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Sample records for abu rusheid-sikeit shear

  1. Mineralogy and mineral chemistry of rare-metal pegmatites at Abu Rusheid granitic gneisses, South Eastern Desert, Egypt

    Directory of Open Access Journals (Sweden)

    Mohamed Fahmy Raslan

    2011-12-01

    Full Text Available The Abu Rushied area, situated in the South Eastern Desert of Egypt is a distinctive occurrence of economically important rare-metal mineralization where the host rocks are represented by granitic gneisses. Correspondingly, mineralogical and geochemical investigation of pegmatites pockets scattered within Abu Rusheid granitic gneisses revealed the presence of Hf-zircon, ferrocolumbite and uranyl silicate minerals (uranophane and kasolite. Electronmicroprobe analyses revealed the presence of Nb-Ta multioxide minerals (ishikawaite, uranopyrochlore, and fergusonite, uraninite, thorite and cassiterite as numerous inclusions in the recorded Hf-zircon and ferrocolumbite minerals.Abu Rusheid pegmatites are found as small and large bodies that occur as simple and complex (zoned pegmatites.Abu Rusheid rare-metal pegmatites occur as steeply dipping bodies of variable size, ranging from 1 to 5 m in width and 10 to 50 m in length. The zoned pegmatites are composed of wall zone of coarser granitic gneisses, intermediated zone of K-feldspar and pocket of mica (muscovite and biotite, and core of quartz and pocket ofmica with lenses of rare metals.The zircon is of bipyramidal to typical octahedral form and short prisms. Because the zircon of the investigated Abu Rushied pegmatite frequently contains hafnium in amounts ranging between 2.31 and 11.11%, the studied zircon was designated as Hf-rich zircon. This zircon commonly exhibits a normal zoning with rims consistentlyhigher in Hf than cores. The bright areas in the crystal either in core or rim showed a remarkable enrichment in hafnium content (8.83–11.11% with respect to the dark zones (3.19%. The investigated ferroclumbite commonly exhibits zoning; the dark zone is low in the Ta and U but the light zone is enriched in Ta (13% and U (1%. EMPAanalyses indicate the chemical composition of ishikawaite with U ranging from 0.68 to 0.79 per formula unit.Uranopyrochlore species has dominant uranium in the A

  2. Selective Recovery of Yttrium and Ytterbium Oxides from Abu Rusheid REEs Concentrate via Alkaline Leaching and Solvent Extraction

    International Nuclear Information System (INIS)

    El-Sheikh, E.M.

    2017-01-01

    The REEs concentrate prepared from Abu Rusheid lamprophyre ore material is found to assay 44.65% Y_2O_3 and 13.87% Yb_2O_3 together with less amounts of 10 other REEs. This concentrate has been subjected to alkaline leaching process using seven different alkali reagents (single or mixed). From the obtained results, the mixed Na_2CO_3/(NH_4)HCO_3 reagent has been able to leach up to 87.32 % of Yb and 98.73% of Y together with a minor amount of Eu( 1.44)%. Finally, TBP extractant has been used to separate highly pure Yb and Y concentrate oxides from the nitrate solution

  3. Mohammed Abu-Bajeh

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences. Mohammed Abu-Bajeh. Articles written in Journal of Chemical Sciences. Volume 114 Issue 6 December 2002 pp 675-686. Absolute quantum yield measurements for the formation of oxygen atoms after UV laser excitation of SO2 at 222.4 nm · Mohammed Abu-Bajeh Melanie ...

  4. Genesis of Uranium in the younger granites of gabal abu hawis area, central eastern desert of Egypt

    International Nuclear Information System (INIS)

    Ahmed, F.Y.; Moharem, A.F.

    2003-01-01

    The younger granites cropping out in gabal abu hawis area are considered as uraniferous (fertile) granites (the fertile is mainly is mainly attributed to presence of radioactive zircon). Abu hawis granitic pluton is dissected by joints faults of different trends forming two mineralized shear zones in the northern peripheries and southern border. The younger granites hosting uranium mineralizations along the two mineralized shear zones. The uranium minerals include uranophane and carnotite. The altered granites have much lower Th/U ratios (0.03-0.10) than those of the fresh granites (1.69-2.05), indicating strong mobilization of uranium in this pluton by super-heated solutions that resulted from supergence meteoric water as well as U-addition by hypogene fluids. These solutions could pass through the structural network of fractures, joints and fault planes and have leached some of labile uranium from the surrounding rocks and/or the younger granites themselves. Then, changing in the physicochemical conditions of these solutions caused uranium precipitation as uranium minerals filling the cracks in the rock and/or adsorbed on the surface of clay minerals and iron oxides in the two shear zones

  5. Genesis of the Abu Marawat gold deposit, central Eastern Desert of Egypt

    Science.gov (United States)

    Zoheir, Basem A.; Akawy, Ahmed

    2010-06-01

    Gold mineralisation at the Abu Marawat mine, central Eastern Desert of Egypt, is related to a system of massive and sheared, milky quartz veins cutting a sequence of Neoproterozoic island arc metavolcanic/volcaniclastic rocks and related banded iron formation (BIF). Sulphide-bearing quartz veins and related hydrothermal breccia bodies display a range of textures including sheared, boudinaged and recrystallised quartz, open space filling and microbreccia. These variable textures imply a complex history of crack-seal mechanism characterising the relation between mineral deposition and a major N-S-trending shear zone, during a late brittle-ductile deformation event which affected the area at about 550 Ma. Gold-base metal mineralisation is associated with brecciation and fracturing of the iron ore bands, close to silicified shears and related quartz veins. The auriferous quartz lodes are characterised by the occurrence of visible pyrite-chalcopyrite ± pyrrhotite ± sphalerite ± galena mineralisation. Gold is refractory in pyrite and chalcopyrite, but rare visible gold/electrum and telluride specks were observed in a few samples. Hydrothermal alteration includes pervasive silicification, pyritisation, sericitisation, carbonatisation confined to a delicate set of veins and altered shears, and a more widespread propylitic alteration assemblage (quartz + chlorite + pyrite + calcite ± epidote). Fluid inclusion petrography and microthermometric studies suggest heterogeneous trapping of a low-salinity (1.4-6.7 wt.% eq. NaCl) aqueous solution and a carbonic fluid. Evidence for fluid immiscibility during ore formation includes variable liquid/vapour ratios in inclusions along individual trails and bulk inclusion homogenisation into liquid and occasionally to vapour at comparable temperatures. The trapping conditions of intragranular aqueous-carbonic inclusions approximate 264-378 °C at 700-1300 bar. Similar temperature estimates have been obtained from Al

  6. Abu Dhabi’s New Urban Islands and Shorefront Development

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    El Amrousi Mohamed

    2017-01-01

    Full Text Available Abu Dhabi is in the process of urbanizing a group of Islands that surround its northern and eastern coastlines. Al-Lulu, Al-Saadiyat, Al- Maryah, Al-Reem and Yas Islands are all new urban enclaves that were desert islands and marshlands yet, have been developed over the past decade to urban islands that include epic and entertainment centres such as the Abu Dhabi Louvre, Guggenheim Museum, Ferrari World, NYU Abu Dhabi, the Paris Sorbonne Abu Dhabi in addition to iconic and exclusive waterfront residential units. These new islands re-brand the image of the main archipelago of Abu Dhabi that for decades retained a grid street pattern and pragmatic concrete blocks created in the late 1970s. The new urban islands transform Abu Dhabi’s image into a multinational modern Arab city seeking to become part of the global city network. Abu Dhabi’s new urban islands also act as breakwaters that protect the main archipelago’s coastline from erosion resulting from tidal change, because they are designed to include concrete and stone breakwater barriers. This paper represents a cross-disciplinary research between Civil Engineering and Architecture Departments in an attempt to explore the emerging infrastructure and urban expansion of Abu Dhabi from a multi-disciplinary perspective. We also highlight through simulating the effect of breakwaters on wave heights two scenarios for Al-Lulu Island the importance of these new barrier Islands on the urban expansion of Abu Dhabi.

  7. Torture in Abu Ghraib.

    Science.gov (United States)

    Keller, Allen S

    2006-01-01

    Iraqi detainees subjected to torture and mistreatment at Abu Ghraib prison may continue to suffer from significant physical and psychological consequences of their abuse. This article reports two cases of Iraqi individuals allegedly tortured at Abu Ghraib. Detailed forensic evaluations were conducted approximately one year after their abuse in accordance with international guidelines. The findings of these evaluations substantiate their allegations of torture and confirm the profound health consequences of torture. Furthermore, these cases support assertions that abuse of prisoners was not limited to being perpetrated by guards, but also occurred systematically in the context of interrogations. These cases also raise concerns about inadequate medical care for Iraqi detainees.

  8. Abu Dhabi presses oil development program

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that Abu Dhabi Co. for Onshore Operations (ADCO), the biggest oil producer in the United Arab Emirates, reports 1991 was a successful year despite the Persian Gulf war. Meantime, Abu Dhabi's Zakum, the second largest oil field in the Persian Gulf, boosted production to more than 300,000 b/d, and officials said production will rise further when a platform complex is recommissioned in 1993

  9. Stratigraphy, facies analysis and depositional environments of the Upper Unit of Abu Roash "E" member in the Abu Gharadig field, Western Desert, Egypt

    Science.gov (United States)

    Hewaidy, Abdel Galil; Elshahat, O. R.; Kamal, Samy

    2018-03-01

    Abu Roach "E" member is of an important hydrocarbon reservoir-producing horizon in the Abu Gharadig Field (north Western Desert, Egypt). This study is used to build facies analysis and depositional environments model for the Upper Unit of the Abu Roash "E" member in Abu Gharadig Field. This target has been achieved throughout the sedimentological, wire line logs, lithostratigraphic and biostratigraphic analyses of more than 528 feet cores. The high-resolution biostratigraphic analysis provides a calibration for the paleo-bathymetry and depositional environmental interpretations. Biozonation and lithostratigraphic markers are used to constrain stratigraphic correlation. Integration between the core description and petorographic microfacies analysis by microscope examination provide an excellent indication for the rock types and depositional environments. Five depositional facies types are detected including carbonate inner ramp, tidal flats, tidal channels, supra-tidal and tide dominated delta facies. This model helps in the understanding of the Upper Unit of Abu Roash "E" member reservoir distribution as well as lateral and vertical facies changes that contribute to the development strategy for the remaining hydrocarbon reserves for this important oil reservoir.

  10. Nasr Hamid Abu Zayd as a Modern Muslim Thinker

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    NUR ZAINATUL NADRA ZAINOL

    2014-06-01

    Full Text Available Nasr Hamid Abu Zayd is a thinker who has produced works in the fields of theology, philosophy, law, politics and humanities. Abu Zayd’s thought, partly on the Quran and its hermeneutics has stirred controversy in Egypt and the Muslim world. This research focuses on the controversy surrounding Nasr Hamid Abu Zayd which led to the declaration of his apostasy by the Supreme Court of Egypt in 1995, as well as his controversial thoughts on the Quran, its method of exegesis and certain fiqh (Islamic jurisprudence issues such as the hijab (veil and polygamy. This paper serves as a literature review which employs the content analysis as a methodology to elaborate on Abu Zayd’s controversial thoughts based on his books, as well as through the views of Muslim and Western scholars on those thoughts.

  11. DOCUMENTATION AND MONITORING OF BUILT HERITAGE IN ABU DHABI, UAE

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    S. Muhammad

    2013-07-01

    Full Text Available The ancient oasis-city of Al Ain in Abu Dhabi Emirate still retains the most important and outstanding cultural heritage of United Arab Emirates (UAE. The larger area of Abu Dhabi Emirate comprised of archaeological sites, cultural landscapes and historic buildings dating back to 3rd millennium to the recent pre-oil era. Traditional materials like stone, earth and palm wood were used in combination with local construction methods. For the last seven years the newly formed Abu Dhabi Tourism & Culture Authority (TCA Abu Dhabi1 has been actively involved in conservation of built heritage in Abu Dhabi Emirate with the help of its Conservation Section. Documentation prior to any conservation and restoration works is considered as a basic pre-requisite for understanding an historic building or site. It is a process which continues during the conservation of any monument and is the only accurate tool for recording information in order to understand the structure, ultimately leading to the management of cultural heritage. Application and use of tools, ranging from basic manual techniques to 3D laser scanning, based on the best practices and international guidelines the exercise will help in establishing a documentation lab with standard procedures, specifications and tools for the documentation and monitoring the built heritage of Abu Dhabi Emirate. This paper will discuss a range of case studies and will demonstrate how documentation and monitoring of the built heritage has augmented the various conservation initiatives on a variety of building types.

  12. PREPARASI DAN KARAKTERISASI ZEOLIT DARI ABU LAYANG BATUBARA SECARA ALKALI HIDROTERMAL

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    Jumaeri Jumaeri

    2012-01-01

    Full Text Available Preparasi zeolit dari abu layang batubara PLTU Suralaya secara alkali hidrotermal telah dilakukan. Preparasi dilakukan terhadap abu layang yang telah direfluks dengan HCl 1M dan tanpa refluks. Larutan NaOH dengan konsentrasi tertentu ( 1 ; 2 dan 3 M dicampur dengan abu layang batu bara dengan rasio 10 ml larutan tiap 1 gram abu layang, ke dalam tabung Teflon 100 ml dalam suatu autoclave stainless-steel. Autoclave kemudian dipanaskan pada temperature 80-16 oC selama tiga hari. Zeolit sintesis yang dihasilkan selanjutnya diuji secara kualitatif dengan menggunakan Spektroskopi Inframerah, dan Difraksi Sinar-X. Hasil penelitian menunjukkan bahwa aktivasi abu layang dengan proses alkali hidrotermal dapat menghasilkan material yang mempunyai struktur mirip zeolit (zeolit-like. Produk hidrotermal terdiri dari campuran zeolit (Zeolit P, Zeolit Y serta kristal sodalit dan mullit. Pada temperatur 160 oC, diperoleh zeolit dengan kristalinitas lebih tinggi dari pada 100 oC, baik melalui refluks atau tanpa refluks. Karakteristik zeolit yang terbentuk sangat ditentukan oleh kondisi proses, yang meliputi konsentrasi NaOH, waktu, dan temperatur.

  13. Acceptance for Beneficial Use (ABU) Update for 241-AW-104 Waste Transfer Project

    International Nuclear Information System (INIS)

    MEWES, B.S.

    2001-01-01

    In October of 2000 an Engineering Task Plan (ETP), RPP-6869, was drafted to define objectives, document requirements, and define organizational responsibilities for the purpose of design installation and turnover of the 241-AW-104 Pump Replacement Project The ETP included an Acceptance for Beneficial Use (ABU) checklist, which delineated all tasks necessary to turn the 241-AW-104 Replaced Transfer Pump over to Operations, Maintenance, and Plant Engineering Signature approval of the respective Engineering Data Transmittal (EDT 630501) signified agreement that the ABU checklist was all-inclusive. In January 2001 an additional EDT (EDT 624153) was drafted to define completed ABU items, provide corresponding supporting documentation, and status open items in need of completion. This supporting document is to serve two purposes: (1) update ABU checklist items completed since January 2001, and (2) define remaining ABU checklist items in need of completion

  14. Judicial System Restructuring and Modernization in Abu Dhabi

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    Lawrence Groo

    2008-01-01

    Full Text Available The purpose of this article is to provide a practical overview of the recently initiated modernization of Abu Dhabi’s judicial system. Beginning in 2007, Abu Dhabi’s Government launched a comprehensive effort to transform the Emirate’s judicial system. While the implementation of these reforms is ongoing, with the adoption of the law in May 2007 establishing the new judicial architecture the initial phase of the modernization program is already complete. The restructuring process encompasses court management and administration reform, a new judicial training regime, a redesigned organizational structure for the Emirate’s Judicial Department and courts, and the establishment of a system-wide strategic planning and budgeting process. Many of these initiatives are supported by applying advanced IT-based applications. Given the early achievements and ambitious broader aims of the restructuring process, Abu Dhabi’s example is relevant not only to the other Emirates within the Federal UAE system, but also within the context of the wider Middle East region.

  15. Abu Dhabi-Great Britain and the crisis over jurisdiction 1959-1960

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    Federico Velez

    2011-06-01

    Full Text Available Las demandas presentadas por el Jeque Shakhbout en 1959 para obtener la plena soberanía jurídica sobre el emirato de Abu Dhabi generaron una crisis diplomática plasmada en la correspondencia interna del gobierno Británico. Con sus demandas, el Jeque Shakhbout forzaba a la burocracia a cargo de los Estados de la Tregua – La Oficina de Asuntos Extranjeros en Londres, el representante del gobierno Británico en Bahreín, y los agente administrativos y políticos en Dubai y Abu Dhabi a reexaminar las bases legales de la presencia Británica en la zona y los límites éticos del sistema judicial impuesto sobre sus habitantes. La crisis va mas allá de una discusión sobre los poderes jurisdiccionales. La crisis nos ofrece una ventana a las contradicciones inherentes a la  presencia Británica en la zona, en el marco del movimiento nacionalista árabe y del desarrollo de la industria petrolera y la futura redefinición de la relación entre Abu Dhabi  y la Gran Bretaña.Palabras clave: Abu Dhabi, Gran Bretaña, colonialismo___________________________Abstract:Demands to the British government for supreme jurisdiction over his territory presented by the ruler of Abu Dhabi in 1959 created a diplomatic crisis captured in the internal correspondence of the British government. Sheikh Shakhbout forced the entire bureaucracy that was dealing with the Trucial States – the Foreign Office in London, the British Resident in Bahrain, and the Political and Administrative Agents in Abu Dhabi and Dubai – to reexamine the legality of their presence in the region and the ethical limits of the judicial system imposed on this land.The crisis went beyond the mere discussion over jurisdictional powers. It is also a window into the contradictions linked to the British presence in the region, within the framework of the nascent Arab Nationalist movement and the development of the oil industry . All of which will soon change the nature of the relationship between

  16. 241-SY-101 multi-functional instrument tree acceptance for beneficial use (ABU)

    International Nuclear Information System (INIS)

    Erhart, M.F.

    1995-01-01

    This document formally demonstrates that the ABU process for the 241-SY-101 risers 17B and 17C Multi-functional Instrument Trees (MIT's) has been properly completed in accordance with the approved ABU checklists. For each item required on the ABU Checklist, a bibliography of the documentation prepared and released to satisfy the requirements is provided. Release of this documentation signifies that the tank farm Operations, Engineering, and Maintenance organizations have accepted responsibility for the MIT'S in 241-SY-101 Risers 17B and 17C

  17. Studi Eksperimental Pembuatan Ekosemen dari Abu Sampah dan Cangkang Kerang sebagai Bahan Alternatif Pengganti Semen

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    Frieska Ariesta Syafnijal

    2013-09-01

    Full Text Available Telah dibuat ekosemen dari bahan abu sampah organik dan abu cangkang kerang. Sampah organik dibakar dengan insinerator pada suhu 1000oC. Abu cangkang kerang dipanaskan dengan furnace pada suhu 700oC. Hasil pengujian komposisi awal XRD (X-Ray Diffraction, Abu sampah organik mengandung 69,7% CaCO3; 12,1% KCl; 4% Cd0.15Gd0.85; 3% SiO2; 8,1% Fe ( Se0.5Te0.5 dan 3% Al2ErGe2, Abu cangkang kerang mengandung 100% CaCO3. Ditentukan tiga variasi jumlah komposisi Abu sampah:Abu cangkang kerang yaitu Ekosemen A (58,2%:40%; Ekosemen B (49,1%:49,1% dan Ekosemen C (54,01%:44,09%. Sebagai variabel kontrol digunakan Semen Portland jenis OPC (Ordinary Portland Cement merek ‘Semen Gresik’. Dilakukan pengujian fisika yaitu kuat tekan mortar dan densitas serbuk. Pengujian XRD dilakukan untuk mengetahui komposisi kimia dari ekosemen. Dari hasil pengujian fisika didapat ekosemen B paling mendekati nilai ‘Semen Gresik’ OPC yaitu kuat tekan 3 hari (7,2 kg/cm2 dan densitas serbuk (2,535 gr/ml.   

  18. Modernisation or Westernisation of Johor under Abu Bakar: A Historical Analysis.

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    A Rahman Tang Abdullah

    2008-12-01

    Full Text Available Abstract: The transformation of Johor under Abu Bakar has been variously described as modernisation or westernisation. Westernisation argument is flawed because during the period under consideration, Johor was not yet fully under the control of the West. The archival records show that Johor’s transformation was self-initiated to promote the welfare of the people. The reforms Abu Bakar brought about in Johor affected more the Malay culture than Islamic rules and practices. Even then these reforms not simply modernised but elevated the position of certain aspects of Malay culture. It is, therefore, appropriate to describe Abu Bakar as the father of modern Johor.

  19. Perkembangan Teater di Bali melalui Sosok Dramawan Abu Bakar

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    I Nyoman Darma Putra

    2013-05-01

    Full Text Available Abstract A Western-style of theatre has developed in Bali since the turnof the twentieth century, but it has rarely attracted scholarly attention. Studies on the performing arts in Bali have mainly focused on Balinese (traditional dance and drama. This should come as no surprise given that Balinese dance and drama have developed as a broad and inseparable part of Balinese custom and religious practice. Against this phenomena, this article traces the development of Western-style theatre in Bali through the artistic activities of the prominent playwright, performer and director, Abu Bakar. From the 1960s until the present, Abu Bakar has been an active promoter of Westernsty letheatre in Bali as well as in the main cities of Java andeven in Singapore. He has also has helped students and theatre groups around Bali to study and perform theatre. Initially, Abu Bakar established his own theatre group, Poliklinik, which hascontinued to stage performances as well as collaborating with young people or student theatre study clubs. His extensiverecord of artistic activity has been recorded in newspaper reports and reviews and these form the main source of documentation in this article. By examining qualitative data collected from newspaper archives and interviews, including with Abu Bakar, this article proposes a contemporary historyof theatre or modern drama in Bali.

  20. Abu Kamil algèbre et analyse diophantienne

    CERN Document Server

    Rashed, Roshdi

    2012-01-01

    The mathematical wrks of Abu Kamil (floruit circa 880) were produced two generations after the works of Al-Khwarizmi, the founder of algebra. They opened up fields of research that proved fertile up until the seventeenth century, and were soon to become both a reference and a model. Their influence was decisive on the development of algebra in Arabic no less than in Latin and Hebrew. There will be found in the present publication the first rigorously critical edition of Abu Kamil s works, as well as the first ever translation into a modern language.Text and translation are preceded by an exhau

  1. DELIGNIFIKASI BAMBU PETUNG (DENDROCALAMUS ASPER DENGAN EKSTRAK ABU JERAMI PADI DAN KAYU

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    Endah Sulistiawati

    2012-10-01

    Full Text Available Kebutuhan tekstil di Indonesia terus meningkat seiring dengan bertambahnya jumlah penduduk. Selama ini pemenuhan tekstil sebagian besar diimpor dari beberapa negara, antara lain: India, China, dan Jepang. Di sisi lain, Indonesia merupakan negara agraris, dengan limbah pertanian yang melimpah. Juga tanaman bambu tumbuh subur dan banyak terdapat di negeri ini. Keunggulan serat tekstil bambu adalah bersifat antiseptik, tahan terhadap mikroba. Penelitian ini merupakan salah satu langkah dalam pembuatan serat tekstil alami dari bambu petung (Dendrocalamus asper dan limbah pertanian yaitu abu jerami padi dan kayu, yaitu tahap delignifikasi. Tujuan penelitian ini mencari waktu perendaman bambu dalam ekstrak abu yang memberikan hasil terbaik. Bambu dipotong dan dibelah tipis, berukuran panjang 15 cm, setebal 0,5 mm. Mula-mula sampel bambu ditimbang (antara 12 sampai 57 gram, lalu direndam dalam ekstrak abu (jerami padi dan kayu sebanyak 500 ml dalam sebuah botol berkapasitas 600 ml dan ditutup. Perendaman dilakukan pada suhu kamar. Waktu perendaman bervariasi dari 4 jam hingga 80 jam. Setelah perendaman selesai, hasil disaring. Sampel filtrat dititrasi untuk diketahui konsentrasi alkali aktifnya. Bambu yang telah direndam lalu dikeringkan menggunakan oven pada suhu 110ºC sampai berat tetap. Selisih berat antara bambu awal dan akhir (kering dihitung, dan dianggap sebagai lignin yang terdegradasi. Dari penelitian dapat disimpulkan bahwa perendaman menggunakan ekstrak abu jerami padi memberikan hasil yang lebih baik dari pada ekstrak abu kayu, karena pengurangan berat padatan lebih besar. Hasil yang tertinggi pada perendaman menggunakan ekstrak abu jerami padi selama 76 jam, dengan selisih berat (basis kering mencapai 44,5%.

  2. Abu Ghraib: Prisoner Abuse in the Light of Islamic and International Laws

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    Syed Serajul Islam

    2007-06-01

    Full Text Available Abstract: This study analyses the prisoner abuse at Abu Ghraib in the light of Islamic and International laws. Using documentary sources, the paper argues that Islamic law is far superior than the International law as enshrined in the Geneva Conventions and the United Nations Charter on the treatment of prisoners of war. It found the abuse of the prisoners at Abu Ghraib a routine operation carried out in obedience to orders issued by the higher authorities. The photographs portraying images of dehumanization in Abu Ghraib is unacceptable either in Islamic or international law.

  3. Middle East gas export projects: The case of Abu Dhabi

    International Nuclear Information System (INIS)

    Al Marzooqi, H.

    1995-01-01

    Abu Dhabi is ranked in the industry journals in the top 5 in the world tables of both oil and gas reserves. Gas is produced both Onshore and Offshore from associated and non-associated fields. Production has tripped during the last ten years and will increase further in the next few years as a result of current and planned investment. Development of Abu Dhabi's gas resources is aimed at enhancing oil production and recovery, meeting local and export demand and eliminating waste. Companies in Abu Dhabi are involved in all the main sectors of gas industry including production, processing, transportation and sales. The first large LNG export project by sea in Arabian Gulf was established in 1977 from Abu to Japan. Development continues and the gas is exported as LNG and is also processed into LPG and Pentane Plus for export. Japan remains the main market. The volume of Condensate available for export and processing will increase significantly in the next few years. In order to ensure a continuing and increasing supply of gas to world markets, in future years, prices will need to provide an adequate return on investment and should also reflect the environmental advantages of gas. 9 tabs

  4. Do the Photos Tell it All? Representing Torture in the Images from Abu Ghraib

    OpenAIRE

    Dauenhauer, Katrin

    2009-01-01

    In 2004, pictures of U.S. military personnel abusing detainees of the Abu Ghraib prison came to public attention, triggering a new debate on torture. This essay examines the shock potential of the photographs from Abu Ghraib as well as the representability of pain. It argues that the role of photography in the Abu Ghraib torture scandal is a complex and complicated one, oscillating between becoming complicit in the torture and exposing it.

  5. In the remote western desert oasis of Egypt -Abu Minqar community ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Nesrine

    Les habitants du village oasien d'Abu Minqar, au centre du désert occidental, ont démontré que les populations peuvent prendre en mains leurs ressources et en assurer une gestion des plus efficaces et équitables. Comme tous les habitants de l'oasis de Farafra, les agriculteurs d'Abu. Minqar font face à nombreux défis ...

  6. TRADISI FIQH DALAM PEMIKIRAN KHALID ABU AL-FADL

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    Qurrotul Ainiyah

    2016-09-01

    Full Text Available This research is descriptive and reflective, with lifting the theme "Tradition Fiqh Thought Khalid Abu al-Fadl", the theme is intended to explore the key ideas of Khalid discourse on contemporary Islamic legal by analyzing one of his main work, Speaking in God's Name: Islamic Law, Authority, and Women.dengan using content analysis approach to examine in depth the ideas Khalid Abu al-Fadl of Islamic law, the results of this study is the ideology of Salafism Khalid Critics argue that Islamic reformism partly responsible for creating credo closed, intolerant, and shallow in understanding the sacred texts of Islam deserves to be taken seriously.   Keywords: Fiqh, Khalid

  7. Introduction of an Emergency Response Plan for flood loading of Sultan Abu Bakar Dam in Malaysia

    Science.gov (United States)

    Said, N. F. Md; Sidek, L. M.; Basri, H.; Muda, R. S.; Razad, A. Z. Abdul

    2016-03-01

    Sultan Abu Bakar Dam Emergency Response Plan (ERP) is designed to assist employees for identifying, monitoring, responding and mitigation dam safety emergencies. This paper is outlined to identification of an organization chart, responsibility for emergency management team and triggering level in Sultan Abu Bakar Dam ERP. ERP is a plan that guides responsibilities for proper operation of Sultan Abu Bakar Dam in respond to emergency incidents affecting the dam. Based on this study four major responsibilities are needed for Abu Bakar Dam owing to protect any probable risk for downstream which they can be Incident Commander, Deputy Incident Commander, On-Scene Commander, Civil Engineer. In conclusion, having organization charts based on ERP studies can be helpful for decreasing the probable risks in any projects such as Abu Bakar Dam and it is a way to identify and suspected and actual dam safety emergencies.

  8. Crimes of obedience: "groupthink" at abu ghraib.

    Science.gov (United States)

    Post, Jerrold M; Panis, Lara K

    2011-01-01

    Clear evidence of authorization at the highest levels belies administration statements to the effect that the torture at Abu Ghraib was an aberration and simply unauthorized actions by rogue soldiers. The administration reflected a "group mind," demonstrating many qualities of "groupthink." Whatever was necessary, including torture and violation of the Geneva accords, the system in effect authorized, because of the perceived danger to the system and the desperate requirement to get the information out of "them" by whatever means necessary, information that could save lives. The sanctioned violence demonstrated the qualities identified by Kelman and Hamilton (1989) in their study of the Mylai massacre as characteristic of sanctioned massacres: authorization, routinization, and dehumanization. It would seem that officials and participants exhibited all of these characteristics in the decision to conduct extreme interrogation on the "unlawful combatants" imprisoned at Abu Ghraib.

  9. Stated preferences for future management developments in the hospitality sector: a case study of Abu Dhabi, UAE

    OpenAIRE

    Al Suwaidi, Hamed

    2014-01-01

    Abu-Dhabi (AD) is the largest of the seven Emirates that comprise the United Arab Emirates. Abu-Dhabi, the capital of the UAE with 1,493,000 inhabitants, accounts for 86.7% of the total surface area of the state. The emirate of Abu-Dhabi, through its Policy Agenda 2007-2008, the strategic Plan 2008-2012 and the Plan Vision Abu-Dhabi 2030 has recently re-branded itself and has made a series of assertive moves in order to boost the tourism and hospitality sectors as a means to a more diversifie...

  10. Modernisation or Westernisation of Johor under Abu Bakar: A Historical Analysis.

    OpenAIRE

    A Rahman Tang Abdullah

    2008-01-01

    Abstract: The transformation of Johor under Abu Bakar has been variously described as modernisation or westernisation. Westernisation argument is flawed because during the period under consideration, Johor was not yet fully under the control of the West. The archival records show that Johor’s transformation was self-initiated to promote the welfare of the people. The reforms Abu Bakar brought about in Johor affected more the Malay culture than Islamic rules and practices. Even then these refo...

  11. Pembuatan dan Pengujian Kualitas Semen Portland Yang Diperkaya Silikat Abu Ampas Tebu

    OpenAIRE

    Suci Wulandari, Indah Pratama

    2015-01-01

    Penelitian ini mengkaji pengaruh penambahan abu ampas tebu terhadap kuat tekan mortar dan sifat fisis semen portland komposit, meliputi: kehalusan semen, kebutuhan air semen, waktu pengikatan semen, pemuaian dan komposisi kimia semen. Dari hasil penelitian, besar kuat tekan pada penggunaan abu ampas tebu dengan kadar 9% merupakan penambahan optimum pada mortar yang direndam larutan kapur jenuh Sedangkan dari hasil pengujian fisis yang meliputi kehalusan semen, kebutuhan air semen, waktu pengi...

  12. Coincident Observations of Surface Ozone and NMVOCs over Abu Dhabi

    Science.gov (United States)

    Abbasi, Naveed; Majeed, Tariq; Iqbal, Mazhar; Tarasick, David; Davies, Jonathan; Riemer, Daniel; Apel, Eric

    2016-07-01

    The vertical profiles of ozone are measured coincidently with non-methane volatile organic compounds (NMVOCs) at the meteorological site located at the Abu Dhabi international airport (latitude 24.45N; longitude 54.22E) during the years 2012 - 2014. Some of the profiles show elevated surface ozone >95 ppbv during the winter months (December, January and February). The ground-level NMVOCs obtained from the gas chromatography-flame ionization detection/mass spectrometry system also show elevated values of acetylene, ethane, propane, butane, pentane, benzene, and toluene. NMVOCs and ozone abundances in other seasons are much lower than the values in winter season. NMVOCs are emitted from an extensive number of sources in urban environments including fuel production, distribution, and consumption, and serve as precursor of ozone. Transport sources contribute a substantial portion of the NMVOC burden to the urban atmosphere in developed regions. Abu Dhabi is located at the edge of the Arabian Gulf and is highly affected by emissions from petrochemical industries in the neighboring Gulf region. The preliminary results indicate that wintertime enhancement in ozone is associated with large values of NMVOCs at Abu Dhabi. The domestic production of surface ozone is estimated from the combination of oxygen recombination and NMVOCs and compared with the data. It is estimated that about 40-50% of ozone in Abu Dhabi is transported from the neighbouring petrochemical industries. We will present ozone sounding and NMVOCs data and our model estimates of surface ozone, including a discussion on the high levels of the tropospheric ozone responsible for contaminating the air quality in the UAE. This work is supported by National Research Foundation, UAE.

  13. Balik-Terrorism: The Return of the Abu Sayyaf

    National Research Council Canada - National Science Library

    Abuza, Zachary

    2005-01-01

    ...), a group previously known for its brutal, though hardly political, kidnappings. Though "Abu Sayyaf" is usually proceeded with the words the "al Qaeda-linked," there was little tangible evidence of such a link from the mid-1990s to 2002...

  14. PERBANDINGAN KEMAMPUAN SILIKA GEL DARI ABU SABUT KELAPA DAN ABU SEKAM PADI UNTUK MENURUNKAN KADAR LOGAM Cd2+

    Directory of Open Access Journals (Sweden)

    AF Yusrin

    2015-07-01

    Full Text Available Penelitian mengenai pembuatan silika gel dari bahan baku abu sabut kelapa (ASK dan abu sekam padi (ASP telah dilakukan dengan memanfaatkan kandungan silikanya. Bahan baku ASK dan ASP ditambah larutan NaOH dengan pemanasan dan peleburan pada suhu 500C selama 30 menit menghasilkan larutan natrium silikat, kemudian larutan natrium silikat masing-masing diasamkan dengan HCl 3 M hingga pH 7 dan dikeringkan hingga menjadi silika gel abu sabut kelapa (SG-ASK dan silika gel abu sekam padi (SG-ASP. Hasil karakterisasi XRD menyatakan bahwa SG-ASK dan SG-ASP menghasilkan silika berbentuk amorf, sedangkan hasil analisis FT-IR menyatakan bahwa silika gel memiliki gugus fungsi Si-OH, Si-O dan Si-H. Hasil penelitian mengenai uji penyerapan ion logam Cd2+ menunjukkan bahwa penyerapan optimum ion logam Cd2+ dalam larutan oleh SG-ASK adalah pada pH 6, waktu kontak 60 menit dan konsentrasi optimum 7,45 ppm. Hasil uji penyerapan optimum ion logam Cd2+ dalam larutan oleh SG-ASP pada pH 7, waktu kontak 90 menit dan konsentrasi optimum 11,78 ppm. Hasil penelitian menunjukkan bahwa kemampuan SG-ASP lebih besar dibandingkan dengan kemampuan SG-ASK dalam menurunkan kadar ion logam Cd2+ dalam larutan.Research on the manufacture of gel silica from coconut husk ash (ASK and rice husk ash (ASP has been conducted by utilizing their silica contents. ASK and ASP were added by an NaOH solution, then by heated and melted at temperature 500C for 30 minutes to produce sodium silicate solution. The solution was then acidified separately with HCl 3 M up to pH 7 and dried into silica gel of coconut husk ash (SG-ASK and silica gel of rice husk ash (SG-ASP. The result of XRD characterization showed that SG-ASK and SG-ASP both produced amorphous silica, while the result of FT-IR analysis showed that silica gel had functional groups of Si-OH, Si-O and Si-H. The research on the test adsorption of Cd2+ metal ions showed that the optimum adsorption of Cd2+ metal ions in solution by SG

  15. Designing Professional Development for Principals in a Context of Change: The Case of Abu Dhabi

    Science.gov (United States)

    Blaik Hourani, Rida; Stringer, Patricia

    2015-01-01

    Schools in Abu Dhabi are going through a period of transformation and reform. The Abu Dhabi Education Council commenced a professional development plan for principals to enhance their capabilities to manage and initiate change in light of the reforms. This study was conducted to explore principals' perspectives on professional development…

  16. PEMANFAATAN ABU VULKANIK GUNUNG MERAPI SEBAGAI GEOPOLIMER (SUATU POLIMER ANORGANIK ALUMINOSILIKAT

    Directory of Open Access Journals (Sweden)

    E. Kusumastuti

    2012-09-01

    Full Text Available Sintesis geopolimer telah dilakukan dengan memanfaatkan abu vulkanik Gunung Merapi. Geopolimer merupakan suatu polimer anorganik aluminosilikat dengan rantai Si-O-Al yang disintesis dari material yang kaya akan silika dan alumina dengan larutan pengaktif natrium hidroksida. Analisis kandungan kimia abu vulkanik Merapi menunjukkan bahwa material ini termasuk material pozzolan dengan kandungan silika dan alumina yang tinggi, yakni 45,7% berat SiO2; 14,00% berat Al2O3; 16,1% berat CaO; 18,2% berat Fe2O3 dan 3,86% berat K2O. Perbandingan mol SiO2/Al2O3 dalam abu vulkanik Merapi tergolong tinggi yakni 5,55. Abu vulkanik Merapi dapat disintesis menjadi geopolimer meskipun mempunyai rasio mol SiO2/Al2O3 yang tinggi dengan menggunakan larutan pengaktif NaOH 66,67% serta menambah waktu curing selama 3 hari pada suhu 70°C untuk membantu proses kondensasi (lepasnya molekul air pada proses geopolimerisasinya. Geopolimerisasi abu vulkanik Merapi pada suhu kamar tidak dapat terjadi, ditandai dengan kekuatannya yang sangat rendah. Karakterisasi pada geopolimer berbahan dasar abu vulkanik menunjukkan bahwa kuat tekan optimum dicapai pada komposisi dengan perbandingan abu vulkanik/Na silikat/NaOH/H2O sebesar 50/10/4/6 dengan kekuatan 61,16 MPa. Analisis kualitatif berupa fasa mineral dengan XRD dan ikatan kimia dengan FTIR menunjukkan bahwa telah terbentuk fasa amorf aluminosilikat geopolimer dengan ikatan Si–O–Si atau Si–O–Al. Synthesis of geopolymer has been done by using Merapi volcanic ash. Geopolymer is an aluminosilicate inorganic polymer with Si-O-Al chain that has been synthesized from silica-and alumina-rich materials by using activator solution natrium hydroxide. The analysis of Merapi volcanic ash content showed that it was a pozzolan material containing high-silica alumina, with 45,7% of SiO2; 14,00% of Al2O3; 16,1% of  CaO; 18,2% of Fe2O3 and 3,86% of K2O. Mol ratio of SiO2/Al2O3 was high, it is 5,55. Although it

  17. The meaning of education after Abu Ghraib: revisiting Adorno’s politics of education O que pode significar a educação após Abu Ghraib: revisitando a política de educação de Adorno

    Directory of Open Access Journals (Sweden)

    Henry A. Giroux

    2010-05-01

    Full Text Available How might education be used to question the common sense of the war on terrorism or to rouse citizens to challenge the social, political, and cultural conditions that led to the horrible events of Abu Ghraib? Just as crucially, we must ponder the limits of education. Is there a point where extreme conditions shortcircuit our moral instincts and ability to think and act rationally? If this is the case, what responsibility do we have to challenge the reckless violence-as-fi rst-resort ethos of the Bush administration? Such questions extend beyond the events of Abu Ghraib, but, at the same time, Abu Ghraib provides an opportunity to connect the sadistic treatment of Iraqi prisoners to the task of redefi ning pedagogy as an ethical practice, the sites in which pedagogy takes place, and the consequences of pedagogy to rethinking the meaning of politics in the twenty-fi rst century. In order to confront the pedagogical and political challenges arising from the reality of Abu Ghraib, I want to revisit a classic essay by Theodor Adorno in which he tries to grapple with the relationship between education and morality in light of the horrors of Auschwitz. Keywords: Education. Adorno. Auschwitz. Abu Ghraib. Como pode a educação ser usada para questionar o senso comum da guerra ao terrorismo ou para insuflar os cidadãos a desafi ar as condições sociais, políticas e culturais que conduziram aos eventos horríveis de abusos contra prisioneiros iraquianos na prisão americana de Abu Ghraib? Só assim, de modo crucial, podemos ponderar os limites da educação. Até que ponto as condições extremas causam curto-circuito em nossos instintos morais e em nossa capacidade de pensar e agir racionalmente? Se for esse o caso, qual nossa responsabilidade em desafi ar o etos imprudente da “violência como primeiro recurso” da administração de Bush? Tais questões estendem-se além dos eventos de Abu Ghraib, mas, ao mesmo tempo, Abu Ghraib fornece uma

  18. Reading teh Myth: Public Teaching of Abu Bakar Ba'asyir

    Directory of Open Access Journals (Sweden)

    Timothy Earl Behrend

    2003-12-01

    Full Text Available Abu Bakar Ba 'asyir, menurut media di luar Indonesia, dituduh sebagai penganjur terorisme dan revolusi melalui organisasi yang disebut Jamaah Islamiyah. Namanya sering dikaitkan dengan Al Qaidah, dan sejumlah peristiwa terorisme. Ia ditangkap karena desakan sejumlah negara atas Indonesia, melalui tuduhan sebagai aktor terorisme. Abu Bakar Ba'asyir sendiri merupakan seorang muslim taat, disiplin, tetapi juga absolutis dan simplistis. Ia memang, melalui pengajarannya, tampak berobsesi menegakkan syari'at Islam di negara Indonesia, untuk mengganti sistem kafir. Dalam hal ini, ia seorang radikalis. Tetapi, sesungguhnya ia bukan penganjur terorisme dan kekerasan dalam mencapai tujuannya, sebagaimana dituduhkan media. Sikap radikalnya, sesungguhnya, tak beda dengan sikap radikal kaum Kristen fundamentalis yang pernah terjadi di barat, terutama Amerika Serikat. Selain itu, ia juga sangat menentang Amerika yang dipandangnya telah melakukan hegemoni dan terorisme budaya.

  19. Communication and Collaboration in Library Technical Services: A Case Study of New York University in Abu Dhabi

    Science.gov (United States)

    Parrott, Justin

    2016-01-01

    New York University Abu Dhabi Library has developed new strategies to increase efficiency in technical services processing between units based in New York and Abu Dhabi. This case study discusses the challenges specific to the international context and the methods used to overcome them, increase speed processing, and ultimately improve patron…

  20. Prediction of soil shear strength in agricultural and natural environments of the Brazilian Cerrado

    Directory of Open Access Journals (Sweden)

    Reginaldo Barboza da Silva

    2015-01-01

    Full Text Available The objective of this work was to develop uni- and multivariate models to predict maximum soil shear strength (τmax under different normal stresses (σn, water contents (U, and soil managements. The study was carried out in a Rhodic Haplustox under Cerrado (control area and under no-tillage and conventional tillage systems. Undisturbed soil samples were taken in the 0.00-0.05 m layer and subjected to increasing U and σn, in shear strength tests. The uni- and multivariate models - respectively τmax=10(a+bU and τmax=10(a+bU+cσn - were significant in all three soil management systems evaluated and they satisfactorily explain the relationship between U, σn, and τmax. The soil under Cerrado has the highest shear strength (τ estimated with the univariate model, regardless of the soil water content, whereas the soil under conventional tillage shows the highest values with the multivariate model, which were associated to the lowest water contents at the soil consistency limits in this management system.

  1. Measurement of solar energy radiation in Abu Dhabi, UAE

    Energy Technology Data Exchange (ETDEWEB)

    Islam, M.D.; Kubo, I.; Ohadi, M.; Alili, A.A. [Department of Mechanical Engineering, The Petroleum Institute, Abu Dhabi, P.O. Box 2533 (United Arab Emirates)

    2009-04-15

    This paper presents data on measurement of actual solar radiation in Abu Dhabi (24.43 N, 54.45 E). Global solar radiation and surface temperatures were measured and analyzed for one complete year. High resolution, real-time solar radiation and other meteorological data were collected and processed. Daily and monthly average solar radiation values were calculated from the one-minute average recorded values. The highest daily and monthly mean solar radiation values were 369 and 290 W/m{sup 2}, respectively. The highest one-minute average daily solar radiation was 1041 W/m{sup 2}. Yearly average daily energy input was 18.48 MJ/m{sup 2}/day. Besides the global solar radiation, the daily and monthly average clearness indexes along with temperature variations are discussed. When possible, global solar energy radiation and some meteorological data are compared with corresponding data in other Arab state capitals. The data collected indicate that Abu Dhabi has a strong potential for solar energy capture. (author)

  2. Measurement of solar energy radiation in Abu Dhabi, UAE

    International Nuclear Information System (INIS)

    Islam, M.D.; Kubo, I.; Ohadi, M.; Alili, A.A.

    2009-01-01

    This paper presents data on measurement of actual solar radiation in Abu Dhabi (24.43 deg. N, 54.45 deg. E). Global solar radiation and surface temperatures were measured and analyzed for one complete year. High resolution, real-time solar radiation and other meteorological data were collected and processed. Daily and monthly average solar radiation values were calculated from the one-minute average recorded values. The highest daily and monthly mean solar radiation values were 369 and 290 W/m 2 , respectively. The highest one-minute average daily solar radiation was 1041 W/m 2 . Yearly average daily energy input was 18.48 MJ/m 2 /day. Besides the global solar radiation, the daily and monthly average clearness indexes along with temperature variations are discussed. When possible, global solar energy radiation and some meteorological data are compared with corresponding data in other Arab state capitals. The data collected indicate that Abu Dhabi has a strong potential for solar energy capture

  3. Weqaya: A Population-Wide Cardiovascular Screening Program in Abu Dhabi, United Arab Emirates

    Science.gov (United States)

    Harrison, Oliver; Al Siksek, Zaid

    2012-01-01

    Objectives. We sought to determine cardiovascular risk factor prevalence rates among adults in Abu Dhabi, United Arab Emirates. Methods. We used self-reported indicators, anthropometric measures, and blood tests to screen 50 138 adults aged 18 years or older taking part in a population-wide cardiovascular screening program. Results. Participants’ mean age was 36.82 years (SD = 14.3); 43% were men. Risk factor prevalence rates were as follows: obesity, 35%; overweight, 32%; central obesity, 55%; diabetes, 18%; prediabetes, 27%; dyslipidemia, 44%; and hypertension, 23.1%. In addition, 26% of men were smokers, compared with 0.8% of women. Age-standardized diabetes and prediabetes rates were 25% and 30%, respectively, and age-standardized rates of obesity and overweight were 41% and 34%. Conclusions. This population-wide cardiovascular screening program demonstrated a high cardiovascular burden for our small sample in Abu Dhabi. The data form a baseline against which interventions can be implemented and progress monitored as part of the population-wide Abu Dhabi Cardiovascular Disease Program. PMID:21940918

  4. Implementing a multifaceted intervention to decrease central line-associated bloodstream infections in SEHA (Abu Dhabi Health Services Company) intensive care units: the Abu Dhabi experience.

    Science.gov (United States)

    Latif, Asad; Kelly, Bernadette; Edrees, Hanan; Kent, Paula S; Weaver, Sallie J; Jovanovic, Branislava; Attallah, Hadeel; de Grouchy, Kristin K; Al-Obaidli, Ali; Goeschel, Christine A; Berenholtz, Sean M

    2015-07-01

    OBJECTIVE To determine whether implementation of a multifaceted intervention would significantly reduce the incidence of central line-associated bloodstream infections. DESIGN Prospective cohort collaborative. SETTING AND PARTICIPANTS Intensive care units of the Abu Dhabi Health Services Company hospitals in the Emirate of Abu Dhabi. INTERVENTIONS A bundled intervention consisting of 3 components was implemented as part of the program. It consisted of a multifaceted approach that targeted clinician use of evidence-based infection prevention recommendations, tools that supported the identification of local barriers to these practices, and implementation ideas to help ensure patients received the practices. Comprehensive unit-based safety teams were created to improve safety culture and teamwork. Finally, the measurement and feedback of monthly infection rate data to safety teams, senior leaders, and staff in participating intensive care units was encouraged. The main outcome measure was the quarterly rate of central line-associated bloodstream infections. RESULTS Eighteen intensive care units from 7 hospitals in Abu Dhabi implemented the program and achieved an overall 38% reduction in their central line-associated bloodstream infection rate, adjusted at the hospital and unit level. The number of units with a quarterly central line-associated bloodstream infection rate of less than 1 infection per 1,000 catheter-days increased by almost 40% between the baseline and postintervention periods. CONCLUSION A significant reduction in the global morbidity and mortality associated with central line-associated bloodstream infections is possible across intensive care units in disparate settings using a multifaceted intervention.

  5. ANALISIS EKONOMI ISLAM TERHADAP BAGI HASIL PEMBIAYAAN MUDHARABAH UNTUK USAHA MIKRO PADA BAITUL QIRADH ABU INDRAPURI

    Directory of Open Access Journals (Sweden)

    Jumadi Jumadi

    2013-06-01

    Full Text Available This study generally aims to analyze the concept of mudharabah financing in Baitul Qiradh (BQ Abu Indrapuri for micro-enterprises. Specifically, the paper reviews the systems implemented in the management and revenue-sharing mechanisms derived from these micro-enterprises. This study employs primary and secondary data which were collected through interview and documentation studies. The data were analyzed using descriptive analysis method. The findings show that generally the concept of mudharabah financing in BQ Abu Indrapuri is based on Fatwa Dewan Syariah Nasional No. 07/DSN/MUI/IV/2000. In the implementation level, however, the application of profit sharing and collateral system was not fully shariah compliance. The imbalance between the concept and implementation because the BQ still refers to the conventional banking rules. =========================================== Penelitian ini secara umum bertujuan untuk menganalisis konsep pembiayaan mudharabah pada Baitul Qiradh (BQ Abu Indrapuri untuk usaha mikro. Secara spesifik, tulisan mengkaji tentang sistem yang diterapkan dalam pengelolaan dan mekanisme pembagian pendapatan yang diperoleh dari usaha mikro tersebut. Penelitian ini menggunakan data primer dan sekunder yang dikumpulkan dengan teknik wawancara bebas, dan studi dokumentasi. Data yang diperoleh dianalisis dengan menggunakan metode deskriptif analisis. Hasil penelitian menunjukkan bahwa secara umum konsep pembiayaan mudharabah pada BQ Abu Indrapuri berpedoman pada Fatwa Dewan Syariah Nasional No.07/DSN/MUI/IV/2000. Akan tetapi, dalam implementasinya masih terdapat hal-hal yang tidak sesuai dengan konsep syariah yaitu pada sistem bagi hasil dan jaminan. Terdapat ketimpangan antara konsep dan implementasi disebabkan karena BQ Abu Indrapuri masih mengacu pada aturan sistem perbankan konvensional.

  6. Reflections on the Reggio Emilia Approach as Inspiration for Early Childhood Teacher Education in Abu Dhabi, UAE

    Science.gov (United States)

    Baker, Fiona S.

    2015-01-01

    This article discusses a teacher educator's reflections on her participation in an international study group and visits to the infant-toddler and pre-schools of Reggio Emilia, Italy, as inspiration for early childhood teacher education in Abu Dhabi, UAE. The following five themes are reflected on, for teacher education in the context of Abu Dhabi:…

  7. Science as Interests but Not for Career: Understanding High School Students' Engagement in Science in Abu Dhabi

    Science.gov (United States)

    Yang, Guang; Badri, Masood; Al-Mazroui, Karima; Al-Rashedi, Asma; Nai, Peng

    2017-01-01

    Understanding high school students' engagement in science is important for the Emirate of Abu Dhabi. Drawing on data from the ROSE Survey conducted in Abu Dhabi schools in 2013, this paper used a multi-dimensional framework to explore associations between high school students' engagement in science and a range of student psychosocial and…

  8. OIL SPILL DETECTION AND MONITORING OF ABU DHABI COASTAL ZONE USING KOMPSAT-5 SAR IMAGERY

    OpenAIRE

    H. A. Harahsheh

    2016-01-01

    Abu Dhabi Government endorsed vision for its Maritime Strategy ‘A safe, secure and sustainable maritime domain for Abu Dhabi'. This research study share this vision using the concept of monitoring as tool for marine protection against any possible oil pollution. The best technology to detect and monitor oil pollution and in particularly oil spill is SAR imagery In this case study we chose KOMPSAT-5 SAR. KOMPSAT-5 carries X-band SAR for earth observation, and is capable of day-...

  9. Parking problems in Abu Dhabi, UAE toward an intelligent parking management system “ADIP: Abu Dhabi Intelligent Parking”

    OpenAIRE

    Alkheder, Sharaf A.; Al Rajab, Murad M.; Alzoubi, Khalid

    2016-01-01

    Car parking is a serious problem in Gulf Cooperation Council (GCC) countries in general and in United Arab Emirates (UAE) in particular. This problem has been associated with the exceptional growth in the number of cars, buses, trucks, and other modes of transportation over the past few decades. In Abu Dhabi (the capital city of UAE), finding a parking at some locations is a real challenge due to the lack of available parking slots in the city. In 2009, in order to organize the randomness in ...

  10. Comunicación y territorialización. Extraños en Abu Ghraib

    Directory of Open Access Journals (Sweden)

    Cristina Peñamarín

    2009-01-01

    Full Text Available El trabajo estudia los medios en los procesos de territorialización y de formación de “causas colectivas”, que mueven la acción política, en los discursos públicos durante la guerra de Irak y en las fotografías de Abu Ghraib. Para ello, analiza la transmisión de emociones colectivizadoras de acuerdo con las diferentes categorizaciones de los otros. The paper studies media in territory processes and the formation of "collective causes", that can move political action, in public discourses during Iraq war and in Abu Ghraib pictures. For this purpose, it analyses transmission of collective emotions based on different categories of “the others”.

  11. Global solar radiation: Multiple on-site assessments in Abu Dhabi, UAE

    Energy Technology Data Exchange (ETDEWEB)

    El Chaar, Lana; Lamont, Lisa A. [Petroleum Institute, Electrical Engineering Department, P.O. Box 2533, Abu Dhabi (United Arab Emirates)

    2010-07-15

    Renewable energy technology and in particular solar energy is being considered worldwide due to the fluctuations in oil prices, global warming and the growing demand for energy supply. This paper investigates the climate conditions available in the United Arab Emirates (UAE) in particular Abu Dhabi to implement Photovoltaic (PV) technology. Measured solar radiation was analyzed for five different geographical locations to ensure the suitability of this region. Hourly, daily and monthly global horizontal irradiation (GHI) were collected and processed. Statistical methods were used to evaluate the computed GHI and showed high values especially during the summer period. Moreover, clearness index was calculated to investigate the frequency of cloudy sky days and results have shown a high percentage of clear days during the year. This paper highlights a promising future for Abu Dhabi in the solar energy sector and in particular Photovoltaic (PV) technology. (author)

  12. Abu Sayyaf Group (ASG): An Al-Qaeda Associate Case Study

    Science.gov (United States)

    2017-10-01

    Enduring Freedom -Philippines PNP Philippine National Police viii PSF Philippine Security Forces SAF Special Action Forces SOF...Enduring Freedom Philippines. 1 5 Table 2. U.S. approaches to ASG 46 Robinson...Implications for Future Defense Strategy.” 48 Anthony Measures, “What is Abu Sayyaf?” Centre on Religion and Geopolitics. May 17, 2016. Accessed

  13. Distribution of heavy metals in the coastal area of Abu Dhabi in the United Arab Emirates.

    Science.gov (United States)

    Al Rashdi, Saeed; Arabi, Alya A; Howari, Fares M; Siad, Abdi

    2015-08-15

    Fifty-seven sediment samples were collected from Abu Dhabi coastal area, United Arab Emirates (UAE). The concentrations of heavy metals including antimony, arsenic, barium, cadmium, cobalt, copper, mercury, lead, molybdenum, nickel and zinc were obtained using Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) and X-ray fluorescence. Heavy metal contaminations in Abu Dhabi had increased since 2004. Nevertheless, the enrichment factors, geoaccumulation indices and the pollution load index of 0.3 showed no pollution with any of the measured metals except arsenic. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Human brucellosis in the Emirate of Abu Dhabi, United Arab Emirates, 2010-2015.

    Science.gov (United States)

    Al Shehhi, Nawal; Aziz, Faisal; Al Hosani, Farida; Aden, Bashir; Blair, Iain

    2016-10-12

    Worldwide, human brucellosis remains an important and widespread infection. In the past, there were limited data on the occurrence of human brucellosis in the United Arab Emirates and the reported incidence appeared to be low compared with similar areas. In 2009, a new web-based infectious disease surveillance system was introduced in the Emirate of Abu Dhabi. This paper reports data from this new system on human brucellosis for the 6 years 2010 to 2015. A dataset was extracted for each case of human brucellosis reported to the notification system for the 6 year period January 2010 to December 2015. Annual brucellosis rates by age-group, gender, nationality and, geographical region were calculated and compared. A total of 480 cases of brucellosis were reported. The overall crude notification rate was 3 · 3 per 100,000 population but higher rates were seen in certain population subgroups notably expatriate males of working age in the Eastern Region (approximately 10 per 100,000) and UAE nationals of all ages and both genders in Abu Dhabi (between 4 -- 24 per 100,000). These findings reflect environmental and behavioral factors linked to occupation and leisure time activities associated with the large number of small non-commercial livestock farms in Abu Dhabi. Controlling human brucellosis in these circumstances will be challenging.

  15. The stratigraphic record of Khawr Al Maqta, Abu Dhabi, United Arab Emirates

    Science.gov (United States)

    Lokier, S. W.; Herrmann, S.

    2012-04-01

    Well-constrained modern depositional analogues are vital to the development of accurate geological reservoir models. The development of realistic hydrocarbon reservoir models requires the application of high-precision, well-constrained outcrop and sub-surface data sets with accurately-documented facies geometries and depositional sequence architectures. The Abu Dhabi coastline provides the best modern analogue for the study of ramp-style carbonate depositional facies akin to those observed in the sub-surface reservoirs of the United Arab Emirates (UAE). However, all previous studies have relied on temporally limited surface datasets. This study employed thirty five shallow subsurface cores spanning the width of the Khawr Al Maqta - the narrow shallow tidal channel that separates Abu Dhabi Island from the mainland. The cores were taken over a transect measuring 1.2 km in length by 50 m wide thus providing a high-resolution record of sub-surface facies geometries in a stratigraphically complex setting. Geometries in these Pleistocene to Holocene facies are complex with interdigitating, laterally heterogeneous carbonate, siliciclastic and evaporite units represented throughout the area of the study. Carbonate facies range from molluscan rudstones to marls and are all indicative of deposition in a shallow, relatively low energy marine setting akin to that seen in the environs of Abu Dhabi Island today. Texturally mature quartz sands occur as thin lenses and as thin cross bedded or laminated horizons up to twenty five centimetres thick. Glauconitic mudstones are common and locally exhibit evidence of rootlets and desiccation cracks. Evaporites are present in the form of gypsum occurring as isolated crystals and nodules or as massive chicken-wire units in excess of three metres thick. All of these textures are consistent with evaporite development in the shallow subsurface. Early, shallow-burial diagenesis has been important. Bioclasts are pervasively leached throughout

  16. The Abu Ghraib Scandal: Impact on the Army Profession and the Intelligence Process

    National Research Council Canada - National Science Library

    Bland, Dean

    2005-01-01

    .... Allegations of physical and emotional abuses by U.S. military personnel against Iraqi detainees in the Abu Ghraib prison shocked the world and led to calls for investigations, punishments, resignations, and war policy adjustments...

  17. A Comparative Analysis into U.S. Military Abuses at the My Lai Massacre and Abu Ghraib Prison Scandal

    Science.gov (United States)

    2015-06-01

    loneliness and depression .24 He also reveals the escalation of violence that took place, such as shooting stray dogs for sport.25 As mentioned above... YouTube video, 9:51, posted by “Ryan Plant,” December 1, 2012, https://www.youtube.com/watch?v=LDAd8i7dAWs. 24 Aiden Delgado, Sutras of Abu Ghraib...terrorist group of global reach has been 80 “Ghosts of Abu Ghraib,” YouTube video, 78:16, directed by

  18. Human Right Abuses of Prisoners at Abu Ghraib

    OpenAIRE

    Lisa D. Henry

    2017-01-01

    Abu Ghraib, located a few miles on the western end of Baghdad, was an infamous prison facility, during the reigns of Saddam Hussein. Thousands of inmates were held at one time in the facility. Inmates were subjected to executions and torture along with despicable living conditions. After U.S. intimated the collapse of the vile regime of Hussein in 2002-03, lootings followed. The prison facility was also a target of such mob attacks. This led to the facility’s already bare minimum fixtures des...

  19. United Arab Emirates- fall of $0.75/b of retroactive prices from Abu Dhabi for the month of february

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    The Abu Dhabi National Oil Company (Adnoc) announced a fall of $0.75/b of petroleum prices for sales executed in february. The production of the new deposit Neewat al-Ohalan, put in production in june 1995 is 7000 b/day. The production of the Mubarraz field is 20 000 b/day. The Abu Dhabi Onshore Oil Operating Company (Adco) has announced that all these projects have been realized in 1995. It is the first company of Abu Dhabi and its production capacity is one million of barrels by day. The contract for a refinery of 4.5 millions of tons /year at Mahmood Kot near Multan has been attributed to the Babcock King Wilkinson britain company and is expected for 2000. The project plans an extension of the pipeline, from Karachi to Multan, on 350 km towards Faisalabad and Lahore. (N.C.)

  20. A COMPARATIVE ASSESSMENT OF HOUSING DYNAMICS IN ABU DHABI AND DOHA

    Directory of Open Access Journals (Sweden)

    Hatem Ibrahim

    2016-11-01

    Full Text Available Abu Dhabi and Doha have evolved rapidly in the twentieth century due to the investment of oil and gas revenues. The fast economic growth resulted in an extensive period of urbanization. The various urban dynamics had a great impact with regards to new housing typologies during the last few decades. Doha’s housing market is studied in comparison with Abu Dhabi’s market considering their population growth rates, real estate market conditions, socio-cultural characteristics, and political approaches. The study is focused on the period from 2004 to 2013 where rapid urban development took place in both cities. The comparative assessment is based on three key aspects: housing typologies, housing distribution, in addition to housing supply and demand. The paper highlights that the urban growth in both cities is initiated via government investments, especially in the real estate market. This is reflected in the case of very similar housing dynamics in both cities. A gradual replacement of low-rise residential villas by high-rise residential towers (apartments/ penthouses is currently observed in both cities.

  1. Abu Ghraib and the War against Terror - a case against Donald Rumsfeld

    NARCIS (Netherlands)

    Smeulers, A.L.; Niekerk, S.

    2009-01-01

    The pictures of the inhuman and abusive treatment of Iraqi prisoners at the Abu Ghraib prison shocked the world. The authors of this contribution will take a criminological approach to the crimes committed and will show-by using an analytical framework used by organizational criminologists-that the

  2. Pemurnian Silika Pada Abu Layang Dari Pembangkit Listrik Di Paiton (PT YTL) Dengan Pelarutan Asam Klorida Dan Aqua Regia

    OpenAIRE

    Anggia, Denida Mega; Suprapto, Suprapto

    2016-01-01

    Penelitian mengenai pemurnian silika melalui pelarutan menggunakan asam klorida (HCl) dan aqua regia pada abu layang yang berasal dari PT YTL, Paiton, telah dilakukan.Parameter yang digunakan dalam penelitian ini adalah konsentrasi asam dan waktu pelarutan HCl. Pengaruh pelarutan unsur Fe, Ca, dan Al dari sampel juga diteliti.Dari hasil XRD abu layang, terkandung mineral quartz, mullite, hematite dan kalsium oksida. Kondisi paling baik pada saat pelarutan sampel adalah menggunakan pelarutan a...

  3. Variation by Gender in Abu Dhabi High School Students' Interests in Physics

    Science.gov (United States)

    Badri, Masood; Mazroui, Karima Al; Al Rashedi, Asma; Yang, Guang

    2016-04-01

    Abu Dhabi high school students' interest in physics in different contexts was investigated with a survey conducted in connection with the international project, The Relevance of Science Education (ROSE). The sample consisted of 2248 students in public and private schools. Means of most items that belong to the school physics context for both girls and boys were below the score of (3.0). The most interesting topics for both genders were connected with fantasy items. The least interesting items (particularly for girls) were connected with artifacts and technological processes. Girls assigned the highest scores for "why we dream" and "life and death." Boys assigned the highest scores for "inventions and discoveries" and "life outside of earth." The main message of the study is that new curricular approaches and textbooks can be developed through combining technological and human contexts. The implications for curriculum development, teacher professional development programs, and other education strategies in Abu Dhabi are discussed in light of the ROSE survey.

  4. ADSORPSI Pb2+ DALAM LIMBAH CAIR ARTIFISIAL MENGGUNAKAN SISTEM ADSORPSI KOLOM DENGAN BAHAN ISIAN ABU LAYANG BATUBARA SERBUK DAN GRANULAR

    Directory of Open Access Journals (Sweden)

    Widi Astuti

    2015-07-01

    Full Text Available Batubara  merupakan  salah  satu  sumber energi  alternatif  yang murah. Oleh karena itu,  penggunaan  batubara  di  Indonesia meningkat pesat  setiap  tahunnya. Penggunaan batubara  ini  menghasilkan  limbah  yang  dapat mencemari lingkungan baik limbah gas  seperti   CO2, NOX,  CO,  SO2,  hidrokarbon  maupun  limbah  padat  yang berupa abu  layang dan  abu  dasar. Abu  layang  mengandung SiO2, Al2O3,  dan sisa karbon yang tidak terbakar sehingga potensial digunakan sebagai adsorben. Pada penelitian ini, kemampuan adsorpsi abu layang ditingkatkan melalui aktivasi termal dan diuji untuk menjerap ion Pb2+ dalam limbah cair artifisial. Adsorpsi dilakukan pada sistem kolom yang berlangsung kontinyu menggunakan bahan isian abu layang teraktivasi, dalam bentuk serbuk dan granular, pada laju alir influen yang bervariasi. Hasilnya, laju alir mempengaruhi nilai kapasitas (qo, konstanta thomas (KtH dan waktu breakthrough.Kata Kunci : Pb2+ , adsorpsi, abu layang, breakthrough Coal is one of the inexpensive alternative energy. Therefore, the usage of coal in indonesia has been increased every year. It produces waste that can pollute the environment including gases waste such as CO2, NOX, CO, SO2, hydrocarbons and solid waste including fly ash and bottom ash. Coal fly ash is composed of  SiO2, Al2O3 and unburned carbon that enables it to act as a potential adsorbent. In this research, the adsorption capasity has increased by thermal activation and used to adsorp Pb2+ ion in wastewater.  The adsorption was carried out in packed column contains powder and granular activated fly ash. In the system, flow rate was varied.  The results show that flow rate influences adsorption capacity, Thomas constant and breakthrough time.Keywords: Pb2+, adsorption, coal fly ash, breakthrough

  5. Mapping b-values beneath Abu Dabbab from June to August 2004 earthquake

    Directory of Open Access Journals (Sweden)

    I.F. Abu El-Nader

    2016-12-01

    Full Text Available Abu Dabbab area is considered as one of the most active earthquake sources in Egypt. It is defined by its swarm type activity, and complicated stress pattern. This study was conducted to evaluate the two and three dimensional spatial distribution of b-value at Abu Dabbab area (Margin of the northern Red Sea Rift, Egypt. The gridding technique of Wiemer and Wyss (1997 was used to compute b-value using ZMAP software. The b-value is calculated from a catalog consisting of 850 well-located earthquakes, which were recorded from 1st June to August 2004, using the maximum likelihood method. These earthquakes were recorded by temporary digital seismic network, with magnitudes ranging from −1 to 3.4 ML. It is important to mention that the variations of b-value with time cannot be easily detected for a short period. Hence, this study has been carried out to examine the variations of b-value in space. The computed b-value in the Abu Dabbab area does not follow a uniform distribution. A small volume of anomalously high b-value (b > 1.8 exists in the central part of the area at a depth between 6 and 9 km. This seems to agree with the reported low velocity value derived from previous P-wave travel time tomography studies (Hosny et al., 2009 and the low Q value (Abdel-Fattah et al., 2008. The existence of an anomalously high b-value region may be attributed to the presence of a magma reservoir or dyke zone beneath the northern Red Sea Rift that causes an intensively heterogeneous fractured crust or unusually high pore pressure.

  6. Health insurance reform and the development of health insurance plans: the case of the Emirate of Abu Dhabi, UAE.

    Science.gov (United States)

    Hamidi, Samer; Shaban, Sami; Mahate, Ashraf A; Younis, Mustafa Z

    2014-01-01

    The Emirate of Abu Dhabi has taken concrete steps to reform health insurance by improving the access to health providers as well as freedom of choice. The growing cost of health care and the impact of the global financial crisis have meant that countries are no longer able to solely bear the cost. As a result many countries have sought to overhaul their health care system so as to share the burden of provision with the private sector whether it is health care plan providers or employers. This article explores and discusses how the policy issues inherent in private health care schemes have been dealt with by the Emirate of Abu Dhabi. Data was collected in early 2013 on health care plans in Abu Dhabi from government sources. The Abu Dhabi model has private sector involvement but the government sets prices and benefits. The Abu Dhabi model adequately deals with the problem of adverse selection through making insurance coverage a mandatory requirement. There are issues with moral hazards, which are a combination of individual and medical practitioner behavior that might affect the efficiency of the system. Over time there is a general increase in the usage of medical services, which may be reflective of greater awareness of the policy and its benefits as well as lifestyle change. Although the current health care system level of usage is adequate for the current population, as the level of usage increases, the government may face a financial burden. Therefore, the government needs to place safeguards in order to limit its exposure. The market for medical treatment needs to be made more competitive to reduce monopolistic behavior. The government needs to make individuals aware of a healthier lifestyle and encourage precautionary actions.

  7. Setting Up an ePathology Service at Cleveland Clinic Abu Dhabi: Joint Collaboration With Cleveland Clinic, United States.

    Science.gov (United States)

    Nahal, Ayoub; Batac, Crystal Mildred O; Slaw, Renee J; Bauer, Thomas W

    2018-04-24

    - The production of whole slide images is the most advanced form of digital pathology, in which a high-resolution digital scanner is used to rapidly scan glass microscope slides and produce a computer-generated whole slide image that can be saved, stored in a network-attached storage device, and accessed through slide management software within the hospital domain and remotely by authorized users. Digital transformation of glass slides has revolutionized the practice of anatomic pathology by facilitating and expediting consultative services, improving clinical workflow, and becoming an indispensable tool in education and research. - To highlight the institutional need of Cleveland Clinic Abu Dhabi (Abu Dhabi, United Arab Emirates) and the cultural background for obtaining the United Arab Emirates' first comprehensive digital pathology program; to describe a multiphase road map for achieving full implementation of this platform; and to describe the system's clinical applications and its future potential growth. - At Cleveland Clinic Abu Dhabi, we prioritized our efforts to initiate digital consultations (eConsultations) and digital immunohistochemistry services (eIHC) with Cleveland Clinic Laboratories (Cleveland, Ohio). After this, we established an internal archiving system together with a subspecialty-based, organ-specific digital library of pathologic diseases. - We describe the strategic adoption and implementation of digital pathology into the clinical workflow of the pathology and laboratory medicine institute of Cleveland Clinic Abu Dhabi, and we highlight its impact on clinical operations, educational activities, and patient care.

  8. Analysis of Modern Elements in Works of Abu Turab Khosravi

    Directory of Open Access Journals (Sweden)

    Hosniyeh Nejatzadeh Eidgahi

    2017-06-01

    Full Text Available Contemplation on the theoretical foundations of modern fiction and modern texts denotes the fact that some of these texts highlight the new features of trends of modernism in literature closely related to the theme and motif including the inherent time and abstract thought. So far only some modernist elements were analyzed theoretically, while their competence and highlight is of important in modernist narratives that will be discussed in the current research. Features such as highlighted concepts of dying, deabsolutism and imbalance. The collections Divane Somenat, Havieyeh and Ketab-e Viran have the highest frequency in the use of the above components. The contemplation on the works by Abu Turab Khosravi from the perspective of characteristics listed as well as a few other basic components is a clear way and representation of his stories deep structure for the audience. The current paper modernist narratives are analytical-descriptive and in addition to introducing and analyzing each component of the narrative, one or more concrete example is given. The results show Abu Turab Khosravi is a technic-oriented writer and modernist features of delicate relationship with the fiction theme are hidden in narratives requiring to be explored in this context.

  9. Variation by Gender in Abu Dhabi High School Students' Interests in Physics

    Science.gov (United States)

    Badri, Masood; Mazroui, Karima Al; Al Rashedi, Asma; Yang, Guang

    2016-01-01

    Abu Dhabi high school students' interest in physics in different contexts was investigated with a survey conducted in connection with the international project, The Relevance of Science Education (ROSE). The sample consisted of 2248 students in public and private schools. Means of most items that belong to the school physics context for both girls…

  10. Geological heritage under strong urbanization pressure: El-Mokattam and Abu Roash as examples from Cairo, Egypt

    Science.gov (United States)

    AbdelMaksoud, Kholoud M.; Al-Metwaly, Wael M.; Ruban, Dmitry A.; Yashalova, Natalia N.

    2018-05-01

    Urban geological heritage is prone to anthropogenic pressure linked to urbanization. In order to understand the necessity of conservation of such a heritage located in two areas of Cairo (Egypt), namely El-Mokattam and Abu Roash, their assessment is undertaken. It is established that the both areas possess geological heritage. As much as five types of the latter are represented in each of them. The most important in El-Mokattam is geomorphological type (the Mokattam Mountain itself), and the most important in Abu Roash are palaeogeographical (facies and palaeoecosystems) and structural (outcrop-scale fold and faults) types. In the both areas, the geological heritage is destroyed because of rapid and often uncontrolled (even illegal) urbanization. According to the results of the satellite images interpretation, the urban area has grown by 1.4 times in El-Mokattam and 3.4 times in Abu Roash during the period of 2000-2017 when many unique objects were damaged and destroyed. Some aesthetic properties have been also lost, which has decreased the important of these objects to tourists, as well as many students and researchers. Assigning official protected status and possible geopark creation can facilitate efficient conservation of the urban geological heritage of Cairo.

  11. "Where Is the Love?": The Ethics of Empathy in Abu Ghraib

    Science.gov (United States)

    Sturgeon, Elizabeth M.

    2007-01-01

    Abu Ghraib. The name conjures horrifying images of abuse, torture, and man's inhumanity to man. In one photograph, a pyramid of naked detainees huddles outside a jail cell; in another, a soldier holds the end of a dog leash which is attached at the neck to a prostrate prisoner; in another, a soldier gives the thumbs-up sign in front of a line of…

  12. Molecular adjuvants based on nonpyrogenic lipophilic derivatives of norAbuMDP/GMDP formulated in nanoliposomes: stimulation of innate and adaptive immunity.

    Science.gov (United States)

    Knotigová, Pavlína Turánek; Zyka, Daniel; Mašek, Josef; Kovalová, Anna; Křupka, Michal; Bartheldyová, Eliška; Kulich, Pavel; Koudelka, Štěpán; Lukáč, Róbert; Kauerová, Zuzana; Vacek, Antonín; Horynová, Milada Stuchlová; Kozubík, Alois; Miller, Andrew D; Fekete, Ladislav; Kratochvílová, Irena; Ježek, Jan; Ledvina, Miroslav; Raška, Milan; Turánek, Jaroslav

    2015-04-01

    The aim of this work was to demonstrate an immunostimulatory and adjuvant effect of new apyrogenic lipophilic derivatives of norAbuMDP and norAbuGMDP formulated in nanoliposomes. Nanoliposomes and metallochelating nanoliposomes were prepared by lipid film hydration and extrusion methods. The structure of the liposomal formulation was studied by electron microscopy, AF microscopy, and dynamic light scattering. Sublethal and lethal γ-irradiation mice models were used to demonstrate stimulation of innate immune system. Recombinant Hsp90 antigen (Candida albicans) bound onto metallochelating nanoliposomes was used for immunisation of mice to demonstrate adjuvant activities of tested compounds. Safety and stimulation of innate and adaptive immunity were demonstrated on rabbits and mice. The liposomal formulation of norAbuMDP/GMDP was apyrogenic in rabbit test and lacking any side effect in vivo. Recovery of bone marrow after sublethal γ-irradiation as well as increased survival of mice after lethal irradiation was demonstrated. Enhancement of specific immune response was demonstrated for some derivatives incorporated in metallochelating nanoliposomes with recombinant Hsp90 protein antigen. Liposomal formulations of new lipophilic derivatives of norAbuMDP/GMDP proved themselves as promising adjuvants for recombinant vaccines as well as immunomodulators for stimulation of innate immunity and bone-marrow recovery after chemo/radio therapy of cancer.

  13. Abu Dhabi and Dubai: Economic development as in Arabian Nights?

    OpenAIRE

    Benner, Maximilian

    2011-01-01

    The development of Abu Dhabi and Dubai during past years seems breathtaking. Both emirates pursue a strategy of diversifying their economic structure and thus of becoming less dependent on oil and gas. The obvious goal is to secure their prosperity for an era beyond oil. Diversification is a relevant strategic imperative for other resource-rich developing countries, too. In view of the current transformation processes in Arab countries the question whether differing strategies of the two emir...

  14. Some dared call it torture: cultural resonance, Abu Ghraib, and a selectively echoing press

    NARCIS (Netherlands)

    Rowling, C.M.; Jones, T.M.; Sheets, P.

    2011-01-01

    This study draws upon research on "indexing" and "cascading activation" to explore U.S. political and news discourse surrounding the Abu Ghraib prison scandal. Specifically, we systematically analyze White House, military, congressional, and news messages. In so doing, we incorporate scholarship on

  15. Branding, legitimation and the power of museums: The case of the Louvre Abu Dhabi

    Directory of Open Access Journals (Sweden)

    Btihaj Ajana

    2015-07-01

    Full Text Available Museums and cultural developments are on the rise in the Gulf region. The United Arab Emirates is home to some of the most ambitious and extravagant museum projects in the world. In this article, I consider the example of the Louvre Abu Dhabi, exploring some of its underlying dynamics and context. I focus mainly on the relationship between branding and legitimation while placing my analysis within a wider critical debate, which includes discussions on the link between museums and identity, the legitimizing role of architecture, and the various contentious concerns and controversies surrounding the Louvre Abu Dhabi project. I conclude that the United Arab Emirates and other neighbouring countries have an excellent opportunity for innovation in the cultural field if they are willing to critically and ethically found their cultural developments on an ethos of inclusivity, openness, experimentation, non-exploitation and curatorial courage.

  16. Application of a precipitation method for uranium recovery from Abu-Zaabal phosphoric acid plant, egypt

    International Nuclear Information System (INIS)

    El-Hazek, N.M.T.; Hussein, E.M.

    1997-01-01

    Current industrial recovery of uranium from 30% phosphoric acid-produced by the dihydrate process-is based on solvent extraction method. Uranium recovery from concentrated phosphoric acid (45-52% P 2 O 5 ) produced by evaporation of the 30% acid or directly produced by the hemihydrate process, by solvent extraction is difficult to apply in practice. In addition to possible contamination of the acid by the organic solvents and/or their deterioration. This paper investigates the possibility of applying a precipitation method (Weterings and Janssen, 1985) for uranium recovery from both low (28% P 2 O 2 ) and high (48% P 2 O 5 ) concentration phosphoric acids produced by abu-Zaabal phosphoric acid plant (abu-Zaabal fertilizers and chemicals Co., Egypt). The 28% acid produced by H 2 SO 4 dihydrate method and the 48% acid produced by evaporation of the 28% acid

  17. Renewable energy policy options for Abu Dhabi: Drivers and barriers

    International Nuclear Information System (INIS)

    Mezher, Toufic; Dawelbait, Gihan; Abbas, Zeina

    2012-01-01

    Climate change and fossil fuel depletion are the main drivers for the recent focus on Renewable Energy (RE) resources. However, since the high cost of RE technologies is the main obstacle facing the diffusion of RE power generation, economic and political intervention is inevitable. In the United Arab Emirates (UAE) population and economic growth are the main causes of a sharp increase of energy demand. Two key related factors highlight the need to establish a RE sector: first the UAE has one of the highest carbon footprint in the world and second, the rate of depletion of its main energy generation resource – fossil fuel. In this study, we present a review of overall policies in sixty-one countries, focusing on their efforts to adopt RE resources in the power sector, and on their implementation of fundamental policies implemented. Furthermore, we investigate the applicability to Abu Dhabi UAE of the main RE policies implemented worldwide. As a result of our analysis, we recommend the implementation of a mixed policy of Feed-in-Tariff (FIT) and the Quota system for RE electricity generation in order for the UAE to meet its 7% target by 2020. - Highlights: ► Comprehensive review of renewable energy policy mechanisms. ► Summarizes the renewable energy policy adoptions, targets, and installed capacity in many countries. ► Gives recommendations on renewable energy policy options for Abu Dhabi, an oil rich country.

  18. Recent benthic foraminifera assemblages from mangrove swamp and channels of Abu Dhabi (UAE)

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.; Odeh, Weaam A. S. Al; Paul, Andreas; Song, Jianfeng; Freeman, Mark; Michel, Françoise

    2017-04-01

    Zonation of Recent mangrove environments can be defined using benthic foraminifera, however, little is known about foraminifera from mangrove environments of the Persian/Arabian Gulf. The objective of this study is to produce a detailed micropaleontological and sedimentological analysis to identify foraminiferal associations from mangrove swamps and channels located on the eastern side of Abu Dhabi Island (UAE). Detailed sediment sampling collection in mangal environments of Eastern Abu Dhabi was carried out to assess the distribution of benthic foraminifera in different sedimentary facies in the mangal and in the surrounding natural environments of the upper and lower intertidal area (mud flats and channels). A 100 m transect across a natural channel in a mangal on the eastern side of Abu Dhabi Island was sampled in detail for sedimentological and foraminiferal analysis. Forty-seven samples were collected at 2 meter intervals along the transect in a number of different sedimentary facies including; fine sediment in areas exposed during low tide and close to mangrove trees (Avicennia marina), fine sediment rich in leaf material, coarse sediment in channels, and coarse sediments with a shell lag. At each sampling location environmental parameters were recorded, including water depth, salinity, temperature and pH. Samples collected for foraminiferal analysis were stained in rose Bengal in order to identify living specimens. Samples collected on the mud flat at the margin of the channel show a living foraminiferal assemblage characterised by abundant foraminifera belonging to the genera Ammonia, Elphidium, Cribroelphidium, Triloculina, Quinqueloculina, Sigmoilinita, Spiroloculina, Peneroplis and Spirolina. Samples collected in the lower (wet) intertidal area close to Avicennia marina roots, presented a low-diversity assemblage mostly comprising small-sized opportunistic foraminifera of the genera Ammonia and Cribroelphidium along with rare Triloculina and

  19. Preliminary crustal deformation model deduced from GPS and earthquakes’ data at Abu-Dabbab area, Eastern Desert, Egypt

    Directory of Open Access Journals (Sweden)

    Abdel-Monem S. Mohamed

    2013-06-01

    From the seismic tomography study, the 3D Vp and Vp/Vs crustal models indicate high Vp/Vs values forms an elongated anomaly, in the central part of the study area, that extends from a depth of 12 km to about 1–2 km of depth is obtained. By using this crustal model in relocations all seismicity informed that most of the seismicity strongly tend to occur in a cluster manner exactly above the southern part of the study area. Based on the conducted source mechanism study, it is noticed that shallow earthquakes are associated by a high CLVD ratio (up to 40%. Furthermore, initiation of a high level seismic activity, without a large seismic main shock is observed in the Abu-Dabbab area. The distribution of micro-earthquakes tends to align in an ENE–WSW direction marking a zone of activity verse the Red Sea. The nucleation of the seismic activity beneath the southern part of the Abu-Dabbab crust is more consistent with the obtained crustal deformation result by increasing the crustal movement in the south part than the northern part. Then, based on the obtained results of the above mentioned studies; seismic tomography; source mechanisms, and crustal deformation we conclude that these seismic activities that are associated by crustal deformation are owing to some magma activity beneath the crust of the Abu-Dabbab area.

  20. STS-45 Earth observation of the Persian Gulf and the island of Abu Ali

    Science.gov (United States)

    1992-01-01

    STS-45 Earth observation taken aboard Atlantis, Orbiter Vehicle (OV) 104, is of the northern reaches of the Persian Gulf with the sunglint pattern centered on the Saudi Arabian island of Abu Ali. Bright features along the coast are thought to be deposits of oil, released from a terminal offshore of Kuwait during the recent Persian Gulf War. Further up the coast, in Kuwait, the black, oil-soaked desert surrounding the site of the oil well fires is clearly visible. View was taken from an altitude of 160 nautical miles with OV-104 located at 28 degrees north and 52.8 degrees east. During the STS-45 mission, an international survey team focused on oil contamination of the shallow-water habitants in the area north of Abu Ali Island. Crewmembers contacted the NOAA survey vessel, the R/V Mt. Mitchell, several times and photographed water color and sunglint within the study area and throughout the entire Persian Gulf. These photographic data are expected to aid the Persian Gulf researchers in

  1. The Westernization of Arab Pedagogies: Abu Dhabi Attempts to Move towards a Knowledge Economy

    Science.gov (United States)

    Chrystall, Steve

    2014-01-01

    As the oil reserves in the United Arab Emirates (UAE) are forecast to become depleted over the next 50 to 150 years, the emirate of Abu Dhabi has set a vision to develop a knowledge economy in order to develop alternative sources of revenue in areas such as tourism, alternative energy and innovative business enterprises. Reformation of its…

  2. Structural interpretation of seismic data of Abu Rudeis-Sidri area, Northern Central Gulf of Suez, Egypt

    Directory of Open Access Journals (Sweden)

    Hesham Shaker Zahra

    2016-12-01

    Full Text Available The 2D and 3D seismic data are interpreted to evaluate the subsurface geologic structures in the Abu Rudeis-Sidri area that occupy the northern central part of the Gulf of Suez. The 2D seismic data are used for determination of the structural configurations and the tectonic features which is analyzed through the study of interpretation with the available geologic data, in which the geo-seismic depth maps for the main interesting tops (Kareem, Nukhul, Matulla, Raha and Nubia Formations are represented. Such maps reflect that, the Miocene structure of Abu Rudeis-Sidri area is an asymmetrical NW-SE trending anticlinal feature dissected by a set of NW-SE fault system (clysmic. Added, the Pre-Miocene structure of the studied area is very complex, where the area is of NE dip and affected by severe faulting through varying stratigraphic levels.

  3. A Review of the Water and Energy Sectors and the Use of a Nexus Approach in Abu Dhabi

    Science.gov (United States)

    Paul, Parneet; Al Tenaiji, Ameena Kulaib; Braimah, Nuhu

    2016-01-01

    Rapid population increase coupled with urbanization and industrialization has resulted in shortages of water in the Middle East. This situation is further exacerbated by global climate change due to greenhouse gas emissions. Recent research advocates that solutions to the global water security and scarcity crisis must involve water–energy nexus approaches. This means adopting policies and strategies that harmonize these inter-related sectors to minimize environmental impact while maximizing human benefit. In the case of Abu Dhabi, when designing and locating oil/gas refineries and associated power generation facilities, previous relevant decisions were based on simple economic and geographical grounds, such as nearness to oil rigs, pipelines, existing industries and port facilities, etc. The subsequent design and location of water abstraction and treatment works operated by the waste heat from these refining and/or power generation processes was catered for as an afterthought, meaning that there is now a mismatch between the water and energy supplies and demands. This review study was carried out to show how Abu Dhabi is trying now to integrate its water–energy sectors using a nexus approach so that future water/power infrastructure is designed optimally and operated in harmony, especially in regard to future demand. Based upon this review work, some recommendations are made for designers and policy makers alike to bolster the nexus approach that Abu Dhabi is pursuing. PMID:27023583

  4. A Review of the Water and Energy Sectors and the Use of a Nexus Approach in Abu Dhabi.

    Science.gov (United States)

    Paul, Parneet; Al Tenaiji, Ameena Kulaib; Braimah, Nuhu

    2016-03-25

    Rapid population increase coupled with urbanization and industrialization has resulted in shortages of water in the Middle East. This situation is further exacerbated by global climate change due to greenhouse gas emissions. Recent research advocates that solutions to the global water security and scarcity crisis must involve water-energy nexus approaches. This means adopting policies and strategies that harmonize these inter-related sectors to minimize environmental impact while maximizing human benefit. In the case of Abu Dhabi, when designing and locating oil/gas refineries and associated power generation facilities, previous relevant decisions were based on simple economic and geographical grounds, such as nearness to oil rigs, pipelines, existing industries and port facilities, etc. The subsequent design and location of water abstraction and treatment works operated by the waste heat from these refining and/or power generation processes was catered for as an afterthought, meaning that there is now a mismatch between the water and energy supplies and demands. This review study was carried out to show how Abu Dhabi is trying now to integrate its water-energy sectors using a nexus approach so that future water/power infrastructure is designed optimally and operated in harmony, especially in regard to future demand. Based upon this review work, some recommendations are made for designers and policy makers alike to bolster the nexus approach that Abu Dhabi is pursuing.

  5. Did the contagion effect exist? Evidence from Abu Dhabi, Jordan and America

    OpenAIRE

    Ho, Liang-Chun; Huang, Chia-Hsing

    2014-01-01

    This article aims to test the contagion effect between the stock markets of Abu Dhabi, Jordan and America. The Lagrange multiplier (LM) principle for causality in variance test is used in this study. Four American stock indexes, Dow Jones Industrial Average, NASDAQ Composite, RUSSELL 2000, and PHLX Semiconductor Sector Index, are in this study. The testing results of the four major American stock price indexes and the Jordan stock index (Amman) are significant. The testing results of the f...

  6. The operation, products and promotion of waterpipe businesses in New York City, Abu Dhabi and Dubai.

    Science.gov (United States)

    Joudrey, P J; Jasie, K A; Pykalo, L; Singer, S T; Woodin, M B; Sherman, S

    2016-07-10

    We evaluated the customers, operations, products and advertising of these businesses to explore the unique policy challenges created by the suppliers of waterpipes. We completed a cross-sectional survey consisting of structured site observations and in-person interviews of businesses in New York City, Abu Dhabi and Dubai identified using Google, Yelp, Timeout Dubai and Timeout Abu Dhabi and neighbourhood visits in 2014. Regular customers made up 59% of customers. Franchises or chains were 28% of businesses. Waterpipes made up 39% of sales with 87% of businesses offering food within their menu. Flavoured tobacco made up 94% of sales. Discounts were offered by 47% of businesses and 94% of businesses used advertising, often through social media. The market consists of largely independent businesses, with a large regular customer base, frequently offering diversified services beyond waterpipes. These businesses advertise using both traditional and social media. The economics of waterpipe businesses is very different from the economics of cigarettes, and unique regulatory strategies are needed to control this epidemic.

  7. Poisoned social climate, collective responsibility, and the abuse at Abu Ghraib--Or, the establishment of "rule that is lack of rule".

    Science.gov (United States)

    Mestrovic, Stjepan G; Romero, Rachel

    2012-01-01

    The authors draw upon the experiences of one of the co-authors as an expert witness in sociology for mitigation at three of the courts-martial pertaining to the abuse at Abu Ghraib that were held at Ft. Hood, Texas in the year 2005 (for Javal Davis, Sabrina Harman, and Lynndie England). In addition, this paper is based upon the thousands of pages of affidavits, testimony, and U.S. Government reports concerning Abu Ghraib. These internal government reports, as well as the Levin-McCain report, point to collective responsibility and the responsibility of individuals high in the chain of command for establishing unlawful techniques. We review the shortcomings of a purely psychological approach for understanding the abuse, and turn to Durkheim's original understanding of anomie as a state of social derangement or rule by lack of rule to introduce the ideas of the social origins of and social responsibility for the abuse. We conclude with sociological suggestions for reforming some of the legal, medical, psychiatric, and other professional complicity in the abuse at Abu Ghraib. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Natural Radioactivity in Abu-Tartor Phosphate Deposits and the Surrounding Region, New Valley, Egypt

    International Nuclear Information System (INIS)

    Khater, A.E.; Higgy, R.H.; Pimpl, M.

    1999-01-01

    Abu-Tartor phosphate mine. New Valley district, is one of the biggest phosphate mines in Egypt which will start full production soon. The planned ore rocks (24.8%P 2 O 5 ) annual production is 4 million tons. The aim of this study is to estimate the natural radioactivity levels in Abu-Tartor phosphate deposits and the surrounding region. The environmental radioactivity levels in the surrounding region will be considered as pre-operational levels which are essential to determine the radiological impacts of phosphate mining later on. Phosphate samples (ore rocks, wet rocks and beneficiation wastes) and environmental samples (soil, water and plant)were collected. The specific activities of Ra-226 (U-238) series, Th-232 series and K-40 were measured using gamma-ray spectrometry based on Hyper pure Germanium detectors. The specific activities of uranium isotopes (U-238, U-235 and U-234) were measured using alpha spectrometry based on surface barrier detectors after radiochemical separation. The specific activity of Pb-210 was measured using low background proportional gas counting system after radiochemical separation . The results were discussed and compared with national and international values

  9. Age Specific Cytological Abnormalities in Women Screened for Cervical Cancer in the Emirate of Abu Dhabi.

    Science.gov (United States)

    Al Zaabi, Muna; Al Muqbali, Shaikha; Al Sayadi, Thekra; Al Ameeri, Suhaila; Coetsee, Karin; Balayah, Zuhur; Ortashi, Osman

    2015-01-01

    Cervical cancer is the second most common cancer in women worldwide, with about 500,000 new cases and 270,000 deaths each year. Globally, it is estimated that over one million women currently have cervical cancer, most of whom have not been diagnosed, or have no access to treatment that could cure them or prolong their lives. In the United Arab Emirates (UAE) cervical cancer is the third most common cancer in women. A population-based cross-sectional retrospective survey of cervical smear abnormalities was conducted in the Emirate of Abu Dhabi, UAE, from January 2013 to December 2013 by collecting consecutive liquid-based cytology samples from the Department of Pathology at the SKMC Hospital in Abu Dhabi city. The total number of women screened for cervical cancer for the year 2013 at SKMC was 4,593, with 225 (4.89%) abnormal smears. The majority of the abnormal smear results were atypical squamous cells of undetermined significance (ASCUS) 114 (2.48%). This study showed 60% increase in the rate of abnormal cervical smears in the UAE over the last 10 years. In this study the highest incidence of high grade abnormalities were seen in women above the age of 61 years (1.73%), this might be due to the fact that this group of women missed the chance of screening of cervical cancer earlier in their lives or could be explained by the well-known second peak of HPV infection seen in many prevalence studies. We conclude that the rate of abnormal cervical smear in the screened Abu Dhabi women is not different from the rate in developed countries. A notable increase in both low and high grade abnormalities has occurred within the last decade.

  10. Bio leaching of Uranium - bearing material from Abu Thor area, West Central Sinai, Egypt for recovering uranium

    International Nuclear Information System (INIS)

    Abd El Wahab, G.M.; Amin, M.M.; Aita, S.K.

    2012-01-01

    A uranium-bearing material was recorded within the Intra-Carboniferous Paleokarst Profile of Um-Bogma Formation at Abu Thor area, West Central Sinai, Egypt. The present paper is concerned with the bio leaching of U and Cu using Aspergillus Niger (A. Niger) followed their proper recovery. The working Abu Thor representative sample assays 0.22% U as the element of interest as well as up to 25% CuO beside the other rock constituents SiO 2 (33%), Al 2 O 3 (10.4%) and CaO(8.5%). The effective bio leaching of U and Cu from Abu Thor ore sample using A.Niger was performed at the following optimum conditions: an incubation time of 6 days, sample/ liquid (S/L) ratio of 1/10, ph value of 1 and a temperature of 60 degree C. The prepared bio leach liquor assays 0.19 g/l of U and 15.8 g/l of Cu with leaching efficiencies of 97% and 79%, respectively. Uranium was recovered using 25% TBP in kerosene at O/A ratio of 1/1 and contact time of 5 min with achieved extraction efficiency of 96%. However the stripping of U was conducted by using 8% Na 2 CO 3 at A/O ratio of 1/1 and contact time of 5 min with stripping efficiency reached 99%. On the other hand, Cu was directly precipitated as CuS using the freshly released H 2 S gas with the addition of solid Na 2 S. The optimum precipitation conditions were S/L ratio of 1/100, ph 1.5 and room temperature where the precipitation efficiency of Cu achieved 99%

  11. Sedimentology and Reservoir Characteristics of Early Cretaceous Fluvio-Deltaic and Lacustrine Deposits, Upper Abu Gabra Formation, Sufyan Sub-basin, Muglad Rift Basin, Sudan

    Science.gov (United States)

    Yassin, Mohamed; Abdullatif, Osman; Hariri, Mustafa

    2017-04-01

    Sufyan Sub-basin is an East-West trending Sub-basin located in the northwestern part of the Muglad Basin (Sudan), in the eastern extension of the West and Central Africa Rift System (WCARS). The Early Cretaceous Abu Gabra Formation considered as the main source rock in the Muglad Basin. In Sufyan Sub-basin the Early Cretaceous Upper Abu Gabra Formation is the main oil-producing reservoir. It is dominated by sandstone and shales deposited in fluvio-deltaic and lacustrine environment during the first rift cycle in the basin. Depositional and post-depositional processes highly influenced the reservoir quality and architecture. This study investigates different scales of reservoir heterogeneities from macro to micro scale. Subsurface facies analysis was analyzed based on the description of six conventional cores from two wells. Approaches include well log analysis, thin sections and scanning electron microscope (SEM) investigations, grain-size, and X-ray diffraction (XRD) analysis of the Abu Gabra sandstone. The cores and well logs analyses revealed six lithofacies representing fluvio-deltaic and lacustrine depositional environment. The sandstone is medium to coarse-grained, poorly to moderately sorted and sub-angular to subrounded, Sub-feldspathic arenite to quartz arenite. On macro-scale, reservoir quality varies within Abu Gabra reservoir where it shows progressive coarsening upward tendencies with different degrees of connectivity. The upper part of the reservoir showed well connected and amalgamated sandstone bodies, the middle to lower parts, however, have moderate to low sandstone bodies' connectivity and amalgamation. On micro-scale, sandstone reservoir quality is directly affected by textures and diagenesis.The XRD and SEM analyses show that kaolinite and chlorite clay are the common clay minerals in the studied samples. Clay matrix and quartz overgrowth have significantly reduced the reservoir porosity and permeability, while the dissolution of feldspars

  12. Elemen Kebangsawanan dalam Pemilihan Pemimpin: Analisis Kontekstual Pemilihan Saidina Abu Bakr, Muawiyyah serta Kesultanan Melayu

    OpenAIRE

    Mohd Haidhar Kamarzaman; Norakmal Azraf Awaluddin; Muhammad Akmal Othoman; Yusri Mohamad Ramli

    2013-01-01

    Pemilihan pemimpin negara dalam Islam merupakan tugas yang berat ini selaras dengan kepentingannya dilihat sebagai pengganti Rasulullah (s.a.w) iaitu menyebarkan Islam dan mentadbir kelangsungan Islam. Namun yang menjadi fokus kepada penulisan ini adalah faktor kebangsawanan dalam pelantikan pemimpin dalam Islam. Kajian ini memfokuskan kepada sejarah bagaimana elemen kebangsawanan kaum Quraisy bagi Saidina Abu Bakar r.a menjadi faktor yang berpengaruh dalam pelantikan beliau sebagai khalifah ...

  13. Solostamenides paucitesticulatus n. sp. (Monogenoidea: Mazocraeidea: Microcotylidae) from the freshwater mullet Liza abu (Heckel) (Mugiliformes: Mugilidae) from Atatürk Reservoir on the Euphrates River in southern Turkey.

    Science.gov (United States)

    Kritsky, Delane C; Öktener, Ahmet

    2015-06-01

    Solostamenides paucitesticulatus n. sp. (Monogenoidea: Microcotylidae) from the gills of the abu mullet Liza abu (Heckel) in Atatürk Reservoir in southern Turkey is described. Among other features, the new species is easily distinguished from its three congeners, Solostamenides mugilis (Vogt, 1879), Solostamenides pseudomugilis (Hargis, 1956) and Solostamenides polyorchis Zhang & Yang, 2001, by having fewer hooks on the male copulatory organ (11 to 14), testes (5 to 9), and haptoral clamps (31 to 47).

  14. On thinking and not being able to think: reflections on viewing the Abu Ghraib photos.

    Science.gov (United States)

    Moss, Donald B

    2007-04-01

    Using experiences from childhood, from encounters with contemporary art, from clinical experience, and, most elaborately, from an initial viewing of the Abu Ghraib photos, the author argues that the interpretability of experience depends upon its being legible. This legibility, in turn, depends upon the interpreter maintaining contact with his/her own capacities for thought, and, more fundamentally, with the vitally necessary community of others with whom he/she shares those capacities.

  15. Comunicación y territorialización. Extraños en Abu Ghraib

    OpenAIRE

    Peñamarín, Cristina

    2009-01-01

    El trabajo estudia los medios en los procesos de territorialización y de formación de “causas colectivas”, que mueven la acción política, en los discursos públicos durante la guerra de Irak y en las fotografías de Abu Ghraib. Para ello, analiza la transmisión de emociones colectivizadoras de acuerdo con las diferentes categorizaciones de los otros. The paper studies media in territory processes and the formation of "collective causes", that can move political action, in public discourses d...

  16. State secret privilege versus human rights: lessons from the European Court of Human Rights ruling on the Abu Omar case / Arianna Vedaschi

    Index Scriptorium Estoniae

    Vedaschi, Arianna

    2017-01-01

    Riigisaladuse ülimuslikkusest julgeoleku eesmärgil ning inimõiguste ja põhivabaduste kaitse konventsiooni artikli 3 tõlgendamisest Euroopa Inimõiguste Kohtu Abu Omar lahendi (23.veebr 2016) põhjal

  17. Shear Elasticity and Shear Viscosity Imaging in Soft Tissue

    Science.gov (United States)

    Yang, Yiqun

    In this thesis, a new approach is introduced that provides estimates of shear elasticity and shear viscosity using time-domain measurements of shear waves in viscoelastic media. Simulations of shear wave particle displacements induced by an acoustic radiation force are accelerated significantly by a GPU. The acoustic radiation force is first calculated using the fast near field method (FNM) and the angular spectrum approach (ASA). The shear waves induced by the acoustic radiation force are then simulated in elastic and viscoelastic media using Green's functions. A parallel algorithm is developed to perform these calculations on a GPU, where the shear wave particle displacements at different observation points are calculated in parallel. The resulting speed increase enables rapid evaluation of shear waves at discrete points, in 2D planes, and for push beams with different spatial samplings and for different values of the f-number (f/#). The results of these simulations show that push beams with smaller f/# require a higher spatial sampling rate. The significant amount of acceleration achieved by this approach suggests that shear wave simulations with the Green's function approach are ideally suited for high-performance GPUs. Shear wave elasticity imaging determines the mechanical parameters of soft tissue by analyzing measured shear waves induced by an acoustic radiation force. To estimate the shear elasticity value, the widely used time-of-flight method calculates the correlation between shear wave particle velocities at adjacent lateral observation points. Although this method provides accurate estimates of the shear elasticity in purely elastic media, our experience suggests that the time-of-flight (TOF) method consistently overestimates the shear elasticity values in viscoelastic media because the combined effects of diffraction, attenuation, and dispersion are not considered. To address this problem, we have developed an approach that directly accounts for all

  18. Shear machines

    International Nuclear Information System (INIS)

    Astill, M.; Sunderland, A.; Waine, M.G.

    1980-01-01

    A shear machine for irradiated nuclear fuel elements has a replaceable shear assembly comprising a fuel element support block, a shear blade support and a clamp assembly which hold the fuel element to be sheared in contact with the support block. A first clamp member contacts the fuel element remote from the shear blade and a second clamp member contacts the fuel element adjacent the shear blade and is advanced towards the support block during shearing to compensate for any compression of the fuel element caused by the shear blade (U.K.)

  19. Renewable energy policies in the Gulf countries. A case study of the carbon-neutral 'Masdar City' in Abu Dhabi

    International Nuclear Information System (INIS)

    Reiche, Danyel

    2010-01-01

    The Gulf countries are largely dependent on exporting oil and natural gas for their national budgets. They mainly use domestic fossil fuels for their domestic energy supply. In spite of favorable geographic conditions, especially for solar energy, renewable energies are still a niche application. Abu Dhabi, besides Dubai, the most important emirate in the United Arab Emirates (UAE), has now started a process of 'transforming oil wealth into renewable energy leadership', and has set the long-term goal of a 'transition from a 20th Century, carbon-based economy into a 21st Century sustainable economy'. This article is a case study about 'Masdar City', a planned carbon-neutral town in Abu Dhabi. The article describes the key characteristics of Masdar City, analyses the drivers behind the project, identifies the main actors for its implementation, and seeks obstacles to creation and development as well as the policy behind Masdar City. Finally, a first judgment of possible diffusion effects of the project is done. (author)

  20. Occurrence and origin of mono-, di- and trimethylalkanes in modern and Holocene cyanobacterial mats from Abu Dhabi, United Arab Emirates

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Kenig, F.; Kock-van Dalen, A.C.; Rijpstra, W.I.C.; Huc, A.Y.; Leeuw, J.W. de

    1995-01-01

    n-Alkanes, highly branched isoprenoids, monomethylalkanes (MMAs), dimethylalkanes (DMAs), and trimethylalkanes (TMAs) are the most abundant components in the hydrocarbon fractions of extracts of four modern and two Holocene cyanobacterial mats (1500 and 5110 ± 170 y ) collected in Abu Dhabi (United

  1. PREPARASI KATALIS ABU KULIT KERANG UNTUK TRANSESTERIFIKASI MINYAK NYAMPLUNG MENJADI BIODIESEL (Preparation of Cockle Shell Powder Catalyst for Transesterificationof Calophyllumi inophyllum L. Oil to Biodiesel

    Directory of Open Access Journals (Sweden)

    Zuhra Zuhra

    2015-05-01

    menggunakan katalis padat dari kulit kerang. Dari pola XRD mengindikasikan bahwa CaCO3 terkonversi dari kulit kerang sempurna menjadi CaO ketika kulit kerang dikalsinasi pada suhu 900 oC. Hasil rekaman SEM diperoleh ukuran partikel katalis setelah dipijar menjadi kecil. Aktivitas katalis tertinggi diperoleh pada penggunaan abu kulit kerang yang dikalsinasi pada suhu 900 oC. Rendemenmetil ester tertinggi mencapai 87,4% setelah 3 jam reaksi. Katalis abu kulit kerang telah terbukti dapat digunakan untuk reaksi transesterifikasi minyak nabati menjadi biodiesel. Kata kunci: Kulit kerang, biodiesel, katalis heterogen, kalsium oksida, minyak nyamplung, transesterikasi

  2. Electromagnetic mapping of buried paleochannels in eastern Abu Dhabi Emirate, U.A.E.

    Science.gov (United States)

    Fitterman, D.V.; Menges, C.M.; Al Kamali, A.M.; Essa, Jama F.

    1991-01-01

    Transient electromagnetic soundings and terrain conductivity meter measurements were used to map paleochannel geometry in the Al Jaww Plain of eastern Abu Dhabi Emirate, U.A.E. as part of an integrated hydrogeologic study of the Quaternary alluvial aquifer system. Initial interpretation of the data without benefit of well log information was able to map the depth to a conductive clay layer of Tertiary age that forms the base of the aquifer. Comparison of the results with induction logs reveals that a resistive zone exists that was incorporated into the interpretation and its lateral extent mapped with the transient electromagnetic sounding data. ?? 1991.

  3. An ethnozoological study in the adjoining areas of Mount Abu wildlife sanctuary, India

    Directory of Open Access Journals (Sweden)

    Mahawar Madan

    2010-02-01

    Full Text Available Abstract Background There is evidence that human beings are familiar with use of animals for food, cloth, medicine, etc. since ancient times. Enormous work has been done on ethnobotany and traditional medicine. Like plants, animal and their products are also possessing medicinal properties that can be exploited for the benefit of human beings. In India, many ethnic communities are dispersed all over the country and these people are still totally depended on local traditional medicinal system for their health care. India is gifted with faunal and floral biodiversity, Mount Abu wildlife sanctuary is also one of them, and thus the aim of this work was to take an ethnozoological field survey among Garasiya people (main tribal group of this area in the adjoining areas of this sanctuary. Method In order to document the ethnozoological information about animal and their products prevalent among these people in the adjoining area of Mount Abu wildlife sanctuary, a study was carried out from January, 2008 to April, 2008. Data were collected through semi-structured questionnaire and open interview with 25 (16 male and 9 female selected Garasiya people. The name of animal and other ethnozoological information were documented. Photographs and discussion were also recorded with the help of camera and voice recorder. Result A total of 24 animal species were used in 35 different medicinal purposes including asthma, weakness, tuberculosis, cough, paralysis and blister and for other religious purposes. It has been find out that animal used by Garasiya, consist of fourteen mammals, five birds, three reptiles, one arthropods and one amphibian. The meat of Cynopterus sphinx used to relieved fever and cough has the highest FL (96% although flesh of Sus scrofa and tooth of Elephas maximus have the lowest FL (12%. Some protected species such as Elephas maximus (elephant, Semnopithecus priam (monkey, Cervus unicolor (sambhar were also mentioned as important medicinal

  4. An ethnozoological study in the adjoining areas of Mount Abu wildlife sanctuary, India.

    Science.gov (United States)

    Jaroli, D P; Mahawar, Madan Mohan; Vyas, Nitin

    2010-02-10

    There is evidence that human beings are familiar with use of animals for food, cloth, medicine, etc. since ancient times. Enormous work has been done on ethnobotany and traditional medicine. Like plants, animal and their products are also possessing medicinal properties that can be exploited for the benefit of human beings. In India, many ethnic communities are dispersed all over the country and these people are still totally depended on local traditional medicinal system for their health care. India is gifted with faunal and floral biodiversity, Mount Abu wildlife sanctuary is also one of them, and thus the aim of this work was to take an ethnozoological field survey among Garasiya people (main tribal group of this area) in the adjoining areas of this sanctuary. In order to document the ethnozoological information about animal and their products prevalent among these people in the adjoining area of Mount Abu wildlife sanctuary, a study was carried out from January, 2008 to April, 2008. Data were collected through semi-structured questionnaire and open interview with 25 (16 male and 9 female) selected Garasiya people. The name of animal and other ethnozoological information were documented. Photographs and discussion were also recorded with the help of camera and voice recorder. A total of 24 animal species were used in 35 different medicinal purposes including asthma, weakness, tuberculosis, cough, paralysis and blister and for other religious purposes. It has been find out that animal used by Garasiya, consist of fourteen mammals, five birds, three reptiles, one arthropods and one amphibian. The meat of Cynopterus sphinx used to relieved fever and cough has the highest FL (96%) although flesh of Sus scrofa and tooth of Elephas maximus have the lowest FL (12%). Some protected species such as Elephas maximus (elephant), Semnopithecus priam (monkey), Cervus unicolor (sambhar) were also mentioned as important medicinal resources. We also found that cough, asthma and

  5. Critical Success Factors in the Curriculum Alignment Process: The Case of the College of Business at Abu Dhabi University

    Science.gov (United States)

    Camba, Pitzel; Krotov, Vlad

    2015-01-01

    The main goals of this article are to (a) assist business schools in understanding the curriculum alignment process, and (b) uncover critical success factors in curriculum alignment. Based on a case study conducted at the College of Business at Abu Dhabi University, a detailed curriculum alignment process description is provided. The process…

  6. Uranium distributions in the mineral constituents of granitoid rocks and the associated pegmatites at Wadi Abu Had, north eastern desert, Egypt

    International Nuclear Information System (INIS)

    Nossair, L.M.; Moharem, A.F.; Abdel Warith, A.

    2007-01-01

    Wadi Abu Had area is located at the northern part of the Eastern Desert of Egypt. It covers about 55 km2 of the crystalline basement rocks stretching between latitudes 28o 15'- 28o 25' N and longitudes 32o 25' - 32o 35' E. Abu Had younger granites are fertile (uraniferous) granites as they possess U-contents greater than 11 ppm. Their associated pegmatites show higher U-contents than those of granitoid rocks and hosting secondary uranium minerals. Numerous unzoned and zoned pegmatite pockets are associated with the marginal parts of granodiorite and within younger granites. Zoned pegmatites are the most radioactive ones. They are composed of extremely coarse-grained milky quartz core, intermediate zone of mica and wall zone of feldspars. An alteration zone with secondary uranium minerals (uranophane and beta-uranophane) is found at the contact between quartz core and the intermediate zone.

  7. A GIS-BASED MULTI-CRITERIA EVALUATION SYSTEM FOR SELECTION OF LANDFILL SITES: a case study from Abu Dhabi, United Arab Emirates

    Directory of Open Access Journals (Sweden)

    S. M. Issa

    2012-07-01

    Full Text Available Landfill sites receive 92% of total annual solid waste produced by municipalities in the emirate of Abu Dhabi. In this study, candidate sites for an appropriate landfill location for the Abu Dhabi municipal area are determined by integrating geographic information systems (GIS and multi-criteria evaluation (MCE analysis. To identify appropriate landfill sites, eight input map layers including proximity to urban areas, proximity to wells and water table depth, geology and topography, proximity to touristic and archeological sites, distance from roads network, distance from drainage networks, and land slope are used in constraint mapping. A final map was generated which identified potential areas showing suitability for the location of the landfill site. Results revealed that 30% of the study area was identified as highly suitable, 25% as suitable, and 45% as unsuitable. The selection of the final landfill site, however, requires further field research.

  8. Utilizations and Perceptions of Emergency Medical Services by Patients with ST-Segments Elevation Acute Myocardial Infarction in Abu Dhabi: A Multicenter Study.

    Science.gov (United States)

    Callachan, Edward Lance; Alsheikh-Ali, Alawi A; Nair, Satish Chandrasekhar; Bruijns, Stevan; Wallis, Lee A

    2016-01-01

    Data on the use of emergency medical services (EMS) by patients with cardiac conditions in the Gulf region are scarce, and prior studies have suggested underutilization. Patient perception and knowledge of EMS care is critical to proper utilization of such services. To estimate utilization, knowledge, and perceptions of EMS among patients with ST-elevation myocardial infarction (STEMI) in the Emirate of Abu Dhabi. We conducted a multicenter prospective study of consecutive patients admitted with STEMI in four government-operated hospitals in Abu Dhabi. Semi-structured interviews were conducted with patients to assess the rationale for choosing their prehospital mode of transport and their knowledge of EMS services. Of 587 patients with STEMI (age 51 ± 11 years, male 95%), only 15% presented through EMS, and the remainder came via private transport. Over half of the participants (55%) stated that they did not know the telephone number for EMS. The most common reasons stated for not using EMS were that private transport was quicker (40%) or easier (11%). A small percentage of participants (7%) did not use EMS because they did not think their symptoms were cardiac-related or warranted an EMS call. Stated reasons for not using EMS did not significantly differ by age, gender, or primary language of the patients. EMS care for STEMI is grossly underutilized in Abu Dhabi. Patient knowledge and perceptions may contribute to underutilization, and public education efforts are needed to raise their perception and knowledge of EMS.

  9. Preliminary crustal deformation model deduced from GPS and earthquakes’ data at Abu-Dabbab area, Eastern Desert, Egypt

    Science.gov (United States)

    Mohamed, Abdel-Monem S.; Hosny, A.; Abou-Aly, N.; Saleh, M.; Rayan, A.

    2013-06-01

    A local geodetic network consisting of eleven benchmarks has been established to study the recent crustal deformation in the Abu-Dabbab area. Seven campaigns of GPS measurements have been collected started from October 2008 and ended in March 2012. The collected data were processed using Bernese version 5.0, and the result values were adjusted to get the more accurate positions of the GPS stations. The magnitudes of horizontal displacements are variable from one epoch to another and in the range of 1-3 (±0.2) mm/yr. Due to the differences in rates of the horizontal displacement; the area is divided into two main blocks. The first one, moves to the east direction of about 3 mm/yr, while the second block, moves to the SW direction of about 6 mm/yr. According to the strain fields that were calculated for the different epochs of measurement, the main force is compression force and is taken the NW-SE to NWW-SEE direction. This force could be because of local and regional tectonic processes affecting on the study area. The maximum values of compression stress are found in the southern central and western part of study area. Estimated accumulation of this strain energy may be considered as an indicator of the possibility of earthquake occurrence. From the seismic tomography study, the 3D Vp and Vp/Vs crustal models indicate high Vp/Vs values forms an elongated anomaly, in the central part of the study area, that extends from a depth of 12 km to about 1-2 km of depth is obtained. By using this crustal model in relocations all seismicity informed that most of the seismicity strongly tend to occur in a cluster manner exactly above the southern part of the study area. Based on the conducted source mechanism study, it is noticed that shallow earthquakes are associated by a high CLVD ratio (up to 40%). Furthermore, initiation of a high level seismic activity, without a large seismic main shock is observed in the Abu-Dabbab area. The distribution of micro-earthquakes tends to

  10. SINTESIS SILIKA AEROGEL DENGAN BAHAN DASAR ABU BAGASSE

    Directory of Open Access Journals (Sweden)

    Nazriati Nazriati

    2012-05-01

    Full Text Available SYNTHESIS OF SILICA AEROGEL FROM BAGASSE ASH. Synthesis of silica aerogel from bagasse ash was done by alkaline extraction followed by sol-gel. Bagasse ash was extracted with NaOH at its boiling temperature for one hour with continue stirring, to produce sodium silicate. Subsequently, sodium silicate was pass through ionic exchanger resin, to produces silicic acid (SA. Silicic acid solution was then added with TMCS and HMDS as surface modifier agent. In order to form gel pH must be adjusted to final pH of 8-9 by addition of NH4OH solution. The resulting gel then was aged and dried at ambient pressure and at a certain time and temperature. Characterization of products was done by measuring its pore volume, surface area, and hydrophobisity (contact angle. TMCS serves as water expeller from the pores and subsequently surface was modified by HMDS and TMCS. HMDS content will linearly increase surface area, pore volume, and the contact angle of the resulting silica aerogel. Characteristics of silica aerogel was generated by varying the composition of the SA:TMCS:HMDS resulting has a surface area of 50-488 m2/g, pore volume from 0.2 to 0.9 m3 /g, the contact angle of 48-119 and pore diameter ranging from 5.7-22.56 nm. Based on the resulting pore diameter, the synthesized of silica aerogel categorized as mesoporous.      Abstrak   Sintesis silika aerogel dari bahan dasar abu bagasse dilakukan dengan ekstraksi basa dan diikuti dengan sol-gel. Abu bagasse diekstrak dengan NaOH pada suhu didihnya sambil diaduk selama satu jam, menghasilkan sodium silikat. Selanjutnya, sodium silikat dilewatkan resin penukar ion, menghasilkan asam silicic (SA. Larutan asam silicic kemudian ditambahkan trimethy­l­chlorosilane (TMCS dan hexamethyldisilazane (HMDS sebagai agen pemodifikasi permukaan. Untuk terjadinya gel pH diatur hingga mencapai 8-9 dengan penambahan larutan NH4OH. Gel yang dihasilkan kemudian di-aging dan dikeringkan pada tekanan ambien pada suhu dan

  11. Shear Resistance Variations in Experimentally Sheared Mudstone Granules: A Possible Shear-Thinning and Thixotropic Mechanism

    Science.gov (United States)

    Hu, Wei; Xu, Qiang; Wang, Gonghui; Scaringi, Gianvito; Mcsaveney, Mauri; Hicher, Pierre-Yves

    2017-11-01

    We present results of ring shear frictional resistance for mudstone granules of different size obtained from a landslide shear zone. Little rate dependency of shear resistance was observed in sand-sized granules in any wet or dry test, while saturated gravel-sized granules exhibited significant and abrupt reversible rate-weakening (from μ = 0.6 to 0.05) at about 2 mm/s. Repeating resistance variations occurred also under constant shear displacement rate. Mudstone granules generate mud as they are crushed and softened. Shear-thinning and thixotropic behavior of the mud can explain the observed behavior: with the viscosity decreasing, the mud can flow through the coarser soil pores and migrate out from the shear zone. This brings new granules into contact which produces new mud. Thus, the process can start over. Similarities between experimental shear zones and those of some landslides in mudstone suggest that the observed behavior may play a role in some landslide kinematics.

  12. Utilizations and Perceptions of Emergency Medical Services by Patients with ST-Segments Elevation Acute Myocardial Infarction in Abu Dhabi: A Multicenter Study

    Science.gov (United States)

    Callachan, Edward Lance; Alsheikh-Ali, Alawi A.; Nair, Satish Chandrasekhar; Bruijns, Stevan; Wallis, Lee A.

    2016-01-01

    Background: Data on the use of emergency medical services (EMS) by patients with cardiac conditions in the Gulf region are scarce, and prior studies have suggested underutilization. Patient perception and knowledge of EMS care is critical to proper utilization of such services. Objectives: To estimate utilization, knowledge, and perceptions of EMS among patients with ST-elevation myocardial infarction (STEMI) in the Emirate of Abu Dhabi. Methods: We conducted a multicenter prospective study of consecutive patients admitted with STEMI in four government-operated hospitals in Abu Dhabi. Semi-structured interviews were conducted with patients to assess the rationale for choosing their prehospital mode of transport and their knowledge of EMS services. Results: Of 587 patients with STEMI (age 51 ± 11 years, male 95%), only 15% presented through EMS, and the remainder came via private transport. Over half of the participants (55%) stated that they did not know the telephone number for EMS. The most common reasons stated for not using EMS were that private transport was quicker (40%) or easier (11%). A small percentage of participants (7%) did not use EMS because they did not think their symptoms were cardiac-related or warranted an EMS call. Stated reasons for not using EMS did not significantly differ by age, gender, or primary language of the patients. Conclusions: EMS care for STEMI is grossly underutilized in Abu Dhabi. Patient knowledge and perceptions may contribute to underutilization, and public education efforts are needed to raise their perception and knowledge of EMS. PMID:27512532

  13. Cornici di tortura Lo scandalo di Abu Ghraib come rituale mediatizzato tra fotogiornalismo e arte contemporanea

    Directory of Open Access Journals (Sweden)

    Marco Solaroli

    2010-11-01

    Full Text Available This paper deals with the scandal of Abu Ghraib. The diffusion of the torture photographs is analyzed as a peculiar form of mediatized ritual, which has cristallized them in the public memory and performatively activated a number of practices of creative re-contextualization and symbolic re-articulation. In particular, the paper problematizes a wide range of forms of artistic representations of the torture photographs, according to three main analytical dimensions: inter-iconic translation, authorial intentions, degree of institutionalization.

  14. Study on shear properties of coral sand under cyclic simple shear condition

    Science.gov (United States)

    Ji, Wendong; Zhang, Yuting; Jin, Yafei

    2018-05-01

    In recent years, the ocean development in our country urgently needs to be accelerated. The construction of artificial coral reefs has become an important development direction. In this paper, experimental studies of simple shear and cyclic simple shear of coral sand are carried out, and the shear properties and particle breakage of coral sand are analyzed. The results show that the coral sand samples show an overall shear failure in the simple shear test, which is more accurate and effective for studying the particle breakage. The shear displacement corresponding to the peak shear stress of the simple shear test is significantly larger than that corresponding to the peak shear stress of the direct shear test. The degree of particle breakage caused by the simple shear test is significantly related to the normal stress level. The particle breakage of coral sand after the cyclic simple shear test obviously increases compared with that of the simple shear test, and universal particle breakage occurs within the whole particle size range. The increasing of the cycle-index under cyclic simple shear test results in continuous compacting of the sample, so that the envelope curve of peak shearing force increases with the accumulated shear displacement.

  15. Shear strength of non-shear reinforced concrete elements

    DEFF Research Database (Denmark)

    Hoang, Cao linh

    1997-01-01

    The paper deals with the plastic shear strength of non shear reinforced T-beams.The influence of an un-reinforced flange on the shear capacity is investigated by considering a failure mechanism involving crack sliding in the web and a kind of membrane action over an effective width of the flange...

  16. School Children's Use of Digital Devices, Social Media and Parental Knowledge and Involvement--The Case of Abu Dhabi

    Science.gov (United States)

    Badri, Masood; Alnuaimi, Ali; Al Rashedi, Asma; Yang, Guang; Temsah, Khaled

    2017-01-01

    This paper looks at the usage of social media devices and applications, and parental knowledge and involvement among Abu Dhabi children in Grade 6 or higher. It examines the young children's usage of personal computers, mobile phones and tablet PCs, and social media related apps. The paper tries to understand the reasons for joining or not joining…

  17. Recent benthic foraminifera and sedimentary facies from mangrove swamps and channels of Abu Dhabi (United Arab Emirates)

    Science.gov (United States)

    Fiorini, Flavia; Odeh, Weaam A. S. Al; Lokier, Stephen W.; Paul, Andreas

    2016-04-01

    Zonation of Recent mangrove environments can be defined using benthic foraminifera, however, little is known about foraminifera from mangrove environments of the Arabian Gulf. The objective of this study is to produce a detailed micropaleontological and sedimentological analysis to identify foraminiferal associations in several coastline environments (mangrove swamps and channels) located on the eastern side of Abu Dhabi Island (UAE). Detailed sediment sampling collection in mangal environments of Eastern Abu Dhabi was carried out to assess the distribution of living and dead benthic foraminifera in different sedimentary facies in the mangal and in the surrounding area comprising natural environments of the upper and lower intertidal area (mud flats and channels) and areas modified by anthropogenic activities (dredged channels). The fine-grain sediments collected near mangrove (Avicenna marina) roots presented a high abundance of living and dead foraminifera tests. The assemblages in these samples show very low diversity and are almost entirely constituted of small-sized opportunistic species belonging to the genera Ammonia and Elphidium. In particular: • Samples collected on the mud flat and in ponds at the margin of the channel show a foraminiferal assemblage characterised by abundant foraminifera belonging to the genera Ammonia, Elphidium, Triloculina, Quinqueloculina, Peneroplis and Spirolina. • Samples collected in the lower (wet) intertidal area close to Avicenna marina roots, presented a low-diversity assemblage mostly comprising opportunistic foraminifera of the genera Ammonia and Elphidium along with rare miliolidae. • Samples from the upper intertidal area (dry) close to Avicenna marina roots, produced an assemblage exclusively composed of small-sized opportunistic Ammonia and Elphidium, together with abundant specimens belonging to the genera Trochammina. Throchammina specimens have not been previously recorded from Recent sedimentary samples of

  18. Medical ethics at Guantanamo Bay and Abu Ghraib: the problem of dual loyalty.

    Science.gov (United States)

    Clark, Peter A

    2006-01-01

    Although knowledge of torture and physical and psychological abuse was widespread at both the Guantanamo Bay detention facility and Abu Ghraib prison in Iraq, and known to medical personnel, there was no official report before the January 2004 Army investigation of military health personnel reporting abuse, degradation or signs of torture. Military medical personnel are placed in a position of a "dual loyalty" conflict. They have to balance the medical needs of their patients, who happen to be detainees, with their military duty to their employer. The United States military medical system failed to protect detainee's human rights, violated the basic principles of medical ethics and ignored the basic tenets of medical professionalism.

  19. Hydrogeochemical analysis and evaluation of groundwater in the reclaimed small basin of Abu Mina, Egypt

    Science.gov (United States)

    Salem, Zenhom E.; Atwia, Mohamed G.; El-Horiny, Mohamed M.

    2015-12-01

    Agricultural reclamation activities during the last few decades in the Western Nile Delta have led to great changes in the groundwater levels and quality. In Egypt, changing the desert land into agricultural land has been done using transferred Nile water (through irrigation canal systems) or/and groundwater. This research investigates the hydrogeochemical changes accompanying the reclamation processes in the small basin of Abu Mina, which is part of the Western Nile Delta region. In summer 2008, 23 groundwater samples were collected and groundwater levels were measured in 40 observation wells. Comparing the groundwater data of the pre-reclamation (1974) and the post-reclamation (2008) periods, groundwater seems to have been subjected to many changes: rise in water level, modification of the flow system, improvement of water quality, and addition of new salts through dissolution processes. Generally, Abu Mina basin is subdivided into two areas, recharge and discharge. The dissolution and mixing were recognized in the recharge areas, while the groundwater of the discharge region carries the signature of the diluted pre-reclamation groundwater. The salts of soil and aquifer deposits play an important role in the salt content of the post and pre-reclamation groundwater. NaCl was the predominant water type in the pre-reclamation groundwater, while CaSO4, NaCl and MgSO4 are the common chemical facies in the post-reclamation groundwater. The post-reclamation groundwater mostly indicates mixing between the pre-reclamation groundwater and the infiltrated freshwater with addition of some ions due to interaction with soil and sediments.

  20. Renewable energy policies in the Gulf countries. A case study of the carbon-neutral 'Masdar City' in Abu Dhabi

    Energy Technology Data Exchange (ETDEWEB)

    Reiche, Danyel [Department of Political Studies and Public Administration (PSPA), American University of Beirut, Jesup Hall, Room 205, P.O. Box 11-0236, Riad El Solh, Beirut 1107 2020 (Lebanon); Wuppertal Institute (Germany)

    2010-01-15

    The Gulf countries are largely dependent on exporting oil and natural gas for their national budgets. They mainly use domestic fossil fuels for their domestic energy supply. In spite of favorable geographic conditions, especially for solar energy, renewable energies are still a niche application. Abu Dhabi, besides Dubai, the most important emirate in the United Arab Emirates (UAE), has now started a process of 'transforming oil wealth into renewable energy leadership', and has set the long-term goal of a 'transition from a 20th Century, carbon-based economy into a 21st Century sustainable economy'. This article is a case study about 'Masdar City', a planned carbon-neutral town in Abu Dhabi. The article describes the key characteristics of Masdar City, analyses the drivers behind the project, identifies the main actors for its implementation, and seeks obstacles to creation and development as well as the policy behind Masdar City. Finally, a first judgment of possible diffusion effects of the project is done. (author)

  1. Renewable Energy Policies in the Gulf countries: A case study of the carbon-neutral 'Masdar City' in Abu Dhabi

    Energy Technology Data Exchange (ETDEWEB)

    Reiche, Danyel, E-mail: dr09@aub.edu.l [Department of Political Studies and Public Administration (PSPA), American University of Beirut, Jesup Hall, Room 205, P.O. Box 11-0236, Riad El Solh, Beirut 1107 2020 (Lebanon); Wuppertal Institute (Germany)

    2010-01-15

    The Gulf countries are largely dependent on exporting oil and natural gas for their national budgets. They mainly use domestic fossil fuels for their domestic energy supply. In spite of favorable geographic conditions, especially for solar energy, renewable energies are still a niche application. Abu Dhabi, besides Dubai, the most important emirate in the United Arab Emirates (UAE), has now started a process of 'transforming oil wealth into renewable energy leadership,' and has set the long-term goal of a 'transition from a 20th Century, carbon-based economy into a 21st Century sustainable economy.' This article is a case study about 'Masdar City,' a planned carbon-neutral town in Abu Dhabi. The article describes the key characteristics of Masdar City, analyses the drivers behind the project, identifies the main actors for its implementation, and seeks obstacles to creation and development as well as the policy behind Masdar City. Finally, a first judgment of possible diffusion effects of the project is done.

  2. Makam Sayyid Husein Bin Abu Bakar Al-Aydarus: Jaringan Spiritual Usmani Di Indonesia Akhir Abad Ke-19

    OpenAIRE

    SUPRATMAN, FRIAL RAMADHAN

    2016-01-01

    This article investigates Indonesian history with transnational approach espe- cially in tracing social community of Indonesia in the context of globalization during nineteenth century. In this article, author focuses on holy tomb of ulama or saint (wali), Sayyid Husein bin Abu Bakar al-Aydarus, who died in the late eighteenth century and buried in Batavia. Although he died more than a century a go, his influence through tomb still can be sensed until now. In the nineteenth century, the tomb ...

  3. OIL SPILL DETECTION AND MONITORING OF ABU DHABI COASTAL ZONE USING KOMPSAT-5 SAR IMAGERY

    Directory of Open Access Journals (Sweden)

    H. A. Harahsheh

    2016-06-01

    Full Text Available Abu Dhabi Government endorsed vision for its Maritime Strategy ‘A safe, secure and sustainable maritime domain for Abu Dhabi'. This research study share this vision using the concept of monitoring as tool for marine protection against any possible oil pollution. The best technology to detect and monitor oil pollution and in particularly oil spill is SAR imagery In this case study we chose KOMPSAT-5 SAR. KOMPSAT-5 carries X-band SAR for earth observation, and is capable of day-and-night imaging under all weather condition. It provides three operation modes: High Resolution Mode to provide 1 m resolution, Standard Mode to provide 3 m resolution and Wide Swath Mode to provide 20 m resolution with 100 km swath at 550 km altitude, with four modes of polarization. KOMPSAT-5 provides products for various applications; security and defense, mapping, and natural resource management, environmental monitoring, disaster monitoring and more. For our case study we chose to work with Wide Swath mode (WS with Vertical polarization (VV to cover a wide area of interest located to the north west of Abu Dhabi including some important islands like ”Zirku Island”, and areas with oil production activities. The results of data acquired on 4th May 2015 show some spot of oil spill with length estimated about 3 KM, and the daily satellite data acquisition over the period July 24 through July 31 shows serious and many oil spill events some are small, but many others are considered to be big with area size around 20 km2. In the context of oil spill pollution in the seas, we have to consider the development and increase of overseas transportation, which is an important factor for both social and economic sectors. The harmful effects of marine pollution are numerous, from the damage of marine life to the damage of the aquatic ecosystem as whole. As such, the need for oil slick detection is crucial, for the location of polluted areas and to evaluate slick drift to

  4. Oil Spill Detection and Monitoring of Abu Dhabi Coastal Zone Using KOMPSAT-5 SAR Imagery

    Science.gov (United States)

    Harahsheh, H. A.

    2016-06-01

    Abu Dhabi Government endorsed vision for its Maritime Strategy `A safe, secure and sustainable maritime domain for Abu Dhabi'. This research study share this vision using the concept of monitoring as tool for marine protection against any possible oil pollution. The best technology to detect and monitor oil pollution and in particularly oil spill is SAR imagery In this case study we chose KOMPSAT-5 SAR. KOMPSAT-5 carries X-band SAR for earth observation, and is capable of day-and-night imaging under all weather condition. It provides three operation modes: High Resolution Mode to provide 1 m resolution, Standard Mode to provide 3 m resolution and Wide Swath Mode to provide 20 m resolution with 100 km swath at 550 km altitude, with four modes of polarization. KOMPSAT-5 provides products for various applications; security and defense, mapping, and natural resource management, environmental monitoring, disaster monitoring and more. For our case study we chose to work with Wide Swath mode (WS) with Vertical polarization (VV) to cover a wide area of interest located to the north west of Abu Dhabi including some important islands like "Zirku Island", and areas with oil production activities. The results of data acquired on 4th May 2015 show some spot of oil spill with length estimated about 3 KM, and the daily satellite data acquisition over the period July 24 through July 31 shows serious and many oil spill events some are small, but many others are considered to be big with area size around 20 km2. In the context of oil spill pollution in the seas, we have to consider the development and increase of overseas transportation, which is an important factor for both social and economic sectors. The harmful effects of marine pollution are numerous, from the damage of marine life to the damage of the aquatic ecosystem as whole. As such, the need for oil slick detection is crucial, for the location of polluted areas and to evaluate slick drift to protect the coastline

  5. Out-of-School Experience Categories Influencing Interest in Biology of Secondary School Students by Gender: Exploration on an Abu Dhabi Sample

    Science.gov (United States)

    Badri, Masood; Yang, Guang; Al Mazroui, Karima; Mohaidat, Jihad; Al Rashedi, Asma; Al Housani, Najwa

    2017-01-01

    This study employed the international Relevance of Science Education questionnaire to survey the interest in biology and the out-of-school experiences of Abu Dhabi secondary school students (median age 17, mean age 17.53 and mode age of 16) in the third semester of 2014. It included 3100 participants. An exploratory factor analysis was used to…

  6. Influence of Chemical Parameters on Artemia sp. (Crustacea: Anostraca Population in Al Wathba Lake in the Abu Dhabi Emirate, UAE

    Directory of Open Access Journals (Sweden)

    Anitha Saji

    2016-04-01

    Full Text Available Long term monitoring programme on Brine shrimp (Artemia sp. is being carried out by the Environment Agency, Abu Dhabi, United Arab Emirates (EAD with the prime purpose of understanding the population dynamics, ecology and habitat requirements of Artemia at Al Wathba Lake, situated within Al Wathba Wetland Reserve, which is an artificial wetland near Abu Dhabi City. The present study, being a component of this programme, intends to understand the influence of chemical parameters such as dissolved oxygen, nitrate, nitrite, phosphate, ammonia and total organic carbon on Artemia biomass and cyst production at different sites of the Al Wathba Lake. The study was carried out by sampling lake water quarterly for a period of 5 years from 2010 to 2014. The Artemia population was found to have direct impact of the above mentioned parameters on its abundance. The abundance was highest during the year 2010. Further, temperature, dissolved oxygen, nitrate and cadmium were found to be the most crucial parameters for production of Artemia. The study further aimed to determine the significant relationship between physico-chemical parameters and Artemia sp. population dynamics and cyst production.

  7. Maslyuzhenko D.N. Turko-Mongol Traditions in the “State of Nomadic Uzbeks” of Abu al-Khair Khan

    Directory of Open Access Journals (Sweden)

    D.N. Maslyuzhenko

    2014-09-01

    Full Text Available The author of this article identifies the daily and political traditions in the Khanate of Abu al-Khair, which researchers traditionally call the “State of nomadic Uzbeks”. This State was created in the south of Western Siberia in the 1430’s and annexed by military means to the land of Shiban’s (the younger brother of Batu descendants. The overwhelming majority of researchers consider it as a Muslim State since its very foundation, substantiating their allegations by indication both on the reading of khutba in honor of Khan after he took the “throne of Sain Khan” and on the presence of the sheikhs and Sufis in his entourage. At the same time, the authority of Abu al-Khair had the strong support of nomadic elite of more than twenty tribes. Precisely this elite, its inquiries and interests, which were advocated on the nobility councils, formed the existing political and daily traditions. These traditions reflect the preservation of Turko-Mongol customs among nomadic populations. We can find analogies of these practices in the earlier customs among the precursors of post-Golden Horde State, i.e., in the Mongol Empire and the ulus of Jochi. Traditions of the Abu al-Khair’s Khanate represented a phenomenon of cultural inertia, which were restored in the conditions of Islamization and could become the adats. This effect is particularly significant in view of the specific attitude of Sufi tariqats to the phenomena of social life. In political terms, of particular importance among these was the restoration of the Toy and the related kurultay that could take place in accordance with the existing steppe (animals calendar. The khans restored the ritual of robes and belts’ distribution as the main mechanism for redeployment of posts and responsibilities among the steppe aristocracy. Military tradition was also focused on samples of the previous time, which was particularly manifested in the selection of wings and avant-garde. In the course

  8. Experimental study of shear rate dependence in perpetually sheared granular matter

    Science.gov (United States)

    Liu, Sophie Yang; Guillard, François; Marks, Benjy; Rognon, Pierre; Einav, Itai

    2017-06-01

    We study the shear behaviour of various granular materials by conducting novel perpetual simple shear experiments over four orders of magnitude of relatively low shear rates. The newly developed experimental apparatus employed is called "3D Stadium Shear Device" which is an extended version of the 2D Stadium Shear Device [1]. This device is able to provide a non-radial dependent perpetual shear flow and a nearly linear velocity profile between two oppositely moving shear walls. Using this device, we are able to test a large variety of granular materials. Here, we demonstrate the applicability of the device on glass beads (diameter 1 mm, 3 mm, and 14 mm) and rice. We particularly focus on studying these materials at very low inertial number I ranging from 10-6 to 10-2. We find that, within this range of I, the friction coefficient μ of glass beads has no shear rate dependence. A particularly appealing observation comes from testing rice, where the attainment of critical state develops under much longer duration than in other materials. Initially during shear we find a value of μ similar to that found for glass beads, but with time this value decreases gradually towards the asymptotic critical state value. The reason, we believe, lies in the fact that rice grains are strongly elongated; hence the time to achieve the stable μ is primarily controlled by the time for particles to align themselves with respect to the shear walls. Furthermore, the initial packing conditions of samples also plays a role in the evolution of μ when the shear strain is small, but that impact will eventually be erased after sufficient shear strain.

  9. Experimental study of shear rate dependence in perpetually sheared granular matter

    Directory of Open Access Journals (Sweden)

    Liu Sophie Yang

    2017-01-01

    Full Text Available We study the shear behaviour of various granular materials by conducting novel perpetual simple shear experiments over four orders of magnitude of relatively low shear rates. The newly developed experimental apparatus employed is called “3D Stadium Shear Device” which is an extended version of the 2D Stadium Shear Device [1]. This device is able to provide a non-radial dependent perpetual shear flow and a nearly linear velocity profile between two oppositely moving shear walls. Using this device, we are able to test a large variety of granular materials. Here, we demonstrate the applicability of the device on glass beads (diameter 1 mm, 3 mm, and 14 mm and rice. We particularly focus on studying these materials at very low inertial number I ranging from 10−6 to 10−2. We find that, within this range of I, the friction coefficient μ of glass beads has no shear rate dependence. A particularly appealing observation comes from testing rice, where the attainment of critical state develops under much longer duration than in other materials. Initially during shear we find a value of μ similar to that found for glass beads, but with time this value decreases gradually towards the asymptotic critical state value. The reason, we believe, lies in the fact that rice grains are strongly elongated; hence the time to achieve the stable μ is primarily controlled by the time for particles to align themselves with respect to the shear walls. Furthermore, the initial packing conditions of samples also plays a role in the evolution of μ when the shear strain is small, but that impact will eventually be erased after sufficient shear strain.

  10. Applying post classification change detection technique to monitor an Egyptian coastal zone (Abu Qir Bay

    Directory of Open Access Journals (Sweden)

    Mamdouh M. El-Hattab

    2016-06-01

    Full Text Available Land cover changes considered as one of the important global phenomena exerting perhaps one of the most significant effects on the environment than any other factor. It is, therefore, vital that accurate data on land cover changes are made available to facilitate the understanding of the link between land cover changes and environmental changes to allow planners to make effective decisions. In this paper, the post classification approach was used to detect and assess land cover changes of one of the important coastal zones in Egypt, Abu Qir Bay zone, based on the comparative analysis of independently produced classification images of the same area at different dates. In addition to satellite images, socioeconomic data were used with the aid of land use model EGSLR to indicate relation between land cover and land use changes. Results indicated that changes in different land covers reflected the changes in occupation status in specific zones. For example, in the south of Idku Lake zone, it was observed that the occupation of settlers changed from being unskilled workers to fishermen based on the expansion of the area of fish farms. Change rates increased dramatically in the period from 2004 to 2013 as remarkable negative changes were found especially in fruits and palm trees (i.e. loss of about 66 km2 of land having fruits and palm trees due to industrialization in the coastal area. Also, a rapid urbanization was monitored along the coastline of Abu Qir Bay zone due to the political conditions in Egypt (25th of January Revolution within this period and which resulted to the temporary absence of monitoring systems to regulate urbanization.

  11. The development of stromatolitic features from laminated microbial mats in the coastal sabkha of Abu Dhabi (UAE)

    Science.gov (United States)

    Paul, Andreas; Lessa Andrade, Luiza; Dutton, Kirsten E.; Sherry, Angela; Court, Wesley M.; Van der Land, Cees; Lokier, Stephen W.; Head, Ian M.

    2017-04-01

    Stromatolitic features are documented from both marine and terrestrial environments worldwide. These features form through a combination of trapping and binding of allochthonous grains, and through microbially mediated and/or controlled precipitation of carbonate minerals. The combined effects of these processes result in the continuous vertical and lateral growth of stromatolites. While the Abu Dhabi coastal sabkha is well known for a vast microbial mat belt that is dominated by continuous polygonal and internally-laminated microbial mats, no stromatolitic features have been reported from this area so far. In this study, we report evidence for stromatolitic features from the coastal sabkha of Abu Dhabi, based on observations in an intertidal but permanently submerged pool. This pool lies embedded within the laminated microbial mat zone, and is marked by the development of true laminated stromatolite at its margins and microbial build-ups at its centre. In order to characterise processes that lead to the formation of these stromatolitic features, and to develop a conceptual model that describes their development in the context of variations in sea level, tidal energy and other environmental factors, we employ a multitude of environmental, sedimentological, mineralogical and geochemical methods. These methods include the analysis of water data in terms of temporal variations in temperature, salinity, dissolved oxygen and water level, the analysis of petrographic thin sections of both lithified and unlithified features as well as an analysis of the stromatolites' mineralogical composition, and the amounts of incorporated organic carbon and calcium carbonate. Initial results suggest that the development of the observed stromatolitic features in the coastal sabkha of Abu Dhabi is the result of a complex interplay between simultaneous erosion of laminated microbial mat, and biotic/abiotic lithification processes. Initially, the location of this pool was characterised by

  12. Teks al-Qur’an dalam Pandangan Nashr Hamid Abu Zayd

    Directory of Open Access Journals (Sweden)

    Ahmad Fauzan

    2015-03-01

    Full Text Available A thought to have an important role to someone. If true thinking it will affect a good understanding leads to attitudes and behavior. However, if the faulty thinking that very result in the destruction of the attitudes and behavior and may even lead to the destruction of one’s Islamic faith. For a Muslim, thinking of concepts related to faith must rely on the descriptions that have been described by Allah SWT and His Messenger and do not necessary diligence in achieving it as the judge actions in fiqh. Because the truth related to faith is not what will go in or unreasonable, scientific or unscientific. But the truth of faith is related to what are established Allah SWT and His Messenger, although not satisfying logic and can not sensed. Related to the above, this paper tries to explain an example of a false thought linked to al-Qur’an faith brought by a prominent modernist Islamic thinker, Nasr Hamid Abu Zaid. Because, to know the truth can sometimes be achieved after knowing a falsehood.

  13. 75 FR 2921 - In the Matter of the Designation of Said Ali al-Shihri, Also Known as Abu-Sayyaf, Also Known as...

    Science.gov (United States)

    2010-01-19

    ... DEPARTMENT OF STATE [Public Notice 6872] In the Matter of the Designation of Said Ali al-Shihri... Known as Abu Sufian Kadhdhaab Matrook, Also Known as Sa'id Ali Jabir al-Khathim al-Shihri, Also Known as... January 23, 2003, I hereby determine that the individual known as Said Ali al- Shihri, and also known as...

  14. Shear thinning and shear thickening of a confined suspension of vesicles

    Science.gov (United States)

    Nait Ouhra, A.; Farutin, A.; Aouane, O.; Ez-Zahraouy, H.; Benyoussef, A.; Misbah, C.

    2018-01-01

    Widely regarded as an interesting model system for studying flow properties of blood, vesicles are closed membranes of phospholipids that mimic the cytoplasmic membranes of red blood cells. In this study we analyze the rheology of a suspension of vesicles in a confined geometry: the suspension, bound by two planar rigid walls on each side, is subject to a shear flow. Flow properties are then analyzed as a function of shear rate γ ˙, the concentration of the suspension ϕ , and the viscosity contrast λ =ηin/ηout , where ηin and ηout are the fluid viscosities of the inner and outer fluids, respectively. We find that the apparent (or effective viscosity) of the suspension exhibits both shear thinning (decreasing viscosity with shear rate) or shear thickening (increasing viscosity with shear rate) in the same concentration range. The shear thinning or thickening behaviors appear as subtle phenomena, dependant on viscosity contrast λ . We provide physical arguments on the origins of these behaviors.

  15. Recent benthic foraminifera and sedimentary facies distribution of the Abu Dhabi (United Arab Emirates) coastline

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.

    2014-05-01

    The distribution of benthic foraminifera and sedimentary facies from Recent coastline environments adjacent to the coastline of Abu Dhabi (UAE) was studied in detail with the aim to: 1) provide reliable analogs for understanding and interpreting the depositional environment of ancient shallow-marine sediments from the UAE; 2) assess any modifications in the distribution of benthic environments and sedimentary facies in an area affected by significant anthropogenic activities - particular construction and land reclamation. A total of 100 sea-floor sediment samples were collected in different shallow-marine sedimentary environments (nearshore shelf, beach-front, channels, ooid shoals, lagoon and mangals) close to the coastline of Abu Dhabi Island. Where possible, we revisited the sampling sites used in several studies conducted in the middle of last century (prior to any significant anthropogenic activities) to assess temporal changes in Recent benthic foraminifera and sedimentary facies distribution during the last 50 years. Five foraminiferal assemblages were recognized in the studied area. Species with a porcellaneous test mainly belonging to the genera Quinqueloculina, Triloculina, Spiroloculina, Sigmoilinita are common in all studied areas. Larger benthic foraminifera Peneroplis and Spirolina are particularly abundant in samples collected on seaweed. Hyaline foraminifera mostly belonging to the genera Elphidium, Ammonia, Bolivina and Rosalina are also common together with Miliolidae in the nearshore shelf and beach front. Agglutinated foraminifera (Clavulina, Textularia, Ammobaculites and Reophax) are present in low percentages. The species belonging to the genera Ammobaculites and Reophax are present only in the finest grain samples particularly in lagoons and mangal environments and have not been reported previously in the studied area. The majority of the ooid shoal sediments, the coarser sediments of the beach-front and samples collected in dredged channels

  16. KAJIAN TERJEMAHAN AL-QUR’AN (Studi Tarjamah al-Qur’an Basa Jawi “Assalam” Karya Abu Taufiq S.)

    OpenAIRE

    Indrati, Anisah

    2016-01-01

    This article examines the translation of the Koran in the Java language with title Kitab al-Qur'an Tarjamah Basa Jawi "Assalaam" by H. Abu Taufiq S. The focus of study in this article is to disclose the background and motivation of the writing of Tarjamah Qur 'an Basa Jawi "Assalaam", revealing the methods used and analyze the advantages and disadvantages of the Book Tarjamah Qur'an Basa Jawi "Assalaam". In addition this article also reveals the community's response to the study of the Koran ...

  17. International knowledge mobility and urban development in rapidly globalizing areas: building global hubs for talent in Dubai and Abu Dhabi

    OpenAIRE

    Ewers, Michael

    2016-01-01

    This paper examines the processes through which the United Arab Emirates’ (UAE) cities of Abu Dhabi and Dubai attract and integrate knowledge workers into their labor markets. It focuses on how the UAE has acquired the human capital to create post-oil economies, deploying its oil windfalls into massive urban development strategies in order to create global hubs for talent. More significantly, it analyzes how the UAE’s strategies and frameworks for attracting global knowle...

  18. Monitoring vegetation change in Abu Dhabi Emirate from 1996 to 2000 and 2004 using Landsat Satellite Imagery

    International Nuclear Information System (INIS)

    Starbuck, M.J.; Tamayo, J.

    2007-01-01

    In the fall of 2001, a study was initiated to investigate vegetation changes in the Abu Dhabi Emirates. The vast majority of vegetation present in the region is irrigated and analysis of vegetation change will support groundwater investigations in the region by indicating areas of increased water use. Satellite-based imaging systems provide a good source of data for such an analysis. The recent analysis was completed between February and November 2002 using Landsat 5 Thematic Mapper satellite imagery acquired in 1996 and Landsat 7 Enhanced Thematic Mapper Plus imagery acquired in 2000. These assessments were augmented in 2004with the study of Landsat 7 imagery acquired in early 2004. The total area of vegetation for each of seven study areas was calculated using the Normalized Difference Vegetation Index (NDVI) technique. Multiband image classification was used to differentiate general vegetation types. Change analysis consisted of simple NDVI image differencing and post-classification change matrices. Measurements of total vegetation are for the Abu Dhabi Emirate indicate an increase from 77,200 hectares in 1996 to 162,700 hectares in 2000 (110% increase). Based on comparison with manual interpretation of satellite imagery, the amount of under-reporting of irrigated land is estimated at about 15% of the actual area. From the assessment of 2004 Landset imagery, it was found that the growth of irrigated vegetation in most areas of Emirate had stabilized and had actually slightly decreased in some cases. The decreases are probably due to variability in the measurement technique and not due to actual decreases in area of vegetation. (author)

  19. Shear strength of non-shear reinforced concrete elements

    DEFF Research Database (Denmark)

    Hoang, Cao linh

    1997-01-01

    The paper deals with the shear strength of prestressed hollow-core slabs determined by the theory of plasticity. Two failure mechanisms are considered in order to derive the solutions.In the case of sliding failure in a diagonal crack, the shear strength is determined by means of the crack sliding...

  20. Seasonal variations in the biochemical composition of some common seaweed species from the coast of Abu Qir Bay, Alexandria, Egypt

    OpenAIRE

    Khairy, Hanan M.; El-Shafay, Shimaa M.

    2013-01-01

    Variations in protein, carbohydrate, lipid, ash, moisture, fatty acid and aminoacid contents of the seaweeds Ulva lactuca Linnaeus (Chlorophyta),Jania rubens (Linnaeus) J.V. Lamouroux and Pterocladia capillacea (S.G. Gmelin) Bornet(Rhodophyta) were studied seasonally from spring to autumn 2010. The seaweeds were collected from a rocky site near Boughaz El-Maadya on the coast of Abu Qir Bay east of Alexandria, Egypt. Remarkable seasonal variations were recorded in the levels of the studied pa...

  1. Kajian Termodinamika Adsorpsi Hibrida Merkapto-Silika dari Abu Sekam Padi Terhadap Ion Co(II

    Directory of Open Access Journals (Sweden)

    Dwi Rasy Mujiyanti

    2017-03-01

    Full Text Available AbstrakTelah dilakukan penelitian tentang kajian termodinamika adsorpsi hibrida merkapto-silika dari abu sekam padi terhadap ion Co(II. Penelitian ini bertujuan untuk menentukan kapasitas dan energi adsorpsi hibrida merkapto-silika (HMS dan silika gel (SG terhadap ion Co(II. Pada penelitian ini, silika gel dibuat menggunakan natrium silikat dari abu sekam padi. Selanjutnya, senyawa organik 3-(trimetoksisilil-1-propantiol diimobilisasi pada SG menghasilkan HMS. Adsorben dikarakterisasi menggunakan difraktometer sinar-X dan spektrofotometer FTIR. Larutan Co(II kemudian dikontakkan dengan SG dan HMS pada variasi pH, waktu, dan konsentrasi awal. Hasil penelitian kapasitas adsorpsi yang diperoleh HMS hampir tiga kali lebih besar dibandingkan dengan SG, dengan besarnya kapasitas adsorpsi masing-masing yaitu 250,00 mg/g dan 90,91 mg/g. Sedangkan energi adsorpsi yang diperoleh adalah 51,69 KJ/mol untuk SG, dan 23,65 KJ/mol untuk HMS.Kata kunci : sekam padi, hibrida merkapto-silika, adsorpsi, ion Co(IIAbstractA research on the study of the thermodynamics of adsorption mercapto-silica hybrid from rice husk ash to the ions Co (II has been done. This study aims to determine capacity and energy adsorption of hybrid mercapto-silica (HMS and silica gel (SG to the ions Co (II . In this study, silica gel was made using sodium silicate from rice husk ash. Furthermore, the organic compound 3-(trimethoxysilil -1-prophantiol immobilized on SG to HMS produced. Adsorbents were characterized using X-ray diffraction and FTIR spectrophotometer. Solution of Co (II is then contacted with the SG and HMS at the variation of pH, time , and initial concentration. The results obtained by HMS adsorption capacity is almost three times larger than the SG, the magnitude of adsorption capacity of each is 250.00 mg / g and 90.91 mg / g . While the adsorption energy obtained is 51.69 KJ / mol for SG , and 23.65 KJ / mol for HMS.Keywords : rice husk, mercapto-silica hybrid , adsorption

  2. Small Ruminant Production System Efficiency under Abu-Dhabi, United Arab Emirates Arid Land Conditions

    Directory of Open Access Journals (Sweden)

    Eihab Fathelrahman

    2014-12-01

    Full Text Available Sheep and goat production systems in the United Arab Emirates (UAE operate under scarce natural resource constraints. A cross-sectional survey that covered 661 mixed farms, including major sheep and goat production, was conducted in the three regions of Abu Dhabi Emirate (Al-Ain, Western Region and Abu Dhabi city during 2012. A Cobb-Douglas, double-logarithmic stochastic frontier production function and maximum likelihood estimation were applied to estimate important economic derivatives and the associated risk of small ruminant production in this arid area. The highest impact of an input on the output level was found to be labor for raising sheep and alfalfa grass for raising goats. Both labor and alfalfa variables were found to be overutilized for sheep and goat production, respectively. Overall, the results indicate that average technical efficiency is 0.62 for raising sheep and only 0.34 for raising goats in the study area. Technical efficiency analysis included measuring the frequency of farms at each level of estimated technical efficiency in the range between zero and one. Zero for the technical efficiency coefficient indicates a lack of technical efficiency in resource use. The results of this study indicated that only 1% of the sheep farms show a technical efficiency coefficient of 0.25 or less; the same can be said for 41% of goat producers. However, these technical efficiencies were found to be more than 0.75 for 12% and 5% of the sheep and goat farms, respectively. Overall, goat farming in the UAE was found to be less efficient than sheep production. The results also indicated that flock size and type of breed were the most influential factors relative to other factors, and both show a positive relationship with technical efficiency. Other than flock size, factors, such as owners’ years of experience and management practices, were found to be more influential on goat farming system efficiency relative to sheep farming.

  3. Continuous shear - a method for studying material elements passing a stationary shear plane

    DEFF Research Database (Denmark)

    Lindegren, Maria; Wiwe, Birgitte; Wanheim, Tarras

    2003-01-01

    circumferential groove. Normally shear in metal forming processes is of another nature, namely where the material elements move through a stationary shear zone, often of small width. In this paper a method enabling the simulation of this situation is presented. A tool for continuous shear has beeen manufactured...... and tested with AlMgSil and copper. The sheared material has thereafter been tested n plane strain compression with different orientation concerning the angle between the shear plane and the compression direction....

  4. Restoration and Preservation of Engraved Limestone Blocks Discovered in Abu Mousa Excavation, Suez - Egypt

    Directory of Open Access Journals (Sweden)

    Nabil A. Abd El-Tawab BADER

    2013-03-01

    Full Text Available A lot of engraved limestone blocks were discovered at Awlad Abu Musa (east of Suez, Egypt in 1995/2007 by Supreme Council of Antiquities. The stone blocks were seriously affected by archaeological environments during burial environment in agriculture land. They were covered with thick clay layer with soil particles that disfigured them and hid their inscriptions. Prior to the conservation intervention, the materials were characterized by X-ray diffraction, optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, Chemical analyses of ground water and microbiological study. After the material characterization, the conservation and restoration of the stone blocks were carried out including cleaning, consolidation, reduction of salts, Re-jointing, restoration and completion of lost parts. After that the blocks were exhibited in Suez museum.

  5. Separate structure of two branches of sheared slab ηi mode and effects of plasma rotation shear in weak magnetic shear region

    International Nuclear Information System (INIS)

    Jiquan Li; Kishimoto, Y.; Tuda, T.

    2000-01-01

    The separate structure of two branches of the sheared slab η i mode near the minimum-q magnetic surface is analysed and the effects of plasma rotation shears are considered in the weak magnetic shear region. Results show that the separation condition depends on the non-monotonous q profile and the deviation of rational surface from the minimum-q surface. Furthermore, it is found that the diamagnetic rotation shear may suppress the perturbation of the sheared slab η i mode at one side of the minimum-q surface, the poloidal rotation shear from the sheared E-vector x B-vector flow has a similar role to the slab mode structure when it possesses a direction same as the diamagnetic shear. A plausible interrelation between the separate structures of the two branches of the sheared slab mode and the discontinuity or gap of the radially global structure of the drift wave near the minimum-q surface observed in the toroidal particle simulation (Kishimoto Y et al 1998 Plasma Phys. Control. Fusion 40 A663) is discussed. It seems to support such a viewpoint: the double or/and global branches of the sheared slab η i mode near the minimum-q surface may become a bridge to connect the radially global structures of the drift wave at two sides of the minimum-q surface and the discontinuity may originate from the separate structures of these slab modes for a flatter q profile. (author)

  6. The brittle-viscous-plastic evolution of shear bands in the South Armorican Shear Zone

    Science.gov (United States)

    Bukovská, Zita; Jeřábek, Petr; Morales, Luiz F. G.; Lexa, Ondrej; Milke, Ralf

    2014-05-01

    Shear bands are microscale shear zones that obliquely crosscut an existing anisotropy such as a foliation. The resulting S-C fabrics are characterized by angles lower than 45° and the C plane parallel to shear zone boundaries. The S-C fabrics typically occur in granitoids deformed at greenschist facies conditions in the vicinity of major shear zones. Despite their long recognition, mechanical reasons for localization of deformation into shear bands and their evolution is still poorly understood. In this work we focus on microscale characterization of the shear bands in the South Armorican Shear Zone, where the S-C fabrics were first recognized by Berthé et al. (1979). The initiation of shear bands in the right-lateral South Armorican Shear Zone is associated with the occurrence of microcracks crosscutting the recrystallized quartz aggregates that define the S fabric. In more advanced stages of shear band evolution, newly formed dominant K-feldspar, together with plagioclase, muscovite and chlorite occur in the microcracks, and the shear bands start to widen. K-feldspar replaces quartz by progressively bulging into the grain boundaries of recrystallized quartz grains, leading to disintegration of quartz aggregates and formation of fine-grained multiphase matrix mixture. The late stages of shear band development are marked by interconnection of fine-grained white mica into a band that crosscuts the original shear band matrix. In its extremity, the shear band widening may lead to the formation of ultramylonites. With the increasing proportion of shear band matrix from ~1% to ~12%, the angular relationship between S and C fabrics increases from ~30° to ~40°. The matrix phases within shear bands show differences in chemical composition related to distinct evolutionary stages of shear band formation. The chemical evolution is well documented in K-feldspar, where the albite component is highest in porphyroclasts within S fabric, lower in the newly formed grains within

  7. Structure, Aboveground Biomass, and Soil Characterization of Avicennia marina in Eastern Mangrove Lagoon National Park, Abu Dhabi

    Science.gov (United States)

    Alsumaiti, Tareefa Saad Sultan

    Mangrove forests are national treasures of the United Arab Emirates (UAE) and other arid countries with limited forested areas. Mangroves form a crucial part of the coastal ecosystem and provide numerous benefits to society, economy, and especially the environment. Mangrove trees, specifically Avicennia marina, are studied in their native habitat in order to characterize their population structure, aboveground biomass, and soil properties. This study focused on Eastern Mangrove Lagoon National Park in Abu Dhabi, which was the first mangrove protected area to be designated in UAE. In situ measurements were collected to estimate Avicennia marina status, mortality rate (%), height (m), crown spread (m), stem number, diameter at breast height (cm), basal area (m), and aboveground biomass (t ha-1 ). Small-footprint aerial light detection and ranging (LIDAR) data acquired by UAE were processed to characterize mangrove canopy height and aboveground biomass density. This included extraction of LIDAR-derived height percentile statistics, segmentation of the forest into structurally homogenous units, and development of regression relationships between in situ reference and remote sensing data using a machine learning approach. An in situ soil survey was conducted to examine the soils' physical and chemical properties, fertility status, and organic matter. The data of soil survey were used to create soil maps to evaluate key characteristics of soils, and their influence on Avicennia marina in Eastern Mangrove Lagoon National Park. The results of this study provide new insights into Avicennia marina canopy population, structure, aboveground biomass, and soil properties in Abu Dhabi, as data in such arid environments is lacking. This valuable information can help in managing and preserving this unique ecosystem.

  8. Facies and sedimentary environments of the Abu Qada Formation at Gabal El-Gunna, Southeastern Sinai, Egypt

    Directory of Open Access Journals (Sweden)

    Tarek Y.M.A. El-Hariri

    2012-06-01

    Full Text Available The biostratigraphy, microfacies association, mineralogical interferences, depositional environments and geochemical properties of the Abu Qada Formation, which exposed at Gabal El-Gunna Southeastern Sinai, Egypt were delineated. It belongs to the planktonic foraminiferal Whiteinella archaeocretacea Zone of the Late Cenomanian-Early Turonian and consists of calcareous shale and limestone. The calcareous shale facies is characterized by chlorite, smectite and illite with high concentration of P2O5, Zn, Ni, V, and Cr. The carbonate rocks are characterized by foraminiferal wakestone and bioclastic grainstone. These microfacies associations are characterized by barite with high content of Sr. The facies types with faunal contents, geochemical and mineralogical studies suggest a restricted to shelf lagoon open circulation environment.

  9. Shear Capacity of C-Shaped and L-Shaped Angle Shear Connectors.

    Directory of Open Access Journals (Sweden)

    Farzad Tahmasbi

    Full Text Available This paper investigates the behaviour of C-shaped and L-shaped angle shear connectors embedded in solid concrete slabs. An effective finite element model is proposed to simulate the push out tests of these shear connectors that encompass nonlinear material behaviour, large displacement and damage plasticity. The finite element models are validated against test results. Parametric studies using this nonlinear model are performed to investigate the variations in concrete strength and connector dimensions. The finite element analyses also confirm the test results that increasing the length of shear connector increases their shear strength proportionately. It is observed that the maximum stress in L-shaped angle connectors takes place in the weld attachment to the beam, whereas in the C-shaped angle connectors, it is in the attached leg. The location of maximum concrete compressive damage is rendered in each case. Finally, a new equation for prediction of the shear capacity of C-shaped angle connectors is proposed.

  10. Shear Capacity of C-Shaped and L-Shaped Angle Shear Connectors

    Science.gov (United States)

    Tahmasbi, Farzad; Maleki, Shervin; Shariati, Mahdi; Ramli Sulong, N. H.; Tahir, M. M.

    2016-01-01

    This paper investigates the behaviour of C-shaped and L-shaped angle shear connectors embedded in solid concrete slabs. An effective finite element model is proposed to simulate the push out tests of these shear connectors that encompass nonlinear material behaviour, large displacement and damage plasticity. The finite element models are validated against test results. Parametric studies using this nonlinear model are performed to investigate the variations in concrete strength and connector dimensions. The finite element analyses also confirm the test results that increasing the length of shear connector increases their shear strength proportionately. It is observed that the maximum stress in L-shaped angle connectors takes place in the weld attachment to the beam, whereas in the C-shaped angle connectors, it is in the attached leg. The location of maximum concrete compressive damage is rendered in each case. Finally, a new equation for prediction of the shear capacity of C-shaped angle connectors is proposed. PMID:27478894

  11. Plasticity Approach to Shear Design

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1998-01-01

    The paper presents some plastic models for shear design of reinforced concrete beams. Distinction is made between two shear failure modes, namely web crushing and crack sliding. The first mentioned mode is met in beams with large shear reinforcement degrees. The mode of crack sliding is met in non......-shear reinforced beams as well as in lightly shear reinforced beams. For such beams the shear strength is determined by the recently developed crack sliding model. This model is based upon the hypothesis that cracks can be transformed into yield lines, which have lower sliding resistance than yield lines formed...... in uncracked concrete. Good agree between theory and tests has been found.Keywords: dsign, plasticity, reinforced concrete, reinforcement, shear, web crushing....

  12. Turbulence suppression by E x B shear in JET optimized shear pulses

    International Nuclear Information System (INIS)

    Beer, M.A.; Budny, R.V.; Challis, C.D.; Conway, G.

    2000-01-01

    The authors calculate microinstability growth rates in JET optimized shear plasmas with a comprehensive gyrofluid model, including sheared E x B flows, trapped electrons, and all dominant ion species in realistic magnetic geometry. They find good correlation between E x B shear suppression of microinstabilities and both the formation and collapse of the internal transport barrier

  13. Shear Strains, Strain Rates and Temperature Changes in Adiabatic Shear Bands

    Science.gov (United States)

    1980-05-01

    X14A. It has been found that when bainitic and martensitic steels are sheared adiabatically, a layer of material within ths shear zone is altezed and...Sooiety for Metals, Metals Park, Ohio, 1978, pp. 148-0. 21 TABLE II SOLID-STATE TRANSFORMATIONS IN BAINITIC STEEL TRANSFORMATION TRANSFORMATION...shear, thermoplastic, plasticity, plastic deformation, armor, steel IL AnSRACT ( -=nba asoa.tm a naeoesM iN faity by bleak n bet/2972 Experiments

  14. Characterization of historic mortars and earthen building materials in Abu Dhabi Emirate, UAE

    International Nuclear Information System (INIS)

    Marcus, Benjamin L

    2012-01-01

    The Abu Dhabi Authority for Culture and Heritage (ADACH) is responsible for the conservation and management of historic buildings and archaeological sites in the Emirate. Laboratory analysis has been critical for understanding the composition of historic materials and establishing appropriate conservation treatments across a wide variety of building types, ranging from Iron Age earthen archaeological sites to late-Islamic stone buildings. Analysis was carried out on historic sites in Al Ain, Delma Island and Liwa Oasis using techniques such as micro-x-ray fluorescence (MXRF), scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM-EDX), polarized light microscopy (PLM), and x-ray diffraction (XRD). Testing was conducted through consultant laboratories and in collaboration with local universities. The initial aim of the analysis was to understand historic earthen materials and to confirm the suitability of locally sourced clays for the production of mud bricks and plasters. Another important goal was to characterize materials used in historic stone buildings in order to develop repair mortars, renders and grouts.

  15. 141 ©sakarya üniversitesi ilahiyat fakültesi dergisi 14 / 2006, s. 141-157 arap dili ve belagatı EBÛ HİLÂL EL -‘ASKERÎ’YE GÖRE LAFIZ VE ANLAM Halim ÖZNURHAN * LAFZ AND MANA ACCORDING TO ABU HILAL AL-ASKARI

    OpenAIRE

    ÖZNURHAN, Halim

    2006-01-01

    Problem of lafz (word or sentence) and mana (meaning) discussed by the Arab critics. Abu Hilal al-Askari, one of them, takes division between lafz and mana and discusses each one separately. Although Abu Hilal al-Askari does not devote a specific chapter to discussion of lafz and mana, he does examine them in various chapters of the Kitab as-Sinaatayn. He also discussed several aspects, problems and defects of lafz and mana.:

  16. Relative viscosity of emulsions in simple shear flow: Temperature, shear rate, and interfacial tension dependence

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Se Bin; Lee, Joon Sang [Dept. of Mechanical Engineering, Yonsei Unversity, Seoul (Korea, Republic of)

    2015-08-15

    We simulate an emulsion system under simple shear rates to analyze its rheological characteristics using the lattice Boltzmann method (LBM). We calculate the relative viscosity of an emulsion under a simple shear flow along with changes in temperature, shear rate, and surfactant concentration. The relative viscosity of emulsions decreased with an increase in temperature. We observed the shear-thinning phenomena, which is responsible for the inverse proportion between the shear rate and viscosity. An increase in the interfacial tension caused a decrease in the relative viscosity of the decane-in-water emulsion because the increased deformation caused by the decreased interfacial tension significantly influenced the wall shear stress.

  17. Shear banding, discontinuous shear thickening, and rheological phase transitions in athermally sheared frictionless disks

    Science.gov (United States)

    Vâgberg, Daniel; Olsson, Peter; Teitel, S.

    2017-05-01

    We report on numerical simulations of simple models of athermal, bidisperse, soft-core, massive disks in two dimensions, as a function of packing fraction ϕ , inelasticity of collisions as measured by a parameter Q , and applied uniform shear strain rate γ ˙. Our particles have contact interactions consisting of normally directed elastic repulsion and viscous dissipation, as well as tangentially directed viscous dissipation, but no interparticle Coulombic friction. Mapping the phase diagram in the (ϕ ,Q ) plane for small γ ˙, we find a sharp first-order rheological phase transition from a region with Bagnoldian rheology to a region with Newtonian rheology, and show that the system is always Newtonian at jamming. We consider the rotational motion of particles and demonstrate the crucial importance that the coupling between rotational and translational degrees of freedom has on the phase structure at small Q (strongly inelastic collisions). At small Q , we show that, upon increasing γ ˙, the sharp Bagnoldian-to-Newtonian transition becomes a coexistence region of finite width in the (ϕ ,γ ˙) plane, with coexisting Bagnoldian and Newtonian shear bands. Crossing this coexistence region by increasing γ ˙ at fixed ϕ , we find that discontinuous shear thickening can result if γ ˙ is varied too rapidly for the system to relax to the shear-banded steady state corresponding to the instantaneous value of γ ˙.

  18. Analysis of the Shear Behavior of Stubby Y-Type Perfobond Rib Shear Connectors for a Composite Frame Structure.

    Science.gov (United States)

    Kim, Sang-Hyo; Kim, Kun-Soo; Lee, Do-Hoon; Park, Jun-Seung; Han, Oneil

    2017-11-22

    Shear connectors are used in steel beam-concrete slabs of composite frame and bridge structures to transfer shear force according to design loads. The existing Y-type perfobond rib shear connectors are designed for girder slabs of composite bridges. Therefore, the rib and transverse rebars of the conventional Y-type perfobond rib shear connectors are extremely large for the composite frames of building structures. Thus, this paper proposes stubby Y-type perfobond rib shear connectors, redefining the existing connectors, for composite frames of building structures; these were used to perform push-out tests. These shear connectors have relatively small ribs compared to the conventional Y-type perfobond rib shear connectors. To confirm the shear resistance of these stubby shear connectors, we performed an experiment by using transverse rebars D13 and D16. The results indicate that these shear connectors have suitable shear strength and ductility for application in composite frame structures. The shear strengths obtained using D13 and D16 were not significantly different. However, the ductility of the shear connectors with D16 was 45.1% higher than that of the shear connectors with D13.

  19. Comparison of direct shear and simple shear responses of municipal solid waste in USA

    KAUST Repository

    Fei, Xunchang; Zekkos, Dimitrios

    2017-01-01

    Although large-size simple shear (SS) testing of municipal solid waste (MSW) may arguably provide a more realistic estimate of the shear strength (τ ) of MSW than the most commonly used direct shear (DS) testing, a systematic comparison between

  20. Semiconductor laser shearing interferometer

    International Nuclear Information System (INIS)

    Ming Hai; Li Ming; Chen Nong; Xie Jiaping

    1988-03-01

    The application of semiconductor laser on grating shearing interferometry is studied experimentally in the present paper. The method measuring the coherence of semiconductor laser beam by ion etching double frequency grating is proposed. The experimental result of lens aberration with semiconductor laser shearing interferometer is given. Talbot shearing interferometry of semiconductor laser is also described. (author). 2 refs, 9 figs

  1. Comparison of direct shear and simple shear responses of municipal solid waste in USA

    KAUST Repository

    Fei, Xunchang

    2017-10-25

    Although large-size simple shear (SS) testing of municipal solid waste (MSW) may arguably provide a more realistic estimate of the shear strength (τ ) of MSW than the most commonly used direct shear (DS) testing, a systematic comparison between the shear responses of MSW obtained from the two testing methods is lacking. In this study, a large-size shear device was used to test identical MSW specimens sampled in USA in DS and SS. Eight DS tests and 11 SS tests were conducted at vertical effective stresses of 50–500 kPa. The stress–displacement response of MSW in SS testing was hyperbolic and a maximum shear stress was reached, whereas a maximum shear stress was not reached in most DS tests. The τ, effective friction angle (ϕ ′) and cohesion (c ′) of MSW were obtained from DS and SS tests by using a displacement failure criterion of 40 mm. τ in SS testing was found to be equal to or lower than τ in DS testing with ratios of τ between 73 and 101%. SS testing resulted in higher ϕ ′ but lower c ′ than DS testing. The shear strength parameters were lower than those obtained in previous studies from DS tests at 55 mm displacement.

  2. Experimental investigations into the shear behavior of self-compacting RC beams with and without shear reinforcement

    Directory of Open Access Journals (Sweden)

    Ammar N. HANOON

    2014-12-01

    Full Text Available Self-compacting concrete (SCC is a new generation of high-performance concrete, known for its excellent deformability and high resistance to segregation and bleeding. Nonetheless, SCC may be incapable of resisting shear because the shear resistance mechanisms of this concrete are uncertain, especially the aggregate interlock mechanism. This uncertainty is attributed to the fact that SCC contains a smaller amount of coarse aggregates than normal concrete (NC does. This study focuses on the shear strength of self-compacting reinforced concrete (RC beams with and without shear reinforcement. A total of 16 RC beam specimens was manufactured and tested in terms of shear span-to-depth ratio and flexural and shear reinforcement ratio. The test results were compared with those of the shear design equations developed by ACI, BS, CAN and NZ codes. Results show that an increase in web reinforcement enhanced cracking strength and ultimate load. Shear-tension failure was the control failure in all tested beams.

  3. Confocal microscopy of colloidal dispersions in shear flow using a counter-rotating cone-plate shear cell

    International Nuclear Information System (INIS)

    Derks, Didi; Wisman, Hans; Blaaderen, Alfons van; Imhof, Arnout

    2004-01-01

    We report on novel possibilities for studying colloidal suspensions in a steady shear field in real space. Fluorescence confocal microscopy is combined with the use of a counter-rotating cone-plate shear cell. This allows imaging of individual particles in the bulk of a sheared suspension in a stationary plane. Moreover, this plane of zero velocity can be moved in the velocity gradient direction while keeping the shear rate constant. The colloidal system under study consists of rhodamine labelled PMMA spheres in a nearly density and refractive index matched mixture of cyclohexylbromide and cis-decalin. We show measured flow profiles in both the fluid and the crystalline phase and find indications for shear banding in the case of a sheared crystal. Furthermore, we show that, thanks to the counter-rotating principle of the cone-plate shear cell, a layer of particles in the bulk of a sheared crystalline suspension can be imaged for a prolonged time, with the result that their positions can be tracked

  4. Comparing photo modeling methodologies and techniques: the instance of the Great Temple of Abu Simbel

    Directory of Open Access Journals (Sweden)

    Sergio Di Tondo

    2013-10-01

    Full Text Available After fifty years from the Salvage of the Abu Simbel Temples it has been possible to experiment the contemporary photo-modeling tools beginning from the original data of the photogrammetrical survey carried out in the 1950s. This produced a reflection on “Image Based” methods and modeling techniques, comparing strict 3d digital photogrammetry with the latest Structure From Motion (SFM systems. The topographic survey data, the original photogrammetric stereo couples, the points coordinates and their representation in contour lines, allowed to obtain a model of the monument in his configuration before the moving of the temples. The impossibility to carry out a direct survey led to touristic shots to create SFM models to use for geometric comparisons.

  5. Excited waves in shear layers

    Science.gov (United States)

    Bechert, D. W.

    1982-01-01

    The generation of instability waves in free shear layers is investigated. The model assumes an infinitesimally thin shear layer shed from a semi-infinite plate which is exposed to sound excitation. The acoustical shear layer excitation by a source further away from the plate edge in the downstream direction is very weak while upstream from the plate edge the excitation is relatively efficient. A special solution is given for the source at the plate edge. The theory is then extended to two streams on both sides of the shear layer having different velocities and densities. Furthermore, the excitation of a shear layer in a channel is calculated. A reference quantity is found for the magnitude of the excited instability waves. For a comparison with measurements, numerical computations of the velocity field outside the shear layer were carried out.

  6. Observations of the atmospheric boundary layer height over Abu Dhabi, United Arab Emirates: Investigating boundary layer climatology in arid regions

    Science.gov (United States)

    Marzooqi, Mohamed Al; Basha, Ghouse; Ouarda, Taha B. M. J.; Armstrong, Peter; Molini, Annalisa

    2014-05-01

    Strong sensible heat fluxes and deep turbulent mixing - together with marked dustiness and a low substrate water content - represent a characteristic signature in the boundary layer over hot deserts, resulting in "thicker" mixing layers and peculiar optical properties. Beside these main features however, desert ABLs present extremely complex local structures that have been scarcely addressed in the literature, and whose understanding is essential in modeling processes such as the transport of dust and pollutants, and turbulent fluxes of momentum, heat and water vapor in hyper-arid regions. In this study, we analyze a continuous record of observations of the atmospheric boundary layer (ABL) height from a single lens LiDAR ceilometer operated at Masdar Institute Field Station (24.4oN, 54.6o E, Abu Dhabi, United Arab Emirates), starting March 2013. We compare different methods for the estimation of the ABL height from Ceilometer data such as, classic variance-, gradient-, log gradient- and second derivation-methods as well as recently developed techniques such as the Bayesian Method and Wavelet covariance transform. Our goal is to select the most suited technique for describing the climatology of the ABL in desert environments. Comparison of our results with radiosonde observations collected at the nearby airport of Abu Dhabi indicate that the WCT and the Bayesian method are the most suitable tools to accurately identify the ABL height in all weather conditions. These two methods are used for the definition of diurnal and seasonal climatologies of the boundary layer conditional to different atmospheric stability classes.

  7. Shear strength of non-shear reinforced concrete elements

    DEFF Research Database (Denmark)

    Hoang, Cao linh

    1997-01-01

    is based upon the hypothesis that cracks can be transformed into yield lines, which have lower sliding resistance than yield lines formed in uncracked concrete.Proposals have been made on how the derived standard solutions may be applied to more complicated cases, such as continuous beams, beams......The report deals with the shear strength of statically indeterminate reinforced concrete beams without shear reinforcement. Solutions for a number of beams with different load and support conditions have been derived by means of the crack sliding model developed by Jin- Ping Zhang.This model...

  8. Experiments on sheet metal shearing

    OpenAIRE

    Gustafsson, Emil

    2013-01-01

    Within the sheet metal industry, different shear cutting technologies are commonly used in several processing steps, e.g. in cut to length lines, slitting lines, end cropping etc. Shearing has speed and cost advantages over competing cutting methods like laser and plasma cutting, but involves large forces on the equipment and large strains in the sheet material.Numerical models to predict forces and sheared edge geometry for different sheet metal grades and different shear parameter set-ups a...

  9. Experimental observation of shear thickening oscillation

    DEFF Research Database (Denmark)

    Nagahiro, Shin-ichiro; Nakanishi, Hiizu; Mitarai, Namiko

    2013-01-01

    We report experimental observations of the shear thickening oscillation, i.e. the spontaneous macroscopic oscillation in the shear flow of severe shear thickening fluid. Using a density-matched starch-water mixture, in the cylindrical shear flow of a few centimeters flow width, we observed...

  10. Isolation of keratinophilic fungi from the soil of islands of Greater Tunb, Abu-Musa and Sirri, Persian Gulf, Iran

    Directory of Open Access Journals (Sweden)

    Mohsen Nosratabadi

    2017-06-01

    Full Text Available Background and Purpose: Keratinophilic fungi are among the important groups of fungi living in the soil. This study aimed to isolate and identify keratinophilic fungi from the soil of three Iranian islands, namely Greater Tunb, Abu Musa, and Sirri, located in the Persian Gulf using morphological and molecular (polymerase chain reaction methods. Materials and Methods: In this study, a total of 60 soil samples were collected from the three islands of Greater Tunb, Abu Musa, and Sirri. The samples were analyzed for the presence of the keratinophilic fungi using a hair baiting technique. Furthermore, the identification of keratinophilic fungi was accomplished through the employment of molecular and sequencing techniques. Results: A total of 130 fungal isolates, including 11 genera with 24 species, were collected. Accordingly, Chrysosporium tropicum (24;18.5%, C. keratinophilum (17; 13.1%,  Chrysosporium  species (15; 11.5%, Aspergillus  species ( 8;6.1%, Aspergillus flavus (8; 6.1%, Penicillium  species (8;6.1%, Alternaria spp ( 6; 4.6%, Phoma  species (5;  3.8%, Aphanoascus verrucosus (4;3.1%, Fusarium chlamydosporum (4; 3.1%, Aspergillus trreus (4;3.1%, Acremonium  species (4; 3.1%, and other fungi( 23; 17.8 % isolates were identified . All isolates of keratinophilic fungi were isolated from the soils with the pH range of 7-9. Conclusion: The results of this study contributed towards a better conceptualization of the incidence pattern of keratinophilic fungi in the regions of Iran. Given that no study has investigated this issue, the findings of the present study can be beneficial for the management of public health surveillance, physicians, and epidemiologists.  

  11. Shear behaviour of reinforced phyllite concrete beams

    International Nuclear Information System (INIS)

    Adom-Asamoah, Mark; Owusu Afrifa, Russell

    2013-01-01

    Highlights: ► Phyllite concrete beams often exhibited shear with anchorage bond failure. ► Different shear design provisions for reinforced phyllite beams are compared. ► Predicted shear capacity of phyllite beams must be modified by a reduction factor. -- Abstract: The shear behaviour of concrete beams made from phyllite aggregates subjected to monotonic and cyclic loading is reported. First diagonal shear crack load of beams with and without shear reinforcement was between 42–58% and 42–92% of the failure loads respectively. The phyllite concrete beams without shear links had lower post-diagonal cracking shear resistance compared to corresponding phyllite beams with shear links. As a result of hysteretic energy dissipation, limited cyclic loading affected the stiffness, strength and deformation of the phyllite beams with shear reinforcement. Generally, beams with and without shear reinforcement showed anchorage bond failure in addition to the shear failure due to high stress concentration near the supports. The ACI, BS and EC codes are conservative for the prediction of phyllite concrete beams without shear reinforcement but they all overestimate the shear strength of phyllite concrete beams with shear reinforcement. It is recommended that the predicted shear capacity of phyllite beams reinforced with steel stirrups be modified by a reduction factor of 0.7 in order to specify a high enough safety factor on their ultimate strength. It is also recommended that susceptibility of phyllite concrete beams to undergo anchorage bond failure is averted in design by the provision of greater anchorage lengths than usually permitted.

  12. To determine the slow shearing rate for consolidation drained shear box tests

    Science.gov (United States)

    Jamalludin, Damanhuri; Ahmad, Azura; Nordin, Mohd Mustaqim Mohd; Hashim, Mohamad Zain; Ibrahim, Anas; Ahmad, Fauziah

    2017-08-01

    Slope failures always occur in Malaysia especially during the rainy seasons. They cause damage to properties and fatalities. In this study, a total of 24 one dimensional consolidation tests were carried out on soil samples taken from 16 slope failures in Penang Island and in Baling, Kedah. The slope failures in Penang Island are within the granitic residual soil while in Baling, Kedah they are situated within the sedimentary residual soil. Most of the disturbed soil samples were taken at 100mm depth from the existing soil surface while some soil samples were also taken at 400, 700 and 1000mm depths from the existing soil surface. They were immediately placed in 2 layers of plastic bag to prevent moisture loss. Field bulk density tests were also carried out at all the locations where soil samples were taken. The field bulk density results were later used to re-compact the soil samples for the consolidation tests. The objective of the research is to determine the slow shearing rate to be used in consolidated drained shear box for residual soils taken from slope failures so that the effective shear strength parameters can be determined. One dimensional consolidation tests were used to determine the slow shearing rate. The slow shearing rate found in this study to be used in the consolidated drained shear box tests especially for Northern Malaysian residual soils was 0.286mm/minute.

  13. Gametogenesis and spawning of Spirobranchus tetraceros (Polychaeta, Serpulidae in Abu Kir Bay, Egypt

    Directory of Open Access Journals (Sweden)

    S. A. SELIM

    2005-06-01

    Full Text Available The serpulid polychaete Spirobranchus tetraceros of Red Sea / Indo-pacific origin, recently has succeeded to establish a foothold in Alexandria Mediterranean waters. Worms were monthly scraped from submerged iron substrates at Abu Kir Bay during the period December 2000 – November 2001. Both light and TEM were used to study gametogenesis and time of spawning of S. tetraceros.Gametogenesis was asynchronous and oogenesis could be divided into two previtellogenic, two vitellogenic and a spawning stage. Oocyte development took about 8 months, from October to June. Spawning occurred from late May - early June until October. Thus S. tetraceros is a long period spawner. The maximum diameter of ripe oocyte is 78 mm. The spermatogenic phase could be divided into three stages: spermatogonia, spermatocytes and spermatids (including spermatozoa. The duration of sperm development took about 8 months. Spermatocytes persist from October to March. By March the sperms grew rapidly until they became spermatozoa in May. The sperm could be considered ect-aquasperm with regard to its fertilization biology.

  14. Sheared Electroconvective Instability

    Science.gov (United States)

    Kwak, Rhokyun; Pham, Van Sang; Lim, Kiang Meng; Han, Jongyoon

    2012-11-01

    Recently, ion concentration polarization (ICP) and related phenomena draw attention from physicists, due to its importance in understanding electrochemical systems. Researchers have been actively studying, but the complexity of this multiscale, multiphysics phenomenon has been limitation for gaining a detailed picture. Here, we consider electroconvective(EC) instability initiated by ICP under pressure-driven flow, a scenario often found in electrochemical desalinations. Combining scaling analysis, experiment, and numerical modeling, we reveal unique behaviors of sheared EC: unidirectional vortex structures, its size selection and vortex propagation. Selected by balancing the external pressure gradient and the electric body force, which generates Hagen-Poiseuille(HP) flow and vortical EC, the dimensionless EC thickness scales as (φ2 /UHP)1/3. The pressure-driven flow(or shear) suppresses unfavorably-directed vortices, and simultaneously pushes favorably-directed vortices with constant speed, which is linearly proportional to the total shear of HP flow. This is the first systematic characterization of sheared EC, which has significant implications on the optimization of electrodialysis and other electrochemical systems.

  15. Fifty years of shear zones

    Science.gov (United States)

    Graham, Rodney

    2017-04-01

    We are here, of course, because 1967 saw the publication of John Ramsay's famous book. Two years later a memorable field trip from Imperial College to the Outer Hebrides saw John on a bleak headland on the coast of North Uist where a relatively undeformed metadolerite within Lewisian (Precambrian) gneisses contained ductile shear zones with metamorphic fabrics in amphibolite facies. One particular outcrop was very special - a shear zone cutting otherwise completely isotropic, undeformed metadolerite, with an incremental foliation starting to develop at 45° to the deformation zone, and increasing in intensity as it approached the shear direction. Here was proof of the process of simple shear under ductile metamorphic conditions - the principles of simple shear outlined in John Ramsay's 1967 book clearly visible in nature, and verified by Ramsay's mathematical proofs in the eventual paper (Ramsay and Graham, 1970). Later work on the Lewisian on the mainland of Scotland, in South Harris, in Africa, and elsewhere applied Ramsay's simple shear principles more liberally, more imprecisely and on larger scale than at Caisteal Odair, but in retrospect it documented what seems now to be the generality of mid and lower crustal deformation. Deep seismic reflection data show us that on passive margins hyper-stretched continental crust (whether or not cloaked by Seaward Dipping Reflectors) seems to have collapsed onto the mantle. Crustal faults mostly sole out at or above the mantle - so the Moho is a detachment- an 'outer marginal detachment', if you like, and, of course, it must be a ductile shear. On non-volcanic margins this shear zone forms the first formed ocean floor before true sea floor spreading gets going to create real oceanic crust. Gianreto Manatschal, Marcel Lemoine and others realised that the serpentinites described in parts of the Alps are exposed remnants of this ductile shear zone. Associated ophicalcite breccias tell of sea floor exposure, while high

  16. High strength semi-active energy absorbers using shear- and mixedmode operation at high shear rates

    Science.gov (United States)

    Becnel, Andrew C.

    This body of research expands the design space of semi-active energy absorbers for shock isolation and crash safety by investigating and characterizing magnetorheological fluids (MRFs) at high shear rates ( > 25,000 1/s) under shear and mixed-mode operation. Magnetorheological energy absorbers (MREAs) work well as adaptive isolators due to their ability to quickly and controllably adjust to changes in system mass or impact speed while providing fail-safe operation. However, typical linear stroking MREAs using pressure-driven flows have been shown to exhibit reduced controllability as impact speed (shear rate) increases. The objective of this work is to develop MREAs that improve controllability at high shear rates by using pure shear and mixed shear-squeeze modes of operation, and to present the fundamental theory and models of MR fluids under these conditions. A proof of concept instrument verified that the MR effect persists in shear mode devices at shear rates corresponding to low speed impacts. This instrument, a concentric cylinder Searle cell magnetorheometer, was then used to characterize three commercially available MRFs across a wide range of shear rates, applied magnetic fields, and temperatures. Characterization results are presented both as flow curves according to established practice, and as an alternate nondimensionalized analysis based on Mason number. The Mason number plots show that, with appropriate correction coefficients for operating temperature, the varied flow curve data can be collapsed to a single master curve. This work represents the first shear mode characterization of MRFs at shear rates over 10 times greater than available with commercial rheometers, as well as the first validation of Mason number analysis to high shear rate flows in MRFs. Using the results from the magnetorheometer, a full scale rotary vane MREA was developed as part of the Lightweight Magnetorheological Energy Absorber System (LMEAS) for an SH-60 Seahawk helicopter

  17. Nasr Hamid Abu Zayd and the foundation of his hermeneutics: A critical review of the attitude that the Quran is the product of culture

    Directory of Open Access Journals (Sweden)

    Halilović Seid

    2017-01-01

    Full Text Available In the cognitive stage of religious traditions, science, in the light of the authority of religious revelation and reason, was dominant in relation to culture, which means that it was possible to determine the true value of different cultures using scientific knowledge. Nowadays, the completely opposite approach is gaining in popularity. Namely, when they discovered the fundamental weaknesses of empiristic definition of science, postmodern philosophers started more vocally saying that culture actually has a crucial influence on the method and internal science structure. Thus, science loses its cognitive independence and becomes the product of culture. In other words, each culture creates a separate scientific knowledge in accordance with its other cognitive layers and needs of the members of that culture. Among the Muslim reformist thinkers, influential Nasr Hamid Abu Zayd wrote in a most comprehensive and thorough manner about the text of the Quran undergoing the influence of culture from the time of life of t he Prophet Muhammad. He explained that the interpreter necessarily has a crucial role in forming the meaning of a text and that the meaning of the text will not be determined on its own until the hermeneutical position of the person reading and interpreting it is taken into consideration. Abu Zayd believed that the primal meaning of the Quran was conditioned by cultural and historic contexts of the time when the Quran appeared and that meaning was no longer credible. However, according to his opinion, the essence of the Quran message will be discovered using hermeneutics, when we harmonize the text with our contemporary cultural realities. With his pioneering attitude, Abu Zayd broke all ontological and metaphysical principles of mystical hermeneutics in the traditional cognitive environment of Islam. The renowned representatives of Islamic mystical heritage insisted that essential and inner meanings of the Quran text are in no way

  18. A Piezoelectric Shear Stress Sensor

    Science.gov (United States)

    Kim, Taeyang; Saini, Aditya; Kim, Jinwook; Gopalarathnam, Ashok; Zhu, Yong; Palmieri, Frank L.; Wohl, Christopher J.; Jiang, Xiaoning

    2016-01-01

    In this paper, a piezoelectric sensor with a floating element was developed for shear stress measurement. The piezoelectric sensor was designed to detect the pure shear stress suppressing effects of normal stress generated from the vortex lift-up by applying opposite poling vectors to the: piezoelectric elements. The sensor was first calibrated in the lab by applying shear forces and it showed high sensitivity to shear stress (=91.3 +/- 2.1 pC/Pa) due to the high piezoelectric coefficients of PMN-33%PT (d31=-1330 pC/N). The sensor also showed almost no sensitivity to normal stress (less than 1.2 pC/Pa) because of the electromechanical symmetry of the device. The usable frequency range of the sensor is 0-800 Hz. Keywords: Piezoelectric sensor, shear stress, floating element, electromechanical symmetry

  19. The dynamics of a shear band

    Science.gov (United States)

    Giarola, Diana; Capuani, Domenico; Bigoni, Davide

    2018-03-01

    A shear band of finite length, formed inside a ductile material at a certain stage of a continued homogeneous strain, provides a dynamic perturbation to an incident wave field, which strongly influences the dynamics of the material and affects its path to failure. The investigation of this perturbation is presented for a ductile metal, with reference to the incremental mechanics of a material obeying the J2-deformation theory of plasticity (a special form of prestressed, elastic, anisotropic, and incompressible solid). The treatment originates from the derivation of integral representations relating the incremental mechanical fields at every point of the medium to the incremental displacement jump across the shear band faces, generated by an impinging wave. The boundary integral equations (under the plane strain assumption) are numerically approached through a collocation technique, which keeps into account the singularity at the shear band tips and permits the analysis of an incident wave impinging a shear band. It is shown that the presence of the shear band induces a resonance, visible in the incremental displacement field and in the stress intensity factor at the shear band tips, which promotes shear band growth. Moreover, the waves scattered by the shear band are shown to generate a fine texture of vibrations, parallel to the shear band line and propagating at a long distance from it, but leaving a sort of conical shadow zone, which emanates from the tips of the shear band.

  20. Simulations of Granular Particles Under Cyclic Shear

    Science.gov (United States)

    Royer, John; Chaikin, Paul

    2012-02-01

    We perform molecular dynamics (MD) simulations of spherical grains subjected to cyclic, quasi-static shear in a 3D parallelepiped shear cell. This virtual shear cell is constructed out of rough, bumpy walls in order to minimize wall-induced ordering and has an open top surface to allow the packing to readily dilate or compact. Using a standard routine for MD simulations of frictional grains, we simulate over 1000 shear cycles, measuring grain displacements, the local packing density and changes in the contact network. Varying the shear amplitude and the friction coefficient between grains, we map out a phase diagram for the different types of behavior exhibited by these sheared grains. With low friction and high enough shear, the grains can spontaneously order into densely packed crystals. With low shear and increasing friction the packing remains disordered, yet the grains arrange themselves into configurations which exhibit limit cycles where all grains return to the same position after each full shear cycle. At higher shear and friction there is a transition to a diffusive state, where grains continue rearrange and move throughout the shear cell.

  1. CAT LIDAR wind shear studies

    Science.gov (United States)

    Goff, R. W.

    1978-01-01

    The studies considered the major meteorological factors producing wind shear, methods to define and classify wind shear in terms significant from an aircraft perturbation standpoint, the significance of sensor location and scan geometry on the detection and measurement of wind shear, and the tradeoffs involved in sensor performance such as range/velocity resolution, update frequency and data averaging interval.

  2. Shear flow effect on ion temperature gradient vortices in plasmas with sheared magnetic field

    DEFF Research Database (Denmark)

    Chakrabarti, N.; Juul Rasmussen, J.

    1999-01-01

    The effect of velocity shear on ion temperature gradient (ITG) driven vortices in a nonuniform plasma in a curved, sheared magnetic field is investigated. In absence of parallel ion dynamics, vortex solutions for the ITG mode are studied analytically. It is shown that under certain conditions...... and ultimately lead to a dominating monopolar form. The effects of magnetic shear indicate it may destroy these structures. (C) 1999 American Institute of Physics....

  3. Friction of Shear-Fracture Zones

    Science.gov (United States)

    Riikilä, T. I.; Pylväinen, J. I.; Åström, J.

    2017-12-01

    A shear fracture of brittle solids under compression undergoes a substantial evolution from the initial microcracking to a fully formed powder-filled shear zone. Experiments covering the entire process are relatively easy to conduct, but they are very difficult to investigate in detail. Numerically, the large strain limit has remained a challenge. An efficient simulation model and a custom-made experimental device are employed to test to what extent a shear fracture alone is sufficient to drive material to spontaneous self-lubrication. A "weak shear zone" is an important concept in geology, and a large number of explanations, specific for tectonic conditions, have been proposed. We demonstrate here that weak shear zones are far more general, and that their emergence only demands that a microscopic, i.e., fragment-scale, stress relaxation mechanism develops during the fracture process.

  4. Magnetorheological dampers in shear mode

    International Nuclear Information System (INIS)

    Wereley, N M; Cho, J U; Choi, Y T; Choi, S B

    2008-01-01

    In this study, three types of shear mode damper using magnetorheological (MR) fluids are theoretically analyzed: linear, rotary drum, and rotary disk dampers. The damping performance of these shear mode MR dampers is characterized in terms of the damping coefficient, which is the ratio of the equivalent viscous damping at field-on status to the damping at field-off status. For these three types of shear mode MR damper, the damping coefficient or dynamic range is derived using three different constitutive models: the Bingham–plastic, biviscous, and Herschel–Bulkley models. The impact of constitutive behavior on shear mode MR dampers is theoretically presented and compared

  5. IMAGE ANALYSIS FOR MODELLING SHEAR BEHAVIOUR

    Directory of Open Access Journals (Sweden)

    Philippe Lopez

    2011-05-01

    Full Text Available Through laboratory research performed over the past ten years, many of the critical links between fracture characteristics and hydromechanical and mechanical behaviour have been made for individual fractures. One of the remaining challenges at the laboratory scale is to directly link fracture morphology of shear behaviour with changes in stress and shear direction. A series of laboratory experiments were performed on cement mortar replicas of a granite sample with a natural fracture perpendicular to the axis of the core. Results show that there is a strong relationship between the fracture's geometry and its mechanical behaviour under shear stress and the resulting damage. Image analysis, geostatistical, stereological and directional data techniques are applied in combination to experimental data. The results highlight the role of geometric characteristics of the fracture surfaces (surface roughness, size, shape, locations and orientations of asperities to be damaged in shear behaviour. A notable improvement in shear understanding is that shear behaviour is controlled by the apparent dip in the shear direction of elementary facets forming the fracture.

  6. Design and implementation of a shearing apparatus for the experimental study of shear displacement in rocks

    Science.gov (United States)

    Moore, Johnathan; Crandall, Dustin; Gill, Magdalena; Brown, Sarah; Tennant, Bryan

    2018-04-01

    Fluid flow in the subsurface is not well understood in the context of "impermeable" geologic media. This is especially true of formations that have undergone significant stress fluctuations due to injection or withdrawal of fluids that alters the localized pressure regime. When the pressure regime is altered, these formations, which are often already fractured, move via shear to reduce the imbalance in the stress state. While this process is known to happen, the evolution of these fractures and their effects on fluid transport are still relatively unknown. Numerous simulation and several experimental studies have been performed that characterize the relationship between shearing and permeability in fractures; while many of these studies utilize measurements of fluid flow or the starting and ending geometries of the fracture to characterize shear, they do not characterize the intermediate stages during shear. We present an experimental apparatus based on slight modifications to a commonly available Hassler core holder that allows for shearing of rocks, while measuring the hydraulic and mechanical changes to geomaterials during intermediate steps. The core holder modification employs the use of semi-circular end caps and structural supports for the confining membrane that allow for free movement of the sheared material while preventing membrane collapse. By integrating this modified core holder with a computed tomography scanner, we show a new methodology for understanding the interdependent behavior between fracture structure and flow properties during intermediate steps in shearing. We include a case study of this device function which is shown here through shearing of a fractured shale core and simultaneous observation of the mechanical changes and evolution of the hydraulic properties during shearing.

  7. Mean wall-shear stress measurements using the micro-pillar shear-stress sensor MPS3

    International Nuclear Information System (INIS)

    Große, S; Schröder, W

    2008-01-01

    A new sensor to measure the mean turbulent wall-shear stress in turbulent flows is described. The wall-shear stress sensor MPS 3 has been tested in a well-defined fully developed turbulent pipe flow at Reynolds numbers Re b based on the bulk velocity U b and the pipe diameter D in the range of Re b = 10 000–20 000. The results demonstrate a convincing agreement of the mean wall-shear stress obtained with the new sensor technique with analytical and experimental results from the literature. The sensor device consists of a flexible micro-pillar that extends from the wall into the viscous sublayer. Bending due to the exerting fluid forces, the pillar-tip deflection serves as a measure for the local wall-shear stress. The sensor concept, calibration techniques, the achievable accuracy and error estimates, the fields of application and the sensor limits will be discussed. Furthermore, a first estimate of the pillar dynamic response will be derived showing the potential of the sensor to also measure the turbulent fluctuating wall-shear stress

  8. Microstructural evolution of a model, shear-banding micellar solution during shear startup and cessation.

    Science.gov (United States)

    López-Barrón, Carlos R; Gurnon, A Kate; Eberle, Aaron P R; Porcar, Lionel; Wagner, Norman J

    2014-04-01

    We present direct measurements of the evolution of the segmental-level microstructure of a stable shear-banding polymerlike micelle solution during flow startup and cessation in the plane of flow. These measurements provide a definitive, quantitative microstructural understanding of the stages observed during flow startup: an initial elastic response with limited alignment that yields with a large stress overshoot to a homogeneous flow with associated micellar alignment that persists for approximately three relaxation times. This transient is followed by a shear (kink) band formation with a flow-aligned low-viscosity band that exhibits shear-induced concentration fluctuations and coexists with a nearly isotropic band of homogenous, highly viscoelastic micellar solution. Stable, steady banding flow is achieved only after approximately two reptation times. Flow cessation from this shear-banded state is also found to be nontrivial, exhibiting an initial fast relaxation with only minor structural relaxation, followed by a slower relaxation of the aligned micellar fluid with the equilibrium fluid's characteristic relaxation time. These measurements resolve a controversy in the literature surrounding the mechanism of shear banding in entangled wormlike micelles and, by means of comparison to existing literature, provide further insights into the mechanisms driving shear-banding instabilities in related systems. The methods and instrumentation described should find broad use in exploring complex fluid rheology and testing microstructure-based constitutive equations.

  9. Inductive shearing of drilling pipe

    Science.gov (United States)

    Ludtka, Gerard M.; Wilgen, John; Kisner, Roger; Mcintyre, Timothy

    2016-04-19

    Induction shearing may be used to cut a drillpipe at an undersea well. Electromagnetic rings may be built into a blow-out preventer (BOP) at the seafloor. The electromagnetic rings create a magnetic field through the drillpipe and may transfer sufficient energy to change the state of the metal drillpipe to shear the drillpipe. After shearing the drillpipe, the drillpipe may be sealed to prevent further leakage of well contents.

  10. Non-homogeneous flow profiles in sheared bacterial suspensions

    Science.gov (United States)

    Samanta, Devranjan; Cheng, Xiang

    Bacterial suspensions under shear exhibit interesting rheological behaviors including the remarkable ``superfluidic'' state with vanishing viscosity at low shear rates. Theoretical studies have shown that such ``superfluidic'' state is linked with non-homogeneous shear flows, which are induced by coupling between nematic order of active fluids and hydrodynamics of shear flows. However, although bulk rheology of bacterial suspensions has been experimentally studied, shear profiles within bacterial suspensions have not been explored so far. Here, we experimentally investigate the flow behaviors of E. coli suspensions under planar oscillatory shear. Using confocal microscopy and PIV, we measure velocity profiles across gap between two shear plates. We find that with increasing shear rates, high-concentration bacterial suspensions exhibit an array of non-homogeneous flow behaviors like yield-stress flows and shear banding. We show that these non-homogeneous flows are due to collective motion of bacterial suspensions. The phase diagram of sheared bacterial suspensions is systematically mapped as functions of shear rates an bacterial concentrations. Our experiments provide new insights into rheology of bacterial suspensions and shed light on shear induced dynamics of active fluids. Chemical Engineering and Material Science department.

  11. Exponential Shear Flow of Linear, Entangled Polymeric Liquids

    DEFF Research Database (Denmark)

    Neergaard, Jesper; Park, Kyungho; Venerus, David C.

    2000-01-01

    A previously proposed reptation model is used to interpret exponential shear flow data taken on an entangled polystyrenesolution. Both shear and normal stress measurements are made during exponential shear using mechanical means. The model iscapable of explaining all trends seen in the data......, and suggests a novel analysis of the data. This analysis demonstrates thatexponential shearing flow is no more capable of stretching polymer chains than is inception of steady shear at comparableinstantaneous shear rates. In fact, all exponential shear flow stresses measured are bounded quantitatively...

  12. Far-from-equilibrium sheared colloidal liquids: Disentangling relaxation, advection, and shear-induced diffusion

    KAUST Repository

    Lin, Neil Y. C.

    2013-12-01

    Using high-speed confocal microscopy, we measure the particle positions in a colloidal suspension under large-amplitude oscillatory shear. Using the particle positions, we quantify the in situ anisotropy of the pair-correlation function, a measure of the Brownian stress. From these data we find two distinct types of responses as the system crosses over from equilibrium to far-from-equilibrium states. The first is a nonlinear amplitude saturation that arises from shear-induced advection, while the second is a linear frequency saturation due to competition between suspension relaxation and shear rate. In spite of their different underlying mechanisms, we show that all the data can be scaled onto a master curve that spans the equilibrium and far-from-equilibrium regimes, linking small-amplitude oscillatory to continuous shear. This observation illustrates a colloidal analog of the Cox-Merz rule and its microscopic underpinning. Brownian dynamics simulations show that interparticle interactions are sufficient for generating both experimentally observed saturations. © 2013 American Physical Society.

  13. Far-from-equilibrium sheared colloidal liquids: Disentangling relaxation, advection, and shear-induced diffusion

    KAUST Repository

    Lin, Neil Y. C.; Goyal, Sushmit; Cheng, Xiang; Zia, Roseanna N.; Escobedo, Fernando A.; Cohen, Itai

    2013-01-01

    Using high-speed confocal microscopy, we measure the particle positions in a colloidal suspension under large-amplitude oscillatory shear. Using the particle positions, we quantify the in situ anisotropy of the pair-correlation function, a measure of the Brownian stress. From these data we find two distinct types of responses as the system crosses over from equilibrium to far-from-equilibrium states. The first is a nonlinear amplitude saturation that arises from shear-induced advection, while the second is a linear frequency saturation due to competition between suspension relaxation and shear rate. In spite of their different underlying mechanisms, we show that all the data can be scaled onto a master curve that spans the equilibrium and far-from-equilibrium regimes, linking small-amplitude oscillatory to continuous shear. This observation illustrates a colloidal analog of the Cox-Merz rule and its microscopic underpinning. Brownian dynamics simulations show that interparticle interactions are sufficient for generating both experimentally observed saturations. © 2013 American Physical Society.

  14. Study of shear thickening behavior in colloidal suspensions

    Directory of Open Access Journals (Sweden)

    N Maleki Jirsaraee

    2015-01-01

    Full Text Available We studied the shear thickening behavior of the nano silica suspension (silica nanoparticles 12 nm in size suspended in ethylene glycol under steady shear. The critical shear rate for transition into shear thickening phase was determined at different concentrations and temperatures. The effect of temperature and concentration was studied on the shear thickening behavior. In silica suspension, it was observed that all the samples had a transition into shear thickening phase and also by increasing the temperature, critical shear rate increased and viscosity decreased. Our observations showed that movement in silica suspension was Brownian and temperature could cause a delay in transition into shear thickening phase. Yet, we observed that increasing the concentration would decrease critical shear rate and increase viscosity. Increasing temperature increased Brownian forces and increasing concentration increased hydrodynamic forces, confirming the contrast between these two forces for transition into shear thickening phase for the suspensions containing nano particles

  15. Comparative Review of Abu al-Tayyib al-Mutanabbi’s & Masu’d Sa’d Salman Odes

    Directory of Open Access Journals (Sweden)

    f Ishraqi

    2014-11-01

    This survey reviews similar contents of the two Divan using comparative aspect in Abu al-Tayyib and Masu’d Sa’d-i Salman’s poems. Several exemplifications show that Masu’d Sa’d-i Salman sometimes translated al-mutanbbi’s poets and used them artily. Sometimes however, we can find identical contents originating from connotation between the two poets, so they should not be considered as adoption or translation.

  16. New ceramic data from East Kalimantan : the cord-marked and red-slipped sherds of Liang Abu's layer 2 and Kalimantan's potter chronology

    International Nuclear Information System (INIS)

    Plutniak, S.; Agus Oktaviana, A.; Sugiyanto, B.; Chazine, J.M.; Ricaut, F.X.

    2014-01-01

    Archaeological research in the Liang Abu rock shelter (East Kalimantan) led to the discovery and analysis of a pottery assemblage including red-slipped, cord-marked and incised pottery sherds, radiocarbon dated to 1672 ± 21 BP and 1524 ± 22 BP. In order to discuss our findings we undertake a reappraisal of the pottery material and associated radiocarbon dates from archaeological sites on Borneo Island, which provide us with an appropriate framework for a comparative analysis. This allows us to to include the inland region of Kalimantan in the technological network of Neolithic Island South East Asia. (author)

  17. KATALIS HETEROGEN DARI ABU VULKANIK UNTUK PEMBUATAN BIODIESEL DARI MINYAK MIKROALGA 1,2 CHLORELLA Sp

    Directory of Open Access Journals (Sweden)

    Catur Rini Widyastuti

    2015-02-01

    Full Text Available Proses produksi biodiesel secara konvensional menggunakan bahan baku yang terbatas jumlahnya, proses yang rumit, dan banyaknya limbah yang dihasilkan menyebabkan produksi biodiesel dalam skala besar tidak dapat direalisasikan dengan mudah. Mikroalga merupakan sumber bahan alam terbarukan yang sangat potensial untuk produksi biodiesel karena kandungan minyaknya yang tinggi, kecepatannya tumbuh pada lahan yang terbatas, serta merupakan produk non-pangan. Salah satu jenis mikroalga dengan kandungan minyak yang relatif besar (28-32% berat kering adalah mikroalga Chlorella sp. Selain bahan baku, pemilihan proses yang lebih sederhana dan ekonomis perlu dikembangkan. Selama ini, proses produksi biodiesel konvensioanal banyak menghasilkan air limbah pada tahap pemisahan produk dari katalis yang larut dan produk samping yang dihasilkan. Oleh karena itu, untuk mengurangi limbah yang dihasilkan selama proses pemisahan tersebut, jenis katalis heterogen dapat digunakan untuk menggantikan katalis homogen alkali yang biasa digunakan. Katalis padat tersebut dapat disintesis dari abu vulkanik yang mengandung unsur-unsur seperti SiO2, Al2O3, Fe2O3, TiO2, MnO, CaO, MgO, Na2O, K2O, P2O5, serta beberapa elemen minor seperti Zr, Sr, dan V. Penelitian ini bertujuan untuk mengkaji jenis katalis dan aktivitasnya dalam reaksi transesterifikasi minyak mikroalga Chlorella sp menjadi biodiesel. Tahap awal penelitian yang dilakukan adalah preparasi minyak mikroalga yang akan digunakan untuk uji aktivitas katalis. Minyak mikroalga diperoleh dengan ekstraksi menggunakan metode maserasi menggunakan pelarut n-heksana. Rendemen minyak yang diperoleh sebesar 12,26%. Dari hasil uji GC-MS diketahui dua kandungan asam lemak terbesar dalam minyak mikroalga, yaitu Dodecanoic acid sebesar 59.52% dan n-Decanoic acid sebesar 12.64%. Selanjutnya minyak mikroalga direaksikan dengan metanol dengan rasio molar 1:6 menggunakan jenis katalis yang disintesis dari abu vulkanik. Preparasi katalis

  18. Onset of shear thinning in glassy liquids: Shear-induced small reduction of effective density.

    Science.gov (United States)

    Furukawa, Akira

    2017-01-01

    We propose a simple mechanism for describing the onset of shear thinning in a high-density glassy liquid. In a shear flow, along the compression axis, the overlap between neighboring particles is more enhanced than that at equilibrium, meaning that the "effective" size is reduced along this axis. On the other hand, along the extension axis perpendicular to the compression axis, the average structural configurations are stretched, but it does not indicate the expansion of the "effective" size itself. This asymmetric shear flow effect for particles results in a small reduction of the "effective" density. Because, in glass-forming liquids, the structural relaxation time τ_{α} strongly depends on the density ρ, even a very small reduction of the effective density should lead to a significant decrease of the relaxation time under shear flow. We predict that the crossover shear rate from Newtonian to non-Newtonian flow behaviors is given by γ[over ̇]_{c}=[ρ(∂τ_{α}/∂ρ)]^{-1}, which can be much smaller than 1/τ_{α} near the glass transition point. It is shown that this prediction is consistent with the results of molecular dynamics simulations.

  19. Effect of Boundary Condition on the Shear Behaviour of Rock Joints in the Direct Shear Test

    Science.gov (United States)

    Bahaaddini, M.

    2017-05-01

    The common method for determination of the mechanical properties of the rock joints is the direct shear test. This paper aims to study the effect of boundary condition on the results of direct shear tests. Experimental studies undertaken in this research showed that the peak shear strength is mostly overestimated. This problem is more pronounced for steep asperities and under high normal stresses. Investigation of the failure mode of these samples showed that tensile cracks are generated at the boundary of sample close to the specimen holders and propagated inside the intact materials. In order to discover the reason of observed failure mechanism in experiments, the direct shear test was simulated using PFC2D. Results of numerical models showed that the gap zone size between the upper and lower specimen holders has a significant effect on the shear mechanism. For the high gap size, stresses concentrate at the vicinity of the tips of specimen holders and result in generation and propagation of tensile cracks inside the intact material. However, by reducing the gap size, stresses are concentrated on asperities, and damage of specimen at its boundary is not observed. Results of this paper show that understanding the shear mechanism of rock joints is an essential step prior to interpreting the results of direct shear tests.

  20. Seismic data interpretation for hydrocarbon potential, for Safwa/Sabbar field, East Ghazalat onshore area, Abu Gharadig basin, Western Desert, Egypt

    Directory of Open Access Journals (Sweden)

    Naser A. Hameed El Redini

    2017-12-01

    Full Text Available Safwa/Sabbar oil field located in the East Ghazalat Concession in the proven and prolific Abu Gharadig basin, Western Desert, Egypt, and about 250 km to the southwest of Cairo, it’s located in the vicinity of several producing oil fields ranging from small to large size hydrocarbon accumulation, adjacent to the NW-SE trending major Abu Gharadig fault which is throwing to the Southwest.All the geological, “structure and stratigraphic” elements, have been identified after interpreting the recent high quality 3D seismic survey for prospect generation, evaluation and their relation to the hydrocarbon exploration.Synthetic seismograms have been carried out for all available wells to tie horizons to seismic data and to define the lateral variation characters of the beds.The analysis has been done using the suitable seismic attributes to understand the characteristics of different types of the reservoir formations, type of trap system, identify channels and faults, and delineating the stratigraphic plays of good reservoirs such as Eocene Apollonia Limestone, AR “F”, AR “G” members, Upper Bahariya, Jurassic Khatatba Sandstone, upper Safa and Lower Safa Sandstone.The top Cenomanian Bahariya level is the main oil reservoir in the Study area, which consist of Sandstone, Siltstone and Shale, the thickness is varying from 1 to 50 ft along the study area.In addition to Upper-Bahariya there are a good accessibility of hydrocarbon potential within the Jurassic Khatatba Sandstone and the Eocene Apollonia Limestone. More exploring of these reservoirs are important to increase productivity of Oil and/or Gas in the study area.

  1. Dilatancy of Shear Transformations in a Colloidal Glass

    Science.gov (United States)

    Lu, Y. Z.; Jiang, M. Q.; Lu, X.; Qin, Z. X.; Huang, Y. J.; Shen, J.

    2018-01-01

    Shear transformations, as fundamental rearrangement events operating in local regions, hold the key of plastic flow of amorphous solids. Despite their importance, the dynamic features of shear transformations are far from clear, which is the focus of the present study. Here, we use a colloidal glass under shear as the prototype to directly observe the shear-transformation events in real space. By tracing the colloidal-particle rearrangements, we quantitatively determine two basic properties of shear transformations: local shear strain and dilatation (or free volume). It is revealed that the local free volume undergoes a significantly temporary increase prior to shear transformations, eventually leading to a jump of local shear strain. We clearly demonstrate that shear transformations have no memory of the initial free volume of local regions. Instead, their emergence strongly depends on the dilatancy ability of these local regions, i.e., the dynamic creation of free volume. More specifically, the particles processing the high dilatancy ability directly participate in subsequent shear transformations. These results experimentally enrich Argon's statement about the dilatancy nature of shear transformations and also shed insight into the structural origin of amorphous plasticity.

  2. Rheometry-PIV of shear-thickening wormlike micelles.

    Science.gov (United States)

    Marín-Santibañez, Benjamín M; Pérez-Gonzalez, José; de Vargas, Lourdes; Rodríguez-Gonzalez, Francisco; Huelsz, Guadalupe

    2006-04-25

    The shear-thickening behavior of an equimolar semidilute aqueous solution of 40 mM/L cetylpyridinium chloride and sodium salicylate was studied in this work by using a combined method of rheometry and particle image velocimetry (PIV). Experiments were conducted at 27.5 degrees C with Couette, vane-bob, and capillary rheometers in order to explore a wide shear stress range as well as the effect of boundary conditions and time of flow on the creation and destruction of shear-induced structures (SIS). The use of the combined method of capillary rheometry with PIV allowed the detection of fast spatial and temporal variations in the flow kinematics, which are related to the shear-thickening behavior and the dynamics of the SIS but are not distinguished by pure rheometrical measurements. A rich-in-details flow curve was found for this solution, which includes five different regimes. Namely, at very low shear rates a Newtonian behavior was found, followed by a shear thinning one in the second regime. In the third, shear banding was observed, which served as a precursor of the SIS and shear-thickening. The fourth and fifth regimes in the flow curve were separated by a spurtlike behavior, and they clearly evidenced the existence of shear-thickening accompanied by stick-slip oscillations at the wall of the rheometer, which subsequently produced variations in the shear rate under shear stress controlled flow. Such a stick-slip phenomenon prevailed up to the highest shear stresses used in this work and was reflected in asymmetric velocity profiles with spatial and temporal variations linked to the dynamics of creation and breakage of the SIS. The presence of apparent slip at the wall of the rheometer provides an energy release mechanism which leads to breakage of the SIS, followed by their further reformation during the stick part of the cycles. In addition, PIV measurements allowed the detection of apparent slip at the wall, as well as mechanical failures in the bulk of the

  3. The Theatre of Cruelty: Dehumanization, Objectification & Abu Ghraib

    Directory of Open Access Journals (Sweden)

    Christiana Spens

    2014-09-01

    Full Text Available A clumsy pyramid of kneeling men, naked apart from the hoods over their heads, with a smiling, fair-headed woman and a grinning man with a moustache, wearing green cleaning gloves; a slight woman with a blank expression and a man on the floor, on a limp leash; a hooded, robed figure, standing on a box with his arms outstretched and a pose similar to the crucifixion, with sinister wires behind him, and otherwise blank surroundings.  A row of more hooded, naked men, forced to do sexual acts as a female prison guard (Lynndie England, tanned and wearing various shades of khaki, grins and does a thumbs up sign, pointing at him, her cigarette tilted and her expression not altogether different from Bonnie in 'Bonnie and Clyde. 'A man in uniform and a black beanie hat, sitting on an Iraqi prisoner. Another pyramid of naked detainees, with a man and women behind them, smiling arm in arm, as if they are standing by a caught wild boar or large fish, or a well-organised barbeque. The moustached man (Charles Graner, again smiling and giving a thumbs up sign, this time over a corpse, whose bloody eyes have been bandaged. A naked prisoner covering his ears, as several dogs bark at him, and soldiers watch on. Another prisoner chained to a bed-frame, with some underpants covering his face.  These infamous scenes, shown in the Abu Ghraib photographs, shocked many people, and the perpetrators of the torture depicted were condemned by the relevant authorities. They transformed from clandestine mementos of hidden violence to records of an international scandal and evidence of serious crime. Their meaning changed depending on who saw them, how they were interpreted, what reactions they provoked, and the rulings of the courts regarding the people involved. They went from being private victory shots, to an international public relations disaster, to evidence of breaking of the Geneva Convention.

  4. Behavior of Tilted Angle Shear Connectors

    Science.gov (United States)

    Khorramian, Koosha; Maleki, Shervin; Shariati, Mahdi; Ramli Sulong, N. H.

    2015-01-01

    According to recent researches, angle shear connectors are appropriate to transfer longitudinal shear forces across the steel-concrete interface. Angle steel profile has been used in different positions as L-shaped or C-shaped shear connectors. The application of angle shear connectors in tilted positions is of interest in this study. This study investigates the behaviour of tilted-shaped angle shear connectors under monotonic loading using experimental push out tests. Eight push-out specimens are tested to investigate the effects of different angle parameters on the ultimate load capacity of connectors. Two different tilted angles of 112.5 and 135 degrees between the angle leg and steel beam are considered. In addition, angle sizes and lengths are varied. Two different failure modes were observed consisting of concrete crushing-splitting and connector fracture. By increasing the size of connector, the maximum load increased for most cases. In general, the 135 degrees tilted angle shear connectors have a higher strength and stiffness than the 112.5 degrees type. PMID:26642193

  5. Behavior of Tilted Angle Shear Connectors.

    Directory of Open Access Journals (Sweden)

    Koosha Khorramian

    Full Text Available According to recent researches, angle shear connectors are appropriate to transfer longitudinal shear forces across the steel-concrete interface. Angle steel profile has been used in different positions as L-shaped or C-shaped shear connectors. The application of angle shear connectors in tilted positions is of interest in this study. This study investigates the behaviour of tilted-shaped angle shear connectors under monotonic loading using experimental push out tests. Eight push-out specimens are tested to investigate the effects of different angle parameters on the ultimate load capacity of connectors. Two different tilted angles of 112.5 and 135 degrees between the angle leg and steel beam are considered. In addition, angle sizes and lengths are varied. Two different failure modes were observed consisting of concrete crushing-splitting and connector fracture. By increasing the size of connector, the maximum load increased for most cases. In general, the 135 degrees tilted angle shear connectors have a higher strength and stiffness than the 112.5 degrees type.

  6. Periodic Viscous Shear Heating Instability in Fine-Grained Shear Zones: Possible Mechanism for Intermediate Depth Earthquakes and Slow Earthquakes?

    Science.gov (United States)

    Kelemen, P. B.; Hirth, G.

    2004-12-01

    Localized ductile shear zones with widths of cm to m are observed in exposures of Earth's shallow mantle (e.g., Kelemen & Dick JGR 95; Vissers et al. Tectonophys 95) and dredged from oceanic fracture zones (e.g., Jaroslow et al. Tectonophys 96). These are mylonitic (grain size 10 to 100 microns) and record mineral cooling temperatures from 1100 to 600 C. Pseudotachylites in a mantle shear zone show that shear heating temperatures can exceed the mantle solidus (e.g., Obata & Karato Tectonophys 95). Simple shear, recrystallization, and grain boundary sliding all decrease the spacing between pyroxenes, so olivine grain growth at lower stress is inhibited; thus, once formed, these shear zones do not "heal" on geological time scales. Reasoning that grain-size sensitive creep will be localized within these shear zones, rather than host rocks (grain size 1 to 10 mm), and inspired by the work of Whitehead & Gans (GJRAS 74), we thought these might undergo repeated shear heating instabilities. In this view, as elastic stress increases, the shear zone weakens via shear heating; rapid deformation of the weak shear zone releases most stored elastic stress; lower stress and strain rate coupled with diffusion of heat into host rocks leads to cooling and strengthening, after which the cycle repeats. We constructed a simple numerical model incorporating olivine flow laws for dislocation creep, diffusion creep, grain boundary sliding, and low T plasticity. We assumed that viscous deformation remains localized in shear zones, surrounded by host rocks undergoing elastic deformation. We fixed the velocity along one side of an elastic half space, and calculated stress due to elastic strain. This stress drives viscous deformation in a shear zone of specified width. Shear heating and thermal diffusion control temperature evolution in the shear zone and host rocks. A maximum of 1400 C (where substantial melting of peridotite would occur) is imposed. Grain size evolves during dislocation

  7. Effects of ExB velocity shear and magnetic shear on turbulence and transport in magnetic confinement devices

    International Nuclear Information System (INIS)

    Burrell, K.H.

    1996-11-01

    One of the scientific success stories of fusion research over the past decade is the development of the ExB shear stabilization model to explain the formation of transport barriers in magnetic confinement devices. This model was originally developed to explain the transport barrier formed at the plasma edge in tokamaks after the L (low) to H (high) transition. This concept has the universality needed to explain the edge transport barriers seen in limiter and divertor tokamaks, stellarators, and mirror machines. More recently, this model has been applied to explain the further confinement improvement from H (high)-mode to VH (very high)-mode seen in some tokamaks, where the edge transport barrier becomes wider. Most recently, this paradigm has been applied to the core transport barriers formed in plasmas with negative or low magnetic shear in the plasma core. These examples of confinement improvement are of considerable physical interest; it is not often that a system self-organizes to a higher energy state with reduced turbulence and transport when an additional source of free energy is applied to it. The transport decrease that is associated with ExB velocity shear effects also has significant practical consequences for fusion research. The fundamental physics involved in transport reduction is the effect of ExB shear on the growth, radial extent and phase correlation of turbulent eddies in the plasma. The same fundamental transport reduction process can be operational in various portions of the plasma because there are a number ways to change the radial electric field Er. An important theme in this area is the synergistic effect of ExB velocity shear and magnetic shear. Although the ExB velocity shear appears to have an effect on broader classes of microturbulence, magnetic shear can mitigate some potentially harmful effects of ExB velocity shear and facilitate turbulence stabilization

  8. Low-rise shear wall failure modes

    International Nuclear Information System (INIS)

    Farrar, C.R.; Hashimoto, P.S.; Reed, J.W.

    1991-01-01

    A summary of the data that are available concerning the structural response of low-rise shear walls is presented. This data will be used to address two failure modes associated with the shear wall structures. First, data concerning the seismic capacity of the shear walls with emphasis on excessive deformations that can cause equipment failure are examined. Second, data concerning the dynamic properties of shear walls (stiffness and damping) that are necessary to compute the seismic inputs to attached equipment are summarized. This case addresses the failure of equipment when the structure remains functional. 23 refs

  9. Application of Electrical Resistivity Tomography Technique for Characterizing Leakage Problem in Abu Baara Earth Dam, Syria

    Directory of Open Access Journals (Sweden)

    Walid Al-Fares

    2014-01-01

    Full Text Available Electrical Resistivity Tomography (ERT survey was carried out at Abu Baara earth dam in northwestern Syria, in order to delineate potential pathways of leakage occurring through the subsurface structure close to the dam body. The survey was performed along two straight measuring profiles of 715 and 430 m length in up- and downstream sides of the dam’s embankment. The analysis of the inverted ERT sections revealed the presence of fractured and karstified limestone rocks which constitute the shallow bedrock of the dam reservoir. Several subsurface structural anomalies were identified within the fractured bedrock, most of which are associated with probable karstic cavities, voids, and discontinuity features developed within the carbonates rocks. Moreover, results also showed the occurrence of a distinguished subsiding structure coinciding with main valley course. Accordingly, it is believed that the bedrock and the other detected features are the main potential causes of water leakage from the dam’s reservoir.

  10. Chirality-specific lift forces of helix under shear flows: Helix perpendicular to shear plane.

    Science.gov (United States)

    Zhang, Qi-Yi

    2017-02-01

    Chiral objects in shear flow experience a chirality-specific lift force. Shear flows past helices in a low Reynolds number regime were studied using slender-body theory. The chirality-specific lift forces in the vorticity direction experienced by helices are dominated by a set of helix geometry parameters: helix radius, pitch length, number of turns, and helix phase angle. Its analytical formula is given. The chirality-specific forces are the physical reasons for the chiral separation of helices in shear flow. Our results are well supported by the latest experimental observations. © 2016 Wiley Periodicals, Inc.

  11. Microstructure evolution of pure copper during a single pass of simple shear extrusion (SSE): role of shear reversal

    Energy Technology Data Exchange (ETDEWEB)

    Bagherpour, E., E-mail: e.bagherpour@semnan.ac.ir [Faculty of Metallurgical and Materials Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Department of Mechanical Engineering, Doshisha University, Kyotanabe, Kyoto 610–0394 (Japan); Qods, F., E-mail: qods@semnan.ac.ir [Faculty of Metallurgical and Materials Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Ebrahimi, R., E-mail: ebrahimy@shirazu.ac.ir [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Miyamoto, H., E-mail: hmiyamot@mail.doshisha.ac.jp [Department of Mechanical Engineering, Doshisha University, Kyotanabe, Kyoto 610–0394 (Japan)

    2016-06-01

    In the present paper the role of shear reversal on microstructure, texture and mechanical properties of pure copper during a single pass of the simple shear extrusion (SSE) process was investigated. For SSE processing an appropriate die with a linear die profile was designed and constructed, which imposes forward shear in the first half and reverse shear in the second half channels. Electron back-scattering diffraction (EBSD), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) were used to evaluate the microstructure of the deformed samples. The geometrical nature of this process imposes a distribution of strain results in the inhomogeneous microstructure and the hardness throughout the plane perpendicular to the extrusion direction. Strain reversal during the process results in a slight reduction in dislocation density, the hardness and mean disorientation angle of the samples, and an increase in the grain size. After a complete pass of SSE, dislocation density decreased by ~14% if compared to the middle of the process. This suggests that the dislocation annihilation occurred by the reversal of the shear strain. The simple shear textures were formed gradually and the strongest simple shear textures were observed on the middle of the SSE channel. The degree of the simple shear textures decreases with the distance from the middle plane where the shear is reversed, but the simple shear textures are still the major components after exit of the channel. Hardness variation was modeled by contributions from dislocation strengthening and grain boundary strengthening, where dislocation density is approximated by the misorientation angle of LAGBs which are regarded as dislocation cell boundaries. As a result, the hardness can be predicted successfully by the microstructural features, i.e. the low-angle boundaries, the mean misorientation angle and the fraction of high-angle grain boundaries.

  12. Modeling combined tension-shear failure of ductile materials

    International Nuclear Information System (INIS)

    Partom, Y

    2014-01-01

    Failure of ductile materials is usually expressed in terms of effective plastic strain. Ductile materials can fail by two different failure modes, shear failure and tensile failure. Under dynamic loading shear failure has to do with shear localization and formation of adiabatic shear bands. In these bands plastic strain rate is very high, dissipative heating is extensive, and shear strength is lost. Shear localization starts at a certain value of effective plastic strain, when thermal softening overcomes strain hardening. Shear failure is therefore represented in terms of effective plastic strain. On the other hand, tensile failure comes about by void growth under tension. For voids in a tension field there is a threshold state of the remote field for which voids grow spontaneously (cavitation), and the material there fails. Cavitation depends on the remote field stress components and on the flow stress. In this way failure in tension is related to shear strength and to failure in shear. Here we first evaluate the cavitation threshold for different remote field situations, using 2D numerical simulations with a hydro code. We then use the results to compute examples of rate dependent tension-shear failure of a ductile material.

  13. Role of E x B Shear and Magnetic Shear in the Formation of Transport Barriers in DIII-D

    International Nuclear Information System (INIS)

    Burrell, K.H.

    2005-01-01

    Development of the E x B shear stabilization model to explain the formation of transport barriers in magnetic confinement devices is a major achievement of fusion research. This concept has the universality needed to explain the H-mode edge transport barriers seen in limiter and divertor tokamaks, stellarators, and mirror machines; the broader edge transport barrier seen in VH-mode plasmas; and the core transport barriers formed in tokamaks with low or negative magnetic shear. These examples of confinement improvement are of considerable physical interest; it is not often that a system self-organizes to reduce transport when an additional source of free energy is applied to it. The transport decrease associated with E x B velocity shear is also of great practical benefit to fusion research. The fundamental physics involved in transport reduction is the effect of E x B shear on the growth, radial extent, and phase correlation of turbulent eddies in the plasma. The same basic transport reduction process can be operational in various portions of the plasma because there are a number of ways to change the radial electric field E r . An important theme in this area is the synergistic effect of E x B velocity shear and magnetic shear. Although the E x B velocity shear appears to have an effect on broader classes of microturbulence, magnetic shear can mitigate some potentially harmful effects of E x B velocity shear and facilitate turbulence stabilization. The experimental results on DIII-D and other devices are generally consistent with the basic theoretical models

  14. Focusing of Shear Shock Waves

    Science.gov (United States)

    Giammarinaro, Bruno; Espíndola, David; Coulouvrat, François; Pinton, Gianmarco

    2018-01-01

    Focusing is a ubiquitous way to transform waves. Recently, a new type of shock wave has been observed experimentally with high-frame-rate ultrasound: shear shock waves in soft solids. These strongly nonlinear waves are characterized by a high Mach number, because the shear wave velocity is much slower, by 3 orders of magnitude, than the longitudinal wave velocity. Furthermore, these waves have a unique cubic nonlinearity which generates only odd harmonics. Unlike longitudinal waves for which only compressional shocks are possible, shear waves exhibit cubic nonlinearities which can generate positive and negative shocks. Here we present the experimental observation of shear shock wave focusing, generated by the vertical motion of a solid cylinder section embedded in a soft gelatin-graphite phantom to induce linearly vertically polarized motion. Raw ultrasound data from high-frame-rate (7692 images per second) acquisitions in combination with algorithms that are tuned to detect small displacements (approximately 1 μ m ) are used to generate quantitative movies of gel motion. The features of shear shock wave focusing are analyzed by comparing experimental observations with numerical simulations of a retarded-time elastodynamic equation with cubic nonlinearities and empirical attenuation laws for soft solids.

  15. Direct Shear Behavior of Fiber Reinforced Concrete Elements

    Directory of Open Access Journals (Sweden)

    Hussein Al-Quraishi

    2018-01-01

    Full Text Available Improving the accuracy of load-deformation behavior, failure mode, and ultimate load capacity for reinforced concrete members subjected to in-plane loadings such as corbels, wall to foundation connections and panels need shear strength behavior to be included. Shear design in reinforced concrete structures depends on crack width, crack slippage and roughness of the surface of cracks. This paper illustrates results of an experimental investigation conducted to investigate the direct shear strength of fiber normal strength concrete (NSC and reactive powder concrete (RPC. The tests were performed along a pre-selected shear plane in concrete members named push-off specimens. The effectiveness of concrete compressive strength, volume fraction of steel fiber, and shear reinforcement ratio on shear transfer capacity were considered in this study. Furthermore, failure modes, shear stress-slip behavior, and shear stress-crack width behavior were also presented in this study. Tests’ results showed that volume fraction of steel fiber and compressive strength of concrete in NSC and RPC play a major role in improving the shear strength of concrete. As expectedly, due to dowel action, the shear reinforcement is the predominant factor in resisting the shear stress. The shear failure of NSC and RPC has the sudden mode of failure (brittle failure with the approximately linear behavior of shear stress-slip relationship till failure. Using RPC instead of NSC with the same amount of steel fibers in constructing the push-off specimen result in high shear strength. In NSC, shear strength influenced by the three major factors; crack surface friction, aggregate interlock and steel fiber content if present. Whereas, RPC has only steel fiber and cracks surface friction influencing the shear strength. Due to cementitious nature of RPC in comparisons with NSC, the RPC specimen shows greater cracks width. It is observed that the Mattock model gives very satisfactory

  16. Origins of Shear Jamming for Frictional Grains

    Science.gov (United States)

    Wang, Dong; Zheng, Hu; Ren, Jie; Dijksman, Joshua; Bares, Jonathan; Behringer, Robert

    2016-11-01

    Granular systems have been shown to be able to behave like solids, under shear, even when their densities are below the critical packing fraction for frictionless isotropic jamming. To understand such a phenomena, called shear jamming, the question we address here is: how does shear bring a system from a unjammed state to a jammed state, where the coordination number, Z, is no less than 3, the isotropic jamming point for frictional grains? Since Z can be used to distinguish jammed states from unjammed ones, it is vital to understand how shear increases Z. We here propose a set of three particles in contact, denoted as a trimer, as the basic unit to characterize the deformation of the system. Trimers, stabilized by inter-grain friction, fail under a certain amount of shear and bend to make extra contacts to regain stability. By defining a projection operator of the opening angle of the trimer to the compression direction in the shear, O, we see a systematically linear decrease of this quantity with respect to shear strain, demonstrating the bending of trimers as expected. In addition, the average change of O from one shear step to the next shows a good collapse when plotted against Z, indicating a universal behavior in the process of shear jamming. We acknowledge support from NSF DMR1206351, NASA NNX15AD38G, the William M. Keck Foundation and a RT-MRSEC Fellowship.

  17. Crosswind Shear Gradient Affect on Wake Vortices

    Science.gov (United States)

    Proctor, Fred H.; Ahmad, Nashat N.

    2011-01-01

    Parametric simulations with a Large Eddy Simulation (LES) model are used to explore the influence of crosswind shear on aircraft wake vortices. Previous studies based on field measurements, laboratory experiments, as well as LES, have shown that the vertical gradient of crosswind shear, i.e. the second vertical derivative of the environmental crosswind, can influence wake vortex transport. The presence of nonlinear vertical shear of the crosswind velocity can reduce the descent rate, causing a wake vortex pair to tilt and change in its lateral separation. The LES parametric studies confirm that the vertical gradient of crosswind shear does influence vortex trajectories. The parametric results also show that vortex decay from the effects of shear are complex since the crosswind shear, along with the vertical gradient of crosswind shear, can affect whether the lateral separation between wake vortices is increased or decreased. If the separation is decreased, the vortex linking time is decreased, and a more rapid decay of wake vortex circulation occurs. If the separation is increased, the time to link is increased, and at least one of the vortices of the vortex pair may have a longer life time than in the case without shear. In some cases, the wake vortices may never link.

  18. Sheared-root inocula of vesicular-arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Sylvia, D M; Jarstfer, A G

    1992-01-01

    For efficient handling, vesicular-arbuscular mycorrhizal fungi should be processed into small and uniform inocula; however, processing can reduce the inoculum density. In this article we describe the preparation and use of sheared-root inocula of Glomus spp. in which inoculum densities were increased during processing. Our objectives were to determine inoculum viability and density after shearing and to ascertain if the sheared inocula could be pelletized or used with a gel carrier. Root samples were harvested from aeroponic cultures, blotted dry, cut into 1-cm lengths, and sheared in a food processor for up to 80 s. After shearing, the inoculum was washed over sieves, and the propagule density in each fraction was determined. Sheared inocula were also encapsulated in carrageenan or used in a gel carrier. Shearing aeroponically produced root inocula reduced particle size. Propagule density increased with decreasing size fraction down to a size of 63 mum, after which propagule density decreased. The weighted-average propagule density of the inoculum was 135,380 propagules g (dry weight) of sheared root material. Sheared roots were encapsulated successfully in carrageenan, and the gel served as an effective carrier. Aeroponic root inoculum was stored dry at 4 degrees C for 23 months without significant reduction in propagule density; however, this material was not appropriate for shearing. Moist roots, useful for shearing, began to lose propagule density after 1 month of storage. Shearing proved to be an excellent method to prepare viable root inocula of small and uniform size, allowing for more efficient and effective use of limited inoculum supplies.

  19. Imaging Shear Strength Along Subduction Faults

    Science.gov (United States)

    Bletery, Quentin; Thomas, Amanda M.; Rempel, Alan W.; Hardebeck, Jeanne L.

    2017-11-01

    Subduction faults accumulate stress during long periods of time and release this stress suddenly, during earthquakes, when it reaches a threshold. This threshold, the shear strength, controls the occurrence and magnitude of earthquakes. We consider a 3-D model to derive an analytical expression for how the shear strength depends on the fault geometry, the convergence obliquity, frictional properties, and the stress field orientation. We then use estimates of these different parameters in Japan to infer the distribution of shear strength along a subduction fault. We show that the 2011 Mw9.0 Tohoku earthquake ruptured a fault portion characterized by unusually small variations in static shear strength. This observation is consistent with the hypothesis that large earthquakes preferentially rupture regions with relatively homogeneous shear strength. With increasing constraints on the different parameters at play, our approach could, in the future, help identify favorable locations for large earthquakes.

  20. Imaging shear strength along subduction faults

    Science.gov (United States)

    Bletery, Quentin; Thomas, Amanda M.; Rempel, Alan W.; Hardebeck, Jeanne L.

    2017-01-01

    Subduction faults accumulate stress during long periods of time and release this stress suddenly, during earthquakes, when it reaches a threshold. This threshold, the shear strength, controls the occurrence and magnitude of earthquakes. We consider a 3-D model to derive an analytical expression for how the shear strength depends on the fault geometry, the convergence obliquity, frictional properties, and the stress field orientation. We then use estimates of these different parameters in Japan to infer the distribution of shear strength along a subduction fault. We show that the 2011 Mw9.0 Tohoku earthquake ruptured a fault portion characterized by unusually small variations in static shear strength. This observation is consistent with the hypothesis that large earthquakes preferentially rupture regions with relatively homogeneous shear strength. With increasing constraints on the different parameters at play, our approach could, in the future, help identify favorable locations for large earthquakes.

  1. Elemen Kebangsawanan dalam Pemilihan Pemimpin: Analisis Kontekstual Pemilihan Saidina Abu Bakr, Muawiyyah serta Kesultanan Melayu

    Directory of Open Access Journals (Sweden)

    Mohd Haidhar Kamarzaman

    2013-12-01

    Full Text Available Pemilihan pemimpin negara dalam Islam merupakan tugas yang berat ini selaras dengan kepentingannya dilihat sebagai pengganti Rasulullah (s.a.w iaitu menyebarkan Islam dan mentadbir kelangsungan Islam. Namun yang menjadi fokus kepada penulisan ini adalah faktor kebangsawanan dalam pelantikan pemimpin dalam Islam. Kajian ini memfokuskan kepada sejarah bagaimana elemen kebangsawanan kaum Quraisy bagi Saidina Abu Bakar r.a menjadi faktor yang berpengaruh dalam pelantikan beliau sebagai khalifah Islam yang pertama, Muawiyyah sebagai pemimpin Bani Umayyah yang pertama dan kebangsawanan dalam pemilihan pemimpin di Tanah Melayu seterusnya merentasi perbahasannya ke Malaysia dari sudut pelantikan kesultanan dan pembesar melayu serta pelantikan Perdana Menteri yang mewakili era moden. Metodologi yang digunakan adalah kajian kepustakaan dengan merujuk segala karya-karya berkaitan perkara yang dibincangkan dalam kajian ini. Hasil kajian dalam penulisan ini adalah kebangsawanan merupakan satu faktor yang melengkapkan pemilihan pemimpin walaupun bukan satu syarat yang muktamad dalam Islam. Bahkan istilah kebangsawanan itu juga digunakan mengikut kesesuaian budaya setempat sebagaimana yang ditunjuki dalam dua konteks pemilhan khalifah Islam yang pertama, Muawiyyah dan Tanah Melayu seterusnya Malaysia.

  2. Application of a precipitation method for uranium recovery from abu-zaabal phosphoric acid plant, Egypt

    International Nuclear Information System (INIS)

    El-hazek, N.M.T.; Hussein, E.M.

    1995-01-01

    Current industrial recovery of uranium from 30% phosphoric acid-produced by the dihydrate process-is based on solvent extraction method. Uranium recovery from concentrated phosphoric acid (45-52% p o5 ) produced by evaporation of the 30% acid or directly produced by the hemihydrate process, by solvent extraction is difficult to apply in practice. In addition to possible contamination of the acid by the organic solvents and/or their deterioration. This paper investigates the possibility of applying a precipitation method (Weterings and Janssen, 1985) for uranium recovery from both low (28% P 2 O 5 ) and high (48% P 2 O 5 ) concentration phosphoric acids produced by abu-zaabal phosphoric acid plant (Abuzaabal fertilizers and chemicals Co., Egypt). The 28% acid produced by H 2 SO 4 dihydrate method and the 48% acid produced by evaporation of the 28% acid The applied precipitation method depends on using NH 4 F as a uranium precipitant from both low and high concentration phosphoric acids in presence of acetone as a dispersing agent. All the relevant factors have been studied

  3. The safety issue of roadside advertising – comparison of polish and abu dhabi regulations

    Directory of Open Access Journals (Sweden)

    Mackun Tomasz

    2017-01-01

    Full Text Available In Poland a large number of advertisements are located by the roadside. These ads do not support road traffic management and unlike the road marking system are not subject to any regulations. The advertiser’s goal is to communicate a message to as many recipients as possible. Drivers with different individual abilities, such as attention focusing, eye accommodation, speed of information processing, can be distracted, blinded or confused by the content and form of the advertising. There are elements of the road network, such as intersections, pedestrian crossings, road junctions etc. where the driver must assess the situation on the road, predict the behaviour of other users, make decisions and finally complete a manoeuvre. It all happens in a limited span of time when actions should be taken calmly with full attention. It is obvious that the attention of drivers, especially in those zones, should be focused on the task of driving. In this article, the authors present a perspective on selected national laws, and also quote Abu Dhabi’s advertising placement manual [1] as a good example of how to manage roadside advertising.

  4. Evaluating the impact of technology use in energy management in Abu Dhabi Distribution Company

    Energy Technology Data Exchange (ETDEWEB)

    Al Haddabi, A. [Abu Dhabi Distribution Co., Abu Dhabi (United Arab Emirates). Dept. of Power Network Development; El-Baz, H.; Gadalla, M. [American Univ. of Sharjah, Sharjah (United Arab Emirates). College of Engineering

    2009-07-01

    A decision support system (DSS) was used at the Abu Dhabi distribution company (ADDC) in the United Arab Emirates to help planners and managers choose and implement the most reliable and economic network configuration. The impact of using a Geographical Information System (GIS) and Distribution Management System (DMS) on the reliability and cost of alternative network-distribution systems was also examined. The study took into account reliability costs as well as maintenance and investment costs to achieve the optimal feeder automation plan for the best transmission-system reliability. The planning of a distribution system involves two aspects, notably reliability and capacity of the system to meet load growth. Examples of improving distribution network performance after implementing GIS and DMS technologies were presented. The system reliabilities were measured by the System Average Interruption Duration Index (SAIDI), System Average Interruption Frequency Index (SAIFI), and the Un-served KWh per Customer. The results showed that GIS and DMS technologies can improve system reliability indices by up to 45 per cent depending on the network architecture, with less than 10 per cent increase in related investment costs. 26 refs., 1 tab., 5 figs.

  5. Predicting Shear Transformation Events in Metallic Glasses

    Science.gov (United States)

    Xu, Bin; Falk, Michael L.; Li, J. F.; Kong, L. T.

    2018-03-01

    Shear transformation is the elementary process for plastic deformation of metallic glasses, the prediction of the occurrence of the shear transformation events is therefore of vital importance to understand the mechanical behavior of metallic glasses. In this Letter, from the view of the potential energy landscape, we find that the protocol-dependent behavior of shear transformation is governed by the stress gradient along its minimum energy path and we propose a framework as well as an atomistic approach to predict the triggering strains, locations, and structural transformations of the shear transformation events under different shear protocols in metallic glasses. Verification with a model Cu64 Zr36 metallic glass reveals that the prediction agrees well with athermal quasistatic shear simulations. The proposed framework is believed to provide an important tool for developing a quantitative understanding of the deformation processes that control mechanical behavior of metallic glasses.

  6. Thrombus Formation at High Shear Rates.

    Science.gov (United States)

    Casa, Lauren D C; Ku, David N

    2017-06-21

    The final common pathway in myocardial infarction and ischemic stroke is occlusion of blood flow from a thrombus forming under high shear rates in arteries. A high-shear thrombus forms rapidly and is distinct from the slow formation of coagulation that occurs in stagnant blood. Thrombosis at high shear rates depends primarily on the long protein von Willebrand factor (vWF) and platelets, with hemodynamics playing an important role in each stage of thrombus formation, including vWF binding, platelet adhesion, platelet activation, and rapid thrombus growth. The prediction of high-shear thrombosis is a major area of biofluid mechanics in which point-of-care testing and computational modeling are promising future directions for clinically relevant research. Further research in this area will enable identification of patients at high risk for arterial thrombosis, improve prevention and treatment based on shear-dependent biological mechanisms, and improve blood-contacting device design to reduce thrombosis risk.

  7. Modeling of shear wall buildings

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, A K [North Carolina State Univ., Raleigh (USA). Dept. of Civil Engineering

    1984-05-01

    Many nuclear power plant buildings, for example, the auxiliary building, have reinforced concrete shear walls as the primary lateral load resisting system. Typically, these walls have low height to length ratio, often less than unity. Such walls exhibit marked shear lag phenomenon which would affect their bending stiffness and the overall stress distribution in the building. The deformation and the stress distribution in walls have been studied which is applicable to both the short and the tall buildings. The behavior of the wall is divided into two parts: the symmetric flange action and the antisymmetry web action. The latter has two parts: the web shear and the web bending. Appropriate stiffness equations have been derived for all the three actions. These actions can be synthesized to solve any nonlinear cross-section. Two specific problems, that of lateral and torsional loadings of a rectangular box, have been studied. It is found that in short buildings shear lag plays a very important role. Any beam type formulation which either ignores shear lag or includes it in an idealized form is likely to lead to erroneous results. On the other hand a rigidity type approach with some modifications to the standard procedures would yield nearly accurate answers.

  8. Shear instability of a gyroid diblock copolymer

    DEFF Research Database (Denmark)

    Eskimergen, Rüya; Mortensen, Kell; Vigild, Martin Etchells

    2005-01-01

    -induced destabilization is discussed in relation to analogous observations on shear-induced order-to-order and disorder-to-order transitions observed in related block copolymer systems and in microemulsions. It is discussed whether these phenomena originate in shear-reduced fluctuations or shear-induced dislocations....

  9. Accurate shear measurement with faint sources

    International Nuclear Information System (INIS)

    Zhang, Jun; Foucaud, Sebastien; Luo, Wentao

    2015-01-01

    For cosmic shear to become an accurate cosmological probe, systematic errors in the shear measurement method must be unambiguously identified and corrected for. Previous work of this series has demonstrated that cosmic shears can be measured accurately in Fourier space in the presence of background noise and finite pixel size, without assumptions on the morphologies of galaxy and PSF. The remaining major source of error is source Poisson noise, due to the finiteness of source photon number. This problem is particularly important for faint galaxies in space-based weak lensing measurements, and for ground-based images of short exposure times. In this work, we propose a simple and rigorous way of removing the shear bias from the source Poisson noise. Our noise treatment can be generalized for images made of multiple exposures through MultiDrizzle. This is demonstrated with the SDSS and COSMOS/ACS data. With a large ensemble of mock galaxy images of unrestricted morphologies, we show that our shear measurement method can achieve sub-percent level accuracy even for images of signal-to-noise ratio less than 5 in general, making it the most promising technique for cosmic shear measurement in the ongoing and upcoming large scale galaxy surveys

  10. Shear and loading in channels: Oscillatory shearing and edge currents of superconducting vortices

    Science.gov (United States)

    Wambaugh, J. F.; Marchesoni, F.; Nori, Franco

    2003-04-01

    Via computer simulations we study the motion of quantized magnetic flux-lines, or vortices, confined to a straight pin-free channel in a strong-pinning superconducting sample. We find that, when a constant current is applied across this system, a very unusual oscillatory shearing appears, in which the vortices moving at the edges of the channel periodically trail behind and then suddenly leapfrog past the vortices moving in the inner rows. For small enough driving forces, this oscillatory shearing dynamic phase is replaced by a continuous shearing phase in which the distance between initially-nearby vortices grows in time, quickly destroying the order of the lattice. An animation of this novel “oscillatory leapfrogging shear” effect of the vortex edge currents appears in http://www-personal.engin.umich.edu/˜nori/channel/

  11. Vesicle dynamics in shear and capillary flows

    International Nuclear Information System (INIS)

    Noguchi, Hiroshi; Gompper, Gerhard

    2005-01-01

    The deformation of vesicles in flow is studied by a mesoscopic simulation technique, which combines multi-particle collision dynamics for the solvent with a dynamically triangulated surface model for the membrane. Shape transitions are investigated both in simple shear flows and in cylindrical capillary flows. We focus on reduced volumes, where the discocyte shape of fluid vesicles is stable, and the prolate shape is metastable. In simple shear flow at low membrane viscosity, the shear induces a transformation from discocyte to prolate with increasing shear rate, while at high membrane viscosity, the shear induces a transformation from prolate to discocyte, or tumbling motion accompanied by oscillations between these two morphologies. In capillary flow, at small flow velocities the symmetry axis of the discocyte is found not to be oriented perpendicular to the cylinder axis. With increasing flow velocity, a transition to a prolate shape occurs for fluid vesicles, while vesicles with shear-elastic membranes (like red blood cells) transform into a coaxial parachute-like shape

  12. O que pode significar a educação após Abu Ghraib: revisitando a política de educação de Adorno

    OpenAIRE

    Giroux, Henry A.

    2010-01-01

    How might education be used to question the common sense of the war on terrorism or to rouse citizens to challenge the social, political, and cultural conditions that led to the horrible events of Abu Ghraib? Just as crucially, we must ponder the limits of education. Is there a point where extreme conditions shortcircuit our moral instincts and ability to think and act rationally? If this is the case, what responsibility do we have to challenge the reckless violence-as-fi rst-resort ethos of ...

  13. An underwater shear compactor

    International Nuclear Information System (INIS)

    Biver, E.; Sims, J.

    1997-01-01

    This paper, originally presented at the WM'96 Conference in Tucson Arizona, describes a concept of a specialised decommissioning tool designed to operate underwater and to reduce the volume of radioactive components by shearing and compacting. The shear compactor was originally conceived to manage the size reduction of a variety of decommissioned stainless steel tubes stored within a reactor fuel cooling pond and which were consuming a substantial volume of the pond. The main objective of this tool was to cut the long tubes into shorter lengths and to compact them into a flat rectangular form which could be stacked on the pond floor, thus saving valuable space. The development programme, undertaken on this project, investigated a wide range of factors which could contribute to an extended cutting blade performance, ie: materials of construction, cutting blade shape and cutting loads required, shock effects, etc. The second phase was to review other aspects of the design, such as radiological protection, cutting blade replacement, maintenance, pond installation and resultant wall loads, water hydraulics, collection of products of shearing/compacting operations, corrosion of the equipment, control system, operational safety and the ability of the equipment to operate in dry environments. The paper summarises the extended work programme involved with this shear compactor tool. (author)

  14. Evolution of allowable stresses in shear for lumber

    Science.gov (United States)

    Robert L. Ethington; William L. Galligan; Henry M. Montrey; Alan D. Freas

    1979-01-01

    This paper surveys research leading to allowable shear stress parallel to grain for lumber. In early flexure tests of lumber, some pieces failed in shear. The estimated shear stress at time of failure was generally lower than shear strength measured on small, clear, straight-grained specimens. This and other engineering observations gave rise to adjustments that...

  15. Shear zones between rock units with no relative movement

    DEFF Research Database (Denmark)

    Koyi, Hemin; Schmeling, Harro; Burchardt, Steffi

    2013-01-01

    Shear zones are normally viewed as relatively narrow deformation zones that accommodate relative displacement between two "blocks" that have moved past each other in opposite directions. This study reports localized zones of shear between adjacent blocks that have not moved past each other. Such ...... given credit for and may be responsible for some reverse kinematics reported in shear zones....... or wakes, elongated bodies (vertical plates or horizontal rod-like bodies) produce tabular shear zones or wakes. Unlike conventional shear zones across which shear indicators usually display consistent symmetries, shear indicators on either side of the shear zone or wake reported here show reverse...... kinematics. Thus profiles exhibit shear zones with opposed senses of movement across their center-lines or -planes.We have used field observations and results from analytical and numerical models to suggest that examples of wakes are the transit paths that develop where denser blocks sink within salt...

  16. Effect of shear span-to-depth ratio on the shear behavior of BFRP-RC deep beams

    Directory of Open Access Journals (Sweden)

    Alhamad Siyam

    2017-01-01

    Full Text Available This study investigates the shear behavior of deep concrete beams reinforced with basalt fiber reinforced polymer (BFRP bars for flexure without web reinforcements. The experimental testing performed herein consisted of a total of 4 short beams, three of which were reinforced with BFRP and one beam was reinforced with steel bars. The primary test variable was the shear-span-to-effective-depth ratio (a/d and its influence on the beams’ mid-span deflections, shear capacity, load-deformation relationships and the failure modes.

  17. Evaluation of composite shear walls behavior (parametric study

    Directory of Open Access Journals (Sweden)

    Ali Nikkhoo

    2017-11-01

    Full Text Available Composite shear walls which are made of a layer of steel plate with a concrete cover in one or both sides of the steel plate, are counted as the third generation of the shear walls. Nowadays, composite shear walls are widely utilized in building new resisting structures as well as rehabilitating of the existing structures in earthquake-prone countries. Despite of its advantages, use of the composite shear walls is not yet prevalent as it demands more detailed appropriate investigation. Serving higher strength, flexibility and better energy absorption, while being more economical are the main advantages of this system which has paved its path to be used in high-rise buildings, structural retrofit and reservoir tanks. In this research, channel shear connectors are utilized to connect the concrete cover to the steel plate. As a key parameter, variation in the distance of shear connectors and their arrangement on the behavior of composite shear walls has been scrutinized. In addition, the shear stiffness, flexibility, out of plane displacement and the energy absorption of the structural system has been explored. For this purpose, several structural models with different shear distances and arrangements have been investigated. The obtained results reveal that with increase in shear connectors’ distance, the wall stiffness would reduce while its lateral displacement increases up to eighty percent While the out of plane displacement of the steel plate will reduce up to three times.

  18. PEMANFAATAN ZEOLIT DARI ABU SEKAM PADI DENGAN AKTIVASI ASAM UNTUK PENURUNAN KESADAHAN AIR

    Directory of Open Access Journals (Sweden)

    VH Putranto

    2016-04-01

    Full Text Available Aktivasi menggunakan asam kuat dalam sintesis zeolit dikenal dapat meningkatkan kemampuan zeolit sebagai adsorben. Penelitian ini bertujuan untuk memanfaatkan abu sekam padi sebagai sumber silika yang diaktivasi dengan HCl 2 M pada sintesis zeolit secara hidrotermal dan memanfaatkan zeolit hasil sintesis untuk menurunkan tingkat kesadahan air sumur. Proses aktivasi dilakukan dengan menggunakan larutan HCl 2 M. Zeolit hasil sintesis diuji secara kualitatif menggunakan Spektrofotometer Inframerah (FTIR dan Difraksi Sinar-X (XRD kemudian dimanfaatkan untuk menurunkan kadar ion logam Ca2+ dan Mg2+ penyebab kesadahan air dengan variasi waktu kontak (0, 20, 30, 40, 50, 60, 90, dan 120 menit dilanjutkan variasi massa zeolit sintetis (0,05; 0,1; 0,125; 0,25; serta 0,5 gram per volume air sumur 25 ml. Hasil uji komposisi kimia dengan Fluoresensi Sinar-X menunjukkan abu sekam padi yang telah diaktivasi memiliki kadar silika (SiO2 yang lebih tinggi yakni mencapai 95,83%. Hasil penelitian menunjukkan bahwa zeolit sintetis yang dihasilkan merupakan zeolit tipe NaY (zeolite like dengan kristal cancrinite sebagai fasa dominan. Adsorbsi optimum ion logam Ca2+ dan Mg2+ dalam air sumur oleh zeolit hasil sintesis terjadi pada waktu 60 menit dengan penyerapan optimum sebesar 94,71% Ca2+ dan 84,55% Mg2+ serta pada massa adsorben optimum 0,125 gram dengan penyerapan optimum sebesar 93,02% Ca2+ dan 83,78% Mg2+.Activation using a strong acid in zeolite synthesis is known can enhance the ability of zeolite as adsorbent. This study aims to utilize rice husk ash as a source of silica, which is activated with 2 M HCl in zeolite synthesis hydrothermally and apply the zeolite to reduce the level of hardness in well water. The activation process is performed by using HCl 2 M solution. Zeolite product is analyzed qualitatively using infrared spectrometer (FTIR and X-ray Diffraction (XRD and then used to reduce the levels of metal ions Ca2+ and Mg2+ which cause water hardness

  19. Acoustic waves in unbounded shear flows

    International Nuclear Information System (INIS)

    Chagelishvili, G.D.; Khujadze, G.R.; Lominadze, J.G.; Rogava, A.D.

    1996-05-01

    The linear evolution of acoustic waves in fluid flow with constant density and uniform shear of velocity is investigated. The process of the mean flow energy extraction by the three-dimensional acoustic waves which is due to the non-normality of linear dynamics in shear flows is analyzed. The thorough examination of the dynamics of different physical quantities, specifying the wave evolution, is outlined. The revealing of the behaviour becomes possible owing to the nonmodal approach that has been extensively used in the study of the perturbations evolution in shear flows since the beginning of the nineties. In addition, a detailed analyses of the physics of shear energy gain by vortex and acoustic perturbations is presented. (author). 28 refs, 7 figs

  20. Torsional shear flow of granular materials: shear localization and minimum energy principle

    Science.gov (United States)

    Artoni, Riccardo; Richard, Patrick

    2018-01-01

    The rheological properties of granular matter submitted to torsional shear are investigated numerically by means of discrete element method. The shear cell is made of a cylinder filled by grains which are sheared by a bumpy bottom and submitted to a vertical pressure which is applied at the top. Regimes differing by their strain localization features are observed. They originate from the competition between dissipation at the sidewalls and dissipation in the bulk of the system. The effects of the (i) the applied pressure, (ii) sidewall friction, and (iii) angular velocity are investigated. A model, based on the purely local μ (I)-rheology and a minimum energy principle is able to capture the effect of the two former quantities but unable to account the effect of the latter. Although, an ad hoc modification of the model allows to reproduce all the numerical results, our results point out the need for an alternative rheology.

  1. Failure modes of low-rise shear walls

    International Nuclear Information System (INIS)

    Farrar, C.R.; Reed, J.W.; Salmon, M.W.

    1993-01-01

    A summary of available data concerning the structural response of low-rise shear walls is presented. These data will be used to address two failure modes associated with shear wall structures. First, the data concerning the seismic capacity of the shear walls are examined, with emphasis on excessive deformations that can cause equipment failure. Second, the data concerning the dynamic properties of shear walls (stiffness and damping) that are necessary for computing the seismic inputs to attached equipment are summarized. This case addresses the failure of equipment when the structure remains functional

  2. Determination of wall shear stress from mean velocity and Reynolds shear stress profiles

    Science.gov (United States)

    Volino, Ralph J.; Schultz, Michael P.

    2018-03-01

    An analytical method is presented for determining the Reynolds shear stress profile in steady, two-dimensional wall-bounded flows using the mean streamwise velocity. The method is then utilized with experimental data to determine the local wall shear stress. The procedure is applicable to flows on smooth and rough surfaces with arbitrary pressure gradients. It is based on the streamwise component of the boundary layer momentum equation, which is transformed into inner coordinates. The method requires velocity profiles from at least two streamwise locations, but the formulation of the momentum equation reduces the dependence on streamwise gradients. The method is verified through application to laminar flow solutions and turbulent DNS results from both zero and nonzero pressure gradient boundary layers. With strong favorable pressure gradients, the method is shown to be accurate for finding the wall shear stress in cases where the Clauser fit technique loses accuracy. The method is then applied to experimental data from the literature from zero pressure gradient studies on smooth and rough walls, and favorable and adverse pressure gradient cases on smooth walls. Data from very near the wall are not required for determination of the wall shear stress. Wall friction velocities obtained using the present method agree with those determined in the original studies, typically to within 2%.

  3. Adiabatic shear localization in ultrafine grained 6061 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bingfeng, E-mail: biw009@ucsd.edu [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Department of Mechanical and Aerospace Engineering, University of California, San Diego (United States); State Key Laboratory for Powder Metallurgy, Central South University, Changsha, Hunan (China); Key Lab of Nonferrous Materials, Ministry of Education, Central South University, Changsha 410083 (China); Ma, Rui; Zhou, Jindian [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Li, Zezhou; Zhao, Shiteng [Department of Mechanical and Aerospace Engineering, University of California, San Diego (United States); Huang, Xiaoxia [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2016-10-15

    Localized shear is an important mode of deformation; it leads to catastrophic failure with low ductility, and occurs frequently during high strain-rate deformation. The hat-shaped specimen has been successfully used to generate shear bands under controlled shock-loading tests. The microstructure in the forced shear band was characterized by optical microscopy, microhardness, and transmission electron microscopy. The true flow stress in the shear region can reach 800 MPa where the strain is about 2.2. The whole shear localization process lasts for about 100 μs. The shear band is a long and straight band distinguished from the matrix by boundaries. It can be seen that the grains in the boundary of the shear band are highly elongated along the shear direction and form the elongated cell structures (0.2 µm in width), and the core of the shear band consists of a number of recrystallized equiaxed grains with 0.2−0.3 µm in diameters, and the second phase particles distribute in the boundary of the ultrafine equiaxed new grains. The calculated temperature in the shear band can reach about 667 K. Finally, the formation of the shear band in the ultrafine grained 6061 aluminum alloy and its microstructural evolution are proposed.

  4. Evolution of thermal ion transport barriers in reversed shear/ optimised shear plasmas

    International Nuclear Information System (INIS)

    Voitsekhovitch, I.; Garbet, X.; Moreau, D.; Bush, C.E.; Budny, R.V.; Gohil, P.; Kinsey, J.E.; Talyor, T.S.; Litaudon, X.

    2001-01-01

    The effects of the magnetic and ExB rotation shears on the thermal ion transport in advanced tokamak scenarios are analyzed through the predictive modelling of the evolution of internal transport barriers. Such a modelling is performed with an experimentally validated L-mode thermal diffusivity completed with a semi-empirical shear correction which is based on simple theoretical arguments from turbulence studies. A multi-machine test of the model on relevant discharges from the ITER Data Base (TFTR, DIII-D and JET) is presented. (author)

  5. Resolution of axial shear strain elastography

    International Nuclear Information System (INIS)

    Thitaikumar, Arun; Righetti, Raffaella; Krouskop, Thomas A; Ophir, Jonathan

    2006-01-01

    The technique of mapping the local axial component of the shear strain due to quasi-static axial compression is defined as axial shear strain elastography. In this paper, the spatial resolution of axial shear strain elastography is investigated through simulations, using an elastically stiff cylindrical lesion embedded in a homogeneously softer background. Resolution was defined as the smallest size of the inclusion for which the strain value at the inclusion/background interface was greater than the average of the axial shear strain values at the interface and inside the inclusion. The resolution was measured from the axial shear strain profile oriented at 45 0 to the axis of beam propagation, due to the absence of axial shear strain along the normal directions. The effects of the ultrasound system parameters such as bandwidth, beamwidth and transducer element pitch along with signal processing parameters such as correlation window length (W) and axial shift (ΔW) on the estimated resolution were investigated. The results show that the resolution (at 45 0 orientation) is determined by the bandwidth and the beamwidth. However, the upper bound on the resolution is limited by the larger of the beamwidth and the window length, which is scaled inversely to the bandwidth. The results also show that the resolution is proportional to the pitch and not significantly affected by the axial window shift

  6. EFEK PENGGUNAAN ABU GOSOK DAN SERBUK BATA MERAH PADA PEMBUATAN TELUR ASIN TERHADAP KANDUNGAN MIKROBA DALAM TELUR (THE EFFECT OF USING THE ASH AND THE RED BRICK POWDER IN MAKING OF THE SALTED EGGS TO THE MICROBIAL CONTENT OF THE EGGS

    Directory of Open Access Journals (Sweden)

    Heru Yuniati

    2013-07-01

    Full Text Available ABSTRACT Background: Salting is a way of preserving eggs with the dough / salt solution to boiling and boil for some time. As mixing the dough salt to soak the eggs, rub ash is commonly used in comparison with red brick powder. Purpose: determine the ability of red brick powder media in inhibiting bacteria than rub ash. Material and Method: Ten salted egg is made using a mixture of ash, salt and water in the ratio 4:2:2 ml, While ten more salted egg is made using a mixture of red brick powder, salt, and water in the ratio 4:2:2. Once the dough is well blended, each egg wrapped in dough evenly with a thickness of ± 2 mm. Then the eggs are stored in a plastic bucket in the open space. Microbial testing performed on total bacteria, and yeasts, as well as testing done to contain coliform, E. coli and Salmonella / Shigella on days 0, 5, 10, 15, and 20. Results: The total bacteria and yeasts in the two salted egg products decreased during salting, except on days -20, where an increase in total bacteria on salted egg with rub ash medium, but not on salted eggs with red brick powder medium. At the end of salting, the total number of bacteria of salted eggs for 4 x 102 and 0.9 x 102 colonies / gram, and total yeast and 0.45 x 102 8.7 x 102 colonies / gram. Conclusion: Salted eggs are made ​​using rub ash and red brick powder did not contain coliform bacteria, E. coli and Salmonella / Shigella, while the total number of bacteria and yeasts in the egg there is a difference. Keywords: Egg sauce, rub ash, red brick dust, microbes     ABSTRAK Latar Belakang: Pengasinan adalah cara mengawetkan telur dengan adonan garam dan merebusnya sampai mendidih selama beberapa waktu. Sebagai pencampur dalam adonan garam digunakan abu gosok dibandingkan dengan serbuk bata merah. Tujuan: mengetahui kemampuan media serbuk bata merah dalam menghambat bakteri dibandingkan dengan abu gosok. Bahan dan Cara: Sepuluh butir telur asin dibuat menggunakan campuran abu gosok

  7. Interfacial shear behavior of composite flanged concrete beams

    Directory of Open Access Journals (Sweden)

    Moataz Awry Mahmoud

    2014-08-01

    Full Text Available Composite concrete decks are commonly used in the construction of highway bridges due to their rapid constructability. The interfacial shear transfer between the top slab and the supporting beams is of great significance to the overall deck load carrying capacity and performance. Interfacial shear capacity is directly influenced by the distribution and the percentage of shear connectors. Research and design guidelines suggest the use of two different approaches to quantify the required interfacial shear strength, namely based on the maximum compressive forces in the flange at mid span or the maximum shear flow at the supports. This paper investigates the performance of flanged reinforced concrete composite beams with different shear connector’s distribution and reinforcing ratios. The study incorporated both experimental and analytical programs for beams. Key experimental findings suggest that concentrating the connectors at the vicinity of the supports enhances the ductility of the beam. The paper proposes a simple and straight forward approach to estimate the interfacial shear capacity that was proven to give good correlation with the experimental results and selected code provisions. The paper presents a method to predict the horizontal shear force between precast beams and cast in-situ slabs.

  8. Shear wave elastography with a new reliability indicator

    Directory of Open Access Journals (Sweden)

    Christoph F. Dietrich

    2016-09-01

    Full Text Available Non-invasive methods for liver stiffness assessment have been introduced over recent years. Of these, two main methods for estimating liver fibrosis using ultrasound elastography have become established in clinical practice: shear wave elastography and quasi-static or strain elastography. Shear waves are waves with a motion perpendicular (lateral to the direction of the generating force. Shear waves travel relatively slowly (between 1 and 10 m/s. The stiffness of the liver tissue can be assessed based on shear wave velocity (the stiffness increases with the speed. The European Federation of Societies for Ultrasound in Medicine and Biology has published Guidelines and Recommendations that describe these technologies and provide recommendations for their clinical use. Most of the data available to date has been published using the Fibroscan (Echosens, France, point shear wave speed measurement using an acoustic radiation force impulse (Siemens, Germany and 2D shear wave elastography using the Aixplorer (SuperSonic Imagine, France. More recently, also other manufacturers have introduced shear wave elastography technology into the market. A comparison of data obtained using different techniques for shear wave propagation and velocity measurement is of key interest for future studies, recommendations and guidelines. Here, we present a recently introduced shear wave elastography technology from Hitachi and discuss its reproducibility and comparability to the already established technologies.

  9. Shear wave elastography with a new reliability indicator.

    Science.gov (United States)

    Dietrich, Christoph F; Dong, Yi

    2016-09-01

    Non-invasive methods for liver stiffness assessment have been introduced over recent years. Of these, two main methods for estimating liver fibrosis using ultrasound elastography have become established in clinical practice: shear wave elastography and quasi-static or strain elastography. Shear waves are waves with a motion perpendicular (lateral) to the direction of the generating force. Shear waves travel relatively slowly (between 1 and 10 m/s). The stiffness of the liver tissue can be assessed based on shear wave velocity (the stiffness increases with the speed). The European Federation of Societies for Ultrasound in Medicine and Biology has published Guidelines and Recommendations that describe these technologies and provide recommendations for their clinical use. Most of the data available to date has been published using the Fibroscan (Echosens, France), point shear wave speed measurement using an acoustic radiation force impulse (Siemens, Germany) and 2D shear wave elastography using the Aixplorer (SuperSonic Imagine, France). More recently, also other manufacturers have introduced shear wave elastography technology into the market. A comparison of data obtained using different techniques for shear wave propagation and velocity measurement is of key interest for future studies, recommendations and guidelines. Here, we present a recently introduced shear wave elastography technology from Hitachi and discuss its reproducibility and comparability to the already established technologies.

  10. Hydrodynamical fluctuations in smooth shear flows

    International Nuclear Information System (INIS)

    Chagelishvili, G.D.; Khujadze, G.R.; Lominadze, J.G.

    1999-11-01

    Background of hydrodynamical fluctuations in a intrinsically/stochastically forced, laminar, uniform shear flow is studied. The employment of so-called nonmodal mathematical analysis makes it possible to represent the background of fluctuations in a new light and to get more insight into the physics of its formation. The basic physical processes responsible for the formation of vortex and acoustic wave fluctuation backgrounds are analyzed. Interplay of the processes at low and moderate shear rates is described. Three-dimensional vortex fluctuations around a given macroscopic state are numerically calculated. The correlation functions of the fluctuations of physical quantities are analyzed. It is shown that there exists subspace D k in the wave-number space (k-space) that is limited externally by spherical surface with radius k ν ≡ A/ν (where A is the velocity shear parameter, ν - the kinematic viscosity) in the nonequilibrium open system under study. The spatial Fourier harmonics of vortex as well as acoustic wave fluctuations are strongly subjected by flow shear (by the open character of the system) at wave-numbers satisfying the condition k ν . Specifically it is shown that in D k : The fluctuations are non-Markovian; the spatial spectral density of energy of the vortex fluctuations by far exceeds the white-noise; the term of a new type associated to the hydrodynamical fluctuation of velocity appears in the correlation function of pressure; the fluctuation background of the acoustic waves is completely different at low and moderate shear rates (at low shear rates it is reduced in D k in comparison to the uniform (non-shear) flow; at moderate shear rates it it comparable to the background of the vortex fluctuations). The fluctuation background of both the vortex and the acoustic wave modes is anisotropic. The possible significance of the fluctuation background of vortices for the subcritical transition to turbulence and Brownian motion of small macroscopic

  11. Simulation of shear thickening in attractive colloidal suspensions.

    Science.gov (United States)

    Pednekar, Sidhant; Chun, Jaehun; Morris, Jeffrey F

    2017-03-01

    The influence of attractive forces between particles under conditions of large particle volume fraction, ϕ, is addressed using numerical simulations which account for hydrodynamic, Brownian, conservative and frictional contact forces. The focus is on conditions for which a significant increase in the apparent viscosity at small shear rates, and possibly the development of a yield stress, is observed. The high shear rate behavior for Brownian suspensions has been shown in recent work [R. Mari, R. Seto, J. F. Morris and M. M. Denn PNAS, 2015, 112, 15326-15330] to be captured by the inclusion of pairwise forces of two forms, one a contact frictional interaction and the second a repulsive force often found in stabilized colloidal dispersions. Under such conditions, shear thickening is observed when shear stress is comparable to the sum of the Brownian stress, kT/a 3 , and a characteristic stress based on the combination of interparticle force, i.e. σ ∼ F 0 /a 2 with kT the thermal energy, F 0 the repulsive force scale and a the particle radius. At sufficiently large ϕ, this shear thickening can be very abrupt. Here it is shown that when attractive interactions are present with the noted forces, the shear thickening is obscured, as the viscosity shear thins with increasing shear rate, eventually descending from an infinite value (yield stress conditions) to a plateau at large stress; this plateau is at the same level as the large-shear rate viscosity found in the shear thickened state without attractive forces. It is shown that this behavior is consistent with prior observations in shear thickening suspensions modified to be attractive through depletion flocculation [V. Gopalakrishnan and C. F. Zukoski J. Rheol., 2004, 48, 1321-1344]. The contributions of the contact, attractive, and hydrodynamics forces to the bulk stress are presented, as are the contact networks found at different attractive strengths.

  12. Shear zones between rock units with no relative movement

    DEFF Research Database (Denmark)

    Koyi, H.; Schmeling, H.; Burchardt, S.

    2012-01-01

    , elongated bodies (vertical plates or horizontal rod-like bodies) produce tabular shear zones. Unlike conventional shear zones across which shear indicators ideally display consistent symmetries, shear indicators on either sides of the shear zone reported here show reverse kinematics. Thus profiles exhibit...... by progressive extension and (perhaps) where slabs of subducted oceanic lithosphere delaminate from the continental crust and sink into the asthenosphere. We also argue that such shear zones may be more common than they have been given the credit for and may be responsible for some of the kinematic reversals...

  13. Two-dimensional Shear Wave Elastography on Conventional Ultrasound Scanners with Time Aligned Sequential Tracking (TAST) and Comb-push Ultrasound Shear Elastography (CUSE)

    Science.gov (United States)

    Song, Pengfei; Macdonald, Michael C.; Behler, Russell H.; Lanning, Justin D.; Wang, Michael H.; Urban, Matthew W.; Manduca, Armando; Zhao, Heng; Callstrom, Matthew R.; Alizad, Azra; Greenleaf, James F.; Chen, Shigao

    2014-01-01

    Two-dimensional (2D) shear wave elastography presents 2D quantitative shear elasticity maps of tissue, which are clinically useful for both focal lesion detection and diffuse disease diagnosis. Realization of 2D shear wave elastography on conventional ultrasound scanners, however, is challenging due to the low tracking pulse-repetition-frequency (PRF) of these systems. While some clinical and research platforms support software beamforming and plane wave imaging with high PRF, the majority of current clinical ultrasound systems do not have the software beamforming capability, which presents a critical challenge for translating the 2D shear wave elastography technique from laboratory to clinical scanners. To address this challenge, this paper presents a Time Aligned Sequential Tracking (TAST) method for shear wave tracking on conventional ultrasound scanners. TAST takes advantage of the parallel beamforming capability of conventional systems and realizes high PRF shear wave tracking by sequentially firing tracking vectors and aligning shear wave data in the temporal direction. The Comb-push Ultrasound Shear Elastography (CUSE) technique was used to simultaneously produce multiple shear wave sources within the field-of-view (FOV) to enhance shear wave signal-to-noise-ratio (SNR) and facilitate robust reconstructions of 2D elasticity maps. TAST and CUSE were realized on a conventional ultrasound scanner (the General Electric LOGIQ E9). A phantom study showed that the shear wave speed measurements from the LOGIQ E9 were in good agreement to the values measured from other 2D shear wave imaging technologies. An inclusion phantom study showed that the LOGIQ E9 had comparable performance to the Aixplorer (Supersonic Imagine) in terms of bias and precision in measuring different sized inclusions. Finally, in vivo case analysis of a breast with a malignant mass, and a liver from a healthy subject demonstrated the feasibility of using the LOGIQ E9 for in vivo 2D shear wave

  14. Shear-induced phase changes in mixtures

    International Nuclear Information System (INIS)

    Romig, K.D.; Hanley, H.J.M.

    1986-01-01

    A thermodynamic theory to account for the behavior of liquid mixtures exposed to a shear is developed. One consequence of the theory is that shear-induced phase changes are predicted. The theory is based on a thermodynamics that includes specifically the shear rate in the formalism and is applied to mixtures by a straightforward modification of the corresponding states, conformalsolution approach. The approach is general but is used here for a mixture of Lennard-Jones particles with a Lennard-Jones equation of state as a reference fluid. The results are discussed in the context of the Scott and Van Konynenberg phase classification. It is shown that the influence of a shear does affect substantially the type of the phase behavior. Results from the model mixture are equated loosely with those from real polymeric liquids

  15. Contributions to a shallow aquifer study by reprocessed seismic sections from petroleum exploration surveys, eastern Abu Dhabi, United Arab Emirates

    Science.gov (United States)

    Woodward, D.

    1994-01-01

    The US Geological Survey, in cooperation with the National Drilling Company of Abu Dhabi, is conducting a 4-year study of the fresh and slightly saline groundwater resources of the eastern Abu Dhabi Emirate. Most of this water occurs in a shallow aquifer, generally less than 150 m deep, in the Al Ain area. A critical part of the Al Ain area coincides with a former petroleum concession area where about 2780 km of vibroseis data were collected along 94 seismic lines during 1981-1983. Field methods, acquistion parameters, and section processing were originally designed to enhance reflections expected at depths ranging from 5000 to 6000 m, and subsurface features directly associated with the shallow aquifer system were deleted from the original seismic sections. The original field tapes from the vibroseis survey were reprocessed in an attempt to extract shallow subsurface information (depths less than 550 m) for investigating the shallow aquifer. A unique sequence of reproccessing parameters was established after reviewing the results from many experimental tests. Many enhancements to the resolution of shallow seismic reflections resulted from: (1) application of a 20-Hz, low-cut filter; (2) recomputation of static corrections to a datum nearer the land surface; (3) intensive velocity analyses; and (4) near-trace muting analyses. The number, resolution, and lateral continuity of shallow reflections were greatly enhanced on the reprocessed sections, as was the delineation of shallow, major faults. Reflections on a synthetic seismogram, created from a borehole drilled to a depth of 786 m on seismic line IQS-11, matcheddprecisely with shallow reflections on the reprocessed section. The 33 reprocessed sections were instrumental in preparing a map showing the major structural features that affect the shallow aquifer system. Analysis of the map provides a better understanding of the effect of these shallow features on the regional occurrence, movement, and quality of

  16. Physics of Transitional Shear Flows Instability and Laminar–Turbulent Transition in Incompressible Near-Wall Shear Layers

    CERN Document Server

    Boiko, Andrey V; Grek, Genrih R; Kozlov, Victor V

    2012-01-01

    Starting from fundamentals of classical stability theory, an overview is given of the transition phenomena in subsonic, wall-bounded shear flows. At first, the consideration focuses on elementary small-amplitude velocity perturbations of laminar shear layers, i.e. instability waves, in the simplest canonical configurations of a plane channel flow and a flat-plate boundary layer. Then the linear stability problem is expanded to include the effects of pressure gradients, flow curvature, boundary-layer separation, wall compliance, etc. related to applications. Beyond the amplification of instability waves is the non-modal growth of local stationary and non-stationary shear flow perturbations which are discussed as well. The volume continues with the key aspect of the transition process, that is, receptivity of convectively unstable shear layers to external perturbations, summarizing main paths of the excitation of laminar flow disturbances. The remainder of the book addresses the instability phenomena found at l...

  17. Results of shear studies with 241-AY-101 sludge

    International Nuclear Information System (INIS)

    WARRANT, R.W.

    2001-01-01

    The Department of Energy's Tanks Focus Area (TFA) authorized a project to study the effect of shear on the settling properties of high-level waste sludge to support retrieval programs. A series of settling studies was conducted on a composite sample of tank 241-AY-101 (AY-101) material. Comparisons were made with duplicate samples that were sheared with a tissue homogenizer and allowed to settle. Aliquots of sheared and unsheared settled solids were submitted for chemical and radiological analyses. There are five major conclusions from the study that apply to AY-101 sludge: (1) Sludge settling rates are detectably decreased after shearing of particles by means of a tissue homogenizer. A significant decrease in the settling rates was measured after 2 minutes of shearing. A smaller additional decrease in the settling rates was observed after an additional 10 minutes of shearing. (2) Sodium and Cesium appear to be present in both the liquid and solid phases of the composite sample. (3) The shearing of the solids does not appear to significantly change the distribution of the radionuclides, ( 241 Am, 90 Sr, Total Alpha, or other radionuclides), within the solids. (4) The mean particle diameter decreases after shearing with the tissue homogenizer and affects the settling rate in proportion to the square of the particle diameter. (5) The sonication of the unsheared particles produces a similar particle size reduction to that of shearing with a tissue homogenizer. It is difficult to quantitatively compare the shear produced by a mixer pump installed in a double-shell tank with that produced by the tissue homogenizer in the laboratory. On a qualitative basis, the mixing pump would be expected to have less mechanical and more hydraulic shearing effect than the tissue homogenizer. Since the particle size distribution studies indicate that (for the AY-101 solids) the breaking up of particle aggregates is the main means of particle size reduction, then the hydraulic shearing

  18. Strain gradient drives shear banding in metallic glasses

    Science.gov (United States)

    Tian, Zhi-Li; Wang, Yun-Jiang; Chen, Yan; Dai, Lan-Hong

    2017-09-01

    Shear banding is a nucleation-controlled process in metallic glasses (MGs) involving multiple temporal-spatial scales, which hinders a concrete understanding of its structural origin down to the atomic scale. Here, inspired by the morphology of composite materials, we propose a different perspective of MGs as a hard particle-reinforced material based on atomic-scale structural heterogeneity. The local stable structures indicated by a high level of local fivefold symmetry (L5FS) act as hard "particles" which are embedded in the relatively soft matrix. We demonstrate this concept by performing atomistic simulations of shear banding in CuZr MG. A shear band is prone to form in a sample with a high degree of L5FS which is slowly quenched from the liquid. An atomic-scale analysis on strain and the structural evolution reveals that it is the strain gradient effect that has originated from structural heterogeneity that facilitates shear transformation zones (STZs) to mature shear bands. An artificial composite model with a high degree of strain gradient, generated by inserting hard MG strips into a soft MG matrix, demonstrates a great propensity for shear banding. It therefore confirms the critical role strain gradient plays in shear banding. The strain gradient effect on shear banding is further quantified with a continuum model and a mechanical instability analysis. These physical insights might highlight the strain gradient as the hidden driving force in transforming STZs into shear bands in MGs.

  19. Nonlinear interaction of Rayleigh--Taylor and shear instabilities

    International Nuclear Information System (INIS)

    Finn, J.M.

    1993-01-01

    Results on the nonlinear behavior of the Rayleigh--Taylor instability and consequent development of shear flow by the shear instability [Phys. Fluids B 4, 488 (1992)] are presented. It is found that the shear flow is generated at sufficient amplitude to reduce greatly the convective transport. For high viscosity, the time-asymptotic state consists of an equilibrium with shear flow and vortex flow (with islands, or ''cat's eyes''), or a relaxation oscillation involving an interplay between the shear instability and the Rayleigh--Taylor instability in the presence of shear. For low viscosity, the dominant feature is a high-frequency nonlinear standing wave consisting of convective vortices localized near the top and bottom boundaries. The localization of these vortices is due to the smaller shear near the boundary regions. The convective transport is largest around these convective vortices near the boundary and there is a region of good confinement near the center. The possible relevance of this behavior to the H mode and edge-localized modes (ELM's) in the tokamak edge region is discussed

  20. Edge Sheared Flows and Blob Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Myra, J.; D' Ippolito, D.; Russell, D., E-mail: jrmyra@lodestar.com [Lodestar Research Corporation, Boulder (United States); Davis, W. M.; Zweben, S. [Princeton Plasma Physics Laboratory, Princeton (United States); Terry, J.; LaBombard, B. [Massachusetts Institute of Technology, Cambridge (United States)

    2012-09-15

    Full text: A study of sheared flows in the edge and scrape-off layer (SOL) and their interaction with blob-filaments is presented. Edge sheared flows are believed to be important for the L-H, and H-L transitions. Blob generation and dynamics impacts both the (near-separatrix) scrape-off-layer (SOL) width critical for power handling in the divertor, and the interaction of plasma in the far SOL with plasma-facing components. These topics are critical for ITER and future devices. A fluid-based 2D curvature-interchange model embedded in the SOLT code is employed to study these issues. Sheared binormal flows both regulate the power flux crossing the separatrix and control the character of emitted turbulence structures such as blob-filaments. At a critical power level (depending on parameters) the laminar flows containing intermittent, but bound, structures give way to full-blown blob emissions signifying a transition from quasi-diffusive to convective transport. In order to diagnose sheared flows in experiments and assess their interaction with blobs, a blob-tracking algorithm has been developed and applied to both NSTX and Alcator C-Mod data. Blob motion and ellipticity can be affected by sheared flows, and are diagnosed and compared with seeded blob simulations. A picture of the interaction of blobs and sheared flows is emerging from advances in the theory and simulation of edge turbulence, combined with ever-improving capabilities for edge diagnostics and their analysis. (author)

  1. Evaluation of shear mounted elastomeric damper

    Science.gov (United States)

    Zorzi, E.; Walton, J.

    1982-01-01

    Viton-70 elastomeric shear mounted damper was built and tested on a T-55 power turbine spool in the rotor's high speed balancing rig. This application of a shear mounted elastomeric damper demonstrated for the first time, the feasibility of using elastomers as the primary rotor damping source in production turbine engine hardware. The shear damper design was selected because it was compatible with actual gas turbine engine radial space constraints, could accommodate both the radial and axial thrust loads present in gas turbine engines, and was capable of controlled axial preload. The shear damper was interchangeable with the production T-55 power turbine roller bearing support so that a direct comparison between the shear damper and the production support structure could be made. Test results show that the Viton-70 elastomer damper operated successfully and provided excellent control of both synchronous and nonsynchronous vibrations through all phases of testing up to the maximum rotor speed of 16,000 rpm. Excellent correlation between the predicted and experienced critical speeds, mode shapes and log decrements for the power turbine rotor and elastomer damper assembly was also achieved.

  2. Shear Melting of a Colloidal Glass

    Science.gov (United States)

    Eisenmann, Christoph; Kim, Chanjoong; Mattsson, Johan; Weitz, David A.

    2010-01-01

    We use confocal microscopy to explore shear melting of colloidal glasses, which occurs at strains of ˜0.08, coinciding with a strongly non-Gaussian step size distribution. For larger strains, the particle mean square displacement increases linearly with strain and the step size distribution becomes Gaussian. The effective diffusion coefficient varies approximately linearly with shear rate, consistent with a modified Stokes-Einstein relationship in which thermal energy is replaced by shear energy and the length scale is set by the size of cooperatively moving regions consisting of ˜3 particles.

  3. Shear induced structures in crystallizing cocoa butter

    Science.gov (United States)

    Mazzanti, Gianfranco; Guthrie, Sarah E.; Sirota, Eric B.; Marangoni, Alejandro G.; Idziak, Stefan H. J.

    2004-03-01

    Cocoa butter is the main structural component of chocolate and many cosmetics. It crystallizes in several polymorphs, called phases I to VI. We used Synchrotron X-ray diffraction to study the effect of shear on its crystallization. A previously unreported phase (phase X) was found and a crystallization path through phase IV under shear was observed. Samples were crystallized under shear from the melt in temperature controlled Couette cells, at final crystallization temperatures of 17.5^oC, 20^oC and 22.5^oC in Beamline X10A of NSLS. The formation of phase X was observed at low shear rates (90 s-1) and low crystallization temperature (17.5^oC), but was absent at high shear (720 s-1) and high temperature (20^oC). The d-spacing and melting point suggest that this new phase is a mixture rich on two of the three major components of cocoa butter. We also found that, contrary to previous reports, the transition from phase II to phase V can happen through the intermediate phase IV, at high shear rates and temperature.

  4. Experimental study on the adiabatic shear bands

    International Nuclear Information System (INIS)

    Affouard, J.

    1984-07-01

    Four martensitic steels (Z50CDV5 steel, 28CND8 steel, 35NCDV16 steel and 4340 steel) with different hardness between 190 and 600 Hsub(B) (Brinell hardness), have been studied by means of dynamic compressive tests on split Hopkinson pressure bar. Microscopic observations show that the fracture are associated to the development of adiabatic shear bands (except 4340 steel with 190 Hsub(B) hardness). By means of tests for which the deformation is stopped at predetermined levels, the measurement of shear and hardness inside the band and the matrix indicates the chronology of this phenomenon: first the localization of shear, followed by the formation of adiabatic shear band and ultimatly crack initiation and propagation. These results correlated with few simulations by finite elements have permitted to suggest two mecanisms of deformation leading to the formation of adiabatic shear bands in this specific test [fr

  5. Shear-induced inflation of coronal magnetic fields

    International Nuclear Information System (INIS)

    Klimchuk, J.A.

    1990-01-01

    Using numerical models of force-free magnetic fields, the shearing of footprints in arcade geometries leading to an inflation of the coronal magnetic field was examined. For each of the shear profiles considered, all of the field lines become elevated compared with the potential field. This includes cases where the shear is concentrated well away from the arcade axis, such that B(sub z), the component of field parallel to the axis, increases outward to produce an inward B(sub z) squared/8 pi magnetic pressure gradient force. These results contrast with an earlier claim, shown to be incorrect, that field lines can sometimes become depressed as a result of shear. It is conjectured that an inflation of the entire field will always result from the shearing of simple arcade configurations. These results have implications for prominence formation, the interplanetary magnetic flux, and possibly also coronal holes. 38 refs

  6. Practical Weak-lensing Shear Measurement with Metacalibration

    Energy Technology Data Exchange (ETDEWEB)

    Sheldon, Erin S. [Brookhaven National Laboratory, Bldg. 510, Upton, NY 11973 (United States); Huff, Eric M. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States)

    2017-05-20

    Metacalibration is a recently introduced method to accurately measure weak gravitational lensing shear using only the available imaging data, without need for prior information about galaxy properties or calibration from simulations. The method involves distorting the image with a small known shear, and calculating the response of a shear estimator to that applied shear. The method was shown to be accurate in moderate-sized simulations with galaxy images that had relatively high signal-to-noise ratios, and without significant selection effects. In this work we introduce a formalism to correct for both shear response and selection biases. We also observe that for images with relatively low signal-to-noise ratios, the correlated noise that arises during the metacalibration process results in significant bias, for which we develop a simple empirical correction. To test this formalism, we created large image simulations based on both parametric models and real galaxy images, including tests with realistic point-spread functions. We varied the point-spread function ellipticity at the five-percent level. In each simulation we applied a small few-percent shear to the galaxy images. We introduced additional challenges that arise in real data, such as detection thresholds, stellar contamination, and missing data. We applied cuts on the measured galaxy properties to induce significant selection effects. Using our formalism, we recovered the input shear with an accuracy better than a part in a thousand in all cases.

  7. Platelet-free shear flow assay facilitates analysis of shear-dependent functions of VWF and ADAMTS13.

    Science.gov (United States)

    Kraus, Emma; Kraus, Kristina; Obser, Tobias; Oyen, Florian; Klemm, Ulrike; Schneppenheim, Reinhard; Brehm, Maria A

    2014-12-01

    The multimeric form of von Willebrand factor (VWF), is the largest soluble protein in mammals and exhibits a multidomain structure resulting in multiple functions. Upon agonist stimulation endothelial cells secrete VWF multimers from Weibel-Palade bodies into the blood stream where VWF plays an essential role in platelet-dependent primary hemostasis. Elongation of VWF strings on the cells' surface leads to accessibility of VWF binding sites for proteins, such as platelet membrane glycoprotein Ib. The prothrombotic strings are size-regulated by the metalloprotease ADAMTS13 by shear force-activated proteolytic cleavage. VWF string formation was induced by histamine stimulation of HUVEC cells under unidirectional shear flow and VWF strings were detected employing the VWF binding peptide of platelet glycoprotein Ib coupled to latex beads. VWF strings were then used as substrate for kinetic studies of recombinant and plasma ADAMTS13. To investigate specific aspects of the shear-dependent functions of VWF and ADAMTS13, we developed a shear flow assay that allows observation of VWF string formation and their degradation by ADAMTS13 without the need for isolated platelets. Our assay specifically detects VWF strings, can be coupled with fluorescent applications and allows semi-automated, quantitative assessment of recombinant and plasma ADAMTS13 activity. Our assay may serve as a valuable research tool to investigate the biochemical characteristics of VWF and ADAMTS13 under shear flow and could complement diagnostics of von Willebrand Disease and Thrombotic Thrombocytopenic Purpura as it allows detection of shear flow-dependent dysfunction of VWD-associated VWF mutants as well as TTP-associated ADAMTS13 mutants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. An in silico framework to analyze the anisotropic shear wave mechanics in cardiac shear wave elastography

    Science.gov (United States)

    Caenen, Annette; Pernot, Mathieu; Peirlinck, Mathias; Mertens, Luc; Swillens, Abigail; Segers, Patrick

    2018-04-01

    Shear wave elastography (SWE) is a potential tool to non-invasively assess cardiac muscle stiffness. This study focused on the effect of the orthotropic material properties and mechanical loading on the performance of cardiac SWE, as it is known that these factors contribute to complex 3D anisotropic shear wave propagation. To investigate the specific impact of these complexities, we constructed a finite element model with an orthotropic material law subjected to different uniaxial stretches to simulate SWE in the stressed cardiac wall. Group and phase speed were analyzed in function of tissue thickness and virtual probe rotation angle. Tissue stretching increased the group and phase speed of the simulated shear wave, especially in the direction of the muscle fiber. As the model provided access to the true fiber orientation and material properties, we assessed the accuracy of two fiber orientation extraction methods based on SWE. We found a higher accuracy (but lower robustness) when extracting fiber orientations based on the location of maximal shear wave speed instead of the angle of the major axis of the ellipsoidal group speed surface. Both methods had a comparable performance for the center region of the cardiac wall, and performed less well towards the edges. Lastly, we also assessed the (theoretical) impact of pathology on shear wave physics and characterization in the model. It was found that SWE was able to detect changes in fiber orientation and material characteristics, potentially associated with cardiac pathologies such as myocardial fibrosis. Furthermore, the model showed clearly altered shear wave patterns for the fibrotic myocardium compared to the healthy myocardium, which forms an initial but promising outcome of this modeling study.

  9. Nongeometrically converted shear waves in marine streamer data

    NARCIS (Netherlands)

    Drijkoningen, G.G.; El Allouche, N.; Thorbecke, J.W.; Bada, G.

    2012-01-01

    Under certain circumstances, marine streamer data contain nongeometrical shear body wave arrivals that can be used for imaging. These shear waves are generated via an evanescent compressional wave in the water and convert to propagating shear waves at the water bottom. They are called

  10. Recent progress in shear punch testing

    International Nuclear Information System (INIS)

    Hamilton, M.L.; Toloczko, M.B.; Lucas, G.E.

    1994-09-01

    The shear punch test was developed in response to the needs of the materials development community for small-scale mechanical properties tests. Such tests will be of great importance when a fusion neutron simulation device is built, since such a device is expected to have a limited irradiation volume. The shear punch test blanks a circular disk from a fixed sheet metal specimen, specifically a TEM disk. Load-displacement data generated during the test can be related to uniaxial tensile properties such as yield and ultimate strength. Shear punch and tensile tests were performed at room temperature on a number of unirradiated aluminum, copper, vanadium, and stainless steel alloys and on several irradiated aluminum alloys. Recent results discussed here suggest that the relationship between shear punch strength and tensile strength varies with alloy class, although the relationship determined for the unirradiated condition remains valid for the irradiated aluminum alloys

  11. Stress analysis of shear/compression test

    International Nuclear Information System (INIS)

    Nishijima, S.; Okada, T.; Ueno, S.

    1997-01-01

    Stress analysis has been made on the glass fiber reinforced plastics (GFRP) subjected to the combined shear and compression stresses by means of finite element method. The two types of experimental set up were analyzed, that is parallel and series method where the specimen were compressed by tilted jigs which enable to apply the combined stresses, to the specimen. Modified Tsai-Hill criterion was employed to judge the failure under the combined stresses that is the shear strength under the compressive stress. The different failure envelopes were obtained between the two set ups. In the parallel system the shear strength once increased with compressive stress then decreased. On the contrary in the series system the shear strength decreased monotonicly with compressive stress. The difference is caused by the different stress distribution due to the different constraint conditions. The basic parameters which control the failure under the combined stresses will be discussed

  12. Shear-Induced Membrane Fusion in Viscous Solutions

    KAUST Repository

    Kogan, Maxim

    2014-05-06

    Large unilamellar lipid vesicles do not normally fuse under fluid shear stress. They might deform and open pores to relax the tension to which they are exposed, but membrane fusion occurring solely due to shear stress has not yet been reported. We present evidence that shear forces in a viscous solution can induce lipid bilayer fusion. The fusion of 1,2-dioleoyl-sn-glycero-3- phosphocholine (DOPC) liposomes is observed in Couette flow with shear rates above 3000 s-1 provided that the medium is viscous enough. Liposome samples, prepared at different viscosities using a 0-50 wt % range of sucrose concentration, were studied by dynamic light scattering, lipid fusion assays using Förster resonance energy transfer (FRET), and linear dichroism (LD) spectroscopy. Liposomes in solutions with 40 wt % (or more) sucrose showed lipid fusion under shear forces. These results support the hypothesis that under suitable conditions lipid membranes may fuse in response to mechanical-force- induced stress. © 2014 American Chemical Society.

  13. Edge-Induced Shear Banding in Entangled Polymeric Fluids.

    Science.gov (United States)

    Hemingway, Ewan J; Fielding, Suzanne M

    2018-03-30

    Despite decades of research, the question of whether solutions and melts of highly entangled polymers exhibit shear banding as their steady state response to a steadily imposed shear flow remains controversial. From a theoretical viewpoint, an important unanswered question is whether the underlying constitutive curve of shear stress σ as a function of shear rate γ[over ˙] (for states of homogeneous shear) is monotonic, or has a region of negative slope, dσ/dγ[over ˙]<0, which would trigger banding. Attempts to settle the question experimentally via velocimetry of the flow field inside the fluid are often confounded by an instability of the free surface where the sample meets the outside air, known as "edge fracture." Here we show by numerical simulation that in fact even only very modest edge disturbances-which are the precursor of full edge fracture but might well, in themselves, go unnoticed experimentally-can cause strong secondary flows in the form of shear bands that invade deep into the fluid bulk. Crucially, this is true even when the underlying constitutive curve is monotonically increasing, precluding true bulk shear banding in the absence of edge effects.

  14. Shear localization and microstructure in coarse grained beta titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bingfeng, E-mail: biw009@ucsd.edu [State Key Laboratory for Powder Metallurgy, Central South University, Changsha, Hunan (China); School of Materials Science and Engineering, Central South University, Changsha, Hunan (China); Department of Mechanical and Aerospace Engineering, University of California, San Diego, United States of America (United States); Key Lab of Nonferrous Materials, Ministry of Education, Central South University, Changsha, Hunan (China); Wang, Xiaoyan [State Key Laboratory for Powder Metallurgy, Central South University, Changsha, Hunan (China); School of Materials Science and Engineering, Central South University, Changsha, Hunan (China); Li, Zezhou [Department of Mechanical and Aerospace Engineering, University of California, San Diego, United States of America (United States); Ma, Rui [School of Materials Science and Engineering, Central South University, Changsha, Hunan (China); Zhao, Shiteng [Department of Mechanical and Aerospace Engineering, University of California, San Diego, United States of America (United States); Xie, Fangyu [State Key Laboratory for Powder Metallurgy, Central South University, Changsha, Hunan (China); School of Materials Science and Engineering, Central South University, Changsha, Hunan (China); Zhang, Xiaoyong [State Key Laboratory for Powder Metallurgy, Central South University, Changsha, Hunan (China)

    2016-01-15

    Adiabatic shear localization plays an important role in the deformation and failure of the coarse grained beta titanium alloy Ti-5 Al-5 Mo-5 V-1 Cr-1 Fe with grain size about 1 mm at high strain rate deformation. Hat shaped specimens with different nominal shear strains are used to induce the formation of shear bands under the controlled shock-loading experiments. The true stress in the specimens can reach about 1040 MPa where the strain is about 1.83. The whole shear localization process lasts about 35 μs. The microstructures within the shear band are investigated by optical microscopy, scanning electron microscopy / electron backscatter diffraction, and transmission electron microscopy. The results show that the width of the shear bands decreases with increasing nominal shear strain, and the grains in the transition region near the shear band are elongated along the shear band, and the core of the shear band consists of the ultrafine deformed grains with width of 0.1 μm and heavy dislocations. With the aims of accommodating the imposed shear strain and maintaining neighboring grain compatibility, the grain subdivision continues to take place within the band. A fiber texture is formed in the core of the shear band. The calculated temperature rise in the shear band can reach about 722 K. Dynamic recovery is responsible for the formation of the microstructure in coarse grained beta titanium alloy.

  15. Destruction of a Holothuria scabra population by overfishing at Abu Rhamada Island in the Red Sea.

    Science.gov (United States)

    Hasan, Mohamed Hamza

    2005-10-01

    Populations of Holothuria scabra at Abu Rhamada Island were investigated during 52 months, from July 1999 to October 2003. During the first 23 months (July, 1999-May, 2001) the Island had a robust population with a tri-modal size frequency distribution curve, very high densities (85.7-95.1 ind./100 m2 at the sandy habitat), high abundance (3362-3110 individuals) and biomass (46.7-34.3 kg/100 m2). Also, during this period most individuals were at depths between 4 and 6m and no individuals were recorded deeper than 15m. The population declined after harvesting began (June, 2001) and by March, 2002 the size frequency distribution showed a bimodal pattern with an obvious decrease in abundance of large individuals. There was also a slight reduction in densities (73.2-60.1 ind./100 m2 at the sandy habitat), abundance (2292-1682 individuals) and biomass (21.6-11.3 kg/100 m2), and a marked shift towards deeper waters. Overfishing reached its maximum during the final 19 months of the study, and by October, 2003, density (30.7-0.4 ind./100 m2 at the sandy habitat), abundance (802-10 individuals) and biomass (6.9-0.1 kg/100 m2) were all greatly reduced. The size frequency distribution of the population became unimodal, large animals disappeared and no recruits were seen. During this period, individuals were found at very deep depths (30 to >40 m). The study also showed that sandy substrate was the preferred habitat for H. scabra, accommodating the largest number of individuals. The population of H. scabra at Abu Rhamada Island was found to spawn biannually from 1999 to 2001, then only once during 2002 when high fishing pressure occurred, and ceased completely in 2003. The sex ratio was not significantly different from 1:1 before fishing begun, but shifted to an increasing male bias reaching 93% males by January 2003. None of the small animals remaining after January, 2003 could be sexed. Size at sexual maturity decreased from prefishing (185 mm for females and 160 mm for

  16. ATLAS virtual visit features Al-Quds University, a Palestinian university with campuses in Abu Dis and al-Bireh.

    CERN Multimedia

    claudia marcelloni

    2012-01-01

    Mon, 02 Apr - 14:00 CET (15:00 local) ATLAS virtual visit features Al-Quds University, a Palestinian university with campuses in Abu Dis and al-Bireh. As part of the "Physics Without Frontiers" project, funded by ICTP, Al-Quds is hosting a one day particle physics masterclass. During the day the students are given an introduction to particle physics, the LHC and the ATLAS Experiment, before having the chance to analyse real LHC data. This virtual visit comprises of a live tour around the ATLAS control room and the opportunity to ask questions to the ATLAS physicists. Al-Quds Physics has active research in accelerators, biophysics, laser, nuclear & particle, plasma, and solid state. A new collaboration is underway Forschungszentrum Jülich in spintronics, bioelectronics Alquds Physics is involved in the regional synchrotron SESAME in Jordan. Members include nine states from the region and over 10 observers worldwide. SESAME was established a long the same philosophy behind building CERN.

  17. Problems pilots face involving wind shear

    Science.gov (United States)

    Melvin, W. W.

    1977-01-01

    Educating pilots and the aviation industry about wind shears presents a major problem associated with this meteorological phenomenon. The pilot's second most pressing problem is the need for a language to discuss wind shear encounters with other pilots so that the reaction of the aircraft to the wind shear encounter can be accurately described. Another problem is the flight director which gives a centered pitch command for a given angular displacement from the glide slope. It was suggested that they should instead be called flight path command and should not center unless the aircraft is actually correcting to the flight path.

  18. Cosmology with cosmic shear observations: a review.

    Science.gov (United States)

    Kilbinger, Martin

    2015-07-01

    Cosmic shear is the distortion of images of distant galaxies due to weak gravitational lensing by the large-scale structure in the Universe. Such images are coherently deformed by the tidal field of matter inhomogeneities along the line of sight. By measuring galaxy shape correlations, we can study the properties and evolution of structure on large scales as well as the geometry of the Universe. Thus, cosmic shear has become a powerful probe into the nature of dark matter and the origin of the current accelerated expansion of the Universe. Over the last years, cosmic shear has evolved into a reliable and robust cosmological probe, providing measurements of the expansion history of the Universe and the growth of its structure. We review here the principles of weak gravitational lensing and show how cosmic shear is interpreted in a cosmological context. Then we give an overview of weak-lensing measurements, and present the main observational cosmic-shear results since it was discovered 15 years ago, as well as the implications for cosmology. We then conclude with an outlook on the various future surveys and missions, for which cosmic shear is one of the main science drivers, and discuss promising new weak cosmological lensing techniques for future observations.

  19. Kubo formulas for the shear and bulk viscosity relaxation times and the scalar field theory shear τπ calculation

    Science.gov (United States)

    Czajka, Alina; Jeon, Sangyong

    2017-06-01

    In this paper we provide a quantum field theoretical study on the shear and bulk relaxation times. First, we find Kubo formulas for the shear and the bulk relaxation times, respectively. They are found by examining response functions of the stress-energy tensor. We use general properties of correlation functions and the gravitational Ward identity to parametrize analytical structures of the Green functions describing both sound and diffusion mode. We find that the hydrodynamic limits of the real parts of the respective energy-momentum tensor correlation functions provide us with the method of computing both the shear and bulk viscosity relaxation times. Next, we calculate the shear viscosity relaxation time using the diagrammatic approach in the Keldysh basis for the massless λ ϕ4 theory. We derive a respective integral equation which enables us to compute η τπ and then we extract the shear relaxation time. The relaxation time is shown to be inversely related to the thermal width as it should be.

  20. The Mercier Criterion in Reversed Shear Tokamak Plasmas

    International Nuclear Information System (INIS)

    Kessel, C.; Chance, M.S.; Jardin, S.C.

    1999-01-01

    A recent numerical study has found that, contrary to conventional theoretical and experimental expectations, reversed shear plasmas are unstable primarily because the term proportional to the shear in the Mercier criterion is destabilizing. In the present study, the role of the magnetic shear, both local and global, is examined for various tokamak configurations with monotonic and non-monotonic safety factor profiles. The enhancement of the local shear due to the outward shift of the magnetic axis suggests that the latter are less susceptible to interchanges. Furthermore, by regrouping the terms in the criterion, the V'' term when differentiated instead with respect to the toroidal flux, is shown to absorb the dominant shear term. No Mercier instability is found for similar profiles as in the previous study

  1. Naesliden Project: direct shear tests of filled and unfilled joints

    Energy Technology Data Exchange (ETDEWEB)

    Ludvig, B.

    1980-05-15

    Joints from the Naesliden mine have been tested in a small field shear box and in a large shear rig. The large shear rig is described in detail, and its ability to test joints with an area of 600 mc/sup 2/ at a maximum normal stress of up to 20 MPa is emphasized. The stiffness and shear strength of the discontinuities in the Naesliden mine is presented. The values estimated at direct shear tests are compared with results from in situ measurements and tests on drillcores. The results show that the in situ measurements give lower values for the shear resistance than the direct shear tests. Estimation of the normal stiffness for joints in drill cores gave much higher stiffness than the estimations in the shear rig.

  2. Simulations of biopolymer networks under shear

    NARCIS (Netherlands)

    Huisman, Elisabeth Margaretha

    2011-01-01

    In this thesis we present a new method to simulate realistic three-dimensional networks of biopolymers under shear. These biopolymer networks are important for the structural functions of cells and tissues. We use the method to analyze these networks under shear, and consider the elastic modulus,

  3. Shear induced orientation of edible fat and chocolate crystals

    Science.gov (United States)

    Mazzanti, Gianfranco; Welch, Sarah E.; Marangoni, Alejandro G.; Sirota, Eric B.; Idziak, Stefan H. J.

    2003-03-01

    Shear-induced orientation of fat crystallites was observed during crystallization of cocoa butter, milk fat, stripped milk fat and palm oil. This universal effect was observed in systems crystallized under high shear. The minor polar components naturally present in milk fat were found to decrease the shear-induced orientation effect in this system. The competition between Brownian and shear forces, described by the Peclet number, determines the crystallite orientation. The critical radius size, from the Gibbs-Thomson equation, provides a tool to understand the effect of shear at the onset stages of crystallization.

  4. The microstructure and rheology of a model, thixotropic nanoparticle gel under steady shear and large amplitude oscillatory shear (LAOS)

    International Nuclear Information System (INIS)

    Min Kim, Jung; Kate Gurnon, A.; Wagner, Norman J.; Eberle, Aaron P. R.; Porcar, Lionel

    2014-01-01

    The microstructure-rheology relationship for a model, thermoreversible nanoparticle gel is investigated using a new technique of time-resolved neutron scattering under steady and time-resolved large amplitude oscillatory shear (LAOS) flows. A 21 vol. % gel is tested with varying strength of interparticle attraction. Shear-induced structural anisotropy is observed as butterfly scattering patterns and quantified through an alignment factor. Measurements in the plane of flow show significant, local anisotropy develops with alignment along the compressional axis of flow, providing new insights into how gels flow. The microstructure-rheology relationship is analyzed through a new type of structure-Lissajous plot that shows how the anisotropic microstructure is responsible for the observed LAOS response, which is beyond a response expected for a purely viscous gel with constant structure. The LAOS shear viscosities are observed to follow the “Delaware-Rutgers” rule. Rheological and microstructural data are successfully compared across a broad range of conditions by scaling the shear rate by the strength of attraction, providing a method to compare behavior between steady shear and LAOS experiments. However, important differences remain between the microstructures measured at comparatively high frequency in LAOS experiments and comparable steady shear experiments that illustrate the importance of measuring the microstructure to properly interpret the nonlinear, dynamic rheological response

  5. The microstructure and rheology of a model, thixotropic nanoparticle gel under steady shear and large amplitude oscillatory shear (LAOS)

    Energy Technology Data Exchange (ETDEWEB)

    Min Kim, Jung; Kate Gurnon, A.; Wagner, Norman J., E-mail: wagnernj@udel.edu [Department of Chemical and Biomolecular Engineering and Center for Neutron Science, University of Delaware, Newark, Delaware 19716 (United States); Eberle, Aaron P. R. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Porcar, Lionel [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 and Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9 (France)

    2014-09-01

    The microstructure-rheology relationship for a model, thermoreversible nanoparticle gel is investigated using a new technique of time-resolved neutron scattering under steady and time-resolved large amplitude oscillatory shear (LAOS) flows. A 21 vol. % gel is tested with varying strength of interparticle attraction. Shear-induced structural anisotropy is observed as butterfly scattering patterns and quantified through an alignment factor. Measurements in the plane of flow show significant, local anisotropy develops with alignment along the compressional axis of flow, providing new insights into how gels flow. The microstructure-rheology relationship is analyzed through a new type of structure-Lissajous plot that shows how the anisotropic microstructure is responsible for the observed LAOS response, which is beyond a response expected for a purely viscous gel with constant structure. The LAOS shear viscosities are observed to follow the “Delaware-Rutgers” rule. Rheological and microstructural data are successfully compared across a broad range of conditions by scaling the shear rate by the strength of attraction, providing a method to compare behavior between steady shear and LAOS experiments. However, important differences remain between the microstructures measured at comparatively high frequency in LAOS experiments and comparable steady shear experiments that illustrate the importance of measuring the microstructure to properly interpret the nonlinear, dynamic rheological response.

  6. Value of shear wave arrival time contour display in shear wave elastography for breast masses diagnosis.

    Science.gov (United States)

    Zhou, Bang-Guo; Wang, Dan; Ren, Wei-Wei; Li, Xiao-Long; He, Ya-Ping; Liu, Bo-Ji; Wang, Qiao; Chen, Shi-Gao; Alizad, Azra; Xu, Hui-Xiong

    2017-08-01

    To evaluate the diagnostic performance of shear wave arrival time contour (SWATC) display for the diagnosis of breast lesions and to identify factors associated with the quality of shear wave propagation (QSWP) in breast lesions. This study included 277 pathologically confirmed breast lesions. Conventional B-mode ultrasound characteristics and shear wave elastography parameters were computed. Using the SWATC display, the QSWP of each lesion was assigned to a two-point scale: score 1 (low quality) and score 2 (high quality). Binary logistic regression analysis was performed to identify factors associated with QSWP. The area under the receiver operating characteristic curve (AUROC) for QSWP to differentiate benign from malignant lesions was 0.913, with a sensitivity of 91.9%, a specificity of 90.7%, a positive predictive value (PPV) of 74.0%, and a negative predictive value (NPV) of 97.5%. Compared with using the standard deviation of shear wave speed (SWS SD ) alone, SWS SD combined with QSWP increased the sensitivity from 75.8% to 93.5%, but decreased the specificity from 95.8% to 89.3% (P breast lesions.

  7. Multifractal spectra in shear flows

    Science.gov (United States)

    Keefe, L. R.; Deane, Anil E.

    1989-01-01

    Numerical simulations of three-dimensional homogeneous shear flow and fully developed channel flow, are used to calculate the associated multifractal spectra of the energy dissipation field. Only weak parameterization of the results with the nondimensional shear is found, and this only if the flow has reached its asymptotic development state. Multifractal spectra of these flows coincide with those from experiments only at the range alpha less than 1.

  8. CFD simulation of estimating critical shear stress for cleaning flat ...

    Indian Academy of Sciences (India)

    Sumit Kawale

    2017-11-22

    Nov 22, 2017 ... Jet impingement; wall shear stress; cleaning of flat plate; turbulence model; critical shear stress; ... On comparing the theoretical predictions with wall shear ... distance and Reynolds number on peak value of local shear stress ...

  9. Development of Shear Connections in Steelconcrete Composite Structures

    Science.gov (United States)

    Biegus, Antoni; Lorenc, Wojciech

    2015-03-01

    Different types of shear connectors and modelling techniques are presented. Basic research conducted or presented after year 2000 is taken into consideration, following the idea of concrete dowel implemented in the form of perfobond strip at the beginning of the 1980s by F. Leonhardt. The latest research in the field of continuous shear connectors applied in bridges is highlited with special focus at the composite dowel shear connection, as it seems to be the most modern solution being strongly introduced to the industry. Final shape of composite dowel shear connection is presented.

  10. Time-dependent behavior of rough discontinuities under shearing conditions

    Science.gov (United States)

    Wang, Zhen; Shen, Mingrong; Ding, Wenqi; Jang, Boan; Zhang, Qingzhao

    2018-02-01

    The mechanical properties of rocks are generally controlled by their discontinuities. In this study, the time-dependent behavior of rough artificial joints under shearing conditions was investigated. Based on Barton’s standard profile lines, samples with artificial joint surfaces were prepared and used to conduct the shear and creep tests. The test results showed that the shear strength of discontinuity was linearly related to roughness, and subsequently an empirical equation was established. The long-term strength of discontinuity can be identified using the inflection point of the isocreep-rate curve, and it was linearly related to roughness. Furthermore, the ratio of long-term and instantaneous strength decreased with the increase of roughness. The shear-stiffness coefficient increased with the increase of shear rate, and the influence of shear rate on the shear stiffness coefficient decreased with the decrease of roughness. Further study of the mechanism revealed that these results could be attributed to the different time-dependent behavior of intact and joint rocks.

  11. Small-scale wind shear definition for aerospace vehicle design.

    Science.gov (United States)

    Fichtl, G. H.

    1972-01-01

    Rawinsonde wind profile data provide adequate wind shear information for vertical height intervals greater than 1 km. To specify wind shears for intervals below 1 km for space vehicle design, detailed wind-profile information like that provided by the FPS-16 Radar/Jimsphere system or an extrapolation procedure is required. This paper is concerned with the latter alternative. It is assumed that any realization from an ensemble of wind profiles can be represented in terms of a Fourier integral. This permits the calculation of the ensemble standard deviation and mean of the corresponding shear ensemble for any altitude and shear interval in terms of the power spectrum of the ensemble of wind profiles. The results of these calculations show that the mean and standard deviation of the wind shear ensemble, as well as the wind shear for any percentile, asymptotically behave like the vertical interval to the 0.7 power. This result is in excellent agreement with shear data from Cape Kennedy, Fla.

  12. Fluid Effects on Shear Waves in Finely Layered Porous Media

    International Nuclear Information System (INIS)

    Berryman, J G

    2004-01-01

    Although there are five effective shear moduli for any layered VTI medium, one and only one effective shear modulus for the layered system contains all the dependence of pore fluids on the elastic or poroelastic constants that can be observed in vertically polarized shear waves. Pore fluids can increase the magnitude the shear energy stored by this modulus by a term that ranges from the smallest to the largest shear moduli of the VTI system. But, since there are five shear moduli in play, the increase in shear energy overall is reduced by a factor of about 5 in general. We can therefore give definite bounds on the maximum increase of shear modulus, being about 20% of the permitted range, when gas is fully replaced by liquid. An attendant increase of density (depending on porosity and fluid density) by approximately 5 to 10% partially offsets the effect of this shear modulus increase. Thus, an increase of shear wave speed on the order of 5 to 10% is shown to be possible when circumstances are favorable - i.e., when the shear modulus fluctuations are large (resulting in strong anisotropy), and the medium behaves in an undrained fashion due to fluid trapping. At frequencies higher than seismic (such as sonic and ultrasonic waves for well-logging or laboratory experiments), short response times also produce the requisite undrained behavior and, therefore, fluids also affect shear waves at high frequencies by increasing rigidity

  13. Localization in inelastic rate dependent shearing deformations

    KAUST Repository

    Katsaounis, Theodoros

    2016-09-18

    Metals deformed at high strain rates can exhibit failure through formation of shear bands, a phenomenon often attributed to Hadamard instability and localization of the strain into an emerging coherent structure. We verify formation of shear bands for a nonlinear model exhibiting strain softening and strain rate sensitivity. The effects of strain softening and strain rate sensitivity are first assessed by linearized analysis, indicating that the combined effect leads to Turing instability. For the nonlinear model a class of self-similar solutions is constructed, that depicts a coherent localizing structure and the formation of a shear band. This solution is associated to a heteroclinic orbit of a dynamical system. The orbit is constructed numerically and yields explicit shear localizing solutions. © 2016 Elsevier Ltd

  14. Localization in inelastic rate dependent shearing deformations

    KAUST Repository

    Katsaounis, Theodoros; Lee, Min-Gi; Tzavaras, Athanasios

    2016-01-01

    Metals deformed at high strain rates can exhibit failure through formation of shear bands, a phenomenon often attributed to Hadamard instability and localization of the strain into an emerging coherent structure. We verify formation of shear bands for a nonlinear model exhibiting strain softening and strain rate sensitivity. The effects of strain softening and strain rate sensitivity are first assessed by linearized analysis, indicating that the combined effect leads to Turing instability. For the nonlinear model a class of self-similar solutions is constructed, that depicts a coherent localizing structure and the formation of a shear band. This solution is associated to a heteroclinic orbit of a dynamical system. The orbit is constructed numerically and yields explicit shear localizing solutions. © 2016 Elsevier Ltd

  15. On the self-organizing process of large scale shear flows

    Energy Technology Data Exchange (ETDEWEB)

    Newton, Andrew P. L. [Department of Applied Maths, University of Sheffield, Sheffield, Yorkshire S3 7RH (United Kingdom); Kim, Eun-jin [School of Mathematics and Statistics, University of Sheffield, Sheffield, Yorkshire S3 7RH (United Kingdom); Liu, Han-Li [High Altitude Observatory, National Centre for Atmospheric Research, P. O. BOX 3000, Boulder, Colorado 80303-3000 (United States)

    2013-09-15

    Self organization is invoked as a paradigm to explore the processes governing the evolution of shear flows. By examining the probability density function (PDF) of the local flow gradient (shear), we show that shear flows reach a quasi-equilibrium state as its growth of shear is balanced by shear relaxation. Specifically, the PDFs of the local shear are calculated numerically and analytically in reduced 1D and 0D models, where the PDFs are shown to converge to a bimodal distribution in the case of finite correlated temporal forcing. This bimodal PDF is then shown to be reproduced in nonlinear simulation of 2D hydrodynamic turbulence. Furthermore, the bimodal PDF is demonstrated to result from a self-organizing shear flow with linear profile. Similar bimodal structure and linear profile of the shear flow are observed in gulf stream, suggesting self-organization.

  16. Research Concerning the Shearing Strength of Black Locust Wood

    Directory of Open Access Journals (Sweden)

    Mihaela POROJAN

    2011-06-01

    Full Text Available The paper presents the experimental resultsobtained for the shearing strength of black locustwood (Robinia pseudacacia L. harvested from twogeographical areas (North and South of Romania.Wood is subjected to shearing stress when usedwithin different fields, and especially inconstructions. Tangential stresses are produced inthe shearing sections and they are influenced by thestructure of wood through the position of theshearing plane and of the force direction towards thegrain. Accordingly, several shearing types arepossible. The shearing strengths for the three mainshearing types, both on radial and tangentialdirection were determined within the present study.The evaluation of data was achieved by using theANOVA analysis, in order to test the level ofsignificance depending on the shearing planeorientation and the harvesting area. The obtainedresults were compared to the values mentionedwithin reference literature for this wood species andtwo other hardwood species with similar density. It isworth to be mentioned that the shearing strengths ofblack locust wood from Romania (both from Northand South are generally higher than those indicatedby reference literature for oak and beech. Thisrecommends black locust wood as constructionwood and for other applications where wood issubjected to shearing stress.

  17. Seismic cycle feedbacks in a mid-crustal shear zone

    Science.gov (United States)

    Melosh, Benjamin L.; Rowe, Christie D.; Gerbi, Christopher; Smit, Louis; Macey, Paul

    2018-07-01

    Mid-crustal fault rheology is controlled by alternating brittle and plastic deformation mechanisms, which cause feedback cycles that influence earthquake behavior. Detailed mapping and microstructural observations in the Pofadder Shear Zone (Namibia and South Africa) reveal a lithologically heterogeneous shear zone core with quartz-rich mylonites and ultramylonites, plastically overprinted pseudotachylyte and active shear folds. We present evidence for a positive feedback cycle in which coseismic grain size reduction facilitates active shear folding by enhancing competency contrasts and promoting crystal plastic flow. Shear folding strengthens a portion of a shear zone by limb rotation, focusing deformation and promoting plastic flow or brittle slip in resulting areas of localized high stress. Using quartz paleopiezometry, we estimate strain and slip rates consistent with other studies of exhumed shear zones and modern plate boundary faults, helping establish the Pofadder Shear Zone as an ancient analogue to modern, continental-scale, strike-slip faults. This feedback cycle influences seismicity patterns at the scale of study (10s of meters) and possibly larger scales as well, and contributes to bulk strengthening of the brittle-plastic transition on modern plate boundary faults.

  18. Abu Ghraib and Beyond: Torture as an Extension of the Desiring Machine

    Directory of Open Access Journals (Sweden)

    Hania Nashef

    2012-11-01

    Full Text Available In his discussion of Dante’s Inferno, Edward Said writes that “Maometto” or Mohammed occupies the eighth circle in the nine circles of Hell, belonging to “a rigid hierarchy of evils.”  According to Said, “Maometto” is “endlessly being cleft in two from his chin to his anus,” a punishment in Dante’s belief is well deserved because of Maometto’s sensuality and “pretensions to theological eminence.”  Such graphic description of torment evokes scenes of torture we have of late witnessed in Abu Ghreib and Guantanamo.  Prisoners, not only, were subjected to physical abuse but were also subjected to acts of sexual perversion as was revealed by the photos.  Furthermore, the latter showed those who partook in these actions seemed to be enjoying the power that the exercise of torture gave them.  Robert J.C. Young states that Colonialism “was not only a machine of war … but also a desiring machine.”  This poses the question as to whether torture does allow for the enactment of repressed desire by allowing it to surface by providing it with a venue in which it becomes acceptable.  Moreover, does Colonialism in its previous or in its current form, only sustain itself fundamentally through constant violence, of which perversion is a vital component as these practices are playing into the repertoire of the evil East, or is the perversion an extension of a suppressed Oedipus complex?

  19. Sheared flow layer formation in tokamak plasmas with reversed magnetic shear

    International Nuclear Information System (INIS)

    Dong, J.Q.; Long, Y.X.; Mou, Z.Z.; Zhang, J.H.; Li, J.Q.

    2005-01-01

    Sheared flow layer (SFL) formation due to magnetic energy release through tearing-reconnections in tokamak plasmas is investigated. The characteristics of the SFLs created in the development of double tearing mode, mediated by electron viscosity in configurations with non-monotonic safety factor q profiles and, therefore, two rational flux surfaces of same q value, are analyzed in detail as an example. Quasi-linear simulations demonstrate that the sheared flows induced by the mode have desirable characteristics (lying at the boundaries of the magnetic islands), and sufficient levels required for internal transport barrier (ITB) formation. A possible correlation of the SFLs with experimental observations, that double transport barrier structures are preferentially formed in proximity of the two rational surfaces, is also proffered. (author)

  20. Infant Feeding Practices of Emirati Women in the Rapidly Developing City of Abu Dhabi, United Arab Emirates

    Directory of Open Access Journals (Sweden)

    Hazel Gardner

    2015-09-01

    Full Text Available Rapid economic and cultural transition in the United Arab Emirates (UAE has been accompanied by new challenges to public health; most notably a rapid rise in chronic disease. Breastfeeding is known to improve health outcomes in adulthood, is associated with reduced risk of developing chronic disease, and is therefore an important public health issue for this rapidly increasing population. Factors associated with infant feeding practices were examined in a cohort of 125 Emirati women and their infants, with data collected at birth and 3, 6 and 15 months postpartum by questionnaires and interviews. Participants were recruited in the Corniche Hospital, the main maternity hospital in the city of Abu Dhabi. Factors affecting the duration of breastfeeding and the introduction of complementary foods were investigated using univariate and multivariate statistics. Recommended infant feeding practices, such as exclusive breastfeeding for the first six months of life and timely introduction of appropriate complementary foods, were poorly adhered to. Factors implicated in early cessation of breastfeeding included: time to first breastfeed, mother’s education level, employment status and early introduction of complementary foods.

  1. MUSLIM-CHRISTIAN DEBATES IN THEEARLY ‘ABBASID PERIOD: The Cases of Timothy I and Theodore Abu Qurra

    Directory of Open Access Journals (Sweden)

    Hans Abdiel Harmakaputra

    2014-12-01

    Full Text Available The era of the early ‘Abbasid caliphate made an important mark on the history of the world by the event of the Greek translation movement, i.e. the translation of Greek thoughts into the Arabic language. In addition to this development, the era also saw the flourishing of interreligious discourse, in both polemical literatures and religious debates, especially between Christians and Muslims. This article tries to describe how those two historical remarks are correlated under the light of other factors such as politics and religious identity. The earliest debate was happened between caliph al-Mahdi (r. 755-785 CE and a Nestorian Catholicos, Timothy I (728- 823 CE, as the first sample of religious discourses. The second one is the debate between the caliph al-Ma’mun (r. 813-833CE, who arranged many religious debates in his court, with Theodore Abu Qurra (755 – 830 CE, Bishop of Harran. By knowing the motives of the two caliphs who sponsored those events, readers would catch a better picture of the historical contexts of that time.

  2. Infant Feeding Practices of Emirati Women in the Rapidly Developing City of Abu Dhabi, United Arab Emirates.

    Science.gov (United States)

    Gardner, Hazel; Green, Katherine; Gardner, Andrew

    2015-09-02

    Rapid economic and cultural transition in the United Arab Emirates (UAE) has been accompanied by new challenges to public health; most notably a rapid rise in chronic disease. Breastfeeding is known to improve health outcomes in adulthood, is associated with reduced risk of developing chronic disease, and is therefore an important public health issue for this rapidly increasing population. Factors associated with infant feeding practices were examined in a cohort of 125 Emirati women and their infants, with data collected at birth and 3, 6 and 15 months postpartum by questionnaires and interviews. Participants were recruited in the Corniche Hospital, the main maternity hospital in the city of Abu Dhabi. Factors affecting the duration of breastfeeding and the introduction of complementary foods were investigated using univariate and multivariate statistics. Recommended infant feeding practices, such as exclusive breastfeeding for the first six months of life and timely introduction of appropriate complementary foods, were poorly adhered to. Factors implicated in early cessation of breastfeeding included: time to first breastfeed, mother's education level, employment status and early introduction of complementary foods.

  3. Shear stresses around circular cylindrical openings

    NARCIS (Netherlands)

    Hoogenboom, P.C.J.; Van Weelden, C.; Blom, C.M.B.

    2010-01-01

    In this paper stress concentrations are studied around circular cylindrical openings or voids in a linear elastic continuum. The loading is such that a uniform shear stress occurs in the continuum, which is disturbed by the opening. The shear stress is in the direction of the centre axis of the

  4. Intra-Continental Deformation by Mid-Crustal Shearing and Doming in a Cenozoic Compressive Setting Along the Ailao Shan-Red River Shear Zone

    Science.gov (United States)

    Zhang, B.

    2016-12-01

    Large-scale lateral strike-slip shear zones have been a key point in the debate about the deformation mechanisms of Asia in response to the India-Asia collision. The exhumed gneiss has been attributed to lateral strike-slip shear zone. This hypothesis has been challenged by recent discoveries indicating that a contractional doming deformation prior to the initiation of lateral strike-slip shearing. The Cenozoic Xuelong Shan antiformal dome is located at the northern segment of the Ailao Shan-Red River shear zone. Subhorizontal foliation in the gneiss core are recognized, representing a broad top-to-NE shear initiated under amphibolite facies conditions and propagated into greenschist facies in the mantling schist and strike-slip shear zone. Quartz CPOs and opening angles of crossed girdle fabrics in quartz suggest that the deformation temperatures increased with increasing structural depth from 300-500 °C in the mantling schist to ≥650 °C in the gneissic core. This trend is mirrored by variations in the metamorphic grade of the syn-kinematic mineral assemblages and microstructures, which ranges from garnet + amphibole + biotite + sillimanite + rutite + feldspar in the core to garnet + staurolite + biotite + epidote + muscovite within the limb units. Five-stage deformation is identified: (1) a broad top-to-NE shear in the subhorizontal level (D1); (2) opposing reverse-sense shear along the two schist limbs of the dome during contraction-related doming (D2-D3); (3) sinistral strike-slip shearing within the eastern limb (D4); and (4) extensional deformation (D5). The antiformal dome formation had been roughly coeval with top-to-NE ductile shearing in the mid-crust at 32 Ma or earlier. The geometries of the antiformal dome in the Xuelong Shan dome are similar to those associated with the antiform in the Dai Nui Con Voi, Diancang Shan and Ailao Shan zones. It is likely that the complex massifs, which define a regional linear gneiss dome zone in Cenozoic intra

  5. Swimming efficiency in a shear-thinning fluid

    Science.gov (United States)

    Nganguia, Herve; Pietrzyk, Kyle; Pak, On Shun

    2017-12-01

    Micro-organisms expend energy moving through complex media. While propulsion speed is an important property of locomotion, efficiency is another factor that may determine the swimming gait adopted by a micro-organism in order to locomote in an energetically favorable manner. The efficiency of swimming in a Newtonian fluid is well characterized for different biological and artificial swimmers. However, these swimmers often encounter biological fluids displaying shear-thinning viscosities. Little is known about how this nonlinear rheology influences the efficiency of locomotion. Does the shear-thinning rheology render swimming more efficient or less? How does the swimming efficiency depend on the propulsion mechanism of a swimmer and rheological properties of the surrounding shear-thinning fluid? In this work, we address these fundamental questions on the efficiency of locomotion in a shear-thinning fluid by considering the squirmer model as a general locomotion model to represent different types of swimmers. Our analysis reveals how the choice of surface velocity distribution on a squirmer may reduce or enhance the swimming efficiency. We determine optimal shear rates at which the swimming efficiency can be substantially enhanced compared with the Newtonian case. The nontrivial variations of swimming efficiency prompt questions on how micro-organisms may tune their swimming gaits to exploit the shear-thinning rheology. The findings also provide insights into how artificial swimmers should be designed to move through complex media efficiently.

  6. Forflytning: shear og friktion

    DEFF Research Database (Denmark)

    2005-01-01

    friktion). Formålet med filmprojektet er: At give personalet i Apopleksiafsnittet viden om shear og friktion, så det motiveres til forebyggelse. Mål At udarbejde et enkelt undervisningsmateriale til bed-side-brug Projektbeskrivelse (resume) Patienter med apopleksi er særligt udsatte for tryksår, fordi de...... ofte er immobile, har svært ved at opretholde en god siddestilling eller ligger tungt i sengen som følger efter apopleksien Hvis personalet bruger forkert lejrings-og forflytningsteknik, udsættes patienterne for shear og friktion. Målgruppen i projektet er de personer, der omgås patienterne, dvs...

  7. Computerized lateral-shear interferometer

    Science.gov (United States)

    Hasegan, Sorin A.; Jianu, Angela; Vlad, Valentin I.

    1998-07-01

    A lateral-shear interferometer, coupled with a computer for laser wavefront analysis, is described. A CCD camera is used to transfer the fringe images through a frame-grabber into a PC. 3D phase maps are obtained by fringe pattern processing using a new algorithm for direct spatial reconstruction of the optical phase. The program describes phase maps by Zernike polynomials yielding an analytical description of the wavefront aberration. A compact lateral-shear interferometer has been built using a laser diode as light source, a CCD camera and a rechargeable battery supply, which allows measurements in-situ, if necessary.

  8. Comparisons of physical experiment and discrete element simulations of sheared granular materials in an annular shear cell

    Science.gov (United States)

    Ji, S.; Hanes, D.M.; Shen, H.H.

    2009-01-01

    In this study, we report a direct comparison between a physical test and a computer simulation of rapidly sheared granular materials. An annular shear cell experiment was conducted. All parameters were kept the same between the physical and the computational systems to the extent possible. Artificially softened particles were used in the simulation to reduce the computational time to a manageable level. Sensitivity study on the particle stiffness ensured such artificial modification was acceptable. In the experiment, a range of normal stress was applied to a given amount of particles sheared in an annular trough with a range of controlled shear speed. Two types of particles, glass and Delrin, were used in the experiment. Qualitatively, the required torque to shear the materials under different rotational speed compared well with those in the physical experiments for both the glass and the Delrin particles. However, the quantitative discrepancies between the measured and simulated shear stresses were nearly a factor of two. Boundary conditions, particle size distribution, particle damping and friction, including a sliding and rolling, contact force model, were examined to determine their effects on the computational results. It was found that of the above, the rolling friction between particles had the most significant effect on the macro stress level. This study shows that discrete element simulation is a viable method for engineering design for granular material systems. Particle level information is needed to properly conduct these simulations. However, not all particle level information is equally important in the study regime. Rolling friction, which is not commonly considered in many discrete element models, appears to play an important role. ?? 2009 Elsevier Ltd.

  9. Experimental study of a shear wall with numerous small openings

    International Nuclear Information System (INIS)

    Sotomura, K.; Murazumi, Y.; Yoshizaki, S.; Ezaki, T.

    1981-01-01

    Many small openings for piping and ducts are usually required in the shear walls for PWR nuclear power plant. It is generally believed that such openings oadversely affect the strength and stiffness of shear walls. However, little information is available concerning the behavior of walls with numerous small openings. Therefore, tests using wall specimens and an analysis using an FEM program were carried out to investigate this behavior. Main findings are as follows: 1) The ultimate strength of a shear wall with numerous small openings may be obtained by using the effective area at the critical cross section of the shear wall. 2) Shear walls with openings can be restored to the same shear strength and stiffness as shear walls without openings by diagonal reinforcement. (orig./HP)

  10. A new omnidirectional shear horizontal wave transducer using face-shear (d24) piezoelectric ring array.

    Science.gov (United States)

    Miao, Hongchen; Huan, Qiang; Wang, Qiangzhong; Li, Faxin

    2017-02-01

    The non-dispersive fundamental shear horizontal (SH 0 ) wave in plate-like structures is of practical importance in non-destructive testing (NDT) and structural health monitoring (SHM). Theoretically, an omnidirectional SH 0 transducer phased array system can be used to inspect defects in a large plate in the similar manner to the phased array transducers used in medical B-scan ultrasonics. However, very few omnidirectional SH 0 transducers have been proposed so far. In this work, an omnidirectional SH 0 wave piezoelectric transducer (OSH-PT) was proposed, which consists of a ring array of twelve face-shear (d 24 ) trapezoidal PZT elements. Each PZT element can produce face-shear deformation under applied voltage, resulting in circumferential shear deformation in the OSH-PT and omnidirectional SH 0 waves in the hosting plate. Both finite element simulations and experiments were conducted to examine the performance of the proposed OSH-PT. Experimental testing shows that the OSH-PT exhibits good omnidirectional properties, no matter it is used as a SH 0 wave transmitter or a SH 0 wave receiver. This work may greatly promote the applications of SH 0 waves in NDT and SHM. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Shear induced phase transitions induced in edible fats

    Science.gov (United States)

    Mazzanti, Gianfranco; Welch, Sarah E.; Marangoni, Alejandro G.; Sirota, Eric B.; Idziak, Stefan H. J.

    2003-03-01

    The food industry crystallizes fats under different conditions of temperature and shear to obtain products with desired crystalline phases. Milk fat, palm oil, cocoa butter and chocolate were crystallized from the melt in a temperature controlled Couette cell. Synchrotron x-ray diffraction studies were conducted to examine the role of shear on the phase transitions seen in edible fats. The shear forces on the crystals induced acceleration of the alpha to beta-prime phase transition with increasing shear rate in milk fat and palm oil. The increase was slow at low shear rates and became very strong above 360 s-1. In cocoa butter the acceleration between beta-prime-III and beta-V phase transition increased until a maximum of at 360 s-1, and then decreased, showing competition between enhanced heat transfer and viscous heat generation.

  12. Determination of Sediment Profile for 210Pb, Pb, U and Th from Sultan Abu Bakar Dam Due to Soil Erosion from Highland Agriculture Area, Cameron Highlands, Malaysia

    OpenAIRE

    Zaini Hamzah; Seh D. Riduan; Ahmad Saat

    2011-01-01

    Problem statement: Sultan Abu Bakar Dam in Cameron Highlands act as a catchments to accumulate all eroded soil carried by the run off flow through Bertam River, the main river that passes through the highland agriculture area. All suspended solid that carried out by the river contain various kind of hazard potential to the environment. U, Th and Pb are the potential hazard elements carried out by water and accumulate at the dam. Approach: Five sampling point were selected where five 30cm core...

  13. Sense of shear and displacement estimates in the Abeibara-Rarhous late Pan-African shear zone, Adrar des Iforas, Mali

    Science.gov (United States)

    Boullier, Anne-Marie

    The late Pan-African Abeibara-Rarhous shear zone in the Adrar des Iforas (Mali) is described and studied with the aim of defining the direction, sense of movement and amount of displacement along the zone. It is a strike-slip shear zone, the dextral sense of which is demonstrated at the scale of the map by the rotation of the related mylonitic foliation and at the scale of the thin section with characteristic microstructures. Preferred orientation of quartz c-axes is tentatively used; three quartz-rich samples of 35% or more quartz indicate dextral strike-slip movement, but other samples do not show preferred orientation of quartz c-axes. Strain measurements have been performed on one half of the shear zone using established techniques and a new technique using the thickness of mylonitic layering. The results vary along the length of the shear zone when using the same method and for the same cross-section when using the three methods together. A mean value of 4 km is obtained for total displacement which is low when considering the apparent width of the shear zone. This result is discussed in view of the assumptions involved in the strain estimation. The tectonic history of the Abeibara-Rarhous shear zone and its significance in the Trans-Saharan Pan-African collisional belt are discussed.

  14. KATALIS HETEROGEN DARI ABU VULKANIK UNTUK PEMBUATAN BIODIESEL DARI MINYAK MIKROALGA CHLORELLA SP

    Directory of Open Access Journals (Sweden)

    Catur Rini Widyastuti

    2014-02-01

    Full Text Available Selama ini, proses produksi biodiesel konvensioanal banyak menghasilkan air limbah pada tahap pemisahan produk dari katalis yang larut dan produk samping yang dihasilkan. Oleh karena itu, untuk mengurangi limbah yang dihasilkan selama proses pemisahan tersebut, jenis katalis heterogen dapat digunakan untuk menggantikan katalis homogen alkali yang biasa digunakan. Penelitian ini bertujuan untuk mengkaji jenis katalis dan aktivitasnya dalam reaksi transesterifikasi minyak mikroalga Chlorella sp menjadi biodiesel. Tahap awal penelitian yang dilakukan adalah preparasi minyak mikroalga yang akan digunakan untuk uji aktivitas katalis. Minyak mikroalga diperoleh dengan ekstraksi menggunakan metode maserasi menggunakan pelarut n-heksana. Rendemen minyak yang diperoleh sebesar 12,26%. Dari hasil uji GC-MS diketahui dua kandungan asam lemak terbesar dalam minyak mikroalga, yaitu Dodecanoic acid sebesar 59.52% dan n-Decanoic acid sebesar 12.64%. Selanjutnya minyak mikroalga direaksikan dengan metanol dengan rasio molar 1:6 menggunakan katalis yang disintesis dari abu vulkanik. Preparasi katalis dilakukan dengan dua metode yang berbeda, yaitu refluks dengan larutan H 2 SO 2 M dan secara alkali hidrotermal menggunakan larutan NaOH 2M. Reaksi transesterifikasi berlangsung pada suhu 60 o 4 C dengan penambahan katalis padat sebanyak 5% selama 60 menit. Yield biodiesel yang diperoleh dari reaksi menggunakan katalis yang dipreparasi dengan larutan H 2 SO adalah 28,27% dengan densitas 0,684 g/ mL. Sedangkan reaksi dengan katalis yang dipreparasi secara alkali hidrotermal menghasilkan biodiesel sebanyak 23% dengan densitas 0,69 g/mL.

  15. Microalga propels along vorticity direction in a shear flow

    Science.gov (United States)

    Chengala, Anwar; Hondzo, Miki; Sheng, Jian

    2013-05-01

    Using high-speed digital holographic microscopy and microfluidics, we discover that, when encountering fluid flow shear above a threshold, unicellular green alga Dunaliella primolecta migrates unambiguously in the cross-stream direction that is normal to the plane of shear and coincides with the local fluid flow vorticity. The flow shear drives motile microalgae to collectively migrate in a thin two-dimensional horizontal plane and consequently alters the spatial distribution of microalgal cells within a given suspension. This shear-induced algal migration differs substantially from periodic rotational motion of passive ellipsoids, known as Jeffery orbits, as well as gyrotaxis by bottom-heavy swimming microalgae in a shear flow due to the subtle interplay between torques generated by gravity and viscous shear. Our findings could facilitate mechanistic solutions for modeling planktonic thin layers and sustainable cultivation of microalgae for human nutrition and bioenergy feedstock.

  16. Critical wall shear stress for the EHEDG test method

    DEFF Research Database (Denmark)

    Jensen, Bo Boye Busk; Friis, Alan

    2004-01-01

    In order to simulate the results of practical cleaning tests on closed processing equipment, based on wall shear stress predicted by computational fluid dynamics, a critical wall shear stress is required for that particular cleaning method. This work presents investigations that provide a critical...... wall shear stress of 3 Pa for the standardised EHEDG cleaning test method. The cleaning tests were performed on a test disc placed in a radial flowcell assay. Turbulent flow conditions were generated and the corresponding wall shear stresses were predicted from CFD simulations. Combining wall shear...... stress predictions from a simulation using the low Re k-epsilon and one using the two-layer model of Norris and Reynolds were found to produce reliable predictions compared to empirical solutions for the ideal flow case. The comparison of wall shear stress curves predicted for the real RFC...

  17. Effect of rock joint roughness on its cyclic shear behavior

    Directory of Open Access Journals (Sweden)

    S.M. Mahdi Niktabar

    2017-12-01

    Full Text Available Rock joints are often subjected to dynamic loads induced by earthquake and blasting during mining and rock cutting. Hence, cyclic shear load can be induced along the joints and it is important to evaluate the shear behavior of rock joint under this condition. In the present study, synthetic rock joints were prepared with plaster of Paris (PoP. Regular joints were simulated by keeping regular asperity with asperity angles of 15°–15° and 30°–30°, and irregular rock joints which are closer to natural joints were replicated by keeping the asperity angles of 15°–30° and 15°–45°. The sample size and amplitude of roughness were kept the same for both regular and irregular joints which were 298 mm × 298 mm × 125 mm and 5 mm, respectively. Shear test was performed on these joints using a large-scale direct shear testing machine by keeping the frequency and amplitude of shear load under constant cyclic condition with different normal stress values. As expected, the shear strength of rock joints increased with the increases in the asperity angle and normal load during the first cycle of shearing or static load. With the increase of the number of shear cycles, the shear strength decreased for all the asperity angles but the rate of reduction was more in case of high asperity angles. Test results indicated that shear strength of irregular joints was higher than that of regular joints at different cycles of shearing at low normal stress. Shearing and degradation of joint asperities on regular joints were the same between loading and unloading, but different for irregular joints. Shear strength and joint degradation were more significant on the slope of asperity with higher angles on the irregular joint until two angles of asperities became equal during the cycle of shearing and it started behaving like regular joints for subsequent cycles.

  18. Abu-Sahl al-Masihi (died circa 1010 AD): The Persian physician in the early medieval era.

    Science.gov (United States)

    Taghavi-Shirazi, Maryam; Ghods, Roshanak; Hashem-Dabaghian, Fataneh; Zargaran, Arman

    2018-01-01

    In the early medieval era, in the time which is called the Islamic Golden Age, medicine flourished through the practice of Persian physicians (9th to 12th century AD). Abu-Sahl al-Masihi (died circa 1010 AD) was one of the physicians in that period who had great influence on the progress of medicine by his own writings as well as his influence on great scholars like Biruni and Avicenna as their teacher. He was a polymath and had many writings in various fields of science, in particular medical sciences. Some of his manuscripts in medicine were Al-Mia fil-Tibb (Book of the Hundred), Kitab al-Teb al-Koli (The General Medicine), Ezhar al-Hekmat Allah Ta'ala fi Khalgh al-Ensan (God's Mystery on the Creation of Man), Resalat al-Adwiya (Treatise of Drugs), Osool Elm Nabz (the Principles of Pulse), and Resala f ī Taḥqiq Amral-Waba' (On the determination of the matter of infectious diseases). As a sign of his impact in Persian medicine, many later physicians (until 19th century) referred to and cited his works in their manuscripts several times.

  19. Gravity and Areomagnetic Signatures and their Geological Significance in the Abu Gharadig Basin, Nortwestern Desert, Egypt

    International Nuclear Information System (INIS)

    Ibrahim, H.A.

    2000-01-01

    Geological interpretation of Bouguer gravity anomalies and total intensity magnetic anomalies of two profiles from the Abu Gharadig Basin suggests a general northward increase in basement depth (about 3 to 6 km). Gravity modeling using software given by Enmark (1981) and Beg et. al (1987) are applied along the gravity profiles, giving reliable results agreeing with the available geological information on the area. The magenetic profiles are interpreted and analyzed using two methods: non-linear optimization techniques and interactive techniques. A prominent uplift of the basement rock is observed to the south, which is considered a part of the major basement high in the north Western Desert of the Egypt. In addition a significant deepning of the basement is found to the north, which represents a part of the major subsidence including the present Mediterranean BasinThe abnormal thickness of the sedimentary section of varius facies, and the presence of deep-causative intrabasement (acidic or basic bodies) are possibly considered the main cause for 1) the origin of different gravity anamolies (negative and positive respectively); and 2) the origin of different magnetic anomalies (low and high), particularly those in the middle part of the study area. (author)

  20. Tensile and shear strength of adhesives

    Science.gov (United States)

    Stibolt, Kenneth A.

    1990-01-01

    This experiment is conducted in a freshman-level course: Introduction to Engineering Materials. There are no prerequisites for the course although students should have some knowledge of basic algebra. The objectives are to tension and shear test adhesives and to determine the tensile and shear properties of adhesives. Details of equipment of procedure are given.

  1. Thermal convection of viscoelastic shear-thinning fluids

    International Nuclear Information System (INIS)

    Albaalbaki, Bashar; Khayat, Roger E; Ahmed, Zahir U

    2016-01-01

    The Rayleigh–Bénard convection for non-Newtonian fluids possessing both viscoelastic and shear-thinning behaviours is examined. The Phan-Thien–Tanner (PTT) constitutive equation is implemented to model the non-Newtonian character of the fluid. It is found that while the shear-thinning and viscoelastic effects could annihilate one another for the steady roll flow, presence of both behaviours restricts the roll stability limit significantly compared to the cases when the fluid is either inelastic shear-thinning or purely viscoelastic with constant viscosity. (paper)

  2. Size effects in shear interfaces

    OpenAIRE

    GARNIER, J

    2001-01-01

    In physical modelling (centrifuge tests, calibration chambers, laboratory tests), the size of the soil particles may not be negligible when compared to the dimensions of the models. Size effects may so disturb the response of the models and the experimental data obtained on these cannot be extended to true scale conditions. Different tests have been performed to study and quantify the size effects that may happen in shear interfaces between soils and structures : modified shear box tests, pul...

  3. Shear Alfven waves in tokamaks

    International Nuclear Information System (INIS)

    Kieras, C.E.

    1982-12-01

    Shear Alfven waves in an axisymmetric tokamak are examined within the framework of the linearized ideal MHD equations. Properties of the shear Alfven continuous spectrum are studied both analytically and numerically. Implications of these results in regards to low frequency rf heating of toroidally confined plasmas are discussed. The structure of the spatial singularities associated with these waves is determined. A reduced set of ideal MHD equations is derived to describe these waves in a very low beta plasma

  4. Shear Tests and Calculation of Shear Resistance with the PC Program RFEM from Thin Partition Walls of Brick in Old Buildings

    Directory of Open Access Journals (Sweden)

    Korjenic Sinan

    2015-11-01

    Full Text Available This paper is about the shear capacity of partition walls in old buildings based on shear tests which were carried out under real conditions in an existing building. There were experiments conducted on different floors and in each case, the maximum recordable horizontal force and the horizontal displacement of the respective mortar were measured. At the same time material studies and material investigations were carried out in the laboratory. The material parameters were used for the calculation of the precise shear capacity of each joint. In the shear tests, the maximum displacement of a mortar joint was determined at a maximum of two to four millimetres. Furthermore, no direct linear relationship between the theoretical load (wall above it and the shear stress occurred could be detected in the analysis of the experiment, as it was previously assumed.

  5. Shear Tests and Calculation of Shear Resistance with the PC Program RFEM from Thin Partition Walls of Brick in Old Buildings

    Science.gov (United States)

    Korjenic, Sinan; Nowak, Bernhard; Löffler, Philipp; Vašková, Anna

    2015-11-01

    This paper is about the shear capacity of partition walls in old buildings based on shear tests which were carried out under real conditions in an existing building. There were experiments conducted on different floors and in each case, the maximum recordable horizontal force and the horizontal displacement of the respective mortar were measured. At the same time material studies and material investigations were carried out in the laboratory. The material parameters were used for the calculation of the precise shear capacity of each joint. In the shear tests, the maximum displacement of a mortar joint was determined at a maximum of two to four millimetres. Furthermore, no direct linear relationship between the theoretical load (wall above it) and the shear stress occurred could be detected in the analysis of the experiment, as it was previously assumed.

  6. FEM Simulation of Incremental Shear

    International Nuclear Information System (INIS)

    Rosochowski, Andrzej; Olejnik, Lech

    2007-01-01

    A popular way of producing ultrafine grained metals on a laboratory scale is severe plastic deformation. This paper introduces a new severe plastic deformation process of incremental shear. A finite element method simulation is carried out for various tool geometries and process kinematics. It has been established that for the successful realisation of the process the inner radius of the channel as well as the feeding increment should be approximately 30% of the billet thickness. The angle at which the reciprocating die works the material can be 30 deg. . When compared to equal channel angular pressing, incremental shear shows basic similarities in the mode of material flow and a few technological advantages which make it an attractive alternative to the known severe plastic deformation processes. The most promising characteristic of incremental shear is the possibility of processing very long billets in a continuous way which makes the process more industrially relevant

  7. Benefits of a single payment system: case study of Abu Dhabi health system reforms.

    Science.gov (United States)

    Vetter, Philipp; Boecker, Klaus

    2012-12-01

    In 2005 leaders in the wealthy Emirate of Abu Dhabi inherited an health system from their predecessors that was well-intentioned in its historic design, but that did not live up to aspirations in any dimension. First, the Emirate defined a vision to deliver "world-class" quality care in response to citizen's needs. It has since introduced tiered mandatory health insurance for all inhabitants linked to a single standard payment system, which generates accurate data as an invaluable by-product. A newly created independent health system regulator monitors these data and licenses, audits, and inspects all health service professionals, facilities, and insurers accordingly. We analyse these health system reforms using the "Getting Health Reform Right" framework. Our analysis suggests that an integrated set of reforms addressing all reform levers is critical to achieving the outcomes observed. The reform programme has improved access, by giving all residents health cards. The approximate doubling of demand has been matched by flexible supply, with the private sector adding 5 new hospitals and 93 clinics to the health system infrastructure since 2006. The focus on reliable raw-data flows through the single standard payment system functions as a motor for improvement services, innovation, and investment, for instance by allowing payers to 'pay for quality', which may well be applicable in other contexts. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  8. How shear increments affect the flow production branching ratio in CSDX

    Science.gov (United States)

    Li, J. C.; Diamond, P. H.

    2018-06-01

    The coupling of turbulence-driven azimuthal and axial flows in a linear device absent magnetic shear (Controlled Shear Decorrelation Experiment) is investigated. In particular, we examine the apportionment of Reynolds power between azimuthal and axial flows, and how the azimuthal flow shear affects axial flow generation and saturation by drift wave turbulence. We study the response of the energy branching ratio, i.e., ratio of axial and azimuthal Reynolds powers, PzR/PyR , to incremental changes of azimuthal and axial flow shears. We show that increasing azimuthal flow shear decreases the energy branching ratio. When axial flow shear increases, this ratio first increases but then decreases to zero. The axial flow shear saturates below the threshold for parallel shear flow instability. The effects of azimuthal flow shear on the generation and saturation of intrinsic axial flows are analyzed. Azimuthal flow shear slows down the modulational growth of the seed axial flow shear, and thus reduces intrinsic axial flow production. Azimuthal flow shear reduces both the residual Reynolds stress (of axial flow, i.e., ΠxzR e s ) and turbulent viscosity ( χzDW ) by the same factor |⟨vy⟩'|-2Δx-2Ln-2ρs2cs2 , where Δx is the distance relative to the reference point where ⟨vy⟩=0 in the plasma frame. Therefore, the stationary state axial flow shear is not affected by azimuthal flow shear to leading order since ⟨vz⟩'˜ΠxzR e s/χzDW .

  9. Shear Stress-Relative Slip Relationship at Concrete Interfaces

    Directory of Open Access Journals (Sweden)

    Keun-Hyeok Yang

    2016-01-01

    Full Text Available This study develops a simple and rational shear stress-relative slip model of concrete interfaces with monolithic castings or smooth construction joints. In developing the model, the initial shear cracking stress and relative slip amount at peak stress were formulated from a nonlinear regression analysis using test data for push-off specimens. The shear friction strength was determined from the generalized equations on the basis of the upper-bound theorem of concrete plasticity. Then, a parametric fitting analysis was performed to derive equations for the key parameters determining the shapes of the ascending and descending branches of the shear stress-relative slip curve. The comparisons of predictions and measurements obtained from push-off tests confirmed that the proposed model provides superior accuracy in predicting the shear stress-relative slip relationship of interfacial shear planes. This was evidenced by the lower normalized root mean square error than those in Xu et al.’s model and the CEB-FIB model, which have many limitations in terms of the roughness of the substrate surface along an interface and the magnitude of equivalent normal stress.

  10. Probabilistic Cosmological Mass Mapping from Weak Lensing Shear

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M. D.; Dawson, W. A. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Ng, K. Y. [University of California, Davis, Davis, CA 95616 (United States); Marshall, P. J. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94035 (United States); Meyers, J. E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Bard, D. J., E-mail: schneider42@llnl.gov, E-mail: dstn@cmu.edu, E-mail: boutigny@in2p3.fr, E-mail: djbard@slac.stanford.edu, E-mail: jmeyers314@stanford.edu [National Energy Research Scientific Computing Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720-8150 (United States)

    2017-04-10

    We infer gravitational lensing shear and convergence fields from galaxy ellipticity catalogs under a spatial process prior for the lensing potential. We demonstrate the performance of our algorithm with simulated Gaussian-distributed cosmological lensing shear maps and a reconstruction of the mass distribution of the merging galaxy cluster Abell 781 using galaxy ellipticities measured with the Deep Lens Survey. Given interim posterior samples of lensing shear or convergence fields on the sky, we describe an algorithm to infer cosmological parameters via lens field marginalization. In the most general formulation of our algorithm we make no assumptions about weak shear or Gaussian-distributed shape noise or shears. Because we require solutions and matrix determinants of a linear system of dimension that scales with the number of galaxies, we expect our algorithm to require parallel high-performance computing resources for application to ongoing wide field lensing surveys.

  11. Stabilization of ballooning modes with sheared toroidal rotation

    International Nuclear Information System (INIS)

    Miller, R.L.; Waelbroeck, F.L.; Hassam, A.B.; Waltz, R.E.

    1995-01-01

    Stabilization of magnetohydrodynamic ballooning modes by sheared toroidal rotation is demonstrated using a shifted circle equilibrium model. A generalized ballooning mode representation is used to eliminate the fast Alfven wave, and an initial value code solves the resulting equations. The s-α diagram (magnetic shear versus pressure gradient) of ballooning mode theory is extended to include rotational shear. In the ballooning representation, the modes shift periodically along the field line to the next point of unfavorable curvature. The shift frequency (dΩ/dq, where Ω is the angular toroidal velocity and q is the safety factor) is proportional to the rotation shear and inversely proportional to the magnetic shear. Stability improves with increasing shift frequency and direct stable access to the second stability regime occurs when this frequency is approximately one-quarter to one-half the Alfven frequency, ω A =V A /qR. copyright 1995 American Institute of Physics

  12. Delayed shear enhancement in mesoscale atmospheric dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Moran, M.D. [Atmospheric Environment Service, Ontario (Canada); Pielke, R.A. [Colorado State Univ., Fort Collins, CO (United States)

    1994-12-31

    Mesoscale atmospheric dispersion (MAD) is more complicated than smaller-scale dispersion because the mean wind field can no longer be considered steady or horizontally homogeneous over mesoscale time and space scales. Wind shear also plays a much more important role on the mesoscale: horizontal dispersion can be enhanced and often dominated by vertical wind shear on these scales through the interaction of horizontal differential advection and vertical mixing. Just over 30 years ago, Pasquill suggested that this interaction need not be simultaneous and that the combination of differential horizontal advection with delayed or subsequent vertical mixing could maintain effective horizontal diffusion in spite of temporal or spatial reductions in boundary-layer turbulence intensity. This two-step mechanism has not received much attention since then, but a recent analysis of observations from and numerical simulations of two mesoscale tracer experiments suggests that delayed shear enhancement can play an important role in MAD. This paper presents an overview of this analysis, with particular emphasis on the influence of resolvable vertical shear on MAD in these two case studies and the contributions made by delayed shear enhancement.

  13. Shear strength behavior of geotextile/geomembrane interfaces

    Directory of Open Access Journals (Sweden)

    Belén M. Bacas

    2015-12-01

    Full Text Available This paper aims to study the shear interaction mechanism of one of the critical geosynthetic interfaces, the geotextile/geomembrane, typically used for lined containment facilities such as landfills. A large direct shear machine is used to carry out 90 geosynthetic interface tests. The test results show a strain softening behavior with a very small dilatancy (<0.5 mm and nonlinear failure envelopes at a normal stress range of 25–450 kPa. The influences of the micro-level structure of these geosynthetics on the macro-level interface shear behavior are discussed in detail. This study has generated several practical recommendations to help professionals to choose what materials are more adequate. From the three geotextiles tested, the thermally bonded monofilament exhibits the best interface shear strength under high normal stress. For low normal stress, however, needle-punched monofilaments are recommended. For the regular textured geomembranes tested, the space between the asperities is an important factor. The closer these asperities are, the better the result achieves. For the irregular textured geomembranes tested, the nonwoven geotextiles made of monofilaments produce the largest interface shear strength.

  14. Significance of Shear Wall in Multi-Storey Structure With Seismic Analysis

    Science.gov (United States)

    Bongilwar, Rajat; Harne, V. R.; Chopade, Aditya

    2018-03-01

    In past decades, shear walls are one of the most appropriate and important structural component in multi-storied building. Therefore, it would be very interesting to study the structural response and their systems in multi-storied structure. Shear walls contribute the stiffness and strength during earthquakes which are often neglected during design of structure and construction. This study shows the effect of shear walls which significantly affect the vulnerability of structures. In order to test this hypothesis, G+8 storey building was considered with and without shear walls and analyzed for various parameters like base shear, storey drift ratio, lateral displacement, bending moment and shear force. Significance of shear wall has been studied with the help of two models. First model is without shear wall i.e. bare frame and other another model is with shear wall considering opening also in it. For modeling and analysis of both the models, FEM based software ETABS 2016 were used. The analysis of all models was done using Equivalent static method. The comparison of results has been done based on same parameters like base shear, storey drift ratio, lateral displacement, bending moment and shear force.

  15. Meniscal shear stress for punching.

    Science.gov (United States)

    Tuijthof, Gabrielle J M; Meulman, Hubert N; Herder, Just L; van Dijk, C Niek

    2009-01-01

    Experimental determination of the shear stress for punching meniscal tissue. Meniscectomy (surgical treatment of a lesion of one of the menisci) is the most frequently performed arthroscopic procedure. The performance of a meniscectomy is not optimal with the currently available instruments. To design new instruments, the punching force of meniscal tissue is an important parameter. Quantitative data are unavailable. The meniscal punching process was simulated by pushing a rod through meniscal tissue at constant speed. Three punching rods were tested: a solid rod of Oslash; 3.00 mm, and two hollow tubes (Oslash; 3.00-2.60 mm) with sharpened cutting edges of 0.15 mm and 0.125 mm thick, respectively. Nineteen menisci acquired from 10 human cadaveric knee joints were punched (30 tests). The force and displacement were recorded from which the maximum shear stress was determined (average added with three times the standard deviation). The maximum shear stress for the solid rod was determined at 10.2 N/mm2. This rod required a significantly lower punch force in comparison with the hollow tube having a 0.15 mm cutting edge (plt;0.01). The maximum shear stress for punching can be applied to design instruments, and virtual reality training environments. This type of experiment is suitable to form a database with material properties of human tissue similar to databases for the manufacturing industry.

  16. Examining shear processes during magma ascent

    Science.gov (United States)

    Kendrick, J. E.; Wallace, P. A.; Coats, R.; Lamur, A.; Lavallée, Y.

    2017-12-01

    Lava dome eruptions are prone to rapid shifts from effusive to explosive behaviour which reflects the rheology of magma. Magma rheology is governed by composition, porosity and crystal content, which during ascent evolves to yield a rock-like, viscous suspension in the upper conduit. Geophysical monitoring, laboratory experiments and detailed field studies offer the opportunity to explore the complexities associated with the ascent and eruption of such magmas, which rest at a pivotal position with regard to the glass transition, allowing them to either flow or fracture. Crystal interaction during flow results in strain-partitioning and shear-thinning behaviour of the suspension. In a conduit, such characteristics favour the formation of localised shear zones as strain is concentrated along conduit margins, where magma can rupture and heal in repetitive cycles. Sheared magmas often record a history of deformation in the form of: grain size reduction; anisotropic permeable fluid pathways; mineral reactions; injection features; recrystallisation; and magnetic anomalies, providing a signature of the repetitive earthquakes often observed during lava dome eruptions. The repetitive fracture of magma at ( fixed) depth in the conduit and the fault-like products exhumed at spine surfaces indicate that the last hundreds of meters of ascent may be controlled by frictional slip. Experiments on a low-to-high velocity rotary shear apparatus indicate that shear stress on a slip plane is highly velocity dependent, and here we examine how this influences magma ascent and its characteristic geophysical signals.

  17. Residual shear strength of a severely ASR-damaged flat slab bridge

    DEFF Research Database (Denmark)

    Barbosa, Ricardo Antonio; Gustenhoff Hansen, Søren; Hoang, Linh Cao

    2018-01-01

    moment carried by the beams. For the beams tested in asymmetric four-point bending, an increase in the shear span-to-effective depth ratio resulted in a decrease in the measured shear strength. The measured shear strengths were compared with calculated shear strengths using the Eurocode 2. Calculations...... based on the compressive strength of drilled cores were rather conservative at low shear span-to-effective depth ratios. However, the conservatism of the Eurocode 2 decreased with increasing shear span-to-effective depth ratios. With the inclusion of ASR-induced pre-stress effect, the calculated shear...... strengths correlated better with the measured shear strengths. The test results indicated that the ASR-induced pre-stress effect can, to some extent, compensate for the significant loss in material properties....

  18. Implementation of improved underbalanced drilling in AbuDhabi onshore field

    Science.gov (United States)

    Alhammadi, Adel Mohammed

    Abu Dhabi Company for Onshore Oil Operations (ADCO) is considering Underbalanced Drilling (UBD) as a means to develop lower permeability units in its fields. In addition to productivity and recovery gains, ADCO also expects reservoir characterization benefits from UBD. Reservoir screening studies were carried out on all of ADCO's reservoirs to determine their applicability for UBD. The primary business benefits of UBD were determined to be reservoir characterization, damage Mitigation, and rate of Penetration "ROP" Improvement. Apart from the primary benefits, some of the secondary benefits of UBD that were identified beforehand included rig performance. Since it's a trial wells, the challenge was to drill these wells safely, efficiently and of course meeting well objectives. Many operators worldwide drill these well in underbalanced mode but complete it overbalanced. In our case the plan was to drill and complete these wells in underbalanced condition. But we had to challenge most operators and come up with special and unique casing hanger design to ensure well control barriers exists while fishing the control line of the Downhole Deployment Valve "DDV". After intensive studies and planning, the hanger was designed as per our recommendations and found to be effective equipment that optimized the operational time and the cost as well. This report will provide better understanding of UBD technique in general and shade on the special designed casing hanger compared to conventional or what's most used worldwide. Even thought there were some issues while running the casing hanger prior drilling but managed to capture the learning's from each well and re-modified the hanger and come up with better deign for the future wells. Finally, the new design perform a good performance of saving the operation time and assisting the project to be done in a safe and an easy way without a major impact on the well cost. This design helped to drill and complete these wells safely with

  19. Rating precast prestressed concrete bridges for shear

    Science.gov (United States)

    2008-12-01

    Shear capacity of real-world prestressed concrete girders designed in the 1960s and 1970s is a concern because : AASHTO Standard Specifications (AASHTO-STD) employed the quarter-point rule for shear design, which is less : conservative for shea...

  20. High shear microfluidics and its application in rheological measurement

    Science.gov (United States)

    Kang, Kai; Lee, L. James; Koelling, Kurt W.

    2005-02-01

    High shear rheology was explored experimentally in microchannels (150×150 μm). Two aqueous polymer solutions, polyethylene oxide (viscoelastic fluid) and hydroxyethyl cellulose (viscous fluid) were tested. Bagley correction was applied to remove the end effect. Wall slip was investigated with Mooney’s analysis. Shear rates as high as 106 s-1 were obtained in the pressure-driven microchannel flow, allowing a smooth extension of the low shear rheological data obtained from the conventional rheometers. At high shear rates, polymer degradation was observed for PEO solutions at a critical microchannel wall shear stress of 4.1×103 Pa. Stresses at the ends of the microchannel also contributed to PEO degradation significantly.

  1. Micromechanics of soil responses in cyclic simple shear tests

    Directory of Open Access Journals (Sweden)

    Cui Liang

    2017-01-01

    Full Text Available Offshore wind turbine (OWT foundations are subjected to a combination of cyclic and dynamic loading arising from wind, wave, rotor and blade shadowing. Under cyclic loading, most soils change their characteristics including stiffness, which may cause the system natural frequency to approach the loading frequency and lead to unplanned resonance and system damage or even collapse. To investigate such changes and the underlying micromechanics, a series of cyclic simple shear tests were performed on the RedHill 110 sand with different shear strain amplitudes, vertical stresses and initial relative densities of soil. The test results showed that: (a Vertical accumulated strain is proportional to the shear strain amplitude but inversely proportional to relative density of soil; (b Shear modulus increases rapidly in the initial loading cycles and then the rate of increase diminishes and the shear modulus remains below an asymptote; (c Shear modulus increases with increasing vertical stress and relative density, but decreasing with increasing strain amplitude. Coupled DEM simulations were performed using PFC2D to analyse the micromechanics underlying the cyclic behaviour of soils. Micromechanical parameters (e.g. fabric tensor, coordination number were examined to explore the reasons for the various cyclic responses to different shear strain amplitudes or vertical stresses. Both coordination number and magnitude of fabric anisotropy contribute to the increasing shear modulus.

  2. Estimated strength of shear keys in concrete dams

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, D.D. [Hatch Energy, Niagara Falls, ON (Canada); Lum, K.K.Y. [BC Hydro, Burnaby, BC (Canada)

    2008-07-01

    BC Hydro requested that Hatch Energy review the seismic stability of Ruskin Dam which was constructed in 1930 at Hayward Lake in British Columbia. The concrete gravity dam is founded nearly entirely on rock in a narrow valley. The vertical joints between blocks are keyed and grouted. The strength of the shear keys was assessed when a non-linear finite element model found that significant forces were being transferred laterally to the abutments during an earthquake. The lateral transfer of loads to the abutment relies on the strength of the shear keys. The dynamic finite element analysis was used to determine the stability of the dam. A review of the shear strength measurements reported in literature showed that the measurements compared well to those obtained by BC Hydro from cores taken from Ruskin Dam. The cohesive strength obtained using the Griffith failure criteria was also in good agreement with both sets of measurements. A simple ultimate shear strength equation was developed using the Mohr-Coulomb failure criteria to determine combined cohesive and frictional strength of shear keys. Safety factors of 2.0 for static loads and 1.5 for seismic loads were proposed to reduce the ultimate strength to allowable values. It was concluded that given the relatively high shear strength established for the shear keys, the abutment rock or dam/abutment contact will control the amount of load which can arch to the abutments. 8 refs., 4 tabs., 5 figs.

  3. Experimental study of the vortex-induced vibration of drilling risers under the shear flow with the same shear parameter at the different Reynolds numbers.

    Science.gov (United States)

    Liangjie, Mao; Qingyou, Liu; Shouwei, Zhou

    2014-01-01

    A considerable number of studies for VIV under the uniform flow have been performed. However, research on VIV under shear flow is scarce. An experiment for VIV under the shear flow with the same shear parameter at the two different Reynolds numbers was conducted in a deep-water offshore basin. Various measurements were obtained by the fiber bragg grating strain sensors. Experimental data were analyzed by modal analysis method. Results show several valuable features. First, the corresponding maximum order mode of the natural frequency for shedding frequency is the maximum dominant vibration mode and multi-modal phenomenon is appeared in VIV under the shear flow, and multi-modal phenomenon is more apparent at the same shear parameter with an increasing Reynolds number under the shear flow effect. Secondly, the riser vibrates at the natural frequency and the dominant vibration frequency increases for the effect of the real-time tension amplitude under the shear flow and the IL vibration frequency is the similar with the CF vibration frequency at the Reynolds number of 1105 in our experimental condition and the IL dominant frequency is twice the CF dominant frequency with an increasing Reynolds number. In addition, the displacement trajectories at the different locations of the riser appear the same shape and the shape is changed at the same shear parameter with an increasing Reynolds number under the shear flow. The diagonal displacement trajectories are observed at the low Reynolds number and the crescent-shaped displacement trajectories appear with an increasing Reynolds number under shear flow in the experiment.

  4. Experimental study of the vortex-induced vibration of drilling risers under the shear flow with the same shear parameter at the different Reynolds numbers.

    Directory of Open Access Journals (Sweden)

    Mao Liangjie

    Full Text Available A considerable number of studies for VIV under the uniform flow have been performed. However, research on VIV under shear flow is scarce. An experiment for VIV under the shear flow with the same shear parameter at the two different Reynolds numbers was conducted in a deep-water offshore basin. Various measurements were obtained by the fiber bragg grating strain sensors. Experimental data were analyzed by modal analysis method. Results show several valuable features. First, the corresponding maximum order mode of the natural frequency for shedding frequency is the maximum dominant vibration mode and multi-modal phenomenon is appeared in VIV under the shear flow, and multi-modal phenomenon is more apparent at the same shear parameter with an increasing Reynolds number under the shear flow effect. Secondly, the riser vibrates at the natural frequency and the dominant vibration frequency increases for the effect of the real-time tension amplitude under the shear flow and the IL vibration frequency is the similar with the CF vibration frequency at the Reynolds number of 1105 in our experimental condition and the IL dominant frequency is twice the CF dominant frequency with an increasing Reynolds number. In addition, the displacement trajectories at the different locations of the riser appear the same shape and the shape is changed at the same shear parameter with an increasing Reynolds number under the shear flow. The diagonal displacement trajectories are observed at the low Reynolds number and the crescent-shaped displacement trajectories appear with an increasing Reynolds number under shear flow in the experiment.

  5. Velocity shear generated Alfven waves in electron-positron plasmas

    International Nuclear Information System (INIS)

    Rogava, A.D.; Berezhiani, V.I.; Mahajan, S.M.

    1996-01-01

    Linear MHD modes in cold, nonrelativistic electron-positron plasma shear flow are considered. The general set of differential equations, describing the evolution of perturbations in the framework of the nonmodal approach is derived. It is found, that under certain circumstances, the compressional and shear Alfven perturbations may exhibit large transient growth fuelled by the mean kinetic energy of the shear flow. The velocity shear also induces mode coupling allowing the exchange of energy as well as the possibility of a strong mutual transformation of these modes into each other. The compressional Alfven mode may extract the energy of the mean flow and transfer it to the shear Alfven mode via this coupling. The relevance of these new physical effects to provide a better understanding of the laboratory e + e - plasma is emphasized. It is speculated that the shear-induced effects in the electron-positron plasmas could also help solve some astrophysical puzzles (e.g., the generation of pulsar radio emission). Since most astrophysical plasma are relativistic, it is shown that the major results of the study remain valid for weakly sheared relativistic plasmas. (author). 21 refs, 4 figs

  6. Triglyceride glucose index and common carotid wall shear stress.

    Science.gov (United States)

    Tripolino, Cesare; Irace, Concetta; Scavelli, Faustina B; de Franceschi, Maria S; Esposito, Teresa; Carallo, Claudio; Gnasso, Agostino

    2014-02-01

    Alterations in wall shear stress contribute to both clinical and subclinical atherosclerosis. Several conditions such as hypertension, diabetes, and obesity can impair shear stress, but the role of insulin resistance has never been investigated. The present study was designed to investigate whether insulin resistance assessed by TyG Index associates with wall shear stress in the common carotid artery. One hundred six individuals were enrolled. Blood pressure, lipids, glucose, and cigarette smoking were evaluated. TyG Index was calculated as log[fasting triglycerides × fasting glucose / 2]. Subjects underwent blood viscosity measurement and echo-Doppler evaluation of carotid arteries to calculate wall shear stress. The association between TyG Index and carotid wall shear stress was assessed by simple and multiple regression analyses. TyG Index was significantly and inversely associated with carotid wall shear stress both in simple (r = -0.44, P glucose greater than 100 mg/dL, and triglycerides greater than 150 mg/dL. The present findings suggest that increasing insulin resistance, as assessed by TyG Index, associates with atherosclerosis-prone shear stress reduction in the common carotid artery.

  7. Abu Bakr Qalandar. Qalandar-name. Chapter 9. “The Ascension (Mi’raj of the Messenger [of Allah] (Peace Be upon Him!”.

    Directory of Open Access Journals (Sweden)

    Ismagil R. Gibadullin

    2016-12-01

    Full Text Available This article contains an excerpt from the poem “Qalandar-name” of Sufi sheikh and Islamic scholar of Anatolian origin, Abu Bakr Qalandar Rumi, who lived in Crimea. The ninth chapter is devoted to the ascension of the Prophet of Islam, Muhammad (peace be upon him!, which is known as the Mi’raj in the Islamic tradition. This chapter is full of highly emotional and mystical reflections on the significance of this event. This topic becomes particularly meaningful in the context of religious and mystical work “Qalandar-name”. It points to a shift from the traditional expressions of honor with respect to the primary figures of early Islamic history (righteous Caliphs, relatives of the Prophet, Imams of four Sunni madhhabs to the presentation of mystical revelations and experiences of the author.

  8. Determination of lead, mercury and cadmium concentrations in different organs of Barbus grypus and Liza abu of Karoon River in 2011

    Directory of Open Access Journals (Sweden)

    A ghorbani ranjbary

    2013-02-01

    Full Text Available Accumulation of heavy metals in fish body causes the destruction of soft tissues and suppression of immune system. Moreover, consumption of contaminated fish causes several consequences in humans. This survey was conducted to determine the concentration of lead, mercury and cadmium in muscle tissue, gill as well as liver of Barbus grypus and Liza abu. These two species are native fishes of Karoon River in Ahvaz area. A total number of 80 sample was obtained during the winter of 2010. After preparation and chemical digestion of fish samples, the amounts of heavy metals were determined by spectrophotometer method. According to the results, the overall lead concentration in different organs of the two species was more than mercury and cadmium concentrations. Furthermore, the accumulation of heavy elements in gills was estimated higher than the other organs. Although a significant difference (P

  9. Degree of coupling in high-rise mixed shear walls structures

    Indian Academy of Sciences (India)

    A simple method of analysis is presented to determine the influence of single shear walls (SSW) on the degree of coupling DoC and on the peak shear demand PSD for beams of coupled shear walls (CSW) in mixed shear wall structures (MSW). Non-coupled lateral load resisting structures such as singular planar walls and ...

  10. Shear weakening for different lithologies observed at different saturation stages

    Science.gov (United States)

    Diethart-Jauk, Elisabeth; Gegenhuber, Nina

    2018-01-01

    For this study, samples from different lithologies ("Leitha"-limestone, "Dachstein"-limestone, "Haupt"-dolomite, "Bunt"-sandstone, Grey Berea sandstone, granite, quartzite and basalt) were selected. Samples were dried at 70 °C, respectively 105 °C and were saturated with brine. Mass, porosity, permeability, compressional and shear wave velocity were determined from dry and brine saturated samples at laboratory conditions, based on an individual measurement program. Shear modulus was calculated to find out, if shear weakening exists for the dataset. Shear weakening means that shear modulus of dry samples is higher than of saturated samples, but it is assumed that shear modulus is unaffected by saturation. "Dachstein"-limestone and basalt show shear weakening, quartzite samples show both weakening and hardening. Granite samples are affected by temperature, after drying with 105 °C no change can be observed anymore. "Bunt"-sandstone samples show a change in the shear modulus in a small extent, although they may contain clay minerals. The other lithologies show no effect. Explanations for carbonate samples can be the complicated pore structure, for basalt it could be that weathering creates clay minerals which are known as causes for a change of the shear modulus. Fluid viscosity can also be an important factor.

  11. SHEAR ACCELERATION IN EXPANDING FLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Rieger, F. M. [ZAH, Institut für Theoretische Astrophysik, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany); Duffy, P., E-mail: frank.rieger@mpi-hd.mpg.de, E-mail: peter.duffy@ucd.ie [University College Dublin, Belfield, Dublin 4 (Ireland)

    2016-12-10

    Shear flows are naturally expected to occur in astrophysical environments and potential sites of continuous non-thermal Fermi-type particle acceleration. Here we investigate the efficiency of expanding relativistic outflows to facilitate the acceleration of energetic charged particles to higher energies. To this end, the gradual shear acceleration coefficient is derived based on an analytical treatment. The results are applied to the context of the relativistic jets from active galactic nuclei. The inferred acceleration timescale is investigated for a variety of conical flow profiles (i.e., power law, Gaussian, Fermi–Dirac) and compared to the relevant radiative and non-radiative loss timescales. The results exemplify that relativistic shear flows are capable of boosting cosmic-rays to extreme energies. Efficient electron acceleration, on the other hand, requires weak magnetic fields and may thus be accompanied by a delayed onset of particle energization and affect the overall jet appearance (e.g., core, ridge line, and limb-brightening).

  12. Focus: Nucleation kinetics of shear bands in metallic glass.

    Science.gov (United States)

    Wang, J Q; Perepezko, J H

    2016-12-07

    The development of shear bands is recognized as the primary mechanism in controlling the plastic deformability of metallic glasses. However, the kinetics of the nucleation of shear bands has received limited attention. The nucleation of shear bands in metallic glasses (MG) can be investigated using a nanoindentation method to monitor the development of the first pop-in event that is a signature of shear band nucleation. The analysis of a statistically significant number of first pop-in events demonstrates the stochastic behavior that is characteristic of nucleation and reveals a multimodal behavior associated with local spatial heterogeneities. The shear band nucleation rate of the two nucleation modes and the associated activation energy, activation volume, and site density were determined by loading rate experiments. The nucleation activation energy is very close to the value that is characteristic of the β relaxation in metallic glass. The identification of the rate controlling kinetics for shear band nucleation offers guidance for promoting plastic flow in metallic glass.

  13. Investigation of sheared liquids by neutron backscattering and reflectivity

    CERN Document Server

    Wolff, M; Hock, R; Frick, B; Zabel, H

    2002-01-01

    We have investigated by neutron scattering structural and dynamical properties of water solutions of the triblock copolymer P85 under shear. To this end a shear cell that suits the requirements for neutron backscattering and another for reflectivity experiments have been built. In reflectivity measurements we find the polymer concentration (nominal concentration of 33% by weight) to vary right at the surface between 12% and 52% for hydrophilic or hydrophobic coated silicon wavers, for temperatures between 18 C and 73 C and for shear rates up to 2500 s sup - sup 1. Additional structural changes deeper in the bulk are also observed. On the backscattering instrument (IN10 at ILL) we find that the liquid appears to stick to the plates of the shear cell, implying an unusual macroscopic velocity distribution that differs from that found earlier for lubrication oils. We report further on changes of the quasielastic line width in the direction of the shear gradient for different temperatures and shear rates. (orig.)

  14. Shear transfer capacity of reinforced concrete exposed to fire

    Science.gov (United States)

    Ahmad, Subhan; Bhargava, Pradeep; Chourasia, Ajay

    2018-04-01

    Shear transfer capacity of reinforced concrete elements is a function of concrete compressive strength and reinforcement yield strength. Exposure of concrete and steel to elevated temperature reduces their mechanical properties resulting in reduced shear transfer capacity of RC elements. The objective of present study is to find the effect of elevated temperature on shear transfer capacity of reinforced concrete. For this purpose pushoff specimens were casted using normal strength concrete. After curing, specimens were heated to 250°C and 500°C in an electric furnace. Cooled specimens were tested for shear transfer capacity in a universal testing machine. It was found that shear transfer capacity and stiffness (slope of load-slip curve) were reduced when the specimens were heated to 250°C and 500°C. Load level for the initiation of crack slip was found to be decreased as the temperature was increased. A simple analytical approach is also proposed to predict the shear transfer capacity of reinforced concrete after elevated temperature.

  15. Experimental Research on Boundary Shear Stress in Typical Meandering Channel

    Science.gov (United States)

    Chen, Kai-hua; Xia, Yun-feng; Zhang, Shi-zhao; Wen, Yun-cheng; Xu, Hua

    2018-06-01

    A novel instrument named Micro-Electro-Mechanical System (MEMS) flexible hot-film shear stress sensor was used to study the boundary shear stress distribution in the generalized natural meandering open channel, and the mean sidewall shear stress distribution along the meandering channel, and the lateral boundary shear stress distribution in the typical cross-section of the meandering channel was analysed. Based on the measurement of the boundary shear stress, a semi-empirical semi-theoretical computing approach of the boundary shear stress was derived including the effects of the secondary flow, sidewall roughness factor, eddy viscosity and the additional Reynolds stress, and more importantly, for the first time, it combined the effects of the cross-section central angle and the Reynolds number into the expressions. Afterwards, a comparison between the previous research and this study was developed. Following the result, we found that the semi-empirical semi-theoretical boundary shear stress distribution algorithm can predict the boundary shear stress distribution precisely. Finally, a single factor analysis was conducted on the relationship between the average sidewall shear stress on the convex and concave bank and the flow rate, water depth, slope ratio, or the cross-section central angle of the open channel bend. The functional relationship with each of the above factors was established, and then the distance from the location of the extreme sidewall shear stress to the bottom of the open channel was deduced based on the statistical theory.

  16. Shear-Induced Membrane Fusion in Viscous Solutions

    KAUST Repository

    Kogan, Maxim; Feng, Bobo; Nordé n, Bengt; Rocha, Sandra; Beke-Somfai, Tamá s

    2014-01-01

    Large unilamellar lipid vesicles do not normally fuse under fluid shear stress. They might deform and open pores to relax the tension to which they are exposed, but membrane fusion occurring solely due to shear stress has not yet been reported. We

  17. Evaluating interfacial shear stresses in composite hollo

    Directory of Open Access Journals (Sweden)

    Aiham Adawi

    2016-09-01

    Full Text Available Analytical evaluation of the interfacial shear stresses for composite hollowcore slabs with concrete topping is rare in the literature. Adawi et al. (2014 estimated the interfacial shear stiffness coefficient (ks that governs the behavior of the interface between hollowcore slabs and the concrete topping using push-off tests. This parameter is utilized in this paper to provide closed form solutions for the differential equations governing the behavior of simply supported composite hollowcore slabs. An analytical solution based on the deformation compatibility of the composite section and elastic beam theory, is developed to evaluate the shear stresses along the interface. Linear finite element modeling of the full-scale tests presented in Adawi et al. (2015 is also conducted to validate the developed analytical solution. The proposed analytical solution was found to be adequate in estimating the magnitude of horizontal shear stress in the studied composite hollowcore slabs.

  18. Shear crack formation and propagation in fiber reinforced cementitious composites (FRCC)

    DEFF Research Database (Denmark)

    Paegle, Ieva; Fischer, Gregor

    2011-01-01

    Knowledge of the mechanisms controlling crack formation, propagation and failure of FRCC under shear loading is currently limited. This paper presents a study that utilized photogrammetry to monitor the shear deformations of two FRCC materials and ordinary concrete (OC). Multiple shear cracks...... and strain hardening of both FRCC materials was observed under shear loading. The influence of fibers, fiber type, including polyvinyl alcohol (PVA) and polypropylene (PP) fibers, and shear crack angle were investigated. Based upon photogrammetric results, fundamental descriptions of shear crack opening...

  19. Shear crack formation and propagation in fiber reinforced cementitious composites (FRCC)

    DEFF Research Database (Denmark)

    Paegle, Ieva; Fischer, Gregor

    2012-01-01

    Knowledge of the mechanisms controlling crack formation, propagation and failure of FRCC under shear loading is currently limited. This paper presents a study that utilized photogrammetry to monitor the shear deformations of two FRCC materials and ordinary concrete (OC). Multiple shear cracks...... and strain hardening of both FRCC materials was observed under shear loading. The influence of fibers, fiber type, including polyvinyl alcohol (PVA) and polypropylene (PP) fibers, and shear crack angle were investigated. Based upon photogrammetric results, fundamental descriptions of shear crack opening...

  20. Undrained shear strength determination and correlations on Søvind Marl

    DEFF Research Database (Denmark)

    Grønbech, Gitte Lyng; Nielsen, Benjaminn Nordahl

    2016-01-01

    on both the preconsolidation and the undrained shear strength. Two apparent values of the preconsolidation stresses can be determined due to the fissured structure (Grønbech et al. 2015) which also considerably decreases the undrained shear strength. Determination of shear strength of fissured clay...... is done through field testing or triaxial testing. Christensen and Hansen (1959) tested fissured Danish Oligocene clay and found the undrained shear strength, Su, be approximately 1/3 of the measured field vane shear strength, cfv. This correlation has since been used in Danish geotechnical practice...

  1. Diagonal Cracking and Shear Strength of Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Zhang, Jin-Ping

    1997-01-01

    The shear failure of non-shear-reinforced concrete beams with normal shear span ratios is observed to be governed in general by the formation of a critical diagonal crack. Under the hypothesis that the cracking of concrete introduces potential yield lines which may be more dangerous than the ones...

  2. High shear microfluidics and its application in rheological measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kai; Lee, L.James; Koelling, Kurt W. [The Ohio State University, Department of Chemical Engineering, Columbus, OH (United States)

    2005-02-01

    High shear rheology was explored experimentally in microchannels (150 x 150 {mu}m). Two aqueous polymer solutions, polyethylene oxide (viscoelastic fluid) and hydroxyethyl cellulose (viscous fluid) were tested. Bagley correction was applied to remove the end effect. Wall slip was investigated with Mooney's analysis. Shear rates as high as 10{sup 6} s {sup -1} were obtained in the pressure-driven microchannel flow, allowing a smooth extension of the low shear rheological data obtained from the conventional rheometers. At high shear rates, polymer degradation was observed for PEO solutions at a critical microchannel wall shear stress of 4.1 x 10 {sup 3} Pa. Stresses at the ends of the microchannel also contributed to PEO degradation significantly. (orig.)

  3. Combined shearing interferometer and hartmann wavefront sensor

    International Nuclear Information System (INIS)

    Hutchin, R. A.

    1985-01-01

    A sensitive wavefront sensor combining attributes of both a Hartmann type of wavefront sensor and an AC shearing interferometer type of wavefront sensor. An incident wavefront, the slope of which is to be detected, is focussed to first and second focal points at which first and second diffraction gratings are positioned to shear and modulate the wavefront, which then diverges therefrom. The diffraction patterns of the first and second gratings are positioned substantially orthogonal to each other to shear the wavefront in two directions to produce two dimensional wavefront slope data for the AC shearing interferometer portion of the wavefront sensor. First and second dividing optical systems are positioned in the two diverging wavefronts to divide the sheared wavefront into an array of subapertures and also to focus the wavefront in each subaperture to a focal point. A quadrant detector is provided for each subaperture to detect the position of the focal point therein, which provides a first indication, in the manner of a Hartmann wavefront sensor, of the local wavefront slope in each subaperture. The total radiation in each subaperture, as modulated by the diffraction grating, is also detected by the quadrant detector which produces a modulated output signal representative thereof, the phase of which relative to modulation by the diffraction grating provides a second indication of the local wavefront slope in each subaperture, in the manner of an AC shearing interferometer wavefront sensor. The data from both types of sensors is then combined by long term averaging thereof to provide an extremely sensitive wavefront sensor

  4. Starch-zein beldns formed by shear flow

    NARCIS (Netherlands)

    Habeych Narvaez, E.A.; Dekkers, B.; Goot, van der A.J.; Boom, R.M.

    2008-01-01

    A newly in-house developed shearing device was used to explore the formation of new types of microstructures in concentrated starch¿zein blends. The device allowed processing of the biopolymer blends under homogeneous, simple shear flow conditions. Water and glycerol were added as plasticizers.

  5. The theoretical shear strength of fcc crystals under superimposed triaxial stress

    Energy Technology Data Exchange (ETDEWEB)

    Cerny, M., E-mail: cerny.m@fme.vutbr.cz [Institute of Engineering Physics, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2, CZ-616 69 Brno (Czech Republic); Pokluda, J. [Institute of Engineering Physics, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2, CZ-616 69 Brno (Czech Republic)

    2010-05-15

    The influence of a triaxial stress applied normally to shear planes and shear direction during affine shear deformation of face-centered cubic crystals on the theoretical shear strength is studied for the <112-bar >{l_brace}111{r_brace} shear system using first-principles methods. The applied relaxation procedure guarantees that the modeled system is subjected to a superposition of shear, normal and in-plane stresses with individually adjustable in-plane and normal stress values. The theoretical shear strengths of individual elements prove to be qualitatively different functions of the superimposed stresses. In the special case of hydrostatic loading, however, these functions are qualitatively uniform. This behavior is discussed in terms of the electronic structure.

  6. Ballooning mode stabilization by moderate sheared rotation

    International Nuclear Information System (INIS)

    Hameiri, E.

    1996-01-01

    Sheared toroidal plasma rotation has been known for some time to have a stabilizing effect on the ballooning modes. A recent calculation showed that a large flow shear, with dΩ/dq of the order of the Alfven toroidal frequency, can stabilize the ballooning modes. This latest result is, in fact, not so optimistic. For observed flows with Mach number of order unity one gets dΩ/dq smaller by a factor O(√β) from the required level (if the flow shear length is of the same order as the magnetic shear length). Moreover, the calculation does not take into account a possibly large transient growth of the mode amplitude due to its Floquet structures We show here that, in fact, there is a general tendency of the ballooning mode to stabilize as soon as the flow shear dΩ/dq exceeds the (O√β smaller) open-quotes slowclose quotes magnetosonic wave frequency. Our analysis is perturbative, where the small parameter is related to the small coupling between the slow and Alfven waves-as is the case in a high aspect-ratio tokamak. (In the perturbation it is important to take the Hamiltonian nature of the governing equations into account.) Moreover, our results apply to the relevant transient growth of the mode amplitude

  7. Shear behavior of concrete beams externally prestressed with Parafil ropes

    Directory of Open Access Journals (Sweden)

    A.H. Ghallab

    2013-03-01

    Full Text Available Although extensive work has been carried out investigating the use of external prestressing system for flexural strengthening, a few studies regarding the shear behavior of externally prestressed beams can be found. Five beams, four of them were externally strengthened using Parafil rope, were loaded up to failure to investigate the effect of shear span/depth ratio, external prestressing force and concrete strength on their shear behavior. Test results showed that the shear span to depth ratio has a significant effect on both the shear strength and failure mode of the strengthened beams and the presence of external prestressing force increased the ultimate load of the tested beams by about 75%. Equations proposed by different codes for both the conventional reinforced concrete beams and for ordinary prestressed beams were used to evaluate the obtained experimental results. In general, codes equations showed a high level of conservatism in predicting the shear strength of the beams. Also, using the full strength rather than half of the concrete shear strength in the Egyptian code PC-method improves the accuracy of the calculated ultimate shear strength.

  8. Shear strength of palm oil clinker concrete beams

    International Nuclear Information System (INIS)

    Mohammed, Bashar S.; Foo, W.L.; Hossain, K.M.A.; Abdullahi, M.

    2013-01-01

    Highlights: ► Palm oil clinker can be used as lightweight aggregate for the production of structural concrete. ► The palm oil clinker concrete can be classified as lightweight concrete. ► Full scale reinforced palm oil clinker concrete beams without shear reinforcement were tested. ► The CSA based design equation can be used for the prediction of shear capacity with a limit. - Abstract: This paper presents experimental results on the shear behavior of reinforced concrete beams made of palm oil clinker concrete (POCC). Palm oil clinker (POC) is a by-product of palm oil industry and its utilization in concrete production not only solves the problem of disposing this solid waste but also helps to conserve natural resources. Seven reinforced POCC beams without shear reinforcement were fabricated and their shear behavior was tested. POCC has been classified as a lightweight structural concrete with air dry density less than 1850 kg/m 3 and a 28-day compressive strength more than 20 MPa. The experimental variables which have been considered in this study were the POCC compressive strength, shear span–depth ratio (a/d) and the ratio of tensile reinforcement (ρ). The results show that the failure mode of the reinforced POCC beam is similar to that of conventional reinforced concrete beam. In addition, the shear equation of the Canadian Standard Association (CSA) can be used in designing reinforced POCC beam with ρ ⩾ 1. However, a 0.5 safety factor should be included in the formula for ρ < 1

  9. Introduction to the viewpoint set on shear bands

    International Nuclear Information System (INIS)

    Hutchinson, J.W.

    1984-01-01

    Recent work aimed at improving our understanding of shear banding and flow localization as modes of deformation and failure is summarized in the six viewpoint articles which follow. For the most part, the emphasis here is on the observation and analysis of shear banding in metals, but active efforts are also underway to understand the role of shear bands in the deformation and failure of soils and rocks. There is a tendency to regard shear bands as a failure mode, as indeed they often are. But extensive straining under highly constrained conditions such as rolling can give rise to profuse flow localization into shear bands which can be regarded as microscopic in the sense that their extent is on the scale of the grains rather than the overall dimensions of the block of material being deformed. Hatherly and Malin describe in detail the observation of such bands and emphasize that they should be considered as a mode of deformation under these circumstances. They relate the formation of the bands to microstructural aspects and discuss their role in the development of recrystallization textures. It will be clear from reading the articles in this viewpoint set that the beginnings of a quantitative theory of shear banding is in place. Continued progress will require parallel developments in constitutive theory and experimental observation. Moreover, basic questions remain to be explored related to the spatial development of the shear bands, their mutual interaction, their development into a failure mode, and how these are influenced by factors such as overall deformational constraint, rate of straining, and temperature

  10. Shear behavior of reinforced Engineered Cementitious Composites (ECC) beams

    DEFF Research Database (Denmark)

    Paegle, Ieva; Fischer, Gregor

    2010-01-01

    This paper describes an experimental investigation of the shear behavior of beams consisting of steel reinforced Engineered Cementitious Composites (ECC). Based on the strain hardening and multiple cracking behavior of ECC, this study investigates the extent to which ECC can improve the shear...... capacity of beams loaded primarily in shear and if ECC can partially or fully replace the conventional transverse steel reinforcement in beams. However, there is a lack of understanding of how the fibers affect the shear carrying capacity and deformation behavior of structural members if used either...

  11. Improvement of shearing machine in the Tokai Reprocessing Plant

    International Nuclear Information System (INIS)

    Takae, Akiyoshi; Otani, Yoshikuni

    1994-01-01

    The shearing machine in the Tokai Reprocessing Plant has been improved and refurbished through its operational experience for about 20 years. Every component except the shear housing and magazine is changed for improved things by PNC, while the shearing machine had been designed and fabricated originally by a French Company. The improvement of the shearing machine was carried out for the purpose of settling the problems which were experienced in the past operation, and improving durability, remote maintainability, and operability. The details of their improvement work are described. (author)

  12. Gelation under shear

    Energy Technology Data Exchange (ETDEWEB)

    Butler, B.D.; Hanley, H.J.M.; Straty, G.C. [National Institute of Standards and Technology, Boulder, CO (United States); Muzny, C.D. [Univ. of Colorado, Boulder, CO (United States)

    1995-12-31

    An experimental small angle neutron scattering (SANS) study of dense silica gels, prepared from suspensions of 24 nm colloidal silica particles at several volume fractions {theta} is discussed. Provided that {theta}{approx_lt}0.18, the scattered intensity at small wave vectors q increases as the gelation proceeds, and the structure factor S(q, t {yields} {infinity}) of the gel exhibits apparent power law behavior. Power law behavior is also observed, even for samples with {theta}>0.18, when the gel is formed under an applied shear. Shear also enhances the diffraction maximum corresponding to the inter-particle contact distance of the gel. Difficulties encountered when trying to interpret SANS data from these dense systems are outlined. Results of computer simulations intended to mimic gel formation, including computations of S(q, t), are discussed. Comments on a method to extract a fractal dimension characterizing the gel are included.

  13. Freezing of a colloidal liquid subject to shear flow

    International Nuclear Information System (INIS)

    Bagchi, B.; Thirumalai, D.

    1988-01-01

    A nonequilibrium generalization of the density-functional theory of freezing is proposed to investigate the shear-induced first-order phase transition in colloidal suspensions. It is assumed that the main effect of a steady shear is to break the symmetry of the structure factor of the liquid and that for small shear rate, the phenomenon of a shear-induced order-disorder transition may be viewed as an equilibrium phase transition. The theory predicts that the effective density at which freezing takes place increases with shear rate. The solid (which is assumed to be a bcc lattice) formed upon freezing is distorted and specifically there is less order in one plane compared with the order in the other two perpendicular planes. It is shown that there exists a critical shear rate above which the colloidal liquid does not undergo a transition to an ordered (or partially ordered) state no matter how large the density is. Conversely, above the critical shear rate an initially formed bcc solid always melts into an amorphous or liquidlike state. Several of these predictions are in qualitative agreement with the light-scattering experiments of Ackerson and Clark. The limitations as well as possible extensions of the theory are also discussed

  14. Evaluation of size dependent design shear strength of reinforced ...

    Indian Academy of Sciences (India)

    to the development of the size dependent models on the shear strength in ... predict the diagonal cracking strength and the ultimate shear strength of RC ... ing strength of normal beams was by Zsutty (1968) based on the data base available without .... The comparison of the calculated shear strength of the beams is shown.

  15. Shear capacity of ASR damaged structures – in-depth analysis of some in-situ shear tests on bridge slabs

    DEFF Research Database (Denmark)

    Hansen, Søren Gustenhoff; Barbosa, Ricardo Antonio; Hoang, Linh Cao

    2016-01-01

    This paper deals with the influence of alkali-silica reaction (ASR) on the shear capacity for concrete slabs without shear reinforcement. An experimental full-scale in-situ program consisting of four slabs from a bridge (Vosnæsvej) has been carried out and the results have been published in ref. [1......] with the principal author of this paper as co-author. After the experiments, a detailed measurement of the test specimens was conducted. Based on these measurements a thorough analysis of the experimental results was carried out and evaluated by a plastic model for shear capacity, Crack Sliding Model (CSM...

  16. Shear-wave dynamic behavior using two different orientations

    International Nuclear Information System (INIS)

    Ghassem Alaskari, M. K.; Hashemi, S. J.

    2007-01-01

    For laterally complex media, it may be more suitable to take a different orientation of the displacement vector of Shear-waves. This may change the sign of several imaginary reflections and conversion coefficients to be used in reservoir characterization and Amplitude Versus Offset analysis or modeling. In this new convention the positive direction of the displacement vector of reflected Shear-waves is chosen to the left of ray tangent (in the direction of wave propagation). Therefore, the definition of the displacement vector of shear-waves can be used properly even for very complicated media. Finally the shear-wave dynamic behavior of a reservoir zone can be illustrated for laterally varying structures in terms of the amplitude variation and phase behavior using this new orientation

  17. Mean E×B shear effect on geodesic acoustic modes in Tokamaks

    International Nuclear Information System (INIS)

    Singh, Rameswar; Gurcan, Ozgur D.

    2015-01-01

    E × B shearing effect on geodesic acoustic mode (GAM) is investigated for the first time both as an initial value problem in the shearing frame and as an eigenvalue value problem in the lab frame. The nontrivial effects are that E × B shearing couples the standard GAM perturbations to their complimentary poloidal parities. The resulting GAM acquires an effective inertia increasing in time leading to GAM damping. Eigenmode analysis shows that GAMs are radially localized by E × B shearing with the mode width being inversely proportional and radial wave number directly proportional to the shearing rate for weak shear. (author)

  18. Dilatancy induced ductile-brittle transition of shear band in metallic glasses

    Science.gov (United States)

    Zeng, F.; Jiang, M. Q.; Dai, L. H.

    2018-04-01

    Dilatancy-generated structural disordering, an inherent feature of metallic glasses (MGs), has been widely accepted as the physical mechanism for the primary origin and structural evolution of shear banding, as well as the resultant shear failure. However, it remains a great challenge to determine, to what degree of dilatation, a shear banding will evolve into a runaway shear failure. In this work, using in situ acoustic emission monitoring, we probe the dilatancy evolution at the different stages of individual shear band in MGs that underwent severely plastic deformation by the controlled cutting technology. A scaling law is revealed that the dilatancy in a shear band is linearly related to its evolution degree. A transition from ductile-to-brittle shear bands is observed, where the formers dominate stable serrated flow, and the latter lead to a runaway instability (catastrophe failure) of serrated flow. To uncover the underlying mechanics, we develop a theoretical model of shear-band evolution dynamics taking into account an atomic-scale deformation process. Our theoretical results agree with the experimental observations, and demonstrate that the atomic-scale volume expansion arises from an intrinsic shear-band evolution dynamics. Importantly, the onset of the ductile-brittle transition of shear banding is controlled by a critical dilatation.

  19. The response of dense dry granular material to the shear reversal

    Science.gov (United States)

    Zhang, Jie; Ren, Jie; Farhadi, Somayeh; Behringer, Robert

    2008-11-01

    We have performed two dimensional granular experiments under pure shear using bidisperse photo-elastic disks. Starting from a stress free state, a square box filled with granular particles is subject to shear. The forward shears involved various number of steps, leading to maximum strains between 0.1 and 0.3. The area is kept constant during the shear. The network of force chains gradually built up as the strain increased, leading to increased pressure and shear stress. Reverse shear was then applied to the system. Depending on the initial packing fraction and the strain at which the shear is reversed, the force chain network built prior to the shear reversal may be destroyed completely or partially destroyed. Following the force chain weakening, when the reserve shear is continuously applied to the system, there is a force chain strengthening. Following each change of the system, contact forces of individual disks were measured by applying an inverse algorithm. We also kept track of the displacement and angle of rotation of every particle from frame to frame. We present the results for the structure failure and reconstruction during shear reversals. We also present data for stresses, contact force distributions and other statistical measures.

  20. Shear-stress fluctuations and relaxation in polymer glasses

    Science.gov (United States)

    Kriuchevskyi, I.; Wittmer, J. P.; Meyer, H.; Benzerara, O.; Baschnagel, J.

    2018-01-01

    We investigate by means of molecular dynamics simulation a coarse-grained polymer glass model focusing on (quasistatic and dynamical) shear-stress fluctuations as a function of temperature T and sampling time Δ t . The linear response is characterized using (ensemble-averaged) expectation values of the contributions (time averaged for each shear plane) to the stress-fluctuation relation μsf for the shear modulus and the shear-stress relaxation modulus G (t ) . Using 100 independent configurations, we pay attention to the respective standard deviations. While the ensemble-averaged modulus μsf(T ) decreases continuously with increasing T for all Δ t sampled, its standard deviation δ μsf(T ) is nonmonotonic with a striking peak at the glass transition. The question of whether the shear modulus is continuous or has a jump singularity at the glass transition is thus ill posed. Confirming the effective time-translational invariance of our systems, the Δ t dependence of μsf and related quantities can be understood using a weighted integral over G (t ) .

  1. Line Crack Subject to Antiplane Shear.

    Science.gov (United States)

    1978-07-01

    shear is obtained for the initiation of fracture. If the concept of the surface tension is usedone is able to calculate the cohesive stress for brittle ...Expression of the Griffith -racture criterion for brittle fracture. We have arrived at this result via the maximum shear-stress hypothesis, rather than...Crescent Beach Road, Glen Cove Prof. G.S. Heller Long Island, New York 11542 Division of Engineering Brown University Prof. Daniel

  2. Supersonic shear imaging provides a reliable measurement of resting muscle shear elastic modulus

    International Nuclear Information System (INIS)

    Lacourpaille, Lilian; Hug, François; Bouillard, Killian; Nordez, Antoine; Hogrel, Jean-Yves

    2012-01-01

    The aim of the present study was to assess the reliability of shear elastic modulus measurements performed using supersonic shear imaging (SSI) in nine resting muscles (i.e. gastrocnemius medialis, tibialis anterior, vastus lateralis, rectus femoris, triceps brachii, biceps brachii, brachioradialis, adductor pollicis obliquus and abductor digiti minimi) of different architectures and typologies. Thirty healthy subjects were randomly assigned to the intra-session reliability (n = 20), inter-day reliability (n = 21) and the inter-observer reliability (n = 16) experiments. Muscle shear elastic modulus ranged from 2.99 (gastrocnemius medialis) to 4.50 kPa (adductor digiti minimi and tibialis anterior). On the whole, very good reliability was observed, with a coefficient of variation (CV) ranging from 4.6% to 8%, except for the inter-operator reliability of adductor pollicis obliquus (CV = 11.5%). The intraclass correlation coefficients were good (0.871 ± 0.045 for the intra-session reliability, 0.815 ± 0.065 for the inter-day reliability and 0.709 ± 0.141 for the inter-observer reliability). Both the reliability and the ease of use of SSI make it a potentially interesting technique that would be of benefit to fundamental, applied and clinical research projects that need an accurate assessment of muscle mechanical properties. (note)

  3. Constitutive Behavior of Reinforced Concrete Membrane Elements under Tri-directional Shear

    Science.gov (United States)

    Labib, Moheb

    The two-dimensional behavior of typical reinforced concrete (RC) structures has been extensively studied in the past several decades by investigating the constitutive behavior of full-scale reinforced concrete elements subjected to a bi-axial state of stress. In order to understand the true behavior of many large complex structures, the goal of this investigation is to develop new constitutive relationships for RC elements subjected to tri-directional shear stresses. Recently, additional out-of-plane jacks were installed on the panel tester at University of Houston so that concrete elements could be subjected to tri-directional shear stresses. This upgrade makes the panel tester the only one of its kind in the US that is capable of applying such combinations of stresses on full-scale reinforced concrete elements. This dissertation presents the details of the mounting and installation of the additional hydraulic jacks on the universal panel tester. The experimental program includes a series of seven reinforced concrete elements subjected to different combinations of in-plane and out-of-plane shear stresses. Increasing the applied out-of-plane shear stresses reduced the membrane shear strength of the elements. The effect of applying out-of-plane shear stresses on the in-plane shear strength was represented by modifying the softening coefficient in the compression stress strain curve of concrete struts. The modified model was able to capture the behavior and the ultimate capacity of the tested elements. The effect of the in-plane shear reinforcement ratio on the interaction between in-plane and out-of-plane shear stresses was evaluated. The model was implemented in the Finite Element package FEAP and was used to predict the ultimate capacity of many structures subjected to a combination of in-plane and out-of-plane shear stresses. The results of the analytical model were used to develop simplified design equations for members subjected to bi-directional shear loads

  4. Temperature-dependent residual shear strength characteristics of smectite-rich landslide soils

    Science.gov (United States)

    Shibasaki, Tatsuya; Matsuura, Sumio; Okamoto, Takashi

    2015-04-01

    On gentle clayey slopes in weathered argillaceous rock areas, there exist many landslides which repeatedly reactivate with slow movement. The slip surface soils of these landslides are sometimes composed dominantly of swelling clay mineral (smectite) which is well known to show extremely low residual friction angle. From field data monitored at landslide sites in Japan, it has become clear that some landslides with relatively shallow slip surface begin to move and become active in late autumn or early winter every year. In such cases, the triggering mechanisms of landslides have not been understood well enough, because landslide initiation and movement are not always clearly linked with rises in pore water pressures (ground water levels). In this study, we focus on the influence of seasonal variation in ground temperature on slope stability and have investigated the effect of temperature on the shear strength of slip surface soils. Undisturbed soil samples were collected by boring from the Busuno landslide in Japan. We performed box shear experiments on undisturbed slip surface soils at low temperature ranges (approximately 5-25 °C). XRD analysis revealed that these soils contain high fraction of smectite. Slickensided slip surface within test specimen was coincided with the shearing plane of the shear box and shear displacement was applied precisely along the localized slip surface. Experiments were performed under slow shearing rate condition (0.005mm/min) and the results showed that shear strength decreased with decreasing temperature. Temperature effect was rather significant on frictional angle than on cohesion. Ring shear experiments were also performed on normally-consolidated remoulded samples. Under residual strength condition, temperature-change experiments (cooling-event tests) ranging approximately from 5 to 25 °C were performed on smectite-rich landslide soils and commercial bentonites. As well as the results by box shear test, shear weakening

  5. Shear viscosity of liquid mixtures: Mass dependence

    International Nuclear Information System (INIS)

    Kaushal, Rohan; Tankeshwar, K.

    2002-06-01

    Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model. (author)

  6. Shear viscosity of liquid mixtures Mass dependence

    CERN Document Server

    Kaushal, R

    2002-01-01

    Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model.

  7. Transport reduction via shear flow modification of the cross phase

    International Nuclear Information System (INIS)

    Ware, A.S.; Terry, P.W.; Diamond, P.H.; Carreras, B.A.

    1996-01-01

    As a model example of the effect of E x B shear flow on the cross phase between electrostatic potential and pressure fluctuations, a nonlinear theory of resistive pressure gradient driven turbulence (RPGDT) in a shear flow is presented. This work builds on numerical studies of RPGDT, which have shown that both flow shear and curvature can affect the cross phase as well as the fluctuation levels. In this work, we show that the effect of shear flow on transport can be expressed through the temporal response of pressure to potential. It is shown heuristically that even in the case where the fluctuation levels are not modified, the flow shear still acts to reduce the phase angle between potential and pressure fluctuations, thereby suppressing transport. The scaling of the cross phase with flow shear and flow curvature is presented. (author)

  8. Energies and media nr 31. The EPR. Its role in the nuclear sector. Finland, Flamanville, Abu Dhabi. The reactor range

    International Nuclear Information System (INIS)

    2010-02-01

    After some comments on recent events in the nuclear sector in different countries (energy policy and projects in the USA, China, Italy, UK, Germany), this publication discusses the role of the EPR. It briefly outlines the characteristics of the third generation reactors compared with that of the first and second ones, evokes the influence of September 11 on design specifications, and evokes the international discussions about the project of fourth-generation reactors and the researches on nuclear fusion. It outlines the current context and the role of nuclear energy in the reduction of greenhouse gas emissions, briefly describes the opportunities offered by the use of thorium, and by fast neutron reactors. It comments the construction of the EPRs in Finland and in Flamanville, some characteristics of the EPR control system, and how France failed in selling the EPR to Abu Dhabi. It finally evokes the French offer in terms of nuclear reactors

  9. Haptic Edge Detection Through Shear

    Science.gov (United States)

    Platkiewicz, Jonathan; Lipson, Hod; Hayward, Vincent

    2016-03-01

    Most tactile sensors are based on the assumption that touch depends on measuring pressure. However, the pressure distribution at the surface of a tactile sensor cannot be acquired directly and must be inferred from the deformation field induced by the touched object in the sensor medium. Currently, there is no consensus as to which components of strain are most informative for tactile sensing. Here, we propose that shape-related tactile information is more suitably recovered from shear strain than normal strain. Based on a contact mechanics analysis, we demonstrate that the elastic behavior of a haptic probe provides a robust edge detection mechanism when shear strain is sensed. We used a jamming-based robot gripper as a tactile sensor to empirically validate that shear strain processing gives accurate edge information that is invariant to changes in pressure, as predicted by the contact mechanics study. This result has implications for the design of effective tactile sensors as well as for the understanding of the early somatosensory processing in mammals.

  10. Piezoelectric energy harvesting through shear mode operation

    International Nuclear Information System (INIS)

    Malakooti, Mohammad H; Sodano, Henry A

    2015-01-01

    Piezoelectric materials are excellent candidates for use in energy harvesting applications due to their high electromechanical coupling properties that enable them to convert input mechanical energy into useful electric power. The electromechanical coupling coefficient of the piezoelectric material is one of the most significant parameters affecting energy conversion and is dependent on the piezoelectric mode of operation. In most piezoceramics, the d 15 piezoelectric shear coefficient is the highest coefficient compared to the commonly used axial and transverse modes that utilize the d 33 and the d 31 piezoelectric strain coefficients. However, complicated electroding methods and challenges in evaluating the performance of energy harvesting devices operating in the shear mode have slowed research in this area. The shear deformation of a piezoelectric layer can be induced in a vibrating sandwich beam with a piezoelectric core. Here, a model based on Timoshenko beam theory is developed to predict the electric power output from a cantilever piezoelectric sandwich beam under base excitations. It is shown that the energy harvester operating in the shear mode is able to generate ∼50% more power compared to the transverse mode for a numerical case study. Reduced models of both shear and transverse energy harvesters are obtained to determine the optimal load resistance in the system and perform an efficiency comparison between two models with fixed and adaptive resistances. (paper)

  11. Impedance method for measuring shear elasticity of liquids

    Science.gov (United States)

    Badmaev, B. B.; Dembelova, T. S.; Damdinov, B. B.; Gulgenov, Ch. Zh.

    2017-11-01

    Experimental results of studying low-frequency (74 kHz) shear elasticity of polymer liquids by the impedance method (analogous to the Mason method) are presented. A free-volume thick liquid layer is placed on the horizontal surface of a piezoelectric quartz crystal with dimensions 34.7 × 12 × 5.5 cm. The latter performs tangential vibrations at resonance frequency. The liquid layer experiences shear strain, and shear waves should propagate in it. From the theory of the method, it follows that, with an increase in the layer thickness, both real and imaginary resonance frequency shifts should exhibit damped oscillations and tend to limiting values. For the liquids under study, the imaginary frequency shift far exceeds the real one, which testifies to the presence of bulk shear elasticity.

  12. Local particle flux reversal under strongly sheared flow

    International Nuclear Information System (INIS)

    Terry, P.W.; Newman, D.E.; Ware, A.S.

    2003-01-01

    The advection of electron density by turbulent ExB flow with linearly varying mean yields a particle flux that can reverse sign at certain locations along the direction of magnetic shear. The effect, calculated for strong flow shear, resides in the density-potential cross phase. It is produced by the interplay between the inhomogeneities of magnetic shear and flow shear, but subject to a variety of conditions and constraints. The regions of reversed flux tend to wash out if the turbulence consists of closely spaced modes of different helicities, but survive if modes of a single helicity are relatively isolated. The reversed flux becomes negligible if the electron density response is governed by electron scales while the eigenmode is governed by ion scales. The relationship of these results to experimentally observe flux reversals is discussed

  13. Geomorphology of Dra Abu el-Naga (Egypt): The basis of the funerary sacred landscape

    Science.gov (United States)

    Bardají, T.; Martínez-Graña, A.; Sánchez-Moral, S.; Pethen, H.; García-González, D.; Cuezva, S.; Cañaveras, J. C.; Jiménez-Higueras, A.

    2017-07-01

    A geological and geomorphological analysis has been performed in the necropolis of Dra Abu el-Naga in order to understand the role played by these two factors in the development of the sacred landscape. The investigation focuses upon two aspects of the development of the necropolis, the selection criteria for tomb location and the reconstruction of the ancient funerary landscape. Around 50 tombs were surveyed, analysing the characteristics of their host rock and classifying them according to a modified Rock Mass Rating Index, in order to understand how rock quality affected tomb construction. This analysis resulted in the definition of five rock-quality classes (I to V) from very good to very poor rock. The geological study also resulted in a proposed geological-geomorphological model for the evolution of this zone of the Theban necropolis that complements previous works by other authors. Due to the lack of precise dating evidence this chronology is a relative one and is based on the chronology given by other authors for similar deposits and events. Two catastrophic events, represented by mega-landslides, have been identified, the first one predates the deposition of early Pleistocene fluvial deposits, and the second one possibly occurred during the middle-late Pleistocene. Two weathering surfaces developed under wetter than present climatic conditions and have been tentatively correlated to the mid-late Pleistocene humid period and the African-Humid Period (early-mid Holocene).

  14. Flexible Micropost Arrays for Shear Stress Measurement

    Science.gov (United States)

    Wohl, Christopher J.; Palmieri, Frank L.; Hopkins, John W.; Jackson, Allen M.; Connell, John W.; Lin, Yi; Cisotto, Alexxandra A.

    2015-01-01

    Increased fuel costs, heightened environmental protection requirements, and noise abatement continue to place drag reduction at the forefront of aerospace research priorities. Unfortunately, shortfalls still exist in the fundamental understanding of boundary-layer airflow over aerodynamic surfaces, especially regarding drag arising from skin friction. For example, there is insufficient availability of instrumentation to adequately characterize complex flows with strong pressure gradients, heat transfer, wall mass flux, three-dimensionality, separation, shock waves, and transient phenomena. One example is the acoustic liner efficacy on aircraft engine nacelle walls. Active measurement of shear stress in boundary layer airflow would enable a better understanding of how aircraft structure and flight dynamics affect skin friction. Current shear stress measurement techniques suffer from reliability, complexity, and airflow disruption, thereby compromising resultant shear stress data. The state-of-the-art for shear stress sensing uses indirect or direct measurement techniques. Indirect measurements (e.g., hot-wire, heat flux gages, oil interferometry, laser Doppler anemometry, small scale pressure drag surfaces, i.e., fences) require intricate knowledge of the studied flow, restrictive instrument arrangements, large surface areas, flow disruption, or seeding material; with smaller, higher bandwidth probes under development. Direct measurements involve strain displacement of a sensor element and require no prior knowledge of the flow. Unfortunately, conventional "floating" recessed components for direct measurements are mm to cm in size. Whispering gallery mode devices and Fiber Bragg Gratings are examples of recent additions to this type of sensor with much smaller (?m) sensor components. Direct detection techniques are often single point measurements and difficult to calibrate and implement in wind tunnel experiments. In addition, the wiring, packaging, and installation

  15. Steady shear rate rheology of suspensions, as described by the gaint floc model

    NARCIS (Netherlands)

    Stein, H.N.; Laven, J.

    2001-01-01

    The break-down of a particle network by shear is described as the development of shear planes: a region able to withstand low shear stresses may break down under a larger stress; thus with increasing shear stress and shear rate, the mutual distance (A) between successive shear planes decreases

  16. Experimental Investigation of Adiabatic Shear Banding at Different Impact Velocities

    Science.gov (United States)

    1993-01-01

    plasticity and ASB’s is the Double-notch Shear specimen, it has been decided to use this concept in shear testing at medium and high strain rates...is the Double-notch Shear specimen. it has been decided to use this concept in shear testing at medium and high strain rates. Originally, Campbell...7] C. Fressengeas, Analyse dynamique 61asto-viscoplastique de l’h6tdrogdndit6 de la ddforma- tion plastique de cisalllement, Proc. Int. Conf. on

  17. Shear-driven dynamic clusters in a colloidal glass

    Science.gov (United States)

    Eisenmann, Christoph; Kim, Chanjoong; Mattsson, Johan; Weitz, David

    2007-03-01

    We investigate the effect of shear applied to a colloidal glass on a microscopic level using a shear device that can be mounted on top of a confocal microscope. We find that the glass yields at a critical strain of about 10%, independently of the shear rate. Surprisingly, the yielding is accompanied by an increase of cooperative particle movements and a formation of dynamic clusters which is in contrast to the normal glass transition where one typically finds heterogeneity increasing whilst moving towards the glass transition.

  18. Shear viscosity of phase-separating polymer blends with viscous asymmetry

    International Nuclear Information System (INIS)

    Jeon, H. S.; Hobbie, E. K.

    2001-01-01

    Rheo-optical measurements of phase separating polymer mixtures under simple shear flow have been used to investigate the influence of domain morphology on the viscosity of emulsionlike polymer blends, in which the morphology under weak shear is droplets of one coexisting phase dispersed in a matrix of the second. The structure and viscosity of low-molecular-weight polybutadiene and polyisoprene mixtures, phase separated by quenching to a temperature inside the coexistence region of the phase diagram, were measured as a function of shear rate and composition. In the weak shear regime, the data are in qualitative agreement with an effective medium model for non-dilute suspensions of slightly deformed interacting droplets. In the strong shear regime, where a stringlike pattern appears en route to a shear-homogenized state, the data are in qualitative agreement with a simple model that accounts for viscous asymmetry in the components

  19. Keyed shear joints

    DEFF Research Database (Denmark)

    Hansen, Klaus

    This report gives a summary of the present information on the behaviour of vertical keyed shear joints in large panel structures. An attemp is made to outline the implications which this information might have on the analysis and design of a complete wall. The publications also gives a short...

  20. Study on the shear transfer of reinforced concrete at elevated temperature

    International Nuclear Information System (INIS)

    Ishida, Hiroaki; Kanazu, Tsutomu

    1989-01-01

    Reinforced concrete structures in nuclear power stations, such as a containment vessel and structural members supporting a reactor vessel, are designed assuming that they may be subjected to elevated temperature. In the design code, it is specified that the temperature of concrete must not exceed the limitation, and thermal effect shall be taken into account. In this study, the shearing test using Mattock type specimens was performed to investigate into the shear behavior of the reinforced concrete subjected to elevated temperature. The test parameters studied in this program were the reinforcement ratio in a shear plane, the compressive stress normal to a shear plane and temperature. The maximum shearing load of the specimens heated to 200 degC was about 10-20 % lower than that at normal temperature, but nearly equal to that of the specimens heated to 100 degC. The equation for evaluating the shearing strength ratio was proposed. The cracking width and slip at maximum shearing load increased as temperature rose. Up to 200 degC, the same relation existed between interface shear transfer rigidity and cracking width. (K.I.)

  1. Shear flow stabilization of the hydromagnetic Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Roderick, N.F.; Shumlak, U.; Douglas, M.; Peterkin, R.E. Jr.; Ruden, E.

    1997-01-01

    Numerical simulations have indicated that shear flow may help stabilize the hydromagnetic Rayleigh-Taylor instability in imploding plasma z-pinches. A simple extension to a model presented in Chandrasekhar has been developed to study the linear stability of incompressible plasma subjected to both a shear flow and acceleration. The model has been used to investigate the stability plasma implosion schemes using externally imposed velocity shear which develops from the plasma flow itself. Specific parameters were chosen to represent plasma implosions driven by the Saturn and PBFA-Z, pulsed power generators at Sandia National Laboratories. Results indicate a high shear is necessary to stabilize the z-pinch implosions studied

  2. Butterfly patterns in a sheared lamellar-system

    Energy Technology Data Exchange (ETDEWEB)

    Lindner, P [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France); Zipfel, J; Richtering, W [Freiburg Univ. (Germany)

    1997-04-01

    A technologically important extension of `classical` scattering techniques is to investigate soft-matter systems under non-equilibrium conditions. Shear flow is known to have a profound influence on the structure and orientation of complex fluids like thermotropic or lyotropic liquid-crystals, colloidal and polymeric solutions. There is a fundamental interest in understanding the microscopic structure and dynamics of such complex fluids as the macroscopic material properties might change with the application of an external perturbation like shear. The following example illustrates a recent study of the influence of shear on the structure of a lyotropic lamellar phase. Results using a cone-and-plate and the ILL Couette type shear-cell were obtained by rheo-small-angle light scattering (rheo-SALS) and small-angle neutron scattering (SANS) at D11. Because of the broad range of momentum transfer Q available at D11 a characteristic butterfly-pattern with a scattering peak revealing both the structure and the supramolecular structure of the system could be detected at very low Q. (author). 5 refs.

  3. Two-dimensional Shear Wave Elastography on Conventional Ultrasound Scanners with Time Aligned Sequential Tracking (TAST) and Comb-push Ultrasound Shear Elastography (CUSE)

    OpenAIRE

    Song, Pengfei; Macdonald, Michael C.; Behler, Russell H.; Lanning, Justin D.; Wang, Michael H.; Urban, Matthew W.; Manduca, Armando; Zhao, Heng; Callstrom, Matthew R.; Alizad, Azra; Greenleaf, James F.; Chen, Shigao

    2015-01-01

    Two-dimensional (2D) shear wave elastography presents 2D quantitative shear elasticity maps of tissue, which are clinically useful for both focal lesion detection and diffuse disease diagnosis. Realization of 2D shear wave elastography on conventional ultrasound scanners, however, is challenging due to the low tracking pulse-repetition-frequency (PRF) of these systems. While some clinical and research platforms support software beamforming and plane wave imaging with high PRF, the majority of...

  4. Tensile and shear methods for measuring strength of bilayer tablets.

    Science.gov (United States)

    Chang, Shao-Yu; Li, Jian-Xin; Sun, Changquan Calvin

    2017-05-15

    Both shear and tensile measurement methods have been used to quantify interfacial bonding strength of bilayer tablets. The shear method is more convenient to perform, but reproducible strength data requires careful control of the placement of tablet and contact point for shear force application. Moreover, data obtained from the shear method depend on the orientation of the bilayer tablet. Although more time-consuming to perform, the tensile method yields data that are straightforward to interpret. Thus, the tensile method is preferred in fundamental bilayer tableting research to minimize ambiguity in data interpretation. Using both shear and tensile methods, we measured the mechanical strength of bilayer tablets made of several different layer combinations of lactose and microcrystalline cellulose. We observed a good correlation between strength obtained by the tensile method and carefully conducted shear method. This suggests that the shear method may be used for routine quality test of bilayer tablets during manufacturing because of its speed and convenience, provided a protocol for careful control of the placement of the tablet interface, tablet orientation, and blade is implemented. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Stabilization of ballooning modes with sheared toroidal rotation

    International Nuclear Information System (INIS)

    Miller, R.L.; Waelbroeck, F.W.; Lao, L.L.; Taylor, T.S.

    1994-11-01

    A new code demonstrates the stabilization of MHD ballooning modes by sheared toroidal rotation. A shifted model is used to elucidate the physics and numerically reconstructed equilibria are used to analyze DIII-D discharges. In the ballooning representation, the modes shift periodically along the field line to the next point of unfavorable curvature. The shift frequency (dΩ/dq where Ω is the angular toroidal velocity and q is the safety factor) is proportional to the rotation shear and inversely proportional to the magnetic shear. Stability improves with increasing shift frequency and, in the shifted circle model, direct stable access to the second stability regime occurs when this frequency is a fraction of the Alfven frequency ω A = V A /qR. Shear stabilization is also demonstrated for an equilibrium reconstruction of a DIII-D VH-mode

  6. Research Status on Bonding Behavior of Prefabricated Concrete Shear Wall

    Science.gov (United States)

    Wang, Donghui; Liu, Xudong; Wang, Sheng; Li, Shanshan

    2018-03-01

    Prefabricated shear wall structure adapts to the development and requirements of China’s residential industrialization. The key to the prefabricated concrete shear wall structure is the connection between the prefabricated members, where the reliability of the connection of the concrete joint is related to the overall performance and seismic effect of the structure. In this paper, the microstructures of the joint surface and shear properties are analysed, and the formula for calculating the shear strength of the joint is obtained.

  7. Evaluation of Interface Shear Strength Properties of Geogrid Reinforced Foamed Recycled Glass Using a Large-Scale Direct Shear Testing Apparatus

    Directory of Open Access Journals (Sweden)

    Arul Arulrajah

    2015-01-01

    Full Text Available The interface shear strength properties of geogrid reinforced recycled foamed glass (FG were determined using a large-scale direct shear test (DST apparatus. Triaxial geogrid was used as a geogrid reinforcement. The geogrid increases the confinement of FG particles during shear; consequently the geogrid reinforced FG exhibits smaller vertical displacement and dilatancy ratio than FG at the same normal stress. The failure envelope of geogrid reinforced FG, at peak and critical states, coincides and yields a unique linear line possibly attributed to the crushing of FG particles and the rearrangement of crushed FG after peak shear state. The interface shear strength coefficient α is approximately constant at 0.9. This value can be used as the interface parameter for designing a reinforced embankment and mechanically stabilized earth (MSE wall when FG is used as a lightweight backfill and triaxial geogrid is used as an extensible earth reinforcement. This research will enable FG, recently assessed as suitable for lightweight backfills, to be used together with geogrids in a sustainable manner as a lightweight MSE wall. The geogrid carries tensile forces, while FG reduces bearing stresses imposed on the in situ soil. The use of geogrid reinforced FG is thus significant from engineering, economical, and environmental perspectives.

  8. The instantaneous shear modulus in the shoving model

    DEFF Research Database (Denmark)

    Dyre, J. C.; Wang, W. H.

    2012-01-01

    We point out that the instantaneous shear modulus G∞ of the shoving model for the non-Arrhenius temperature dependence of viscous liquids’ relaxation time is the experimentally accessible highfrequency plateau modulus, not the idealized instantaneous affine shear modulus that cannot be measured....... Data for a large selection of metallic glasses are compared to three different versions of the shoving model. The original shear-modulus based version shows a slight correlation to the Poisson ratio, which is eliminated by the energy-landscape formulation of the model in which the bulk modulus plays...

  9. Shear viscosity of liquid argon and liquid rubidium

    International Nuclear Information System (INIS)

    Chiakwelu, O.

    1978-01-01

    A direct evaluation of the shear viscosity coefficient for models of liquid rubidium and liquid argon is presented by neglecting the cross-terms in the autocorrelation function of the transverse component of the momentum stress tensor. The time dependence of the shear viscosity for liquid argon is found to display a long decaying tail in qualitative agreement with a computer calculation of Levesque et al. However, the numerical values of the shear viscosity coefficients are smaller than the experimentally determined values of about 45% for liquid rubidium and 35% for liquid argon

  10. Study of magnetorheological fluids at high shear rates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaojie; Gordaninejad, Faramarz [University of Nevada, Department of Mechanical Engineering, Reno, NV (United States)

    2006-08-15

    The tunable rheological properties of magnetorheological (MR) materials at high shear rates are studied using a piston-driven flow-mode-type rheometer. The proposed method provides measurement of the apparent viscosity and yield stress of MR fluids for a shear rate range of 50 to 40,000 s{sup -1}. The rheological properties of a commercial MR fluid, as well as a newly developed MR polymeric gel, and a ferrofluid-based MR fluid are investigated. The results for apparent viscosity and dynamic and static shear stresses under different applied magnetic fields are reported. (orig.)

  11. Modified bond model for shear in slabs under concentrated loads

    NARCIS (Netherlands)

    Lantsoght, E.O.L.; Van der Veen, C.; De Boer, A.

    2015-01-01

    Slabs subjected to concentrated loads close to supports, as occurring for truck loads on slab bridges, are less studied than beams in shear or slab-column connections in punching. To predict the shear capacity for this case, the Bond Model for concentric punching shear was studied initially.

  12. Inelastic deformations of fault and shear zones in granitic rock

    International Nuclear Information System (INIS)

    Wilder, D.G.

    1986-02-01

    Deformations during heating and cooling of three drifts in granitic rock were influenced by the presence of faults and shear zones. Thermal deformations were significantly larger in sheared and faulted zones than where the rock was jointed, but neither sheared nor faulted. Furthermore, thermal deformations in faulted or sheared rock were not significantly recovered during subsequent cooling, thus a permanent deformation remained. This inelastic response is in contrast with elastic behavior identified in unfaulted and unsheared rock segments. A companion paper indicates that deformations in unsheared or unfaulted rock were effectively modeled as an elastic response. We conclude that permanent deformations occurred in fractures with crushed minerals and fracture filling or gouge materials. Potential mechanisms for this permanent deformation are asperity readjustments during thermal deformations, micro-shearing, asperity crushing and crushing of the secondary fracture filling minerals. Additionally, modulus differences in sheared or faulted rock as compared to more intact rock would result in greater deformations in response to the same thermal loads

  13. Earthquake induced rock shear through a deposition hole. Influence of shear plane inclination and location as well as buffer properties on the damage caused to the canister

    International Nuclear Information System (INIS)

    Boergesson, Lennart; Hernelind, Jan

    2006-10-01

    The effect on the canister of an earthquake induced 20 cm rock shear with the shear rate 1 m/s along a fracture intersecting a deposition hole in a KBS-V repository has been investigated for a number of different shear cases and for different properties of the buffer material. The scenarios have been modelled with the finite element method and calculations have been done using the code ABAQUS. D-element models of the rock, the buffer and the canister have been used. Contact elements that can model separation have been used for the interfaces between the buffer and the rock and the interfaces between the buffer and the canister. The influence of mainly the following factors has been investigated: 1. Inclination of the intersecting fracture. 2. Shear direction when the fracture is not horizontal (inclination deviates from 90 deg). 3. Location of the shear plane when the inclination is 90 deg. 4. Magnitude of the shear displacement. 5. Bentonite type. 6. Bentonite density. 7. Transformation of the buffer to illite or cemented bentonite. The results from the calculations show that all these factors have important influence on the damage of the canister but the influence is for most factors not easily described since there are mutual interferences between the different factors. Plastic strain larger than 1% was reached in the copper already at 10 cm shear in all cases with Na- and Ca- bentonite. However, for several cases of Na-bentonite and one case of Ca-bentonite such plastic strain was only reached in the lid. The plastic strain in the steel was generally smaller than in the copper mainly due to the higher yield stress in the steel. For all cases of Na-bentonite except one and for about half of the Ca-bentonite cases the plastic strain in the steel was smaller than 1% after 10 cm shear. The shear inclination 45 deg was more harmful for the copper tube than the shear inclination 90 deg when tension shear was considered. At the shear inclinations 45 deg and 22.5 deg

  14. Earthquake induced rock shear through a deposition hole. Influence of shear plane inclination and location as well as buffer properties on the damage caused to the canister

    Energy Technology Data Exchange (ETDEWEB)

    Boergesson, Lennart [Clay Technology AB, Lund (Sweden); Hernelind, Jan [5T Engineering AB, Vaesteraas (Sweden)

    2006-10-15

    The effect on the canister of an earthquake induced 20 cm rock shear with the shear rate 1 m/s along a fracture intersecting a deposition hole in a KBS-V repository has been investigated for a number of different shear cases and for different properties of the buffer material. The scenarios have been modelled with the finite element method and calculations have been done using the code ABAQUS. D-element models of the rock, the buffer and the canister have been used. Contact elements that can model separation have been used for the interfaces between the buffer and the rock and the interfaces between the buffer and the canister. The influence of mainly the following factors has been investigated: 1. Inclination of the intersecting fracture. 2. Shear direction when the fracture is not horizontal (inclination deviates from 90 deg). 3. Location of the shear plane when the inclination is 90 deg. 4. Magnitude of the shear displacement. 5. Bentonite type. 6. Bentonite density. 7. Transformation of the buffer to illite or cemented bentonite. The results from the calculations show that all these factors have important influence on the damage of the canister but the influence is for most factors not easily described since there are mutual interferences between the different factors. Plastic strain larger than 1% was reached in the copper already at 10 cm shear in all cases with Na- and Ca- bentonite. However, for several cases of Na-bentonite and one case of Ca-bentonite such plastic strain was only reached in the lid. The plastic strain in the steel was generally smaller than in the copper mainly due to the higher yield stress in the steel. For all cases of Na-bentonite except one and for about half of the Ca-bentonite cases the plastic strain in the steel was smaller than 1% after 10 cm shear. The shear inclination 45 deg was more harmful for the copper tube than the shear inclination 90 deg when tension shear was considered. At the shear inclinations 45 deg and 22.5 deg

  15. High Resolution Shear Profile Measurements in Entangled Polymers

    KAUST Repository

    Hayes, Keesha A.; Buckley, Mark R.; Cohen, Itai; Archer, Lynden A.

    2008-01-01

    spanning a wide range of molecular weights and number of entanglements (8≤Z≤56), but reveal large differences between the imposed and measured shear rates. These findings disagree with recent reports that shear banding is a characteristic flow response

  16. Shear modulation experiments with ECCD on TCV

    International Nuclear Information System (INIS)

    Cirant, S.; Alberti, S.; Gandini, F.; Behn, R.; Goodman, T.P.; Nikkola, P.

    2006-01-01

    Anomalous electron transport is determined by turbulence, which in turn is affected by magnetic shear. A novel application of electron cyclotron current drive (ECCD), aiming at localized shear modulation, has been applied on the TCV tokamak for experiments on shear-dependent electron transport. Pairs of EC beams, absorbed at the same radius, with one oriented for co- and the other for counter-injection, are modulated out of phase in order to force a local modulation of current-density at constant input power. Off-axis deposition (ρ dep = 0.24) is performed to avoid the central region, where the low heat flux would make transport analysis difficult. In addition some sawteeth control is achieved in this way. A significant impact on local shear is achieved with I ECCD ∼ 0.1I OH , even when the modulation period is much shorter than the current diffusion time across the whole plasma radius. The main result is that although source (heat and particle) terms are constant, both electron density and temperature are modulated during alternated ECCD. Once equilibrium effects are taken into account for appropriate mapping of Thomson scattering measurements onto flux coordinates, modulation of T e and electron pressure, peaked on-axis, is confirmed at all radii internal to EC deposition. The best confinement occurs for co-injection, in which case a local decrease (∼55%) in the magnetic shear causes a decrease in the electron thermal diffusivity of a similar amount (∼65%)

  17. Temperature and shear rate characteristics of electrorheological gel applied to a clutch

    International Nuclear Information System (INIS)

    Koyanagi, K; Takata, Y; Motoyoshi, T; Oshima, T; Kakinuma, Y; Anzai, H; Sakurai, K

    2013-01-01

    This investigation reports the physical characteristics of electrorheological (ER) gels, which are a type of functional material having controlled surface friction. We previously developed slip clutches using ER gels sandwiched between electrodes, and verified their responses and controllability. We newly report the temperature and shear rate characteristics of ER gel in this study because the input and output electrodes of the clutch continuously slip past each other. While the temperature of ER gels increased when energized, the shear stress hardly changed. Instead, wearing and adaptation to the electrode affect the property. The shear rate hardly affected the shear stress in the high-shear-rate region. Conversely, the shear stress depended on the shear rate in the lower region.

  18. Development of shear bands in amorphous-crystalline metallic alloys

    International Nuclear Information System (INIS)

    Pozdnyakov, V.A.

    2004-01-01

    A theoretical study is made into conditions of shear band evolution in amorphous-crystalline alloys with various morphological types of structural constituents. The condition of shear band evolution in thin amorphous alloys in the interior of the crystalline matrix is obtained. It is shown that a scale effect exists which manifests itself in suppression of the process of localized plastic flow with amorphous alloy thickness decreasing down to the limit. The analysis of the condition for shear band evolution in an amorphous alloy with nanocrystalline inclusions is accomplished. The relationship of a critical stress of shear band evolution to a volume fraction of disperse crystal inclusions is obtained. A consideration is also given to the evolution of shear bands in the material containing amorphous and crystalline areas of micro meter size. For the alloy with the structure of this type conditions for propagation of localized flows by a relay race type mechanism are determined [ru

  19. An experimental investigation for external RC shear wall applications

    Science.gov (United States)

    Kaltakci, M. Y.; Ozturk, M.; Arslan, M. H.

    2010-09-01

    The strength and rigidity of most reinforced concrete (RC) buildings in Turkey, which are frequently hit by destructive earthquakes, is not at a sufficient level. Therefore, the result of earthquakes is a significant loss of life and property. The strengthening method most commonly preferred for these type of RC buildings is the application of RC infilled walls (shear walls) in the frame openings of the building. However, since the whole building has to be emptied and additional heavy costs arise during this type of strengthening, users prefer not to strengthen their buildings despite the heavy risk they are exposed to. Therefore, it is necessary to develop easier-to-apply and more effective methods for the rapid strengthening of housing and the heavily-used public buildings which cannot be emptied during the strengthening process (such as hospitals and schools). This study empirically analyses the different methods of a new system which can meet this need. In this new system, named "external shear wall application", RC shear walls are applied on the external surface of the building, along the frame plane rather than in the building. To this end, 7 test samples in 1/2 and 1/3 geometrical scale were designed to analyse the efficiency of the strengthening technique where the shear wall leans on the frame from outside of the building (external shear wall application) and of the strengthening technique where a specific space is left between the frame and the external shear wall by using a coupling beam to connect elements (application of external shear wall with coupling beam). Test results showed that the maximum lateral load capacity, initial rigidity and energy dissipation behaviours of the samples strengthened with external shear wall were much better than those of the bare frames.

  20. An experimental investigation for external RC shear wall applications

    Directory of Open Access Journals (Sweden)

    M. Y. Kaltakci

    2010-09-01

    Full Text Available The strength and rigidity of most reinforced concrete (RC buildings in Turkey, which are frequently hit by destructive earthquakes, is not at a sufficient level. Therefore, the result of earthquakes is a significant loss of life and property. The strengthening method most commonly preferred for these type of RC buildings is the application of RC infilled walls (shear walls in the frame openings of the building. However, since the whole building has to be emptied and additional heavy costs arise during this type of strengthening, users prefer not to strengthen their buildings despite the heavy risk they are exposed to. Therefore, it is necessary to develop easier-to-apply and more effective methods for the rapid strengthening of housing and the heavily-used public buildings which cannot be emptied during the strengthening process (such as hospitals and schools. This study empirically analyses the different methods of a new system which can meet this need. In this new system, named "external shear wall application", RC shear walls are applied on the external surface of the building, along the frame plane rather than in the building. To this end, 7 test samples in 1/2 and 1/3 geometrical scale were designed to analyse the efficiency of the strengthening technique where the shear wall leans on the frame from outside of the building (external shear wall application and of the strengthening technique where a specific space is left between the frame and the external shear wall by using a coupling beam to connect elements (application of external shear wall with coupling beam. Test results showed that the maximum lateral load capacity, initial rigidity and energy dissipation behaviours of the samples strengthened with external shear wall were much better than those of the bare frames.

  1. Shear crack formation and propagation in reinforced Engineered Cementitious Composites

    DEFF Research Database (Denmark)

    Paegle, Ieva; Fischer, Gregor

    2011-01-01

    capacity of beams loaded primarily in shear. The experimental program consists of ECC with short randomly distributed polyvinyl alcohol (PVA) fiber beams with different stirrup arrangements and conventional reinforced concrete (R/C) counterparts for comparison. The shear crack formation mechanism of ECC......This paper describes an experimental investigation of the shear behaviour of beams consisting of steel reinforced Engineered Cementitious Composites (R/ECC). Based on the strain hardening and multiple cracking behaviour of ECC, this study investigates the extent to which ECC influences the shear...

  2. Hemolysis in a laminar flow-through Couette shearing device: an experimental study.

    Science.gov (United States)

    Boehning, Fiete; Mejia, Tzahiry; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2014-09-01

    Reducing hemolysis has been one of the major goals of rotary blood pump development and in the investigational phase, the capability of hemolysis estimation for areas of elevated shear stresses is valuable. The degree of hemolysis is determined by the amplitude of shear stress and the exposure time, but to date, the exact hemolytic behavior at elevated shear stresses and potential thresholds for subcritical shear exposure remain vague. This study provides experimental hemolysis data for a set of shear stresses and exposure times to allow better estimations of hemolysis for blood exposed to elevated shearing. Heparinized porcine blood with a hematocrit of 40% was mechanically damaged in a flow-through laminar Couette shear flow at a temperature of 23°C. Four levels of shear stress, 24, 592, 702, and 842 Pa, were replicated at two exposure times, 54 and 873 ms. For the calculation of the shear stresses, an apparent viscosity of 5 mPas was used, which was verified in an additional measurement of the blood viscosity. The hemolysis measurements were repeated four times, whereby all conditions were measured once within the same day and with blood from the same source. Samples were taken at the inlet and outlet of the shear region and an increase in plasma-free hemoglobin was measured. An index of hemolysis (IH) was thereby calculated giving the ratio of free to total hemoglobin. The results are compared with data from previously published studies using a similar shearing device. Hemolysis was found to increase exponentially with shear stress, but high standard deviations existed at measurements with elevated IH. At short exposure times, the IH remained low at under 0.5% for all shear stress levels. For high exposure times, the IH increased from 0.84% at 592 Pa up to 3.57% at the highest shear stress level. Hemolysis was significant for shear stresses above ∼600 Pa at the high exposure time of 873 ms. Copyright © 2014 International Center for Artificial

  3. Shear Adhesion of Tapered Nanopillar Arrays.

    Science.gov (United States)

    Cho, Younghyun; Minsky, Helen K; Jiang, Yijie; Yin, Kaiyang; Turner, Kevin T; Yang, Shu

    2018-04-04

    Tapered nanopillars with various cross sections, including cone-shaped, stepwise, and pencil-like structures (300 nm in diameter at the base of the pillars and 1.1 μm in height), are prepared from epoxy resin templated by nanoporous anodic aluminum oxide (AAO) membranes. The effect of pillar geometry on the shear adhesion behavior of these nanopillar arrays is investigated via sliding experiments in a nanoindentation system. In a previous study of arrays with the same geometry, it was shown that cone-shaped nanopillars exhibit the highest adhesion under normal loading while stepwise and pencil-like nanopillars exhibit lower normal adhesion strength due to significant deformation of the pillars that occurs with increasing indentation depth. Contrary to the previous studies, here, we show that pencil-like nanopillars exhibit the highest shear adhesion strength at all indentation depths among three types of nanopillar arrays and that the shear adhesion increases with greater indentation depth due to the higher bending stiffness and closer packing of the pencil-like nanopillar array. Finite element simulations are used to elucidate the deformation of the pillars during the sliding experiments and agree with the nanoindentation-based sliding measurements. The experiments and finite element simulations together demonstrate that the shape of the nanopillars plays a key role in shear adhesion and that the mechanism is quite different from that of adhesion under normal loading.

  4. Ab initio study of Ni2MnGa under shear deformation

    Directory of Open Access Journals (Sweden)

    Zelený Martin

    2015-01-01

    Full Text Available The effect of shear deformation on Ni2MnGa magnetic shape memory alloy has been investigated using ab initio electronic structure calculations. We used the projector-augmented wave method for the calculations of total energies and stresses as functions of applied affine shear deformation. The studied nonmodulated martensite (NM phase exhibits a tetragonally distorted L21 structure with c/a > 1. A large strain corresponding to simple shears in {001}, {100} and {100} systems was applied to describe a full path between two equivalent NM lattices. We also studied {101} shear which is related to twining of NM phase. Twin reorientation in this system is possible, because applied positive shear results in path with significantly smaller energetic barrier than for negative shear and for shears in other studied systems. When the full relaxation of lattice parameters is allowed, the barriers further strongly decrease and the structures along the twinning path can be considered as orthorhombic.

  5. Mechanical properties of jammed packings of frictionless spheres under an applied shear stress

    International Nuclear Information System (INIS)

    Liu Hao; Tong Hua; Xu Ning

    2014-01-01

    By minimizing a thermodynamic-like potential, we unbiasedly sample the potential energy landscape of soft and frictionless spheres under a constant shear stress. We obtain zero-temperature jammed states under desired shear stresses and investigate their mechanical properties as a function of the shear stress. As a comparison, we also obtain the jammed states from the quasistatic-shear sampling in which the shear stress is not well-controlled. Although the yield stresses determined by both samplings show the same power-law scaling with the compression from the jamming transition point J at zero temperature and shear stress, for finite size systems the quasistatic-shear sampling leads to a lower yield stress and a higher critical volume fraction at point J. The shear modulus of the jammed solids decreases with increasing shear stress. However, the shear modulus does not decay to zero at yielding. This discontinuous change of the shear modulus implies the discontinuous nature of the unjamming transition under nonzero shear stress, which is further verified by the observation of a discontinuous jump in the pressure from the jammed solids to the shear flows. The pressure jump decreases upon decompression and approaches zero at the critical-like point J, in analogy with the well-known phase transitions under an external field. The analysis of the force networks in the jammed solids reveals that the force distribution is more sensitive to the increase of the shear stress near point J. The force network anisotropy increases with increasing shear stress. The weak particle contacts near the average force and under large shear stresses it exhibit an asymmetric angle distribution. (special topic — non-equilibrium phenomena in soft matters)

  6. Shear strength properties of naturally occurring bituminous sands

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2009-06-01

    Full Text Available because of the cohesive nature of bitumen contents. However, results from the direct shear tests were comparable to properties of oil sands reported earlier from various other laboratory tests. Based on the direct shear test results, Mohr-Coulomb failure...

  7. Structural behavior of human lumbar intervertebral disc under direct shear.

    Science.gov (United States)

    Schmidt, Hendrik; Häussler, Kim; Wilke, Hans-Joachim; Wolfram, Uwe

    2015-03-18

    The intervertebral disc (IVD) is a complex, flexible joint between adjacent vertebral bodies that provides load transmission while permitting movements of the spinal column. Finite element models can be used to help clarify why and how IVDs fail or degenerate. To do so, it is of importance to validate those models against controllable experiments. Due to missing experimental data, shear properties are not used thus far in validating finite element models. This study aimed to investigate the structural shear properties of human lumbar IVDs in posteroanterior (PA) and laterolateral (LL) loading directions. Fourteen lumbar IVDs (median age: 49 years) underwent direct shear in PA and LL loading directions. A custom-build shear device was used in combination with a materials testing machine to load the specimens until failure. Shear stiffness, ultimate shear force and displacement, and work to failure were determined. Each specimen was tested until complete or partial disruption. Median stiffness in PA direction was 490 N/mm and in LL direction 568 N/mm. Median ultimate shear force in the PA direction was 2,877 N and in the LL direction 3,199 N. Work to failure was 12 Nm in the PA and 9 Nm in the LL direction. This study was an experiment to subject IVDs to direct shear. The results could help us to understand the structure and function of IVDs with regard to mechanical spinal stability, and they can be used to validate finite element models of the IVD.

  8. Phase Aberration and Attenuation Effects on Acoustic Radiation Force-Based Shear Wave Generation.

    Science.gov (United States)

    Carrascal, Carolina Amador; Aristizabal, Sara; Greenleaf, James F; Urban, Matthew W

    2016-02-01

    Elasticity is measured by shear wave elasticity imaging (SWEI) methods using acoustic radiation force to create the shear waves. Phase aberration and tissue attenuation can hamper the generation of shear waves for in vivo applications. In this study, the effects of phase aberration and attenuation in ultrasound focusing for creating shear waves were explored. This includes the effects of phase shifts and amplitude attenuation on shear wave characteristics such as shear wave amplitude, shear wave speed, shear wave center frequency, and bandwidth. Two samples of swine belly tissue were used to create phase aberration and attenuation experimentally. To explore the phase aberration and attenuation effects individually, tissue experiments were complemented with ultrasound beam simulations using fast object-oriented C++ ultrasound simulator (FOCUS) and shear wave simulations using finite-element-model (FEM) analysis. The ultrasound frequency used to generate shear waves was varied from 3.0 to 4.5 MHz. Results: The measured acoustic pressure and resulting shear wave amplitude decreased approximately 40%-90% with the introduction of the tissue samples. Acoustic intensity and shear wave displacement were correlated for both tissue samples, and the resulting Pearson's correlation coefficients were 0.99 and 0.97. Analysis of shear wave generation with tissue samples (phase aberration and attenuation case), measured phase screen, (only phase aberration case), and FOCUS/FEM model (only attenuation case) showed that tissue attenuation affected the shear wave generation more than tissue aberration. Decreasing the ultrasound frequency helped maintain a focused beam for creation of shear waves in the presence of both phase aberration and attenuation.

  9. Modeling Shear Induced Von Willebrand Factor Binding to Collagen

    Science.gov (United States)

    Dong, Chuqiao; Wei, Wei; Morabito, Michael; Webb, Edmund; Oztekin, Alparslan; Zhang, Xiaohui; Cheng, Xuanhong

    2017-11-01

    Von Willebrand factor (vWF) is a blood glycoprotein that binds with platelets and collagen on injured vessel surfaces to form clots. VWF bioactivity is shear flow induced: at low shear, binding between VWF and other biological entities is suppressed; for high shear rate conditions - as are found near arterial injury sites - VWF elongates, activating its binding with platelets and collagen. Based on parameters derived from single molecule force spectroscopy experiments, we developed a coarse-grain molecular model to simulate bond formation probability as a function of shear rate. By introducing a binding criterion that depends on the conformation of a sub-monomer molecular feature of our model, the model predicts shear-induced binding, even for conditions where binding is highly energetically favorable. We further investigate the influence of various model parameters on the ability to predict shear-induced binding (vWF length, collagen site density and distribution, binding energy landscape, and slip/catch bond length) and demonstrate parameter ranges where the model provides good agreement with existing experimental data. Our results may be important for understanding vWF activity and also for achieving targeted drug therapy via biomimetic synthetic molecules. National Science Foundation (NSF),Division of Mathematical Sciences (DMS).

  10. Displacement-length scaling of brittle faults in ductile shear.

    Science.gov (United States)

    Grasemann, Bernhard; Exner, Ulrike; Tschegg, Cornelius

    2011-11-01

    Within a low-grade ductile shear zone, we investigated exceptionally well exposed brittle faults, which accumulated antithetic slip and rotated into the shearing direction. The foliation planes of the mylonitic host rock intersect the faults approximately at their centre and exhibit ductile reverse drag. Three types of brittle faults can be distinguished: (i) Faults developing on pre-existing K-feldspar/mica veins that are oblique to the shear direction. These faults have triclinic flanking structures. (ii) Wing cracks opening as mode I fractures at the tips of the triclinic flanking structures, perpendicular to the shear direction. These cracks are reactivated as faults with antithetic shear, extend from the parent K-feldspar/mica veins and form a complex linked flanking structure system. (iii) Joints forming perpendicular to the shearing direction are deformed to form monoclinic flanking structures. Triclinic and monoclinic flanking structures record elliptical displacement-distance profiles with steep displacement gradients at the fault tips by ductile flow in the host rocks, resulting in reverse drag of the foliation planes. These structures record one of the greatest maximum displacement/length ratios reported from natural fault structures. These exceptionally high ratios can be explained by localized antithetic displacement along brittle slip surfaces, which did not propagate during their rotation during surrounding ductile flow.

  11. Displacement–length scaling of brittle faults in ductile shear

    Science.gov (United States)

    Grasemann, Bernhard; Exner, Ulrike; Tschegg, Cornelius

    2011-01-01

    Within a low-grade ductile shear zone, we investigated exceptionally well exposed brittle faults, which accumulated antithetic slip and rotated into the shearing direction. The foliation planes of the mylonitic host rock intersect the faults approximately at their centre and exhibit ductile reverse drag. Three types of brittle faults can be distinguished: (i) Faults developing on pre-existing K-feldspar/mica veins that are oblique to the shear direction. These faults have triclinic flanking structures. (ii) Wing cracks opening as mode I fractures at the tips of the triclinic flanking structures, perpendicular to the shear direction. These cracks are reactivated as faults with antithetic shear, extend from the parent K-feldspar/mica veins and form a complex linked flanking structure system. (iii) Joints forming perpendicular to the shearing direction are deformed to form monoclinic flanking structures. Triclinic and monoclinic flanking structures record elliptical displacement–distance profiles with steep displacement gradients at the fault tips by ductile flow in the host rocks, resulting in reverse drag of the foliation planes. These structures record one of the greatest maximum displacement/length ratios reported from natural fault structures. These exceptionally high ratios can be explained by localized antithetic displacement along brittle slip surfaces, which did not propagate during their rotation during surrounding ductile flow. PMID:26806996

  12. Interaction of equal-size bubbles in shear flow.

    Science.gov (United States)

    Prakash, Jai; Lavrenteva, Olga M; Byk, Leonid; Nir, Avinoam

    2013-04-01

    The inertia-induced forces on two identical spherical bubbles in a simple shear flow at small but finite Reynolds number, for the case when the bubbles are within each other's inner viscous region, are calculated making use of the reciprocal theorem. This interaction force is further employed to model the dynamics of air bubbles injected to a viscous fluid sheared in a Couette device at the first shear flow instability where the bubbles are trapped inside the stable Taylor vortex. It was shown that, during a long time scale, the inertial interaction between the bubbles in the primary shear flow drives them away from each other and, as a result, equal-size bubbles eventually assume an ordered string with equal separation distances between all neighbors. We report on experiments showing the dynamic evolution of various numbers of bubbles. The results of the theory are in good agreement with the experimental observations.

  13. Shear dilatancy and acoustic emission in dry and saturated granular materials

    Science.gov (United States)

    Brodsky, E. E.; Siman-Tov, S.

    2017-12-01

    Shearing of granular materials plays a strong role in naturally sheared systems as landslides and faults. Many works on granular flows have concentrated on dry materials, but relatively little work has been done on water saturated sands. Here we experimentally investigate dry versus saturated quartz-rich sand to understand the effect of the fluid medium on the rheology and acoustic waves emission of the sheared sand. The sand was sheared in a rotary shear rheometer under applied constant normal stress boundary at low (100 µm/s) to high (1 m/s) velocities. Mechanical, acoustic data and deformation were continuously recorded and imaged. For dry and water saturated experiments the granular volume remains constant for low shear velocities ( 10-3 m/s) and increases during shearing at higher velocities ( 1 m/s). Continuous imaging of the sheared sand show that the steady state shear band thickness is thicker during the high velocity steps. No significant change observed in the shear band thickness between dry and water saturated experiments. In contrast, the amount of dilation during water saturated experiments is about half the value measured for dry material. The measured decrease cannot be explained by shear band thickness change as such is not exist. However, the reduced dilation is supported by our acoustic measurements. In general, the event rate and acoustic event amplitudes increase with shear velocity. While isolated events are clearly detected during low velocities at higher the events overlap, resulting in a noisy signal. Although detection is better for saturated experiments, during the high velocity steps the acoustic energy measured from the signal is lower compared to that recorded for dry experiments. We suggest that the presence of fluid suppresses grain motion and particles impacts leading to mild increase in the internal pressure and therefore for the reduced dilation. In addition, the viscosity of fluids may influence the internal pressure via

  14. The roles of electric field shear and Shafranov shift in sustaining high confinement in enhanced reversed shear plasmas on the TFTR tokamak

    International Nuclear Information System (INIS)

    Synakowski, E.J.; Beer, M.A.

    1997-02-01

    The relaxation of core transport barriers in TFTR Enhanced Reversed Shear plasmas has been studied by varying the radial electric field using different applied torques from neutral beam injection. Transport rates and fluctuations remain low over a wide range of radial electric field shear, but increase when the local E x B shearing rates are driven below a threshold comparable to the fastest linear growth rates of the dominant instabilities. Shafranov-shift-induced stabilization alone is not able to sustain enhanced confinement

  15. Shear layer flame stabilization sensitivities in a swirling flow

    Directory of Open Access Journals (Sweden)

    Christopher Foley

    2017-03-01

    Full Text Available A variety of different flame configurations and heat release distributions exist in high swirl, annular flows, due to the existence of inner and outer shear layers as well a vortex breakdown bubble. Each of these different configurations, in turn, has different thermoacoustic sensitivities and influences on combustor emissions, nozzle durability, and liner heating. This paper presents findings on the sensitivities of the outer shear layer- stabilized flames to a range of parameters, including equivalence ratio, bulkhead temperature, flow velocity, and preheat temperature. There is significant hysteresis for flame attachment/detachment from the outer shear layer and this hysteresis is also described. Results are also correlated with extinction stretch rate calculations based on detailed kinetic simulations. In addition, we show that the bulkhead temperature near the flame attachment point has significant impact on outer shear layer detachment. This indicates that understanding the heat transfer between the edge flame stabilized in the shear layer and the nozzle hardware is needed in order to predict shear layer flame stabilization limits. Moreover, it shows that simulations cannot simply assume adiabatic boundary conditions if they are to capture these transitions. We also show that the reference temperature for correlating these transitions is quite different for attachment and local blow off. Finally, these results highlight the deficiencies in current understanding of the influence of fluid mechanic parameters (e.g. velocity, swirl number on shear layer flame attachment. For example, they show that the seemingly simple matter of scaling flame transition points with changes in flow velocities is not understood.

  16. Shear and extensional properties of kefiran.

    Science.gov (United States)

    Piermaría, Judith; Bengoechea, Carlos; Abraham, Analía Graciela; Guerrero, Antonio

    2016-11-05

    Kefiran is a neutral polysaccharide constituted by glucose and galactose produced by Lactobacillus kefiranofaciens. It is included into kefir grains and has several health promoting properties. In the present work, shear and extensional properties of different kefiran aqueous dispersions (0.5, 1 and 2% wt.) were assessed and compared to other neutral gums commonly used in food, cosmetic and pharmaceutics industries (methylcellulose, locust bean gum and guar gum). Kefiran showed shear flow characteristics similar to that displayed by other representative neutral gums, although it always yielded lower viscosities at a given concentration. For each gum system it was possible to find a correlation between dynamic and steady shear properties by a master curve including both the apparent and complex viscosities. When studying extensional properties of selected gums at 2% wt. by means of a capillary break-up rheometer, kefiran solutions did not show important extensional properties, displaying a behaviour close the Newtonian. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Alfven eigenmodes in shear reversed plasmas

    International Nuclear Information System (INIS)

    Breizman, B.N.; Berk, H.L.; Pekker, M.S.; Sharapov, S.E.; Hawkes, N.C.; Borba, D.N.; Pinches, S.D.

    2003-01-01

    Experiments on JT-60U and JET have shown that plasma configurations with shear reversal are prone to the excitation of unusual Alfven Eigenmodes by energetic particles. These modes emerge outside the TAE frequency gap, where one might expect them to be strongly damped. The modes often appear in bunches and they exhibit a quasi-periodic pattern of predominantly upward frequency sweeping (Alfven Cascades) as the safety factor q changes in time. This work presents a theory that explains the key features of the observed unusual modes including their connection to TAE's as well as the modifications of TAE's themselves near the shear reversal point. The developed theory has been incorporated into a reduced numerical model and verified with full geometry codes. JET experimental data on Alfven spectroscopy have been simulated to infer the mode numbers and the evolution of q min in the discharge. This analysis confirms the values of q that characterize the internal transport barrier triggering in reversed shear plasmas. (author)

  18. On shear rheology of gel propellants

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, Shai; Peretz, Arie [RAFAEL, MANOR Propulsion and Explosive Systems Division, Haifa (Israel); Natan, Benveniste [Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, Haifa (Israel)

    2007-04-15

    Selected fuel, oxidizer and simulant gels were prepared and rheologically characterized using a rotational rheometer. For fuel gelation both organic and inorganic gellants were utilized, whereas oxidizers and simulants were gelled with addition of silica and polysaccharides, respectively. The generalized Herschel-Bulkley constitutive model was found to most adequately represent the gels studied. Hydrazine-based fuels, gelled with polysaccharides, were characterized as shear-thinning pseudoplastic fluids with low shear yield stress, whereas inhibited red-fuming nitric acid (IRFNA) and hydrogen peroxide oxidizers, gelled with silica, were characterized as yield thixotropic fluids with significant shear yield stress. Creep tests were conducted on two rheological types of gels with different gellant content and the results were fitted by Burgers-Kelvin viscoelastic constitutive model. The effect of temperature on the rheological properties of gel propellant simulants was also investigated. A general rheological classification of gel propellants and simulants is proposed. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  19. Midbroken Reinforced Concrete Shear Frames Due to Earthquakes

    DEFF Research Database (Denmark)

    Köylüoglu, H. U.; Cakmak, A. S.; Nielsen, Søren R. K.

    A non-linear hysteretic model for the response and local damage analyses of reinforced concrete shear frames subject to earthquake excitation is proposed, and, the model is applied to analyse midbroken reinforced concrete (RC) structures due to earthquake loads. Each storey of the shear frame...

  20. High Resolution Shear Profile Measurements in Entangled Polymers

    KAUST Repository

    Hayes, Keesha A.

    2008-11-17

    We use confocal microscopy and particle image velocimetry to visualize motion of 250-300 nm. fluorescent tracer particles in entangled polymers subject to a rectilinear shear flow. Our results show linear velocity profiles in polymer solutions spanning a wide range of molecular weights and number of entanglements (8≤Z≤56), but reveal large differences between the imposed and measured shear rates. These findings disagree with recent reports that shear banding is a characteristic flow response of entangled polymers, and instead point to interfacial slip as an important source of strain loss. © 2008 The American Physical Society.

  1. Shear viscosities of photons in strongly coupled plasmas

    Directory of Open Access Journals (Sweden)

    Di-Lun Yang

    2016-09-01

    Full Text Available We investigate the shear viscosity of thermalized photons in the quark gluon plasma (QGP at weak coupling and N=4 super Yang–Mills plasma (SYMP at both strong and weak couplings. We find that the shear viscosity due to the photon–parton scattering up to the leading order of electromagnetic coupling is suppressed when the coupling of the QGP/SYMP is increased, which stems from the blue-shift of the thermal-photon spectrum at strong coupling. In addition, the shear viscosity rapidly increases near the deconfinement transition in a phenomenological model analogous to the QGP.

  2. Profile control studies for JET optimised shear regime

    Energy Technology Data Exchange (ETDEWEB)

    Litaudon, X.; Becoulet, A.; Eriksson, L.G.; Fuchs, V.; Huysmans, G.; How, J.; Moreau, D.; Rochard, F.; Tresset, G.; Zwingmann, W. [Association Euratom-CEA, CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee, DRFC, 13 - Saint-Paul-lez-Durance (France); Bayetti, P.; Joffrin, E.; Maget, P.; Mayorat, M.L.; Mazon, D.; Sarazin, Y. [JET Abingdon, Oxfordshire (United Kingdom); Voitsekhovitch, I. [Universite de Provence, LPIIM, Aix-Marseille 1, 13 (France)

    2000-03-01

    This report summarises the profile control studies, i.e. preparation and analysis of JET Optimised Shear plasmas, carried out during the year 1999 within the framework of the Task-Agreement (RF/CEA/02) between JET and the Association Euratom-CEA/Cadarache. We report on our participation in the preparation of the JET Optimised Shear experiments together with their comprehensive analyses and the modelling. Emphasis is put on the various aspects of pressure profile control (core and edge pressure) together with detailed studies of current profile control by non-inductive means, in the prospects of achieving steady, high performance, Optimised Shear plasmas. (authors)

  3. Scaling results for the magnetic field line trajectories in the stochastic layer near the separatrix in divertor tokamaks with high magnetic shear using the higher shear map

    International Nuclear Information System (INIS)

    Punjabi, Alkesh; Ali, Halima; Farhat, Hamidullah

    2009-01-01

    Extra terms are added to the generating function of the simple map (Punjabi et al 1992 Phys. Rev. Lett. 69 3322) to adjust shear of magnetic field lines in divertor tokamaks. From this new generating function, a higher shear map is derived from a canonical transformation. A continuous analog of the higher shear map is also derived. The method of maps (Punjabi et al 1994 J. Plasma Phys. 52 91) is used to calculate the average shear, stochastic broadening of the ideal separatrix near the X-point in the principal plane of the tokamak, loss of poloidal magnetic flux from inside the ideal separatrix, magnetic footprint on the collector plate, and its area, and the radial diffusion coefficient of magnetic field lines near the X-point. It is found that the width of the stochastic layer near the X-point and the loss of poloidal flux from inside the ideal separatrix scale linearly with average shear. The area of magnetic footprints scales roughly linearly with average shear. Linear scaling of the area is quite good when the average shear is greater than or equal to 1.25. When the average shear is in the range 1.1-1.25, the area of the footprint fluctuates (as a function of average shear) and scales faster than linear scaling. Radial diffusion of field lines near the X-point increases very rapidly by about four orders of magnitude as average shear increases from about 1.15 to 1.5. For higher values of average shear, diffusion increases linearly, and comparatively very slowly. The very slow scaling of the radial diffusion of the field can flatten the plasma pressure gradient near the separatrix, and lead to the elimination of type-I edge localized modes.

  4. Designing shear-thinning

    Science.gov (United States)

    Nelson, Arif Z.; Ewoldt, Randy H.

    2017-11-01

    Design in fluid mechanics often focuses on optimizing geometry (airfoils, surface textures, microfluid channels), but here we focus on designing fluids themselves. The dramatically shear-thinning ``yield-stress fluid'' is currently the most utilized non-Newtonian fluid phenomenon. These rheologically complex materials, which undergo a reversible transition from solid-like to liquid-like fluid flow, are utilized in pedestrian products such as paint and toothpaste, but also in emerging applications like direct-write 3D printing. We present a paradigm for yield-stress fluid design that considers constitutive model representation, material property databases, available predictive scaling laws, and the many ways to achieve a yield stress fluid, flipping the typical structure-to-rheology analysis to become the inverse: rheology-to-structure with multiple possible materials as solutions. We describe case studies of 3D printing inks and other flow scenarios where designed shear-thinning enables performance remarkably beyond that of Newtonian fluids. This work was supported by Wm. Wrigley Jr. Company and the National Science Foundation under Grant No. CMMI-1463203.

  5. Microfluidic thrombosis under multiple shear rates and antiplatelet therapy doses.

    Directory of Open Access Journals (Sweden)

    Melissa Li

    Full Text Available The mainstay of treatment for thrombosis, the formation of occlusive platelet aggregates that often lead to heart attack and stroke, is antiplatelet therapy. Antiplatelet therapy dosing and resistance are poorly understood, leading to potential incorrect and ineffective dosing. Shear rate is also suspected to play a major role in thrombosis, but instrumentation to measure its influence has been limited by flow conditions, agonist use, and non-systematic and/or non-quantitative studies. In this work we measured occlusion times and thrombus detachment for a range of initial shear rates (500, 1500, 4000, and 10000 s(-1 and therapy concentrations (0-2.4 µM for eptifibatide, 0-2 mM for acetyl-salicylic acid (ASA, 3.5-40 Units/L for heparin using a microfluidic device. We also measured complete blood counts (CBC and platelet activity using whole blood impedance aggregometry. Effects of shear rate and dose were analyzed using general linear models, logistic regressions, and Cox proportional hazards models. Shear rates have significant effects on thrombosis/dose-response curves for all tested therapies. ASA has little effect on high shear occlusion times, even at very high doses (up to 20 times the recommended dose. Under ASA therapy, thrombi formed at high shear rates were 4 times more prone to detachment compared to those formed under control conditions. Eptifibatide reduced occlusion when controlling for shear rate and its efficacy increased with dose concentration. In contrast, the hazard of occlusion from ASA was several orders of magnitude higher than that of eptifibatide. Our results show similar dose efficacy to our low shear measurements using whole blood aggregometry. This quantitative and statistically validated study of the effects of a wide range of shear rate and antiplatelet therapy doses on occlusive thrombosis contributes to more accurate understanding of thrombosis and to models for optimizing patient treatment.

  6. A Novel Geometry for Shear Test Using Axial Tensile Setup

    Directory of Open Access Journals (Sweden)

    Sibo Yuan

    2018-05-01

    Full Text Available This paper studies a novel geometry for the in-plane shear test performed with an axial electromechanical testing machine. In order to investigate the influence of the triaxiality rate on the mechanical behavior, different tests will be performed on the studied material: simple tensile tests, large tensile tests and shear tests. For the whole campaign, a common equipment should be employed to minimize the impact of the testing device. As a consequence, for the shear tests, the geometry of the specimen must be carefully designed in order to adapt the force value and make it comparable to the one obtained for the tensile tests. Like most of the existing shear-included tensile test specimens, the axial loading is converted to shear loading at a particular region through the effect of geometry. A symmetric shape is generally preferred, since it can restrict the in-plane rotation of the shear section, keep shear increasing in a more monotonic path and double the force level thanks to the two shear zones. Due to the specific experimental conditions, such as dimensions of the furnace and the clamping system, the position of the extensometer or the restriction of sheet thickness (related to the further studies of size effect at mesoscale and hot temperature, several geometries were brought up and evaluated in an iterative procedure via finite element simulations. Both the numerical and experimental results reveal that the final geometry ensures some advantages. For instance, a relatively low triaxiality in the shear zone, limited in-plane rotation and no necking are observed. Moreover, it also prevents any out-of-plane displacement of the specimen which seems to be highly sensitive to the geometry, and presents a very limited influence of the material and the thickness.

  7. In vivo wall shear measurements within the developing zebrafish heart.

    Directory of Open Access Journals (Sweden)

    R Aidan Jamison

    Full Text Available Physical forces can influence the embryonic development of many tissues. Within the cardiovascular system shear forces resulting from blood flow are known to be one of the regulatory signals that shape the developing heart. A key challenge in investigating the role of shear forces in cardiac development is the ability to obtain shear force measurements in vivo. Utilising the zebrafish model system we have developed a methodology that allows the shear force within the developing embryonic heart to be determined. Accurate wall shear measurement requires two essential pieces of information; high-resolution velocity measurements near the heart wall and the location and orientation of the heart wall itself. We have applied high-speed brightfield imaging to capture time-lapse series of blood flow within the beating heart between 3 and 6 days post-fertilization. Cardiac-phase filtering is applied to these time-lapse images to remove the heart wall and other slow moving structures leaving only the red blood cell movement. Using particle image velocimetry to calculate the velocity of red blood cells in different regions within the heart, and using the signal-to-noise ratio of the cardiac-phase filtered images to determine the boundary of blood flow, and therefore the position of the heart wall, we have been able to generate the necessary information to measure wall shear in vivo. We describe the methodology required to measure shear in vivo and the application of this technique to the developing zebrafish heart. We identify a reduction in shear at the ventricular-bulbar valve between 3 and 6 days post-fertilization and demonstrate that the shear environment of the ventricle during systole is constantly developing towards a more uniform level.

  8. In vivo wall shear measurements within the developing zebrafish heart.

    Science.gov (United States)

    Jamison, R Aidan; Samarage, Chaminda R; Bryson-Richardson, Robert J; Fouras, Andreas

    2013-01-01

    Physical forces can influence the embryonic development of many tissues. Within the cardiovascular system shear forces resulting from blood flow are known to be one of the regulatory signals that shape the developing heart. A key challenge in investigating the role of shear forces in cardiac development is the ability to obtain shear force measurements in vivo. Utilising the zebrafish model system we have developed a methodology that allows the shear force within the developing embryonic heart to be determined. Accurate wall shear measurement requires two essential pieces of information; high-resolution velocity measurements near the heart wall and the location and orientation of the heart wall itself. We have applied high-speed brightfield imaging to capture time-lapse series of blood flow within the beating heart between 3 and 6 days post-fertilization. Cardiac-phase filtering is applied to these time-lapse images to remove the heart wall and other slow moving structures leaving only the red blood cell movement. Using particle image velocimetry to calculate the velocity of red blood cells in different regions within the heart, and using the signal-to-noise ratio of the cardiac-phase filtered images to determine the boundary of blood flow, and therefore the position of the heart wall, we have been able to generate the necessary information to measure wall shear in vivo. We describe the methodology required to measure shear in vivo and the application of this technique to the developing zebrafish heart. We identify a reduction in shear at the ventricular-bulbar valve between 3 and 6 days post-fertilization and demonstrate that the shear environment of the ventricle during systole is constantly developing towards a more uniform level.

  9. Leaching Characteristics of Uranium And Copper from Their Mineralization in the Carbonate Rich latosol of Abu-Thor Locality, South Western Sinai, Egypt

    International Nuclear Information System (INIS)

    El-Sheikh, E.M.; Ghazala, R.A.; Abdelwarith, A.; Salem, F.; Ali, S.

    2015-01-01

    The chemical processing of the poly-mineralized carbonate rich latosol ore occurring at Abu-Thor locality of south western Sinai area has been studied for the recovery of uranium and copper metal values. A technological sample assaying 700 ppm U and 9.7% Cu was collected. In the present study, two successive percolation leaching procedures were performed after determination of optimum leaching factors by agitation leaching process. The first was carried out for uranium recovery by using urea as organic leaching agent which was possible to achieve leaching efficiency exceeding 90.3%. This procedure was followed by a second one for copper recovery using ammonium hydroxide solution and ammonium carbonate. The obtained dissolution efficiency was about 93%. The leached metal values namely U and Cu from the studied ore were then extracted as marketable products in the form of ammonium diuranate and copper sulphate, respectively.

  10. Shear-coupled grain-boundary migration dependence on normal strain/stress

    Science.gov (United States)

    Combe, N.; Mompiou, F.; Legros, M.

    2017-08-01

    In specific conditions, grain-boundary (GB) migration occurs in polycrystalline materials as an alternative vector of plasticity compared to the usual dislocation activity. The shear-coupled GB migration, the expected most efficient GB based mechanism, couples the GB motion to an applied shear stress. Stresses on GB in polycrystalline materials seldom have, however, a unique pure shear component. This work investigates the influence of a normal strain on the shear coupled migration of a Σ 13 (320 )[001 ] GB in a copper bicrystal using atomistic simulations. We show that the yield shear stress inducing the GB migration strongly depends on the applied normal stress. Beyond, the application of a normal stress on this GB qualitatively modifies the GB migration: while the Σ 13 (320 )[001 ] GB shear couples following the 〈110 〉 migration mode without normal stress, we report the observation of the 〈010 〉 mode under a sufficiently high tensile normal stress. Using the nudge elastic band method, we uncover the atomistic mechanism of this 〈010 〉 migration mode and energetically characterize it.

  11. Experimental Study on Shear Performance of Bolt in Roadway Supporting

    Directory of Open Access Journals (Sweden)

    D.J. Li

    2014-09-01

    Full Text Available The corner bolt is proved to be effective in the control of floor deformation of roadway, and the relevant studies on bolting mechanisms are of great significance in improving roadway stability. In this paper, two types of shear tests on six forms of bolts are performed by using self-designed shear test device, the electro-hydraulic servo triaxial testing system. The shear characteristics of different types of bolts are obtained. The results show that different bolt rods or different internal filling conditions result in large differences in shear resistance and different deformation adaptability. We find that the filling materials added can improve the shear performance of bolt significantly, and the bolt with steel not only can improve the strength of bolt body, but also has the bimodal characteristic that makes the bolt have the secondary bearing capacity and withstand larger deformation range during the process of shear, and shows a better support performance. Hoping to provide the experiment basis for support design and field application in the future.

  12. Drift Wave Test Particle Transport in Reversed Shear Profile

    International Nuclear Information System (INIS)

    Horton, W.; Park, H.B.; Kwon, J.M.; Stronzzi, D.; Morrison, P.J.; Choi, D.I.

    1998-01-01

    Drift wave maps, area preserving maps that describe the motion of charged particles in drift waves, are derived. The maps allow the integration of particle orbits on the long time scale needed to describe transport. Calculations using the drift wave maps show that dramatic improvement in the particle confinement, in the presence of a given level and spectrum of E x B turbulence, can occur for q(r)-profiles with reversed shear. A similar reduction in the transport, i.e. one that is independent of the turbulence, is observed in the presence of an equilibrium radial electric field with shear. The transport reduction, caused by the combined effects of radial electric field shear and both monotonic and reversed shear magnetic q-profiles, is also investigated

  13. Wind shear coefficients and their effect on energy production

    International Nuclear Information System (INIS)

    Rehman, Shafiqur; Al-Abbadi, Naif M.

    2005-01-01

    This paper provides realistic values of wind shear coefficients calculated using measured values of wind speed at 20, 30 and 40 m above the ground for the first time in Saudi Arabia in particular and, to the best of the authors' knowledge, in the Gulf region in general. The paper also presents air density values calculated using the measured air temperature and surface pressure and the effects of wind shear factor on energy production from wind machines of different sizes. The measured data used in the study covered a period of almost three years between June 17, 1995 and December 1998. An overall mean value of wind shear coefficient of 0.194 can be used with confidence to calculate the wind speed at different heights if measured values are known at one height. The study showed that the wind shear coefficient is significantly influenced by seasonal and diurnal changes. Hence, for precise estimations of wind speed at a height, both monthly or seasonal and hourly or night time and day time average values of wind shear coefficient must be used. It is suggested that the wind shear coefficients must be calculated either (i) using long term average values of wind speed at different heights or (ii) using those half hourly mean values of wind speed for which the wind shear coefficient lies in the range 0 and 0.51. The air density, calculated using measured temperature and pressure was found to be 1.18 kg/m 3 . The air density values were also found to vary with the season of the year and hour of the day, and hence, care must be taken when precise calculations are to be made. The air density values, as shown in this paper, have no significant variation with height. The energy production analysis showed that the actual wind shear coefficient presented in this paper produced 6% more energy compared to that obtained using the 1/7 power law. Similarly, higher plant capacity factors were obtained with the wind shear factor of 0.194 compared to that with 0.143

  14. Cargo Release from Polymeric Vesicles under Shear

    Directory of Open Access Journals (Sweden)

    Yingying Guo

    2018-03-01

    Full Text Available In this paper we study the release of cargo from polymeric nano-carriers under shear. Vesicles formed by two star block polymers— A 12 B 6 C 2 ( A B C and A 12 B 6 A 2 ( A B A —and one linear block copolymer— A 14 B 6 ( A B , are investigated using dissipative particle dynamics (DPD simulations. A - and C -blocks are solvophobic and B -block is solvophilic. The three polymers form vesicles of different structures. The vesicles are subjected to shear both in bulk and between solvophobic walls. In bulk shear, the mechanisms of cargo release are similar for all vesicles, with cargo travelling through vesicle membrane with no preferential release location. When sheared between walls, high cargo release rate is only observed with A B C vesicle after it touches the wall. For A B C vesicle, the critical condition for high cargo release rate is the formation of wall-polymersome interface after which the effect of shear rate in promoting cargo release is secondary. High release rate is achieved by the formation of solvophilic pathway allowing cargo to travel from the vesicle cavity to the vesicle exterior. The results in this paper show that well controlled target cargo release using polymersomes can be achieved with polymers of suitable design and can potentially be very useful for engineering applications. As an example, polymersomes can be used as carriers for surface active friction reducing additives which are only released at rubbing surfaces where the additives are needed most.

  15. Low-n shear Alfven spectra in axisymmetric toroidal plasmas

    International Nuclear Information System (INIS)

    Cheng, C.Z.; Chance, M.S.

    1985-11-01

    In toroidal plasmas, the toroidal magnetic field is nonuniform over a magnetic surface and causes coupling of different poloidal harmonics. It is shown both analytically and numerically that the toroidicity not only breaks up the shear Alfven continuous spectrum, but also creates new, discrete, toroidicity-induced shear Alfven eigenmodes with frequencies inside the continuum gaps. Potential applications of the low-n toroidicity-induced shear Alfven eigenmodes on plasma heating and instabilities are addressed. 17 refs., 4 figs

  16. Length and activation dependent variations in muscle shear wave speed

    International Nuclear Information System (INIS)

    Chernak, L A; DeWall, R J; Lee, K S; Thelen, D G

    2013-01-01

    Muscle stiffness is known to vary as a result of a variety of disease states, yet current clinical methods for quantifying muscle stiffness have limitations including cost and availability. We investigated the capability of shear wave elastography (SWE) to measure variations in gastrocnemius shear wave speed induced via active contraction and passive stretch. Ten healthy young adults were tested. Shear wave speeds were measured using a SWE transducer positioned over the medial gastrocnemius at ankle angles ranging from maximum dorsiflexion to maximum plantarflexion. Shear wave speeds were also measured during voluntary plantarflexor contractions at a fixed ankle angle. Average shear wave speed increased significantly from 2.6 to 5.6 m s –1 with passive dorsiflexion and the knee in an extended posture, but did not vary with dorsiflexion when the gastrocnemius was shortened in a flexed knee posture. During active contractions, shear wave speed monotonically varied with the net ankle moment generated, reaching 8.3 m s –1 in the maximally contracted condition. There was a linear correlation between shear wave speed and net ankle moment in both the active and passive conditions; however, the slope of this linear relationship was significantly steeper for the data collected during passive loading conditions. The results show that SWE is a promising approach for quantitatively assessing changes in mechanical muscle loading. However, the differential effect of active and passive loading on shear wave speed makes it important to carefully consider the relevant loading conditions in which to use SWE to characterize in vivo muscle properties. (paper)

  17. Development of a Skewed Pipe Shear Connector for Precast Concrete Structures.

    Science.gov (United States)

    Kim, Sang-Hyo; Choi, Jae-Gu; Park, Sejun; Lee, Hyunmin; Heo, And Won-Ho

    2017-05-13

    Joint connection methods, such as shear key and loop bar, improve the structural performance of precast concrete structures; consequently, there is usually decreased workability or constructional efficiency. This paper proposes a high-efficiency skewed pipe shear connector. To resist shear and pull-out forces, the proposed connectors are placed diagonally between precast concrete segments and a cast-in-place concrete joint part on a girder. Design variables (such as the pipe diameter, length, and insertion angle) have been examined to investigate the connection performance of the proposed connector. The results of our testing indicate that the skewed pipe shear connectors have 50% higher ductility and a 15% higher ratio of maximum load to yield strength as compared to the corresponding parameters of the loop bar. Finite element analysis was used for validation. The resulting validation indicates that, compared to the loop bar, the skewed pipe shear connector has a higher ultimate shear and pull-out resistance. These results indicate that the skewed pipe shear connector demonstrates more idealized behavior than the loop bar in precast concrete structures.

  18. Flow shear stabilization of hybrid electron-ion drift mode in tokamaks

    International Nuclear Information System (INIS)

    Bai, L.

    1999-01-01

    In this paper, a model of sheared flow stabilization on hybrid electron-ion drift mode is proposed. At first, in the presence of dissipative trapped electrons, there exists an intrinsic oscillation mode in tokamak plasmas, namely hybrid dissipative trapped electron-ion temperature gradient mode (hereafter, called as hybrid electron-ion drift mode). This conclusion is in agreement with the observations in the simulated tokamak experiment on the CLM. Then, it is found that the coupling between the sheared flows and dissipative trapped electrons is proposed as the stabilization mechanism of both toroidal sheared flow and poloidal sheared flow on the hybrid electron-ion drift mode, that is, similar to the stabilizing effect of poloidal sheared flow on edge plasmas in tokamaks, in the presence of both dissipative trapped electrons and toroidal sheared flow, large toroidal sheared flow is always a strong stabilizing effect on the hybrid electron-ion drift mode in internal transport barrier location, too. This result is consistent with the experimental observations in JT-60U. (author)

  19. Flow shear stabilization of hybrid electron-ion drift mode in tokamaks

    International Nuclear Information System (INIS)

    Bai, L.

    2001-01-01

    In this paper, a model of sheared flow stabilization on hybrid electron-ion drift mode is proposed. At first, in the presence of dissipative trapped electrons, there exists an intrinsic oscillation mode in tokamak plasmas, namely hybrid dissipative trapped electron-ion temperature gradient mode (hereafter, called as hybrid electron-ion drift mode). This conclusion is in agreement with the observations in the simulated tokamak experiment on the CLM. Then, it is found that the coupling between the sheared flows and dissipative trapped electrons is proposed as the stabilization mechanism of both toroidal sheared flow and poloidal sheared flow on the hybrid electron-ion drift mode, that is, similar to the stabilizing effect of poloidal sheared flow on edge plasmas in tokamaks, in the presence of both dissipative trapped electrons and toroidal sheared flow, large toroidal sheared flow is always a strong stabilizing effect on the hybrid electron-ion drift mode in internal transport barrier location, too. This result is consistent with the experimental observations in JT-60U. (author)

  20. Geological and structural characterization and microtectonic study of shear zones Colonia

    International Nuclear Information System (INIS)

    Gianotti, V.; Oyhantcabal, P.; Spoturno, J.; Wemmer, K.

    2010-01-01

    The “Colonia Shear Zone System”, characterized by a transcurrent system of predominant sinistral shear sense, is defined by two approximately parallel shear zones, denominated Isla San Gabriel-Juan Lacaze Shear Zone (ISG-JL S.Z.) and Islas de Hornos-Arroyo Riachuelo Shear Zone (IH-AºR S. Z.). Represented by rocks with ductile and brittle deformation, are defined as a strike slip fault system, with dominant subvertical foliation orientations: 090-100º (dip-direction 190º) and 090-100º (dip-direction 005º). The K/Ar geochronology realized, considering the estimates temperatures conditions for shear zones (450-550º), indicate that 1780-1812 Ma should be considered a cooling age and therefore a minimum deformation age. The observed microstructures suggest deformation conditions with temperatures between 450-550º overprinted by cataclastic flow structures (reactivation at lower temperature)

  1. A study on plate anchor detailing systems of shear re-bar

    International Nuclear Information System (INIS)

    Tsurumaki, S.; Ujiie, K.; Nishikawa, T.; Kitayama, K.

    1995-01-01

    For shell walls and base slabs in reactor buildings, besides a large amount of main bars, numerous shear re-bars have been employed to resist to out-of-plane force. As a result , detailing work involving shear re-bar is extremely involved. For example, the employed re-bar anchor method differs from the ordinary methods in which, a end of shear re-bar with 135-degrees hook or with anchor plate type and another re-bar end with 90-degrees hook are used. However the structural characteristics in members using shear re-bar of the bolt-mounted anchor plate have not yet been examined. A test was performed to confirm the effects of anchor methods for shear re-bars on shearing behavior of members. This paper describes the test plan, method and results. (author). 12 figs., 7 tabs

  2. Structure-rheology relationship in a sheared lamellar fluid.

    Science.gov (United States)

    Jaju, S J; Kumaran, V

    2016-03-01

    The structure-rheology relationship in the shear alignment of a lamellar fluid is studied using a mesoscale model which provides access to the lamellar configurations and the rheology. Based on the equations and free energy functional, the complete set of dimensionless groups that characterize the system are the Reynolds number (ργL(2)/μ), the Schmidt number (μ/ρD), the Ericksen number (μγ/B), the interface sharpness parameter r, the ratio of the viscosities of the hydrophilic and hydrophobic parts μ(r), and the ratio of the system size and layer spacing (L/λ). Here, ρ and μ are the fluid density and average viscosity, γ is the applied strain rate, D is the coefficient of diffusion, B is the compression modulus, μ(r) is the maximum difference in the viscosity of the hydrophilic and hydrophobic parts divided by the average viscosity, and L is the system size in the cross-stream direction. The lattice Boltzmann method is used to solve the concentration and momentum equations for a two dimensional system of moderate size (L/λ=32) and for a low Reynolds number, and the other parameters are systematically varied to examine the qualitative features of the structure and viscosity evolution in different regimes. At low Schmidt numbers where mass diffusion is faster than momentum diffusion, there is fast local formation of randomly aligned domains with "grain boundaries," which are rotated by the shear flow to align along the extensional axis as time increases. This configuration offers a high resistance to flow, and the layers do not align in the flow direction even after 1000 strain units, resulting in a viscosity higher than that for an aligned lamellar phase. At high Schmidt numbers where momentum diffusion is fast, the shear flow disrupts layers before they are fully formed by diffusion, and alignment takes place by the breakage and reformation of layers by shear, resulting in defects (edge dislocations) embedded in a background of nearly aligned layers

  3. Simulation of shear and turbulence impact on wind turbine performance

    DEFF Research Database (Denmark)

    Wagner, Rozenn; Courtney, Michael; Larsen, Torben J.

    Aerodynamic simulations (HAWC2Aero) were used to investigate the influence of the speed shear, the direction shear and the turbulence intensity on the power output of a multi-megawatt turbine. First simulation cases with laminar flow and power law wind speed profiles were compared to the case...... of a uniform inflow. Secondly, a similar analysis was done for cases with direction shear. In each case, we derived a standard power curve (function of the wind speed at hub height) and power curves obtained with various definitions of equivalent wind speed in order to reduce the scatter due to shear. Thirdly...

  4. Shear Capacity of Large-Scale RC Beams Affected by ASR

    DEFF Research Database (Denmark)

    Gustenhoff Hansen, Søren; Barbosa, Ricardo Antonio; Hoang, Linh Cao

    2016-01-01

    This paper deals with the influence of alkali-silica reaction (ASR) on the shear capacity for concrete slabs without shear reinforcement. An experimental full-scale in-situ program consisting of four slabs from a bridge (Vosnæsvej) has been carried out and the results have been published in ref. [1......) and Eurocode 2 (EN 1992-1-1). The analysis shows that three experiments were highly affected by the preparation of the experimental setup. Only one experiment contained useful information about the shear capacity. The analysis of this experiment shows that the shear capacity is not reduced as much...

  5. Shear Wave Generation by Decoupled and Partially Coupled Explosions

    National Research Council Canada - National Science Library

    Stevens, Jeffry L; Xu, Heming; Baker, G. E

    2008-01-01

    The objective of this project is to investigate the sources of shear wave generation by decoupled and partially coupled explosions, and the differences in shear wave generation between tamped and decoupled explosions...

  6. Shear viscosity enhancement in water–nanoparticle suspensions

    International Nuclear Information System (INIS)

    Balasubramanian, Ganesh; Sen, Swarnendu; Puri, Ishwar K.

    2012-01-01

    Equilibrium molecular dynamics simulations characterize the increase in the shear viscosity of water around a suspended silicon dioxide nanoparticle. Water layering on the solid surface decreases the fraction of adjacent fluid molecules that are more mobile and hence less viscous, thereby increasing the shear viscosity. The contribution of the nanoparticle surface area to this rheological behavior is identified and an empirical model that accounts for it is provided. The model successfully reproduces the shear viscosity predictions from previous experimental measurements as well as our simulations. -- Highlights: ► Layering of water on the solid surfaces increases the fraction of less mobile molecules adjacent to them. ► A nondimensional parameter predicts of viscosity enhancement due to particle shape, volume fraction. ► Model predictions agree with the results of atomistic simulations and experimental measurements.

  7. Shear-driven phase transformation in silicon nanowires.

    Science.gov (United States)

    Vincent, L; Djomani, D; Fakfakh, M; Renard, C; Belier, B; Bouchier, D; Patriarche, G

    2018-03-23

    We report on an unprecedented formation of allotrope heterostructured Si nanowires by plastic deformation based on applied radial compressive stresses inside a surrounding matrix. Si nanowires with a standard diamond structure (3C) undergo a phase transformation toward the hexagonal 2H-allotrope. The transformation is thermally activated above 500 °C and is clearly driven by a shear-stress relief occurring in parallel shear bands lying on {115} planes. We have studied the influence of temperature and axial orientation of nanowires. The observations are consistent with a martensitic phase transformation, but the finding leads to clear evidence of a different mechanism of deformation-induced phase transformation in Si nanowires with respect to their bulk counterpart. Our process provides a route to study shear-driven phase transformation at the nanoscale in Si.

  8. Shear layer characteristics of supersonic free and impinging jets

    Science.gov (United States)

    Davis, T. B.; Kumar, R.

    2015-09-01

    The initial shear layer characteristics of a jet play an important role in the initiation and development of instabilities and hence radiated noise. Particle image velocimetry has been utilized to study the initial shear layer development of supersonic free and impinging jets. Microjet control employed to reduce flow unsteadiness and jet noise appears to affect the development of the shear layer, particularly near the nozzle exit. Velocity field measurements near the nozzle exit show that the initially thin, uncontrolled shear layer develops at a constant rate while microjet control is characterized by a rapid nonlinear thickening that asymptotes downstream. The shear layer linear growth rate with microjet control, in both the free and the impinging jet, is diminished. In addition, the thickened shear layer with control leads to a reduction in azimuthal vorticity for both free and impinging jets. Linear stability theory is used to compute unstable growth rates and convection velocities of the resultant velocity profiles. The results show that while the convection velocity is largely unaffected, the unstable growth rates are significantly reduced over all frequencies with microjet injection. For the case of the impinging jet, microjet control leads to near elimination of the impingement tones and an appreciable reduction in broadband levels. Similarly, for the free jet, significant reduction in overall sound pressure levels in the peak radiation direction is observed.

  9. Shear-limited test particle diffusion in 2-dimensional plasmas

    International Nuclear Information System (INIS)

    Anderegg, Francois; Driscoll, C. Fred; Dubin, Daniel H.E.

    2002-01-01

    Measurements of test-particle diffusion in pure ion plasmas show 2D enhancements over the 3D rates, limited by shear in the plasma rotation ω E (r). The diffusion is due to 'long-range' ion-ion collisions in the quiescent, steady-state Mg + plasma. For short plasma length L p and low shear S≡r∂ω E /∂r, thermal ions bounce axially many times before shear separates them in θ, so the ions move in (r,θ) as bounce averaged 'rods' of charge (i.e. 2D point vortices). Experimentally, we vary the number of bounces over the range 0.2≤N b ≤10,000. For long plasmas with N b ≤1, we observe diffusion in quantitative agreement with the 3D theory of long-range ExB drift collisions. For shorter plasmas or lower shear, with N b >1, we measure diffusion rates enhanced by up to 100x. For exceedingly small she0ar, i.e. N b ≥1000, we observe diffusion rates consistent with the Taylor-McNamara estimates for a shear-free thermal plasma. Overall, the data shows fair agreement with Dubin's new theory of 2D diffusion in shear, which predicts an enhancement of D 2D /D 3D ≅N b up to the Taylor-McNamara limit

  10. A sensitive dynamic viscometer for measuring the complex shear modulus in a steady shear flow using the method of orthogonal superposition

    NARCIS (Netherlands)

    Zeegers, J.C.H.; Zeegers, Jos; van den Ende, Henricus T.M.; Blom, C.; Altena, E.G.; Beukema, Gerrit J.; Beukema, G.J.; Mellema, J.

    1995-01-01

    A new instrument to carry out complex viscosity measurements in equilibrium and in a steady shear flow has been developed. A small amplitude harmonic excitation is superimposed orthogonally to the steady shear rate component. It is realized by a thin-walled cylinder, which oscillates in the axial

  11. Interfacial Shear Strength and Adhesive Behavior of Silk Ionomer Surfaces.

    Science.gov (United States)

    Kim, Sunghan; Geryak, Ren D; Zhang, Shuaidi; Ma, Ruilong; Calabrese, Rossella; Kaplan, David L; Tsukruk, Vladimir V

    2017-09-11

    The interfacial shear strength between different layers in multilayered structures of layer-by-layer (LbL) microcapsules is a crucial mechanical property to ensure their robustness. In this work, we investigated the interfacial shear strength of modified silk fibroin ionomers utilized in LbL shells, an ionic-cationic pair with complementary ionic pairing, (SF)-poly-l-glutamic acid (Glu) and SF-poly-l-lysine (Lys), and a complementary pair with partially screened Coulombic interactions due to the presence of poly(ethylene glycol) (PEG) segments and SF-Glu/SF-Lys[PEG] pair. Shearing and adhesive behavior between these silk ionomer surfaces in the swollen state were probed at different spatial scales and pressure ranges by using functionalized atomic force microscopy (AFM) tips as well as functionalized colloidal probes. The results show that both approaches were consistent in analyzing the interfacial shear strength of LbL silk ionomers at different spatial scales from a nanoscale to a fraction of a micron. Surprisingly, the interfacial shear strength between SF-Glu and SF-Lys[PEG] pair with partially screened ionic pairing was greater than the interfacial shear strength of the SF-Glu and SF-Lys pair with a high density of complementary ionic groups. The difference in interfacial shear strength and adhesive strength is suggested to be predominantly facilitated by the interlayer hydrogen bonding of complementary amino acids and overlap of highly swollen PEG segments.

  12. NUMERICAL SIMULATION OF AN AGRICULTURAL SOIL SHEAR STRESS TEST

    Directory of Open Access Journals (Sweden)

    Andrea Formato

    2007-03-01

    Full Text Available In this work a numerical simulation of agricultural soil shear stress tests was performed through soil shear strength data detected by a soil shearometer. We used a soil shearometer available on the market to measure soil shear stress and constructed special equipment that enabled automated detection of soil shear stress. It was connected to an acquisition data system that displayed and recorded soil shear stress during the full field tests. A soil shearometer unit was used to the in situ measurements of soil shear stress in full field conditions for different types of soils located on the right side of the Sele river, at a distance of about 1 km from each other, along the perpendicular to the Sele river in the direction of the sea. Full field tests using the shearometer unit were performed alongside considered soil characteristic parameter data collection. These parameter values derived from hydrostatic compression and triaxial tests performed on considered soil samples and repeated 4 times and we noticed that the difference between the maximum and minimum values detected for every set of performed tests never exceeded 4%. Full field shear tests were simulated by the Abaqus program code considering three different material models of soils normally used in the literature, the Mohr-Coulomb, Drucker-Prager and Cam-Clay models. We then compared all data outcomes obtained by numerical simulations with those from the experimental tests. We also discussed any further simulation data results obtained with different material models and selected the best material model for each considered soil to be used in tyre/soil contact simulation or in soil compaction studies.

  13. Shear-Rate-Dependent Behavior of Clayey Bimaterial Interfaces at Landslide Stress Levels

    Science.gov (United States)

    Scaringi, Gianvito; Hu, Wei; Xu, Qiang; Huang, Runqiu

    2018-01-01

    The behavior of reactivated and first-failure landslides after large displacements is controlled by the available shear resistance in a shear zone and/or along slip surfaces, such as a soil-bedrock interface. Among the factors influencing the resistance parameter, the dependence on the shear rate can trigger catastrophic evolution (rate-weakening) or exert a slow-down feedback (rate-strengthening) upon stress perturbation. We present ring-shear test results, performed under various normal stresses and shear rates, on clayey soils from a landslide shear zone, on its parent lithology and other lithologies, and on clay-rock interface samples. We find that depending on the materials in contact, the normal stress, and the stress history, the shear-rate-dependent behaviors differ. We discuss possible models and underlying mechanisms for the time-dependent behavior of landslides in clay soils.

  14. Inplane shear capacity of reinforced composite masonry block walls

    International Nuclear Information System (INIS)

    White, W.H.; Tseng, W.S.

    1981-01-01

    The objective of this paper is to describe a test program performed to determine the inplane shear capacity, stiffness and ductility of composite masonry walls subjected to earthquake type loadings. Specimens were simultaneously subjected to a range of compressive loads to simulate dead load; and inplane shear loads with full load reversal to simulate the earthquake cycling load. The influence of horizontal and vertical reinforcing steel percentages on the inplane shear capacity, stiffness and ductility was also investigated. (orig./HP)

  15. Coherent structures in compressible free-shear-layer flows

    Energy Technology Data Exchange (ETDEWEB)

    Aeschliman, D.P.; Baty, R.S. [Sandia National Labs., Albuquerque, NM (United States). Engineering Sciences Center; Kennedy, C.A.; Chen, J.H. [Sandia National Labs., Livermore, CA (United States). Combustion and Physical Sciences Center

    1997-08-01

    Large scale coherent structures are intrinsic fluid mechanical characteristics of all free-shear flows, from incompressible to compressible, and laminar to fully turbulent. These quasi-periodic fluid structures, eddies of size comparable to the thickness of the shear layer, dominate the mixing process at the free-shear interface. As a result, large scale coherent structures greatly influence the operation and efficiency of many important commercial and defense technologies. Large scale coherent structures have been studied here in a research program that combines a synergistic blend of experiment, direct numerical simulation, and analysis. This report summarizes the work completed for this Sandia Laboratory-Directed Research and Development (LDRD) project.

  16. Bed shear stress distribution in straight channels with arbitrary cross section

    DEFF Research Database (Denmark)

    Christensen, Henrik Bo; Fredsøe, Jørgen

    1998-01-01

    The bed shear stress distribution in straight open channels is affected by mechanisms as bed curvature of the cross section profile, shear diffusion, and secondary currents. This paper compares some analytical and numerical methods to estimate the bed shear stress distribution. The methods...

  17. Effects of cyclic shear loads on strength, stiffness and dilation of rock fractures

    Directory of Open Access Journals (Sweden)

    Thanakorn Kamonphet

    2015-12-01

    Full Text Available Direct shear tests have been performed to determine the peak and residual shear strengths of fractures in sandstone, granite and limestone under cyclic shear loading. The fractures are artificially made in the laboratory by tension inducing and saw-cut methods. Results indicate that the cyclic shear load can significantly reduce the fracture shear strengths and stiffness. The peak shear strengths rapidly decrease after the first cycle and tend to remain unchanged close to the residual strengths through the tenth cycle. Degradation of the first order asperities largely occurs after the first cycle. The fracture dilation rates gradually decrease from the first through the tenth cycles suggesting that the second order asperities continuously degrade after the first load cycle. The residual shear strengths are lower than the peak shear strengths and higher than those of the smooth fractures. The strength of smooth fracture tends to be independent of cyclic shear loading.

  18. Wind Shear Systems Implementation Plan, Benefit/Cost Study.

    Science.gov (United States)

    1980-08-01

    not. Accordingly, the three self contained Wind Shear Systems currently being marketed by avionics manufacturers are considered to have lower relative... RESEARC { AND I’iVEIOPMEN1 The FAA research ni d development ffort has taken a threefold appro,,ch to the vind sh#ear problem. Ore. approach was to

  19. Design proposal for ultimate shear strength of tapered steel plate girders

    Directory of Open Access Journals (Sweden)

    A. Bedynek

    2017-03-01

    Full Text Available Numerous experimental and numerical studies on prismatic plate girders subjected to shear can be found in the literature. However, the real structures are frequently designed as non-uniform structural elements. The main objective of the research is the development of a new proposal for the calculation of the ultimate shear resistance of tapered steel plate girders taking into account the specific behaviour of such members. A new mechanical model is presented in the paper and it is used to show the differences between the behaviour of uniform and tapered web panels subjected to shear. EN 1993-1-5 design specifications for the determination of the shear strength for rectangular plates are improved in order to assess the shear strength of tapered elements. Numerical studies carried out on tapered steel plate girders subjected to shear lead to confirm the suitability of the mechanical model and the proposed design expression.

  20. Double-Lap Shear Test For Honeycomb Core

    Science.gov (United States)

    Nettles, Alan T.; Hodge, Andrew J.

    1992-01-01

    Double-lap test measures shear strength of panel made of honeycomb core with 8-ply carbon-fiber/epoxy face sheets. Developed to overcome three principal disadvantages of prior standard single-lap shear test: specimen had to be more than 17 in. long; metal face sheets had to be used; and test introduced torque, with consequent bending and peeling of face sheets and spurious tensile or compressive loading of honeycomb.

  1. A simple model to understand the role of membrane shear elasticity and stress-free shape on the motion of red blood cells in shear flow

    Science.gov (United States)

    Viallat, Annie; Abkarian, Manouk; Dupire, Jules

    2015-11-01

    The analytical model presented by Keller and Skalak on the dynamics of red blood cells in shear flow described the cell as a fluid ellipsoid of fixed shape. It was extended to introduce shear elasticity of the cell membrane. We further extend the model when the cell discoid physiological shape is not a stress-free shape. We show that spheroid stress-free shapes enables fitting experimental data with values of shear elasticity typical to that found with micropipettes and optical tweezers. For moderate shear rates (when RBCs keep their discoid shape) this model enables to quantitatively determine an effective cell viscosity, that combines membrane and hemoglobin viscosities and an effective shear modulus of the membrane that combines shear modulus and stress-free shape. This model allows determining RBC mechanical parameters both in the tanktreading regime for cells suspended in a high viscosity medium, and in the tumbling regime for cells suspended in a low viscosity medium. In this regime,a transition is predicted between a rigid-like tumbling motion and a fluid-like tumbling motion above a critical shear rate, which is directly related to the mechanical parameters of the cell. A*MIDEX (n ANR-11-IDEX-0001-02) funded by the ''Investissements d'Avenir'', Region Languedoc-Roussillon, Labex NUMEV (ANR-10-LABX-20), BPI France project DataDiag.

  2. Multivariate Linear Regression and CART Regression Analysis of TBM Performance at Abu Hamour Phase-I Tunnel

    Science.gov (United States)

    Jakubowski, J.; Stypulkowski, J. B.; Bernardeau, F. G.

    2017-12-01

    The first phase of the Abu Hamour drainage and storm tunnel was completed in early 2017. The 9.5 km long, 3.7 m diameter tunnel was excavated with two Earth Pressure Balance (EPB) Tunnel Boring Machines from Herrenknecht. TBM operation processes were monitored and recorded by Data Acquisition and Evaluation System. The authors coupled collected TBM drive data with available information on rock mass properties, cleansed, completed with secondary variables and aggregated by weeks and shifts. Correlations and descriptive statistics charts were examined. Multivariate Linear Regression and CART regression tree models linking TBM penetration rate (PR), penetration per revolution (PPR) and field penetration index (FPI) with TBM operational and geotechnical characteristics were performed for the conditions of the weak/soft rock of Doha. Both regression methods are interpretable and the data were screened with different computational approaches allowing enriched insight. The primary goal of the analysis was to investigate empirical relations between multiple explanatory and responding variables, to search for best subsets of explanatory variables and to evaluate the strength of linear and non-linear relations. For each of the penetration indices, a predictive model coupling both regression methods was built and validated. The resultant models appeared to be stronger than constituent ones and indicated an opportunity for more accurate and robust TBM performance predictions.

  3. Stress relaxation of shear in metals during shock loading

    International Nuclear Information System (INIS)

    Glazyrin, V.P.; Platova, T.M.

    1988-01-01

    Constructed determining equation, taking into account stress relaxation of shear, was used to calculate the evolution of plane shock waves of primary and secondary compression in metals. Values of shear stress and viscosity coefficient were

  4. Effect of shear stress on the migration of hepatic stellate cells.

    Science.gov (United States)

    Sera, Toshihiro; Sumii, Tateki; Fujita, Ryosuke; Kudo, Susumu

    2018-01-01

    When the liver is damaged, hepatic stellate cells (HSCs) can change into an activated, highly migratory state. The migration of HSCs may be affected by shear stress due not only to sinusoidal flow but also by the flow in the space of Disse because this space is filled with blood plasma. In this study, we evaluated the effects of shear stress on HSC migration in a scratch-wound assay with a parallel flow chamber. At regions upstream of the wound area, the migration was inhibited by 0.6 Pa and promoted by 2.0 Pa shear stress, compared to the static condition. The platelet-derived growth factor (PDGF)-BB receptor, PDGFR-β, was expressed in all conditions and the differences were not significant. PDGF increased HSC migration, except at 0.6 Pa shear stress, which was still inhibited. These results indicate that another molecular factor, such as PDGFR-α, may act to inhibit the migration under low shear stress. At regions downstream of the wound area, the migration was smaller under shear stress than under the static condition, although the expression of PDGFR-β was significantly higher. In particular, the migration direction was opposite to the wound area under high shear stress; therefore, migration might be influenced by the intercellular environment. Our results indicate that HSC migration was influenced by shear stress intensity and the intercellular environment.

  5. Influence of Equilibrium Perpendicular Shear Flow on Peeling-ballooning Instabilities

    Science.gov (United States)

    Xi, P. W.; Xu, X. Q.

    2011-10-01

    The influence of perpendicular ExB shear flow on peeling-ballooning instabilities is investigated with BOUT++ code. In our simulation, a set of reduced MHD equations are solved for a very unstable equilibrium and a marginal unstable equilibrium in shifted-circular tokamak geometry. For ideal MHD cases without diamagnetic terms and resistivity, we find that flow shear shows dramatic stabilizing effect on peeling-ballooning modes and the stabilizing degree increases with mode number. When the flow shear is large enough, we find the curvature of growth rate verse mode number has the same shape like that for the case with only diamagnetic term, and this implies that diamagnetic term and the shear flow have the same mechanism acting on peeling-ballooning instabilities. The role of Kelvin-Helmholtz term is also investigated and we find it is destabilizing and the effect depends on both flow shear and mode number. For cases with both diamagnetic term and the applied shear flow, modes with intermediate mode number are strongest stabilized while high n and low n mode keep unstable. Based on these results, an ELM trigger sketch is proposed. Performed for USDoE by LLNL Contract DE-AC52-07NA27344.

  6. Compressibility effects in the shear layer over a rectangular cavity

    Energy Technology Data Exchange (ETDEWEB)

    Beresh, Steven J.; Wagner, Justin; Casper, Katya Marie

    2016-10-26

    we studied the influence of compressibility on the shear layer over a rectangular cavity of variable width in a free stream Mach number range of 0.6–2.5 using particle image velocimetry data in the streamwise centre plane. As the Mach number increases, the vertical component of the turbulence intensity diminishes modestly in the widest cavity, but the two narrower cavities show a more substantial drop in all three components as well as the turbulent shear stress. Furthermore, this contrasts with canonical free shear layers, which show significant reductions in only the vertical component and the turbulent shear stress due to compressibility. The vorticity thickness of the cavity shear layer grows rapidly as it initially develops, then transitions to a slower growth rate once its instability saturates. When normalized by their estimated incompressible values, the growth rates prior to saturation display the classic compressibility effect of suppression as the convective Mach number rises, in excellent agreement with comparable free shear layer data. The specific trend of the reduction in growth rate due to compressibility is modified by the cavity width.

  7. Reversed magnetic shear suppression of electron-scale turbulence on NSTX

    Science.gov (United States)

    Yuh, Howard Y.; Levinton, F. M.; Bell, R. E.; Hosea, J. C.; Kaye, S. M.; Leblanc, B. P.; Mazzucato, E.; Smith, D. R.; Domier, C. W.; Luhmann, N. C.; Park, H. K.

    2009-11-01

    Electron thermal internal transport barriers (e-ITBs) are observed in reversed (negative) magnetic shear NSTX discharges^1. These e-ITBs can be created with either neutral beam heating or High Harmonic Fast Wave (HHFW) RF heating. The e-ITB location occurs at the location of minimum magnetic shear determined by Motional Stark Effect (MSE) constrained equilibria. Statistical studies show a threshold condition in magnetic shear for e-ITB formation. High-k fluctuation measurements at electron turbulence wavenumbers^3 have been made under several different transport regimes, including a bursty regime that limits temperature gradients at intermediate magnetic shear. The growth rate of fluctuations has been calculated immediately following a change in the local magnetic shear, resulting in electron temperature gradient relaxation. Linear gyrokinetic simulation results for NSTX show that while measured electron temperature gradients exceed critical linear thresholds for ETG instability, growth rates can remain low under reversed shear conditions up to high electron temperatures gradients. ^1H. Yuh, et. al., PoP 16, 056120 ^2D.R. Smith, E. Mazzucato et al., RSI 75, 3840 ^3E. Mazzucato, D.R. Smith et al., PRL 101, 075001

  8. Shear waves in inhomogeneous, compressible fluids in a gravity field.

    Science.gov (United States)

    Godin, Oleg A

    2014-03-01

    While elastic solids support compressional and shear waves, waves in ideal compressible fluids are usually thought of as compressional waves. Here, a class of acoustic-gravity waves is studied in which the dilatation is identically zero, and the pressure and density remain constant in each fluid particle. These shear waves are described by an exact analytic solution of linearized hydrodynamics equations in inhomogeneous, quiescent, inviscid, compressible fluids with piecewise continuous parameters in a uniform gravity field. It is demonstrated that the shear acoustic-gravity waves also can be supported by moving fluids as well as quiescent, viscous fluids with and without thermal conductivity. Excitation of a shear-wave normal mode by a point source and the normal mode distortion in realistic environmental models are considered. The shear acoustic-gravity waves are likely to play a significant role in coupling wave processes in the ocean and atmosphere.

  9. Coexistence and transition between shear zones in slow granular flows.

    Science.gov (United States)

    Moosavi, Robabeh; Shaebani, M Reza; Maleki, Maniya; Török, János; Wolf, Dietrich E; Losert, Wolfgang

    2013-10-04

    We report experiments on slow granular flows in a split-bottom Couette cell that show novel strain localization features. Nontrivial flow profiles have been observed which are shown to be the consequence of simultaneous formation of shear zones in the bulk and at the boundaries. The fluctuating band model based on a minimization principle can be fitted to the experiments over a large variation of morphology and filling height with one single fit parameter, the relative friction coefficient μ(rel) between wall and bulk. The possibility of multiple shear zone formation is controlled by μ(rel). Moreover, we observe that the symmetry of an initial state, with coexisting shear zones at both side walls, breaks spontaneously below a threshold value of the shear velocity. A dynamical transition between two asymmetric flow states happens over a characteristic time scale which depends on the shear strength.

  10. Shear Driven Synthesis of Polymeric Micro- and Nanomaterials

    Science.gov (United States)

    Tian, Tian

    Polymeric micro- and nanomaterials play a significant role in various current and emerging technologies. A liquid shear based method was developed to fabricate a wide range of polymeric materials, which include fibers, sheets, ribbons, rods and spheres in a scalable, cost-effective and simple way. During the process, droplet shearing, droplet deformation, droplet breaking up and polymer precipitation occur simultaneously. The size and morphology of the resultant structures are determined by the dominating process which is further controlled by the experimental parameters including polymer concentration, polymer molecular weight and antisolvent concentration. Among all of these structures, nanofibers have attracted the latest research interest due to the unique properties. Current leading fiber production approaches in the market possess certain drawbacks. For example, the throughput of electrospinning is limited to around 2.5 kg/hr and the diameter of fiber produced by wet spinning cannot be below micrometer while melt spinning is only applicable to melt-processable polymers. The breakthrough of our liquid shear driven technique for fiber synthesis is that it produces fibers with diameter from 200 nm to several micrometers from a wide range of liquid- processable polymers with high commercial yield (up to 12 kg/hr). Thus in Chapter 2, the optimum parameters range for fiber formation is established and the effects of those parameters on fiber size are investigated. In the original liquid shear method, medium with high viscosity is needed to exert strong shear stress on the droplet and to stretch the droplets to long strand. However, the viscous medium complicates the post sample washing procedure and introduces the potential slippery danger in the working area. Thus a non-viscous medium shearing method is developed in Chapter 3 and it is the first time proposed that the synthesis of PLA or PS nanofibers can be completed in the aqueous ethanol medium. Colloid science

  11. Spurious Shear in Weak Lensing with LSST

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.; Kahn, S.M.; Jernigan, J.G.; Peterson, J.R.; AlSayyad, Y.; Ahmad, Z.; Bankert, J.; Bard, D.; Connolly, A.; Gibson, R.R.; Gilmore, K.; Grace, E.; Hannel, M.; Hodge, M.A.; Jee, M.J.; Jones, L.; Krughoff, S.; Lorenz, S.; Marshall, P.J.; Marshall, S.; Meert, A.

    2012-09-19

    The complete 10-year survey from the Large Synoptic Survey Telescope (LSST) will image {approx} 20,000 square degrees of sky in six filter bands every few nights, bringing the final survey depth to r {approx} 27.5, with over 4 billion well measured galaxies. To take full advantage of this unprecedented statistical power, the systematic errors associated with weak lensing measurements need to be controlled to a level similar to the statistical errors. This work is the first attempt to quantitatively estimate the absolute level and statistical properties of the systematic errors on weak lensing shear measurements due to the most important physical effects in the LSST system via high fidelity ray-tracing simulations. We identify and isolate the different sources of algorithm-independent, additive systematic errors on shear measurements for LSST and predict their impact on the final cosmic shear measurements using conventional weak lensing analysis techniques. We find that the main source of the errors comes from an inability to adequately characterise the atmospheric point spread function (PSF) due to its high frequency spatial variation on angular scales smaller than {approx} 10{prime} in the single short exposures, which propagates into a spurious shear correlation function at the 10{sup -4}-10{sup -3} level on these scales. With the large multi-epoch dataset that will be acquired by LSST, the stochastic errors average out, bringing the final spurious shear correlation function to a level very close to the statistical errors. Our results imply that the cosmological constraints from LSST will not be severely limited by these algorithm-independent, additive systematic effects.

  12. Experimental testing of hold down devices for timber frame shear walls

    OpenAIRE

    Caprolu, Giuseppe

    2012-01-01

    Källsner and Girhammar [1] have presented a new plastic design method for wood-framed shear walls at ultimate limit state. This method allows the designer to calculate the load-carrying capacity of partially anchored shear walls, where the leading stud is not anchored against uplift. The anchorage system of shear walls is provided by anchor bolts in the bottom rail and hold downs at the leading stud. Anchor bolts provide horizontal shear continuity between the bottom rail and the foundation. ...

  13. Shear of ordinary and elongated granular mixtures

    Science.gov (United States)

    Hensley, Alexander; Kern, Matthew; Marschall, Theodore; Teitel, Stephen; Franklin, Scott

    2015-03-01

    We present an experimental and computational study of a mixture of discs and moderate aspect-ratio ellipses under two-dimensional annular planar Couette shear. Experimental particles are cut from acrylic sheet, are essentially incompressible, and constrained in the thin gap between two concentric cylinders. The annular radius of curvature is much larger than the particles, and so the experiment is quasi-2d and allows for arbitrarily large pure-shear strains. Synchronized video cameras and software identify all particles and track them as they move from the field of view of one camera to another. We are particularly interested in the global and local properties as the mixture ratio of discs to ellipses varies. Global quantities include average shear rate and distribution of particle species as functions of height, while locally we investigate the orientation of the ellipses and non-affine events that can be characterized as shear transformational zones or possess a quadrupole signature observed previously in systems of purely circular particles. Discrete Element Method simulations on mixtures of circles and spherocylinders extend the study to the dynamics of the force network and energy dissipated as the system evolves. Supported by NSF CBET #1243571 and PRF #51438-UR10.

  14. Numerical modeling of shear stimulation in naturally fractured geothermal reservoirs

    OpenAIRE

    Ucar, Eren

    2018-01-01

    Shear-dilation-based hydraulic stimulations are conducted to create enhanced geothermal systems (EGS) from low permeable geothermal reservoirs, which are initially not amenable to energy production. Reservoir stimulations are done by injecting low-pressurized fluid into the naturally fractured formations. The injection aims to activate critically stressed fractures by decreasing frictional strength and ultimately cause a shear failure. The shear failure leads to a permanent ...

  15. Study on reinforced lightweight coconut shell concrete beam behavior under shear

    International Nuclear Information System (INIS)

    Gunasekaran, K.; Annadurai, R.; Kumar, P.S.

    2013-01-01

    Highlights: • Coconut shell used as aggregate in concrete production. • Coconut shell concrete beam behavior studied under shear. • Coconut shell concrete beam behavior are compared with control concrete beams. - Abstract: Lightweight concrete has been produced using crushed coconut shell as coarse aggregate. The shear behavior of reinforced concrete beam made with coconut shell is analyzed and compared with the normal control concrete. Eight beams, four with coconut shell concrete and four with normal control concrete were fabricated and tested. Study includes the structural shear behavior, shear capacity, cracking behavior, deflection behavior, ductility, strains in concrete and in reinforcement. It was observed that the shear behavior of coconut shell concrete is comparable to that of other lightweight concretes. The results of concrete compression strain and steel tension strain showed that coconut shell concrete is able to achieve its full strain capacity under shear loadings. However, the failure zones of coconut shell concrete were larger than for control concrete beams

  16. Cosmic Shear With ACS Pure Parallels

    Science.gov (United States)

    Rhodes, Jason

    2002-07-01

    Small distortions in the shapes of background galaxies by foreground mass provide a powerful method of directly measuring the amount and distribution of dark matter. Several groups have recently detected this weak lensing by large-scale structure, also called cosmic shear. The high resolution and sensitivity of HST/ACS provide a unique opportunity to measure cosmic shear accurately on small scales. Using 260 parallel orbits in Sloan textiti {F775W} we will measure for the first time: beginlistosetlength sep0cm setlengthemsep0cm setlengthopsep0cm em the cosmic shear variance on scales Omega_m^0.5, with signal-to-noise {s/n} 20, and the mass density Omega_m with s/n=4. They will be done at small angular scales where non-linear effects dominate the power spectrum, providing a test of the gravitational instability paradigm for structure formation. Measurements on these scales are not possible from the ground, because of the systematic effects induced by PSF smearing from seeing. Having many independent lines of sight reduces the uncertainty due to cosmic variance, making parallel observations ideal.

  17. Insulation interlaminar shear strength testing with compression and irradiation

    International Nuclear Information System (INIS)

    McManamy, T.J.; Brasier, J.E.; Snook, P.

    1989-01-01

    The Compact Ignition Tokamak (CIT) project identified the need for research and development for the insulation to be used in the toroidal field coils. The requirements included tolerance to a combination of high compression and shear and a high radiation dose. Samples of laminate-type sheet material were obtained from commercial vendors. The materials included various combinations of epoxy, polyimide, E-glass, S-glass, and T-glass. The T-glass was in the form of a three-dimensional weave. The first tests were with 50 x 25 x 1 mm samples. These materials were loaded in compression and then to failure in shear. At 345-MPa compression, the interlaminar shear strength was generally in the range of 110 to 140 MPa for the different materials. A smaller sample configuration was developed for irradiation testing. The data before irradiation were similar to those for the larger samples but approximately 10% lower. Limited fatigue testing was also performed by cycling the shear load. No reduction in shear strength was found after 50,000 cycles at 90% of the failure stress. Because of space limitations, only three materials were chosen for irradiation: two polyimide systems and one epoxy system. All used boron-free glass. The small shear/compression samples and some flexure specimens were irradiated to 4 x 10 9 and 2 x 10 10 rad in the Advanced Technology Reactor at Idaho National Engineering Laboratory. A lead shield was used to ensure that the majority of the dose was from neutrons. The shear strength with compression before and after irradiation at the lower dose was determined. Flexure strength and the results from irradiation at the higher dose level will be available in the near future. 7 refs., 7 figs., 2 tabs

  18. Modeling and implementation of wind shear data

    Science.gov (United States)

    Frost, Walter

    1987-01-01

    The problems of implementing the JAWS wind shear data are discussed. The data sets are described from the view of utilizing them in an aircraft performance computer program. Then, some of the problems of nonstandard procedures are described in terms of programming the equations of aircraft motion when the effects of temporal and spatially variable winds are included. Finally, some of the computed effects of the various wind shear terms are shown.

  19. Anomalous transport due to shear-Alfven waves

    International Nuclear Information System (INIS)

    Lee, W.W.; Chance, M.S.; Okuda, H.

    1980-10-01

    The behavior of shear-Alfven eigenmodes and the accompanied anomalous transport have been investigated. In the particle simulation, equilibrium thermal fluctuations associated with the eigenmodes have been observed to nullify the zeroth-order shear near the rational surface through the induced second-order eddy current, and, in turn, give rise to the formation of magnetic islands which cause rapid electron energy transport in the region. The theoretical verification of the observed behavior is discussed

  20. CCM proteins control endothelial β1 integrin dependent response to shear stress

    Directory of Open Access Journals (Sweden)

    Zuzana Macek Jilkova

    2014-11-01

    Full Text Available Hemodynamic shear stress from blood flow on the endothelium critically regulates vascular function in many physiological and pathological situations. Endothelial cells adapt to shear stress by remodeling their cytoskeletal components and subsequently by changing their shape and orientation. We demonstrate that β1 integrin activation is critically controlled during the mechanoresponse of endothelial cells to shear stress. Indeed, we show that overexpression of the CCM complex, an inhibitor of β1 integrin activation, blocks endothelial actin rearrangement and cell reorientation in response to shear stress similarly to β1 integrin silencing. Conversely, depletion of CCM2 protein leads to an elongated “shear-stress-like” phenotype even in the absence of flow. Taken together, our findings reveal the existence of a balance between positive extracellular and negative intracellular signals, i.e. shear stress and CCM complex, for the control of β1 integrin activation and subsequent adaptation of vascular endothelial cells to mechanostimulation by fluid shear stress.