since it could result in increased drag and loss of lift. Under a Phase I ARMD NARI Seedling Activity, coated aluminum surfaces possessing hydrogen-bonding groups were under investigation for mitigating ice formation. Hydroxyl and methyl terminated dimethylethoxysilanes were prepared via known chemistries and characterized by spectroscopic methods. These materials were subsequently used to coat aluminum surfaces. Surface compositions were based on pure hydroxyl and methyl terminated species as well as mixtures of the two. Coated surfaces were characterized by contact angle goniometry. Receding water contact angle data suggested several potential surfaces that may exhibit reduced ice adhesion. Qualitative icing experiments performed under representative environmental temperatures using supercooled distilled water delivered via spray coating were inconclusive. Molecular modeling studies suggested that chain mobility affected the interface between ice and the surface more than terminal group chemical composition. Chain mobility resulted from the creation of "pockets" of increased free volume for longer chains to occupy.

  18. Initiation of secondary ice production in clouds

    Directory of Open Access Journals (Sweden)

    S. C. Sullivan

    2018-02-01

    Full Text Available Disparities between the measured concentrations of ice-nucleating particles (INPs and in-cloud ice crystal number concentrations (ICNCs have led to the hypothesis that mechanisms other than primary nucleation form ice in the atmosphere. Here, we model three of these secondary production mechanisms – rime splintering, frozen droplet shattering, and ice–ice collisional breakup – with a six-hydrometeor-class parcel model. We perform three sets of simulations to understand temporal evolution of ice hydrometeor number (Nice, thermodynamic limitations, and the impact of parametric uncertainty when secondary production is active. Output is assessed in terms of the number of primarily nucleated ice crystals that must exist before secondary production initiates (NINP(lim as well as the ICNC enhancement from secondary production and the timing of a 100-fold enhancement. Nice evolution can be understood in terms of collision-based nonlinearity and the phasedness of the process, i.e., whether it involves ice hydrometeors, liquid ones, or both. Ice–ice collisional breakup is the only process for which a meaningful NINP(lim exists (0.002 up to 0.15 L−1. For droplet shattering and rime splintering, a warm enough cloud base temperature and modest updraft are the more important criteria for initiation. The low values of NINP(lim here suggest that, under appropriate thermodynamic conditions for secondary ice production, perturbations in cloud concentration nuclei concentrations are more influential in mixed-phase partitioning than those in INP concentrations.

  19. Variational Ridging in Sea Ice Models

    Science.gov (United States)

    Roberts, A.; Hunke, E. C.; Lipscomb, W. H.; Maslowski, W.; Kamal, S.

    2017-12-01

    This work presents the results of a new development to make basin-scale sea ice models aware of the shape, porosity and extent of individual ridges within the pack. We have derived an analytic solution for the Euler-Lagrange equation of individual ridges that accounts for non-conservative forces, and therefore the compressive strength of individual ridges. Because a region of the pack is simply a collection of paths of individual ridges, we are able to solve the Euler-Lagrange equation for a large-scale sea ice field also, and therefore the compressive strength of a region of the pack that explicitly accounts for the macro-porosity of ridged debris. We make a number of assumptions that have simplified the problem, such as treating sea ice as a granular material in ridges, and assuming that bending moments associated with ridging are perturbations around an isostatic state. Regardless of these simplifications, the ridge model is remarkably predictive of macro-porosity and ridge shape, and, because our equations are analytic, they do not require costly computations to solve the Euler-Lagrange equation of ridges on the large scale. The new ridge model is therefore applicable to large-scale sea ice models. We present results from this theoretical development, as well as plans to apply it to the Regional Arctic System Model and a community sea ice code. Most importantly, the new ridging model is particularly useful for pinpointing gaps in our observational record of sea ice ridges, and points to the need for improved measurements of the evolution of porosity of deformed ice in the Arctic and Antarctic. Such knowledge is not only useful for improving models, but also for improving estimates of sea ice volume derived from altimetric measurements of sea ice freeboard.

  20. Ice ages and nuclear waste disposal

    International Nuclear Information System (INIS)

    Ahonen, L.; Ruskeeniemi, T.; Luukkonen, A.; Pitkaenen, P.; Rasilainen, K.

    2002-01-01

    This report is an overview of Quaternary Ice Age and its potential consequences for nuclear waste disposal. Geological information on past climatic changes is shortly reviewed, based on the following records: geomorphological information, loessic deposits, deep-sea carbonate sediments, ice-core records, and continental calcite precipitates. Even though the present 'Great Ice Age' has lasted more that two million years, the present variation in cycles of about 100 000 years seems to have commenced only about 600 - 700 thousands years ago. According to the present understanding, southern Finland was during a major span of Weichsel free of continental ice sheet. However, the conditions may have been very cold, periglacial, when the continental ice sheet covered the Caledonian mountains and large areas of central Fennoscandia. The last glacial maximum of Weichsel glaciation was shorter than estimated earlier. Periglacial conditions are characterized by deep permafrost, reaching even the depth of nuclear waste disposal. Calculations of the advancement of permafrost indicate that the permafrost-front may reach the depth of about 500 meters in less than 10 000 years. The crust beneath the continental ice cover depresses, and rebounds when the ice sheet retreats. During the most intensive vertical movement of the crust, some crush zones may be activated and bedrock movements may take place along them. Due to the growth of ice sheets, ocean water table also depresses during glacial maximum, thus changing hydrogeological conditions in non-glaciated terrains. Increase in global ice volume is manifested in the stable oxygen and hydrogen isotope ratios. Based on isotope signals, as well other hydrogeochemical interpretation methods, indications of the earlier glaciations have been recognized in present groundwaters. (orig.)

  1. Ice cloud processing of ultra-viscous/glassy aerosol particles leads to enhanced ice nucleation ability

    Directory of Open Access Journals (Sweden)

    R. Wagner

    2012-09-01

    Full Text Available The ice nucleation potential of airborne glassy aqueous aerosol particles has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 247 and 216 K. Four different solutes were used as proxies for oxygenated organic matter found in the atmosphere: raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA, levoglucosan, and a multi-component mixture of raffinose with five dicarboxylic acids and ammonium sulphate. Similar to previous experiments with citric acid aerosols, all particles were found to nucleate ice heterogeneously before reaching the homogeneous freezing threshold provided that the freezing cycles were started well below the respective glass transition temperatures of the compounds; this is discussed in detail in a separate article. In this contribution, we identify a further mechanism by which glassy aerosols can promote ice nucleation below the homogeneous freezing limit. If the glassy aerosol particles are probed in freezing cycles started only a few degrees below their respective glass transition temperatures, they enter the liquid regime of the state diagram upon increasing relative humidity (moisture-induced glass-to-liquid transition before being able to act as heterogeneous ice nuclei. Ice formation then only occurs by homogeneous freezing at elevated supersaturation levels. When ice forms the remaining solution freeze concentrates and re-vitrifies. If these ice cloud processed glassy aerosol particles are then probed in a second freezing cycle at the same temperature, they catalyse ice formation at a supersaturation threshold between 5 and 30% with respect to ice. By analogy with the enhanced ice nucleation ability of insoluble ice nuclei like mineral dusts after they nucleate ice once, we refer to this phenomenon as pre-activation. We propose a number of possible explanations for why glassy aerosol particles that have re

  2. Dark ice dynamics of the south-west Greenland Ice Sheet

    Science.gov (United States)

    Tedstone, Andrew J.; Bamber, Jonathan L.; Cook, Joseph M.; Williamson, Christopher J.; Fettweis, Xavier; Hodson, Andrew J.; Tranter, Martyn

    2017-11-01

    Runoff from the Greenland Ice Sheet (GrIS) has increased in recent years due largely to changes in atmospheric circulation and atmospheric warming. Albedo reductions resulting from these changes have amplified surface melting. Some of the largest declines in GrIS albedo have occurred in the ablation zone of the south-west sector and are associated with the development of dark ice surfaces. Field observations at local scales reveal that a variety of light-absorbing impurities (LAIs) can be present on the surface, ranging from inorganic particulates to cryoconite materials and ice algae. Meanwhile, satellite observations show that the areal extent of dark ice has varied significantly between recent successive melt seasons. However, the processes that drive such large interannual variability in dark ice extent remain essentially unconstrained. At present we are therefore unable to project how the albedo of bare ice sectors of the GrIS will evolve in the future, causing uncertainty in the projected sea level contribution from the GrIS over the coming decades. Here we use MODIS satellite imagery to examine dark ice dynamics on the south-west GrIS each year from 2000 to 2016. We quantify dark ice in terms of its annual extent, duration, intensity and timing of first appearance. Not only does dark ice extent vary significantly between years but so too does its duration (from 0 to > 80 % of June-July-August, JJA), intensity and the timing of its first appearance. Comparison of dark ice dynamics with potential meteorological drivers from the regional climate model MAR reveals that the JJA sensible heat flux, the number of positive minimum-air-temperature days and the timing of bare ice appearance are significant interannual synoptic controls. We use these findings to identify the surface processes which are most likely to explain recent dark ice dynamics. We suggest that whilst the spatial distribution of dark ice is best explained by outcropping of particulates from

  3. Balance Velocities of the Greenland Ice Sheet

    Science.gov (United States)

    Joughin, Ian; Fahnestock, Mark; Ekholm, Simon; Kwok, Ron

    1997-01-01

    We present a map of balance velocities for the Greenland ice sheet. The resolution of the underlying DEM, which was derived primarily from radar altimetry data, yields far greater detail than earlier balance velocity estimates for Greenland. The velocity contours reveal in striking detail the location of an ice stream in northeastern Greenland, which was only recently discovered using satellite imagery. Enhanced flow associated with all of the major outlets is clearly visible, although small errors in the source data result in less accurate estimates of the absolute flow speeds. Nevertheless, the balance map is useful for ice-sheet modelling, mass balance studies, and field planning.

  4. Arctic tides from GPS on sea ice

    OpenAIRE

    Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René

    2012-01-01

    The presence of sea-ice in the Arctic Ocean plays a significant role in the Arctic climate. Sea ice dampens the ocean tide amplitude with the result that global tidal models which use only astronomical data perform less accurately in the polar regions. This study presents a kinematic processing of Global Positioning System (GPS) buoys placed on sea-ice at five different sites north of Greenland for the study of sea level height and tidal analysis to improve tidal models in the Central Arctic....

  5. IceCube Results and PINGU Perspectives

    DEFF Research Database (Denmark)

    Koskinen, David Jason

    2015-01-01

    The last three years of IceCube operation with the completed detector have resulted in a plethora of results, including the first observation of high energy astrophysical neutrinos, tests of a possible neutrino flux from atmospheric charm meson decay, and competitive results of neutrino oscillation...... from atmospheric muon neutrino disappearance. Based on the success of IceCube, a new low energy in-fill, known as the Precision IceCube Next Generation Upgrade, is being proposed with the primary physics goal of resolving the ordering of the neutrino mass hierarchy....

  6. Structure of a new dense amorphous ice

    International Nuclear Information System (INIS)

    Finney, J.L.; Bowron, D.T.; Soper, A.K.; Loerting, T.; Mayer, E.; Hallbrucker, A.

    2002-01-01

    The detailed structure of a new dense amorphous ice, VHDA, is determined by isotope substitution neutron diffraction. Its structure is characterized by a doubled occupancy of the stabilizing interstitial location that was found in high density amorphous ice, HDA. As would be expected for a thermally activated unlocking of the stabilizing 'interstitial', the transition from VHDA to LDA (low-density amorphous ice) is very sharp. Although its higher density makes VHDA a better candidate than HDA for a physical manifestation of the second putative liquid phase of water, as for the HDA case, the VHDA to LDA transition also appears to be kinetically controlled

  7. Peculiarities of Vibration Characteristics of Amorphous Ices

    Science.gov (United States)

    Gets, Kirill V.; Subbotin, Oleg S.; Belosludov, Vladimir R.

    2012-03-01

    Dynamic properties of low (LDA), high (HDA) and very high (VHDA) density amorphous ices were investigated within the approach based on Lattice Dynamics simulations. In this approach, we assume that the short-range molecular order mainly determines the dynamic and thermodynamic properties of amorphous ices. Simulation cell of 512 water molecules with periodical boundary conditions and disordering allows us to study dynamical properties and dispersion curves in the Brillouin zone of pseudo-crystal. Existence of collective phenomena in amorphous ices which is usual for crystals but anomalous for disordered phase was confirmed in our simulations. Molecule amplitudes of delocalized (collective) as well as localized vibrations have been considered.

  8. Interaction of ice sheets and climate on geological time scales

    NARCIS (Netherlands)

    Stap, L.B.

    2017-01-01

    Since the inception of the Antarctic ice sheet at the Eocene-Oligocene Transition (~34 Myr ago), land ice plays a crucial role in Earth’s climate. Through the ice-albedo and surface-height-temperature feedbacks, land ice variability strengthens atmospheric temperature changes induced by orbital and

  9. An ice crystal model for jupiter's moon Europa

    DEFF Research Database (Denmark)

    Dahl-Jensen, Dorthe; schmidt, Karen Guldbae

    2003-01-01

    A simple model for crystal growth in the ice shell of Europa has been made in order to estimate the size of ice crystals at Europa's surface. If mass is lost from the surface of Europa due to sputtering processes, and the ice thickness is constant in time, ice crystals will be transported upwards...

  10. High resolution modelling of the decreasing Arctic sea ice

    DEFF Research Database (Denmark)

    Madsen, K. S.; Rasmussen, T. A. S.; Blüthgen, Jonas

    2012-01-01

    The Arctic sea ice cover has been rapidly decreasing and thinning over the last decade, with minimum ice extent in 2007 and almost as low extent in 2011. This study investigates two aspects of the decreasing ice cover; first the large scale thinning and changing dynamics of the polar sea ice, and...

  11. Optical properties of melting first-year Arctic sea ice

    Science.gov (United States)

    Light, Bonnie; Perovich, Donald K.; Webster, Melinda A.; Polashenski, Christopher; Dadic, Ruzica

    2015-11-01

    The albedo and transmittance of melting, first-year Arctic sea ice were measured during two cruises of the Impacts of Climate on the Eco-Systems and Chemistry of the Arctic Pacific Environment (ICESCAPE) project during the summers of 2010 and 2011. Spectral measurements were made for both bare and ponded ice types at a total of 19 ice stations in the Chukchi and Beaufort Seas. These data, along with irradiance profiles taken within boreholes, laboratory measurements of the optical properties of core samples, ice physical property observations, and radiative transfer model simulations are employed to describe representative optical properties for melting first-year Arctic sea ice. Ponded ice was found to transmit roughly 4.4 times more total energy into the ocean, relative to nearby bare ice. The ubiquitous surface-scattering layer and drained layer present on bare, melting sea ice are responsible for its relatively high albedo and relatively low transmittance. Light transmittance through ponded ice depends on the physical thickness of the ice and the magnitude of the scattering coefficient in the ice interior. Bare ice reflects nearly three-quarters of the incident sunlight, enhancing its resiliency to absorption by solar insolation. In contrast, ponded ice absorbs or transmits to the ocean more than three-quarters of the incident sunlight. Characterization of the heat balance of a summertime ice cover is largely dictated by its pond coverage, and light transmittance through ponded ice shows strong contrast between first-year and multiyear Arctic ice covers.

  12. 14 CFR Appendix C to Part 125 - Ice Protection

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Ice Protection C Appendix C to Part 125...—Ice Protection If certification with ice protection provisions is desired, compliance with the following must be shown: (a) The recommended procedures for the use of the ice protection equipment must be...

  13. Performance comparison of hydraulic and gravitation HybridICE ...

    African Journals Online (AJOL)

    HybridICE is an emerging freeze desalination technology for treating complex mine wastewaters. The technology works on the principle that growing ice crystals reject impurities during freezing. The bottleneck in the freeze desalination processes may be the separation of ice from the ice slurry generated in the freeze ...

  14. Validation Ice Crystal Icing Engine Test in the Propulsion Systems Laboratory at NASA Glenn Research Center

    Science.gov (United States)

    Oliver, Michael J.

    2014-01-01

    The Propulsion Systems Laboratory (PSL) is an existing altitude simulation jet engine test facility located at NASA Glenn Research Center in Cleveland, OH. It was modified in 2012 with the integration of an ice crystal cloud generation system. This paper documents the inaugural ice crystal cloud test in PSL--the first ever full scale, high altitude ice crystal cloud turbofan engine test to be conducted in a ground based facility. The test article was a Lycoming ALF502-R5 high bypass turbofan engine, serial number LF01. The objectives of the test were to validate the PSL ice crystal cloud calibration and engine testing methodologies by demonstrating the capability to calibrate and duplicate known flight test events that occurred on the same LF01 engine and to generate engine data to support fundamental and computational research to investigate and better understand the physics of ice crystal icing in a turbofan engine environment while duplicating known revenue service events and conducting test points while varying facility and engine parameters. During PSL calibration testing it was discovered than heated probes installed through tunnel sidewalls experienced ice buildup aft of their location due to ice crystals impinging upon them, melting and running back. Filtered city water was used in the cloud generation nozzle system to provide ice crystal nucleation sites. This resulted in mineralization forming on flow path hardware that led to a chronic degradation of performance during the month long test. Lacking internal flow path cameras, the response of thermocouples along the flow path was interpreted as ice building up. Using this interpretation, a strong correlation between total water content (TWC) and a weaker correlation between median volumetric diameter (MVD) of the ice crystal cloud and the rate of ice buildup along the instrumented flow path was identified. For this test article the engine anti-ice system was required to be turned on before ice crystal

  15. Improving Surface Mass Balance Over Ice Sheets and Snow Depth on Sea Ice

    Science.gov (United States)

    Koenig, Lora Suzanne; Box, Jason; Kurtz, Nathan

    2013-01-01

    Surface mass balance (SMB) over ice sheets and snow on sea ice (SOSI) are important components of the cryosphere. Large knowledge gaps remain in scientists' abilities to monitor SMB and SOSI, including insufficient measurements and difficulties with satellite retrievals. On ice sheets, snow accumulation is the sole mass gain to SMB, and meltwater runoff can be the dominant single loss factor in extremely warm years such as 2012. SOSI affects the growth and melt cycle of the Earth's polar sea ice cover. The summer of 2012 saw the largest satellite-recorded melt area over the Greenland ice sheet and the smallest satellite-recorded Arctic sea ice extent, making this meeting both timely and relevant.

  16. Ice-Shelf Flexure and Tidal Forcing of Bindschadler Ice Stream, West Antarctica

    Science.gov (United States)

    Walker, Ryan T.; Parizek, Bryron R.; Alley, Richard B.; Brunt, Kelly M.; Anandakrishnan, Sridhar

    2014-01-01

    Viscoelastic models of ice-shelf flexure and ice-stream velocity perturbations are combined into a single efficient flowline model to study tidal forcing of grounded ice. The magnitude and timing of icestream response to tidally driven changes in hydrostatic pressure and/or basal drag are found to depend significantly on bed rheology, with only a perfectly plastic bed allowing instantaneous velocity response at the grounding line. The model can reasonably reproduce GPS observations near the grounding zone of Bindschadler Ice Stream (formerly Ice Stream D) on semidiurnal time scales; however, other forcings such as tidally driven ice-shelf slope transverse to the flowline and flexurally driven till deformation must also be considered if diurnal motion is to be matched

  17. A sea ice model for the marginal ice zone with an application to the Greenland Sea

    DEFF Research Database (Denmark)

    Pedersen, Leif Toudal; Coon, Max D.

    2004-01-01

    A model is presented that describes the formation, transport, and desalinization of frazil and pancake ice as it is formed in marginal seas. This model uses as input the total ice concentration evaluated from Special Sensor Microwave Imager and wind speed and direction. The model calculates...... the areal concentration, thickness, volume concentration, and salinity of frazil ice as well as the areal concentration, thickness, and salinity of pancakes. A simple parameterization for the Odden region of the Greenland Sea is presented. The model is run for the winter of 1996-1997. There are direct...... observations of the thickness and salinity of pancakes and the volume concentration of frazil ice to compare with the model. The model results compare very well with the measured data. This new ice model can be tuned to work in marginal seas elsewhere to calculate ice thickness, motion, and brine rejection...

  18. STS-48 ESC Earth observation of ice pack, Antarctic Ice Shelf

    Science.gov (United States)

    1991-01-01

    STS-48 Earth observation taken aboard Discovery, Orbiter Vehicle (OV) 103, is of the breakup of pack ice along the periphery of the Antarctic Ice Shelf. Strong offshore winds, probably associated with katabatic downdrafts from the interior of the continent, are seen peeling off the edges of the ice shelf into long filaments of sea ice, icebergs, bergy bits, and growlers to flow northward into the South Atlantic Ocean. These photos are used to study ocean wind, tide and current patterns. Similar views photographed during previous missions, when analyzed with these recent views may yield information about regional ice drift and breakup of ice packs. The image was captured using an electronic still camera (ESC), was stored on a removable hard disk or small optical disk, and was converted to a format suitable for downlink transmission. The ESC documentation was part of Development Test Objective (DTO) 648, Electronic Still Photography.

  19. Cold pleasure. Why we like ice drinks, ice-lollies and ice cream.

    Science.gov (United States)

    Eccles, R; Du-Plessis, L; Dommels, Y; Wilkinson, J E

    2013-12-01

    This review discusses how the ingestion of cold foods and drinks may be perceived as pleasant because of the effects of cooling of the mouth. The case is made that man has originated from a tropical environment and that cold stimuli applied to the external skin may initiate thermal discomfort and reflexes such as shivering and vasoconstriction that defend body temperature, whereas cold stimuli applied to the mouth are perceived as pleasant because of pleasure associated with satiation of thirst and a refreshing effect. Cold water is preferred to warm water as a thirst quencher and cold products such as ice cream may also be perceived as pleasant because oral cooling satiates thirst. The case is made that cold stimuli may be perceived differently in the skin and oral mucosa, leading to different effects on temperature regulation, and perception of pleasure or displeasure, depending on the body temperature and the temperature of the external environment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Wave-Ice interaction in the Marginal Ice Zone: Toward a Wave-Ocean-Ice Coupled Modeling System

    Science.gov (United States)

    2015-09-30

    as the ship encountered smaller ice floes. The first spectra is shown in dark blue and later spectra transitioning to aqua. SWAN spectra at this time...with no ice representation, is shown in black for reference. Figure 2 below shows the dissipation rate as a function of frequency by several...shown with the black lines. These estimates are created using large numbers of inexpensive simulations for Beaufort and Chukchi Seas in 2012, to

  1. Greenland Ice sheet mass balance from satellite and airborne altimetry

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Bevis, M. G.; Wahr, J. M.

    Ice loss from the Greenland Ice Sheet (GrIS) is dominated by loss in the marginal areas. Dynamic induced ice loss and its associated ice surface lowering is often largest close to the glacier calving front and may vary from rates of tens of meters per years to a few meters per year over relatively...... short distances. Hence, high spatial resolution data are required to accurately estimate volume changes. Here, we estimate ice volume change rate of the Greenland ice sheet using data from Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter during 2003-2009 and CryoSat-2 data during 2010...

  2. The Influence of Ice Properties on Borehole Deformation at the West Antarctic Ice Sheet Divide

    Science.gov (United States)

    Sinkler, E.; Pettit, E. C.; Obbard, R. W.

    2017-12-01

    It is widely known that ice flow is affected by many properties, including crystal fabric and impurities, though these relationships are not fully understood. This study uses data from the West Antarctic Ice Sheet (WAIS) Divide borehole to better determine the influence of such properties on ice flow. The WAIS Divide borehole, the byproduct of the 2006-2012 coring project, offers a unique opportunity to study deep Antarctic Ice. Thanks to the work of many researchers, extensive data on ice properties are available from both coring and borehole logging at this site. The borehole, kept open with a density-approximating fluid, closes and tilts due to ice flow. We have tracked this deformation over two years using a set of repeat measurements with an Acoustic Televiewer. This tool acts as an acoustic caliper allowing us to view cross-sections of the borehole shape and size with up to 1.25 degree azimuthal resolution and a depth resolution as high as 1.4 mm. In addition, the tool collects tilt and azimuth data. These measurements are compared to a 1D Glen's Flow Law model for borehole closure that uses density differences between the ice and borehole fluid as its driving force and incorporates temperature effects. This is then compared to ice properties like crystal fabric and impurities in order to determine the influence of these properties on ice deformation at this site. Crystal fabric has appeared as an important factor in this study.This work builds on that of others who have studied in-situ deep ice through borehole deformation (e.g. Paterson, 1977 and Dahl-Jensen and Gundestrup, 1987). Our results have implications for ice flow modeling and therefore interpretation of depth-age relationships in deep ice cores.

  3. Frazil-ice growth rate and dynamics in mixed layers and sub-ice-shelf plumes

    Science.gov (United States)

    Rees Jones, David W.; Wells, Andrew J.

    2018-01-01

    The growth of frazil or granular ice is an important mode of ice formation in the cryosphere. Recent advances have improved our understanding of the microphysical processes that control the rate of ice-crystal growth when water is cooled beneath its freezing temperature. These advances suggest that crystals grow much faster than previously thought. In this paper, we consider models of a population of ice crystals with different sizes to provide insight into the treatment of frazil ice in large-scale models. We consider the role of crystal growth alongside the other physical processes that determine the dynamics of frazil ice. We apply our model to a simple mixed layer (such as at the surface of the ocean) and to a buoyant plume under a floating ice shelf. We provide numerical calculations and scaling arguments to predict the occurrence of frazil-ice explosions, which we show are controlled by crystal growth, nucleation, and gravitational removal. Faster crystal growth, higher secondary nucleation, and slower gravitational removal make frazil-ice explosions more likely. We identify steady-state crystal size distributions, which are largely insensitive to crystal growth rate but are affected by the relative importance of secondary nucleation to gravitational removal. Finally, we show that the fate of plumes underneath ice shelves is dramatically affected by frazil-ice dynamics. Differences in the parameterization of crystal growth and nucleation give rise to radically different predictions of basal accretion and plume dynamics, and can even impact whether a plume reaches the end of the ice shelf or intrudes at depth.

  4. Sea Ice Summer Camp: Bringing Together Arctic Sea Ice Modelers and Observers

    Science.gov (United States)

    Perovich, D. K.; Holland, M. M.

    2016-12-01

    The Arctic sea ice has undergone dramatic change and numerical models project this to continue for the foreseeable future. Understanding the mechanisms behind sea ice loss and its consequences for the larger Arctic and global systems is of critical importance if we are to anticipate and plan for the future. One impediment to progress is a disconnect between the observational and modeling communities. A sea ice summer camp was held in Barrow Alaska from 26 May to 1 June 2016 to overcome this impediment and better integrate the sea ice community. The 25 participants were a mix of modelers and observers from 13 different institutions at career stages from graduate student to senior scientist. The summer camp provided an accelerated program on sea ice observations and models and also fostered future collaborative interdisciplinary activities. Each morning was spent in the classroom with a daily lecture on an aspect of modeling or remote sensing followed by practical exercises. Topics included using models to assess sensitivity, to test hypotheses and to explore sources of uncertainty in future Arctic sea ice loss. The afternoons were spent on the ice making observations. There were four observational activities; albedo observations, ice thickness measurements, ice coring and physical properties, and ice morphology surveys. The last field day consisted of a grand challenge where the group formulated a hypothesis, developed an observational and modeling strategy to test the hypothesis, and then integrated the observations and model results. The impacts of changing sea ice are being felt today in Barrow Alaska. We opened a dialog with Barrow community members to further understand these changes. This included an evening discussion with two Barrow sea ice experts and a community presentation of our work in a public lecture at the Inupiat Heritage Center.

  5. Regional Changes in the Sea Ice Cover and Ice Production in the Antarctic

    Science.gov (United States)

    Comiso, Josefino C.

    2011-01-01

    Coastal polynyas around the Antarctic continent have been regarded as sea ice factories because of high ice production rates in these regions. The observation of a positive trend in the extent of Antarctic sea ice during the satellite era has been intriguing in light of the observed rapid decline of the ice extent in the Arctic. The results of analysis of the time series of passive microwave data indicate large regional variability with the trends being strongly positive in the Ross Sea, strongly negative in the Bellingshausen/Amundsen Seas and close to zero in the other regions. The atmospheric circulation in the Antarctic is controlled mainly by the Southern Annular Mode (SAM) and the marginal ice zone around the continent shows an alternating pattern of advance and retreat suggesting the presence of a propagating wave (called Antarctic Circumpolar Wave) around the circumpolar region. The results of analysis of the passive microwave data suggest that the positive trend in the Antarctic sea ice cover could be caused primarily by enhanced ice production in the Ross Sea that may be associated with more persistent and larger coastal polynyas in the region. Over the Ross Sea shelf, analysis of sea ice drift data from 1992 to 2008 yields a positive rate-of-increase in the net ice export of about 30,000 km2 per year. For a characteristic ice thickness of 0.6 m, this yields a volume transport of about 20 km3/year, which is almost identical, within error bars, to our estimate of the trend in ice production. In addition to the possibility of changes in SAM, modeling studies have also indicated that the ozone hole may have a role in that it causes the deepening of the lows in the western Antarctic region thereby causing strong winds to occur offthe Ross-ice shelf.

  6. Ice Thickness, Melting Rates and Styles of Activity in Ice-Volcano Interaction

    Science.gov (United States)

    Gudmundsson, M. T.

    2005-12-01

    In most cases when eruptions occur within glaciers they lead to rapid ice melting, jokulhlaups and/or lahars. Many parameters influence the style of activity and its impact on the environment. These include ice thickness (size of glacier), bedrock geometry, magma flow rate and magma composition. The eruptions that have been observed can roughly be divided into: (1) eruptions under several hundred meters thick ice on a relatively flat bedrock, (2) eruptions on flat or sloping bed through relatively thin ice, and (3) volcanism where effects are limitied to confinement of lava flows or melting of ice by pyroclastic flows or surges. This last category (ice-contact volcanism) need not cause much ice melting. Many of the deposits formed by Pleistocene volcanism in Iceland, British Columbia and Antarctica belong to the first category. An important difference between this type of activity and submarine activity (where pressure is hydrostatic) is that pressure at vents may in many cases be much lower than glaciostatic due to partial support of ice cover over vents by the surrounding glacier. Reduced pressure favours explosive activity. Thus the effusive/explosive transition may occur several hundred metres underneath the ice surface. Explosive fragmentation of magma leads to much higher rates of heat transfer than does effusive eruption of pillow lavas, and hence much higher melting rates. This effect of reduced pressure at vents will be less pronounced in a large ice sheet than in a smaller glacier or ice cap, since the hydraulic gradient that drives water away from an eruption site will be lower in the large glacier. This may have implications for form and type of eruption deposits and their relationship with ice thickness and glacier size.

  7. Comparing flow-through and static ice cave models for Shoshone Ice Cave

    Directory of Open Access Journals (Sweden)

    Kaj E. Williams

    2015-05-01

    Full Text Available In this paper we suggest a new ice cave type: the “flow-through” ice cave. In a flow-through ice cave external winds blow into the cave and wet cave walls chill the incoming air to the wet-bulb temperature, thereby achieving extra cooling of the cave air. We have investigated an ice cave in Idaho, located in a lava tube that is reported to have airflow through porous wet end-walls and could therefore be a flow-through cave. We have instrumented the site and collected data for one year. In order to determine the actual ice cave type present at Shoshone, we have constructed numerical models for static and flow-through caves (dynamic is not relevant here. The models are driven with exterior measurements of air temperature, relative humidity and wind speed. The model output is interior air temperature and relative humidity. We then compare the output of both models to the measured interior air temperatures and relative humidity. While both the flow-through and static cave models are capable of preserving ice year-round (a net zero or positive ice mass balance, both models show very different cave air temperature and relative humidity output. We find the empirical data support a hybrid model of the static and flow-through models: permitting a static ice cave to have incoming air chilled to the wet-bulb temperature fits the data best for the Shoshone Ice Cave.

  8. The last Scandinavian ice sheet in northwestern Russia: ice flow patterns and decay dynamics

    DEFF Research Database (Denmark)

    Demidov, L.; Houmark-Nielsen, Michael; Kjær, Kurt Henrik

    2006-01-01

    in Russia than previously outlined and the time of termination at 18-16 cal. kyr BP was almost 10 kyr delayed compared to the southwestern part of the ice sheet. We argue that the lithology of the ice sheets' substrate, and especially the location of former proglacial lake basins, influenced the dynamics......Advance of the Late Weichselian (Valdaian) Scandinavian Ice Sheet (SIS) in northwestern Russia took place after a period of periglacial conditions. Till of the last SIS, Bobrovo till, overlies glacial deposits from the previous Barents and Kara Sea ice sheets and marine deposits of the Last...

  9. Spatial patterning and persistence of meltwater on ice shelves and the implications for ice shelf collapse

    Science.gov (United States)

    Robel, A.; MacAyeal, D. R.; Tsai, V. C.; Shean, D. E.

    2017-12-01

    Observations indicate that for at least the last few decades, there has been extensive surface melting over ice shelves in Antarctica. Meltwater either collects in ponds or flows over the surface in streams that discharge to the ocean. The spatial organization and persistence of this meltwater can have a significant influence on the thermomechanical ice shelf state through albedo, turbulent heat exchange, refreezing and hydrofracture. However, as more meltwater forms on Antarctic ice shelves, there is no general theory that predicts the spatial pattern of meltwater ponded on the ice shelf surface and the volume of meltwater runoff to the ocean. Here, we show how dynamical systems tools, such as cellular automata, can be used to calculate the expected distribution of meltwater on ice shelf surfaces. These tools can also be used to explore how ice shelf surface morphology is modified by meltwater albedo and turbulent heating feedbacks. We apply these numerical approaches to new high-resolution digital elevation models for ice shelves in West Antarctica. Additionally, we survey the prospects of developing general rules of meltwater patterning by applying scaling approaches from percolation theory. We conclude by discussing the types of ice shelves that are more likely to cause ice shelf collapse through surface melt-induced hydrofracture or thermomechanical weakening.

  10. Export of Ice-Cavity Water from Pine Island Ice Shelf, West Antarctica

    Science.gov (United States)

    Thurnherr, Andreas; Jacobs, Stanley; Dutrieux, Pierre

    2013-04-01

    Stability of the West Antarctic Ice Sheet is sensitive to changes in melting at the bottom of floating ice shelves that form the seaward extensions of Antarctic glaciers flowing into the ocean. Not least because observations in the cavities beneath ice shelves are difficult, heat fluxes and melt rates have been inferred from oceanographic measurements obtained near the ice edge (calving fronts). Here, we report on a set of hydrographic and velocity data collected in early 2009 near the calving front of the Amundsen Sea's fast-moving and (until recently) accelerating Pine Island Glacier and its associated ice shelf. CTD profiles collected along the southern half of the meridionally-trending ice front show clear evidence for export of ice-cavity water. That water was carried in the upper ocean along the ice front by a southward current that is possibly related to a striking clockwise gyre that dominated the (summertime) upper-ocean circulation in Pine Island Bay. Signatures of ice-cavity water appear unrelated to current direction along most of the ice front, suggesting that cross-frontal exchange is dominated by temporal variability. However, repeated hydrographic and velocity measurements in a small "ice cove" at the southern end of the calving front show a persistent strong (mean velocity peaking near 0.5 ms-1) outflow of ice-cavity water in the upper 500 m. While surface features (boils) suggested upwelling from deep below the ice shelf, vertical velocity measurements reveal 1) that the mean upwelling within the confines of the cove was too weak to feed the observed outflow, and 2) that large high-frequency internal waves dominated the vertical motion of water inside the cove. These observations indicate that water exchange between the Pine Island Ice Shelf cavity and the Amundsen sea is strongly asymmetric with weak broad inflow at depth and concentrated surface-intensified outflow of melt-laden deep water at the southern edge of the calving front. The lack of

  11. Water, ice and mud: Lahars and lahar hazards at ice- and snow-clad volcanoes

    Science.gov (United States)

    Waythomas, Christopher F.

    2014-01-01

    Large-volume lahars are significant hazards at ice and snow covered volcanoes. Hot eruptive products produced during explosive eruptions can generate a substantial volume of melt water that quickly evolves into highly mobile flows of ice, sediment and water. At present it is difficult to predict the size of lahars that can form at ice and snow covered volcanoes due to their complex flow character and behaviour. However, advances in experiments and numerical approaches are producing new conceptual models and new methods for hazard assessment. Eruption triggered lahars that are ice-dominated leave behind thin, almost unrecognizable sedimentary deposits, making them likely to be under-represented in the geological record.

  12. How accurate are estimates of glacier ice thickness? Results from ITMIX, the Ice Thickness Models Intercomparison eXperiment

    DEFF Research Database (Denmark)

    Farinotti, Daniel; Brinkerhoff, Douglas J.; Clarke, Garry K. C.

    2017-01-01

    Knowledge of the ice thickness distribution of glaciers and ice caps is an important prerequisite for many glaciological and hydrological investigations. A wealth of approaches has recently been presented for inferring ice thickness from characteristics of the surface. With the Ice Thickness Models...

  13. Snow and ice: Chapter 3

    Science.gov (United States)

    Littell, Jeremy; McAfee, Stephanie A.; O'Neel, Shad; Sass, Louis; Burgess, Evan; Colt, Steve; Clark, Paul; Hayward, Gregory D.; Colt, Steve; McTeague, Monica L.; Hollingsworth, Teresa N.

    2017-01-01

    Temperature and precipitation are key determinants of snowpack levels. Therefore, climate change is likely to affect the role of snow and ice in the landscapes and hydrology of the Chugach National Forest region.Downscaled climate projections developed by Scenarios Network for Alaska and Arctic Planning (SNAP) are useful for examining projected changes in snow at relatively fine resolution using a variable called “snowday fraction (SDF),” the percentage of days with precipitation falling as snow.We summarized SNAP monthly SDF from five different global climate models for the Chugach region by 500 m elevation bands, and compared historical (1971–2000) and future (2030–2059) SDF. We found that:Snow-day fraction and snow-water equivalent (SWE) are projected to decline most in late autumn (October to November) and at lower elevations.Snow-day fraction is projected to decrease 23 percent (averaged across five climate models) from October to March, between sea level and 500 m. Between sea level and 1000 m, SDF is projected to decrease by 17 percent between October and March.Snow-water equivalent is projected to decrease most in autumn (October and November) and at lower elevations (below 1500 m), an average of -26 percent for the 2030–2059 period compared to 1971– 2000. Averaged across the cool season and the entire domain, SWE is projected to decrease at elevations below 1000 m because of increased temperature, but increase at higher elevations because of increased precipitation.Compared to 1971–2000, the percentage of the landscape that is snowdominant in 2030–2059 is projected to decrease, and the percentage in which rain and snow are co-dominant (transient hydrology) is projected to increase from 27 to 37 percent. Most of this change is at lower elevations.Glaciers on the Chugach National Forest are currently losing about 6 km3 of ice per year; half of this loss comes from Columbia Glacier (Berthier et al. 2010).Over the past decade, almost all

  14. ENERGY STAR Certified Commercial Ice Machines

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 2.0 ENERGY STAR Program Requirements for Automatic Commercial Ice Makers that are...

  15. Arctic and Southern Ocean Sea Ice Concentrations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly sea ice concentration for Arctic (1901 to 1995) and Southern oceans (1973 to 1990) were digitized on a standard 1-degree grid (cylindrical projection) to...

  16. Great Lakes Aerial Photos of Ice Conditions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The collection consists of approximately 50,000 high-quality negatives and transparencies showing ice cover impact on navigation or hydroelectric operation from 1963...

  17. Workshop on wave-ice interaction

    Science.gov (United States)

    Wadhams, Peter; Squire, Vernon; Rottier, Philip; Liu, Antony; Dugan, John; Czipott, Peter; Shen, Hayley

    The subject of wave-ice interaction has been advanced in recent years by small groups of researchers working on a similar range of topics in widely separated geographic locations. Their recent studies inspired a workshop on wave-ice interaction held at the Scott Polar Research Institute, University of Cambridge, England, December 16-18, 1991, where theories in all aspects of the physics of wave-ice interaction were compared.Conveners of the workshop hoped that plans for future observational and theoretical work dealing with outstanding issues in a collaborative way would emerge. The workshop, organized by the Commission on Sea Ice of the International Association for Physical Sciences of the Ocean (IAPSO), was co-chaired by Vernon Squire, professor of mathematics and statistics at the University of Otago, New Zealand, and Peter Wadhams, director of the Scott Polar Research Institute. Participants attended from Britain, Finland, New Zealand, Norway, and the United States.

  18. International Ice Patrol (IIP) Iceberg Sightings Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The International Ice Patrol (IIP) has been collecting information on iceberg activity in the North Atlantic since 1911. This database contains the data from these...

  19. Russian River Ice Thickness and Duration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of river ice thickness measurements, and beginning and ending dates for river freeze-up events from fifty stations in northern Russia. The...

  20. FY 2013 ICE Immigration Removal Statistics

    Data.gov (United States)

    Department of Homeland Security — In addition to its criminal investigative responsibilities, U.S. Immigration and Customs Enforcement (ICE) shares responsibility for enforcing the nation’s civil...