"Miss! I'm Done!" Finishing Craft Assignments as a Situated Activity System in Preschool

Science.gov (United States)

Deunk, Marjolein; Berenst, Jan; de Glopper, Kees

2010-01-01

We describe the Situated Activity System of finishing craft assignments in preschool: the specific, routinized way that child and teacher jointly close the child's craft assignment, employing a specific discourse pattern. We analyzed the interactions of 14 Dutch children between 2.1 and 3.10 years old while they were finishing their craft…

Pilot randomized trial of a volitional help sheet-based tool to increase leisure time physical activity in breast cancer survivors.

Science.gov (United States)

Chapman, Janine; Fletcher, Chloe; Flight, Ingrid; Wilson, Carlene

2018-05-16

To develop and test a volitional help sheet-based tool to improve physical activity in breast cancer survivors compared to a standard self-generated implementation intention intervention. Pilot randomized trial conducted online over 3 months. Participants were randomized to an online volitional help sheet (n = 50) or implementation intention (n = 51) intervention. Measures were taken at baseline, 1 and 3 months. The main outcome measure was moderate-strenuous leisure time physical activity. Secondary outcomes were health-related quality of life and mood. Participants exposed to the volitional help sheet and implementation intention interventions showed similar effects after 1 month, with both groups reporting a significant increase in moderate-strenuous physical activity. After 3 months, the initial increase in physical activity was maintained by the volitional help sheet group, but not the implementation intention group. Improvements were also found for negative affect and emotional quality of life. While both interventions show promise in promoting physical activity in breast cancer survivors, the volitional help sheet may be more effective for facilitating lasting change and emotional well-being. Findings suggest that the volitional help sheet may have potential to offer a cost-effective contribution to consumer-led tertiary preventive health. Future research should test these initial findings in a definitive trial. Statement of contribution What is already known on this subject? Physical activity is important for optimizing health in breast cancer survivors. Despite this, physical activity in this cohort remains low. Theory-based strategies are needed to help breast cancer survivors independently manage and maintain regular physical activity over the long term. What does this study add? Online planning interventions can improve physical activity in breast cancer survivors. Volitional help sheets, but not implementation intentions, show sustained

Synthesis of TiO2 nanorod-decorated graphene sheets and their highly efficient photocatalytic activities under visible-light irradiation

International Nuclear Information System (INIS)

Lee, Eunwoo; Hong, Jin-Yong; Kang, Haeyoung; Jang, Jyongsik

2012-01-01

Highlights: ► TiO 2 nanorods were successfully decorated on the surface of graphene sheets. ► Population of TiO 2 nanorods can be controlled by changing experimental conditions. ► TiO 2 nanorod-decorated graphene sheets have an expanded light absorption range. ► TiO 2 nanorod-decorated graphene sheets showed unprecedented photocatalytic activity. - Abstract: The titanium dioxide (TiO 2 ) nanorod-decorated graphene sheets photocatalysts with different TiO 2 nanorods population have been synthesized by a simple non-hydrolytic sol–gel approach. Electron microscopy and X-ray diffraction analysis indicated that the TiO 2 nanorods are well-dispersed and successfully anchored on the graphene sheet surface through the formation of covalent bonds between Ti and C atoms. The photocatalytic activities are evaluated in terms of the efficiencies of photodecomposition and adsorption of methylene blue (MB) in aqueous solution under visible-light irradiation. The as-synthesized TiO 2 nanorod-decorated graphene sheets showed unprecedented photodecomposition efficiency compared to the pristine TiO 2 nanorods and the commercial TiO 2 (P-25, Degussa) under visible-light. It is believed that this predominant photocatalytic activity is due to the synergistic contribution of both a retarded charge recombination rate caused by a high electronic mobility of graphene and an increased surface area originated from nanometer-sized TiO 2 nanorods. Furthermore, photoelectrochemical study is performed to give deep insights into the primary roles of graphene that determines the photocatalytic activity.

Sequence-specific 1H NMR resonance assignments of Bacillus subtilis HPr: Use of spectra obtained from mutants to resolve spectral overlap

International Nuclear Information System (INIS)

Wittekind, M.; Klevit, R.E.; Reizer, J.

1990-01-01

On the basis of an analysis of two-dimensional 1 H NMR spectra, the complete sequence-specific 1 H NMR assignments are presented for the phosphocarrier protein HPr from the Gram-positive bacterium Bacillus subtilis. During the assignment procedure, extensive use was made of spectra obtained from point mutants of HPr in order to resolve spectral overlap and to provide verification of assignments. Regions of regular secondary structure were identified by characteristic patterns of sequential backbone proton NOEs and slowly exchanging amide protons. B subtilis HPr contains four β-strands that form a single antiparallel β-sheet and two well-defined α-helices. There are two stretches of extended backbone structure, one of which contains the active site His 15 . The overall fold of the protein is very similar to that of Escherichia coli HPr determined by NMR studies

AI applications in sheet metal forming

CERN Document Server

Hussein, Hussein

2017-01-01

This book comprises chapters on research work done around the globe in the area of artificial intelligence (AI) applications in sheet metal forming. The first chapter offers an introduction to various AI techniques and sheet metal forming, while subsequent chapters describe traditional procedures/methods used in various sheet metal forming processes, and focus on the automation of those processes by means of AI techniques, such as KBS, ANN, GA, CBR, etc. Feature recognition and the manufacturability assessment of sheet metal parts, process planning, strip-layout design, selecting the type and size of die components, die modeling, and predicting die life are some of the most important aspects of sheet metal work. Traditionally, these activities are highly experience-based, tedious and time consuming. In response, researchers in several countries have applied various AI techniques to automate these activities, which are covered in this book. This book will be useful for engineers working in sheet metal industri...

12 CFR 615.5212 - Credit conversion factors-off-balance sheet items.

Science.gov (United States)

2010-01-01

...). The resultant credit equivalent amount is assigned to the appropriate risk-weight category described... directly or indirectly retains or assumes credit risk. For risk participations in such arrangements... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Credit conversion factors-off-balance sheet...

HYDRO-ABRASIVE JET CLEANING TECHNOLOGY OF STEEL SHEETS DESIGNED FOR LASER CUTTING

Directory of Open Access Journals (Sweden)

I. V. Kachanov

2013-01-01

Full Text Available Investigations executed by the BNTU “Shipbuilding and hydraulics” department have shown that rather efficient implementation of the requirements to the metal sheet surface designed for laser cutting can be achieved by using hydro-abrasive jet cleaning while applying water pump equipment with the range of pressure – 20–40 MPa. Type of working fluid plays a significant role for obtaining surface of the required quality. The conducted experiments have demonstrated that the efficient solution of the assigned problems can be ensured by using a working fluid containing bentonite clay, surface-active agent polyacrylamide, soda ash and the rest water.

Writing by Number: Teaching Students to Read the Balance Sheet.

Science.gov (United States)

Cross, Mary

1990-01-01

Describes an assignment in which students write a short memo report analyzing and comparing both what a company says in its annual report and what its balance sheet shows. Describes four simple mathematical formulas students can use to quickly diagnose a company's financial health. Appends a sample of the short report format. (RS)

Visible-light promoted catalytic activity of dumbbell-like Au nanorods supported on graphene/TiO2 sheets towards hydrogenation reaction

Science.gov (United States)

Dai, Yunqian; Zhu, Mingyun; Wang, Xiaotian; Wu, Yanan; Huang, Chengqian; Fu, Wanlin; Meng, Xiangyu; Sun, Yueming

2018-06-01

In this work, the rationally-designed sharp corners on Au nanorods tremendously improved the catalytic activity, particularly in the presence of visible light irradiation, towards the hydrogenation of 4-nitrophenol to 4-aminophenol. A strikingly increased rate constant of 50.6 g‑1 s‑1 L was achieved in M-Au-3, which was 41.8 times higher than that of parent Au nanorods under dark conditions. The enhanced activities were proportional to the extent of the protruding sharp corners. Furthermore, remarkably enhanced activities were achieved in novel ternary Au/RGO/TiO2 sheets, which were endowed with a 52.0 times higher rate constant than that of straight Au nanorods. These remarkably enhanced activities were even higher than those of previously reported 3–5 nm Au and 3 nm Pt nanoparticles. It was systematically observed that there are three aspects to the synergistic effects between Au and RGO sheets: (i) electron transfer from RGO to Au, (ii) a high concentration of p-nitrophenol close to dumbbell-like Au nanorods on RGO sheets, and (iii) increased local reaction temperature from the photothermal effect of both dumbbell-like Au nanorods and RGO sheets.

Ice_Sheets_CCI: Essential Climate Variables for the Greenland Ice Sheet

Science.gov (United States)

Forsberg, R.; Sørensen, L. S.; Khan, A.; Aas, C.; Evansberget, D.; Adalsteinsdottir, G.; Mottram, R.; Andersen, S. B.; Ahlstrøm, A.; Dall, J.; Kusk, A.; Merryman, J.; Hvidberg, C.; Khvorostovsky, K.; Nagler, T.; Rott, H.; Scharrer, M.; Shepard, A.; Ticconi, F.; Engdahl, M.

2012-04-01

As part of the ESA Climate Change Initiative (www.esa-cci.org) a long-term project "ice_sheets_cci" started January 1, 2012, in addition to the existing 11 projects already generating Essential Climate Variables (ECV) for the Global Climate Observing System (GCOS). The "ice_sheets_cci" goal is to generate a consistent, long-term and timely set of key climate parameters for the Greenland ice sheet, to maximize the impact of European satellite data on climate research, from missions such as ERS, Envisat and the future Sentinel satellites. The climate parameters to be provided, at first in a research context, and in the longer perspective by a routine production system, would be grids of Greenland ice sheet elevation changes from radar altimetry, ice velocity from repeat-pass SAR data, as well as time series of marine-terminating glacier calving front locations and grounding lines for floating-front glaciers. The ice_sheets_cci project will involve a broad interaction of the relevant cryosphere and climate communities, first through user consultations and specifications, and later in 2012 optional participation in "best" algorithm selection activities, where prototype climate parameter variables for selected regions and time frames will be produced and validated using an objective set of criteria ("Round-Robin intercomparison"). This comparative algorithm selection activity will be completely open, and we invite all interested scientific groups with relevant experience to participate. The results of the "Round Robin" exercise will form the algorithmic basis for the future ECV production system. First prototype results will be generated and validated by early 2014. The poster will show the planned outline of the project and some early prototype results.

Contact replacement for NMR resonance assignment.

Science.gov (United States)

Xiong, Fei; Pandurangan, Gopal; Bailey-Kellogg, Chris

2008-07-01

Complementing its traditional role in structural studies of proteins, nuclear magnetic resonance (NMR) spectroscopy is playing an increasingly important role in functional studies. NMR dynamics experiments characterize motions involved in target recognition, ligand binding, etc., while NMR chemical shift perturbation experiments identify and localize protein-protein and protein-ligand interactions. The key bottleneck in these studies is to determine the backbone resonance assignment, which allows spectral peaks to be mapped to specific atoms. This article develops a novel approach to address that bottleneck, exploiting an available X-ray structure or homology model to assign the entire backbone from a set of relatively fast and cheap NMR experiments. We formulate contact replacement for resonance assignment as the problem of computing correspondences between a contact graph representing the structure and an NMR graph representing the data; the NMR graph is a significantly corrupted, ambiguous version of the contact graph. We first show that by combining connectivity and amino acid type information, and exploiting the random structure of the noise, one can provably determine unique correspondences in polynomial time with high probability, even in the presence of significant noise (a constant number of noisy edges per vertex). We then detail an efficient randomized algorithm and show that, over a variety of experimental and synthetic datasets, it is robust to typical levels of structural variation (1-2 AA), noise (250-600%) and missings (10-40%). Our algorithm achieves very good overall assignment accuracy, above 80% in alpha-helices, 70% in beta-sheets and 60% in loop regions. Our contact replacement algorithm is implemented in platform-independent Python code. The software can be freely obtained for academic use by request from the authors.

Development of a check sheet for collecting information necessary for occupational safety and health activities and building relevant systems in overseas business places.

Science.gov (United States)

Kajiki, Shigeyuki; Kobayashi, Yuichi; Uehara, Masamichi; Nakanishi, Shigemoto; Mori, Koji

2016-06-07

This study aimed to develop an information gathering check sheet to efficiently collect information necessary for Japanese companies to build global occupational safety and health management systems in overseas business places. The study group consisted of 2 researchers with occupational physician careers in a foreign-affiliated company in Japan and 3 supervising occupational physicians who were engaged in occupational safety and health activities in overseas business places. After investigating information and sources of information necessary for implementing occupational safety and health activities and building relevant systems, we conducted information acquisition using an information gathering check sheet in the field, by visiting 10 regions in 5 countries (first phase). The accuracy of the information acquired and the appropriateness of the information sources were then verified in study group meetings to improve the information gathering check sheet. Next, the improved information gathering check sheet was used in another setting (3 regions in 1 country) to confirm its efficacy (second phase), and the information gathering check sheet was thereby completed. The information gathering check sheet was composed of 9 major items (basic information on the local business place, safety and health overview, safety and health systems, safety and health staff, planning/implementation/evaluation/improvement, safety and health activities, laws and administrative organs, local medical care systems and public health, and medical support for resident personnel) and 61 medium items. We relied on the following eight information sources: the internet, company (local business place and head office in Japan), embassy/consulate, ISO certification body, university or other educational institutions, and medical institutions (aimed at Japanese people or at local workers). Through multiple study group meetings and a two-phased field survey (13 regions in 6 countries), an information

Enhanced activity and stability of Pt catalysts on functionalized graphene sheets for electrocatalytic oxygen reduction

Energy Technology Data Exchange (ETDEWEB)

Kou, Rong; Shao, Yuyan; Wang, Donghai; Engelhard, Mark H.; Kwak, Ja Hun; Wang, Jun; Viswanathan, Vilayanur V.; Wang, Chongmin; Lin, Yuehe; Wang, Yong; Liu, Jun [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Aksay, Ilhan A. [Department of Chemical Engineering, Princeton University, Princeton, NJ 08544 (United States)

2009-05-15

Electrocatalysis of oxygen reduction using Pt nanoparticles supported on functionalized graphene sheets (FGSs) was studied. FGSs were prepared by thermal expansion of graphite oxide. Pt nanoparticles with average diameter of 2 nm were uniformly loaded on FGSs by impregnation methods. Pt-FGS showed a higher electrochemical surface area and oxygen reduction activity with improved stability as compared with the commercial catalyst. Transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical characterization suggest that the improved performance of Pt-FGS can be attributed to smaller particle size and less aggregation of Pt nanoparticles on the functionalized graphene sheets. (author)

Evolution of Various Library Instruction Strategies: Using Student Feedback to Create and Enhance Online Active Learning Assignments

Directory of Open Access Journals (Sweden)

Marcie Lynne Jacklin

2013-06-01

Full Text Available This case study traces the evolution of library assignments for biological science students from paper-based workbooks in a blended (hands-on workshop to blended learning workshops using online assignments to online active learning modules which are stand-alone without any face-to-face instruction. As the assignments evolved to adapt to online learning supporting materials in the form of PDFs (portable document format, screen captures and screencasting were embedded into the questions as teaching moments to replace face-to-face instruction. Many aspects of the evolution of the assignment were based on student feedback from evaluations, input from senior lab demonstrators and teaching assistants, and statistical analysis of the students’ performance on the assignment. Advantages and disadvantages of paper-based and online assignments are discussed. An important factor for successful online learning may be the ability to get assistance.

TSCA Chemical Data Reporting Fact Sheet: Reporting Manufactured Chemical Substances from Metal Mining and Related Activities

Science.gov (United States)

This fact sheet provides guidance on the Chemical Data Reporting (CDR) rule requirements related to the reporting of mined metals, intermediates, and byproducts manufactured during metal mining and related activities.

Modelling the effects of ice-sheet activity on CO2 outgassing by Icelandic volcanoes

Science.gov (United States)

Armitage, J. J.; Ferguson, D.; Petersen, K. D.; Creyts, T. T.

2017-12-01

Glacial cycles may play a significant role in mediating the flux of magmatic CO2 between the Earth's mantle and atmosphere. In Iceland, it is thought that late-Pleistocene deglaciation led to a significant volcanic pulse, evidenced by increased post-glacial lava volumes and changes in melt chemistry consistent with depressurization. Investigating the extent to which glacial activity may have affected volcanic CO2 emissions from Iceland, and crucially over what timescale, requires detailed knowledge of how the magma system responded to the growth and collapse of the ice-sheet before and after the LGM. To investigate this, we coupled a model of magma generation and transport with a history of ice-sheet activity. Our results show that the emplacement and removal of the LGM ice-sheet likely led to two significant pulses of magmatic CO2. The first, and most significant of these, is associated with ice-sheet growth and occurs as the magma system recovers from glacial loading. This recovery happens from the base of the melting region upwards, producing a pulse of CO2 rich magma that is predicted to reach the surface around 20 ka after the loading event, close in time to the LGM. The second peak in CO2 output occurs abruptly following deglaciation as a consequence of increased rates of melt generation and transport in the shallow mantle. Although these post-glacial melts are relatively depleted in CO2, the increase in magma flux leads to a short-lived period of elevated CO2 emissions. Our results therefore suggest a negative feedback, whereby ice-sheet growth produces a delayed pulse of magmatic CO2, which, in addition to increased geothermal heat flux, may contribute towards driving deglaciation, which itself then causes further magmatism and CO2 outgassing. This model is consistent with the seismic structure of the asthenosphere below Iceland, and the established compositional and volumetric trends for sub- and post-glacial volcanism in Iceland. These trends show that

Automated grading of homework assignments and tests in introductory and intermediate statistics courses using active server pages.

Science.gov (United States)

Stockburger, D W

1999-05-01

Active server pages permit a software developer to customize the Web experience for users by inserting server-side script and database access into Web pages. This paper describes applications of these techniques and provides a primer on the use of these methods. Applications include a system that generates and grades individualized homework assignments and tests for statistics students. The student accesses the system as a Web page, prints out the assignment, does the assignment, and enters the answers on the Web page. The server, running on NT Server 4.0, grades the assignment, updates the grade book (on a database), and returns the answer key to the student.

Collisionless current sheet equilibria

Science.gov (United States)

Neukirch, T.; Wilson, F.; Allanson, O.

2018-01-01

Current sheets are important for the structure and dynamics of many plasma systems. In space and astrophysical plasmas they play a crucial role in activity processes, for example by facilitating the release of magnetic energy via processes such as magnetic reconnection. In this contribution we will focus on collisionless plasma systems. A sensible first step in any investigation of physical processes involving current sheets is to find appropriate equilibrium solutions. The theory of collisionless plasma equilibria is well established, but over the past few years there has been a renewed interest in finding equilibrium distribution functions for collisionless current sheets with particular properties, for example for cases where the current density is parallel to the magnetic field (force-free current sheets). This interest is due to a combination of scientific curiosity and potential applications to space and astrophysical plasmas. In this paper we will give an overview of some of the recent developments, discuss their potential applications and address a number of open questions.

Relevance of southward magnetic fields in the neutral sheet to anisotropic distribution of energetic electrons and substorm activity

International Nuclear Information System (INIS)

Lui, A.T.Y.; Meng, C.

1979-01-01

The implications of southward magnetic fields at the magnetotail neutral sheet to the development of streaming anisotropy of energetic electrons and magnetospheric substorm activity are examined. Magnetic field and energetic particle measurements from the Imp 6 spacecraft, the AE index, and global auroral images from DMSP spacecraft are utilized in this study. Criteria are developed to identify events of southward magnetic fields at the neutral sheet which imply the presence of X-type magnetic neutral lines. Several features of the observations suggest that the southward magnetic fields and the implied X-type neutral lines are associated with magnetic bubbles in the neutral sheet region. It is found that the signatures of magnetic bubbles are sometimes detected in association with tailward streaming and flux enhancement of energetic electrons (47 keV< E<350keV). A cigar-shaped anisotropy in the energetic electron distribution is frequently but not always observed before the onset of tailward streaming of energetic electrons. The tailward streaming is magnetic field-aligned and occurs in the form of bursts, suggestic electrons. The tailward streaming is magnetic field-aligned and occurs in the form of bursts, suggesting that the generating process is activated somewhat quasi-periodically and is not in a steady state. Signatures of magnetic bubbles are also detected without any substantial enhancement or detectable tailward streaming of energetic electrons. By comparing Imp 6 observations with the AW index and global auroral images from DMSP spacecraft. It is found that signatures of magnetic bubbles in the neutral sheet are observed during substorms as well as during quiet geomagnetic conditions, indicating that magnetic bubbles are intrinsic features of the neutral sheet in the magnetotail regardless of substorm activity

French electric power balance sheet 2006

International Nuclear Information System (INIS)

Derdevet, Michel; Usatorre, Karine de

2007-01-01

The mission of RTE, the French electricity Transportation grid, a public service assignment, is to balance the electricity supply and demand in real time. This report presents RTE's technical results for the year 2006: key figures of the electricity balance sheet, RTE's public utility commitments, efficient market mechanisms and free flow of trades, lessons learnt from the power breakdown of November 4, 2006. The evolution of RTE's infrastructures and production means, the contract with Gaz de France for the improvement of Brittany's security of supply, and the results of RTE's 2006 satisfaction survey are presented in appendixes

Photovoltaic self-consumption: reference activity sheets

International Nuclear Information System (INIS)

2016-01-01

In order to promote the use of photovoltaic energy in self-consumption, Enerplan, the French association of solar energy professionals, has edited a set of reference sheets comprising the main technical and economic data of recent installations (cold generation facility, water treatment plant, farm, commercial and public buildings), in various French regions: description of the installation, project owner testimony, technical characteristics of the site, expected results, economic data, production/consumption results

Spread-sheet application to classify radioactive material for shipment

International Nuclear Information System (INIS)

Brown, A.N.

1998-01-01

A spread-sheet application has been developed at the Idaho National Engineering and Environmental Laboratory to aid the shipper when classifying nuclide mixtures of normal form, radioactive materials. The results generated by this spread-sheet are used to confirm the proper US DOT classification when offering radioactive material packages for transport. The user must input to the spread-sheet the mass of the material being classified, the physical form (liquid or not) and the activity of each regulated nuclide. The spread-sheet uses these inputs to calculate two general values: 1)the specific activity of the material and a summation calculation of the nuclide content. The specific activity is used to determine if the material exceeds the DOT minimal threshold for a radioactive material. If the material is calculated to be radioactive, the specific activity is also used to determine if the material meets the activity requirement for one of the three low specific activity designations (LSA-I, LSA-II, LSA-III, or not LSA). Again, if the material is calculated to be radioactive, the summation calculation is then used to determine which activity category the material will meet (Limited Quantity, Type A, Type B, or Highway Route Controlled Quantity). This spread-sheet has proven to be an invaluable aid for shippers of radioactive materials at the Idaho National Engineering and Environmental Laboratory. (authors)

The mechanistic exploration of porous activated graphene sheets-anchored SnO2 nanocrystals for application in high-performance Li-ion battery anodes.

Science.gov (United States)

Yang, Yingchang; Ji, Xiaobo; Lu, Fang; Chen, Qiyuan; Banks, Craig E

2013-09-28

Porous activated graphene sheets have been for the first time exploited herein as encapsulating substrates for lithium ion battery (LIB) anodes. The as-fabricated SnO2 nanocrystals-porous activated graphene sheet (AGS) composite electrode exhibits improved electrochemical performance as an anode material for LIBs, such as better cycle performance and higher rate capability in comparison with graphene sheets, activated graphene sheets, bare SnO2 and SnO2-graphene sheet composites. The superior electrochemical performances of the designed anode can be ascribed to the porous AGS substrate, which improves the electrical conductivity of the electrode, inhibits agglomeration between particles and effectively buffers the strain from the volume variation during Li(+)-intercalation-de-intercalation and provides more cross-plane diffusion channels for Li(+) ions. As a result, the designed anode exhibits an outstanding capacity of up to 610 mA h g(-1) at a current density of 100 mA g(-1) after 50 cycles and a good rate performance of 889, 747, 607, 482 and 372 mA h g(-1) at a current density of 100, 200, 500, 1000, and 2000 mA g(-1), respectively. This work is of importance for energy storage as it provides a new substrate for the design and implementation of next-generation LIBs exhibiting exceptional electrochemical performances.

Pressure balance between lobe and plasma sheet

International Nuclear Information System (INIS)

Baumjohann, W.; Paschmann, G.; Luehr, H.

1990-01-01

Using eight months of AMPTE/IRM plasma and magnetic field data, the authors have done a statistical survey on the balance of total (thermal and magnetic) pressure in the Earth's plasma sheet and tail lobe. About 300,000 measurements obtained in the plasma sheet and the lobe were compared for different levels of magnetic activity as well as different distances from the Earth. The data show that lobe and plasma sheet pressure balance very well. Even in the worst case they do not deviate by more than half of the variance in the data itself. Approximately constant total pressure was also seen during a quiet time pass when IRM traversed nearly the whole magnetotail in the vertical direction, from the southern hemisphere lobe through the neutral sheet and into the northern plasma sheet boundary layer

A statistical study of current-sheet formation above solar active regions based on selforganized criticality

Science.gov (United States)

Dimitropoulou, M.; Isliker, H.; Vlahos, L.; Georgoulis, M.; Anastasiadis, A.; Toutountzi, A.

2013-09-01

We treat flaring solar active regions as physical systems having reached the self-organized critical state. Their evolving magnetic configurations in the low corona may satisfy an instability criterion, related to the excession of a specific threshold in the curl of the magnetic field. This imposed instability criterion implies an almost zero resistivity everywhere in the solar corona, except in regions where magnetic-field discontinuities and. hence, local currents, reach the critical value. In these areas, current-driven instabilities enhance the resistivity by many orders of magnitude forming structures which efficiently accelerate charged particles. Simulating the formation of such structures (thought of as current sheets) via a refined SOC cellular-automaton model provides interesting information regarding their statistical properties. It is shown that the current density in such unstable regions follows power-law scaling. Furthermore, the size distribution of the produced current sheets is best fitted by power laws, whereas their formation probability is investigated against the photospheric magnetic configuration (e.g. Polarity Inversion Lines, Plage). The average fractal dimension of the produced current sheets is deduced depending on the selected critical threshold. The above-mentioned statistical description of intermittent electric field structures can be used by collisional relativistic test particle simulations, aiming to interpret particle acceleration in flaring active regions and in strongly turbulent media in astrophysical plasmas. The above work is supported by the Hellenic National Space Weather Research Network (HNSWRN) via the THALIS Programme.

An active-learning assignment requiring pharmacy students to write medicinal chemistry examination questions.

Science.gov (United States)

Kolluru, Srikanth

2012-08-10

To implement and assess the effectiveness of an assignment requiring doctor of pharmacy (PharmD) students to write examination questions for the medicinal chemistry sections of a pharmacotherapeutics course. Students were divided into groups of 5-6 and given detailed instructions and grading rubrics for writing multiple-choice examination questions on medicinal chemistry topics. The compiled student-written questions for each examination were provided to the entire class as a study aid. Approximately 5% of the student-written questions were used in course examinations. Student appreciation of and performance in the medicinal chemistry portion of the course was significantly better than that of the previous year's class. Also, students' responses on a qualitative survey instrument indicated that the assignment provided students' guidance on which concepts to focus on, helped them retain knowledge better, and fostered personal exploration of the content, which led to better performance on examinations. Adding an active-learning assignment in which students write examination questions for the medicinal chemistry portion of a pharmacotherapeutics course was an effective means of increasing students engagement in the class and knowledge of the course material.

Ice Sheet Model Intercomparison Project (ISMIP6) contribution to CMIP6

Science.gov (United States)

Nowicki, Sophie M.J.; Payne, Tony; Larour, Eric; Seroussi, Helene; Goelzer, Heiko; Lipscomb, William; Gregory, Jonathan; Abe-Ouchi, Ayako; Shepherd, Andrew

2018-01-01

Reducing the uncertainty in the past, present and future contribution of ice sheets to sea-level change requires a coordinated effort between the climate and glaciology communities. The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) is the primary activity within the Coupled Model Intercomparison Project – phase 6 (CMIP6) focusing on the Greenland and Antarctic Ice Sheets. In this paper, we describe the framework for ISMIP6 and its relationship to other activities within CMIP6. The ISMIP6 experimental design relies on CMIP6 climate models and includes, for the first time within CMIP, coupled ice sheet – climate models as well as standalone ice sheet models. To facilitate analysis of the multi-model ensemble and to generate a set of standard climate inputs for standalone ice sheet models, ISMIP6 defines a protocol for all variables related to ice sheets. ISMIP6 will provide a basis for investigating the feedbacks, impacts, and sea-level changes associated with dynamic ice sheets and for quantifying the uncertainty in ice-sheet-sourced global sea-level change. PMID:29697697

Evaluation of alternative flow sheets for upgrade of the Process Waste Treatment Plant

International Nuclear Information System (INIS)

Robinson, S.M.

1991-04-01

Improved chemical precipitation and/or ion-exchange (IX) methods are being developed at the Oak Ridge National Laboratory (ORNL) in an effort to reduce waste generation at the Process Waste Treatment Plant (PWTP). A wide variety of screening tests were performed on potential precipitation techniques and IX materials on a laboratory scale. Two of the more promising flow sheets have been tested on pilot and full scales. The data were modeled to determine the operating conditions and waste generation at plant-scale and used to develop potential flow sheets for use at the PWTP. Each flow sheet was evaluated using future-valve economic analysis and performance ratings (where numerical values were assigned to costs, process flexibility and simplicity, stage of development, waste reduction, environmental and occupational safety, post-processing requirements, and final waste form). The results of this study indicated that several potential flow sheets should be considered for further development, and more detailed cost estimates should be made before a final selection is made for upgrade of the PWTP. 19 refs., 52 figs., 22 tabs

Decontamination sheet

International Nuclear Information System (INIS)

Hirose, Emiko; Kanesaki, Ken.

1995-01-01

The decontamination sheet of the present invention is formed by applying an adhesive on one surface of a polymer sheet and releasably appending a plurality of curing sheets. In addition, perforated lines are formed on the sheet, and a decontaminating agent is incorporated in the adhesive. This can reduce the number of curing operation steps when a plurality steps of operations for radiation decontamination equipments are performed, and further, the amount of wastes of the cured sheets, and operator's exposure are reduced, as well as an efficiency of the curing operation can be improved, and propagation of contamination can be prevented. (T.M.)

Ice Sheet Model Intercomparison Project (ISMIP6) Contribution to CMIP6

Science.gov (United States)

Nowicki, Sophie M. J.; Payne, Tony; Larour, Eric; Seroussi, Helene; Goelzer, Heiko; Lipscomb, William; Gregory, Jonathan; Abe-Ouchi, Ayako; Shepherd, Andrew

2016-01-01

Reducing the uncertainty in the past, present, and future contribution of ice sheets to sea-level change requires a coordinated effort between the climate and glaciology communities. The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) is the primary activity within the Coupled Model Intercomparison Project phase 6 (CMIP6) focusing on the Greenland and Antarctic ice sheets. In this paper, we describe the framework for ISMIP6 and its relationship with other activities within CMIP6. The ISMIP6 experimental design relies on CMIP6 climate models and includes, for the first time within CMIP, coupled ice-sheetclimate models as well as standalone ice-sheet models. To facilitate analysis of the multi-model ensemble and to generate a set of standard climate inputs for standalone ice-sheet models, ISMIP6 defines a protocol for all variables related to ice sheets. ISMIP6 will provide a basis for investigating the feedbacks, impacts, and sea-level changes associated with dynamic ice sheets and for quantifying the uncertainty in ice-sheet-sourced global sea-level change.

1H and 15N resonance assignments of oxidized flavodoxin from Anacystis nidulans with 3D NMR

International Nuclear Information System (INIS)

Clubb, R.T.; Thanabal, V.; Wagner, G.; Osborne, C.

1991-01-01

Proton and nitrogen-15 sequence-specific nuclear magnetic resonance assignments have been determined for recombinant oxidized flavodoxin from Anacystis nidulans. Assignments were obtained by using 15 N- 1 H heteronuclear three-dimensional (3D) NMR spectroscopy on a uniformly nitrogen-15 enriched sample of the protein, pH 6.6, at 30C. For 165 residues, the backbone and a large fraction of the side-chain proton resonances have been assigned. Medium- and long-range NOE's have been used to characterize the secondary structure. In solution, flavodoxin consists of a five-stranded parallel β sheet involving residues 3-9, 31-37, 49-56, 81-89, 114-117, and 141-144. Medium-range NOE's indicate that presence of several helices. Several 15 N and 1 H resonances of the flavin mononucleotide (FMN) prosthetic group have been assigned. The FMN-binding site has been investigated by using polypeptide-FMN NOE's

Off-balance sheet exposures and banking crises in OECD countries

OpenAIRE

Barrell, R; Davis, P; Liadze, I; Karim, D

2012-01-01

Against the background of the acknowledged importance of off-balance-sheet exposures in the sub prime crisis, we seek to investigate whether this was a new phenomenon or common to earlier crises. Using a logit approach to predicting banking crises in 14 OECD countries we find a significant impact of a proxy for the ratio of banks‟ off-balance-sheet activity to total (off and on balance sheet) activity, as well as capital and liquidity ratios, the current account balance and GDP growth. These ...

Region-selective electroless gold plating on polycarbonate sheets by UV-patterning in combination with silver activating

Energy Technology Data Exchange (ETDEWEB)

Zhou Qinghua [Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Zijin' gang Campus, Hangzhou 310058 (China); Chen Hengwu, E-mail: hwchen@zju.edu.c [Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Zijin' gang Campus, Hangzhou 310058 (China); Wang Yi [Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Zijin' gang Campus, Hangzhou 310058 (China)

2010-02-28

A simple, time- and cost-effective approach for region-selective metalization of polycarbonate (PC) surface has been established by combining photoresist-free UV-patterning with tin- and amine-free silver activating and electroless gold plating. The surface of PC sheets was exposed to the UV lights emitted from a low-pressure mercury lamp through a photomask, the micro pattern on the mask being transferred to the PC surface due to the photochemical generation of carboxyl groups on the UV-exposed region. The UV-exposed PC sheets were then treated with an ammoniacal AgNO{sub 3} solution, so that the silver ions were chemisorbed by the photochemically generated carboxyl groups. When the Ag{sup +}-adsorbed PC sheet was immersed into an electroless gold plating bath, shiny gold film quickly deposited on the UV-exposed region, resulting in the formation of a micro gold devices on the PC surface. The whole plating process including UV-exposure, surface activating and gold plating can be completed in about 3-4 h. Attenuated total reflection Fourier transformation infrared spectrometer (ATR-FT-IR), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and scanning electron microscope (SEM) were employed to trace the surface change during the plating process. Cyclic voltammetry (CV) and Scotch-tape test were employed to characterize the electrochemical properties and adhesion strength of the prepared micro gold devices, respectively. The prepared micro gold electrodes were demonstrated for amperometric detection of hydrogen peroxide.

The plasma sheet boundary and Ksub(p)

International Nuclear Information System (INIS)

Freeman, J.W.

1975-01-01

Freeman and Maguire (1967) first drew attention to the intrusion of energetic plasma from the tail to the geostationary orbit during geomagnetically disturbed times. Vasyliunas (1968) reported a correlation between the inward extension of the inner boundary of the plasma sheet and the Ksub(p) index and pointed out that the plasma sheet could occasionally reach the geostationary orbit distance. More recently McIlwain (1972) using the more refined detectors aboard the ATS-5 geostationary space-craft, has emphasized the correlation between the location of the plasma sheet boundary along the ATS orbit and geomagnetic activity. Using some older but unpublished data from the Suprathermal Ion Detector aboard the ATS-1 geostationary satellite, the relation between the local time occurrence of the plasma sheet at the geostationary orbit (6.6Rsub(E)) and Ksub(p) index is reported and then a relationship for the shift in the plasma sheet radial position is derived. (Auth.)

Effect of Cell Sheet Manipulation Techniques on the Expression of Collagen Type II and Stress Fiber Formation in Human Chondrocyte Sheets.

Science.gov (United States)

Wongin, Sopita; Waikakul, Saranatra; Chotiyarnwong, Pojchong; Siriwatwechakul, Wanwipa; Viravaidya-Pasuwat, Kwanchanok

2018-03-01

Cell sheet technology is applied to human articular chondrocytes to construct a tissue-like structure as an alternative treatment for cartilage defect. The effect of a gelatin manipulator, as a cell sheet transfer system, on the quality of the chondrocyte sheets was investigated. The changes of important chondrogenic markers and stress fibers, resulting from the cell sheet manipulation, were also studied. The chondrocyte cell sheets were constructed with patient-derived chondrocytes using a temperature-responsive polymer and a gelatin manipulator as a transfer carrier. The properties of the cell sheets, including sizes, expression levels of collagen type II and I, and the localization of the stress fibers, were assessed and compared with those of the cell sheets harvested without the gelatin manipulator. Using the gelatin manipulator, the original size of the chondrocyte cell sheets was retained with abundant stress fibers, but with a decrease in the expression of collagen type II. Without the gelatin manipulator, although the cell shrinkage occurred, the cell sheet with suppressed stress fiber formation showed significantly higher levels of collagen type II. These results support our observations that stress fiber formation in chondrocyte cell sheets affected the production of chondrogenic markers. These densely packed tissue-like structures possessed a good chondrogenic activity, indicating their potential for use in autologous chondrocyte implantation to treat cartilage defects.

THE MOTRU MINING BASIN – GIS APPLICATION ON SHEET EROSION

Directory of Open Access Journals (Sweden)

Anghel TITU

2008-05-01

Full Text Available The Motru Mining Basin – GIS Application on Sheet Erosion. The activation of the sheet erosion has important negative effects upon the soil profile. The anticipation of this geomorphologic process is important for taking some measures for protecting the susceptible areas. Within our study, we will carry out a quantitative estimation of the soil losses in the Motru Mining Basin, caused by the activation of the sheet erosion mechanism. We will apply the classic methodology proposed by the ROMSEM model of the USLE type by using the GIS technology

An efficient randomized algorithm for contact-based NMR backbone resonance assignment.

Science.gov (United States)

Kamisetty, Hetunandan; Bailey-Kellogg, Chris; Pandurangan, Gopal

2006-01-15

Backbone resonance assignment is a critical bottleneck in studies of protein structure, dynamics and interactions by nuclear magnetic resonance (NMR) spectroscopy. A minimalist approach to assignment, which we call 'contact-based', seeks to dramatically reduce experimental time and expense by replacing the standard suite of through-bond experiments with the through-space (nuclear Overhauser enhancement spectroscopy, NOESY) experiment. In the contact-based approach, spectral data are represented in a graph with vertices for putative residues (of unknown relation to the primary sequence) and edges for hypothesized NOESY interactions, such that observed spectral peaks could be explained if the residues were 'close enough'. Due to experimental ambiguity, several incorrect edges can be hypothesized for each spectral peak. An assignment is derived by identifying consistent patterns of edges (e.g. for alpha-helices and beta-sheets) within a graph and by mapping the vertices to the primary sequence. The key algorithmic challenge is to be able to uncover these patterns even when they are obscured by significant noise. This paper develops, analyzes and applies a novel algorithm for the identification of polytopes representing consistent patterns of edges in a corrupted NOESY graph. Our randomized algorithm aggregates simplices into polytopes and fixes inconsistencies with simple local modifications, called rotations, that maintain most of the structure already uncovered. In characterizing the effects of experimental noise, we employ an NMR-specific random graph model in proving that our algorithm gives optimal performance in expected polynomial time, even when the input graph is significantly corrupted. We confirm this analysis in simulation studies with graphs corrupted by up to 500% noise. Finally, we demonstrate the practical application of the algorithm on several experimental beta-sheet datasets. Our approach is able to eliminate a large majority of noise edges and to

Optimal swimming of a sheet.

Science.gov (United States)

Montenegro-Johnson, Thomas D; Lauga, Eric

2014-06-01

Propulsion at microscopic scales is often achieved through propagating traveling waves along hairlike organelles called flagella. Taylor's two-dimensional swimming sheet model is frequently used to provide insight into problems of flagellar propulsion. We derive numerically the large-amplitude wave form of the two-dimensional swimming sheet that yields optimum hydrodynamic efficiency: the ratio of the squared swimming speed to the rate-of-working of the sheet against the fluid. Using the boundary element method, we show that the optimal wave form is a front-back symmetric regularized cusp that is 25% more efficient than the optimal sine wave. This optimal two-dimensional shape is smooth, qualitatively different from the kinked form of Lighthill's optimal three-dimensional flagellum, not predicted by small-amplitude theory, and different from the smooth circular-arc-like shape of active elastic filaments.

French electric power balance sheet and RTE's technical results for 2004

International Nuclear Information System (INIS)

Derdevet, Michel; Lartigau, Thierry; Coutier, Isabelle

2005-01-01

The mission of RTE, the French electricity Transportation grid, a public service assignment, is to balance the electricity supply and demand in real time. This report presents RTE's preliminary technical results for the year 2004: key figures of the electricity balance sheet, market development, infrastructures performance and evolution, environmental aspects. A second part is devoted to a presentation of the actors of the electricity market, while a third part presents the results of the 2004 RTE's clients survey

Developing and Evaluating Clinical Written Assignment in Clinical Teaching for the Senior B.S. Nursing Students: An action research

Directory of Open Access Journals (Sweden)

Leila Valizadeh

2012-12-01

Full Text Available Introduction: In a four-year undergraduate level , the nursing students have to get prepared in the patients education, designing care plans, applying nursing processes and exercise the clinical decisions, in addition to learning practical skills. Therefore, multiple clinical teaching strategies in nursing must be applied. In this study the sheets for the mentioned fields were designed and used. Methods: In this action research in Tabriz University of Medical Sciences, 64 nursing senior students and related instructors participated. Clinical written assignment included the patient’s health condition sheet, tables showing the used medicines and the precautions, the clinical and paraclinical tests and the results, identifying the patient problems, designing and implementing care plan and writing nursing reports with SOAPIE method. The instructors’ viewpoints were achieved through the group discussions and their notes taken. The perceived competency of the students was obtained through a questionnaire. The qualitative data was analyzed by the content analysis and quantitative using SPSS. Results: Both the students and the instructors agreed with the clinical written assignment. The desired care competency of the students before and after assignment was statistically significant (p<0.05. According to the instructors, intervention was useful for the senior students who have passed the courses needed for completing and using the different parts of these forms. Conclusion: Since a need is always felt in the trends of the nursing clinical teaching, the researchers recommend the clinical written assignment and their application along with other strategies for senior nursing students in clinical teaching.

Up-scalable sheet-to-sheet production of high efficiency perovskite module and solar cells on 6-in. substrate using slot die coating

NARCIS (Netherlands)

Di Giacomo, Francesco; Shanmugam, Santhosh; Fledderus, Henri; Bruijnaers, Bardo J.; Verhees, Wiljan J.H.; Dorenkamper, Maarten S.; Veenstra, Sjoerd C.; Qiu, Weiming; Gehlhaar, Robert; Merckx, Tamara; Aernouts, Tom; Andriessen, Ronn; Galagan, Yulia

2018-01-01

Scalable sheet-to-sheet slot die coating processes have been demonstrated for perovskite solar cells and modules. The processes have been developed on 6 in. × 6 in. glass/ITO substrates for two functional layers: the perovskite photo-active layer and the Spiro-OMeTAD hole transport layer. Perovskite

Dense sheet Z-pinches

International Nuclear Information System (INIS)

Tetsu, Miyamoto

1999-01-01

The steady state and quasi-steady processes of infinite- and finite-width sheet z-pinches are studied. The relations corresponding to the Bennett relation and Pease-Braginskii current of cylindrical fiber z-pinches depend on a geometrical factor in the sheet z-pinches. The finite-width sheet z-pinch is approximated by a segment of infinite-width sheet z-pinch, if it is wide enough, and corresponds to a number of (width/thickness) times fiber z-pinch plasmas of the diameter that equals the sheet thickness. If the sheet current equals this number times the fiber current, the plasma created in the sheet z-pinches is as dense as in the fiber z-pinches. The total energy of plasma and magnetic field per unit mass is approximately equal in both pinches. Quasi-static transient processes are different in several aspects from the fiber z-pinch. No radiation collapse occurs in the sheet z-pinch. The stability is improved in the sheet z-pinches. The fusion criterions and the experimental arrangements to produce the sheet z-pinches are also discussed. (author)

Uranium mining sites - Thematic sheets

International Nuclear Information System (INIS)

2009-01-01

A first sheet proposes comments, data and key numbers about uranium extraction in France: general overview of uranium mining sites, status of waste rock and tailings after exploitation, site rehabilitation. The second sheet addresses the sources of exposure to ionizing radiations due to ancient uranium mining sites: discussion on the identification of these sources associated with these sites, properly due to mining activities or to tailings, or due to the transfer of radioactive substances towards water and to the contamination of sediments, description of the practice and assessment of radiological control of mining sites. A third sheet addresses the radiological exposure of public to waste rocks, and the dose assessment according to exposure scenarios: main exposure ways to be considered, studied exposure scenarios (passage on backfilled path and grounds, stay in buildings built on waste rocks, keeping mineralogical samples at home). The fourth sheet addresses research programmes of the IRSN on uranium and radon: epidemiological studies (performed on mine workers; on French and on European cohorts, French and European studies on the risk of lung cancer associated with radon in housing), study of the biological effects of chronic exposures. The last sheet addresses studies and expertises performed by the IRSN on ancient uranium mining sites in France: studies commissioned by public authorities, radioactivity control studies performed by the IRSN about mining sites, participation of the IRSN to actions to promote openness to civil society

Chemically-modified graphene sheets as an active layer for eco-friendly metal electroplating on plastic substrates

International Nuclear Information System (INIS)

Oh, Joon-Suk; Hwang, Taeseon; Nam, Gi-Yong; Hong, Jung-Pyo; Bae, Ah-Hyun; Son, Sang-Ik; Lee, Geun-Ho; Sung, Hak kyung; Choi, Hyouk Ryeol; Koo, Ja Choon; Nam, Jae-Do

2012-01-01

Eco-friendly nickel (Ni) electroplating was carried out on a plastic substrate using chemically modified graphene sheets as an active and conductive layer to initiate electroplating without using conventional pre-treatment or electroless metal-seeding processes. A graphene oxide (GO) solution was self-assembled on a polyethylene terephthalate (PET) film followed by evaporation to give GO layers (thickness around 6.5 μm) on PET (GO/PET) film. Then, the GO/PET film was chemically and thermally reduced to convert the GO layers to reduced graphene oxide (RGO) layers on the PET substrate. The RGO-coated PET (RGO/PET) film showed the sheet resistance of 100 Ω per square. On RGO/PET film, Ni electroplating was conducted under the constant-current condition and the entire surface of the PET film was completely metalized with Ni without any voids.

Photocatalytic perfermance of sandwich-like BiVO_4 sheets by microwave assisted synthesis

International Nuclear Information System (INIS)

Liu, Suqin; Tang, Huiling; Zhou, Huan; Dai, Gaopeng; Wang, Wanqiang

2017-01-01

Graphical abstract: Sandwich-like BiVO_4 sheets were successfully synthesized via a facile microwave-assisted method. The as-prepared samples exhibit a high activity for the degradation of methyl orange under visible light irradiation. - Highlights: • Sandwich-like BiVO_4 sheets were synthesized by a facile microwave-assisted method. • The presence of PEG-10000 plays a critical role in the formation of BiVO_4 sheets. • Ostwald ripening is the primary driving force for the formation of sandwich-like BiVO_4. • The sandwich-like BiVO_4 sheets exhibit a high visible-light photocatalytic activity. - Abstract: Sandwich-like BiVO_4 sheets were successfully synthesized in an aqueous solution containing bismuth nitrate, ammonium metavanadate and polyethylene glycol with a molecular weight of 10,000 (PEG-10000) using a facile microwave-assisted method. The as-prepared samples were characterized by scanning electron microscopy, N_2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectroscopy. The results show that the presence of PEG-10000 plays a critical role in the formation of BiVO_4 sheets, and Ostwald ripening is the primary driving force for the formation of sandwich-like structures. The sandwich-like BiVO_4 sheets exhibit a high activity for the degradation of methyl orange under visible light irradiation (λ ≥ 420 nm). The enhancement of photocatalytic activity of sandwich-like BiVO_4 sheets can be attributed to its large surface area over the irregular BiVO_4 particles.

In vitro assessment of activity of graphene silver composite sheets ...

African Journals Online (AJOL)

International Pharmaceutical Abstract, Chemical Abstracts, Embase, Index Copernicus, EBSCO, African. Index Medicus ... was cooled to −5 °C. The excess water was removed under ..... Microwave synthesis of graphene sheets supporting.

Magnetic configurations of the tilted current sheets in magnetotail

Directory of Open Access Journals (Sweden)

C. Shen

2008-11-01

Full Text Available In this research, the geometrical structures of tilted current sheet and tail flapping waves have been analysed based on multiple spacecraft measurements and some features of the tilted current sheets have been made clear for the first time. The geometrical features of the tilted current sheet revealed in this investigation are as follows: (1 The magnetic field lines (MFLs in the tilted current sheet are generally plane curves and the osculating planes in which the MFLs lie are about vertical to the equatorial plane, while the normal of the tilted current sheet leans severely to the dawn or dusk side. (2 The tilted current sheet may become very thin, the half thickness of its neutral sheet is generally much less than the minimum radius of the curvature of the MFLs. (3 In the neutral sheet, the field-aligned current density becomes very large and has a maximum value at the center of the current sheet. (4 In some cases, the current density is a bifurcated one, and the two humps of the current density often superpose two peaks in the gradient of magnetic strength, indicating that the magnetic gradient drift current is possibly responsible for the formation of the two humps of the current density in some tilted current sheets. Tilted current sheets often appear along with tail current sheet flapping waves. It is found that, in the tail flapping current sheets, the minimum curvature radius of the MFLs in the current sheet is rather large with values around 1 RE, while the neutral sheet may be very thin, with its half thickness being several tenths of RE. During the flapping waves, the current sheet is tilted substantially, and the maximum tilt angle is generally larger than 45°. The phase velocities of these flapping waves are several tens km/s, while their periods and wavelengths are several tens of minutes, and several earth radii, respectively. These tail flapping events generally last several hours and occur during quiet periods or periods of

Student generated assignments about electrical circuits in a computer simulation

NARCIS (Netherlands)

Vreman-de Olde, Cornelise; de Jong, Anthonius J.M.

2004-01-01

In this study we investigated the design of assignments by students as a knowledge-generating activity. Students were required to design assignments for 'other students' in a computer simulation environment about electrical circuits. Assignments consisted of a question, alternatives, and feedback on

Different bulk and active bacterial communities in cryoconite from the margin and interior of the Greenland ice sheet

DEFF Research Database (Denmark)

Stibal, Marek; Schostag, Morten; Cameron, Karen A.

2015-01-01

composition of cryoconite over a melt season at two contrasting sites at the margin and in the interior of the Greenland ice sheet, using sequence analysis and quantitative polymerase chain reaction of coextracted 16S rDNA and rRNA. Significant differences were found between bulk (rDNA) and potentially active...

Effect of microalloying with rare-earth on recrystallization behaviour and damping properties of Mg sheets

International Nuclear Information System (INIS)

Ma, Ning; Peng, Qiuming; Pan, Junling; Li, Hui; Xiao, Wenlong

2014-01-01

Highlights: • Rare earth additions accelerate recovery, but retard recrystallization. • Internal peak at mediate temperatures corresponds to grain boundary relaxation. • Internal peak at elevated temperature is a recrystallization peak. • Grain size, basal texture and dislocation density affect damping remarkably. - Abstract: The effect of a small amount of rare earth elements (RE: Nd and Dy, 0.5 wt.%) on recrystallization behaviour, microstructural evolution and damping properties of deformed Mg sheets have been investigated. The recrystallization behaviour was analyzed in terms of the Johnson–Mehl–Avrami–Kolmogorov model via the variation of microhardness. The Avrami exponent of pure Mg sheet ranged from 1.02 to 1.16, and it was reduced by adding REs. The acceleration of recovery and retardation of recrystallization were detected by the presence of REs. Three point bending was carried out to assess damping properties. At the temperature of ∼150 °C, the damping peak corresponds to grain boundary relaxation, which was affected by grain size, basal texture and the variation of dislocation density on basal plane. At elevated temperatures, a non-thermal activated peak was mainly dependent upon annealing condition, where its height and temperature were increased by adding REs, assigning to be a recrystallization peak

Principles for designing proteins with cavities formed by curved β sheets

Energy Technology Data Exchange (ETDEWEB)

Marcos, Enrique; Basanta, Benjamin; Chidyausiku, Tamuka M.; Tang, Yuefeng; Oberdorfer, Gustav; Liu, Gaohua; Swapna, G. V. T.; Guan, Rongjin; Silva, Daniel-Adriano; Dou, Jiayi; Pereira, Jose Henrique; Xiao, Rong; Sankaran, Banumathi; Zwart, Peter H.; Montelione, Gaetano T.; Baker, David

2017-01-12

Active sites and ligand-binding cavities in native proteins are often formed by curved β sheets, and the ability to control β-sheet curvature would allow design of binding proteins with cavities customized to specific ligands. Toward this end, we investigated the mechanisms controlling β-sheet curvature by studying the geometry of β sheets in naturally occurring protein structures and folding simulations. The principles emerging from this analysis were used to design, de novo, a series of proteins with curved β sheets topped with α helices. Nuclear magnetic resonance and crystal structures of the designs closely match the computational models, showing that β-sheet curvature can be controlled with atomic-level accuracy. Our approach enables the design of proteins with cavities and provides a route to custom design ligand-binding and catalytic sites.

Incorporation of ice sheet models into an Earth system model: Focus on methodology of coupling

Science.gov (United States)

Rybak, Oleg; Volodin, Evgeny; Morozova, Polina; Nevecherja, Artiom

2018-03-01

Elaboration of a modern Earth system model (ESM) requires incorporation of ice sheet dynamics. Coupling of an ice sheet model (ICM) to an AOGCM is complicated by essential differences in spatial and temporal scales of cryospheric, atmospheric and oceanic components. To overcome this difficulty, we apply two different approaches for the incorporation of ice sheets into an ESM. Coupling of the Antarctic ice sheet model (AISM) to the AOGCM is accomplished via using procedures of resampling, interpolation and assigning to the AISM grid points annually averaged meanings of air surface temperature and precipitation fields generated by the AOGCM. Surface melting, which takes place mainly on the margins of the Antarctic peninsula and on ice shelves fringing the continent, is currently ignored. AISM returns anomalies of surface topography back to the AOGCM. To couple the Greenland ice sheet model (GrISM) to the AOGCM, we use a simple buffer energy- and water-balance model (EWBM-G) to account for orographically-driven precipitation and other sub-grid AOGCM-generated quantities. The output of the EWBM-G consists of surface mass balance and air surface temperature to force the GrISM, and freshwater run-off to force thermohaline circulation in the oceanic block of the AOGCM. Because of a rather complex coupling procedure of GrIS compared to AIS, the paper mostly focuses on Greenland.

Synthesis of N-doped microporous carbon via chemical activation of polyindole-modified graphene oxide sheets for selective carbon dioxide adsorption

International Nuclear Information System (INIS)

Saleh, Muhammad; Chandra, Vimlesh; Christian Kemp, K; Kim, Kwang S

2013-01-01

A polyindole-reduced graphene oxide (PIG) hybrid was synthesized by reducing graphene oxide sheets in the presence of polyindole. We have shown PIG as a material for capturing carbon dioxide (CO 2 ). The PIG hybrid was chemically activated at temperatures of 400–800 ° C, which resulted in nitrogen (N)-doped graphene sheets. The N-doped graphene sheets are microporous with an adsorption pore size of 0.6 nm for CO 2 and show a maximum (Brunauer, Emmet and Teller) surface area of 936 m 2 g −1 . The hybrid activated at 600 ° C (PIG6) possesses a surface area of 534 m 2 g −1 and a micropore volume of 0.29 cm 3 g −1 . PIG6 shows a maximum CO 2 adsorption capacity of 3.0 mmol g −1 at 25 ° C and 1 atm. This high CO 2 uptake is due to the highly microporous character of the material and its N content. The material retains its original adsorption capacity on recycling even after 10 cycles (within experimental error). PIG6 also shows high adsorption selectivity ratios for CO 2 over N 2 , CH 4 and H 2 of 23, 4 and 85 at 25 ° C, respectively. (paper)

Relation between current sheets and vortex sheets in stationary incompressible MHD

Directory of Open Access Journals (Sweden)

D. H. Nickeler

2012-03-01

Full Text Available Magnetohydrodynamic configurations with strong localized current concentrations and vortices play an important role in the dissipation of energy in space and astrophysical plasma. Within this work we investigate the relation between current sheets and vortex sheets in incompressible, stationary equilibria. For this approach it is helpful that the similar mathematical structure of magnetohydrostatics and stationary incompressible hydrodynamics allows us to transform static equilibria into stationary ones. The main control function for such a transformation is the profile of the Alfvén-Mach number MA, which is always constant along magnetic field lines, but can change from one field line to another. In the case of a global constant MA, vortices and electric current concentrations are parallel. More interesting is the nonlinear case, where MA varies perpendicular to the field lines. This is a typical situation at boundary layers like the magnetopause, heliopause, the solar wind flowing around helmet streamers and at the boundary of solar coronal holes. The corresponding current and vortex sheets show in some cases also an alignment, but not in every case. For special density distributions in 2-D, it is possible to have current but no vortex sheets. In 2-D, vortex sheets of field aligned-flows can also exist without strong current sheets, taking the limit of small Alfvén Mach numbers into account. The current sheet can vanish if the Alfvén Mach number is (almost constant and the density gradient is large across some boundary layer. It should be emphasized that the used theory is not only valid for small Alfvén Mach numbers MA MA ≲ 1. Connection to other theoretical approaches and observations and physical effects in space plasmas are presented. Differences in the various aspects of theoretical investigations of current sheets and vortex sheets are given.

An ice sheet model validation framework for the Greenland ice sheet

Science.gov (United States)

Price, Stephen F.; Hoffman, Matthew J.; Bonin, Jennifer A.; Howat, Ian M.; Neumann, Thomas; Saba, Jack; Tezaur, Irina; Guerber, Jeffrey; Chambers, Don P.; Evans, Katherine J.; Kennedy, Joseph H.; Lenaerts, Jan; Lipscomb, William H.; Perego, Mauro; Salinger, Andrew G.; Tuminaro, Raymond S.; van den Broeke, Michiel R.; Nowicki, Sophie M. J.

2017-01-01

We propose a new ice sheet model validation framework - the Cryospheric Model Comparison Tool (CmCt) - that takes advantage of ice sheet altimetry and gravimetry observations collected over the past several decades and is applied here to modeling of the Greenland ice sheet. We use realistic simulations performed with the Community Ice Sheet Model (CISM) along with two idealized, non-dynamic models to demonstrate the framework and its use. Dynamic simulations with CISM are forced from 1991 to 2013, using combinations of reanalysis-based surface mass balance and observations of outlet glacier flux change. We propose and demonstrate qualitative and quantitative metrics for use in evaluating the different model simulations against the observations. We find that the altimetry observations used here are largely ambiguous in terms of their ability to distinguish one simulation from another. Based on basin-scale and whole-ice-sheet-scale metrics, we find that simulations using both idealized conceptual models and dynamic, numerical models provide an equally reasonable representation of the ice sheet surface (mean elevation differences of framework demonstrates that our proposed metrics can distinguish relatively better from relatively worse simulations and that dynamic ice sheet models, when appropriately initialized and forced with the right boundary conditions, demonstrate a predictive skill with respect to observed dynamic changes that have occurred on Greenland over the past few decades. An extensible design will allow for continued use of the CmCt as future altimetry, gravimetry, and other remotely sensed data become available for use in ice sheet model validation.

Active Appearance Segmentation for Intensity Inhomogeneity in Light Sheet Fluorescence Microscopy

DEFF Research Database (Denmark)

Jensen, Casper Bo; Lyksborg, Mark; Hecksher-Sørensen, J.

2016-01-01

inhomogeneities which are often seen in Light Sheet Fluorescence Microscopy (LSFM) images. This robustness is achieved by modelling the appearance of an image as a regularized Normalized Gradient Field (rNGF). We perform two experiments to challenge the model. First it is tested using a repeated leave......Active Appearance Models (AAM) are used for annotating or segmenting shapes in biomedical images. Performance relies heavily on the image data used to train the AAM. In this paper we improve the generalization properties of the model by making it robust to slowly varying spatial intensity......-one-out approach on images with minimal imperfections where the left out images are corrupted by a simulated bias field and segmented using the AAM. Secondly we test the model on LSFM images with common acquisition problems. In both experiments the proposed approach outperforms the often used AAM implementation...

Nuclear accident dosimetry. Revision of emergency data sheets

International Nuclear Information System (INIS)

Delafield, H.J.

1976-09-01

The Emergency Data Sheets on Nuclear Accident Dosimetry have been revealed following the publication of a three part manual on this subject (Delafield, Dennis and Gibson, AERE-R 7485/6/7, 1973). This memo provides an explanation of the action levels adopted for the initial segregation of irradiated persons following a criticality accident, by monitoring the activity of indium foils contained in personnel dosimeters and the induced body sodium activity. The data sheets are given as an Appendix. They provide basic information on; the segregation of irradiated persons, the estimation of radiation exposure, and the assessment of personnel γ-ray and neutron doses. (author)

Chlamydia - CDC Fact Sheet

Science.gov (United States)

... Archive STDs Home Page Bacterial Vaginosis (BV) Chlamydia Gonorrhea Genital Herpes Hepatitis HIV/AIDS & STDs Human Papillomavirus ( ... sheet Pelvic Inflammatory Disease (PID) – CDC fact sheet Gonorrhea – CDC fact sheet STDs Home Page Bacterial Vaginosis ( ...

Characterization of Tensile Mechanical Behavior of MSCs/PLCL Hybrid Layered Sheet

Directory of Open Access Journals (Sweden)

Azizah Intan Pangesty

2016-06-01

Full Text Available A layered construct was developed by combining a porous polymer sheet and a cell sheet as a tissue engineered vascular patch. The primary objective of this study is to investigate the influence of mesenchymal stem cells (MSCs sheet on the tensile mechanical properties of porous poly-(l-lactide-co-ε-caprolactone (PLCL sheet. The porous PLCL sheet was fabricated by the solid-liquid phase separation method and the following freeze-drying method. The MSCs sheet, prepared by the temperature-responsive dish, was then layered on the top of the PLCL sheet and cultured for 2 weeks. During the in vitro study, cellular properties such as cell infiltration, spreading and proliferation were evaluated. Tensile test of the layered construct was performed periodically to characterize the tensile mechanical behavior. The tensile properties were then correlated with the cellular properties to understand the effect of MSCs sheet on the variation of the mechanical behavior during the in vitro study. It was found that MSCs from the cell sheet were able to migrate into the PLCL sheet and actively proliferated into the porous structure then formed a new layer of MSCs on the opposite surface of the PLCL sheet. Mechanical evaluation revealed that the PLCL sheet with MSCs showed enhancement of tensile strength and strain energy density at the first week of culture which is characterized as the effect of MSCs proliferation and its infiltration into the porous structure of the PLCL sheet. New technique was presented to develop tissue engineered patch by combining MSCs sheet and porous PLCL sheet, and it is expected that the layered patch may prolong biomechanical stability when implanted in vivo.

Photocatalytic perfermance of sandwich-like BiVO{sub 4} sheets by microwave assisted synthesis

Energy Technology Data Exchange (ETDEWEB)

Liu, Suqin, E-mail: liusuqin888@126.com [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China); Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices, Xiangyang 441053 (China); Tang, Huiling; Zhou, Huan [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China); Dai, Gaopeng, E-mail: dgp2000@126.com [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China); Wang, Wanqiang [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China)

2017-01-01

Graphical abstract: Sandwich-like BiVO{sub 4} sheets were successfully synthesized via a facile microwave-assisted method. The as-prepared samples exhibit a high activity for the degradation of methyl orange under visible light irradiation. - Highlights: • Sandwich-like BiVO{sub 4} sheets were synthesized by a facile microwave-assisted method. • The presence of PEG-10000 plays a critical role in the formation of BiVO{sub 4} sheets. • Ostwald ripening is the primary driving force for the formation of sandwich-like BiVO{sub 4}. • The sandwich-like BiVO{sub 4} sheets exhibit a high visible-light photocatalytic activity. - Abstract: Sandwich-like BiVO{sub 4} sheets were successfully synthesized in an aqueous solution containing bismuth nitrate, ammonium metavanadate and polyethylene glycol with a molecular weight of 10,000 (PEG-10000) using a facile microwave-assisted method. The as-prepared samples were characterized by scanning electron microscopy, N{sub 2} adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectroscopy. The results show that the presence of PEG-10000 plays a critical role in the formation of BiVO{sub 4} sheets, and Ostwald ripening is the primary driving force for the formation of sandwich-like structures. The sandwich-like BiVO{sub 4} sheets exhibit a high activity for the degradation of methyl orange under visible light irradiation (λ ≥ 420 nm). The enhancement of photocatalytic activity of sandwich-like BiVO{sub 4} sheets can be attributed to its large surface area over the irregular BiVO{sub 4} particles.

Laminin-521 Promotes Rat Bone Marrow Mesenchymal Stem Cell Sheet Formation on Light-Induced Cell Sheet Technology

Directory of Open Access Journals (Sweden)

Zhiwei Jiang

2017-01-01

Full Text Available Rat bone marrow mesenchymal stem cell sheets (rBMSC sheets are attractive for cell-based tissue engineering. However, methods of culturing rBMSC sheets are critically limited. In order to obtain intact rBMSC sheets, a light-induced cell sheet method was used in this study. TiO2 nanodot films were coated with (TL or without (TN laminin-521. We investigated the effects of laminin-521 on rBMSCs during cell sheet culturing. The fabricated rBMSC sheets were subsequently assessed to study cell sheet viability, reattachment ability, cell sheet thickness, collagen type I deposition, and multilineage potential. The results showed that laminin-521 could promote the formation of rBMSC sheets with good viability under hyperconfluent conditions. Cell sheet thickness increased from an initial 26.7 ± 1.5 μm (day 5 up to 47.7 ± 3.0 μm (day 10. Moreover, rBMSC sheets maintained their potential of osteogenic, adipogenic, and chondrogenic differentiation. This study provides a new strategy to obtain rBMSC sheets using light-induced cell sheet technology.

Ice Sheet Model Intercomparison Project (ISMIP6) contribution to CMIP6

NARCIS (Netherlands)

Nowicki, Sophie M J; Payne, Anthony; Larour, Eric; Seroussi, Helene; Goelzer, Heiko|info:eu-repo/dai/nl/412549123; Lipscomb, William; Gregory, Jonathan; Abe-Ouchi, Ayako; Shepherd, Andrew

2016-01-01

Reducing the uncertainty in the past, present, and future contribution of ice sheets to sea-level change requires a coordinated effort between the climate and glaciology communities. The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) is the primary activity within the Coupled Model

Indoor external dose rates due to decorative sheet stone

Energy Technology Data Exchange (ETDEWEB)

Lu, C.H.; Sheu, R.D.; Jiang, S.H. [Dept. of Engineering and System Science, National Tsing Hua Univ., Hsinchu (Taiwan)

2002-03-01

The specific activities in decorative sheet stone made of granite or marble were measured, whereby the absolute peak efficiency of the HPGe detectors employed in the measurements for the sheet-stone sample was determined using the semi-empirical method. The spatial distribution for the indoor external dose rates due to the radionuclides present in the decorative sheet stone used to clad the floor and the four walls of a standard room was calculated using a three-dimensional point kernel computer code. It was found that the spatial distribution for the indoor dose rates was complex and non-uniform, which represents a difference in relation to the results of earlier studies. (orig.)

Indoor external dose rates due to decorative sheet stone

International Nuclear Information System (INIS)

Lu, C.H.; Sheu, R.D.; Jiang, S.H.

2002-01-01

The specific activities in decorative sheet stone made of granite or marble were measured, whereby the absolute peak efficiency of the HPGe detectors employed in the measurements for the sheet-stone sample was determined using the semi-empirical method. The spatial distribution for the indoor external dose rates due to the radionuclides present in the decorative sheet stone used to clad the floor and the four walls of a standard room was calculated using a three-dimensional point kernel computer code. It was found that the spatial distribution for the indoor dose rates was complex and non-uniform, which represents a difference in relation to the results of earlier studies. (orig.)

Nonlinear dynamics of thin current sheets

International Nuclear Information System (INIS)

Daughton, William

2002-01-01

Observations indicate that the current sheet in the Earth's geomagnetic tail may compress to a thickness comparable to an ion gyro-radius prior to substorm onset. In recent years, there has been considerable controversy regarding the kinetic stability of these thin structures. In particular, the growth rate of the kink instability and its relevance to magnetotail dynamics is still being debated. In this work, a series of fully kinetic particle-in-cell simulations are performed for a thin Harris sheet. The ion to electron mass ratio is varied between m i /m e =4→400 and careful comparisons are made with a formally exact approach to the linear Vlasov theory. At low mass ratio m i /m e <64, the simulations are in excellent agreement with the linear theory, but at high mass ratio the kink instability is observed to grow more rapidly in the kinetic simulations than predicted by theory. The resolution to this apparent discrepancy involves the lower hybrid instability which is active on the edge of the sheet and rapidly produces nonlinear modifications to the initial equilibrium. The nature of this nonlinear deformation is characterized and a simple model is proposed to explain the physics. After the growth and saturation of the lower hybrid fluctuations, the deformed current sheet is similar in structure to a Harris equilibrium with an additional background population. This may explain the large growth rate of the kink instability at later times, since this type of modification to the Harris sheet has been shown to greatly enhance the growth rate of the kink mode

Superfund fact sheet: The remedial program. Fact sheet

International Nuclear Information System (INIS)

1992-09-01

The fact sheet describes what various actions the EPA can take to clean up hazardous wastes sites. Explanations of how the criteria for environmental and public health risk assessment are determined and the role of state and local governments in site remediation are given. The fact sheet is one in a series providing reference information about Superfund issues and is intended for readers with no formal scientific training

Radiation protecting sheet

International Nuclear Information System (INIS)

Makiguchi, Hiroshi.

1989-01-01

As protection sheets used in radioactivity administration areas, a thermoplastic polyurethane composition sheet with a thickness of less 0.5 mm, solid content (ash) of less than 5% and a shore D hardness of less than 60 is used. A composite sheet with thickness of less than 0.5 mm laminated or coated with such a thermoplastic polyurethane composition as a surface layer and the thermoplastic polyurethane composition sheet applied with secondary fabrication are used. This can satisfy all of the required properties, such as draping property, abrasion resistance, high breaking strength, necking resistance, endurance strength, as well as chemical resistance and easy burnability in burning furnace. Further, by forming uneveness on the surface by means of embossing, etc. safety problems such as slippage during operation and walking can be overcome. (T.M.)

Protein secondary structure assignment revisited: a detailed analysis of different assignment methods

Directory of Open Access Journals (Sweden)

de Brevern Alexandre G

2005-09-01

Full Text Available Abstract Background A number of methods are now available to perform automatic assignment of periodic secondary structures from atomic coordinates, based on different characteristics of the secondary structures. In general these methods exhibit a broad consensus as to the location of most helix and strand core segments in protein structures. However the termini of the segments are often ill-defined and it is difficult to decide unambiguously which residues at the edge of the segments have to be included. In addition, there is a "twilight zone" where secondary structure segments depart significantly from the idealized models of Pauling and Corey. For these segments, one has to decide whether the observed structural variations are merely distorsions or whether they constitute a break in the secondary structure. Methods To address these problems, we have developed a method for secondary structure assignment, called KAKSI. Assignments made by KAKSI are compared with assignments given by DSSP, STRIDE, XTLSSTR, PSEA and SECSTR, as well as secondary structures found in PDB files, on 4 datasets (X-ray structures with different resolution range, NMR structures. Results A detailed comparison of KAKSI assignments with those of STRIDE and PSEA reveals that KAKSI assigns slightly longer helices and strands than STRIDE in case of one-to-one correspondence between the segments. However, KAKSI tends also to favor the assignment of several short helices when STRIDE and PSEA assign longer, kinked, helices. Helices assigned by KAKSI have geometrical characteristics close to those described in the PDB. They are more linear than helices assigned by other methods. The same tendency to split long segments is observed for strands, although less systematically. We present a number of cases of secondary structure assignments that illustrate this behavior. Conclusion Our method provides valuable assignments which favor the regularity of secondary structure segments.

Mapping whole-brain activity with cellular resolution by light-sheet microscopy and high-throughput image analysis (Conference Presentation)

Science.gov (United States)

Silvestri, Ludovico; Rudinskiy, Nikita; Paciscopi, Marco; Müllenbroich, Marie Caroline; Costantini, Irene; Sacconi, Leonardo; Frasconi, Paolo; Hyman, Bradley T.; Pavone, Francesco S.

2016-03-01

Mapping neuronal activity patterns across the whole brain with cellular resolution is a challenging task for state-of-the-art imaging methods. Indeed, despite a number of technological efforts, quantitative cellular-resolution activation maps of the whole brain have not yet been obtained. Many techniques are limited by coarse resolution or by a narrow field of view. High-throughput imaging methods, such as light sheet microscopy, can be used to image large specimens with high resolution and in reasonable times. However, the bottleneck is then moved from image acquisition to image analysis, since many TeraBytes of data have to be processed to extract meaningful information. Here, we present a full experimental pipeline to quantify neuronal activity in the entire mouse brain with cellular resolution, based on a combination of genetics, optics and computer science. We used a transgenic mouse strain (Arc-dVenus mouse) in which neurons which have been active in the last hours before brain fixation are fluorescently labelled. Samples were cleared with CLARITY and imaged with a custom-made confocal light sheet microscope. To perform an automatic localization of fluorescent cells on the large images produced, we used a novel computational approach called semantic deconvolution. The combined approach presented here allows quantifying the amount of Arc-expressing neurons throughout the whole mouse brain. When applied to cohorts of mice subject to different stimuli and/or environmental conditions, this method helps finding correlations in activity between different neuronal populations, opening the possibility to infer a sort of brain-wide 'functional connectivity' with cellular resolution.

Automobile sheet metal part production with incremental sheet forming

Directory of Open Access Journals (Sweden)

İsmail DURGUN

2016-02-01

Full Text Available Nowadays, effect of global warming is increasing drastically so it leads to increased interest on energy efficiency and sustainable production methods. As a result of adverse conditions, national and international project platforms, OEMs (Original Equipment Manufacturers, SMEs (Small and Mid-size Manufacturers perform many studies or improve existing methodologies in scope of advanced manufacturing techniques. In this study, advanced manufacturing and sustainable production method "Incremental Sheet Metal Forming (ISF" was used for sheet metal forming process. A vehicle fender was manufactured with or without die by using different toolpath strategies and die sets. At the end of the study, Results have been investigated under the influence of method and parameters used.Keywords: Template incremental sheet metal, Metal forming

The quantitative inspection of iron aluminide green sheet using transient thermography

International Nuclear Information System (INIS)

Watkins, Michael L.; Hinders, Mark K.; Scorey, Clive; Winfree, William

1999-01-01

The recent development of manufacturing techniques for the fabrication of thin iron aluminide, FeAl, sheet requires advanced quantitative methods for on-line inspection. An understanding of the mechanisms responsible for flaws and the development of appropriate flaw detection methods are key elements in an effective quality management system. The first step in the fabrication of thin FeAl alloy sheet is the formation of a green sheet, either by cold rolling or tape casting FeAl powder mixed with organic binding agents. The finished sheet is obtained using a series of process steps involving binder elimination, densification, sintering, and annealing. Non-uniformities within the green sheet are the major contributor to material failure in subsequent sheet processing and the production of non-conforming finished sheet. Previous work has demonstrated the advantages of using active thermography to detect the flaws and heterogeneity within green powder composites (1)(2)(3). The production environment and physical characteristics of these composites provide for unique challenges in developing a rapid nondestructive inspection capability. Thermography is non-contact and minimizes the potential damage to the fragile green sheet. Limited access to the material also demands a one-sided inspection technique. In this paper, we will describe the application of thermography for 100% on-line inspection within an industrial process. This approach is cost competitive with alternative technologies, such as x-ray imaging systems, and provides the required sensitivity to the variations in material composition. The formation of green sheet flaws and their transformation into defects within intermediate and finished sheet products will be described. A green sheet conformance criterion will be presented which would significantly reduce the probability of processing poor quality green sheet which contributes to higher waste and inferior bulk alloy sheet

A new perspective on beta-sheet structures using vibrational Raman optical activity: From poly(L-lysine) to the prion protein

DEFF Research Database (Denmark)

McColl, L.H.; Blanch, E.W.; Gill, A.C.

2003-01-01

-sheet poly(L-lysine) contains up-and-down antiparallel beta-sheets based on the hairpin motif. The ROA spectrum of beta-sheet poly(L-lysine) was compared with ROA data on a number of native proteins containing different types of beta-sheet. Amide I and amide II ROA band patterns observed in beta-sheet poly(L-ly...

Composition and plasma properties of the plasma sheet in the Earth's magnetotail

International Nuclear Information System (INIS)

Orsini, S.; Altwegg, K.; Balsiger, H.

1986-01-01

A statistical study of the plasma sheet properties, based on 300 h of data from the ISEE-1 Ion Composition Experiment, yiels a description of H + and He ++ densities and temperatures as functions of magnetospheric substorm activity and geocentric distance. The H + and He ++ temperatures are found to be well correlated, such that a ratio T(He ++ )/T(H + ) = 2.7±0.1 is typical. However, linear-regression analysis typically yields a nonvanishing T(He ++ ) in the limit T(H + ) #-> # 0, a limit that is approached through the addition of cold ionospheric H + to the plasma sheet during active periods. The plasma sheet proton temperature T(H + ) varies inversely with geocentric distance, and the radial gradient of T(H + ) increases with increasing activity index AE. The density ratio N (He ++ )/N(H + ) increases with geocentric distance, irrespective of AE

Intraoperative use of a reflective blanket (Sirius rescue sheet) for temperature management in dogs less than 10 kg.

Science.gov (United States)

Tünsmeyer, J; Bojarski, I; Nolte, I; Kramer, S

2009-07-01

To compare the effects of the Sirius rescue sheet with gel pads versus gel pads alone on intraoperative body temperature in dogs less than 10 kg. Forty small breed dogs undergoing elective surgical procedures were randomly assigned to two groups. One group was intraoperatively laid on warmed gel pads, and the other group was additionally wrapped in a Sirius rescue sheet. Oesophageal body temperature was determined every 10 minutes and compared between groups. Temperature of gel pads was measured preoperatively and postoperatively to compare heat loss of the gel pads between groups. The body temperature of dogs wrapped with the Sirius rescue sheet increased intraoperatively. In dogs just lying on warmed gel pads, a decrease in mean body temperature was revealed and mean body temperatures differed between groups after 40 minutes. Extent of heat loss from the gel pads did not differ between the groups. The Sirius rescue sheet, used in addition to warmed gel pads, led to higher intraoperative body temperatures in small breed dogs undergoing surgical procedures to the extremities and the head. The cost-effectiveness and ease of handling make this a useful addition to clinical practice.

Effect of material flow on joint strength in activation spot joining of Al alloy and steel sheets

International Nuclear Information System (INIS)

Watanabe, Goro; Yogo, Yasuhiro; Takao, Hisaaki

2014-01-01

A new joining method for dissimilar metal sheets was developed where a rotated consumable rod of Al alloy is pressed onto an Al alloy sheet at the part overlapped with a mild steel sheet. The metal flow in the joining region is increased by the through-hole in the Al sheet and consumable Al rod. The rod creates the joint interface and pads out of the thinly joined parts through pressing. This produces a higher joint strength than that of conventional friction stir spot welding. Measurements of the joint interface showed the presence of a 5-10 nm thick amorphous layer consisting of Al and Mg oxides

Geometry of thin liquid sheet flows

Science.gov (United States)

Chubb, Donald L.; Calfo, Frederick D.; Mcconley, Marc W.; Mcmaster, Matthew S.; Afjeh, Abdollah A.

1994-01-01

Incompresible, thin sheet flows have been of research interest for many years. Those studies were mainly concerned with the stability of the flow in a surrounding gas. Squire was the first to carry out a linear, invicid stability analysis of sheet flow in air and compare the results with experiment. Dombrowski and Fraser did an experimental study of the disintegration of sheet flows using several viscous liquids. They also detected the formulation of holes in their sheet flows. Hagerty and Shea carried out an inviscid stability analysis and calculated growth rates with experimental values. They compared their calculated growth rates with experimental values. Taylor studied extensively the stability of thin liquid sheets both theoretically and experimentally. He showed that thin sheets in a vacuum are stable. Brown experimentally investigated thin liquid sheet flows as a method of application of thin films. Clark and Dumbrowski carried out second-order stability analysis for invicid sheet flows. Lin introduced viscosity into the linear stability analysis of thin sheet flows in a vacuum. Mansour and Chigier conducted an experimental study of the breakup of a sheet flow surrounded by high-speed air. Lin et al. did a linear stability analysis that included viscosity and a surrounding gas. Rangel and Sirignano carried out both a linear and nonlinear invisid stability analysis that applies for any density ratio between the sheet liquid and the surrounding gas. Now there is renewed interest in sheet flows because of their possible application as low mass radiating surfaces. The objective of this study is to investigate the fluid dynamics of sheet flows that are of interest for a space radiator system. Analytical expressions that govern the sheet geometry are compared with experimental results. Since a space radiator will operate in a vacuum, the analysis does not include any drag force on the sheet flow.

Large-scale Modeling of the Greenland Ice Sheet on Long Timescales

DEFF Research Database (Denmark)

Solgaard, Anne Munck

is investigated as well as its early history. The studies are performed using an ice-sheet model in combination with relevant forcing from observed and modeled climate. Changes in ice-sheet geometry influences atmospheric flow (and vice versa) hereby changing the forcing patterns. Changes in the overall climate...... and climate model is included shows, however, that a Föhn effect is activated and hereby increasing temperatures inland and inhibiting further ice-sheet expansion into the interior. This indicates that colder than present temperatures are needed in order for the ice sheet to regrow to the current geometry....... Accordingto this hypothesis, two stages of uplift since the Late Miocene lead to the present-day topography. The results of the ice-sheet simulations show geometries in line with geologicobservations through the period, and it is found that the uplift events enhance the effect of the climatic deterioration...

Characterization of the behaviour of electro-galvanised steel sheets in terms of corrosion

International Nuclear Information System (INIS)

Finoly, Guylene

1992-01-01

This research thesis reports the development of a test method for the characterization of the behaviour of electro-galvanised steel sheets (i.e. zinc coated steel sheets as those used in the automotive industry) with respect to corrosion, and the definition of a classification of these materials with respect to their surface activity. After an overview of the different existing methods of determination of corrosion rate, the author reports the development of an experimental device adapted to the electrochemical study of electro-galvanised sheets, i.e. adapted to their low thickness (0,7 mm) and coating characteristics (10 μm thick). This device is then used in the case of solid zinc. The authors reports the study of the behaviour of sheets in a NaCl solution in order to meet industrial conditions used to activate the surface before the phosphate conversion process which aims at ensuring paint adherence. A test is proposed and validated by comparison with other electrochemical or chemical methods, and used to study the behaviour of electro-galvanised sheets submitted to a phosphate conversion coating process [fr

Hanford Site Treated Effluent Disposal Facility process flow sheet

International Nuclear Information System (INIS)

Bendixsen, R.B.

1993-04-01

This report presents a novel method of using precipitation, destruction and recycle factors to prepare a process flow sheet. The 300 Area Treated Effluent Disposal Facility (TEDF) will treat process sewer waste water from the 300 Area of the Hanford Site, located near Richland, Washington, and discharge a permittable effluent flow into the Columbia River. When completed and operating, the TEDF effluent water flow will meet or exceed water quality standards for the 300 Area process sewer effluents. A preliminary safety analysis document (PSAD), a preconstruction requirement, needed a process flow sheet detailing the concentrations of radionuclides, inorganics and organics throughout the process, including the effluents, and providing estimates of stream flow quantities, activities, composition, and properties (i.e. temperature, pressure, specific gravity, pH and heat transfer rates). As the facility begins to operate, data from process samples can be used to provide better estimates of the factors, the factors can be entered into the flow sheet and the flow sheet will estimate more accurate steady state concentrations for the components. This report shows how the factors were developed and how they were used in developing a flow sheet to estimate component concentrations for the process flows. The report concludes with how TEDF sample data can improve the ability of the flow sheet to accurately predict concentrations of components in the process

Assignment strategies in homonuclear three-dimensional 1H NMR spectra of proteins

International Nuclear Information System (INIS)

Vuister, G.W.; Boelens, R.; Padilla, A.; Kleywegt, G.J.; Kaptein, R.

1990-01-01

The increase in dimensionality of three-dimensional (3D) NMR greatly enhances the spectral resolution in comparison to 2D NMR. It alleviates the problem of resonance overlap and may extend the range of molecules amenable to structure determination by high-resolution NMR spectroscopy. Here, the authors present strategies for the assignment of protein resonances from homonuclear nonselective 3D NOE-HOHAHA spectra. A notation for connectivities between protons, corresponding to cross peaks in 3D spectra, is introduced. They show how spin systems can be identified by tracing cross-peak patterns in cross sections perpendicular to the three frequency axes. The observable 3D sequential connectivities in proteins are tabulated, and estimates for the relative intensities of the corresponding cross peaks are given for α-helical and β-sheet conformations. Intensities of the cross peaks in the 3D spectrum of pike III paravalbumin follow the predictions. The sequential-assignment procedure is illustrated for loop regions, extended and α-helical conformations for the residues Ala 54-Leu 63 of paravalbumin. NOEs that were not previously identified in 2D spectra of paravalbumin due to overlap are found

Grouping puts figure-ground assignment in context by constraining propagation of edge assignment.

Science.gov (United States)

Brooks, Joseph L; Brook, Joseph L; Driver, Jon

2010-05-01

Figure-ground organization involves the assignment of edges to a figural shape on one or the other side of each dividing edge. Established visual cues for edge assignment primarily concern relatively local rather than contextual factors. In the present article, we show that an assignment for a locally unbiased edge can be affected by an assignment of a remote contextual edge that has its own locally biased assignment. We find that such propagation of edge assignment from the biased remote context occurs only when the biased and unbiased edges are grouped. This new principle, whereby grouping constrains the propagation of figural edge assignment, emerges from both subjective reports and an objective short-term edge-matching task. It generalizes from moving displays involving grouping by common fate and collinearity, to static displays with grouping by similarity of edge-contrast polarity, or apparent occlusion. Our results identify a new contextual influence on edge assignment. They also identify a new mechanistic relation between grouping and figure-ground processes, whereby grouping between remote elements can constrain the propagation of edge assignment between those elements. Supplemental materials for this article may be downloaded from http://app.psychonomic-journals.org/content/supplemental.

FLEET ASSIGNMENT MODELLING

Directory of Open Access Journals (Sweden)

2016-01-01

Full Text Available The article is devoted to the airline scheduling process and methods of its modeling. This article describes the main stages of airline scheduling process (scheduling, fleet assignment, revenue management, operations, their features and interactions. The main part of scheduling process is fleet assignment. The optimal solution of the fleet assignment problem enables airlines to increase their incomes up to 3 % due to quality improving of connections and execution of the planned number of flights operated by less number of aircraft than usual or planned earlier. Fleet assignment of scheduling process is examined and Conventional Leg-Based Fleet Assignment Model is analyzed. Finally strong and weak aspects of the model (SWOT are released and applied. The article gives a critical analysis of FAM model, with the purpose of identi- fying possible options and constraints of its use (for example, in cases of short-term and long-term planning, changing the schedule or replacing the aircraft, as well as possible ways to improve the model.

Effects of electromechanical resonance on photocatalytic reduction of the free-hanging graphene oxide sheets

International Nuclear Information System (INIS)

Ostovari, F.; Abdi, Y.; Darbari, S.; Ghasemi, F.

2013-01-01

In this report we present a simple, low-temperature method which is compatible with standard technology, to achieve graphene-based devices in large quantity. In this approach we take advantage of photocatalytic behavior of TiO 2 to achieve photocatalytic reduction of chemically synthesized graphene oxide (GO) sheets. TiO 2 nanoparticles have been deposited on GO sheets hanging from Au/SiO 2 /Si interdigital electrodes to realize TiO 2 /GO heterostructures. We investigated photocatalytic activity of TiO 2 nanoparticles in the presence of UV-illumination, to reduce the GO sheets. Based on the Raman spectroscopy, the photocatalytic activity of TiO 2 nanoparticles resulted in a decrease in the number of C–O bonds. Electrical measurements show that graphene sheets with the controlled electrical conductivity were obtained, so that higher illumination time led to higher conductivity and better reduction of GO sheets. Also, strain-induced photocatalytic reduction of the GO sheets has been investigated by their electrical characteristics. It has been shown for the first time that the electromechanical-induced strain enhances the photocatalytic behavior of the fabricated TiO 2 /GO heterostructure significantly.

Effects of electromechanical resonance on photocatalytic reduction of the free-hanging graphene oxide sheets

Energy Technology Data Exchange (ETDEWEB)

Ostovari, F.; Abdi, Y., E-mail: y.abdi@ut.ac.ir [University of Tehran, Nano-Physics Research Laboratory, Department of Physics (Iran, Islamic Republic of); Darbari, S. [Tarbiat Modarres University (Iran, Islamic Republic of); Ghasemi, F. [University of Tehran, Nano-Physics Research Laboratory, Department of Physics (Iran, Islamic Republic of)

2013-04-15

In this report we present a simple, low-temperature method which is compatible with standard technology, to achieve graphene-based devices in large quantity. In this approach we take advantage of photocatalytic behavior of TiO{sub 2} to achieve photocatalytic reduction of chemically synthesized graphene oxide (GO) sheets. TiO{sub 2} nanoparticles have been deposited on GO sheets hanging from Au/SiO{sub 2}/Si interdigital electrodes to realize TiO{sub 2}/GO heterostructures. We investigated photocatalytic activity of TiO{sub 2} nanoparticles in the presence of UV-illumination, to reduce the GO sheets. Based on the Raman spectroscopy, the photocatalytic activity of TiO{sub 2} nanoparticles resulted in a decrease in the number of C-O bonds. Electrical measurements show that graphene sheets with the controlled electrical conductivity were obtained, so that higher illumination time led to higher conductivity and better reduction of GO sheets. Also, strain-induced photocatalytic reduction of the GO sheets has been investigated by their electrical characteristics. It has been shown for the first time that the electromechanical-induced strain enhances the photocatalytic behavior of the fabricated TiO{sub 2}/GO heterostructure significantly.

Best Management Practice, Fact Sheet 2. Sheet Flow to Open Space

OpenAIRE

Sample, David; Doumar, Lia

2013-01-01

This publication explains what sheet flow to open space is, where and how it is used, their limitations, routine and nonroutine maintenance, expected costs, and a glossary of terms. This fact sheet is one of a 15-part series on urban stormwater management practices.

Nonadiabatic heating of the central plasma sheet at substorm onset

International Nuclear Information System (INIS)

Huang, C.Y.; Frank, L.A.; Rostoker, G.; Fennell, J.; Mitchell, D.G.

1992-01-01

Heating events in the plasma sheet boundary layer and central plasma sheet are found to occur at the onset of expansive phase activity. The main effect is a dramatic increase in plasma temperature, coincident with a partial dipolarization of the magnetic field. Fluxes of energetic particles increase without dispersion during these events which occur at all radial distances up to 23 R E , the apogee of the ISEIE spacecraft. A major difference between these heating events and those observed at geosynchronous distances lies in the heating mechanism which is nonadiabatic beyond 10 R E but may be adiabatic closer to Earth. The energy required to account for the increase in plasma thermal energy is comparable with that required for Joule heating of the ionosphere. The plasma sheet must be considered as a major sink in the energy balance of substorm. The authors estimate lobe magnetic pressures during these events. Changes in lobe pressure are generally not correlated with onsets or intensifications of expansive phase activity

LOW POWER RACE-FREE STATE ASSIGNMENT OF AN ASYNGHRONOUS AUTOMATON

Directory of Open Access Journals (Sweden)

Yu. V. Pottosin

2015-01-01

Full Text Available The problem of a race free state assignment of an asynchronous automaton is considered. A method for the state assignment is suggested that provides the minimization of the number and theswitching activity of the memory elements along with the elimination of the critical races betweenthem.

ASYMMETRIC SUNSPOT ACTIVITY AND THE SOUTHWARD DISPLACEMENT OF THE HELIOSPHERIC CURRENT SHEET

International Nuclear Information System (INIS)

Wang, Y.-M.; Robbrecht, E.

2011-01-01

Observations of the interplanetary magnetic field (IMF) have suggested a statistical tendency for the heliospheric current sheet (HCS) to be shifted a few degrees southward of the heliographic equator during the period 1965-2010, particularly in the years near sunspot minimum. Using potential-field source-surface extrapolations and photospheric flux-transport simulations, we demonstrate that this southward displacement follows from Joy's law and the observed hemispheric asymmetry in the sunspot numbers, with activity being stronger in the southern (northern) hemisphere during the declining (rising) phase of cycles 20-23. The hemispheric asymmetry gives rise to an axisymmetric quadrupole field, whose equatorial zone has the sign of the leading-polarity flux in the dominant hemisphere; during the last four cycles, the polarity of the IMF around the equator thus tended to match that of the north polar field both before and after polar field reversal. However, large fluctuations are introduced by the nonaxisymmetric field components, which depend on the longitudinal distribution of sunspot activity in either hemisphere. Consistent with this model, the HCS showed an average northward displacement during cycle 19, when the 'usual' alternation was reversed and the northern hemisphere became far more active than the southern hemisphere during the declining phase of the cycle. We propose a new method for determining the north-south displacement of the HCS from coronal streamer observations.

Carbon sheet pumping

International Nuclear Information System (INIS)

Ohyabu, N.; Sagara, A.; Kawamura, T.; Motojima, O.; Ono, T.

1993-07-01

A new hydrogen pumping scheme has been proposed which controls recycling of the particles for significant improvement of the energy confinement in toroidal magnetic fusion devices. In this scheme, a part of the vacuum vessel surface near the divertor is covered with carbon sheets of a large surface area. Before discharge initiation, the sheets are baked up to 700 ∼ 1000degC to remove the previously trapped hydrogen atoms. After being cooled down to below ∼ 200degC, the unsaturated carbon sheets trap high energy charge exchange hydrogen atoms effectively during a discharge and overall pumping efficiency can be as high as ∼ 50 %. (author)

College Experience and Volunteering. Fact Sheet

Science.gov (United States)

Marcelo, Karlo Barrios

2007-01-01

College experience and volunteering are positively correlated. Measurable differences in civic activity exist between young people who attend college and young people who do not. This fact sheet explores volunteering as civic engagement among youth with college experience, ages 19-25, which was down for the second year in a row in 2006. The…

FDTD modeling of thin impedance sheets

Science.gov (United States)

Luebbers, Raymond J.; Kunz, Karl S.

1991-01-01

Thin sheets of resistive or dielectric material are commonly encountered in radar cross section calculations. Analysis of such sheets is simplified by using sheet impedances. In this paper it is shown that sheet impedances can be modeled easily and accurately using Finite Difference Time Domain (FDTD) methods.

Structural, electronic structure and antibacterial properties of graphene-oxide nano-sheets

Science.gov (United States)

Sharma, Aditya; Varshney, Mayora; Nanda, Sitansu Sekhar; Shin, Hyun Joon; Kim, Namdong; Yi, Dong Kee; Chae, Keun-Hwa; Ok Won, Sung

2018-04-01

Correlation between the structural/electronic structure properties and bio-activity of graphene-based materials need to be thoroughly evaluated before their commercial implementation in the health and environment precincts. To better investigate the local hybridization of sp2/sp3 orbitals of the functional groups of graphene-oxide (GO) and their execution in the antimicrobial mechanism, we exemplify the antibacterial activity of GO sheets towards the Escherichia coli bacteria (E. coli) by applying the field-emission scanning electron microscopy (FESEM), near edge X-ray absorption fine structure (NEXAFS) and scanning transmission X-ray microscope (STXM) techniques. C K-edge and O K-edge NEXAFS spectra have revealed lesser sp2 carbon atoms in the aromatic ring and attachment of functional oxygen groups at GO sheets. Entrapment of E. coli bacteria by GO sheets is evidenced by FESEM investigations and has also been corroborated by nano-scale imaging of bacteria using the STXM. Spectroscopy evidence of functional oxygen moieties with GO sheets and physiochemical entrapment of E. coli bacteria have assisted us to elaborate the mechanism of cellular oxidative stress-induced disruption of bacterial membrane.

Electrochemically cathodic exfoliation of graphene sheets in room temperature ionic liquids N-butyl, methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and their electrochemical properties

International Nuclear Information System (INIS)

Yang, Yingchang; Lu, Fang; Zhou, Zhou; Song, Weixin; Chen, Qiyuan; Ji, Xiaobo

2013-01-01

Graphical abstract: Electrochemically cathodic exfoliation of graphite into few-layer graphene sheets in room temperature ionic liquids (RTILs) N-butyl, methylpyrrolidinium bis(trifluoromethylsulfonyl)-imide (BMPTF 2 N). -- Highlights: • Few-layer graphene sheets were prepared through electrochemically cathodic exfoliation in room temperature ionic liquids. • The mechanism of cathodic exfoliation in ionic liquids was proposed. • The derived activated graphene sheets show enhanced electrochemical properties. -- Abstract: Electrochemically cathodic exfoliation in room temperature ionic liquids N-butyl, methylpyrrolidinium bis(trifluoromethylsulfonyl)-imide (BMPTF 2 N) has been developed for few-layer graphene sheets, demonstrating low levels of oxygen (2.7 at% of O) with a nearly perfect structure (I D /I G 2 N involves the intercalation of ionic liquids cation [BMP] + under highly negatively charge followed by graphite expansion. Porous activated graphene sheets were also obtained by activation of graphene sheets in KOH. Transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy were used to characterize these graphene materials. The electrochemical performances of the graphene sheets and porous activated graphene sheets for lithium-ion battery anode materials were evaluated using cyclic voltammetry, galvanostatic charge–discharge cycling, and electrochemical impedance spectroscopy

The decisional balance sheet to promote healthy behavior among ethnically diverse older adults.

Science.gov (United States)

Geller, Karly S; Mendoza, Ilora D; Timbobolan, Jasah; Montjoy, Holly L; Nigg, Claudio R

2012-01-01

The rising health care costs and increasing older adult population in the United States make preventive medicine for this age group especially crucial. Regular physical activity and fruit and vegetable consumption may prevent or delay the onset of many chronic conditions that are common among older adults. The decisional balance sheet is a promotional tool targeting the perceived pros and cons of behavior adoption. The current study tested the efficiency and effectiveness of a single-day decisional balance sheet program, targeting increased physical activity and fruit and vegetable intake among older adults. Participating adults (N = 21, age = 72.2) who represented a diverse population in Hawaii (Japanese = 5, Filipino = 4, Caucasian = 4, Native American = 1, Native Hawaiian = 1, Hispanic = 1, and Others = 5) were recruited from housing communities and randomized to a decisional balance sheet program adapted for physical activity or fruit and vegetable consumption. Physical activity was assessed using the International Physical Activity Questionnaire (IPAQ) short form, and daily fruit and vegetable intake with the National Health and Nutrition Examination Survey single item instrument. Baseline and follow-up data were collected. Both programs were implemented efficiently, and participants in both groups improved their daily physical activity. The decisional balance sheet for fruit and vegetable consumption appeared less effective. Specific suggestions for similar programs are reported. © 2011 Wiley Periodicals, Inc.

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

National Research Council Canada - National Science Library

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

1996-01-01

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

Plasma dynamics in current sheets

International Nuclear Information System (INIS)

Bogdanov, S.Yu.; Drejden, G.V.; Kirij, N.P.; AN SSSR, Leningrad

1992-01-01

Plasma dynamics in successive stages of current sheet evolution is investigated on the base of analysis of time-spatial variations of electron density and electrodynamic force fields. Current sheet formation is realized in a two-dimensional magnetic field with zero line under the action of relatively small initial disturbances (linear regimes). It is established that in the limits of the formed sheet is concentrated dense (N e ∼= 10 16 cm -3 ) (T i ≥ 100 eV, bar-Z i ≥ 2) hot pressure of which is balanced by the magnetic action of electrodynamic forces is carried out both plasma compression in the sheet limits and the acceleration along the sheet surface from a middle to narrow side edges

Imaging a seizure model in zebrafish with structured illumination light sheet microscopy

Science.gov (United States)

Liu, Yang; Dale, Savannah; Ball, Rebecca; VanLeuven, Ariel J.; Baraban, Scott; Sornborger, Andrew; Lauderdale, James D.; Kner, Peter

2018-02-01

Zebrafish are a promising vertebrate model for elucidating how neural circuits generate behavior under normal and pathological conditions. The Baraban group first demonstrated that zebrafish larvae are valuable for investigating seizure events and can be used as a model for epilepsy in humans. Because of their small size and transparency, zebrafish embryos are ideal for imaging seizure activity using calcium indicators. Light-sheet microscopy is well suited to capturing neural activity in zebrafish because it is capable of optical sectioning, high frame rates, and low excitation intensities. We describe work in our lab to use light-sheet microscopy for high-speed long-time imaging of neural activity in wildtype and mutant zebrafish to better understand the connectivity and activity of inhibitory neural networks when GABAergic signaling is altered in vivo. We show that, with light-sheet microscopy, neural activity can be recorded at 23 frames per second in twocolors for over 10 minutes allowing us to capture rare seizure events in mutants. We have further implemented structured illumination to increase resolution and contrast in the vertical and axial directions during high-speed imaging at an effective frame rate of over 7 frames per second.

A feedback model of figure-ground assignment.

Science.gov (United States)

Domijan, Drazen; Setić, Mia

2008-05-30

A computational model is proposed in order to explain how bottom-up and top-down signals are combined into a unified perception of figure and background. The model is based on the interaction between the ventral and the dorsal stream. The dorsal stream computes saliency based on boundary signals provided by the simple and the complex cortical cells. Output from the dorsal stream is projected to the surface network which serves as a blackboard on which the surface representation is formed. The surface network is a recurrent network which segregates different surfaces by assigning different firing rates to them. The figure is labeled by the maximal firing rate. Computer simulations showed that the model correctly assigns figural status to the surface with a smaller size, a greater contrast, convexity, surroundedness, horizontal-vertical orientation and a higher spatial frequency content. The simple gradient of activity in the dorsal stream enables the simulation of the new principles of the lower region and the top-bottom polarity. The model also explains how the exogenous attention and the endogenous attention may reverse the figural assignment. Due to the local excitation in the surface network, neural activity at the cued region will spread over the whole surface representation. Therefore, the model implements the object-based attentional selection.

Global ice sheet modeling

International Nuclear Information System (INIS)

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

1994-05-01

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

Sheet production apparatus for removing a crystalline sheet from the surface of a melt using gas jets located above and below the crystalline sheet

Energy Technology Data Exchange (ETDEWEB)

Kellerman, Peter L.; Thronson, Gregory D.

2017-06-14

In one embodiment, a sheet production apparatus comprises a vessel configured to hold a melt of a material. A cooling plate is disposed proximate the melt and is configured to form a sheet of the material on the melt. A first gas jet is configured to direct a gas toward an edge of the vessel. A sheet of a material is translated horizontally on a surface of the melt and the sheet is removed from the melt. The first gas jet may be directed at the meniscus and may stabilize this meniscus or increase local pressure within the meniscus.

Further exploration of the conformational space of α-synuclein fibrils: solid-state NMR assignment of a high-pH polymorph.

Science.gov (United States)

Verasdonck, Joeri; Bousset, Luc; Gath, Julia; Melki, Ronald; Böckmann, Anja; Meier, Beat H

2016-04-01

Polymorphism is a common and important phenomenon for protein fibrils which has been linked to the appearance of strains in prion and other neurodegenerative diseases. Parkinson disease is a frequently occurring neurodegenerative pathology, tightly associated with the formation of Lewy bodies. These deposits mainly consist of α-synuclein in fibrillar, β-sheet-rich form. α-synuclein is known to form numerous different polymorphs, which show distinct structural features. Here, we describe the chemical shift assignments, and derive the secondary structure, of a polymorph that was fibrillized at higher-than-physiological pH conditions. The fibrillar core contains residues 40-95, with both the C- and N-terminus not showing any ordered, rigid parts. The chemical shifts are similar to those recorded previously for an assigned polymorph that was fibrillized at neutral pH.

Someday I May Want to Know about...Leisure and Recreational Activities for Children and Adults with Mental Retardation. A MCARC Information Sheet.

Science.gov (United States)

Montgomery County Association for Retarded Citizens, Rockville, MD.

The fact sheet considers the importance of recreation and leisure time activities for people with mental retardation. A case is made for mainstreamed services, and suggestions are offered for families seeking to procure successful mainstreamed experiences in community recreational programs. Among suggestions are adapting family games to the…

Aligned carbon nanotube-silicon sheets: a novel nano-architecture for flexible lithium ion battery electrodes.

Science.gov (United States)

Fu, Kun; Yildiz, Ozkan; Bhanushali, Hardik; Wang, Yongxin; Stano, Kelly; Xue, Leigang; Zhang, Xiangwu; Bradford, Philip D

2013-09-25

Aligned carbon nanotube sheets provide an engineered scaffold for the deposition of a silicon active material for lithium ion battery anodes. The sheets are low-density, allowing uniform deposition of silicon thin films while the alignment allows unconstrained volumetric expansion of the silicon, facilitating stable cycling performance. The flat sheet morphology is desirable for battery construction. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Image Classification of Ribbed Smoked Sheet using Learning Vector Quantization

Science.gov (United States)

Rahmat, R. F.; Pulungan, A. F.; Faza, S.; Budiarto, R.

2017-01-01

Natural rubber is an important export commodity in Indonesia, which can be a major contributor to national economic development. One type of rubber used as rubber material exports is Ribbed Smoked Sheet (RSS). The quantity of RSS exports depends on the quality of RSS. RSS rubber quality has been assigned in SNI 06-001-1987 and the International Standards of Quality and Packing for Natural Rubber Grades (The Green Book). The determination of RSS quality is also known as the sorting process. In the rubber factones, the sorting process is still done manually by looking and detecting at the levels of air bubbles on the surface of the rubber sheet by naked eyes so that the result is subjective and not so good. Therefore, a method is required to classify RSS rubber automatically and precisely. We propose some image processing techniques for the pre-processing, zoning method for feature extraction and Learning Vector Quantization (LVQ) method for classifying RSS rubber into two grades, namely RSS1 and RSS3. We used 120 RSS images as training dataset and 60 RSS images as testing dataset. The result shows that our proposed method can give 89% of accuracy and the best perform epoch is in the fifteenth epoch.

1H NMR studies of plastocyanin from Scenedesmus obliquus: Complete sequence-specific assignment, secondary structure analysis, and global fold

International Nuclear Information System (INIS)

Moore, J.M.; Chazin, W.J.; Wright, P.E.; Powls, R.

1988-01-01

Two-dimensional 1 H NMR methods have been used to make sequence-specific resonance assignments for the 97 amino acid residues of the plastocyanin from the green alga Scenedesmus obliquus. Assignments were obtained for all backbone protons and the majority of the side-chain protons. Spin system identification relied heavily on the observation of relayed connectivities to the backbone amide proton. Sequence-specific assignments were made by using the sequential assignment procedure. During this process, an extra valine residue was identified that had not been detected in the original amino acid sequence. Elements of regular secondary structure were identified from characteristic NOE connectivities between backbone protons, coupling constant values, and the observation of slowly exchanging amide protons. The protein in solution contains eight β-strands, one short segment of helix, five reverse turns, and five loops. The β-strands may be arranged into two βsheets on the basis of extensive cross-strand NOE connectivities. The chain-folding topology determined from the NMR experiments is that of a Greek key β-barrel and is similar to that observed for French bean plastocyanin in solution and poplar plastocyanin in the crystalline state. While the overall structures are similar, several differences in local structure between the S. obliquus and higher plant plastocyanins have been identified

Web-based Tools for Educators: Outreach Activities of the Polar Radar for Ice Sheet Measurements (PRISM) Project

Science.gov (United States)

Braaten, D. A.; Holvoet, J. F.; Gogineni, S.

2003-12-01

The Radar Systems and Remote Sensing Laboratory at the University of Kansas (KU) has implemented extensive outreach activities focusing on Polar Regions as part of the Polar Radar for Ice Sheet Measurements (PRISM) project. The PRISM project is developing advanced intelligent remote sensing technology that involves radar systems, an autonomous rover, and communications systems to measure detailed ice sheet characteristics, and to determine bed conditions (frozen or wet) below active ice sheets in both Greenland and Antarctica. These measurements will provide a better understanding of the response of polar ice sheets to global climate change and the resulting impact the ice sheets will have on sea level rise. Many of the research and technological development aspects of the PRISM project, such as robotics, radar systems, climate change and exploration of harsh environments, can kindle an excitement and interest in students about science and technology. These topics form the core of our K-12 education and training outreach initiatives, which are designed to capture the imagination of young students, and prompt them to consider an educational path that will lead them to scientific or engineering careers. The K-12 PRISM outreach initiatives are being developed and implemented in a collaboration with the Advanced Learning Technology Program (ALTec) of the High Plains Regional Technology in Education Consortium (HPR*TEC). ALTec is associated with the KU School of Education, and is a well-established educational research center that develops and hosts web tools to enable teachers nationwide to network, collaborate, and share resources with other teachers. An example of an innovative and successful web interface developed by ALTec is called TrackStar. Teachers can use TrackStar over the Web to develop interactive, resource-based lessons (called tracks) on-line for their students. Once developed, tracks are added to the TrackStar database and can be accessed and modified

On the energy release rate in a turbulent current sheet on the Sun

International Nuclear Information System (INIS)

Bardakov, V.M.

1986-01-01

It is shown that turbulent current sheets on the Sun, realizing in the form of the Parker - Sweet flow, are in quasilinear regime of turbulence (or in the regime of instability threshold). The energy release rate in such sheets does not exceed 10 26 erg/s for typical plasma parameters in active regions

Orientation determination of interfacial beta-sheet structures in situ.

Science.gov (United States)

Nguyen, Khoi Tan; King, John Thomas; Chen, Zhan

2010-07-01

Structural information such as orientations of interfacial proteins and peptides is important for understanding properties and functions of such biological molecules, which play crucial roles in biological applications and processes such as antimicrobial selectivity, membrane protein activity, biocompatibility, and biosensing performance. The alpha-helical and beta-sheet structures are the most widely encountered secondary structures in peptides and proteins. In this paper, for the first time, a method to quantify the orientation of the interfacial beta-sheet structure using a combined attenuated total reflectance Fourier transformation infrared spectroscopic (ATR-FTIR) and sum frequency generation (SFG) vibrational spectroscopic study was developed. As an illustration of the methodology, the orientation of tachyplesin I, a 17 amino acid peptide with an antiparallel beta-sheet, adsorbed to polymer surfaces as well as associated with a lipid bilayer was determined using the regular and chiral SFG spectra, together with polarized ATR-FTIR amide I signals. Both the tilt angle (theta) and the twist angle (psi) of the beta-sheet at interfaces are determined. The developed method in this paper can be used to obtain in situ structural information of beta-sheet components in complex molecules. The combination of this method and the existing methodology that is currently used to investigate alpha-helical structures will greatly broaden the application of optical spectroscopy in physical chemistry, biochemistry, biophysics, and structural biology.

UOP LDR 300 All Assignments New

OpenAIRE

ADMIN

2018-01-01

UOP LDR 300 All Assignments New Check this A+ tutorial guideline at http://www.ldr300assignment.com/ldr-300-uop/ldr-300-all-assignments-latest For more classes visit http://www.ldr300assignment.com LDR 300 Week 1 Assignment Leadership Assessment (2 Papers) LDR 300 Week 2 Assignment Leadership Theories Matrix (2 Set) LDR 300 Week 2 Assignment Formulating Leadership Part I (2 Papers) LDR 300 Week 3 Assignment Interaction and Influence Amo...

Vitamin and Mineral Supplement Fact Sheets

Science.gov (United States)

... website Submit Search NIH Office of Dietary Supplements Vitamin and Mineral Supplement Fact Sheets Search the list ... Supplements: Background Information Botanical Dietary Supplements: Background Information Vitamin and Mineral Fact Sheets Botanical Supplement Fact Sheets ...

Dynamics of Radially Expanding Liquid Sheets

Science.gov (United States)

Majumdar, Nayanika; Tirumkudulu, Mahesh S.

2018-04-01

The process of atomization often involves ejecting thin liquid sheets at high speeds from a nozzle that causes the sheet to flap violently and break up into fine droplets. The flapping of the liquid sheet has long been attributed to the sheet's interaction with the surrounding gas phase. Here, we present experimental evidence to the contrary and show that the flapping is caused by the thinning of the liquid sheet as it spreads out from the nozzle exit. The measured growth rates of the waves agree remarkably well with the predictions of a recent theory that accounts for the sheet's thinning but ignores aerodynamic interactions. We anticipate these results to not only lead to more accurate predictions of the final drop-size distribution but also enable more efficient designs of atomizers.

Buckling and stretching of thin viscous sheets

Science.gov (United States)

O'Kiely, Doireann; Breward, Chris; Griffiths, Ian; Howell, Peter; Lange, Ulrich

2016-11-01

Thin glass sheets are used in smartphone, battery and semiconductor technology, and may be manufactured by producing a relatively thick glass slab and subsequently redrawing it to a required thickness. The resulting sheets commonly possess undesired centerline ripples and thick edges. We present a mathematical model in which a viscous sheet undergoes redraw in the direction of gravity, and show that, in a sufficiently strong gravitational field, buckling is driven by compression in a region near the bottom of the sheet, and limited by viscous resistance to stretching of the sheet. We use asymptotic analysis in the thin-sheet, low-Reynolds-number limit to determine the centerline profile and growth rate of such a viscous sheet.

Fair Package Assignment

Science.gov (United States)

Lahaie, Sébastien; Parkes, David C.

We consider the problem of fair allocation in the package assignment model, where a set of indivisible items, held by single seller, must be efficiently allocated to agents with quasi-linear utilities. A fair assignment is one that is efficient and envy-free. We consider a model where bidders have superadditive valuations, meaning that items are pure complements. Our central result is that core outcomes are fair and even coalition-fair over this domain, while fair distributions may not even exist for general valuations. Of relevance to auction design, we also establish that the core is equivalent to the set of anonymous-price competitive equilibria, and that superadditive valuations are a maximal domain that guarantees the existence of anonymous-price competitive equilibrium. Our results are analogs of core equivalence results for linear prices in the standard assignment model, and for nonlinear, non-anonymous prices in the package assignment model with general valuations.

Reflective practice: assessment of assignments in English for Specific Purposes

Directory of Open Access Journals (Sweden)

Galina Kavaliauskiené

2007-10-01

Full Text Available The construct alternative assessment has been widely used in higher education. It is often defined as any type of assessment of learners who provide a response to an assignment. The key features of alternative assessment are active participation of learners in self-evaluation of their performance, and the development of reflective thinking through reflective thinking (Schön, 1983. The success of alternative assessment in language teaching is predetermined by student’s performance and demonstrates learner’s language proficiency in contemporary communicative classrooms. This paper aims at researching the influence of students’ evaluations of various assignments for their linguistic development in English for Specific Purposes (ESP. The study uses learners’ assessment of different assignments and learners’ in-course and post-course written reflections on benefits to language mastery. Learners’ assignments included were contributions to portfolios (dossiers, such as essays and summaries, oral presentations, short impromptu talks, creative tasks, tests, and self-assessment notes (reflections on activities in learning ESP. Findings were obtained for two streams of the project participants. Results showed that self-assessment was beneficial for learners’ linguistic development. The context of learners’ reflections reveals that the attitudes to various assignments are affected by success or failure in students’ performance. Reflective practice might help teachers develop ways of dealing with previously identified difficulties and improve the quality of teaching.

Design and results of the ice sheet model initialisation initMIP-Greenland: an ISMIP6 intercomparison

Directory of Open Access Journals (Sweden)

H. Goelzer

2018-04-01

Full Text Available Earlier large-scale Greenland ice sheet sea-level projections (e.g. those run during the ice2sea and SeaRISE initiatives have shown that ice sheet initial conditions have a large effect on the projections and give rise to important uncertainties. The goal of this initMIP-Greenland intercomparison exercise is to compare, evaluate, and improve the initialisation techniques used in the ice sheet modelling community and to estimate the associated uncertainties in modelled mass changes. initMIP-Greenland is the first in a series of ice sheet model intercomparison activities within ISMIP6 (the Ice Sheet Model Intercomparison Project for CMIP6, which is the primary activity within the Coupled Model Intercomparison Project Phase 6 (CMIP6 focusing on the ice sheets. Two experiments for the large-scale Greenland ice sheet have been designed to allow intercomparison between participating models of (1 the initial present-day state of the ice sheet and (2 the response in two idealised forward experiments. The forward experiments serve to evaluate the initialisation in terms of model drift (forward run without additional forcing and in response to a large perturbation (prescribed surface mass balance anomaly; they should not be interpreted as sea-level projections. We present and discuss results that highlight the diversity of data sets, boundary conditions, and initialisation techniques used in the community to generate initial states of the Greenland ice sheet. We find good agreement across the ensemble for the dynamic response to surface mass balance changes in areas where the simulated ice sheets overlap but differences arising from the initial size of the ice sheet. The model drift in the control experiment is reduced for models that participated in earlier intercomparison exercises.

Ohm's law for a current sheet

Science.gov (United States)

Lyons, L. R.; Speiser, T. W.

1985-01-01

The paper derives an Ohm's law for single-particle motion in a current sheet, where the magnetic field reverses in direction across the sheet. The result is considerably different from the resistive Ohm's law often used in MHD studies of the geomagnetic tail. Single-particle analysis is extended to obtain a self-consistency relation for a current sheet which agrees with previous results. The results are applicable to the concept of reconnection in that the electric field parallel to the current is obtained for a one-dimensional current sheet with constant normal magnetic field. Dissipated energy goes directly into accelerating particles within the current sheet.

Catalog of CERCLA applicable or relevant and appropriate requirements (ARARs) - fact sheets

Energy Technology Data Exchange (ETDEWEB)

1990-07-01

Section 121(d) of the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA), requires attainment of federal and state applicable or relevant and appropriate requirements (ARARs). Subpart E, Section 300.400(g) {open_quotes}Identification of applicable or relevant and appropriate requirements{close_quotes} of the National Oil and Hazardous Substances Pollution Contingency Plan (NCP)(55 FR 8666, March 8, 1990) describes the process for attaining ARARs. The purpose of this catalog is to provide DOE Program Offices and Field Organizations with all of the {open_quotes}Quick Reference Fact Sheets{close_quotes} on attaining ARARS. These fact sheets provide overviews of ARARs for CERCLA cleanup actions pertinent to DOE environmental restoration activities. All of the fact sheets in this catalog were prepared by the Environmental Protection Agency`s Office of Solid Waste and Emergency Response. Fact sheets 1-7 discuss land disposal restrictions (LDRs) and their applicability. LDRs may pertain to a number of CERCLA response actions at DOE facilities. Fact Sheets 8-13 are based on the CERCLA Compliance with Other Laws Manual: Parts I and II and provide an overview of many other CERCLA ARARs. Overview of ARARs-Focus on ARAR Waivers (fact sheet 11), provides a good introduction to ARARS. The last two fact sheets, 14 and 15, are periodic reports that describe additional fact sheets and clarify issues.

Adjustable focus laser sheet module for generating constant maximum width sheets for use in optical flow diagnostics

International Nuclear Information System (INIS)

Hult, J; Mayer, S

2011-01-01

A general design of a laser light sheet module with adjustable focus is presented, where the maximum sheet width is preserved over a fixed region. In contrast, conventional focusing designs are associated with a variation in maximum sheet width with focal position. A four lens design is proposed here, where the first three lenses are employed for focusing, and the last for sheet expansion. A maximum sheet width of 1100 µm was maintained over a 50 mm long distance, for focal distances ranging from 75 to 500 mm, when a 532 nm laser beam with a beam quality factor M 2 = 29 was used for illumination

Comprehensive Small Engine Repair.

Science.gov (United States)

Hires, Bill; And Others

This curriculum guide contains the basic information needed to repair all two- and four-stroke cycle engines. The curriculum covers four areas, each consisting of one or more units of instruction that include performance objectives, suggested activities for teacher and students, information sheets, assignment sheets, job sheets, visual aids,…

Plagiarism-Proofing Assignments

Science.gov (United States)

Johnson, Doug

2004-01-01

Mr. Johnson has discovered that the higher the level of student engagement and creativity, the lower the probability of plagiarism. For teachers who would like to see such desirable results, he describes the characteristics of assignments that are most likely to produce them. Two scenarios of types of assignments that avoid plagiarism are…

Nano-scaled hydroxyapatite/silk fibroin sheets support osteogenic differentiation of rat bone marrow mesenchymal cells

International Nuclear Information System (INIS)

Tanaka, Toshimitsu; Hirose, Motohiro; Kotobuki, Noriko; Ohgushi, Hajime; Furuzono, Tsutomu; Sato, Junichi

2007-01-01

A novel biomaterial that was composed of nano-scaled sintered hydroxyapatite (HAp) and silk fibroin (SF) was fabricated. We cultured rat marrow mesenchymal cells (MMCs) on this biomaterial (nano-HAp/SF sheet), on bare SF sheets, and on tissue culture polystyrene (TCPS) dishes as controls, then evaluated cell adhesion, proliferation, and differentiation of the MMCs. After 1 h of culture, a large number of viable cells were observed on the nano-HAp/SF sheets in comparison to the controls. In addition, after 3 h of culture, the morphology of the cells on the nano-HAp/SF sheets was quite different from that on the SF sheets. MMCs extrude their cytoplasmic processes to nano-HAp particles and are well attached to the sheets. After 14 days of culture, under osteogenic conditions, the alkaline phosphatase (ALP) activity and bone-specific osteocalcin secretion of the cells on nano-HAp/SF sheets were higher than were those on the controls. These results indicated that the surface of the nano-HAp/SF sheets is covered with appropriate HAp crystal for MMC adhesion/proliferation and that the sheets effectively support the osteogenic differentiation of MMCs. Therefore, the nano-HAp/SF sheet is an effective biomaterial that is applicable in bone reconstruction surgery

Improving Climate Literacy Using The Ice Sheet System Model (ISSM): A Prototype Virtual Ice Sheet Laboratory For Use In K-12 Classrooms

Science.gov (United States)

Halkides, D. J.; Larour, E. Y.; Perez, G.; Petrie, K.; Nguyen, L.

2013-12-01

Statistics indicate that most Americans learn what they will know about science within the confines of our public K-12 education system and the media. Next Generation Science Standards (NGSS) aim to remedy science illiteracy and provide guidelines to exceed the Common Core State Standards that most U.S. state governments have adopted, by integrating disciplinary cores with crosscutting ideas and real life practices. In this vein, we present a prototype ';Virtual Ice Sheet Laboratory' (I-Lab), geared to K-12 students, educators and interested members of the general public. I-Lab will allow users to perform experiments using a state-of-the-art dynamical ice sheet model and provide detailed downloadable lesson plans, which incorporate this model and are consistent with NGSS Physical Science criteria for different grade bands (K-2, 3-5, 6-8, and 9-12). The ultimate goal of this website is to improve public climate science literacy, especially in regards to the crucial role of the polar ice sheets in Earth's climate and sea level. The model used will be the Ice Sheet System Model (ISSM), an ice flow model developed at NASA's Jet Propulsion Laboratory and UC Irvine, that simulates the near-term evolution of polar ice sheets (Greenland and Antarctica) and includes high spatial resolution capabilities and data assimilation to produce realistic simulations of ice sheet dynamics at the continental scale. Open sourced since 2011, ISSM is used in cutting edge cryosphere research around the globe. Thru I-Lab, students will be able to access ISSM using a simple, online graphical interface that can be launched from a web browser on a computer, tablet or smart phone. The interface will allow users to select different climate conditions and watch how the polar ice sheets evolve in time under those conditions. Lesson contents will include links to background material and activities that teach observation recording, concept articulation, hypothesis formulation and testing, and

Main-chain-directed strategy for the assignment of 1H NMR spectra of proteins

International Nuclear Information System (INIS)

Englander, S.W.; Wand, A.J.

1987-01-01

A strategy for assigning the resonances in two-dimensional (2D) NMR spectra of proteins is described. The method emphasizes the analysis of through-space relationships between protons by use of the two-dimensional nuclear Overhauser effect (NOE) experiment. NOE patterns used in the algorithm were derived from a statistical analysis of the combinations of short proton-proton distances observed in the high-resolution crystal structures of 21 proteins. One starts with a search for authentic main-chain NH-C/sub α/H-C/sub β/H J-coupled units, which can be found with high reliability. The many main-chain units of a protein are then placed in their proper juxtaposition by recognition of predefined NOE connectivity patterns. To discover these connectivities, the 2D NOE spectrum is examined, in a prescribed order, for the distinct NOE patterns characteristic of helices, sheets, turns, and extended chain. Finally, the recognition of a few amino acid side-chain types places the discovered secondary structure elements within the polypeptide sequences. Unlike the sequential assignment approach, the main-chain-directed strategy does not rely on the difficult task of recognizing many side-chain spin systems in J-correlated spectra, the assignment process is not in general sequential with the polypeptide chain, and the prescribed connectivity patterns are cyclic rather than linear. The latter characteristic avoids ambiguous branch points in the analysis and imposed an internally confirmatory property on each forward step

Interactive Ice Sheet Flowline Model for High School and College Students

Science.gov (United States)

Stearns, L. A.; Rezvanbehbahani, S.; Shankar, S.

2017-12-01

Teaching about climate and climate change is conceptually challenging. While teaching tools and lesson plans are rapidly evolving to help teachers and students improve their understanding of climate processes, there are very few tools targeting ice sheet and glacier dynamics. We have built an interactive ice sheet model that allows students to explore how Antarctic glaciers respond to different climate perturbations. Interactive models offer advantages that are hard to obtain in traditional classroom settings; users can systematically investigate hypothetical situations, explore the effects of modifying systems, and repeatedly observe how systems interrelate. As a result, this project provides a much-needed bridge between the data and models used by the scientific community and students in high school and college. We target our instructional and assessment activities to three high school and college students with the overall aim of increasing understanding of ice sheet dynamics and the different ways that ice sheets are impacted by climate change, while also improving their fundamental math skills.

Calibration of a joint time assignment and mode choice model system

OpenAIRE

Greeven, Paulina; Jara-Diaz, Sergio R.; Munizaga, Marcela A.; Axhausen, Kay W.

2005-01-01

In this paper we report the results of applying a new microeconomic framework to model time assignment to activities, goods consumption and mode choice jointly (Jara-Díaz and Guevara, 2003; Jara-Díaz and Guerra, 2003) that identifies the links between these decisions and permits the calculation of all the components of the subjective value of time defined in the literature: the value of time as a resource, value of assigning time to a specific activity and the value of saving time in a specif...

17 CFR 210.6-04 - Balance sheets.

Science.gov (United States)

2010-04-01

... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Balance sheets. 210.6-04... sheets. This rule is applicable to balance sheets filed by registered investment companies except for... of this part. Balance sheets filed under this rule shall comply with the following provisions: Assets...

Ice sheet in peril

DEFF Research Database (Denmark)

Hvidberg, Christine Schøtt

2016-01-01

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

The transposition of the balance sheet to financial and functional balance sheet. Research and development

Directory of Open Access Journals (Sweden)

Liana GĂDĂU

2015-09-01

Full Text Available As the title suggests, through this paper we want to highlight the necessity of treating again the content and the form of the balance sheet in order to adapt it to a more efficient analysis, this way surpassing the informational valences of the classic balance sheet. The functional and the financial balance sheet will be taken into account. These models of balance sheet permit the complex analyses regarding the solvability or the bankruptcy risk of an enterprise to take place, and also other analyses, like the analysis of the structure and the financial/ functional equilibrium, the analysis of the company on operating cycles and their role in the functioning of the company. Through the particularities offered by each of these two models of balance sheet, we want to present the advantages of a superior informing. This content of this material is based on a vast investigation of the specialized literature.

Effect of heat- and steam-generating sheet on daily activities of living in patients with osteoarthritis of the knee: randomized prospective study.

Science.gov (United States)

Seto, Hiroaki; Ikeda, Hiroshi; Hisaoka, Hidehiko; Kurosawa, Hisashi

2008-05-01

Thermotherapy is widely known to be effective for osteoarthritis of the knee (knee OA), but most treatment methods make use of dry heat. We developed a sheet that generates heat and steam simultaneously. In this prospective randomized study, we evaluated the effectiveness of this sheet. Of 41 female patients with knee OA randomized to use the heat/steam-generating sheet or the dry heat-generating sheet, 37 patients (20 using the heat/steam-generating sheet and 17 using the dry heat-generating sheet) who used the sheets continuously for 4 weeks were studied. Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Japan Orthopaedic Association (JOA) scores, which were applied at baseline and after 2 and 4 weeks of use. Significant improvement of the total WOMAC score was observed at 2 and 4 weeks (compared to baseline) in the heat/steam-generating sheet group, but no significant change was observed in the dry heat-generating sheet group. Among the JOA scores, the gait ability score was also improved significantly only in the heat/steam-generating sheet group. The effects were still seen 6 weeks after completion of treatment. The present study provided evidence that the heat/steam-generating sheet that we developed is effective for alleviating pain and is especially superior in regard to improving stiffness and gait impairment in patients with knee OA. Furthermore, the effect persists for at least 6 weeks after application.

Effect of Temperature and Sheet Temper on Isothermal Solidification Kinetics in Clad Aluminum Brazing Sheet

Science.gov (United States)

Benoit, Michael J.; Whitney, Mark A.; Wells, Mary A.; Winkler, Sooky

2016-09-01

Isothermal solidification (IS) is a phenomenon observed in clad aluminum brazing sheets, wherein the amount of liquid clad metal is reduced by penetration of the liquid clad into the core. The objective of the current investigation is to quantify the rate of IS through the use of a previously derived parameter, the Interface Rate Constant (IRC). The effect of peak temperature and initial sheet temper on IS kinetics were investigated. The results demonstrated that IS is due to the diffusion of silicon (Si) from the liquid clad layer into the solid core. Reduced amounts of liquid clad at long liquid duration times, a roughened sheet surface, and differences in resolidified clad layer morphology between sheet tempers were observed. Increased IS kinetics were predicted at higher temperatures by an IRC model as well as by experimentally determined IRC values; however, the magnitudes of these values are not in good agreement due to deficiencies in the model when applied to alloys. IS kinetics were found to be higher for sheets in the fully annealed condition when compared with work-hardened sheets, due to the influence of core grain boundaries providing high diffusivity pathways for Si diffusion, resulting in more rapid liquid clad penetration.

Assessment of Random Assignment in Training and Test Sets using Generalized Cluster Analysis Technique

Directory of Open Access Journals (Sweden)

Sorana D. BOLBOACĂ

2011-06-01

Full Text Available Aim: The properness of random assignment of compounds in training and validation sets was assessed using the generalized cluster technique. Material and Method: A quantitative Structure-Activity Relationship model using Molecular Descriptors Family on Vertices was evaluated in terms of assignment of carboquinone derivatives in training and test sets during the leave-many-out analysis. Assignment of compounds was investigated using five variables: observed anticancer activity and four structure descriptors. Generalized cluster analysis with K-means algorithm was applied in order to investigate if the assignment of compounds was or not proper. The Euclidian distance and maximization of the initial distance using a cross-validation with a v-fold of 10 was applied. Results: All five variables included in analysis proved to have statistically significant contribution in identification of clusters. Three clusters were identified, each of them containing both carboquinone derivatives belonging to training as well as to test sets. The observed activity of carboquinone derivatives proved to be normal distributed on every. The presence of training and test sets in all clusters identified using generalized cluster analysis with K-means algorithm and the distribution of observed activity within clusters sustain a proper assignment of compounds in training and test set. Conclusion: Generalized cluster analysis using the K-means algorithm proved to be a valid method in assessment of random assignment of carboquinone derivatives in training and test sets.

Energy information sheets

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-07-01

The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the public. The Energy Information Sheets was developed to provide general information on various aspects of fuel production, prices, consumption, and capability. Additional information on related subject matter can be found in other Energy Information Administration (EIA) publications as referenced at the end of each sheet.

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...

A comprehensive evaluation of the toxicology of the "Deli" cast sheet process used in experimental cigarettes.

Science.gov (United States)

Coggins, Christopher R E; Merski, Jerome A; Oldham, Michael J

2013-01-01

Manufacture of cigarettes results in tobacco by-products, some of which can be processed and added back to cigarettes. Such additions (known as reconstituted tobacco or reconstituted leaf) have been shown to reduce tar yields. A new process (termed "Deli" cast sheet) is a potential refinement of the reconstitution process. Compare toxicity of smoke from experimental cigarettes made with reconstituted leaf with that from cigarettes made with Deli cast sheet. Analytical chemistry, Salmonella mutagenicity and cytotoxicity assays were used to evaluate the composition biological activity of mainstream smoke from experimental cigarettes made with Deli cast sheet or with reconstituted leaf. The effect of different amounts of guar and propylene glycol in Deli cast sheet was also evaluated. Small increases in the amount of nitrogen oxides were found as a result of inclusion of the Deli cast sheet when compared with reconstituted leaf; no differences in cytotoxicity or mutagenicity were found. The Deli process neither significantly modified chemical composition of smoke nor affected its biological activity, as measured by the mutagenicity and cytotoxicity assays used here.

Predicting Pulsar Scintillation from Refractive Plasma Sheets

Science.gov (United States)

Simard, Dana; Pen, Ue-Li

2018-05-01

The dynamic and secondary spectra of many pulsars show evidence for long-lived, aligned images of the pulsar that are stationary on a thin scattering sheet. One explanation for this phenomenon considers the effects of wave crests along sheets in the ionized interstellar medium, such as those due to Alfvén waves propagating along current sheets. If these sheets are closely aligned to our line-of-sight to the pulsar, high bending angles arise at the wave crests and a selection effect causes alignment of images produced at different crests, similar to grazing reflection off of a lake. Using geometric optics, we develop a simple parameterized model of these corrugated sheets that can be constrained with a single observation and that makes observable predictions for variations in the scintillation of the pulsar over time and frequency. This model reveals qualitative differences between lensing from overdense and underdense corrugated sheets: Only if the sheet is overdense compared to the surrounding interstellar medium can the lensed images be brighter than the line-of-sight image to the pulsar, and the faint lensed images are closer to the pulsar at higher frequencies if the sheet is underdense, but at lower frequencies if the sheet is overdense.

The Utility of Writing Assignments in Undergraduate Bioscience

Science.gov (United States)

Libarkin, Julie; Ording, Gabriel

2012-01-01

We tested the hypothesis that engagement in a few, brief writing assignments in a nonmajors science course can improve student ability to convey critical thought about science. A sample of three papers written by students (n = 30) was coded for presence and accuracy of elements related to scientific writing. Scores for different aspects of scientific writing were significantly correlated, suggesting that students recognized relationships between components of scientific thought. We found that students' ability to write about science topics and state conclusions based on data improved over the course of three writing assignments, while the abilities to state a hypothesis and draw clear connections between human activities and environmental impacts did not improve. Three writing assignments generated significant change in student ability to write scientifically, although our results suggest that three is an insufficient number to generate complete development of scientific writing skills. PMID:22383616

Design and results of the ice sheet model initialisation experiments initMIP-Greenland: an ISMIP6 intercomparison

Science.gov (United States)

Goelzer, Heiko; Nowicki, Sophie; Edwards, Tamsin; Beckley, Matthew; Abe-Ouchi, Ayako; Aschwanden, Andy; Calov, Reinhard; Gagliardini, Olivier; Gillet-Chaulet, Fabien; Golledge, Nicholas R.; Gregory, Jonathan; Greve, Ralf; Humbert, Angelika; Huybrechts, Philippe; Kennedy, Joseph H.; Larour, Eric; Lipscomb, William H.; Le clec'h, Sébastien; Lee, Victoria; Morlighem, Mathieu; Pattyn, Frank; Payne, Antony J.; Rodehacke, Christian; Rückamp, Martin; Saito, Fuyuki; Schlegel, Nicole; Seroussi, Helene; Shepherd, Andrew; Sun, Sainan; van de Wal, Roderik; Ziemen, Florian A.

2018-04-01

Earlier large-scale Greenland ice sheet sea-level projections (e.g. those run during the ice2sea and SeaRISE initiatives) have shown that ice sheet initial conditions have a large effect on the projections and give rise to important uncertainties. The goal of this initMIP-Greenland intercomparison exercise is to compare, evaluate, and improve the initialisation techniques used in the ice sheet modelling community and to estimate the associated uncertainties in modelled mass changes. initMIP-Greenland is the first in a series of ice sheet model intercomparison activities within ISMIP6 (the Ice Sheet Model Intercomparison Project for CMIP6), which is the primary activity within the Coupled Model Intercomparison Project Phase 6 (CMIP6) focusing on the ice sheets. Two experiments for the large-scale Greenland ice sheet have been designed to allow intercomparison between participating models of (1) the initial present-day state of the ice sheet and (2) the response in two idealised forward experiments. The forward experiments serve to evaluate the initialisation in terms of model drift (forward run without additional forcing) and in response to a large perturbation (prescribed surface mass balance anomaly); they should not be interpreted as sea-level projections. We present and discuss results that highlight the diversity of data sets, boundary conditions, and initialisation techniques used in the community to generate initial states of the Greenland ice sheet. We find good agreement across the ensemble for the dynamic response to surface mass balance changes in areas where the simulated ice sheets overlap but differences arising from the initial size of the ice sheet. The model drift in the control experiment is reduced for models that participated in earlier intercomparison exercises.

Energized Oxygen : Speiser Current Sheet Bifurcation

Science.gov (United States)

George, D. E.; Jahn, J. M.

2017-12-01

A single population of energized Oxygen (O+) is shown to produce a cross-tail bifurcated current sheet in 2.5D PIC simulations of the magnetotail without the influence of magnetic reconnection. Treatment of oxygen in simulations of space plasmas, specifically a magnetotail current sheet, has been limited to thermal energies despite observations of and mechanisms which explain energized ions. We performed simulations of a homogeneous oxygen background, that has been energized in a physically appropriate manner, to study the behavior of current sheets and magnetic reconnection, specifically their bifurcation. This work uses a 2.5D explicit Particle-In-a-Cell (PIC) code to investigate the dynamics of energized heavy ions as they stream Dawn-to-Dusk in the magnetotail current sheet. We present a simulation study dealing with the response of a current sheet system to energized oxygen ions. We establish a, well known and studied, 2-species GEM Challenge Harris current sheet as a starting point. This system is known to eventually evolve and produce magnetic reconnection upon thinning of the current sheet. We added a uniform distribution of thermal O+ to the background. This 3-species system is also known to eventually evolve and produce magnetic reconnection. We add one additional variable to the system by providing an initial duskward velocity to energize the O+. We also traced individual particle motion within the PIC simulation. Three main results are shown. First, energized dawn- dusk streaming ions are clearly seen to exhibit sustained Speiser motion. Second, a single population of heavy ions clearly produces a stable bifurcated current sheet. Third, magnetic reconnection is not required to produce the bifurcated current sheet. Finally a bifurcated current sheet is compatible with the Harris current sheet model. This work is the first step in a series of investigations aimed at studying the effects of energized heavy ions on magnetic reconnection. This work differs

Experimental formability analysis of bondal sandwich sheet

Science.gov (United States)

Kami, Abdolvahed; Banabic, Dorel

2018-05-01

Metal/polymer/metal sandwich sheets have recently attracted the interests of industries like automotive industry. These sandwich sheets have superior properties over single-layer metallic sheets including good sound and vibration damping and light weight. However, the formability of these sandwich sheets should be enhanced which requires more research. In this paper, the formability of Bondal sheet (DC06/viscoelastic polymer/DC06 sandwich sheet) was studied through different types of experiments. The mechanical properties of Bondal were determined by uniaxial tensile tests. Hemispherical punch stretching and hydraulic bulge tests were carried out to determine the forming limit diagram (FLD) of Bondal. Furthermore, cylindrical and square cup drawing tests were performed in dry and oil lubricated conditions. These tests were conducted at different blank holding forces (BHFs). An interesting observation about Bondal sheet deep drawing was obtaining of higher drawing depths at dry condition in comparison with oil-lubricated condition.

A Statistical Programme Assignment Model

DEFF Research Database (Denmark)

Rosholm, Michael; Staghøj, Jonas; Svarer, Michael

When treatment effects of active labour market programmes are heterogeneous in an observable way  across the population, the allocation of the unemployed into different programmes becomes a particularly  important issue. In this paper, we present a statistical model designed to improve the present...... duration of unemployment spells may result if a statistical programme assignment model is introduced. We discuss several issues regarding the  plementation of such a system, especially the interplay between the statistical model and  case workers....

Ice sheet hydrology - a review

International Nuclear Information System (INIS)

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

2007-03-01

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

Ice sheet hydrology - a review

Energy Technology Data Exchange (ETDEWEB)

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

2007-03-15

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

Disintegration of liquid sheets

Science.gov (United States)

Mansour, Adel; Chigier, Norman

1990-01-01

The development, stability, and disintegration of liquid sheets issuing from a two-dimensional air-assisted nozzle is studied. Detailed measurements of mean drop size and velocity are made using a phase Doppler particle analyzer. Without air flow the liquid sheet converges toward the axis as a result of surface tension forces. With airflow a quasi-two-dimensional expanding spray is formed. The air flow causes small variations in sheet thickness to develop into major disturbances with the result that disruption starts before the formation of the main break-up region. In the two-dimensional variable geometry air-blast atomizer, it is shown that the air flow is responsible for the formation of large, ordered, and small chaotic 'cell' structures.

Root-growth-inhibiting sheet

Science.gov (United States)

Burton, F.G.; Cataldo, D.A.; Cline, J.F.; Skiens, W.E.; Van Voris, P.

1993-01-26

In accordance with this invention, a porous sheet material is provided at intervals with bodies of a polymer which contain a 2,6-dinitroaniline. The sheet material is made porous to permit free passage of water. It may be either a perforated sheet or a woven or non-woven textile material. A particularly desirable embodiment is a non-woven fabric of non-biodegradable material. This type of material is known as a geotextile'' and is used for weed control, prevention of erosion on slopes, and other landscaping purposes. In order to obtain a root repelling property, a dinitroaniline is blended with a polymer which is attached to the geotextile or other porous material.

Root-growth-inhibiting sheet

Science.gov (United States)

Burton, Frederick G.; Cataldo, Dominic A.; Cline, John F.; Skiens, W. Eugene; Van Voris, Peter

1993-01-01

In accordance with this invention, a porous sheet material is provided at intervals with bodies of a polymer which contain a 2,6-dinitroaniline. The sheet material is made porous to permit free passage of water. It may be either a perforated sheet or a woven or non-woven textile material. A particularly desirable embodiment is a non-woven fabric of non-biodegradable material. This type of material is known as a "geotextile" and is used for weed control, prevention of erosion on slopes, and other landscaping purposes. In order to obtain a root repelling property, a dinitroaniline is blended with a polymer which is attached to the geotextile or other porous material.

Mobility Balance Sheet 2009

International Nuclear Information System (INIS)

Jorritsma, P.; Derriks, H.; Francke, J.; Gordijn, H.; Groot, W.; Harms, L.; Van der Loop, H.; Peer, S.; Savelberg, F.; Wouters, P.

2009-06-01

The Mobility Balance Sheet provides an overview of the state of the art of mobility in the Netherlands. In addition to describing the development of mobility this report also provides explanations for the growth of passenger and freight transport. Moreover, the Mobility Balance Sheet also focuses on a topical theme: the effects of economic crises on mobility. [nl

Safety advice sheets

CERN Multimedia

HSE Unit

2013-01-01

You never know when you might be faced with questions such as: when/how should I dispose of a gas canister? Where can I find an inspection report? How should I handle/store/dispose of a chemical substance…?   The SI section of the DGS/SEE Group is primarily responsible for safety inspections, evaluating the safety conditions of equipment items, premises and facilities. On top of this core task, it also regularly issues “Safety Advice Sheets” on various topics, designed to be of assistance to users but also to recall and reinforce safety rules and procedures. These clear and concise sheets, complete with illustrations, are easy to display in the appropriate areas. The following safety advice sheets have been issued so far: Other sheets will be published shortly. Suggestions are welcome and should be sent to the SI section of the DGS/SEE Group. Please send enquiries to general-safety-visits.service@cern.ch.

Manifold free multiple sheet superplastic forming

Science.gov (United States)

Elmer, John W.; Bridges, Robert L.

2004-01-13

Fluid-forming compositions in a container attached to enclosed adjacent sheets are heated to relatively high temperatures to generate fluids (gases) that effect inflation of the sheets. Fluid rates to the enclosed space between the sheets can be regulated by the canal from the container. Inflated articles can be produced by a continuous, rather than batch-type, process.

21 CFR 880.5180 - Burn sheet.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Burn sheet. 880.5180 Section 880.5180 Food and... Burn sheet. (a) Identification. A burn sheet is a device made of a porous material that is wrapped aroung a burn victim to retain body heat, to absorb wound exudate, and to serve as a barrier against...

Sheet-bulk metal forming – forming of functional components from sheet metals

Directory of Open Access Journals (Sweden)

Merklein Marion

2015-01-01

Full Text Available The paper gives an overview on the application of sheet-bulk metal forming operations in both scientific and industrial environment. Beginning with the need for an innovative forming technology, the definition of this new process class is introduced. The rising challenges of the application of bulk metal forming operations on sheet metals are presented and the demand on a holistic investigation of this topic is motivated. With the help of examples from established production processes, the latest state of technology and the lack on fundamental knowledge is shown. Furthermore, perspectives regarding new research topics within sheet-bulk metal forming are presented. These focus on processing strategies to improve the quality of functional components by the application of process-adapted semi-finished products as well as the local adaption of the tribological system.

Reconstructing the last Irish Ice Sheet 2: a geomorphologically-driven model of ice sheet growth, retreat and dynamics

Science.gov (United States)

Greenwood, Sarah L.; Clark, Chris D.

2009-12-01

The ice sheet that once covered Ireland has a long history of investigation. Much prior work focussed on localised evidence-based reconstructions and ice-marginal dynamics and chronologies, with less attention paid to an ice sheet wide view of the first order properties of the ice sheet: centres of mass, ice divide structure, ice flow geometry and behaviour and changes thereof. In this paper we focus on the latter aspect and use our new, countrywide glacial geomorphological mapping of the Irish landscape (>39 000 landforms), and our analysis of the palaeo-glaciological significance of observed landform assemblages (article Part 1), to build an ice sheet reconstruction yielding these fundamental ice sheet properties. We present a seven stage model of ice sheet evolution, from initiation to demise, in the form of palaeo-geographic maps. An early incursion of ice from Scotland likely coalesced with local ice caps and spread in a south-westerly direction 200 km across Ireland. A semi-independent Irish Ice Sheet was then established during ice sheet growth, with a branching ice divide structure whose main axis migrated up to 140 km from the west coast towards the east. Ice stream systems converging on Donegal Bay in the west and funnelling through the North Channel and Irish Sea Basin in the east emerge as major flow components of the maximum stages of glaciation. Ice cover is reconstructed as extending to the continental shelf break. The Irish Ice Sheet became autonomous (i.e. separate from the British Ice Sheet) during deglaciation and fragmented into multiple ice masses, each decaying towards the west. Final sites of demise were likely over the mountains of Donegal, Leitrim and Connemara. Patterns of growth and decay of the ice sheet are shown to be radically different: asynchronous and asymmetric in both spatial and temporal domains. We implicate collapse of the ice stream system in the North Channel - Irish Sea Basin in driving such asymmetry, since rapid

Pre-LGM Northern Hemisphere ice sheet topography

Directory of Open Access Journals (Sweden)

J. Kleman

2013-10-01

Full Text Available We here reconstruct the paleotopography of Northern Hemisphere ice sheets during the glacial maxima of marine isotope stages (MIS 5b and 4.We employ a combined approach, blending geologically based reconstruction and numerical modeling, to arrive at probable ice sheet extents and topographies for each of these two time slices. For a physically based 3-D calculation based on geologically derived 2-D constraints, we use the University of Maine Ice Sheet Model (UMISM to calculate ice sheet thickness and topography. The approach and ice sheet modeling strategy is designed to provide robust data sets of sufficient resolution for atmospheric circulation experiments for these previously elusive time periods. Two tunable parameters, a temperature scaling function applied to a spliced Vostok–GRIP record, and spatial adjustment of the climatic pole position, were employed iteratively to achieve a good fit to geological constraints where such were available. The model credibly reproduces the first-order pattern of size and location of geologically indicated ice sheets during marine isotope stages (MIS 5b (86.2 kyr model age and 4 (64 kyr model age. From the interglacial state of two north–south obstacles to atmospheric circulation (Rocky Mountains and Greenland, by MIS 5b the emergence of combined Quebec–central Arctic and Scandinavian–Barents-Kara ice sheets had increased the number of such highland obstacles to four. The number of major ice sheets remained constant through MIS 4, but the merging of the Cordilleran and the proto-Laurentide Ice Sheet produced a single continent-wide North American ice sheet at the LGM.

Electrochemical bisphenol A sensor based on N-doped graphene sheets

International Nuclear Information System (INIS)

Fan Haixia; Li Yan; Wu Dan; Ma Hongmin; Mao Kexia; Fan Dawei; Du Bin; Li He; Wei Qin

2012-01-01

Highlights: ► N-doped graphene sheets have catalytic activity towards the BPA oxidation. ► The biosensor based on N-doped graphene sheets and chitosan. ► This method was proposed for determination of BPA utilizing N-doped graphene sheets. - Abstract: Bisphenol A (BPA), which could disrupt endocrine system and cause cancer, has been considered as an endocrine disruptor. Therefore, it is very important and necessary to develop a sensitive and selective method for detection of BPA. Herein, nitrogen-doped graphene sheets (N-GS) and chitosan (CS) were used to prepare electrochemical BPA sensor. Compared with graphene, N-GS has favorable electron transfer ability and electrocatalytic property, which could enhance the response signal towards BPA. CS also exhibits excellent film forming ability and improves the electrochemical behavior of N-GS modified electrode. The sensor exhibits a sensitive response to BPA in the range of 1.0 × 10 −8 –1.3 × 10 −6 mol L −1 with a low detection limit of 5.0 × 10 −9 mol L −1 under the optimal conditions. Finally, this proposed sensor was successfully employed to determine BPA in water samples with satisfactory results.

Intermontane eolian sand sheet development, Upper Tulum Valley, central-western Argentina

Directory of Open Access Journals (Sweden)

Patrick Francisco Fuhr Dal' Bó

Full Text Available ABSTRACTThe intermontane Upper Tulum eolian sand sheet covers an area of ca. 125 km² at north of the San Juan Province, central-western Argentina. The sand sheet is currently an aggrading system where vegetation cover, surface cementation and periodic flooding withhold the development of dunes with slipfaces. The sand sheet surface is divided into three parts according to the distribution of sedimentary features, which reflects the variation in sediment budget, water table level and periodic flooding. The central sand sheet part is the main area of eolian deposition and is largely stabilized by vegetation. The sedimentary succession is 4 m thick and records the vertical interbedding of eolian and subaqueous deposits, which have been deposited for at least 3.6 ky with sedimentation rates of 86.1 cm/ky. The construction of the sand sheet is associated with deflation of the sand-graded debris sourced by San Juan alluvial fan, which is available mainly in drier fall-winter months where water table is lower and wind speeds are periodically above the threshold velocity for sand transport. The accumulation of sedimentary bodies occurs in a stabilized eolian system where vegetation cover, thin mud veneers and surface cementation are the main agents in promoting accumulation. The preservation of the sand sheet accumulations is enabled by the progressive creation of the accommodation space in a tectonically active basin and the continuous burial of geological bodies favored by high rates of sedimentation.

Research on Al-alloy sheet forming formability during warm/hot sheet hydroforming based on elliptical warm bulging test

Science.gov (United States)

Cai, Gaoshen; Wu, Chuanyu; Gao, Zepu; Lang, Lihui; Alexandrov, Sergei

2018-05-01

An elliptical warm/hot sheet bulging test under different temperatures and pressure rates was carried out to predict Al-alloy sheet forming limit during warm/hot sheet hydroforming. Using relevant formulas of ultimate strain to calculate and dispose experimental data, forming limit curves (FLCS) in tension-tension state of strain (TTSS) area are obtained. Combining with the basic experimental data obtained by uniaxial tensile test under the equivalent condition with bulging test, complete forming limit diagrams (FLDS) of Al-alloy are established. Using a quadratic polynomial curve fitting method, material constants of fitting function are calculated and a prediction model equation for sheet metal forming limit is established, by which the corresponding forming limit curves in TTSS area can be obtained. The bulging test and fitting results indicated that the sheet metal FLCS obtained were very accurate. Also, the model equation can be used to instruct warm/hot sheet bulging test.

Data analysis & probability drill sheets : grades 6-8

CERN Document Server

Forest, Chris

2011-01-01

For grades 6-8, our Common Core State Standards-based resource meets the data analysis & probability concepts addressed by the NCTM standards and encourages your students to review the concepts in unique ways. Each drill sheet contains warm-up and timed drill activities for the student to practice data analysis & probability concepts.

On Jovian plasma sheet structure

International Nuclear Information System (INIS)

Khurana, K.K.; Kivelson, M.G.

1989-01-01

The authors evaluate several models of Jovian plasma sheet structure by determining how well they organize several aspects of the observed Voyager 2 magnetic field characteristics as a function of Jovicentric radial distance. It is shown that in the local time sector of the Voyager 2 outbound pass (near 0300 LT) the published hinged-magnetodisc models with wave (i.e., models corrected for finite wave velocity effects) are more successful than the published magnetic anomaly model in predicting locations of current sheet crossings. They also consider the boundary between the plasma sheet and the magnetotail lobe which is expected to vary slowly with radial distance. They use this boundary location as a further test of the models of the magnetotail. They show that the compressional MHD waves have much smaller amplitude in the lobes than in the plasma sheet and use this criterion to refine the identification of the plasma-sheet-lobe boundary. When the locations of crossings into and out of the lobes are examined, it becomes evident that the magnetic-anomaly model yields a flaring plasma sheet with a halfwidth of ∼ 3 R J at a radial distance of 20 R J and ∼ 12 R J at a radial distance of 100 R J . The hinged-magnetodisc models with wave, on the other hand, predict a halfwidth of ∼ 3.5 R J independent of distance beyond 20 R J . New optimized versions of the two models locate both the current sheet crossings and lobe encounters equally successfully. The optimized hinged-magnetodisc model suggests that the wave velocity decreases with increasing radial distance. The optimized magnetic anomaly model yields lower velocity contrast than the model of Vasyliunas and Dessler (1981)

Dynamic Sequence Assignment.

Science.gov (United States)

1983-12-01

D-136 548 DYNAMIIC SEQUENCE ASSIGNMENT(U) ADVANCED INFORMATION AND 1/2 DECISION SYSTEMS MOUNTAIN YIELW CA C A 0 REILLY ET AL. UNCLSSIIED DEC 83 AI/DS...I ADVANCED INFORMATION & DECISION SYSTEMS Mountain View. CA 94040 84 u ,53 V,..’. Unclassified _____ SCURITY CLASSIFICATION OF THIS PAGE REPORT...reviews some important heuristic algorithms developed for fas- ter solution of the sequence assignment problem. 3.1. DINAMIC MOGRAMUNIG FORMULATION FOR

Rubella - Fact Sheet for Parents

Science.gov (United States)

... and 4 through 6 years Fact Sheet for Parents Color [2 pages] Español: Rubéola The best way ... according to the recommended schedule. Fact Sheets for Parents Diseases and the Vaccines that Prevent Them Chickenpox ...

Prototypical model for tensional wrinkling in thin sheets

KAUST Repository

Davidovitch, B.; Schroll, R. D.; Vella, D.; Adda-Bedia, M.; Cerda, E. A.

2011-01-01

The buckling and wrinkling of thin films has recently seen a surge of interest among physicists, biologists, mathematicians, and engineers. This activity has been triggered by the growing interest in developing technologies at ever-decreasing scales and the resulting necessity to control the mechanics of tiny structures, as well as by the realization that morphogenetic processes, such as the tissue-shaping instabilities occurring in animal epithelia or plant leaves, often emerge from mechanical instabilities of cell sheets. Although the most basic buckling instability of uniaxially compressed plates was understood by Euler more than two centuries ago, recent experiments on nanometrically thin (ultrathin) films have shown significant deviations from predictions of standard buckling theory. Motivated by this puzzle, we introduce here a theoretical model that allows for a systematic analysis of wrinkling in sheets far from their instability threshold. We focus on the simplest extension of Euler buckling that exhibits wrinkles of finite length--a sheet under axisymmetric tensile loads. The first study of this geometry, which is attributed to Lamé, allows us to construct a phase diagram that demonstrates the dramatic variation of wrinkling patterns from near-threshold to far-from-threshold conditions. Theoretical arguments and comparison to experiments show that the thinner the sheet is, the smaller is the compressive load above which the far-from-threshold regime emerges. This observation emphasizes the relevance of our analysis for nanomechanics applications.

Prototypical model for tensional wrinkling in thin sheets

KAUST Repository

Davidovitch, B.

2011-10-31

The buckling and wrinkling of thin films has recently seen a surge of interest among physicists, biologists, mathematicians, and engineers. This activity has been triggered by the growing interest in developing technologies at ever-decreasing scales and the resulting necessity to control the mechanics of tiny structures, as well as by the realization that morphogenetic processes, such as the tissue-shaping instabilities occurring in animal epithelia or plant leaves, often emerge from mechanical instabilities of cell sheets. Although the most basic buckling instability of uniaxially compressed plates was understood by Euler more than two centuries ago, recent experiments on nanometrically thin (ultrathin) films have shown significant deviations from predictions of standard buckling theory. Motivated by this puzzle, we introduce here a theoretical model that allows for a systematic analysis of wrinkling in sheets far from their instability threshold. We focus on the simplest extension of Euler buckling that exhibits wrinkles of finite length--a sheet under axisymmetric tensile loads. The first study of this geometry, which is attributed to Lamé, allows us to construct a phase diagram that demonstrates the dramatic variation of wrinkling patterns from near-threshold to far-from-threshold conditions. Theoretical arguments and comparison to experiments show that the thinner the sheet is, the smaller is the compressive load above which the far-from-threshold regime emerges. This observation emphasizes the relevance of our analysis for nanomechanics applications.

Dynamic online peer evaluations to improve group assignments in nursing e-learning environment.

Science.gov (United States)

Adwan, Jehad

2016-06-01

The purpose of this research was to evaluate the use of online peer evaluation forms for online group activities in improving group project outcomes. The investigator developed and used a web-based Google Forms® self and peer evaluation form of 2 group assignments' rubric for junior and senior nursing students. The form covered elements of the assignments including: research activity, analysis of the literature, writing of report, participation in making of presentation, overall contribution to the project, and participation in the weekly group discussions. Items were rated from 1 (did not contribute) to 5 (outstanding contribution) in addition to NA when one activity did not apply. The self and peer evaluation process was conducted twice: once after group assignment 1 and once after group assignment 2. The group assignments final products were done in the form of VoiceThread online presentations that were shared with the rest of the class reflecting the groups' work on a health informatics topic of interest. Data collected as the students completed self and peer evaluations for group assignments 1 and 2. Also, optional comments regarding member performance were collected to add contextual information in addition to ratings. Students received credit for completing the peer evaluations and the grade for the particular assignment was affected by their performance based on peer evaluations of their contributions. Students' peer evaluations showed in a color-coded spreadsheet which enabled the course faculty to view real time results of students' ratings after each assignment. The faculty provided timely and tailored feedback to groups or individuals as needed, using positive feedback and commending high performance while urging struggling individual students and groups to improve lower ratings in specific areas. Comparing evaluations of both assignments, there were statistically significant improvements among all students. The mean scores of the entire sample were

A Synthesis of the Basal Thermal State of the Greenland Ice Sheet

Science.gov (United States)

Macgregor, J. A.; Fahnestock, M. A.; Catania, G. A.; Aschwanden, A.; Clow, G. D.; Colgan, W. T.; Gogineni, S. P.; Morlighem, M.; Nowicki, S. M. J.; Paden, J. D.;

Plasma sheet fast flows and auroral dynamics during substorm: a case study

Directory of Open Access Journals (Sweden)

N. L. Borodkova

2002-03-01

Full Text Available Interball-1 observations of a substorm development in the mid-tail on 16 December 1998 are compared with the auroral dynamics obtained from the Polar UV imager. Using these data, the relationship between plasma flow directions in the tail and the location of the auroral activation is examined. Main attention is given to tailward and earth-ward plasma flows, interpreted as signatures of a Near Earth Neutral Line (NENL. It is unambiguously shown that in the mid-plasma sheet the flows were directed tailward when the auroral bulge developed equatorward of the spacecraft ionospheric footprint. On the contrary, when active auroras moved poleward of the Interball-1 projection, earthward fast flow bursts were observed. This confirms the concept that the NENL (or flow reversal region is the source of auroras forming the poleward edge of the auroral bulge. The observed earthward flow bursts have all typical signatures of Bursty Bulk Flows (BBFs, described by Angelopolous et al. (1992. These BBFs are related to substorm activations starting at the poleward edge of the expanded auroral bulge. We interpret the BBFs as a result of reconnection pulses occurring tail-ward of Interball-1. In addition, some non-typically observed phenomena were detected in the plasma sheet during this substorm: (i tailward/earthward flows were superimposed on a very strong duskward flow, and (ii wavy structures of both magnetic field and plasma density were registered. The latter observation is probably linked to the filamentary structure of the current sheet.Key words. Magnetospheric physics (auroral phenomena; plasma sheet; storms and substorms

Cell sheet technology and cell patterning for biofabrication

Energy Technology Data Exchange (ETDEWEB)

Hannachi, Imen Elloumi; Yamato, Masayuki; Okano, Teruo [Institute of Advanced Biomedical Engineering and Science, Tokyo Women' s Medical University, 8-1 Kawada-cho, Shinjuku, Tokyo (Japan)

2009-06-01

We have developed cell sheet technology as a modern method for the fabrication of functional tissue-like and organ-like structures. This technology allows for a sheet of interconnected cells and cells in full contact with their natural extracellular environment to be obtained. A cell sheet can be patterned and composed according to more than one cell type. The key technology of cell sheet engineering is that a fabricated cell sheet can be harvested and transplanted utilizing temperature-responsive surfaces. In this review, we summarize different aspects of cell sheet engineering and provide a survey of the application of cell sheets as a suitable material for biofabrication and clinics. Moreover, since cell micropatterning is a key tool for cell sheet engineering, in this review we focus on the introduction of our approaches to cell micropatterning and cell co-culture to the principles of automation and how they can be subjected to easy robotics programming. Finally, efforts towards making cell sheet technology suitable for biofabrication and robotic biofabrication are also summarized. (topical review)

Energy information sheets

Energy Technology Data Exchange (ETDEWEB)

1993-12-02

The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the general public. Written for the general public, the EIA publication Energy Information Sheets was developed to provide information on various aspects of fuel production, prices, consumption and capability. The information contained herein pertains to energy data as of December 1991. Additional information on related subject matter can be found in other EIA publications as referenced at the end of each sheet.

Weld Repair of Thin Aluminum Sheet

Science.gov (United States)

Beuyukian, C. S.; Mitchell, M. J.

1986-01-01

Weld repairing of thin aluminum sheets now possible, using niobium shield and copper heat sinks. Refractory niobium shield protects aluminum adjacent to hole, while copper heat sinks help conduct heat away from repair site. Technique limits tungsten/inert-gas (TIG) welding bombardment zone to melt area, leaving surrounding areas around weld unaffected. Used successfully to repair aluminum cold plates on Space Shuttle, Commercial applications, especially in sealing fractures, dents, and holes in thin aluminum face sheets or clad brazing sheet in cold plates, heat exchangers, coolers, and Solar panels. While particularly suited to thin aluminum sheet, this process also used in thicker aluminum material to prevent surface damage near weld area.

Intensity variation of cosmic rays near the heliospheric current sheet

International Nuclear Information System (INIS)

Badruddin, K.S.; Yadav, R.S.; Yadav, N.R.

1985-01-01

Cosmic ray intensity variations near the heliospheric current sheet-both above and below it-have been studied during 1964-76. Superposed epoch analysis of the cosmic ray neutron monitor data with respect to sector boundaries (i.e., heliospheric current sheet crossings) has been performed. In this analysis data from neutron monitors well distributed in latitude over the Earth's surface is used. First, this study has been made during the two solar activity minimum periods 1964-65 and 1975-76, using the data from Thule (cut-off rigidity O GV), Deep River (cut-off rigidity 1.02 GV), Rome (cut-off rigidity 6.32 GV) and Huancayo (cut-off rigidity 13.45 GV) neutron monitors. The data is analyzed from Deep River, Rome and Huancayo neutron monitors, for which data is available for the full period (1964-76), by dividing the periods according to the changes in solar activity, interplanetary magnetic field polarity and coronal holes. All these studies have shown a negative gradient with respect to heliomagnetic latitude (current sheet). These results have been discussed in the light of theoretical and observational evidences. Suggestions have been given to overcome the discrepancy between the observational and theoretical results. Further, possible explanations for these observational results have been suggested. (author)

Survey of 0.1- to 16-keV/e plasma sheet ion composition

International Nuclear Information System (INIS)

Lennartsson, W.; Shelley, E.G.

1986-01-01

A large statistical survey of the 0.1- to 16-keV/e plasma sheet ion composition has been carried out using data obtained by the Plasma Composition Experiment on ISEE 1 between 10 and 23 R/sub E/ during 1978 and 1979. This survey includes more than 10 times the quantity of data used in earlier studies of the same topic and makes it possible to investigate in finer detail the relationship between the ion composition and the substorm activity. The larger data base also makes it possible for the first time to study the spatial distribution of the principal ion species. As found in previous studies, the ion composition has a large variance at any given value of the AE index, but a number of distinct trends emerge when the data are averaged at each activity level. During quiet conditions the plasma sheet is dominated by ions of solar origin (H + and He ++ ), as found in earlier studies, and these ions are most numerous during extended periods of very low activity (AE< or approx. =30 γ). The quiet time density of these ions is particularly large in the flanks of the plasma sheet (GSM Yapprox. +- 10 R/sub E/), where it is about twice as large as it is near the central axis of the plasma sheet (Y = Z = 0). In contrast, the energy of these ions peaks near the central axis

Modeling the Alzheimer Abeta17-42 fibril architecture: tight intermolecular sheet-sheet association and intramolecular hydrated cavities.

Science.gov (United States)

Zheng, Jie; Jang, Hyunbum; Ma, Buyong; Tsai, Chung-Jun; Nussinov, Ruth

2007-11-01

We investigate Abeta(17-42) protofibril structures in solution using molecular dynamics simulations. Recently, NMR and computations modeled the Abeta protofibril as a longitudinal stack of U-shaped molecules, creating an in-parallel beta-sheet and loop spine. Here we study the molecular architecture of the fibril formed by spine-spine association. We model in-register intermolecular beta-sheet-beta-sheet associations and study the consequences of Alzheimer's mutations (E22G, E22Q, E22K, and M35A) on the organization. We assess the structural stability and association force of Abeta oligomers with different sheet-sheet interfaces. Double-layered oligomers associating through the C-terminal-C-terminal interface are energetically more favorable than those with the N-terminal-N-terminal interface, although both interfaces exhibit high structural stability. The C-terminal-C-terminal interface is essentially stabilized by hydrophobic and van der Waals (shape complementarity via M35-M35 contacts) intermolecular interactions, whereas the N-terminal-N-terminal interface is stabilized by hydrophobic and electrostatic interactions. Hence, shape complementarity, or the "steric zipper" motif plays an important role in amyloid formation. On the other hand, the intramolecular Abeta beta-strand-loop-beta-strand U-shaped motif creates a hydrophobic cavity with a diameter of 6-7 A, allowing water molecules and ions to conduct through. The hydrated hydrophobic cavities may allow optimization of the sheet association and constitute a typical feature of fibrils, in addition to the tight sheet-sheet association. Thus, we propose that Abeta fiber architecture consists of alternating layers of tight packing and hydrated cavities running along the fibrillar axis, which might be possibly detected by high-resolution imaging.

Evolution of three-dimensional relativistic current sheets and development of self-generated turbulence

Science.gov (United States)

Takamoto, M.

2018-05-01

In this paper, the temporal evolution of three-dimensional relativistic current sheets in Poynting-dominated plasma is studied for the first time. Over the past few decades, a lot of efforts have been conducted on studying the evolution of current sheets in two-dimensional space, and concluded that sufficiently long current sheets always evolve into the so-called plasmoid chain, which provides a fast reconnection rate independent of its resistivity. However, it is suspected that plasmoid chain can exist only in the case of two-dimensional approximation, and would show transition to turbulence in three-dimensional space. We performed three-dimensional numerical simulation of relativistic current sheet using resistive relativistic magnetohydrodynamic approximation. The results showed that the three-dimensional current sheets evolve not into plasmoid chain but turbulence. The resulting reconnection rate is 0.004, which is much smaller than that of plasmoid chain. The energy conversion from magnetic field to kinetic energy of turbulence is just 0.01 per cent, which is much smaller than typical non-relativistic cases. Using the energy principle, we also showed that the plasmoid is always unstable for a displacement in the opposite direction to its acceleration, probably interchange-type instability, and this always results in seeds of turbulence behind the plasmoids. Finally, the temperature distribution along the sheet is discussed, and it is found that the sheet is less active than plasmoid chain. Our finding can be applied for many high-energy astrophysical phenomena, and can provide a basic model of the general current sheet in Poynting-dominated plasma.

Predicting Hot Deformation of AA5182 Sheet

Science.gov (United States)

Lee, John T.; Carpenter, Alexander J.; Jodlowski, Jakub P.; Taleff, Eric M.

Aluminum 5000-series alloy sheet materials exhibit substantial ductilities at hot and warm temperatures, even when grain size is not particularly fine. The relatively high strain-rate sensitivity exhibited by these non-superplastic materials, when deforming under solute-drag creep, is a primary contributor to large tensile ductilities. This active deformation mechanism influences both plastic flow and microstructure evolution across conditions of interest for hot- and warm-forming. Data are presented from uniaxial tensile and biaxial bulge tests of AA5182 sheet material at elevated temperatures. These data are used to construct a material constitutive model for plastic flow, which is applied in finite-element-method (FEM) simulations of plastic deformation under multiaxial stress states. Simulation results are directly compared against experimental data to explore the usefulness of this constitutive model. The effects of temperature and stress state on plastic response and microstructure evolution are discussed.

Sheet pinch devices

International Nuclear Information System (INIS)

Anderson, O.A.; Baker, W.R.; Ise, J. Jr.; Kunkel, W.B.; Pyle, R.V.; Stone, J.M.

1958-01-01

Three types of sheet-like discharges are being studied at Berkeley. The first of these, which has been given the name 'Triax', consists of a cylindrical plasma sleeve contained between two coaxial conducting cylinders A theoretical analysis of the stability of the cylindrical sheet plasma predicts the existence of a 'sausage-mode' instability which is, however, expected to grow more slowly than in the case of the unstabilized linear pinch (by the ratio of the radial dimensions). The second pinch device employs a disk shaped discharge with radial current guided between flat metal plates, this configuration being identical to that of the flat hydromagnetic capacitor without external magnetic field. A significant feature of these configurations is the absence of a plasma edge, i.e., there are no regions of sharply curved magnetic field lines anywhere in these discharges. The importance of this fact for stability is not yet fully investigated theoretically. As a third configuration a rectangular, flat pinch tube has been constructed, and the behaviour of a flat plasma sheet with edges is being studied experimentally

Participation in Sports and Civic Engagement. Fact Sheet

Science.gov (United States)

Lopez, Mark Hugo; Moore, Kimberlee

2006-01-01

One reason to offer sports in school is to teach youth the values, skills, and habits that will make them more active, engaged, and responsible citizens. Past evidence on the civic effects of sports is mixed, but points to some potential positive civic effects. This fact sheet uses recent data from the 2002 National Youth Survey of Civic…

Understanding the adsorptive interactions of arsenate-iron nanoparticles with curved fullerene-like sheets in activated carbon using a quantum mechanics/molecular mechanics computational approach.

Science.gov (United States)

Ha, Nguyen Ngoc; Cam, Le Minh; Ha, Nguyen Thi Thu; Goh, Bee-Min; Saunders, Martin; Jiang, Zhong-Tao; Altarawneh, Mohammednoor; Dlugogorski, Bogdan Z; El-Harbawi, Mohanad; Yin, Chun-Yang

2017-06-07

The prevalence of global arsenic groundwater contamination has driven widespread research on developing effective treatment systems including adsorption using various sorbents. The uptake of arsenic-based contaminants onto established sorbents such as activated carbon (AC) can be effectively enhanced via immobilization/impregnation of iron-based elements on the porous AC surface. Recent suggestions that AC pores structurally consist of an eclectic mix of curved fullerene-like sheets may affect the arsenic adsorption dynamics within the AC pores and is further complicated by the presence of nano-sized iron-based elements. We have therefore, attempted to shed light on the adsorptive interactions of arsenate-iron nanoparticles with curved fullerene-like sheets by using hybridized quantum mechanics/molecular mechanics (QMMM) calculations and microscopy characterization. It is found that, subsequent to optimization, chemisorption between HAsO 4 2- and the AC carbon sheet (endothermic process) is virtually non-existent - this observation is supported by experimental results. Conversely, the incorporation of iron nanoparticles (FeNPs) into the AC carbon sheet greatly facilitates chemisorption of HAsO 4 2- . Our calculation implies that iron carbide is formed at the junction between the iron and the AC interface and this tightly chemosorbed layer prevents detachment of the FeNPs on the AC surface. Other aspects including electronic structure/properties, carbon arrangement defects and rate of adsorptive interaction, which are determined using the Climbing-Image NEB method, are also discussed.

SU-F-T-550: Radiochromic Plastic Thin Sheet Dosimeter: Initial Performance

Energy Technology Data Exchange (ETDEWEB)

Jordan, K [London Regional Cancer Program, London, ON (United Kingdom); Adamovics, J [John Adamovics, Skillman, NJ (United States)

2016-06-15

Purpose: Thin sheets, of a high sensitivity formulation of radiochromic dosimeter, Presage were prepared and evaluated for optical readout. Methods: Sheets of radiochromic polyurethane, 12 cm long, 10 cm wide and 0.2 cm thick were prepared with leuco crystal violet as the reporter molecule. Sample transmission was evaluated at a wavelength of 590 nm with in-house constructed instruments: optical cone beam laser CT scanner, fixed and scanning spot densitometers. Sample sequential irradiations to a total dose of 40 Gy were conducted with a modified, Theratron 60, cobalt radiotherapy machine at dose rates of 1 or 0.25 Gy per minute. Exposure to ambient and readout light was minimized to limit background photochromic signals. Samples were stored at 4°C. Optical activity was assessed from linearly polarized transmission images. Comparison sensitivity measurements with EBT3 film were conducted. Results: Samples were transparent, smooth and pale purple before irradiation. Radiochromic reaction was completed in less than 5 minutes. A linear dose response with a sensitivity of 0.5 cm-1Gy-1 was observed. Micrometer measurements found sheet thickness variations up to 20%. Uniform dose, 2 Gy attenuation images, correlated with local sheet thicknesses. Comparable measurements with EBT3 film were 3 times more sensitive at 1 Gy but above 15 Gy, EBT3 film had lower sensitivity than 0.2 cm thick Presage sheet dosimeter due to its non-linear response. Conclusion: Dose sensitivity provided a 10% decrease in transmission for a 1 Gy dose. Improvements in mold design are expected to allow production of sheets with less than 5% variation in thickness. Above, 10 Gy, Presage sheet dosimeter performance expected to exceed EBT3 film based on linearity, sensitivity, transparency and smoothness of samples. J Adamovics is owner of Heuris Inc.

ICESat's First Year of Measurements Over the Polar Ice Sheets

Science.gov (United States)

Shuman, C. A.

2004-05-01

NASA's Ice, Cloud and Land Elevation Satellite (ICESat) mission was developed to measure changes in elevation of the Greenland and Antarctic ice sheets. Its primary mission goal is to significantly refine estimates of polar ice sheet mass balance. Obtaining precise, spatially dense, ice sheet elevations through time is the first step towards this goal. ICESat data will then enable study of associations between observed ice changes and dynamic or climatic forcing factors, and thus enable improved estimation of the present and future contributions of the ice sheets to global sea level rise. ICESat was launched on January 12, 2003 and acquired science data from February 20th to March 29th with the first of the three lasers of the Geoscience Laser Altimeter System (GLAS). Data acquisition with the second laser began on September 25th and continued until November 18th, 2003. For one-year change detection, the second laser is scheduled for operation from approximately February 17th to March 20th, 2004. Additional operational periods will be selected to 1) enable periodic measurements through the year, and 2) to support of other NASA Earth Science Enterprise missions and activities. To obtain these precise ice sheet elevations, GLAS has a 1064 nm wavelength laser operating at 40 Hz with a designed range precision of about 10 cm. The laser footprints are about 70 m in diameter on the Earth's surface and are spaced every 172 m along-track. The on-board GPS receiver enables radial orbit determinations to an accuracy better than 5 cm. The star-tracking attitude-determination system will enable laser footprints to be located to 6 m horizontally when attitude calibration is completed. The orbital altitude averages 600 km at an inclination of 94 degrees with coverage extending from 86 degrees N and S latitude. The spacecraft attitude can be controlled to point the laser beam to within 50 m of surface reference tracks over the ice sheets and to point off-nadir up to 5 degrees to

Eliminating Heavy Metals from Water with NanoSheet Minerals as Adsorbents

Directory of Open Access Journals (Sweden)

Shaoxian Song

2017-12-01

Full Text Available Heavy metals usually referred to those with atomic weights ranging from 63.5 to 200.6. Because of natural-mineral dissolution and human activities such as mining, pesticides, fertilizer, metal planting and batteries manufacture, etc., these heavy metals, including zinc, copper, mercury, lead, cadmium and chromium have been excessively released into water courses, like underground water, lake and river, etc. The ingestion of the heavy metals-contaminated water would raise serious health problems to human beings even at a low concentration. For instance, lead can bring human beings about barrier to the normal function of kidney, liver and reproductive system, while zinc can cause stomach cramps, skin irritations, vomiting and anemia. Mercury is a horrible neurotoxin that may result in damages to the central nervous system, dysfunction of pulmonary and kidney, chest and dyspnea. Chromium (VI has been proved can cause many diseases ranging from general skin irritation to severe lung carcinoma. Accordingly, the World Health Organization announced the maximum contaminant levels (MCL for the heavy metals in drinking water. There are numerous processes for eliminating heavy metals from water in order to provide citizens safe drinking water, including precipitation, adsorption, ion exchange, membrane separation and biological treatment, etc. Adsorption is considered as a potential process for deeply removing heavy metals, in which the selection of adsorbents plays a predominant role. Nano-sheet minerals as the adsorbents are currently the hottest researches in the field. They are obtained from layered minerals, such as montmorillonite, graphite and molybdenite, through the processing of intercalation, electrochemical and mechanical exfoliation, etc. Nano-sheet minerals are featured by their large specific surface area, relatively low costs and active adsorbing sites, leading to be effective and potential adsorbents for heavy metals removal from water

Settlement during vibratory sheet piling

NARCIS (Netherlands)

Meijers, P.

2007-01-01

During vibratory sheet piling quite often the soil near the sheet pile wall will settle. In many cases this is not a problem. For situations with houses, pipelines, roads or railroads at relative short distance these settlements may not be acceptable. The purpose of the research described in this

Controlling microstructure and texture in magnesium alloy sheet by shear-based deformation processing

Science.gov (United States)

Sagapuram, Dinakar

Application of lightweight Mg sheet is limited by its low workability, both in production of sheet (typically by multistep hot and cold-rolling) and forming of sheet into components. Large strain extrusion machining (LSEM), a constrained chip formation process, is used to create Mg alloy AZ31B sheet in a single deformation step. The deformation in LSEM is shown to be intense simple shear that is confined to a narrow zone, which results in significant deformation-induced heating up to ~ 200°C and reduces the need for pre-heating to realize continuous sheet forms. This study focuses on the texture and microstructure development in the sheet processed by LSEM. Interestingly, deep, highly twinned steady-state layer develops in the workpiece subsurface due to the compressive field ahead of the shear zone. The shear deformation, in conjunction with this pre-deformed twinned layer, results in tilted-basal textures in the sheet with basal planes tilted well away from the surface. These textures are significantly different from those in rolled sheet, where basal planes are nearly parallel to the surface. By controlling the strain path, the basal plane inclination from the surface could be varied in the range of 32-53°. B-fiber (basal plane parallel to LSEM shear plane), associated with basal slip, is the major texture component in the sheet. An additional minor C2-fiber component appears above 250°C due to the thermal activation of pyramidal slip. Together with these textures, microstructure ranges from severely cold-worked to (dynamically) recrystallized type, with the corresponding grain sizes varying from ultrafine- (~ 200 nm) to fine- (2 mum) grained. Small-scale limiting dome height (LDH) confirmed enhanced formability (~ 50% increase in LDH) of LSEM sheet over the conventional rolled sheet. Premature, twinning-driven shear fractures are observed in the rolled sheet with the basal texture. In contrast, LSEM sheet with a tilted-basal texture favorably oriented for

Myosin II activity is required for functional leading-edge cells and closure of epidermal sheets in fish skin ex vivo.

Science.gov (United States)

Morita, Toshiyuki; Tsuchiya, Akiko; Sugimoto, Masazumi

2011-09-01

Re-epithelialization in skin wound healing is a process in which epidermal sheets grow and close the wound. Although the actin-myosin system is thought to have a pivotal role in re-epithelialization, its role is not clear. In fish skin, re-epithelialization occurs around 500 μm/h and is 50 times faster than in mammalian skin. We had previously reported that leading-edge cells of the epidermal outgrowth have both polarized large lamellipodia and "purse string"-like actin filament cables in the scale-skin culture system of medaka fish, Oryzias latipes (Cell Tissue Res, 2007). The actin purse-string (APS) is a supracellular contractile machinery in which adherens junctions (AJs) link intracellular myosin II-including actin cables between neighboring cells. In this study, we developed a modified "face-to-face" scale-skin culture system as an ex vivo model to study epidermal wound healing, and examined the role of the actin-myosin system in the rapid re-epithelialization using a myosin II ATPase inhibitor, blebbistatin. A low level of blebbistatin suppressed the formation of APS and induced the dissociation of keratocytes from the leading edge without attenuating the growth of the epidermal sheet or the migration rate of solitary keratocytes. AJs in the superficial layer showed no obvious changes elicited by blebbistatin. However, two epidermal sheets without APSs did not make a closure with each other, which was confirmed by inhibiting the connecting AJs between the superficial layers. These results suggest that myosin II activity is required for functional leading-edge cells and for epidermal closure.

49 CFR 1243.2 - Condensed balance sheet.

Science.gov (United States)

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Condensed balance sheet. 1243.2 Section 1243.2... § 1243.2 Condensed balance sheet. Commencing with reports for the 3 months beginning January 1, 1972, and... hereby, required to compile and file quarterly reports of balance sheet items in accordance with...

Electron energization in the geomagnetic tail current sheet

International Nuclear Information System (INIS)

Lyons, L.R.

1984-01-01

Electron motion in the distant tail current sheet is evaluated and found to violate the guiding center approximation at energies > or approx. =100 eV. Most electrons within the energy range approx.10 -1 -10 2 keV that enter the current sheet become trapped within the magnetic field reversal region. These electrons then convect earthward and gain energy from the cross-tail electric field. If the energy spectrum of electrons entering the current sheet is similar to that of electrons from the boundary layer surrounding the magnetotail, the energy gain from the electric field produces electron energy spectra comparable to those observed in the earth's plasma sheet. Thus current sheet interactions can be a significant source of particles and energy for plasma sheet electrons as well as for plasma sheet ions. A small fraction of electrons within the current sheet has its pitch angles scattered so as to be ejected from the current sheet within the atmospheric loss cone. These electrons can account for the electron precipitation near the high-latitude boundary of energetic electrons, which is approximately isotropic in pitch angle up to at least several hundred keV. Current sheet interaction should cause approximately isotropic auroral precipitation up to several hundred keV energies, which extends to significantly lower latitudes for ions than for electrons in agreement with low-altitude satellite observations. Electron precipitation associated with diffuse aurora generally has a transition at 1-10 keV to anisotropic pitch angle distributions. Such electron precipitation cannot be explained by current sheet interactions, but it can be explained by pitch angle diffusion driven by plasma turbulence

Bessel light sheet structured illumination microscopy

Science.gov (United States)

Noshirvani Allahabadi, Golchehr

Biomedical study researchers using animals to model disease and treatment need fast, deep, noninvasive, and inexpensive multi-channel imaging methods. Traditional fluorescence microscopy meets those criteria to an extent. Specifically, two-photon and confocal microscopy, the two most commonly used methods, are limited in penetration depth, cost, resolution, and field of view. In addition, two-photon microscopy has limited ability in multi-channel imaging. Light sheet microscopy, a fast developing 3D fluorescence imaging method, offers attractive advantages over traditional two-photon and confocal microscopy. Light sheet microscopy is much more applicable for in vivo 3D time-lapsed imaging, owing to its selective illumination of tissue layer, superior speed, low light exposure, high penetration depth, and low levels of photobleaching. However, standard light sheet microscopy using Gaussian beam excitation has two main disadvantages: 1) the field of view (FOV) of light sheet microscopy is limited by the depth of focus of the Gaussian beam. 2) Light-sheet images can be degraded by scattering, which limits the penetration of the excitation beam and blurs emission images in deep tissue layers. While two-sided sheet illumination, which doubles the field of view by illuminating the sample from opposite sides, offers a potential solution, the technique adds complexity and cost to the imaging system. We investigate a new technique to address these limitations: Bessel light sheet microscopy in combination with incoherent nonlinear Structured Illumination Microscopy (SIM). Results demonstrate that, at visible wavelengths, Bessel excitation penetrates up to 250 microns deep in the scattering media with single-side illumination. Bessel light sheet microscope achieves confocal level resolution at a lateral resolution of 0.3 micron and an axial resolution of 1 micron. Incoherent nonlinear SIM further reduces the diffused background in Bessel light sheet images, resulting in

3D 14N/1H Double Quantum/1H Single Quantum Correlation Solid-State NMR for Probing Parallel and Anti-Parallel Beta-Sheet Arrangement of Oligo-Peptides at Natural Abundance.

Science.gov (United States)

Hong, You-Lee; Asakura, Tetsuo; Nishiyama, Yusuke

2018-05-08

β-sheet structure of oligo- and poly-peptides can be formed in anti-parallel (AP)- and parallel (P)-structure, which is the important feature to understand the structures. In principle, P- and AP-β-sheet structures can be identified by the presence (AP) and absence (P) of the interstrand 1HNH/1HNH correlations on a diagonal in 2D 1H double quantum (DQ)/1H single quantum (SQ) spectrum due to the different interstrand 1HNH/1HNH distances between these two arrangements. However, the 1HNH/1HNH peaks overlap to the 1HNH3+/1HNH3+ peaks, which always give cross peaks regardless of the β-sheet arrangement. The 1HNH3+/1HNH3+ peaks disturb the observation of the presence/absence of 1HNH/1HNH correlations and the assignment of 1HNH and 1HNH3+ is not always available. Here, 3D 14N/1H DQ/1H SQ correlation solid-state NMR experiments at fast magic angle spinning (70 kHz) are introduced to distinguish AP and P β-sheet structure. The 14N dimension allows the separate observation of 1HNH/1HNH peaks from 1HNH3+/1HNH3+ peaks with clear assignment of 1HNH and 1HNH3+. In addition, the high natural abundance of 1H and 14N enables 3D 14N/1H DQ/1H SQ experiments of oligo-alanines (Ala3-6) in four hours without any isotope labelling. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

State Arts Agency Fact Sheet: Support for Arts Education

Science.gov (United States)

Online Submission, 2015

2015-01-01

This national overview of state arts agency grants and services for arts education includes summary statistics and geographic distribution. The fact sheet uses data from Final Descriptive Reports of state arts agency grant-making activities submitted annually to the National Assembly of State Arts Agencies (NASAA) and the National Endowment for…

Relativistic current sheets in electron-positron plasmas

International Nuclear Information System (INIS)

Zenitani, S.

2008-01-01

The current sheet structure with magnetic field reversal is one of the fundamental structure in space and astrophysical plasmas. It draws recent attention in high-energy astrophysical settings, where relativistic electron-positron plasmas are considered. In this talk we will review the recent progress of the physical processes in the relativistic current sheet. The kinetic stability of a single current sheet, the nonlinear behavior of these instabilities, and recent challenges on the multi current sheet systems are introduced. We will also introduce some problems of magnetic reconnection in these relativistic environments. (author)

Using HL7 in hospital staff assignments.

Science.gov (United States)

Unluturk, Mehmet S

2014-02-01

Hospital staff assignments are the instructions that allocate the hospital staff members to the hospital beds. Currently, hospital administrators make the assignments without accessing the information regarding the occupancy of the hospital beds and the acuity of the patient. As a result, administrators cannot distinguish between occupied and unoccupied beds, and may therefore assign staff to unoccupied beds. This gives rise to uneven and inefficient staff assignments. In this paper, the hospital admission-discharge-transfer (ADT) system is employed both as a data source and an assignment device to create staff assignments. When the patient data is newly added or modified, the ADT system updates the assignment software client with the relevant data. Based on the relevant data, the assignment software client is able to construct staff assignments in a more efficient way. © 2013 Elsevier Ltd. All rights reserved.

Tube sheet design for PFBR steam generator

International Nuclear Information System (INIS)

Chellapandi, P.; Chetal, S.C.; Bhoje, S.B.

1991-01-01

Top and bottom tube sheets of PFBR Steam Generators have been analysed with 3D and axisymmetric models using CASTEM Programs. Analysis indicates that the effects of piping reactions at the inlet/outlet nozzles on the primary stresses in the tube sheets are negligible and the asymmetricity of the deformation pattern introduced in the tube sheet by the presence of inlet/outlet and manhole nozzles is insignificant. The minimum tube sheet thicknesses for evaporator and reheater are 135 mm and 75 mm respectively. Further analysis has indicated the minimum fillet radius at the junction of tube sheet and dished end should be 20 mm. Simplified methodology has been developed to arrive at the number of thermal baffles required to protect the tube sheet against fatigue damage due to thermal transient. This method has been applied to PFBR steam generators to determine the required number of thermal baffles. For protecting the bottom tube sheet of evaporator against the thermal shock due to feed water and secondary pump trip, one thermal shield is found to be sufficient. Further analysis is required to decide upon the actual number to take care of the severe thermal transient, following the event of sudden dumping of water/steam, immediately after the sodium-water reaction. (author)

17 CFR 210.5-02 - Balance sheets.

Science.gov (United States)

2010-04-01

... customers at the date of the balance sheet. Include a general description of the prerequisites for billing... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Balance sheets. 210.5-02... Balance sheets. The purpose of this rule is to indicate the various line items and certain additional...

Thermomechanical processing of plasma sprayed intermetallic sheets

Science.gov (United States)

Hajaligol, Mohammad R.; Scorey, Clive; Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier; Lilly, Jr., A. Clifton; German, Randall M.

2001-01-01

A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

17 CFR 210.7-03 - Balance sheets.

Science.gov (United States)

2010-04-01

... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Balance sheets. 210.7-03... 1940, AND ENERGY POLICY AND CONSERVATION ACT OF 1975 Insurance Companies § 210.7-03 Balance sheets. (a... otherwise permitted by the Commission, should appear on the face of the balance sheets and in the notes...

Disposal sheet for preventing scattering of radioactive contaminated material

International Nuclear Information System (INIS)

Miyasaka, Shun-ichi; Kurioka, Hitoshi; Nakamura, Kenjiro.

1990-01-01

Upon disposal of vinyl sheets at the final stage of dismantling operation for nuclear buildings, etc., radioactive contaminated materials caused by cutting concretes, etc. remain on the sheets. In view of the above, members capable of restoring original shape due to the temperature difference are attached to the sheet main body so that the sheet main body may be folded into a bag-like shape. Since the members as described above are bent upon temperature elevation in the sheets, the sheet main body is pulled by the members and then spontaneously folded into a bag-like shape. As a result, the radioactive contaminated materials remaining on the sheets are wrapped into the sheet main body free from touch to operator's hands or without scattering to the surrounding. This can prevent operator's external and internal exposure. (T.M.)

Welding.

Science.gov (United States)

Cowan, Earl; And Others

The curriculum guide for welding instruction contains 16 units presented in six sections. Each unit is divided into the following areas, each of which is color coded: terminal objectives, specific objectives, suggested activities, and instructional materials; information sheet; transparency masters; assignment sheet; test; and test answers. The…

Single Point Incremental Forming using a Dummy Sheet

DEFF Research Database (Denmark)

Skjødt, Martin; Silva, Beatriz; Bay, Niels

2007-01-01

A new version of single point incremental forming (SPIF) is presented. This version includes a dummy sheet on top of the work piece, thus forming two sheets instead of one. The dummy sheet, which is in contact with the rotating tool pin, is discarded after forming. The new set-up influences....... The possible influence of friction between the two sheets is furthermore investigated. The results show that the use of a dummy sheet reduces wear of the work piece to almost zero, but also causes a decrease in formability. Bulging of the planar sides of the pyramid is reduced and surface roughness...

ESR in a disordered network of nanographene sheets

Science.gov (United States)

Hagiwara, M.; Tsugeno, H.; Yamaguchi, H.; Joly, V. L. J.; Takai, K.; Enoki, T.

2011-12-01

Randomly networked nanographene sheets have been studied by electron spin resonance (ESR) technique at 20 GHz (K-band) and 35 GHz (Q-band). Nanographene has spin-polarized non-bonding π-electron states (edge-state spins) localized in the zigzag edge region. We have investigated the temperature dependence of an ESR signal of activated carbon fibers at two different microwave powers for each frequency. The signal intensity smoothly increases with decreasing temperature at any microwave power. The line width of ESR signal with a Lorentzian line shape decreases linearly upon cooling, and then increases steeply after taking a minimum at about 20 K irrespective of microwave power. The former is interpreted as the Korringa relation in the localized edge spins and conduction π carriers. The latter may be caused by inhomogeneous line broadening of the ESR signal from randomly distributed nanographene sheets with different sizes due to the suppression of electron hopping between nanographene sheets, i.e. electron localization. The discontinuous line broadening and the signal intensity drop at around 20 K reported in the previous X-band ESR at 1 μW were not observed, probably because of either higher microwave power than 1 μW or some amount of oxygen adsorption in our sample in the present study.

Neutron spatial distribution measurement with 6Li-contained thermoluminescent sheets

International Nuclear Information System (INIS)

Konnai, A.; Odano, N.; Sawamura, H.; Ozasa, N.; Ishikawa, Y.

2006-01-01

We have been developing a thermoluminescent (TL) sheet for photon dosimetry (TL sheet) with thermoluminescent material of LiF:Mg, Cu, P and a co-polymer of ethylene and tetrafluoroethylene. For the purpose of a development of simple method for neutron spatial distribution measurement, TL sheet for neutron detection (NTL sheet) is made by adding 94.7% enriched 6 LiF to TL sheet. TL material in TL sheet is directly excited by ionizing radiation whereas, in the case of neutron detection, TL material in NTL sheet is indirectly excited by neutron capture reaction. That is neutron distribution can be obtained with TL caused by α particle from 6 Li(n, α) 3 H reaction. Responses of NTL sheets to neutrons were examined at the neutron beam irradiation facility for Boron Neutron Capture Therapy (BNCT) in JRR-4 research reactor in Japan Atomic Energy Agency. TL and NTL sheets were exposed to striped and roundly distributed neutron fields. Attenuations of neutron flux in air and water were also observed using NTL sheets. TL sheets were also exposed on the same conditions and compared with NTL sheets. TL intensity ratios of NTL sheet to TL sheet were consistent with the calculated value from 6 Li content. Thermal neutron attenuation observed by NTL sheet also corresponded with the result measured by Au wire radioactivation and TLD chips, which were currently used in BNCT at JRR-4. These results were analyzed with by Monte Carlo simulation. The present results indicated that NTL sheet is applicable to measurement of neutron spatial distribution. (author)

Development of a Microbiology Course for Diverse Majors; Longitudinal Survey of the Use of Various Active, Problem-Based Learning Assignments

Directory of Open Access Journals (Sweden)

Diana R. Cundell

2009-12-01

Full Text Available Educators are increasingly being encouraged to use more active- and problem-based-learning techniques and assignments in the classroom to improve critical and analytical thinking skills. Active learning-based courses have been purported to be more time consuming than traditional lecture methods and for many instructors have therefore proven difficult to include in many one-semester science courses. To address this problem, a series of assignments was developed for use in a basic microbiology course involving sophomore-, junior-, and senior-level students from five different biology majors (environmental science, biology, biochemistry, premedicine, and physician assistant. Writing assignments included global, historical, and social themes for which a standardized grading format was established. Students also participated in a class debate in which the merits of the living microbial kingdoms were discussed, with only one kingdom being saved from an imaginary global catastrophe. Traditional lectures were facilitated by the use of a dedicated note packet developed by the instructor and specific for course content. Laboratories involved group analysis of mini-case history studies involving pathogenic microbes. Students’ perceptions of the subject were assessed using an exit questionnaire sent to 100 of the 174 students who had taken the course during the 5-year time period. The majority of the 64 students who responded were sophomores (78%, in keeping with the target audience, and their perception of the course’s challenge level was significantly higher (p < 0.03, 8.7 than their junior and senior counterparts (7.9. Students rated the most useful learning tools as case history studies (9.4 and the class debate (9.1, with the introduction of a dedicated microbiology links web page to the University website representing the sole component resulting in a statistically significant increase in students’ perceptions of the importance of the course (p

Vibration reduction and power generation with piezoceramic sheets mounted to a flexible shaft

NARCIS (Netherlands)

Sloetjes, P.J.; de Boer, Andries

2008-01-01

A flexible shaft with surface-mounted piezoceramic sheets and strain sensors is considered which suffers from resonance and self-excited vibration. Frequency domain models, time domain simulations, and control experiments are used to analyze active modal damping and active modal balancing methods.

The spectral stability of several sunscreening agents on stratum corneum sheets

NARCIS (Netherlands)

Kammeyer, A.; Westerhof, W.; Bolhuis, P. A.; Ris, A. J.; Hische, E. A.

1987-01-01

Synopsis Film layers of seventeen commercially available sunscreen products and sixteen active ingredients on stratum corneum sheets were spectrophotometrically monitored before and after simulated solar irradiation. Fixed irradiation doses were given within the daily terrestrial limits. From the

On the possible eigenoscillations of neutral sheets

International Nuclear Information System (INIS)

Almeida, W.A.; Costa, J.M. da; Aruquipa, E.G.; Sudano, J.P.

1974-12-01

A neutral sheet model with hyperbolic tangent equilibrium magnetic field and hyperbolic square secant density profiles is considered. It is shown that the equation for small oscillations takes the form of an eigenvalue oscillation problem. Computed eigenfrequencies of the geomagnetic neutral sheet were found to be in the range of the resonant frequencies of the geomagnetic plasma sheet computed by other authors

Sheet, ligament and droplet formation in swirling primary atomization

Directory of Open Access Journals (Sweden)

Changxiao Shao

2018-04-01

Full Text Available We report direct numerical simulations of swirling liquid atomization to understand the physical mechanism underlying the sheet breakup of a non-turbulent liquid swirling jet which lacks in-depth investigation. The volume-of-fluid (VOF method coupled with adapted mesh refinement (AMR technique in GERRIS code is employed in the present simulation. The mechanisms of sheet, ligament and droplet formation are investigated. It is observed that the olive-shape sheet structure is similar to the experimental result qualitatively. The numerical results show that surface tension, pressure difference and swirling effect contribute to the contraction and extension of liquid sheet. The ligament formation is partially at the sheet rim or attributed to the extension of liquid hole. Especially, the movement of hairpin vortex exerts by an anti-radial direction force to the sheet surface and leads to the sheet thinness. In addition, droplet formation is attributed to breakup of ligament and central sheet.

Sheet, ligament and droplet formation in swirling primary atomization

Science.gov (United States)

Shao, Changxiao; Luo, Kun; Chai, Min; Fan, Jianren

2018-04-01

We report direct numerical simulations of swirling liquid atomization to understand the physical mechanism underlying the sheet breakup of a non-turbulent liquid swirling jet which lacks in-depth investigation. The volume-of-fluid (VOF) method coupled with adapted mesh refinement (AMR) technique in GERRIS code is employed in the present simulation. The mechanisms of sheet, ligament and droplet formation are investigated. It is observed that the olive-shape sheet structure is similar to the experimental result qualitatively. The numerical results show that surface tension, pressure difference and swirling effect contribute to the contraction and extension of liquid sheet. The ligament formation is partially at the sheet rim or attributed to the extension of liquid hole. Especially, the movement of hairpin vortex exerts by an anti-radial direction force to the sheet surface and leads to the sheet thinness. In addition, droplet formation is attributed to breakup of ligament and central sheet.

A note on ranking assignments using reoptimization

DEFF Research Database (Denmark)

Pedersen, Christian Roed; Nielsen, L.R.; Andersen, K.A.

2005-01-01

We consider the problem of ranking assignments according to cost in the classical linear assignment problem. An algorithm partitioning the set of possible assignments, as suggested by Murty, is presented where, for each partition, the optimal assignment is calculated using a new reoptimization...

Copper contamination in thin stainless steel sheet

International Nuclear Information System (INIS)

Holbert, R.K. Jr.; Dobbins, A.G.; Bennett, R.K. Jr.

1986-01-01

The standard welding technique used at Oak Ridge Y-12 Plant for joining thin stainless sheet is the gas tungsten arc (GTA) welding process. One of the reoccurring problems with the sheet welds is surface cracking in the heat-affected zone (HAZ). Metallography shows that the cracks are only about 0.05 mm (0.002 in.) deep which is significant in a 0.25 mm (0.01 in.) thick sheet. Thus, welding requirements do not permit any surfacing cracking as detected by a fluorescent dye penetrant test conducted on every part after welding. Surface cracks have been found in both of the two most common weld designs in the thin sheet fabricated at the Oak Ridge Y-12 Plant. These butt joints are welded between two 0.25 mm thick stainless steel sheets and a tube with eyelet welded to a 25 mm (0.98 in.) thick sheet. The weld between the two sheets is made on a semiautomatic seam welding unit, whereas the tube-to-eyelet-to-sheet welds are done manually. The quality of both welds is very dependent on the welding procedure and the way the parts are placed in the weld fixturing. Metallographic examination has indicated that some welded parts with surface cracking in the weld region had copper particles on the surface, and the question of copper contamination has been raised. With the aid of a scanning electron microscope and an electron microprobe, the existence of copper in an around the surface cracks has been verified. The copper is on the surface of the parts prior to welding in the form of small dust particles

Competitive Traffic Assignment in Road Networks

Directory of Open Access Journals (Sweden)

Krylatov Alexander Y.

2016-09-01

Full Text Available Recently in-vehicle route guidance and information systems are rapidly developing. Such systems are expected to reduce congestion in an urban traffic area. This social benefit is believed to be reached by imposing the route choices on the network users that lead to the system optimum traffic assignment. However, guidance service could be offered by different competitive business companies. Then route choices of different mutually independent groups of users may reject traffic assignment from the system optimum state. In this paper, a game theoretic approach is shown to be very efficient to formalize competitive traffic assignment problem with various groups of users in the form of non-cooperative network game with the Nash equilibrium search. The relationships between the Wardrop’s system optimum associated with the traffic assignment problem and the Nash equilibrium associated with the competitive traffic assignment problem are investigated. Moreover, some related aspects of the Nash equilibrium and the Wardrop’s user equilibrium assignments are also discussed.

World-sheet gauge fields in superstrings

International Nuclear Information System (INIS)

Porrati, M.; Tomboulis, E.T.

1989-01-01

We investigate the introduction of world-sheet 2-dimensional gauge fields in a manner consistent with world-sheet supersymmetry. We obtain the effective string action resulting from the exact integration over the world-sheet gauge fields to show that it generally describes string models with spontaneous breaking of gauge symmetries with continuous breaking parameters. We examine the question of spacetime supersymmetry spontaneous breaking, and show that breaking with continuous, in particular arbitrarily small breaking parameters does not occur; only breaking for discrete values of parameters is possible. (orig.)

Bifurcation of Jovian magnetotail current sheet

Directory of Open Access Journals (Sweden)

P. L. Israelevich

2006-07-01

Full Text Available Multiple crossings of the magnetotail current sheet by a single spacecraft give the possibility to distinguish between two types of electric current density distribution: single-peaked (Harris type current layer and double-peaked (bifurcated current sheet. Magnetic field measurements in the Jovian magnetic tail by Voyager-2 reveal bifurcation of the tail current sheet. The electric current density possesses a minimum at the point of the Bx-component reversal and two maxima at the distance where the magnetic field strength reaches 50% of its value in the tail lobe.

Canada and the Kyoto Protocol: Fact Sheet No. 5 - Developing countries

International Nuclear Information System (INIS)

2000-11-01

This fact sheet acknowledges that global change affects developed and developing countries alike, and the fact that most developing countries do not have the human, financial and technical capacity to effectively address climate change issues without help from the industrialized nations. The fact sheet also puts Canada on record as being in agreement with the spirit of the Kyoto Protocol to encourage the participation of developing countries in global efforts to combat climate change and promote sustainable development and reaffirms Canada's willingness to provide financial and technical assistance to developing countries to enable them to play a meaningful part in this global effort. In this context, the fact sheet briefly describes the new Canada Climate Change Development Fund which has been set up to reduce the growth of GHG emissions and support carbon sink activities in developing countries, to strengthen the capacity of developing conuntries to reduce their vulnerability to adverse effects of climate change, and to participate in global efforts to combat them

MHD flow of Powell-Eyring nanofluid over a non-linear stretching sheet with variable thickness

Directory of Open Access Journals (Sweden)

T. Hayat

Full Text Available This research explores the magnetohydrodynamic (MHD boundary layer flow of Powell-Eyring nanofluid past a non-linear stretching sheet of variable thickness. An electrically conducting fluid is considered under the characteristics of magnetic field applied transverse to the sheet. The mathematical expressions are accomplished via boundary layer access, Brownian motion and thermophoresis phenomena. The flow analysis is subjected to a recently established conditions requiring zero nanoparticles mass flux. Adequate transformations are implemented for the reduction of partial differential systems to the ordinary differential systems. Series solutions for the governing nonlinear flow of momentum, temperature and nanoparticles concentration have been executed. Physical interpretation of numerous parameters is assigned by graphical illustrations and tabular values. Moreover the numerical data of drag coefficient and local heat transfer rate are executed and discussed. It is investigated that higher wall thickness parameter results in the reduction of velocity distribution. Effects of thermophoresis parameter on temperature and concentration profiles are qualitatively similar. Both the temperature and concentration profiles are enhanced for higher values of thermophoresis parameter. Keywords: MHD, Variable thicked surface, Powell-Eyring nanofluid, Zero mass flux conditions

Survey of large-amplitude flapping motions in the midtail current sheet

Directory of Open Access Journals (Sweden)

V. A. Sergeev

2006-08-01

Full Text Available We surveyed fast current sheet crossings (flapping motions over the distance range 10–30 RE in the magnetotail covered by the Geotail spacecraft. Since the local tilts of these dynamic sheets are large and variable in these events, we compare three different methods of evaluating current sheet normals using 4-s/c Cluster data and define the success criteria for the single-spacecraft-based method (MVA to obtain the reliable results. Then, after identifying more than ~1100 fast CS crossings over a 3-year period of Geotail observations in 1997–1999, we address their parameters, spatial distribution and activity dependence. We confirm that over the entire distance covered and LT bins, fast crossings have considerable tilts in the YZ plane (from estimated MVA normals which show a preferential appearance of one (YZ kink-like mode that is responsible for these severe current sheet perturbations. Their occurrence is highly inhomogeneous; it sharply increases with radial distance and has a peak in the tail center (with some duskward shift, resembling the occurrence of the BBFs, although there is no one-to-one local correspondence between these two phenomena. The crossing durations typically spread around 1 min and decrease significantly where the high-speed flows are registered. Based on an AE index superposed epoch study, the flapping motions prefer to appear during the substorm expansion phase, although a considerable number of events without any electrojet and auroral activity were also observed. We also present statistical distributions of other parameters and briefly discuss what could be possible mechanisms to generate the flapping motions.

Real life working shift assignment problem

Science.gov (United States)

Sze, San-Nah; Kwek, Yeek-Ling; Tiong, Wei-King; Chiew, Kang-Leng

2017-07-01

This study concerns about the working shift assignment in an outlet of Supermarket X in Eastern Mall, Kuching. The working shift assignment needs to be solved at least once in every month. Current approval process of working shifts is too troublesome and time-consuming. Furthermore, the management staff cannot have an overview of manpower and working shift schedule. Thus, the aim of this study is to develop working shift assignment simulation and propose a working shift assignment solution. The main objective for this study is to fulfill manpower demand at minimum operation cost. Besides, the day off and meal break policy should be fulfilled accordingly. Demand based heuristic is proposed to assign working shift and the quality of the solution is evaluated by using the real data.

Environmental constraints on West Antarctic ice-sheet formation

Energy Technology Data Exchange (ETDEWEB)

Lindstrom, D R; MacAyeal, D R

1987-01-01

Small perturbations in Antarctic environmental conditions can culminate in the demise of the Antarctic ice sheet's western sector. This may have happened during the last interglacial period, and could recur within the next millennium due to atmospheric warming from trace gas and CO/sub 2/ increases. In this study, we investigate the importance of sea-level, accumulation rate, and ice influx from the East Antarctic ice sheet in the re-establishment of the West Antarctic ice sheet from a thin cover using a time-dependent numerical ice-shelf model. Our results show that a precursor to the West Antarctic ice sheet can form within 3000 years. Sea-level lowering caused by ice-sheet development in the Northern Hemisphere has the greatest environmental influence. Under favorable conditions, ice grounding occurs over all parts of the West Antarctic ice sheet except up-stream of Thwaites Glacier and in the Ross Sea region.

Hydrothermal growth of upright-standing ZnO sheet microcrystals

International Nuclear Information System (INIS)

Shi, Ruixia; Yang, Ping; Dong, Xiaobin; Jia, Changchao; Li, Jia

2014-01-01

Highlights: • Upright-standing ZnO sheet microcrystals were hydrothermally fabricated. • The ZnO sheets were prepared with sodium oxalate at 70 °C without any surfactant. • The preferable adsorption of oxalate anions causes the formation of ZnO sheet. • The continuous growth in six directions leads to the formation of hexagonal sheets. - Abstract: Large-scale upright-standing ZnO sheet microcrystals were fabricated on Zn substrate using sodium oxalate as structure-directing agent by a hydrothermal method at low temperature (70 °C) without any surfactant. The sheets are about 3–5 μm in dimension and 100–300 nm in thickness. The strong and narrow diffraction peaks of ZnO indicate that the sample has a good crystallinity and size. The morphology of sheet-like ZnO varied with the concentrations of sodium oxalate and reaction time. The sheet-like ZnO would transform into rod-like ones when sodium oxalate was substituted by equivalent sodium acetate. The formation of sheet-like ZnO is attributed to the preferable adsorption of oxalate anions on (0 0 0 1) face of ZnO, which inhibits the intrinsic growth of ZnO. Additionally, the continuous growth in six (0 1 −1 0) directions that have the lowest surface energy leads to the formation of hexagonal sheets

Practical implementation of Wilhelm Osbahr’s entrepreneur balance sheet theory assumptions – a case study

Directory of Open Access Journals (Sweden)

EWA ŚNIEŻEK , MICHAŁ WIATR

2015-12-01

Full Text Available The aim of this study is to present the possibilities of the practical application of Osbahr’s balance sheet theory assumptions, as one of many possible attempts to close the information gap in the financial reporting of the twenty-first century. Wilhelm Osbahr, at the beginning of the 20th century, made an attempt to solve the problem of indicating the balance sheet values (the impact of balance sheet evaluation on the balance sheet items, from the point of view of an entrepreneur or business owner, at the same time clearly emphasizing the necessity to deal with the balance sheet structure through the prism of the objectives pursued by the company. Osbahr postulated highlighting any changes occurring in the economic structure of the company and its components, which do not result directly from its operating activities, and so to present them in the position called “adjustments”. This article uses the deductive method supported by literature studies and a case study method. The authors using the case study method confirm the possibility of using the described balance sheet theory in the current financial reporting based on actual data of the company ABC Ltd. They also show that a balance sheet which is presented according to the new reporting formula discloses new quality of information for the financial reporting users.

24 CFR 221.770 - Assignment option.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Assignment option. 221.770 Section... § 221.770 Assignment option. A mortgagee holding a conditional or firm commitment issued on or before... mortgagee's approved underwriter on or before November 30, 1983) has the option to assign, transfer and...

Rapid fabricating technique for multi-layered human hepatic cell sheets by forceful contraction of the fibroblast monolayer.

Directory of Open Access Journals (Sweden)

Yusuke Sakai

Full Text Available Cell sheet engineering is attracting attention from investigators in various fields, from basic research scientists to clinicians focused on regenerative medicine. However, hepatocytes have a limited proliferation potential in vitro, and it generally takes a several days to form a sheet morphology and multi-layered sheets. We herein report our rapid and efficient technique for generating multi-layered human hepatic cell (HepaRG® cell sheets using pre-cultured fibroblast monolayers derived from human skin (TIG-118 cells as a feeder layer on a temperature-responsive culture dish. Multi-layered TIG-118/HepaRG cell sheets with a thick morphology were harvested on day 4 of culturing HepaRG cells by forceful contraction of the TIG-118 cells, and the resulting sheet could be easily handled. In addition, the human albumin and alpha 1-antitrypsin synthesis activities of TIG-118/HepaRG cells were approximately 1.2 and 1.3 times higher than those of HepaRG cells, respectively. Therefore, this technique is considered to be a promising modality for rapidly fabricating multi-layered human hepatocyte sheets from cells with limited proliferation potential, and the engineered cell sheet could be used for cell transplantation with highly specific functions.

Control of downy mildew in greenhouse-grown cucumbers using blue photoselective polyethylene sheets

International Nuclear Information System (INIS)

Reuveni, R.; Raviv, M.

1997-01-01

Six types of polyethylene sheets with or without a blue pigment, having an absorption peak at the yellow part of the spectrum (580 nm), in combination with three levels of UV-B (280 to 320 nm) absorbance, were investigated for their effects on sporangial production and colonization of Pseudoperonospora cubensis on cucumbers in growth chambers. The effect of these photoselective sheets on the epidemiology of downy mildew in greenhouse-grown cucumbers has been investigated in several locations. The addition of the blue pigment to the films resulted in a significant inhibition of colonization and sporangial production of P. cubensis, whereas filtration of the UV spectrum enhanced the colonization but had no effect on the sporangial production. The appearance of the first symptom-bearing plants was delayed under the blue covers, and consequently, a significant reduction in the disease incidence of downy mildew was recorded under all blue sheets at each corresponding level of UV-B transmittance in five different field experiments through four seasons. Regardless of the differences in disease incidence, there were no significant differences among the yields that were obtained under the various sheets, probably due to the lower photosynthetically active radiation transmissivity of the blue films. The optimal features required for a desirable commercial sheet are discussed

Job Assignments under Moral Hazard

DEFF Research Database (Denmark)

Koch, Alexander; Nafziger, Julia

Inefficient job assignments are usually explained with incomplete information about employees' abilities or contractual imperfections. We show that inefficient assignments arise even without uncertainty about the employee's ability and with complete contracts. Building on this result we provide...

EZ-ASSIGN, a program for exhaustive NMR chemical shift assignments of large proteins from complete or incomplete triple-resonance data

Energy Technology Data Exchange (ETDEWEB)

Zuiderweg, Erik R. P., E-mail: zuiderwe@umich.edu; Bagai, Ireena [The University of Michigan Medical School, Department of Biological Chemistry (United States); Rossi, Paolo [Rutgers University, Center for Integrative Proteomics Research (United States); Bertelsen, Eric B. [Arbor Communications, Inc. (United States)

2013-10-15

For several of the proteins in the BioMagResBank larger than 200 residues, 60 % or fewer of the backbone resonances were assigned. But how reliable are those assignments? In contrast to complete assignments, where it is possible to check whether every triple-resonance Generalized Spin System (GSS) is assigned once and only once, with incomplete data one should compare all possible assignments and pick the best one. But that is not feasible: For example, for 200 residues and an incomplete set of 100 GSS, there are 1.6 Multiplication-Sign 10{sup 260} possible assignments. In 'EZ-ASSIGN', the protein sequence is divided in smaller unique fragments. Combined with intelligent search approaches, an exhaustive comparison of all possible assignments is now feasible using a laptop computer. The program was tested with experimental data of a 388-residue domain of the Hsp70 chaperone protein DnaK and for a 351-residue domain of a type III secretion ATPase. EZ-ASSIGN reproduced the hand assignments. It did slightly better than the computer program PINE (Bahrami et al. in PLoS Comput Biol 5(3):e1000307, 2009) and significantly outperformed SAGA (Crippen et al. in J Biomol NMR 46:281-298, 2010), AUTOASSIGN (Zimmerman et al. in J Mol Biol 269:592-610, 1997), and IBIS (Hyberts and Wagner in J Biomol NMR 26:335-344, 2003). Next, EZ-ASSIGN was used to investigate how well NMR data of decreasing completeness can be assigned. We found that the program could confidently assign fragments in very incomplete data. Here, EZ-ASSIGN dramatically outperformed all the other assignment programs tested.

24 CFR 221.255 - Assignment option.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Assignment option. 221.255 Section... Assignment option. (a) A mortgagee holding a mortgage insured pursuant to a conditional or firm commitment issued on or before November 30, 1983 has the option to assign, transfer and deliver to the Commissioner...

Surface elevation changes of the greenland ice sheet - results from ESA'S ice sheet CCI

DEFF Research Database (Denmark)

Fredenslund Levinsen, Joanna; Khvorostovky, Kirill; Meister, Rakia

2013-01-01

In order to ensure long-term climate data records for the Greenland Ice Sheet (GIS), ESA have launched the Climate Change Initiative (CCI). This work presents the preliminary steps towards the Ice Sheet CCI's surface elevation change (SEC) derivation using radar altimeter data. In order to find...... the most optimal method, a Round Robin exercise was conducted in which the scientific community was asked to provide their best SEC estimate over the Jakobshavn Isbr drainage basin. The participants used both repeat-track (RT), overlapping footprints, and the cross-over (XO) methods, and both ICESat laser...... and Envisat radar altimeter data were used. Based on this and feedback sheets describing their methods we found that a combination of the RT and XO techniques yielded the best results. In the following, the obtained results will be presented and discussed....

Probability based hydrologic catchments of the Greenland Ice Sheet

Science.gov (United States)

Hudson, B. D.

2015-12-01

Greenland Ice Sheet melt water impacts ice sheet flow dynamics, fjord and coastal circulation, and sediment and biogeochemical fluxes. Melt water exiting the ice sheet also is a key term in its mass balance. Because of this, knowledge of the area of the ice sheet that contributes melt water to a given outlet (its hydrologic catchment) is important to many ice sheet studies and is especially critical to methods using river runoff to assess ice sheet mass balance. Yet uncertainty in delineating ice sheet hydrologic catchments is a problem that is rarely acknowledged. Ice sheet catchments are delineated as a function of both basal and surface topography. While surface topography is well known, basal topography is less certain because it is dependent on radar surveys. Here, I a present a Monte Carlo based approach to delineating ice sheet catchments that quantifies the impact of uncertain basal topography. In this scheme, over many iterations I randomly vary the ice sheet bed elevation within published error bounds (using Morlighem et al., 2014 bed and bed error datasets). For each iteration of ice sheet bed elevation, I calculate the hydraulic potentiometric surface and route water over its path of 'steepest' descent to delineate the catchment. I then use all realizations of the catchment to arrive at a probability map of all major melt water outlets in Greenland. I often find that catchment size is uncertain, with small, random perturbations in basal topography leading to large variations in catchments size. While some catchments are well defined, others can double or halve in size within published basal topography error bars. While some uncertainty will likely always remain, this work points to locations where studies of ice sheet hydrology would be the most successful, allows reinterpretation of past results, and points to where future radar surveys would be most advantageous.

On the balance of stresses in the plasma sheet.

Science.gov (United States)

Rich, F. J.; Wolf, R. A.; Vasyliunas, V. M.

1972-01-01

The stress resulting from magnetic tension on the neutral sheet must, in a steady state, be balanced by any one or a combination of (1) a pressure gradient in the direction along the axis of the tail, (2) a similar gradient of plasma flow kinetic energy, and (3) the tension resulting from a pressure anisotropy within the plasma sheet. Stress balance in the first two cases requires that the ratios h/LX and BZ/BX be of the same order of magnitude, where h is the half-thickness of the neutral sheet, LX is the length scale for variations along the axis of the tail, and BZ and BX are the magnetic field components in the plasma sheet just outside the neutral sheet. The second case requires, in addition, that the plasma flow speed within the neutral sheet be of the order of or larger than the Alfven speed outside the neutral sheet. Stress balance in the third case requires that just outside the neutral sheet the plasma pressure obey the marginal firehose stability condition.

Thermal Transport Properties of Dry Spun Carbon Nanotube Sheets

Directory of Open Access Journals (Sweden)

Heath E. Misak

2016-01-01

Full Text Available The thermal properties of carbon nanotube- (CNT- sheet were explored and compared to copper in this study. The CNT-sheet was made from dry spinning CNTs into a nonwoven sheet. This nonwoven CNT-sheet has anisotropic properties in in-plane and out-of-plane directions. The in-plane direction has much higher thermal conductivity than the out-of-plane direction. The in-plane thermal conductivity was found by thermal flash analysis, and the out-of-plane thermal conductivity was found by a hot disk method. The thermal irradiative properties were examined and compared to thermal transport theory. The CNT-sheet was heated in the vacuum and the temperature was measured with an IR Camera. The heat flux of CNT-sheet was compared to that of copper, and it was found that the CNT-sheet has significantly higher specific heat transfer properties compared to those of copper. CNT-sheet is a potential candidate to replace copper in thermal transport applications where weight is a primary concern such as in the automobile, aircraft, and space industries.

Nonparaxial Bessel and Bessel–Gauss pincers light-sheets

Energy Technology Data Exchange (ETDEWEB)

Mitri, F.G., E-mail: F.G.Mitri@ieee.org

2017-01-23

Highlights: • Bessel and Bessel–Gauss autofocusing light sheets (i.e. beams in 2D) are developed. • The light-sheets are synthesized based on the angular spectrum decomposition method. • Computations of the scattering, radiation force and torque benefit from the solutions. - Abstract: Nonparaxial optical Bessel and Bessel–Gauss pincers optical-sheets are introduced based upon the angular spectrum decomposition in plane waves. The angular spectrum function and the beam-shape coefficients are expressed by means of improper integrals computed numerically. The radiated component of the electric field is also evaluated, displaying unique features of the nonparaxial Bessel pincers light-sheets. This new type of auto-focusing light-sheets finds potential applications in the development of novel methods in optical light-sheet tweezers for particle manipulation in opto-fluidics, particle sizing and imaging. Numerical predictions for the scattering, radiation force and torque, and particle dynamics also benefit from the developed beam solution.

Nonparaxial Bessel and Bessel–Gauss pincers light-sheets

International Nuclear Information System (INIS)

Mitri, F.G.

2017-01-01

Highlights: • Bessel and Bessel–Gauss autofocusing light sheets (i.e. beams in 2D) are developed. • The light-sheets are synthesized based on the angular spectrum decomposition method. • Computations of the scattering, radiation force and torque benefit from the solutions. - Abstract: Nonparaxial optical Bessel and Bessel–Gauss pincers optical-sheets are introduced based upon the angular spectrum decomposition in plane waves. The angular spectrum function and the beam-shape coefficients are expressed by means of improper integrals computed numerically. The radiated component of the electric field is also evaluated, displaying unique features of the nonparaxial Bessel pincers light-sheets. This new type of auto-focusing light-sheets finds potential applications in the development of novel methods in optical light-sheet tweezers for particle manipulation in opto-fluidics, particle sizing and imaging. Numerical predictions for the scattering, radiation force and torque, and particle dynamics also benefit from the developed beam solution.

An algorithm for ranking assignments using reoptimization

DEFF Research Database (Denmark)

Pedersen, Christian Roed; Nielsen, Lars Relund; Andersen, Kim Allan

2008-01-01

We consider the problem of ranking assignments according to cost in the classical linear assignment problem. An algorithm partitioning the set of possible assignments, as suggested by Murty, is presented where, for each partition, the optimal assignment is calculated using a new reoptimization...... technique. Computational results for the new algorithm are presented...

48 CFR 42.602 - Assignment and location.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Assignment and location... Assignment and location. (a) A CACO may be assigned only when (1) the contractor has at least two locations..., or a full-time CACO may be assigned. In determining the location of the CACO, the responsible agency...

Bifurcation of Jovian magnetotail current sheet

Directory of Open Access Journals (Sweden)

P. L. Israelevich

2006-07-01

Full Text Available Multiple crossings of the magnetotail current sheet by a single spacecraft give the possibility to distinguish between two types of electric current density distribution: single-peaked (Harris type current layer and double-peaked (bifurcated current sheet. Magnetic field measurements in the Jovian magnetic tail by Voyager-2 reveal bifurcation of the tail current sheet. The electric current density possesses a minimum at the point of the B_x-component reversal and two maxima at the distance where the magnetic field strength reaches 50% of its value in the tail lobe.

Buckling Behavior of Substrate Supported Graphene Sheets

Directory of Open Access Journals (Sweden)

Kuijian Yang

2016-01-01

Full Text Available The buckling of graphene sheets on substrates can significantly degrade their performance in materials and devices. Therefore, a systematic investigation on the buckling behavior of monolayer graphene sheet/substrate systems is carried out in this paper by both molecular mechanics simulations and theoretical analysis. From 70 simulation cases of simple-supported graphene sheets with different sizes under uniaxial compression, two different buckling modes are investigated and revealed to be dominated by the graphene size. Especially, for graphene sheets with length larger than 3 nm and width larger than 1.1 nm, the buckling mode depends only on the length/width ratio. Besides, it is revealed that the existence of graphene substrate can increase the critical buckling stress and strain to 4.39 N/m and 1.58%, respectively, which are about 10 times those for free-standing graphene sheets. Moreover, for graphene sheets with common size (longer than 20 nm, both theoretical and simulation results show that the critical buckling stress and strain are dominated only by the adhesive interactions with substrate and independent of the graphene size. Results in this work provide valuable insight and guidelines for the design and application of graphene-derived materials and nano-electromechanical systems.

EZ-ASSIGN, a program for exhaustive NMR chemical shift assignments of large proteins from complete or incomplete triple-resonance data

International Nuclear Information System (INIS)

Zuiderweg, Erik R. P.; Bagai, Ireena; Rossi, Paolo; Bertelsen, Eric B.

2013-01-01

For several of the proteins in the BioMagResBank larger than 200 residues, 60 % or fewer of the backbone resonances were assigned. But how reliable are those assignments? In contrast to complete assignments, where it is possible to check whether every triple-resonance Generalized Spin System (GSS) is assigned once and only once, with incomplete data one should compare all possible assignments and pick the best one. But that is not feasible: For example, for 200 residues and an incomplete set of 100 GSS, there are 1.6 × 10 260 possible assignments. In “EZ-ASSIGN”, the protein sequence is divided in smaller unique fragments. Combined with intelligent search approaches, an exhaustive comparison of all possible assignments is now feasible using a laptop computer. The program was tested with experimental data of a 388-residue domain of the Hsp70 chaperone protein DnaK and for a 351-residue domain of a type III secretion ATPase. EZ-ASSIGN reproduced the hand assignments. It did slightly better than the computer program PINE (Bahrami et al. in PLoS Comput Biol 5(3):e1000307, 2009) and significantly outperformed SAGA (Crippen et al. in J Biomol NMR 46:281–298, 2010), AUTOASSIGN (Zimmerman et al. in J Mol Biol 269:592–610, 1997), and IBIS (Hyberts and Wagner in J Biomol NMR 26:335–344, 2003). Next, EZ-ASSIGN was used to investigate how well NMR data of decreasing completeness can be assigned. We found that the program could confidently assign fragments in very incomplete data. Here, EZ-ASSIGN dramatically outperformed all the other assignment programs tested

Fabrication of Carbon Nanotube Polymer Actuator Using Nanofiber Sheet

Science.gov (United States)

Kato, Hayato; Shimizu, Akikazu; Sato, Taiga; Kushida, Masahito

2017-11-01

Carbon nanotube polymer actuators were developed using composite nanofiber sheets fabricated by multi-walled carbon nanotubes(MWCNTs) and poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). Nanofiber sheets were fabricated by electrospinning method. The effect of flow rate and polymer concentration on nanofiber formation were verified for optimum condition for fabricating nanofiber sheets. We examined the properties of MWCNT/PVDF-HFP nanofiber sheets, as follows. Electrical conductivity and mechanical strength increased as the MWCNT weight ratio increased. We fabricated carbon nanotube polymer actuators using MWCNT/PVDF-HFP nanofiber sheets and succeeded in operating of our actuators.

Global ice sheet/RSL simulations using the higher-order Ice Sheet System Model.

Science.gov (United States)

Larour, E. Y.; Ivins, E. R.; Adhikari, S.; Schlegel, N.; Seroussi, H. L.; Morlighem, M.

2017-12-01

Relative sea-level rise is driven by processes that are intimately linked to the evolution ofglacial areas and ice sheets in particular. So far, most Earth System models capable of projecting theevolution of RSL on decadal to centennial time scales have relied on offline interactions between RSL andice sheets. In particular, grounding line and calving front dynamics have not been modeled in a way that istightly coupled with Elasto-Static Adjustment (ESA) and/or Glacial-Isostatic Adjustment (GIA). Here, we presenta new simulation of the entire Earth System in which both Greenland and Antarctica ice sheets are tightly coupledto an RSL model that includes both ESA and GIA at resolutions and time scales compatible with processes suchas grounding line dynamics for Antarctica ice shelves and calving front dynamics for Greenland marine-terminatingglaciers. The simulations rely on the Ice Sheet System Model (ISSM) and show the impact of higher-orderice flow dynamics and coupling feedbacks between ice flow and RSL. We quantify the exact impact of ESA andGIA inclusion on grounding line evolution for large ice shelves such as the Ronne and Ross ice shelves, as well asthe Agasea Embayment ice streams, and demonstate how offline vs online RSL simulations diverge in the long run,and the consequences for predictions of sea-level rise.This work was performed at the California Institute of Technology's Jet Propulsion Laboratory undera contract with the National Aeronautics and Space Administration's Cryosphere Science Program.

Practical implementation of Wilhelm Osbahr’s entrepreneur balance sheet theory assumptions – the case study

Directory of Open Access Journals (Sweden)

Ewa Śnieżek

2015-12-01

Full Text Available The aim of this study is to present the possibilities of the practical application of Osbahr’s balance sheet theoryassumptions, as one of many possible attempts to close the information gap in the financial reporting of thetwenty-first century. Wilhelm Osbahr, at the beginning of the 20th century, made an attempt to solve the problemof indicating the balance sheet values (the impact of balance sheet evaluation on the balance sheet items,from the point of view of an entrepreneur or business owner, at the same time clearly emphasizing the necessityto deal with the balance sheet structure through the prism of the objectives pursued by the company. Osbahrpostulated highlighting any changes occurring in the economic structure of the company and its components,which do not result directly from its operating activities, and so to present them in the position called “adjustments”.This article uses the deductive method supported by literature studies and a case study method. Theauthors using the case study method confirm the possibility of using the described balance sheet theory in thecurrent financial reporting based on actual data of the company ABC Ltd. They also show that a balance sheetwhich is presented according to the new reporting formula discloses new quality of information for the financialreporting users.

Spatially Localized Particle Energization by Landau Damping in Current Sheets

Science.gov (United States)

Howes, G. G.; Klein, K. G.; McCubbin, A. J.

2017-12-01

Understanding the mechanisms of particle energization through the removal of energy from turbulent fluctuations in heliospheric plasmas is a grand challenge problem in heliophysics. Under the weakly collisional conditions typical of heliospheric plasma, kinetic mechanisms must be responsible for this energization, but the nature of those mechanisms remains elusive. In recent years, the spatial localization of plasma heating near current sheets in the solar wind and numerical simulations has gained much attention. Here we show, using the innovative and new field-particle correlation technique, that the spatially localized particle energization occurring in a nonlinear gyrokinetic simulation has the velocity space signature of Landau damping, suggesting that this well-known collisionless damping mechanism indeed actively leads to spatially localized heating in the vicinity of current sheets.

Transplantation of periodontal ligament cell sheets expressing human β-defensin-3 promotes anti-inflammation in a canine model of periodontitis

Science.gov (United States)

Zhu, Minwen; Miao, Bo; Zhu, Jianhua; Wang, Haiyan; Zhou, Zengtong

2017-01-01

Periodontitis is a chronic oral inflammatory disease caused by microorganisms. Human β-defensin-3 (HBD-3) is an endogenous antimicrobial peptide that inhibits a broad spectrum of microorganisms. Cell sheet technology has been widely applied in tissue and organ reconstructions. In the current study, it was aimed to investigate the anti-inflammatory effect of periodontal tissue engineered by HBD-3 gene-modified periodontal ligament cell (PDLC) sheets, and to identify a suitable method of promoting the regeneration of periodontal tissues. Western blot analysis and antimicrobial tests were used to confirm the expression of HBD-3. The effect of the cell sheets on anti-inflammatory activity and bone remodeling in a dog model of periodontitis was demonstrated by immunohistochemistry. The results demonstrated that the transfected PDLCs stably expressed HBD-3. Periodontal pathogens were susceptible to the antimicrobial activity of the cell sheets. In addition, the cell sheets relieved the bone resorption caused by inflammation in the in vivo model. HBD-3 may potentially be applied in the treatment of periodontitis and may function as osteogenic promoter via its anti-inflammatory effect. PMID:28944821

Coupling of climate models and ice sheet models by surface mass balance gradients: application to the Greenland Ice Sheet

Directory of Open Access Journals (Sweden)

M. M. Helsen

2012-03-01

Full Text Available It is notoriously difficult to couple surface mass balance (SMB results from climate models to the changing geometry of an ice sheet model. This problem is traditionally avoided by using only accumulation from a climate model, and parameterizing the meltwater run-off as a function of temperature, which is often related to surface elevation (H_s. In this study, we propose a new strategy to calculate SMB, to allow a direct adjustment of SMB to a change in ice sheet topography and/or a change in climate forcing. This method is based on elevational gradients in the SMB field as computed by a regional climate model. Separate linear relations are derived for ablation and accumulation, using pairs of H_s and SMB within a minimum search radius. The continuously adjusting SMB forcing is consistent with climate model forcing fields, also for initially non-glaciated areas in the peripheral areas of an ice sheet. When applied to an asynchronous coupled ice sheet – climate model setup, this method circumvents traditional temperature lapse rate assumptions. Here we apply it to the Greenland Ice Sheet (GrIS. Experiments using both steady-state forcing and glacial-interglacial forcing result in realistic ice sheet reconstructions.

Complete assignments of NMR data and assessment of trypanocidal activity of new eremantholide C derivatives

Energy Technology Data Exchange (ETDEWEB)

Saude-Guimaraes, Denia Antunes, E-mail: saude@ef.ufop.br, E-mail: saudeguima@gmail.com [Universidade Federal de Ouro Preto (UFOP), MG (Brazil); Raslan, Delio S.; Chiari, Egler; Oliveira, Alaide B. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

2014-12-15

Chemical transformations of eremantholide C (1), a sesquiterpene lactone that was isolated from Lychnophora trichocarpha Spreng. led to five new derivatives: 1’,2’- epoxyeremantholide C (2), 5-n-propylamine-4,5-dihydro-1’,2’-epoxyeremantholide C (3), 5-n-propylammonium-4,5-dihydro-1’,2’-epoxyeremantholide C chloride (4), 5-n-propylammonium-4,5-dihydroeremantolide C chloride (5) and 16-O-ethyleremantholide C (6). The structures of all these derivatives were assigned on the basis of IR, MS, {sup 1}H and {sup 13}C NMR data by 1D and 2D techniques. Eremantholide C and the derivatives 2, 4 and 5 were evaluated against trypomastigotes Y and CL strains of Trypanosoma cruzi. Eremantholide C completely inhibited the growth of both the parasites strains while all derivatives were partially active against the CL strain and inactive against the Y strain. (author)

Joining of Aluminium Alloy Sheets by Rectangular Mechanical Clinching

International Nuclear Information System (INIS)

Abe, Y.; Mori, K.; Kato, T.

2011-01-01

A mechanical clinching has the advantage of low running costs. However, the joint strength is not high. To improve the maximum load of the joined sheets by a mechanical clinching, square and rectangular mechanical clinching were introduced. In the mechanical clinching, the two sheets are mechanically joined by forming an interlock between the lower and upper sheets by the punch and die. The joined length with the interlock was increased by the rectangular punch and die. The deforming behaviours of the sheets in the mechanical clinching were investigated, and then the interlock in the sheets had distribution in the circumference of the projection. Although the interlocks were formed in both projection side and diagonal, the interlock in the diagonal was smaller because of the long contact length between the lower sheet and the die cavity surface. The maximum load of the joined sheets by the rectangular mechanical clinching was two times larger than the load by the round mechanical clinching.

The properties of bioengineered chondrocyte sheets for cartilage regeneration

Directory of Open Access Journals (Sweden)

Ota Naoshi

2009-03-01

Full Text Available Abstract Background Although the clinical results of autologous chondrocyte implantation for articular cartilage defects have recently improved as a result of advanced techniques based on tissue engineering procedures, problems with cell handling and scaffold imperfections remain to be solved. A new cell-sheet technique has been developed, and is potentially able to overcome these obstacles. Chondrocyte sheets applicable to cartilage regeneration can be prepared with this cell-sheet technique using temperature-responsive culture dishes. However, for clinical application, it is necessary to evaluate the characteristics of the cells in these sheets and to identify their similarities to naive cartilage. Results The expression of SOX 9, collagen type 2, 27, integrin α10, and fibronectin genes in triple-layered chondrocyte sheets was significantly increased in comparison to those in conventional monolayer culture and in a single chondrocyte sheet, implying a nature similar to ordinary cartilage. In addition, immunohistochemistry demonstrated that collagen type II, fibronectin, and integrin α10 were present in the triple-layered chondrocyte sheets. Conclusion The results of this study indicate that these chondrocyte sheets with a consistent cartilaginous phenotype and adhesive properties may lead to a new strategy for cartilage regeneration.

Crystal Plasticity Finite Element Analysis of Loading-Unloading Behaviour in Magnesium Alloy Sheet

International Nuclear Information System (INIS)

Hama, Takayuki; Fujimoto, Hitoshi; Takuda, Hirohiko

2010-01-01

Magnesium alloy sheets exhibit strong inelastic response during unloading. In this study crystal plasticity finite element analysis of loading-unloading behaviour during uniaxial tension in a rolled magnesium alloy sheet was carried out, and the mechanism of this inelastic response was examined in detail in terms of macroscopic and mesoscopic deformations. The unloading behaviour obtained by the simulation was in good agreement with the experiment in terms of variation with stress of instantaneous tangent modulus during unloading. Variations of activities of each family of slip systems during the deformation showed that the activation of basal slip systems is the largest during unloading, and the slip direction during unloading is opposite from during loading. These results indicated that one of the factors of the inelastic behaviour during unloading is the fact that the basal slip systems are easily activated during unloading because of their low strengths.

Homework Assignments to Enhance Student Engagement in Secondary Education

Science.gov (United States)

Buijs, Maartje; Admiraal, Wilfried

2013-01-01

Secondary school teachers often complain that their students show a disengaged attitude in class. Students do not prepare for lessons, they show a passive attitude towards classroom activities and they have a limited awareness of their own learning process. Based on a pilot study, four homework assignments were designed, implemented, and evaluated…

Exogenous spatial attention influences figure-ground assignment.

Science.gov (United States)

Vecera, Shaun P; Flevaris, Anastasia V; Filapek, Joseph C

2004-01-01

In a hierarchical stage account of vision, figure-ground assignment is thought to be completed before the operation of focal spatial attention. Results of previous studies have supported this account by showing that unpredictive, exogenous spatial precues do not influence figure-ground assignment, although voluntary attention can influence figure-ground assignment. However, in these studies, attention was not summoned directly to a region in a figure-ground display. In three experiments, we addressed the relationship between figure-ground assignment and visuospatial attention. In Experiment 1, we replicated the finding that exogenous precues do not influence figure-ground assignment when they direct attention outside of a figure-ground stimulus. In Experiment 2, we demonstrated that exogenous attention can influence figure-ground assignment if it is directed to one of the regions in a figure-ground stimulus. In Experiment 3, we demonstrated that exogenous attention can influence figure-ground assignment in displays that contain a Gestalt figure-ground cue; this result suggests that figure-ground processes are not entirely completed prior to the operation of focal spatial attention. Exogenous spatial attention acts as a cue for figure-ground assignment and can affect the outcome of figure-ground processes.

Design and numerical analysis of an SMA mesh-based self-folding sheet

International Nuclear Information System (INIS)

Peraza-Hernandez, Edwin A; Hartl, Darren J; Malak Jr, Richard J

2013-01-01

Origami engineering, which is the practice of creating useful three-dimensional structures through folding and fold-like operations applied to initially two-dimensional entities, has the potential to impact several areas of design and manufacturing. In some instances, however, it may be impractical to apply external manipulations to produce the desired folds (e.g., as in remote applications such as space systems). In such cases, self-folding capabilities are valuable. A self-folding material or material system is one that can perform folding operations without manipulations from external forces. This work considers a concept for a self-folding material system. The system extends the ‘programmable matter’ concept and consists of an active, self-morphing sheet composed of two meshes of thermally actuated shape memory alloy (SMA) wire separated by a compliant passive layer. The geometric and power input parameters of the self-folding sheet are optimized to achieve the tightest local fold possible subject to stress and temperature constraints. The sheet folding performance considering folds at different angles relative to the orientation of the wire mesh is also analyzed. The optimization results show that a relatively low elastomer thickness is preferable to generate the tightest fold possible. The results also show that the self-folding sheet does not require large power inputs to achieve an optimal folding performance. It was shown that the self-folding sheet is capable of creating similar quality folds at different orientations. (paper)

Fatigue characteristics of dual-phase steel sheets

Energy Technology Data Exchange (ETDEWEB)

Onn, Irwan Herman; Ahmad, Norhayati; Tamin, Mohd Nasir [Universiti Teknologi Malaysia, Skudai (Malaysia)

2015-01-15

Fatigue characteristics of dual-phase steel sheets, commonly used in automobile body construction were established. For this purpose, a series of fatigue tests, each at constant stress amplitude were conducted on 1.2 mm-thick, dual-phase DP600 steel sheet specimens with two different load ratios of minimum-to-maximum stress, R = 0.1 and -1. The resulting fatigue behavior is expressed in terms of fatigue strength-life (S-N) curves. Fatigue behavior of the steel sheets in the high-cycle fatigue region can be represented by Basquin's equation with coefficient and exponent value of 921.2 and 0.093, respectively. An endurance limit of 255 MPa is observed. In addition, fatigue strengths of the dual-phase steel sheets display lower magnitude than their bulk counterparts. Effect of mean stress on fatigue behavior of the steel sheets is well predicted by Walker's model. Exponential calibration factor is introduced to the models by SWT, Goodman and Morrow with comparable prediction to the Walker's model.

Dynamics of a radially expanding liquid sheet: Experiments

Science.gov (United States)

Majumdar, Nayanika; Tirumkudulu, Mahesh

2017-11-01

A recent theory predicts that sinuous waves generated at the center of a radially expanding liquid sheet grow spatially even in absence of a surrounding gas phase. Unlike flat liquid sheets, the thickness of a radially expanding liquid sheet varies inversely with distance from the center of the sheet. To test the predictions of the theory, experiments were carried out on a horizontal, radially expanding liquid sheet formed by collision of a single jet on a solid impactor. The latter was placed on a speaker-vibrator with controlled amplitude and frequency. The growth of sinuous waves was determined by measuring the wave surface inclination angle using reflected laser light under both atmospheric and sub-atmospheric pressure conditions. It is shown that the measured growth rate matches with the predictions of the theory over a large range of Weber numbers for both pressure conditions suggesting that the thinning of the liquid sheet plays a dominant role in setting the growth rate of sinuous waves with minimal influence of the surrounding gas phase on its dynamics. IIT Bombay.

Balance of the West Antarctic Ice Sheet

Science.gov (United States)

2002-01-01

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

Spina Bifida: General Information. Fact Sheet Number 12 = La Espina Bifida: Informacion General. Fact Sheet Number 12.

Science.gov (United States)

National Information Center for Children and Youth with Disabilities, Washington, DC.

This fact sheet offers definitions of the three types of spina bifida, outlines their incidence, describes characteristics of individuals with spina bifida, and reviews educational implications. The fact sheet emphasizes that school programs should be flexible to accommodate these students' special needs and frequent absences, that children with…

Ice Sheets & Ice Cores

DEFF Research Database (Denmark)

Mikkelsen, Troels Bøgeholm

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

Microstructure evolution of a dissimilar junction interface between an Al sheet and a Ni-coated Cu sheet joined by magnetic pulse welding

Energy Technology Data Exchange (ETDEWEB)

Itoi, Takaomi, E-mail: itoi@faculty.chiba-u.jp [Department of Mechanical Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Mohamad, Azizan Bin; Suzuki, Ryo [Department of Mechanical Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Okagawa, Keigo [Department of Electrical and Electronics Engineering, Tokyo Metropolitan College of Industrial Technology, 1-10-40 Higashi ohi, Shinagawa-ku, Tokyo 140-0011 (Japan)

2016-08-15

An Al sheet and a Ni-coated Cu sheet were lap joined by using magnetic pulse welding (MPW). Tensile tests were performed on the joined sheets, and a good lap joint was achieved at a discharge energy of > 0.9 kJ. The weld interface exhibited a wavy morphology and an intermediate layer along the weld interface. Microstructure observations of the intermediate layer revealed that the Ni coating region consisted of a Ni–Al binary amorphous alloy and that the Al sheet region contained very fine Al nanograins. Ni fragments indicative of unmelted residual Ni from the coating were also observed in parts of the intermediate layer. Formation of these features can be attributed to localize melting and a subsequent high rate cooling of molten Al and Ni confined to the interface during the MPW process. In the absence of an oxide film, atomic-scale bonding was also achieved between the intermediate layer and the sheet surfaces after the collision. MPW utilises impact energy, which affects the sheet surfaces. From the obtained results, good lap joint is attributed to an increased contact area, the anchor effect, work hardening, the absence of an oxide film, and suppressed formation of intermetallic compounds at the interface. - Highlights: •Good lap joint of an Al sheet and a Ni-coated Cu sheet was achieved by using magnetic pulse welding. •A Ni–Al binary amorphous alloy was formed as an intermediate layer at weld interface. •Atomic-scale bonding was achieved between the intermediate layer and the sheet surfaces.

Strong correlation in acene sheets from the active-space variational two-electron reduced density matrix method: effects of symmetry and size.

Science.gov (United States)

Pelzer, Kenley; Greenman, Loren; Gidofalvi, Gergely; Mazziotti, David A

2011-06-09

Polyaromatic hydrocarbons (PAHs) are a class of organic molecules with importance in several branches of science, including medicine, combustion chemistry, and materials science. The delocalized π-orbital systems in PAHs require highly accurate electronic structure methods to capture strong electron correlation. Treating correlation in PAHs has been challenging because (i) traditional wave function methods for strong correlation have not been applicable since they scale exponentially in the number of strongly correlated orbitals, and (ii) alternative methods such as the density-matrix renormalization group and variational two-electron reduced density matrix (2-RDM) methods have not been applied beyond linear acene chains. In this paper we extend the earlier results from active-space variational 2-RDM theory [Gidofalvi, G.; Mazziotti, D. A. J. Chem. Phys. 2008, 129, 134108] to the more general two-dimensional arrangement of rings--acene sheets--to study the relationship between geometry and electron correlation in PAHs. The acene-sheet calculations, if performed with conventional wave function methods, would require wave function expansions with as many as 1.5 × 10(17) configuration state functions. To measure electron correlation, we employ several RDM-based metrics: (i) natural-orbital occupation numbers, (ii) the 1-RDM von Neumann entropy, (iii) the correlation energy per carbon atom, and (iv) the squared Frobenius norm of the cumulant 2-RDM. The results confirm a trend of increasing polyradical character with increasing molecular size previously observed in linear PAHs and reveal a corresponding trend in two-dimensional (arch-shaped) PAHs. Furthermore, in PAHs of similar size they show significant variations in correlation with geometry. PAHs with the strictly linear geometry (chains) exhibit more electron correlation than PAHs with nonlinear geometries (sheets).

Evoked Feelings, Assigned Meanings and Constructed Knowledge Based on Mistakes

Directory of Open Access Journals (Sweden)

Luciane Guimarães Batistella Bianchini

2017-09-01

Full Text Available By means of Piaget's critical clinical method, the study investigated the meanings assigned to mistakes by four students in different activities and interactive situations. The research also analyzed the results of using self-regulatory situations in understanding mistakes initially committed by the students. Data collection instruments consisted of games, video recordings, diaries and interviews. Following intervention, the students were able to recognize their competence, establish positive interactions within the group, and avoid viewing mistakes as obstacles to learning. We concluded that the meanings assigned to mistakes depend on certain variables, among them feelings nurtured by the individuals about themselves, the other, and the object of knowledge.

Synthesis of nanometre-thick MoO3 sheets

Science.gov (United States)

Kalantar-Zadeh, Kourosh; Tang, Jianshi; Wang, Minsheng; Wang, Kang L.; Shailos, Alexandros; Galatsis, Kosmas; Kojima, Robert; Strong, Veronica; Lech, Andrew; Wlodarski, Wojtek; Kaner, Richard B.

2010-03-01

The formation of MoO3 sheets of nanoscale thickness is described. They are made from several fundamental sheets of orthorhombic α-MoO3, which can be processed in large quantities via a low cost synthesis route that combines thermal evaporation and mechanical exfoliation. These fundamental sheets consist of double-layers of linked distorted MoO6 octahedra. Atomic force microscopy (AFM) measurements show that the minimum resolvable thickness of these sheets is 1.4 nm which is equivalent to the thickness of two double-layers within one unit cell of the α-MoO3 crystal.

Fact Sheets on Pesticides in Schools.

Science.gov (United States)

National Coalition against the Misuse of Pesticides, Washington, DC.

This document consists of a collection of fact sheets about the use of pesticides in schools and how to reduce it. The sheets are: (1) "Alternatives to Using Pesticides in Schools: What Is Integrated Pest Management?"; (2) "Health Effects of 48 Commonly Used Pesticides in Schools"; (3) "The Schooling of State Pesticide…

Single clay sheets inside electrospun polymer nanofibers

Science.gov (United States)

Sun, Zhaohui

2005-03-01

Nanofibers were prepared from polymer solution with clay sheets by electrospinning. Plasma etching, as a well controlled process, was used to supply electrically excited gas molecules from a glow discharge. To reveal the structure and arrangement of clay layers in the polymer matrix, plasma etching was used to remove the polymer by controlled gasification to expose the clay sheets due to the difference in reactivity. The shape, flexibility, and orientation of clay sheets were studied by transmission and scanning electron microscopy. Additional quantitative information on size distribution and degree of exfoliation of clay sheets were obtained by analyzing electron micrograph of sample after plasma etching. Samples in various forms including fiber, film and bulk, were thinned by plasma etching. Morphology and dispersion of inorganic fillers were studied by electron microscopy.

Complex world-sheets from N=2 strings

International Nuclear Information System (INIS)

Barbon, J.L.F.

1996-01-01

We study some properties of target space strings constructed from (2,1) heterotic strings. We argue that world-sheet complexification is a general property of the bosonic sector of such target world-sheets. We give a target space interpretation of this fact and relate it to the non-gaussian nature of free string field theory. We provide several one-loop calculations supporting the stringy construction of critical world-sheets in terms of (2,1) models. Using finite-temperature boundary conditions in the underlying (2,1) string we obtain non-chiral target space spin structures, and point out some of the problems arising for chiral spin structures, such as the heterotic world-sheet. To this end, we study the torus partition function of the corresponding asymmetric orbifold of the (2,1) string. (orig.)

Motion and shape of snowplough sheets in coaxial accelerators

International Nuclear Information System (INIS)

Tsagas, N.F.; Mair, G.L.R.; Prinn, A.E.

1978-01-01

A long coaxial accelerator is filled with helium at initial gas pressure between 0.2 and 4 Torr. When connected to a large capacitor at < - 10 kV a discharge is started at one end; the central electrode has negative polarity. The velocity of the plasma sheet, the snowplough, and its shape have been derived from streak photographs for terminal currents between about 100 and 300 kA. The motion of the sheet has been analysed by balancing the electromagnetic driving force against the inertia of the mass of the gas swept up by a plane sheet taken to be impenetrable to gas atoms. The calculated positions and average sheet velocities, which involve simplifying assumptions, have been found to be in good agreement with observations at different positions and pressures. Also the shape of the sheet has been derived by allowing for the sheet's curvature in the linear momentum equation while net radial motions causing variations in profile have, at first, been excluded. The calculated shape of the sheet is very nearly that photographically observed. The axial velocity of a sheet element is evaluated under the assumption that the plasma is azimuthally uniform, free of spikes and that the vessel's wall does not affect the shape. (author)

Corrosion Behavior of Brazed Zinc-Coated Structured Sheet Metal

Directory of Open Access Journals (Sweden)

A. Nikitin

2017-01-01

Full Text Available Arc brazing has, in comparison to arc welding, the advantage of less heat input while joining galvanized sheet metals. The evaporation of zinc is reduced in the areas adjacent to the joint and improved corrosion protection is achieved. In the automotive industry, lightweight design is a key technology against the background of the weight and environment protection. Structured sheet metals have higher stiffness compared to typical automobile sheet metals and therefore they can play an important role in lightweight structures. In the present paper, three arc brazing variants of galvanized structured sheet metals were validated in terms of the corrosion behavior. The standard gas metal arc brazing, the pulsed arc brazing, and the cold metal transfer (CMT® in combination with a pulsed cycle were investigated. In experimental climate change tests, the influence of the brazing processes on the corrosion behavior of galvanized structured sheet metals was investigated. After that, the corrosion behavior of brazed structured and flat sheet metals was compared. Because of the selected lap joint, the valuation of damage between sheet metals was conducted. The pulsed CMT brazing has been derived from the results as the best brazing method for the joining process of galvanized structured sheet metals.

76 FR 71968 - Proposed Agency Information Collection Activities; Comment Request

Science.gov (United States)

2011-11-21

... balance sheets in the volatile period following the collapse of Lehman Brothers in the fall of 2008 likely... assign OMB control numbers to collection of information requests and requirements conducted or sponsored... currently valid OMB control number. DATES: Comments must be submitted on or before December 12, 2011...

N-Isopropylacrylamide-co-glycidylmethacrylate as a Thermoresponsive Substrate for Corneal Endothelial Cell Sheet Engineering

Directory of Open Access Journals (Sweden)

Bernadette K. Madathil

2014-01-01

Full Text Available Endothelial keratoplasty is a recent shift in the surgical treatment of corneal endothelial dystrophies, where the dysfunctional endothelium is replaced whilst retaining the unaffected corneal layers. To overcome the limitation of donor corneal shortage, alternative use of tissue engineered constructs is being researched. Tissue constructs with intact extracellular matrix are generated using stimuli responsive polymers. In this study we evaluated the feasibility of using the thermoresponsive poly(N-isopropylacrylamide-co-glycidylmethacrylate polymer as a culture surface to harvest viable corneal endothelial cell sheets. Incubation below the lower critical solution temperature of the polymer allowed the detachment of the intact endothelial cell sheet. Phase contrast and scanning electron microscopy revealed the intact architecture, cobble stone morphology, and cell-to-cell contact in the retrieved cell sheet. Strong extracellular matrix deposition was also observed. The RT-PCR analysis confirmed functionally active endothelial cells in the cell sheet as evidenced by the positive expression of aquaporin 1, collagen IV, Na+-K+ ATPase, and FLK-1. Na+-K+ ATPase protein expression was also visualized by immunofluorescence staining. These results suggest that the in-house developed thermoresponsive culture dish is a suitable substrate for the generation of intact corneal endothelial cell sheet towards transplantation for endothelial keratoplasty.

Orientation and Morphology Effects in Rapid Silicon Sheet Solidification

Science.gov (United States)

Ciszek, T. F.

1984-01-01

Radial growth anisotropies and equilibrium forms of point nucleated, dislocation free silicon sheets spreading horizontally on the free surface of a silicon melt were measured for (100), (110), (111), and (112) sheet planes. The growth process was recorded. Qualitative Wulff surface free energy polar plots were deduced from the equilibrium shapes for each sheet plane. Predicted geometries for the tip shape of unidirectional, dislocation free, horizontally grown sheets growing in various directions within the planes were analyzed. Polycrystalline sheets and dendrite propagation were analyzed. For dendrites, growth rates on the order of 2.5 m/min and growth rate anisotropies of 25 are measured.

WebAssign: Assessing Your Students' Understanding Continuously

Science.gov (United States)

Risley, John S.

1999-11-01

Motivating students to learn is a constant challenge for faculty. Technology can play a significant role. One such solution is WebAssign — a web-based homework system that offers new teaching and learning opportunities for educators and their students. WebAssign delivers, collects, grades, and records customized homework assignments over the Internet. Students get immediate feedback with credit and instructors can implement "Just-in-Time" teaching. In this talk, I will describe how assignments can be generated with different numerical values for each question, giving each student a unique problem to solve. This feature encourages independent thinking with the benefit of collaborative learning. Example assignments taken from textbook questions and intellectually engaging Java applet simulations will be shown. Studies and first-hand experience on the educational impact of using WebAssign will also be discussed.

47 CFR 32.101 - Structure of the balance sheet accounts.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Structure of the balance sheet accounts. 32.101... UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.101 Structure of the balance sheet accounts. The Balance Sheet accounts shall be maintained as follows...

Molding cork sheets to complex shapes

Science.gov (United States)

Sharpe, M. H.; Simpson, W. G.; Walker, H. M.

1977-01-01

Partially cured cork sheet is easily formed to complex shapes and then final-cured. Temperature and pressure levels required for process depend upon resin system used and final density and strength desired. Sheet can be bonded to surface during final cure, or can be first-formed in mold and bonded to surface in separate step.

Whooping Cough (Pertussis) - Fact Sheet for Parents

Science.gov (United States)

... months 4 through 6 years Fact Sheet for Parents Color [2 pages] Español: Tosferina (pertussis) The best ... according to the recommended schedule. Fact Sheets for Parents Diseases and the Vaccines that Prevent Them Chickenpox ...

The storm time central plasma sheet

Directory of Open Access Journals (Sweden)

R. Schödel

2002-11-01

Full Text Available The plasma sheet plays a key role during magnetic storms because it is the bottleneck through which large amounts of magnetic flux that have been eroded from the dayside magnetopause have to be returned to the dayside magnetosphere. Using about five years of Geotail data we studied the average properties of the near- and midtail central plasma sheet (CPS in the 10–30 RE range during magnetic storms. The earthward flux transport rate is greatly enhanced during the storm main phase, but shows a significant earthward decrease. Hence, since the magnetic flux cannot be circulated at a sufficient rate, this leads to an average dipolarization of the central plasma sheet. An increase of the specific entropy of the CPS ion population by a factor of about two during the storm main phase provides evidence for nonadiabatic heating processes. The direction of flux transport during the main phase is consistent with the possible formation of a near-Earth neutral line beyond ~20 RE.Key words. Magnetospheric physics (plasma convection; plasma sheet; storms and substorms

New directions in the science and technology of advanced sheet explosive formulations and the key energetic materials used in the processing of sheet explosives: Emerging trends.

Science.gov (United States)

Talawar, M B; Jangid, S K; Nath, T; Sinha, R K; Asthana, S N

2015-12-30

This review presents the work carried out by the international community in the area of sheet explosive formulations and its applications in various systems. The sheet explosive is also named as PBXs and is a composite material in which solid explosive particles like RDX, HMX or PETN are dispersed in a polymeric matrix, forms a flexible material that can be rolled/cut into sheet form which can be applied to any complex contour. The designed sheet explosive must possess characteristic properties such as flexible, cuttable, water proof, easily initiable, and safe handling. The sheet explosives are being used for protecting tanks (ERA), light combat vehicle and futuristic infantry carrier vehicle from different attacking war heads etc. Besides, sheet explosives find wide applications in demolition of bridges, ships, cutting and metal cladding. This review also covers the aspects such as risks and hazard analysis during the processing of sheet explosive formulations, effect of ageing on sheet explosives, detection and analysis of sheet explosive ingredients and the R&D efforts of Indian researchers in the development of sheet explosive formulations. To the best of our knowledge, there has been no review article published in the literature in the area of sheet explosives. Copyright © 2015 Elsevier B.V. All rights reserved.

Electrochemical depth profiling of multilayer metallic structures: An aluminum brazing sheet

International Nuclear Information System (INIS)

Afshar, F. Norouzi; Ambat, R.; Kwakernaak, C.; Wit, J.H.W. de; Mol, J.M.C.; Terryn, H.

2012-01-01

Highlights: ► Localized electrochemical cell and glow discharge optical emission spectrometry were used. ► An electrochemical depth profile of an aluminum brazing sheet was obtained. ► The electrochemical responses were correlated to the microstructural features. - Abstract: Combinatory localized electrochemical cell and glow discharge optical emission spectrometry (GDOES) measurements were performed to obtain a thorough in depth electrochemical characterization of an aluminum brazing sheet. By defining electrochemical criteria i.e. breakdown potential, corrosion potential, cathodic and anodic reactivities, and tracking their changes as a function of depth, the evolution of electrochemical responses through out the material thickness were analyzed and correlated to the corresponding microstructural features. Polarization curves in 1 wt% NaCl solution at pH 2.8 were obtained at different depths from the surface using controlled sputtering in a glow discharge optical emission spectrometer as a sample preparation technique. The anodic and cathodic reactivity of the top surface areas were significantly higher than that of the bulk, thus indicating these areas to be more susceptible to localized attack. Consistent with this, optical microscopy and scanning electron microscope analysis revealed a relatively high density of fine intermetallic and silicon particles at these areas. The corrosion mechanism of the top layers was identified to be intergranular and pitting corrosion, while lower sensitivity to these localized attacks were detected toward the brazing sheet core. The results highlight the successful application of the electrochemical depth profiling approach in prediction of the corrosion behavior of the aluminum brazing sheet and the importance of the electrochemical activity of the outer 10 μm in controlling the corrosion performance of the aluminum brazing sheet.

Transplantation of periodontal ligament cell sheets expressing human β‑defensin‑3 promotes anti‑inflammation in a canine model of periodontitis.

Science.gov (United States)

Zhu, Minwen; Miao, Bo; Zhu, Jianhua; Wang, Haiyan; Zhou, Zengtong

2017-11-01

Periodontitis is a chronic oral inflammatory disease caused by microorganisms. Human β‑defensin‑3 (HBD‑3) is an endogenous antimicrobial peptide that inhibits a broad spectrum of microorganisms. Cell sheet technology has been widely applied in tissue and organ reconstructions. In the current study, it was aimed to investigate the anti‑inflammatory effect of periodontal tissue engineered by HBD‑3 gene‑modified periodontal ligament cell (PDLC) sheets, and to identify a suitable method of promoting the regeneration of periodontal tissues. Western blot analysis and antimicrobial tests were used to confirm the expression of HBD‑3. The effect of the cell sheets on anti‑inflammatory activity and bone remodeling in a dog model of periodontitis was demonstrated by immunohistochemistry. The results demonstrated that the transfected PDLCs stably expressed HBD‑3. Periodontal pathogens were susceptible to the antimicrobial activity of the cell sheets. In addition, the cell sheets relieved the bone resorption caused by inflammation in the in vivo model. HBD‑3 may potentially be applied in the treatment of periodontitis and may function as osteogenic promoter via its anti‑inflammatory effect.

The Cryosphere Model Comparison Tool (CmCt): Ice Sheet Model Validation and Comparison Tool for Greenland and Antarctica

Science.gov (United States)

Simon, E.; Nowicki, S.; Neumann, T.; Tyahla, L.; Saba, J. L.; Guerber, J. R.; Bonin, J. A.; DiMarzio, J. P.

2017-12-01

The Cryosphere model Comparison tool (CmCt) is a web based ice sheet model validation tool that is being developed by NASA to facilitate direct comparison between observational data and various ice sheet models. The CmCt allows the user to take advantage of several decades worth of observations from Greenland and Antarctica. Currently, the CmCt can be used to compare ice sheet models provided by the user with remotely sensed satellite data from ICESat (Ice, Cloud, and land Elevation Satellite) laser altimetry, GRACE (Gravity Recovery and Climate Experiment) satellite, and radar altimetry (ERS-1, ERS-2, and Envisat). One or more models can be uploaded through the CmCt website and compared with observational data, or compared to each other or other models. The CmCt calculates statistics on the differences between the model and observations, and other quantitative and qualitative metrics, which can be used to evaluate the different model simulations against the observations. The qualitative metrics consist of a range of visual outputs and the quantitative metrics consist of several whole-ice-sheet scalar values that can be used to assign an overall score to a particular simulation. The comparison results from CmCt are useful in quantifying improvements within a specific model (or within a class of models) as a result of differences in model dynamics (e.g., shallow vs. higher-order dynamics approximations), model physics (e.g., representations of ice sheet rheological or basal processes), or model resolution (mesh resolution and/or changes in the spatial resolution of input datasets). The framework and metrics could also be used for use as a model-to-model intercomparison tool, simply by swapping outputs from another model as the observational datasets. Future versions of the tool will include comparisons with other datasets that are of interest to the modeling community, such as ice velocity, ice thickness, and surface mass balance.

Australian Government Balance Sheet Management

OpenAIRE

Wilson Au-Yeung; Jason McDonald; Amanda Sayegh

2006-01-01

Since almost eliminating net debt, the Australian Government%u2019s attention has turned to the financing of broader balance sheet liabilities, such as public sector superannuation. Australia will be developing a significant financial asset portfolio in the %u2018Future Fund%u2019 to smooth the financing of expenses through time. This raises the significant policy question of how best to manage the government balance sheet to reduce risk. This paper provides a framework for optimal balance sh...

Energy information sheets, July 1998

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-07-01

The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the public. The Energy Information Sheets was developed to provide general information on various aspects of fuel production, prices, consumption, and capability. Additional information on related subject matter can be found in other Energy Information Administration (EIA) publications as referenced at the end of each sheet.

Energy information sheets, September 1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-09-01

The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the public. The Energy Information Sheets was developed to provide general information on various aspects of fuel production, prices, consumption, and capability. Additional information on related subject matter can be found in other Energy Information Administration (EIA) publications as referenced at the end of each sheet.

Anesthesia Fact Sheet

Science.gov (United States)

... Education About NIGMS NIGMS Home > Science Education > Anesthesia Anesthesia Tagline (Optional) Middle/Main Content Area En español ... Version (464 KB) Other Fact Sheets What is anesthesia? Anesthesia is a medical treatment that prevents patients ...

Ice flow Modelling of the Greenland Ice Sheet

DEFF Research Database (Denmark)

Nielsen, Lisbeth Tangaa

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

Forced tearing of ductile and brittle thin sheets.

Science.gov (United States)

Tallinen, T; Mahadevan, L

2011-12-09

Tearing a thin sheet by forcing a rigid object through it leads to complex crack morphologies; a single oscillatory crack arises when a tool is driven laterally through a brittle sheet, while two diverging cracks and a series of concertinalike folds forms when a tool is forced laterally through a ductile sheet. On the other hand, forcing an object perpendicularly through the sheet leads to radial petallike tears in both ductile and brittle materials. To understand these different regimes we use a combination of experiments, simulations, and simple theories. In particular, we describe the transition from brittle oscillatory tearing via a single crack to ductile concertina tearing with two tears by deriving laws that describe the crack paths and wavelength of the concertina folds and provide a simple phase diagram for the morphologies in terms of the material properties of the sheet and the relative size of the tool.

Self-inhibiting growth of the Greenland Ice Sheet

DEFF Research Database (Denmark)

Langen, Peter Lang; Solgaard, Anne Munck; Hvidberg, Christine Schøtt

2012-01-01

The build-up of the Greenland Ice Sheet (GrIS) from ice-free conditions is studied in an ice sheet model (ISM) driven by fields from an atmospheric general circulation model (GCM) to demonstrate the importance of coupling between the two components. Experiments where the two are coupled off-line...... are augmented by one where an intermediate ice sheet configuration is coupled back to the GCM. Forcing the ISM with GCM fields corresponding to the ice-free state leads to extensive regrowth which, however, is halted when the intermediate recoupling step is included. This inhibition of further growth is due...... to a Föhn effect of moist air parcels being lifted over the intermediate ice sheet and arriving in the low-lying Greenland interior with high temperatures. This demonstrates that two-way coupling between the atmosphere and the ice sheet is essential for understanding the dynamics and that large scale...

Antibubbles and fine cylindrical sheets of air

KAUST Repository

Beilharz, D.

2015-08-14

Drops impacting at low velocities onto a pool surface can stretch out thin hemispherical sheets of air between the drop and the pool. These air sheets can remain intact until they reach submicron thicknesses, at which point they rupture to form a myriad of microbubbles. By impacting a higher-viscosity drop onto a lower-viscosity pool, we have explored new geometries of such air films. In this way we are able to maintain stable air layers which can wrap around the entire drop to form repeatable antibubbles, i.e. spherical air layers bounded by inner and outer liquid masses. Furthermore, for the most viscous drops they enter the pool trailing a viscous thread reaching all the way to the pinch-off nozzle. The air sheet can also wrap around this thread and remain stable over an extended period of time to form a cylindrical air sheet. We study the parameter regime where these structures appear and their subsequent breakup. The stability of these thin cylindrical air sheets is inconsistent with inviscid stability theory, suggesting stabilization by lubrication forces within the submicron air layer. We use interferometry to measure the air-layer thickness versus depth along the cylindrical air sheet and around the drop. The air film is thickest above the equator of the drop, but thinner below the drop and up along the air cylinder. Based on microbubble volumes, the thickness of the cylindrical air layer becomes less than 100 nm before it ruptures.

Antibubbles and fine cylindrical sheets of air

KAUST Repository

Beilharz, D.; Guyon, A.; Li, E.  Q.; Thoraval, M.-J.; Thoroddsen, Sigurdur T

2015-01-01

Drops impacting at low velocities onto a pool surface can stretch out thin hemispherical sheets of air between the drop and the pool. These air sheets can remain intact until they reach submicron thicknesses, at which point they rupture to form a myriad of microbubbles. By impacting a higher-viscosity drop onto a lower-viscosity pool, we have explored new geometries of such air films. In this way we are able to maintain stable air layers which can wrap around the entire drop to form repeatable antibubbles, i.e. spherical air layers bounded by inner and outer liquid masses. Furthermore, for the most viscous drops they enter the pool trailing a viscous thread reaching all the way to the pinch-off nozzle. The air sheet can also wrap around this thread and remain stable over an extended period of time to form a cylindrical air sheet. We study the parameter regime where these structures appear and their subsequent breakup. The stability of these thin cylindrical air sheets is inconsistent with inviscid stability theory, suggesting stabilization by lubrication forces within the submicron air layer. We use interferometry to measure the air-layer thickness versus depth along the cylindrical air sheet and around the drop. The air film is thickest above the equator of the drop, but thinner below the drop and up along the air cylinder. Based on microbubble volumes, the thickness of the cylindrical air layer becomes less than 100 nm before it ruptures.

Nonparaxial Bessel and Bessel-Gauss pincers light-sheets

Science.gov (United States)

Mitri, F. G.

2017-01-01

Nonparaxial optical Bessel and Bessel-Gauss pincers optical-sheets are introduced based upon the angular spectrum decomposition in plane waves. The angular spectrum function and the beam-shape coefficients are expressed by means of improper integrals computed numerically. The radiated component of the electric field is also evaluated, displaying unique features of the nonparaxial Bessel pincers light-sheets. This new type of auto-focusing light-sheets finds potential applications in the development of novel methods in optical light-sheet tweezers for particle manipulation in opto-fluidics, particle sizing and imaging. Numerical predictions for the scattering, radiation force and torque, and particle dynamics also benefit from the developed beam solution.

Ice Sheet Roughness Estimation Based on Impulse Responses Acquired in the Global Ice Sheet Mapping Orbiter Mission

Science.gov (United States)

Niamsuwan, N.; Johnson, J. T.; Jezek, K. C.; Gogineni, P.

2008-12-01

The Global Ice Sheet Mapping Orbiter (GISMO) mission was developed to address scientific needs to understand the polar ice subsurface structure. This NASA Instrument Incubator Program project is a collaboration between Ohio State University, the University of Kansas, Vexcel Corporation and NASA. The GISMO design utilizes an interferometric SAR (InSAR) strategy in which ice sheet reflected signals received by a dual-antenna system are used to produce an interference pattern. The resulting interferogram can be used to filter out surface clutter so as to reveal the signals scattered from the base of the ice sheet. These signals are further processed to produce 3D-images representing basal topography of the ice sheet. In the past three years, the GISMO airborne field campaigns that have been conducted provide a set of useful data for studying geophysical properties of the Greenland ice sheet. While topography information can be obtained using interferometric SAR processing techniques, ice sheet roughness statistics can also be derived by a relatively simple procedure that involves analyzing power levels and the shape of the radar impulse response waveforms. An electromagnetic scattering model describing GISMO impulse responses has previously been proposed and validated. This model suggested that rms-heights and correlation lengths of the upper surface profile can be determined from the peak power and the decay rate of the pulse return waveform, respectively. This presentation will demonstrate a procedure for estimating the roughness of ice surfaces by fitting the GISMO impulse response model to retrieved waveforms from selected GISMO flights. Furthermore, an extension of this procedure to estimate the scattering coefficient of the glacier bed will be addressed as well. Planned future applications involving the classification of glacier bed conditions based on the derived scattering coefficients will also be described.

Complete 1H and 13C NMR assignments and anti fungal activity of two 8-hydroxy flavonoids in mixture

International Nuclear Information System (INIS)

Johann, Susana; Smania Junior, Artur; Branco, Alexsandro

2007-01-01

A mixture of the two new flavonols 8-hydroxy-3, 4', 5, 6, 7-pentamethoxyflavone (1) and 8-hydroxy-3, 3', 4', 5, 6, 7-hexamethoxyflavone (2) was isolated from a commercial sample of Citrus aurantifolia. An array of one- ( 1 H NMR, { 1 H} -13 C NMR, and APT -13 C NMR) and two-dimensional NMR techniques (COSY, NOESY, HMQC and HMBC) was used to achieve the structural elucidation and the complete 1 H and 13 C chemical shift assignments of these natural compounds. In addition, the antifungal activity of these compounds against phytopathogenic and human pathogenic fungi was investigated. (author)

Observations of the Formation, Development, and Structure of a Current Sheet in an Eruptive Solar Flare

Energy Technology Data Exchange (ETDEWEB)

Seaton, Daniel B.; Darnel, Jonathan M. [Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, CO 80305 (United States); Bartz, Allison E., E-mail: daniel.seaton@noaa.gov [Department of Physics, Grinnell College, Grinnell, IA 50112 (United States)

2017-02-01

We present Atmospheric Imaging Assembly observations of a structure we interpret as a current sheet associated with an X4.9 flare and coronal mass ejection that occurred on 2014 February 25 in NOAA Active Region 11990. We characterize the properties of the current sheet, finding that the sheet remains on the order of a few thousand kilometers thick for much of the duration of the event and that its temperature generally ranged between 8 and 10 MK. We also note the presence of other phenomena believed to be associated with magnetic reconnection in current sheets, including supra-arcade downflows and shrinking loops. We estimate that the rate of reconnection during the event was M{sub A} ≈ 0.004–0.007, a value consistent with model predictions. We conclude with a discussion of the implications of this event for reconnection-based eruption models.

Protein unfolding versus β-sheet separation in spider silk nanocrystals

International Nuclear Information System (INIS)

Alam, Parvez

2014-01-01

In this communication a mechanism for spider silk strain hardening is proposed. Shear failure of β-sheet nanocrystals is the first failure mode that gives rise to the creation of smaller nanocrystals, which are of higher strength and stiffness. β-sheet unfolding requires more energy than nanocrystal separation in a shear mode of failure. As a result, unfolding occurs after the nanocrystals separate in shear. β-sheet unfolding yields a secondary strain hardening effect once the β-sheet conformation is geometrically stable and acts like a unidirectional fibre in a fibre reinforced composite. The mechanism suggested herein is based on molecular dynamics calculations of residual inter-β-sheet separation strengths against residual intra-β-sheet unfolding strengths. (paper)

Cerebral Palsy: General Information. Fact Sheet Number 2 = La Paralisis Cerebral: Informacion General. Fact Sheet Number 18.

Science.gov (United States)

Interstate Research Associates, McLean, VA.

This fact sheet on cerebral palsy is offered in both English and Spanish. First, it provides a definition and considers various causes (e.g., an insufficient amount of oxygen reaching the fetal or newborn brain). The fact sheet then offers incidence figures and explains characteristics of the three main types of cerebral palsy: spastic, athetoid,…

An expert system for process planning of sheet metal parts produced

Indian Academy of Sciences (India)

Process planning of sheet metal part is an important activity in the design of compound die. Traditional methods of carrying out this task are manual, tedious, time-consuming, error-prone and experiencebased. This paper describes the research work involved in the development of an expert system for process planning of ...

Solving the rectangular assignment problem and applications

NARCIS (Netherlands)

Bijsterbosch, J.; Volgenant, A.

2010-01-01

The rectangular assignment problem is a generalization of the linear assignment problem (LAP): one wants to assign a number of persons to a smaller number of jobs, minimizing the total corresponding costs. Applications are, e.g., in the fields of object recognition and scheduling. Further, we show

7 CFR 900.106 - Assignment of mediator.

Science.gov (United States)

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Assignment of mediator. 900.106 Section 900.106 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing... Assignment of mediator. The Director of the Division shall assign a mediator, from the group designated by...

Film sheet cassette

International Nuclear Information System (INIS)

1981-01-01

A novel film sheet cassette is described for handling CAT photographic films under daylight conditions and facilitating their imaging. A detailed description of the design and operation of the cassette is given together with appropriate illustrations. The resulting cassette is a low-cost unit which is easily constructed and yet provides a sure light-tight seal for the interior contents of the cassette. The individual resilient fingers on the light-trap permit the ready removal of the slide plate for taking pictures. The stippled, non-electrostatic surface of the pressure plate ensures an air layer and free slidability of the film for removal and withdrawal of the film sheet. The advantage of the daylight system is that a darkroom need not be used for inserting and removing the film in and out of the cassette resulting in a considerable time saving. (U.K.)

An Adaptive Test Sheet Generation Mechanism Using Genetic Algorithm

Directory of Open Access Journals (Sweden)

Huan-Yu Lin

2012-01-01

Full Text Available For test-sheet composition systems, it is important to adaptively compose test sheets with diverse conceptual scopes, discrimination and difficulty degrees to meet various assessment requirements during real learning situations. Computation time and item exposure rate also influence performance and item bank security. Therefore, this study proposes an Adaptive Test Sheet Generation (ATSG mechanism, where a Candidate Item Selection Strategy adaptively determines candidate test items and conceptual granularities according to desired conceptual scopes, and an Aggregate Objective Function applies Genetic Algorithm (GA to figure out the approximate solution of mixed integer programming problem for the test-sheet composition. Experimental results show that the ATSG mechanism can efficiently, precisely generate test sheets to meet the various assessment requirements than existing ones. Furthermore, according to experimental finding, Fractal Time Series approach can be applied to analyze the self-similarity characteristics of GA’s fitness scores for improving the quality of the test-sheet composition in the near future.

Simulations of the Scandinavian ice sheet and its subsurface conditions

International Nuclear Information System (INIS)

Boulton, G.S.; Caban, P.; Hulton, N.

1999-12-01

An ice sheet model has been applied to an approximate flow line through the area of the Fennoscandian ice sheet. The modelled ice sheet fluctuations have been matched with stratigraphic evidence of Weichselian ice sheet fluctuation in order to simulate ice sheet attributes through time along the flowline. The model predicts extensive melting at the base of the ice sheet. This output has been used as an input to a simplified model of hydrogeology along the southern flank of the ice sheet so as to reconstruct patterns of subglacial groundwater flow. The output from the model is also used to estimate patterns of subglacial stress and strain. Results suggest that large scale subglacial groundwater catchment are formed which were quite different in extent from modern catchment; that fossil subglacial groundwaters should be found at sampling depths; and much fracturing in shallow bedrock in Sweden could be glacially generated

Simulations of the Scandinavian ice sheet and its subsurface conditions

Energy Technology Data Exchange (ETDEWEB)

Boulton, G.S.; Caban, P.; Hulton, N. [Edinburgh Univ. (United Kingdom). Dept of Geology and Geophysics

1999-12-01

An ice sheet model has been applied to an approximate flow line through the area of the Fennoscandian ice sheet. The modelled ice sheet fluctuations have been matched with stratigraphic evidence of Weichselian ice sheet fluctuation in order to simulate ice sheet attributes through time along the flowline. The model predicts extensive melting at the base of the ice sheet. This output has been used as an input to a simplified model of hydrogeology along the southern flank of the ice sheet so as to reconstruct patterns of subglacial groundwater flow. The output from the model is also used to estimate patterns of subglacial stress and strain. Results suggest that large scale subglacial groundwater catchment are formed which were quite differentin extent from modern catchment; that fossil subglacial groundwaters should be found at sampling depths; and much fracturing in shallow bedrock in Sweden could be glacially generated.

Synthesis, characterization and optical properties of sheet-like ZnO

International Nuclear Information System (INIS)

Liu, Changzhen; Meng, Dawei; Wu, Xiuling; Wang, Yongqian; Yu, Xiaohong; Zhang, Zhengjie; Liu, Xiaoyang

2011-01-01

Highlights: → Sheet-like ZnO with regular hexagon shape was synthesized with a two-step method. → Sheet-like ZnO predecessor was synthesized at low temperature in open system. → The diameter and thickness of ZnO sheet can be controlled conveniently. → This low-cost and environmentally benign approach is controllable and reproducible. → Sheet-like ZnO may have potential application in optical and electrical devices. -- Abstract: Sheet-like ZnO with regular hexagon shape and uniform diameter has been successfully synthesized through a two-step method without any metal catalyst. First, the sheet-like ZnO precursor was synthesized in a weak alkaline carbamide environment with stirring in a constant temperature water-bath by the homogeneous precipitation method, then sheet-like ZnO was obtained by calcining at 600 o C for 2 h. The structures and optical properties of sheet-like ZnO have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL) and UV-vis-NIR spectrophotometer. The results reveal that the product is highly crystalline with hexagonal wurtzite phase and has appearance of hexagon at (0 0 0 1) plane. The HRTEM images confirm that the individual sheet-like ZnO is single crystal. The PL spectrum exhibits a narrow ultraviolet emission at 397 nm and a broad visible emission centering at 502 nm. The band gap of sheet-like ZnO is about 3.15 eV.

Comparison of Corrosion Behavior of Electrochemically Deposited Nano-Cobalt-Coated Ni Sheet

Directory of Open Access Journals (Sweden)

Nasser Al-Aqeeli

2013-01-01

Full Text Available Corrosion behavior of nano-coblat-coated Ni sheet was compared with pure Ni and 20% Fe-Ni alloy sheet using potentiodynamic polarization and linear polarization technique in 0.1 M NaCl solution at room temperature. Results showed that corrosion resistance properties of nano-Co-coated Ni sheet were almost same as that of pure Ni sheet, however corrosion resistance of 20% Fe-Ni sheet was decreased significantly. Pitting potential of 20% Fe-Ni sheet was subsequently decreased as compared to pure Ni sheet as well as nano-cobalt-coated Ni sheet. SEM/EDS analysis of the corroded surfaces showed that both pure Ni and nano-coblat-coated Ni sheet did not show any appreciable corrosion however significant corrosion was observed in the case of 20% Fe-Ni sheet.

My Favorite Assignment.

Science.gov (United States)

ABCA Bulletin, 1983

1983-01-01

Describes three assignments for enticing business communication students to undertake library research: an analysis of a Fortune 500 company, a career choice report, and a report on an organization that offers potential employment. (AEA)

14 CFR Section 3 - Chart of Balance Sheet Accounts

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Chart of Balance Sheet Accounts Section 3 Section 3 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... Balance Sheet Classifications Section 3 Chart of Balance Sheet Accounts [See footnotes at end of table...

17 CFR 229.1001 - (Item 1001) Summary term sheet.

Science.gov (United States)

2010-04-01

... sheet that is written in plain English. The summary term sheet must briefly describe in bullet point format the most material terms of the proposed transaction. The summary term sheet must provide security... transaction. The bullet points must cross-reference a more detailed discussion contained in the disclosure...

Theoretical Predictions of Freestanding Honeycomb Sheets of Cadmium Chalcogenides

Energy Technology Data Exchange (ETDEWEB)

Zhou, Jia [ORNL; Huang, Jingsong [ORNL; Sumpter, Bobby G [ORNL; Kent, Paul R [ORNL; Xie, Yu [ORNL; Terrones Maldonado, Humberto [ORNL; Smith, Sean C [ORNL

2014-01-01

Two-dimensional (2D) nanocrystals of CdX (X = S, Se, Te) typically grown by colloidal synthesis are coated with organic ligands. Recent experimental work on ZnSe showed that the organic ligands can be removed at elevated temperature, giving a freestanding 2D sheet of ZnSe. In this theoretical work, freestanding single- to few-layer sheets of CdX, each possessing a pseudo honeycomb lattice, are considered by cutting along all possible lattice planes of the bulk zinc blende (ZB) and wurtzite (WZ) phases. Using density functional theory, we have systematically studied their geometric structures, energetics, and electronic properties. A strong surface distortion is found to occur for all of the layered sheets, and yet all of the pseudo honeycomb lattices are preserved, giving unique types of surface corrugations and different electronic properties. The energetics, in combination with phonon mode calculations and molecular dynamics simulations, indicate that the syntheses of these freestanding 2D sheets could be selective, with the single- to few-layer WZ110, WZ100, and ZB110 sheets being favored. Through the GW approximation, it is found that all single-layer sheets have large band gaps falling into the ultraviolet range, while thicker sheets in general have reduced band gaps in the visible and ultraviolet range. On the basis of the present work and the experimental studies on freestanding double-layer sheets of ZnSe, we envision that the freestanding 2D layered sheets of CdX predicted herein are potential synthesis targets, which may offer tunable band gaps depending on their structural features including surface corrugations, stacking motifs, and number of layers.

NTPR Fact Sheets

Science.gov (United States)

History Documents US Underground Nuclear Test History Reports NTPR Radiation Exposure Reports Enewetak Atoll Cleanup Documents TRAC About Who We Are Our Values History Locations Our Leadership Director Support Center Contact Us FAQ Sheet Links Success Stories Contracts Business Opportunities Current

Single-Molecule Light-Sheet Imaging of Suspended T Cells.

Science.gov (United States)

Ponjavic, Aleks; McColl, James; Carr, Alexander R; Santos, Ana Mafalda; Kulenkampff, Klara; Lippert, Anna; Davis, Simon J; Klenerman, David; Lee, Steven F

2018-05-08

Adaptive immune responses are initiated by triggering of the T cell receptor. Single-molecule imaging based on total internal reflection fluorescence microscopy at coverslip/basal cell interfaces is commonly used to study this process. These experiments have suggested, unexpectedly, that the diffusional behavior and organization of signaling proteins and receptors may be constrained before activation. However, it is unclear to what extent the molecular behavior and cell state is affected by the imaging conditions, i.e., by the presence of a supporting surface. In this study, we implemented single-molecule light-sheet microscopy, which enables single receptors to be directly visualized at any plane in a cell to study protein dynamics and organization in live, resting T cells. The light sheet enabled the acquisition of high-quality single-molecule fluorescence images that were comparable to those of total internal reflection fluorescence microscopy. By comparing the apical and basal surfaces of surface-contacting T cells using single-molecule light-sheet microscopy, we found that most coated-glass surfaces and supported lipid bilayers profoundly affected the diffusion of membrane proteins (T cell receptor and CD45) and that all the surfaces induced calcium influx to various degrees. Our results suggest that, when studying resting T cells, surfaces are best avoided, which we achieve here by suspending cells in agarose. Copyright © 2018. Published by Elsevier Inc.

The social balance sheet 2004

OpenAIRE

Ph. Delhez; P. Heuse

2005-01-01

Each year, in the 4th quarter’s Economic Review, the National Bank examines the provisional results of the social balance sheets. As all the social balance sheets are not yet available for 2004, the study is based on a limited population of enterprises, compiled according to the principle of a constant sample. This population is made up of 38,530 enterprises employing around 1,331,000 workers in 2004. The main results of the analysis, in terms of employment, working hours, labour cost and tra...

Analysis of Financial Position Based on the Balance Sheet

OpenAIRE

Spineanu-Georgescu Luciana

2011-01-01

Analysis of financial position based on the balance sheet is mainly aimed at assessing the extent to which financial structure chosen by the firm, namely, financial resources, covering the needs reflected in the balance sheet financed. This is done through an analysis known as horizontal analysis balance sheet financial imbalances.

Sense and readability: participant information sheets for research studies.

Science.gov (United States)

Ennis, Liam; Wykes, Til

2016-02-01

Informed consent in research is partly achieved through the use of information sheets. There is a perception however that these information sheets are long and complex. The recommended reading level for patient information is grade 6, or 11-12 years old. To investigate whether the readability of participant information sheets has changed over time, whether particular study characteristics are related to poorer readability and whether readability and other study characteristics are related to successful study recruitment. Method: We obtained 522 information sheets from the UK National Institute for Health Research Clinical Research Network: Mental Health portfolio database and study principal investigators. Readability was assessed with the Flesch reading index and the Grade level test. Information sheets increased in length over the study period. The mean grade level across all information sheets was 9.8, or 15-16 years old. A high level of patient involvement was associated with more recruitment success and studies involving pharmaceutical or device interventions were the least successful. The complexity of information sheets had little bearing on successful recruitment. Information sheets are far more complex than the recommended reading level of grade 6 for patient information. The disparity may be exacerbated by an increasing focus on legal content. Researchers would benefit from clear guidance from ethics committees on writing succinctly and accessibly and how to balance the competing legal issues with the ability of participants to understand what a study entails. © The Royal College of Psychiatrists 2016.

Advanced friction modeling for sheet metal forming

NARCIS (Netherlands)

Hol, J.; Cid Alfaro, M.V.; de Rooij, Matthias B.; Meinders, Vincent T.

2012-01-01

The Coulomb friction model is frequently used for sheet metal forming simulations. This model incorporates a constant coefficient of friction and does not take the influence of important parameters such as contact pressure or deformation of the sheet material into account. This article presents a

Advanced friction modeling in sheet metal forming

NARCIS (Netherlands)

Hol, J.; Cid Alfaro, M.V.; Meinders, Vincent T.; Huetink, Han

2011-01-01

The Coulomb friction model is frequently used for sheet metal forming simulations. This model incorporates a constant coefficient of friction and does not take the influence of important parameters such as contact pressure or deformation of the sheet material into account. This article presents a

VISL: A Virtual Ice Sheet Laboratory For Outreach and K-12 Education

Science.gov (United States)

Cheng, D. L. C.; Halkides, D. J.; Larour, E. Y.; Moore, J.; Dunn, S.; Perez, G.

2015-12-01

We present an update on our developing Virtual Ice Sheet Laboratory (VISL). Geared to K-12 classrooms and the general public, VISL's main goal is to improve climate literacy, especially in regards to the crucial role of the polar ice sheets in Earth's climate and sea level. VISL will allow users to perform guided experiments using the Ice Sheet System Model (ISSM), a state-of-the-art ice flow model developed at NASA's Jet Propulsion Laboratory and UC Irvine that simulates the near-term evolution of the ice sheets on Greenland and Antarctica. VISL users will access ISSM via a graphical interface that can be launched from a web browser on a computer, tablet or smart phone. Users select climate conditions and run time by moving graphic sliders then watch how a given region evolves in time under those conditions. Lesson plans will include conceptual background, instructions for table top experiments related to the concepts addressed in a given lesson, and a guide for performing model experiments and interpreting their results. Activities with different degrees of complexity will aim for consistency with NGSS Physical Science criteria for different grade bands (K-2, 3-5, 6-8, and 9-12), although they will not be labeled as such to encourage a broad user base. Activities will emphasize the development of physical intuition and critical thinking skills, understanding conceptual and computational models, as well as observation recording, concept articulation, hypothesis formulation and testing, and mathematical analysis. At our present phase of development, we seek input from the greater science education and outreach communities regarding VISL's planned content, as well as additional features and topic areas that educators and students would find useful.

Glaciers and Ice Sheets As Analog Environments of Potentially Habitable Icy Worlds

Directory of Open Access Journals (Sweden)

Eva Garcia-Lopez

2017-07-01

Full Text Available Icy worlds in the solar system and beyond have attracted a remarkable attention as possible habitats for life. The current consideration about whether life exists beyond Earth is based on our knowledge of life in terrestrial cold environments. On Earth, glaciers and ice sheets have been considered uninhabited for a long time as they seemed too hostile to harbor life. However, these environments are unique biomes dominated by microbial communities which maintain active biochemical routes. Thanks to techniques such as microscopy and more recently DNA sequencing methods, a great biodiversity of prokaryote and eukaryote microorganisms have been discovered. These microorganisms are adapted to a harsh environment, in which the most extreme features are the lack of liquid water, extremely cold temperatures, high solar radiation and nutrient shortage. Here we compare the environmental characteristics of icy worlds, and the environmental characteristics of terrestrial glaciers and ice sheets in order to address some interesting questions: (i which are the characteristics of habitability known for the frozen worlds, and which could be compatible with life, (ii what are the environmental characteristics of terrestrial glaciers and ice sheets that can be life-limiting, (iii What are the microbial communities of prokaryotic and eukaryotic microorganisms that can live in them, and (iv taking into account these observations, could any of these planets or satellites meet the conditions of habitability? In this review, the icy worlds are considered from the point of view of astrobiological exploration. With the aim of determining whether icy worlds could be potentially habitable, they have been compared with the environmental features of glaciers and ice sheets on Earth. We also reviewed some field and laboratory investigations about microorganisms that live in analog environments of icy worlds, where they are not only viable but also metabolically active.

Supraglacial bacterial community structures vary across the Greenland ice sheet

DEFF Research Database (Denmark)

Cameron, Karen A.; Stibal, Marek; Zarsky, Jakub D.

2016-01-01

The composition and spatial variability of microbial communities that reside within the extensive (>200 000 km(2)) biologically active area encompassing the Greenland ice sheet (GrIS) is hypothesized to be variable. We examined bacterial communities from cryoconite debris and surface ice across...... the GrIS, using sequence analysis and quantitative PCR of 16S rRNA genes from co-extracted DNA and RNA. Communities were found to differ across the ice sheet, with 82.8% of the total calculated variation attributed to spatial distribution on a scale of tens of kilometers separation. Amplicons related...... to Sphingobacteriaceae, Pseudanabaenaceae and WPS-2 accounted for the greatest portion of calculated dissimilarities. The bacterial communities of ice and cryoconite were moderately similar (global R = 0.360, P = 0.002) and the sampled surface type (ice versus cryoconite) did not contribute heavily towards community...

Properties of Rolled AZ31 Magnesium Alloy Sheet Fabricated by Continuous Variable Cross-Section Direct Extrusion

Science.gov (United States)

Liu, Yang; Li, Feng; Li, Xue Wen; Shi, Wen Yong

2018-03-01

Rolling is currently a widely used method for manufacturing and processing high-performance magnesium alloy sheets and has received widespread attention in recent years. Here, we combined continuous variable cross-section direct extrusion (CVCDE) and rolling processes. The microstructure and mechanical properties of the resulting sheets rolled at different temperatures from CVCDE extrudate were investigated by optical microscopy, scanning electron microscope, transmission electron microscopy and electron backscatter diffraction. The results showed that a fine-grained microstructure was present with an average grain size of 3.62 μm in sheets rolled from CVCDE extrudate at 623 K. Dynamic recrystallization and a large strain were induced by the multi-pass rolling, which resulted in grain refinement. In the 573-673 K range, the yield strength, tensile strength and elongation initially increased and then declined as the CVCDE temperature increased. The above results provide an important scientific basis of processing, manufacturing and the active control on microstructure and property for high-performance magnesium alloy sheet.

Managing voluntary turnover through challenging assignments

NARCIS (Netherlands)

Preenen, P.T.Y.; de Pater, I.E.; van Vianen, A.E.M.; Keijzer, L.

2011-01-01

This study examines employees’ challenging assignments as manageable means to reduce turnover intentions, job search behaviors, and voluntary turnover. Results indicate that challenging assignments are negatively related to turnover intentions and job search behaviors and that these relationships

Managing voluntary turnover through challenging assignments

NARCIS (Netherlands)

Preenen, P.T.Y.; Pater, I.E. de; Vianen, A.E.M. van; Keijzer, L.

2011-01-01

This study examines employees' challenging assignments as manageable means to reduce turnover intentions, job search behaviors, and voluntary turnover. Results indicate that challenging assignments are negatively related to turnover intentions and job search behaviors and that these relationships

Production (information sheets)

NARCIS (Netherlands)

2007-01-01

Documentation sheets: Geo energy 2 Integrated System Approach Petroleum Production (ISAPP) The value of smartness 4 Reservoir permeability estimation from production data 6 Coupled modeling for reservoir application 8 Toward an integrated near-wellbore model 10 TNO conceptual framework for "E&P

Ebselen Preserves Tissue-Engineered Cell Sheets and their Stem Cells in Hypothermic Conditions.

Science.gov (United States)

Katori, Ryosuke; Hayashi, Ryuhei; Kobayashi, Yuki; Kobayashi, Eiji; Nishida, Kohji

2016-12-14

Clinical trials have been performed using autologous tissue-engineered epithelial cell sheets for corneal regenerative medicine. To improve stem cell-based therapy for convenient clinical practice, new techniques are required for preserving reconstructed tissues and their stem/progenitor cells until they are ready for use. In the present study, we screened potential preservative agents and developed a novel medium for preserving the cell sheets and their stem/progenitor cells; the effects were evaluated with a luciferase-based viability assay. Nrf2 activators, specifically ebselen, could maintain high ATP levels during preservation. Ebselen also showed a strong influence on maintenance of the viability, morphology, and stem cell function of the cell sheets preserved under hypothermia by protecting them from reactive oxygen species-induced damage. Furthermore, ebselen drastically improved the preservation performance of human cornea tissues and their stem cells. Therefore, ebselen shows good potential as a useful preservation agent in regenerative medicine as well as in cornea transplantation.

Ion and electron Kappa distribution functions in the plasma sheet.

Science.gov (United States)

Moya, P. S.; Stepanova, M. V.; Espinoza, C.; Antonova, E. E.; Valdivia, J. A.

2017-12-01

We present a study of ion and electron flux spectra in the Earth's plasma sheet using kappa distribution functions. Satellite data from the THEMIS mission were collected for thousands of crossings through the plasma sheet, between 7 and 35 Re and during the years 2008-2009. The events were separated according to the geomagnetic activity at the time. Our results show the distribution of the kappa index and characteristic energies across the plasma sheet and its evolution with distance to Earth for quiet times and for the substorm expansion and recovery phases. For the ions, it is observed that the kappa values tend to decrease outwards and that this effect is more significant in the dusk sector, where the smallest values are found for distances beyond 15 Re. The main effect of the substorms appears as an enhancement of this behavior. The electrons show a much more homogeneous distribution in quiet times, with a mild tendency for larger kappa values at larger distances. During substorms, the kappa values tend to equalize and appear very homogenous during expansion. However, they exhibit a significant increase in the dusk sector during the recovery substorm phase. Finally, we observe that the characteristic energy of the particles during substorms increases and concentrate at distances less than 15 Re.

Basic design of on-line analyzer for sheet paper using X-ray fluorescence (XRF) technique

International Nuclear Information System (INIS)

Rony Djokorayono; Ahmad Suntoro; Ikhsan Shobari; Usep Setia Gunawan

2016-01-01

Basic design of on-line analyzer for sheet paper using X-ray fluorescence technique has been carried out. Compared with sampling technique, this X-ray fluorescence technique has some advantages in term of analysis accuracy and time. The design activities performed including the establishment of design requirements, functional requirements, technical requirements, technical specification, detection sub-system design, data acquisition sub-system design, and operator computer console design. This program will use silicon drift or CdTe X-ray detector to detect X-ray fluorescence emitted by elements in sheet paper due to X-ray interaction of a X-ray source, 55 Fe (Ferro-55).This basic design of on-line analyzer for sheet paper using X-ray fluorescence technique should be followed up with the development of detailed design, prototype construction, and field testing. (author)

Evolution of the MHD sheet pinch

International Nuclear Information System (INIS)

Matthaeus, W.H.; Montgomery, D.

1979-01-01

A magnetohydrodynamic (MHD) problem of recurrent interest for both astrophysical and laboratory plasmas is the evolution of the unstable sheet pinch, a current sheet across which a dc magnetic field reverses sign. The evolution of such a sheet pinch is followed with a spectral-method, incompressible, two-dimensional, MHD turbulence code. Spectral diagnostics are employed, as are contour plots of vector potential (magnetic field lines), electric current density, and velocity stream function (velocity streamlines). The nonlinear effect which seems most important is seen to be current filamentation: the concentration of the current density onto sets of small measure near a mgnetic X point. A great deal of turbulence is apparent in the current distribution, which, for high Reynolds numbers, requires large spatial grids (greater than or equal to (64) 2 ). 11 figures, 1 table

Dipole-sheet multipole magnets for accelerators

International Nuclear Information System (INIS)

Walstrom, P.L.

1993-01-01

The dipole-sheet formalism can be used to describe both cylindrical current-sheet multipole magnets and cylindrical-bore magnets made up of permanent magnet blocks. For current sheets, the formalism provides a natural way of finding a finite set of turns that approximate a continuous distribution. The formalism is especially useful In accelerator applications where large-bore, short, high-field-quality magnets that are dominated by fringe fields are needed. A further advantage of the approach is that in systems with either open or cylindrically symmetric magnetic boundaries, analytical expressions for the three-dimensional fields that are suitable for rapid numerical evaluation can be derived. This development is described in some detail. Also, recent developments in higher-order particle-beam optics codes based on the formalism are described briefly

Influence of temperature fluctuations on equilibrium ice sheet volume

Science.gov (United States)

Bøgeholm Mikkelsen, Troels; Grinsted, Aslak; Ditlevsen, Peter

2018-01-01

Forecasting the future sea level relies on accurate modeling of the response of the Greenland and Antarctic ice sheets to changing temperatures. The surface mass balance (SMB) of the Greenland Ice Sheet (GrIS) has a nonlinear response to warming. Cold and warm anomalies of equal size do not cancel out and it is therefore important to consider the effect of interannual fluctuations in temperature. We find that the steady-state volume of an ice sheet is biased toward larger size if interannual temperature fluctuations are not taken into account in numerical modeling of the ice sheet. We illustrate this in a simple ice sheet model and find that the equilibrium ice volume is approximately 1 m SLE (meters sea level equivalent) smaller when the simple model is forced with fluctuating temperatures as opposed to a stable climate. It is therefore important to consider the effect of interannual temperature fluctuations when designing long experiments such as paleo-spin-ups. We show how the magnitude of the potential bias can be quantified statistically. For recent simulations of the Greenland Ice Sheet, we estimate the bias to be 30 Gt yr-1 (24-59 Gt yr-1, 95 % credibility) for a warming of 3 °C above preindustrial values, or 13 % (10-25, 95 % credibility) of the present-day rate of ice loss. Models of the Greenland Ice Sheet show a collapse threshold beyond which the ice sheet becomes unsustainable. The proximity of the threshold will be underestimated if temperature fluctuations are not taken into account. We estimate the bias to be 0.12 °C (0.10-0.18 °C, 95 % credibility) for a recent estimate of the threshold. In light of our findings it is important to gauge the extent to which this increased variability will influence the mass balance of the ice sheets.

Scaffolding students’ assignments

DEFF Research Database (Denmark)

Slot, Marie Falkesgaard

2013-01-01

This article discusses scaffolding in typical student assignments in mother tongue learning materials in upper secondary education in Denmark and the United Kingdom. It has been determined that assignments do not have sufficient scaffolding end features to help pupils understand concepts and build...... objects. The article presents the results of empirical research on tasks given in Danish and British learning materials. This work is based on a further development of my PhD thesis: “Learning materials in the subject of Danish” (Slot 2010). The main focus is how cognitive models (and subsidiary explicit...... learning goals) can help students structure their argumentative and communica-tive learning processes, and how various multimodal representations can give more open-ended learning possibilities for collaboration. The article presents a short introduction of the skills for 21st century learning and defines...

Sheet Beam Klystron Instability Analysis

International Nuclear Information System (INIS)

Bane, K.

2009-01-01

Using the principle of energy balance we develop a 2D theory for calculating growth rates of instability in a two-cavity model of a sheet beam klystron. An important ingredient is a TE-like mode in the gap that also gives a longitudinal kick to the beam. When compared with a self-consistent particle-in-cell calculation, with sheet beam klystron-type parameters, agreement is quite good up to half the design current, 65 A; at full current, however, other, current-dependent effects come in and the results deviate significantly

Bi-directional electrons in the near-Earth plasma sheet

Directory of Open Access Journals (Sweden)

K. Shiokawa

2003-07-01

Full Text Available We have studied the occurrence characteristics of bi-directional electron pitch angle anisotropy (enhanced flux in field-aligned directions, F^ /F|| > 1.5 at energies of 0.1–30 keV using plasma and magnetic field data from the AMPTE/IRM satellite in the near-Earth plasma sheet. The occurrence rate increases in the tailward direction from XGSM = - 9 RE to - 19 RE . The occurrence rate is also enhanced in the midnight sector, and furthermore, whenever the elevation angle of the magnetic field is large while the magnetic field intensity is small, B ~ 15 nT. From these facts, we conclude that the bi-directional electrons in the central plasma sheet are produced mainly in the vicinity of the neutral sheet and that the contribution from ionospheric electrons is minor. A high occurrence is also found after earthward high-speed ion flows, suggesting Fermi-type field-aligned electron acceleration in the neutral sheet. Occurrence characteristics of bi-directional electrons in the plasma sheet boundary layer are also discussed.Key words. Magnetospheric physics (magnetospheric configuration and dynamics; magnetotail; plasma sheet

Firm Investment and Balance-Sheet Problems in Japan

OpenAIRE

Toshitaka Sekine

1999-01-01

This paper investigates whether balance-sheet conditions of firms and their main banks matter for firm investment behavior using dynamic corporate panel data in Japan for the period 1985-95. It finds that smaller non-bond issuing firms were facing liquidity constraints; these firms’ balance-sheet conditions (the debt asset ratios) affected their investment from the midst of the bubble era by influencing main banks’ lending to them; and the deterioration of their main banks’ balance-sheet cond...

Energization of the Ring Current through Convection of Substorm Enhancements of the Plasma Sheet Source.

Science.gov (United States)

Menz, A.; Kistler, L. M.; Mouikis, C.; Spence, H. E.; Henderson, M. G.; Matsui, H.

2017-12-01

It has been shown that electric field strength and night-side plasma sheet density are the two best predictors of the adiabatic energy gain of the ring current during geomagnetic storms (Liemohn and Khazanov, 2005). While H+ dominates the ring current during quiet times, O+ can contribute substantially during geomagnetic storms. Substorm activity provides a mechanism to enhance the energy density of O+ in the plasma sheet during geomagnetic storms, which is then convected adiabatically into the inner-magnetosphere. Using the Van Allen Probes data in the the plasma sheet source region (defined as L>5.5 during storms) and the inner magnetosphere, along with LANL-GEO data to identify substorm injection times, we show that adiabatic convection of O+ enhancements in the source region can explain the observed enhancements in the inner magnetosphere. We use the UNH-IMEF electric field model to calculate drift times from the source region to the inner magnetosphere to test whether enhancements in the inner-magnetosphere can be explained by dipolarization driven enhancements in the plasma sheet source hours before.

Growth and Characterization of PbO Nano rods Grown using Facile Oxidation of Lead Sheet

International Nuclear Information System (INIS)

Yousefi, R.; Sheini, F.J.; Saaedi, A.; Cheraghizade, M.

2015-01-01

PbO nano rods were synthesized by oxidation of lead sheets under an oxygen ambience with different temperatures at 330, 400, 450 and 550 degree Celsius in a tube furnace. Scanning electron microscope (SEM) results showed that the nano rods started growing on the sheet that was placed at 330 degree Celsius. On the other hand, by increasing of the temperature to 550 degree Celsius more nano rods appeared on the Pb sheet, which were lied on the lead sheet. X-ray diffraction pattern (XRD) indicated that the nano rods had α-PbO structures. However, a few β-PbO phases also appeared for the nano rods. Raman measurements confirmed the XRD results and indicated two Raman active modes that belonged to α-PbO phase for the nano rods. In addition, the Raman spectrum of the nano rods showed a weak peak of the β-PbO structure. The optical properties of the products were characterized using a room temperature photoluminescence (PL) technique. The PL result indicated a band gap for the PbO nano rods in the visible region. (author)

Mars - robust automatic backbone assignment of proteins

International Nuclear Information System (INIS)

Jung, Young-Sang; Zweckstetter, Markus

2004-01-01

MARS a program for robust automatic backbone assignment of 13 C/ 15 N labeled proteins is presented. MARS does not require tight thresholds for establishing sequential connectivity or detailed adjustment of these thresholds and it can work with a wide variety of NMR experiments. Using only 13 C α / 13 C β connectivity information, MARS allows automatic, error-free assignment of 96% of the 370-residue maltose-binding protein. MARS can successfully be used when data are missing for a substantial portion of residues or for proteins with very high chemical shift degeneracy such as partially or fully unfolded proteins. Other sources of information, such as residue specific information or known assignments from a homologues protein, can be included into the assignment process. MARS exports its result in SPARKY format. This allows visual validation and integration of automated and manual assignment

Antibubbles and fine cylindrical sheets of air

NARCIS (Netherlands)

Beilharz, D.; Guyon, A.; Li, E.Q.; Thoraval, Marie-Jean; Thoroddsen, S.T.

2015-01-01

Drops impacting at low velocities onto a pool surface can stretch out thin hemispherical sheets of air between the drop and the pool. These air sheets can remain intact until they reach submicron thicknesses, at which point they rupture to form a myriad of microbubbles. By impacting a

Reducing Test Anxiety while Increasing Learning: The Cheat Sheet

Science.gov (United States)

Erbe, Brigitte

2007-01-01

Student learning is greatly enhanced by studying prior to an exam. Allowing students to prepare a cheat sheet for the exam helps structure this study time and deepens learning. The crib sheet is well defined: one double-sided page of notes. An award for the best and most creative cheat sheet allows the instructor to appreciate the students'…

New assignment of 14N NQR spectral lines for tetrazoles derivatives

Science.gov (United States)

Mamadazizov, Sultonazar; Shelyapina, Marina G.; Kupriyanova, Galina S.; Mozzhukhin, George V.

2018-04-01

In recent years, considerable interest has been shown in the study of tetrazole derivatives, which attract attention as highly nitrogenous compounds for use as an isosteric substitutes for various functional groups that leads to creation of novel biologically active substances. NQR techniques, being sensitive to the local environment of 14N nuclei, provide great opportunities to study these new substances. To make investigation of complex compounds containing tetrazoles derivatives easier and more reliable a correctly assigned 14N NQR spectra of tetrazoles are required. Here we report on the results of our DFT B3LYP calculations of 14N NQR spectral parameters (quadrupole coupling constant Qcc and the asymmetry parameter of the electric field gradient η) for tetrazole, 5-aminotetrazole and 5-aminotetrazole monohydrate. It has been found that the commonly accepted assignment of the 14N NQR spectral lines for these molecules is incorrect. A new assignment for these molecules is proposed.

Ice sheet hydrology from observations

Energy Technology Data Exchange (ETDEWEB)

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

2010-11-15

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

Ice sheet hydrology from observations

International Nuclear Information System (INIS)

Jansson, Peter

2010-11-01

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

Assignment of element and isotope factors

International Nuclear Information System (INIS)

Schneider, R.A.

1984-01-01

Element and isotope factors are assigned in the NICS internal accounting system at the Exxon Fuel Fabrication Facility on the basis of coded information included on the material transfer documents. This paper explains more fully the manner in which NICS assigns these factors

FORMATION AND RECONNECTION OF THREE-DIMENSIONAL CURRENT SHEETS IN THE SOLAR CORONA

International Nuclear Information System (INIS)

Edmondson, J. K.; Antiochos, S. K.; DeVore, C. R.; Zurbuchen, T. H.

2010-01-01

Current-sheet formation and magnetic reconnection are believed to be the basic physical processes responsible for much of the activity observed in astrophysical plasmas, such as the Sun's corona. We investigate these processes for a magnetic configuration consisting of a uniform background field and an embedded line dipole, a topology that is expected to be ubiquitous in the corona. This magnetic system is driven by a uniform horizontal flow applied at the line-tied photosphere. Although both the initial field and the driver are translationally symmetric, the resulting evolution is calculated using a fully three-dimensional (3D) magnetohydrodynamic simulation with adaptive mesh refinement that resolves the current sheet and reconnection dynamics in detail. The advantage of our approach is that it allows us to directly apply the vast body of knowledge gained from the many studies of two-dimensional (2D) reconnection to the fully 3D case. We find that a current sheet forms in close analogy to the classic Syrovatskii 2D mechanism, but the resulting evolution is different than expected. The current sheet is globally stable, showing no evidence for a disruption or a secondary instability even for aspect ratios as high as 80:1. The global evolution generally follows the standard Sweet-Parker 2D reconnection model except for an accelerated reconnection rate at a very thin current sheet, due to the tearing instability and the formation of magnetic islands. An interesting conclusion is that despite the formation of fully 3D structures at small scales, the system remains close to 2D at global scales. We discuss the implications of our results for observations of the solar corona.

Laser Indirect Shock Welding of Fine Wire to Metal Sheet.

Science.gov (United States)

Wang, Xiao; Huang, Tao; Luo, Yapeng; Liu, Huixia

2017-09-12

The purpose of this paper is to present an advanced method for welding fine wire to metal sheet, namely laser indirect shock welding (LISW). This process uses silica gel as driver sheet to accelerate the metal sheet toward the wire to obtain metallurgical bonding. A series of experiments were implemented to validate the welding ability of Al sheet/Cu wire and Al sheet/Ag wire. It was found that the use of a driver sheet can maintain high surface quality of the metal sheet. With the increase of laser pulse energy, the bonding area of the sheet/wire increased and the welding interfaces were nearly flat. Energy dispersive spectroscopy (EDS) results show that the intermetallic phases were absent and a short element diffusion layer which would limit the formation of the intermetallic phases emerging at the welding interface. A tensile shear test was used to measure the mechanical strength of the welding joints. The influence of laser pulse energy on the tensile failure modes was investigated, and two failure modes, including interfacial failure and failure through the wire, were observed. The nanoindentation test results indicate that as the distance to the welding interface decreased, the microhardness increased due to the plastic deformation becoming more violent.

Inferential backbone assignment for sparse data

International Nuclear Information System (INIS)

Vitek, Olga; Bailey-Kellogg, Chris; Craig, Bruce; Vitek, Jan

2006-01-01

This paper develops an approach to protein backbone NMR assignment that effectively assigns large proteins while using limited sets of triple-resonance experiments. Our approach handles proteins with large fractions of missing data and many ambiguous pairs of pseudoresidues, and provides a statistical assessment of confidence in global and position-specific assignments. The approach is tested on an extensive set of experimental and synthetic data of up to 723 residues, with match tolerances of up to 0.5 ppm for C α and C β resonance types. The tests show that the approach is particularly helpful when data contain experimental noise and require large match tolerances. The keys to the approach are an empirical Bayesian probability model that rigorously accounts for uncertainty in the data at all stages in the analysis, and a hybrid stochastic tree-based search algorithm that effectively explores the large space of possible assignments

Large patternable metal nanoparticle sheets by photo/e-beam lithography

Science.gov (United States)

Saito, Noboru; Wang, Pangpang; Okamoto, Koichi; Ryuzaki, Sou; Tamada, Kaoru

2017-10-01

Techniques for micro/nano-scale patterning of large metal nanoparticle sheets can potentially be used to realize high-performance photoelectronic devices because the sheets provide greatly enhanced electrical fields around the nanoparticles due to localized surface plasmon resonances. However, no single metal nanoparticle sheet currently exists with sufficient durability for conventional lithographical processes. Here, we report large photo and/or e-beam lithographic patternable metal nanoparticle sheets with improved durability by incorporating molecular cross-linked structures between nanoparticles. The cross-linked structures were easily formed by a one-step chemical reaction; immersing a single nanoparticle sheet consisting of core metals, to which capping molecules ionically bond, in a dithiol ethanol solution. The ligand exchange reaction processes were discussed in detail, and we demonstrated 20 μm wide line and space patterns, and a 170 nm wide line of the silver nanoparticle sheets.

Optimal Design of Sheet Pile Wall Embedded in Clay

Science.gov (United States)

Das, Manas Ranjan; Das, Sarat Kumar

2015-09-01

Sheet pile wall is a type of flexible earth retaining structure used in waterfront offshore structures, river protection work and temporary supports in foundations and excavations. Economy is an essential part of a good engineering design and needs to be considered explicitly in obtaining an optimum section. By considering appropriate embedment depth and sheet pile section it may be possible to achieve better economy. This paper describes optimum design of both cantilever and anchored sheet pile wall penetrating clay using a simple optimization tool Microsoft Excel ® Solver. The detail methodology and its application with examples are presented for cantilever and anchored sheet piles. The effects of soil properties, depth of penetration and variation of ground water table on the optimum design are also discussed. Such a study will help professional while designing the sheet pile wall penetrating clay.

How might the North American ice sheet influence the northwestern Eurasian climate?

Science.gov (United States)

Beghin, P.; Charbit, S.; Dumas, C.; Kageyama, M.; Ritz, C.

2015-10-01

It is now widely acknowledged that past Northern Hemisphere ice sheets covering Canada and northern Europe at the Last Glacial Maximum (LGM) exerted a strong influence on climate by causing changes in atmospheric and oceanic circulations. In turn, these changes may have impacted the development of the ice sheets themselves through a combination of different feedback mechanisms. The present study is designed to investigate the potential impact of the North American ice sheet on the surface mass balance (SMB) of the Eurasian ice sheet driven by simulated changes in the past glacial atmospheric circulation. Using the LMDZ5 atmospheric circulation model, we carried out 12 experiments under constant LGM conditions for insolation, greenhouse gases and ocean. In these experiments, the Eurasian ice sheet is removed. The 12 experiments differ in the North American ice-sheet topography, ranging from a white and flat (present-day topography) ice sheet to a full-size LGM ice sheet. This experimental design allows the albedo and the topographic impacts of the North American ice sheet onto the climate to be disentangled. The results are compared to our baseline experiment where both the North American and the Eurasian ice sheets have been removed. In summer, the sole albedo effect of the American ice sheet modifies the pattern of planetary waves with respect to the no-ice-sheet case, resulting in a cooling of the northwestern Eurasian region. By contrast, the atmospheric circulation changes induced by the topography of the North American ice sheet lead to a strong decrease of this cooling. In winter, the Scandinavian and the Barents-Kara regions respond differently to the American ice-sheet albedo effect: in response to atmospheric circulation changes, Scandinavia becomes warmer and total precipitation is more abundant, whereas the Barents-Kara area becomes cooler with a decrease of convective processes, causing a decrease of total precipitation. The gradual increase of the

Breakup characteristics of power-law liquid sheets formed by two impinging jets

International Nuclear Information System (INIS)

Bai, Fuqiang; Diao, Hai; Chang, Qing; Wang, Endong; Du, Qing; Zhang, Mengzheng

2014-01-01

The breakup characteristics of the shear-thinning power-law liquid sheets formed by two impinging jets have been investigated with the shadowgraph technique. This paper focuses on the effects of spray parameters (jet velocity), physical parameters (viscosity) and geometry parameters (impinging angle and nozzle cross-sectional shape) on the breakup behaviors of liquid sheets. The breakup mode, sheet length and expansion angle of the sheet are extracted from the spray images obtained by a high speed camera. Impinging angle and Weber number play the similar roles in promoting the breakup of liquid sheets. With the increase of jet velocity, five different breakup modes are observed and the expansion angle increases consistently after the closed-rim mode while the sheet length first increases and then decreases. But there exists a concave consisting of a fierce drop and a second rising process on the sheet length curve for the fluid with smaller viscosity. Different nozzle cross-sectional shapes emphasize significant effects on the sheet length and expansion angle of liquid sheets. At a fixed Weber number, the liquid sheet with greater viscosity has a greater sheet length and a smaller expansion angle due to the damping effect of viscosity. (papers)

Fatigue analysis of a PWR steam generator tube sheet

International Nuclear Information System (INIS)

Billon, F.; Buchalet, C.; Poudroux, G.

1985-01-01

The fatigue analysis of a PWR steam generator (S.G) tube sheet is threefold. First, the flow, pressure and temperature variations during the design transients are defined for both the primary fluid and the normal and auxiliary feedwater. Second, the flow, velocities, pressure and temperature variations of the secondary fluid at the bottom of the downcomer and above the tube sheet are determined for the transients considered. Finally, the corresponding temperatures and stresses in the tube sheet are calculated and the usage factors determined at various locations in the tube sheet. The currently available standard design transients for the primary fluid and the feedwater are too conservative to be utilized as such in the fatigue analysis of the S.G. tube sheets. Thus, a detailed examination and reappraisal of each operating transient was performed. The revised design conditions are used as inputs to the calculation model TEMPTRON. TEMPTRON determines the mixing conditions between the feedwater and the recirculation fluid from the S.G. feedwater nozzles to the center of the tube sheet via the downcomer. The fluid parameters, flow rate and velocity, temperature and pressure variations, as a function of the time during the transients are obtained. Finally, the usage factors at various locations on the tube sheet are derived using the standard ASME section III method

Grounding line transient response in marine ice sheet models

Directory of Open Access Journals (Sweden)

A. S. Drouet

2013-03-01

Full Text Available Marine ice-sheet stability is mostly controlled by the dynamics of the grounding line, i.e. the junction between the grounded ice sheet and the floating ice shelf. Grounding line migration has been investigated within the framework of MISMIP (Marine Ice Sheet Model Intercomparison Project, which mainly aimed at investigating steady state solutions. Here we focus on transient behaviour, executing short-term simulations (200 yr of a steady ice sheet perturbed by the release of the buttressing restraint exerted by the ice shelf on the grounded ice upstream. The transient grounding line behaviour of four different flowline ice-sheet models has been compared. The models differ in the physics implemented (full Stokes and shallow shelf approximation, the numerical approach, as well as the grounding line treatment. Their overall response to the loss of buttressing is found to be broadly consistent in terms of grounding line position, rate of surface elevation change and surface velocity. However, still small differences appear for these latter variables, and they can lead to large discrepancies (> 100% observed in terms of ice sheet contribution to sea level when cumulated over time. Despite the recent important improvements of marine ice-sheet models in their ability to compute steady state configurations, our results question the capacity of these models to compute short-term reliable sea-level rise projections.

A laser sheet self-calibration method for scanning PIV

Science.gov (United States)

Knutsen, Anna N.; Lawson, John M.; Dawson, James R.; Worth, Nicholas A.

2017-10-01

Knowledge of laser sheet position, orientation, and thickness is a fundamental requirement of scanning PIV and other laser-scanning methods. This paper describes the development and evaluation of a new laser sheet self-calibration method for stereoscopic scanning PIV, which allows the measurement of these properties from particle images themselves. The approach is to fit a laser sheet model by treating particles as randomly distributed probes of the laser sheet profile, whose position is obtained via a triangulation procedure enhanced by matching particle images according to their variation in brightness over a scan. Numerical simulations and tests with experimental data were used to quantify the sensitivity of the method to typical experimental error sources and validate its performance in practice. The numerical simulations demonstrate the accurate recovery of the laser sheet parameters over range of different seeding densities and sheet thicknesses. Furthermore, they show that the method is robust to significant image noise and camera misalignment. Tests with experimental data confirm that the laser sheet model can be accurately reconstructed with no impairment to PIV measurement accuracy. The new method is more efficient and robust in comparison with the standard (self-) calibration approach, which requires an involved, separate calibration step that is sensitive to experimental misalignments. The method significantly improves the practicality of making accurate scanning PIV measurements and broadens its potential applicability to scanning systems with significant vibrations.

16 CFR 460.15 - How installers must handle fact sheets.

Science.gov (United States)

2010-01-01

... ADVERTISING OF HOME INSULATION § 460.15 How installers must handle fact sheets. If you are an installer, you... from you, you must show them the fact sheet(s) for the type(s) of insulation they want. You can decide...

Ice sheets on plastically-yielding beds

Science.gov (United States)

Hewitt, Ian

2016-11-01

Many fast flowing regions of ice sheets are underlain by a layer of water-saturated sediments, or till. The rheology of the till has been the subject of some controversy, with laboratory tests suggesting almost perfectly plastic behaviour (stress independent of strain rate), but many models adopting a pseudo-viscous description. In this work, we consider the behaviour of glaciers underlain by a plastic bed. The ice is treated as a viscous gravity current, on a bed that allows unconstrained slip above a critical yield stress. This simplified description allows rapid sliding, and aims to investigate 'worst-case' scenarios of possible ice-sheet disintegration. The plastic bed results in an approximate ice-sheet geometry that is primarily controlled by force balance, whilst ice velocity is determined from mass conservation (rather than the other way around, as standard models would hold). The stability of various states is considered, and particular attention is given to the pace at which transitions between unstable states can occur. Finally, we observe that the strength of basal tills depends strongly on pore pressure, and combine the model with a description of subglacial hydrology. Implications for the present-day ice sheets in Greenland and Antarctica will be discussed. Funding: ERC Marie Curie FP7 Career Integration Grant.

Pseudomonas - Fact Sheet

OpenAIRE

Public Health Agency

2012-01-01

Fact sheet on Pseudomonas, including:What is Pseudomonas?What infections does it cause?Who is susceptible to pseudomonas infection?How will I know if I have pseudomonas infection?How can Pseudomonas be prevented from spreading?How can I protect myself from Pseudomonas?How is Pseudomonas infection treated?

Continuous development of current sheets near and away from magnetic nulls

International Nuclear Information System (INIS)

Kumar, Sanjay; Bhattacharyya, R.

2016-01-01

The presented computations compare the strength of current sheets which develop near and away from the magnetic nulls. To ensure the spontaneous generation of current sheets, the computations are performed congruently with Parker's magnetostatic theorem. The simulations evince current sheets near two dimensional and three dimensional magnetic nulls as well as away from them. An important finding of this work is in the demonstration of comparative scaling of peak current density with numerical resolution, for these different types of current sheets. The results document current sheets near two dimensional magnetic nulls to have larger strength while exhibiting a stronger scaling than the current sheets close to three dimensional magnetic nulls or away from any magnetic null. The comparative scaling points to a scenario where the magnetic topology near a developing current sheet is important for energetics of the subsequent reconnection.

Microbial processes in glaciers and permafrost. A literature study on microbiology affecting groundwater at ice sheet melting

International Nuclear Information System (INIS)

Hallbeck, Lotta

2009-10-01

A repository for spent nuclear fuel will remain for hundred thousands of years. During this period, several ice ages will most likely take place. To understand the effect of melt water from ice sheets on the repository, the microbiological processes of oxygen reduction has to be elucidated. This report is a compilation of the present knowledge about biological activity in glacier environments. These environments consist of many different parts which have their own biological character depending on the prevailing physical and chemical conditions. There are, for example, ice sheets and glaciers, glacial streams and rivers, soil and water beneath the ice, soil and water in front of and beside ice sheets and glacier and deep groundwater beneath the ice. The microbiological processes of importance are consumption of oxygen by aerobic microorganisms, anaerobic organisms and their reduced metabolites, like sulphide, acetate and methane, which can act as reducing agents in biological or chemical oxygen reduction. The lithotrophic type (inorganic energy source) of metabolism is important in these cold environments. There are also microbiological processes important to radionuclide transport and the production of complexing agents, biological colloids and biofilms. The study of microbial processes in glacier and ice sheet environments is still a young scientific niche. The studies have so far mostly been concentrated to ice surfaces and the subglacial environment. The most important findings from the literature study are as follows. Primary production is ongoing in snow cover and on ice surfaces of glaciers and ice sheets. The production is dependent on the location, because of temperature and solar radiation, but also on the prevailing state of the glacier. On surfaces and in the snow cover, heterotrophic microorganisms consume oxygen and organic material. In surface ice structures anaerobic conditions may occur. The subglacial environment is very active with several types

Microbial processes in glaciers and permafrost. A literature study on microbiology affecting groundwater at ice sheet melting

Energy Technology Data Exchange (ETDEWEB)

Hallbeck, Lotta (Microbial Analytics Sweden AB, Moelnlycke (Sweden))

2009-10-15

A repository for spent nuclear fuel will remain for hundred thousands of years. During this period, several ice ages will most likely take place. To understand the effect of melt water from ice sheets on the repository, the microbiological processes of oxygen reduction has to be elucidated. This report is a compilation of the present knowledge about biological activity in glacier environments. These environments consist of many different parts which have their own biological character depending on the prevailing physical and chemical conditions. There are, for example, ice sheets and glaciers, glacial streams and rivers, soil and water beneath the ice, soil and water in front of and beside ice sheets and glacier and deep groundwater beneath the ice. The microbiological processes of importance are consumption of oxygen by aerobic microorganisms, anaerobic organisms and their reduced metabolites, like sulphide, acetate and methane, which can act as reducing agents in biological or chemical oxygen reduction. The lithotrophic type (inorganic energy source) of metabolism is important in these cold environments. There are also microbiological processes important to radionuclide transport and the production of complexing agents, biological colloids and biofilms. The study of microbial processes in glacier and ice sheet environments is still a young scientific niche. The studies have so far mostly been concentrated to ice surfaces and the subglacial environment. The most important findings from the literature study are as follows. Primary production is ongoing in snow cover and on ice surfaces of glaciers and ice sheets. The production is dependent on the location, because of temperature and solar radiation, but also on the prevailing state of the glacier. On surfaces and in the snow cover, heterotrophic microorganisms consume oxygen and organic material. In surface ice structures anaerobic conditions may occur. The subglacial environment is very active with several types

The Potato People in "School Daze": Presented by Theatre Beyond Words. Cue Sheet for Students.

Science.gov (United States)

Briley, Rachel

This performance guide is designed for teachers to use with students before and after a performance of the Potato People in "School Daze." The guide, called a "Cuesheet," contains seven pages of reproducible activity sheets for use in class with activities and discussion questions on the following topics: (1) Meet the…

Dynamic Antarctic ice sheet during the early to mid-Miocene

Science.gov (United States)

Gasson, Edward; DeConto, Robert M.; Pollard, David; Levy, Richard H.

2016-03-01

Geological data indicate that there were major variations in Antarctic ice sheet volume and extent during the early to mid-Miocene. Simulating such large-scale changes is problematic because of a strong hysteresis effect, which results in stability once the ice sheets have reached continental size. A relatively narrow range of atmospheric CO2 concentrations indicated by proxy records exacerbates this problem. Here, we are able to simulate large-scale variability of the early to mid-Miocene Antarctic ice sheet because of three developments in our modeling approach. (i) We use a climate-ice sheet coupling method utilizing a high-resolution atmospheric component to account for ice sheet-climate feedbacks. (ii) The ice sheet model includes recently proposed mechanisms for retreat into deep subglacial basins caused by ice-cliff failure and ice-shelf hydrofracture. (iii) We account for changes in the oxygen isotopic composition of the ice sheet by using isotope-enabled climate and ice sheet models. We compare our modeling results with ice-proximal records emerging from a sedimentological drill core from the Ross Sea (Andrill-2A) that is presented in a companion article. The variability in Antarctic ice volume that we simulate is equivalent to a seawater oxygen isotope signal of 0.52-0.66‰, or a sea level equivalent change of 30-36 m, for a range of atmospheric CO2 between 280 and 500 ppm and a changing astronomical configuration. This result represents a substantial advance in resolving the long-standing model data conflict of Miocene Antarctic ice sheet and sea level variability.

Microstructural Changes in Brazing Sheet due to Solid-Liquid Interaction

NARCIS (Netherlands)

Wittebrood, A.J.

2009-01-01

Aluminium brazing sheet is the material of choice to produce automotive heat exchangers. Although in Dutch the official translation of aluminium brazing sheet is “aluminium hardsoldeerplaat” the English name is used in the industry. Aluminium brazing sheet is basically a sandwich material and

Transfer of fibroblast sheets cultured on thermoresponsive dishes with membranes.

Science.gov (United States)

Kawecki, Marek; Kraut, Małgorzata; Klama-Baryła, Agnieszka; Łabuś, Wojciech; Kitala, Diana; Nowak, Mariusz; Glik, Justyna; Sieroń, Aleksander L; Utrata-Wesołek, Alicja; Trzebicka, Barbara; Dworak, Andrzej; Szweda, Dawid

2016-06-01

In cell or tissue engineering, it is essential to develop a support for cell-to-cell adhesion, which leads to the generation of cell sheets connected by extracellular matrix. Such supports must be hydrophobic and should result in a detachable cell sheet. A thermoresponsive support that enables the cultured cell sheet to detach using only a change in temperature could be an interesting alternative in regenerative medicine. The aim of this study was to evaluate plates covered with thermoresponsive polymers as supports for the formation of fibroblast sheets and to develop a damage-free procedure for cell sheet transfer with the use of membranes as transfer tools. Human skin fibroblasts were seeded on supports coated with a thermoresponsive polymer: commercial UpCell™ dishes (NUNC™) coated with thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) and dishes coated with thermoresponsive poly(tri(ethylene glycol) monoethyl ether methacrylate) (P(TEGMA-EE)). Confluent fibroblast sheets were effectively cultured and harvested from both commercial PNIPAM-coated dishes and laboratory P(TEGMA-EE)-coated dishes. To transfer a detached cell sheet, two membranes, Immobilon-P(®) and SUPRATHEL(®), were examined. The use of SUPRATHEL for relocating the cell sheets opens a new possibility for the clinical treatment of wounds. This study established the background for implementing thermoresponsive supports for transplanting in vitro cultured fibroblasts.

Endogenous Sheet-Averaged Tension Within a Large Epithelial Cell Colony.

Science.gov (United States)

Dumbali, Sandeep P; Mei, Lanju; Qian, Shizhi; Maruthamuthu, Venkat

2017-10-01

Epithelial cells form quasi-two-dimensional sheets that function as contractile media to effect tissue shape changes during development and homeostasis. Endogenously generated intrasheet tension is a driver of such changes, but has predominantly been measured in the presence of directional migration. The nature of epithelial cell-generated forces transmitted over supracellular distances, in the absence of directional migration, is thus largely unclear. In this report, we consider large epithelial cell colonies which are archetypical multicell collectives with extensive cell-cell contacts but with a symmetric (circular) boundary. Using the traction force imbalance method (TFIM) (traction force microscopy combined with physical force balance), we first show that one can determine the colony-level endogenous sheet forces exerted at the midline by one half of the colony on the other half with no prior assumptions on the uniformity of the mechanical properties of the cell sheet. Importantly, we find that this colony-level sheet force exhibits large variations with orientation-the difference between the maximum and minimum sheet force is comparable to the average sheet force itself. Furthermore, the sheet force at the colony midline is largely tensile but the shear component exhibits significantly more variation with orientation. We thus show that even an unperturbed epithelial colony with a symmetric boundary shows significant directional variation in the endogenous sheet tension and shear forces that subsist at the colony level.

Filament structure, organization, and dynamics in MreB sheets.

Science.gov (United States)

Popp, David; Narita, Akihiro; Maeda, Kayo; Fujisawa, Tetsuro; Ghoshdastider, Umesh; Iwasa, Mitsusada; Maéda, Yuichiro; Robinson, Robert C

2010-05-21

In vivo fluorescence microscopy studies of bacterial cells have shown that the bacterial shape-determining protein and actin homolog, MreB, forms cable-like structures that spiral around the periphery of the cell. The molecular structure of these cables has yet to be established. Here we show by electron microscopy that Thermatoga maritime MreB forms complex, several mum long multilayered sheets consisting of diagonally interwoven filaments in the presence of either ATP or GTP. This architecture, in agreement with recent rheological measurements on MreB cables, may have superior mechanical properties and could be an important feature for maintaining bacterial cell shape. MreB polymers within the sheets appear to be single-stranded helical filaments rather than the linear protofilaments found in the MreB crystal structure. Sheet assembly occurs over a wide range of pH, ionic strength, and temperature. Polymerization kinetics are consistent with a cooperative assembly mechanism requiring only two steps: monomer activation followed by elongation. Steady-state TIRF microscopy studies of MreB suggest filament treadmilling while high pressure small angle x-ray scattering measurements indicate that the stability of MreB polymers is similar to that of F-actin filaments. In the presence of ADP or GDP, long, thin cables formed in which MreB was arranged in parallel as linear protofilaments. This suggests that the bacterial cell may exploit various nucleotides to generate different filament structures within cables for specific MreB-based functions.

Influence of temperature fluctuations on equilibrium ice sheet volume

Directory of Open Access Journals (Sweden)

T. B. Mikkelsen

2018-01-01

Full Text Available Forecasting the future sea level relies on accurate modeling of the response of the Greenland and Antarctic ice sheets to changing temperatures. The surface mass balance (SMB of the Greenland Ice Sheet (GrIS has a nonlinear response to warming. Cold and warm anomalies of equal size do not cancel out and it is therefore important to consider the effect of interannual fluctuations in temperature. We find that the steady-state volume of an ice sheet is biased toward larger size if interannual temperature fluctuations are not taken into account in numerical modeling of the ice sheet. We illustrate this in a simple ice sheet model and find that the equilibrium ice volume is approximately 1 m SLE (meters sea level equivalent smaller when the simple model is forced with fluctuating temperatures as opposed to a stable climate. It is therefore important to consider the effect of interannual temperature fluctuations when designing long experiments such as paleo-spin-ups. We show how the magnitude of the potential bias can be quantified statistically. For recent simulations of the Greenland Ice Sheet, we estimate the bias to be 30 Gt yr−1 (24–59 Gt yr−1, 95 % credibility for a warming of 3 °C above preindustrial values, or 13 % (10–25, 95 % credibility of the present-day rate of ice loss. Models of the Greenland Ice Sheet show a collapse threshold beyond which the ice sheet becomes unsustainable. The proximity of the threshold will be underestimated if temperature fluctuations are not taken into account. We estimate the bias to be 0.12 °C (0.10–0.18 °C, 95 % credibility for a recent estimate of the threshold. In light of our findings it is important to gauge the extent to which this increased variability will influence the mass balance of the ice sheets.

Continuous liquid sheet generator for ion stripping

International Nuclear Information System (INIS)

Gavin, B.; Batson, P.; Leemann, B.; Rude, B.

1984-10-01

Many of the technical problems of generating a large thin liquid sheet from 0.02 to 0.20 μm thick (3 to 40 μgm/cm 2 ) have been solved. It is shown that this perennial sheet is stable and consonant in dimension. Several ion beam species from the SuperHILAC have been used for evaluation; at 0.11 MeV/n. In one of three modes this sheet serves as an equivalent substitute for a carbon foil. The second mode is characterized by a solid-like charge state distribution but with a varying fraction of unstripped ions. The third mode gives stripping performance akin to a vapor stripping medium. 9 references, 7 figures

Simulation spread sheet of Angra-1 secondary circuit

International Nuclear Information System (INIS)

Futuro, F.L.; Rucos, J.; Ogando, A.; Maprelian, E.; Bassel, W.S.; Baptista Filho, B.D.

2000-01-01

The efficient operation of a Nuclear Power Plant (NPP) requires the continuous identification of derivations in the main operating parameters. The identification and analysis of those derivations allow someone to detect the degradation of instruments or even of any equipment. In order to study this problem the group of thermal generation of Angra 1 NPP, devised the use of a Microsoft Excel spread sheet for the automation of Angra 1 thermal balance. In the set of simulation spread sheets, measured values of the secondary system main parameters were compared with project values for a given reactor power level and condenser pressure. The spread sheets provide the turbines power and efficiency and do the plant thermal balance. This work presents a general description of the spread sheets set and a real case analysis of Angra 1 NPP, showing its precision and use easiness. (author)

The Potsdam Parallel Ice Sheet Model (PISM-PIK) - Part 2: Dynamic equilibrium simulation of the Antarctic ice sheet

Science.gov (United States)

Martin, M. A.; Winkelmann, R.; Haseloff, M.; Albrecht, T.; Bueler, E.; Khroulev, C.; Levermann, A.

2011-09-01

We present a dynamic equilibrium simulation of the ice sheet-shelf system on Antarctica with the Potsdam Parallel Ice Sheet Model (PISM-PIK). The simulation is initialized with present-day conditions for bed topography and ice thickness and then run to steady state with constant present-day surface mass balance. Surface temperature and sub-shelf basal melt distribution are parameterized. Grounding lines and calving fronts are free to evolve, and their modeled equilibrium state is compared to observational data. A physically-motivated calving law based on horizontal spreading rates allows for realistic calving fronts for various types of shelves. Steady-state dynamics including surface velocity and ice flux are analyzed for whole Antarctica and the Ronne-Filchner and Ross ice shelf areas in particular. The results show that the different flow regimes in sheet and shelves, and the transition zone between them, are captured reasonably well, supporting the approach of superposition of SIA and SSA for the representation of fast motion of grounded ice. This approach also leads to a natural emergence of sliding-dominated flow in stream-like features in this new 3-D marine ice sheet model.

75 FR 55340 - Recovery Fact Sheet 9580.100, Mold Remediation

Science.gov (United States)

2010-09-10

...] Recovery Fact Sheet 9580.100, Mold Remediation AGENCY: Federal Emergency Management Agency, DHS. ACTION... accepting comments on Recovery Fact Sheet RP9580.100, Mold Remediation. DATES: Comments must be received by... 20472-3100. II. Background The Recovery Fact Sheet RP9580.100, Mold Remediation, identifies the expenses...

32 CFR 884.2 - Assigned responsibilities.

Science.gov (United States)

2010-07-01

... OF PERSONNEL TO UNITED STATES CIVILIAN AUTHORITIES FOR TRIAL § 884.2 Assigned responsibilities. (a... 32 National Defense 6 2010-07-01 2010-07-01 false Assigned responsibilities. 884.2 Section 884.2... requests for return of members to the United States for delivery to civilian authorities when the request...

Balance velocities of the Greenland ice sheet

DEFF Research Database (Denmark)

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

1997-01-01

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

Parallel β-Sheet Structure of Alanine Tetrapeptide in the Solid State As Studied by Solid-State NMR Spectroscopy.

Science.gov (United States)

Asakura, Tetsuo; Horiguchi, Kumiko; Aoki, Akihiro; Tasei, Yugo; Naito, Akira

2016-09-01

The structural analysis of alanine oligopeptides is important for understanding the crystalline region in silks from spiders and wild silkworms and also the mechanism of cellular toxicity of human diseases arising from expansion in polyalanine sequences. The atomic-level structures of alanine tripeptide and tetrapeptide with antiparallel β-sheet structures (AP-Ala3 and AP-Ala4, respectively) together with alanine tripeptide with parallel β-sheet structures (P-Ala3) have been determined, but alanine tetrapeptide with a parallel β-sheet structure (P-Ala4) has not been reported yet. In this article, first, we established the preparation protocol of P-Ala4 from more stable AP-Ala4. Second, complete assignments of the (13)C, (15)N, and (1)H solid-state NMR spectra were performed with (13)C- and (15)N-labeled Ala4 samples using several solid-state NMR techniques. Then, the structural constraints were obtained, for example, the amide proton peaks of P-Ala4 in the (1)H double-quantum magic-angle spinning NMR spectrum were heavily overlapped and observed at about 7.4 ppm, which was a much higher field than that of 8.7-9.1 ppm observed for AP-Ala4, indicating that the intermolecular hydrogen-bond lengths across strands (N-H···O═C) were considerably longer for P-Ala4, that is, 2.21-2.34 Å, than those reported for AP-Ala4, that is, 1.8-1.9 Å. The structural model was proposed for P-Ala4 by NMR results and MD calculations.

[Rapid assessment of critical quality attributes of Chinese materia medica (II): strategy of NIR assignment].

Science.gov (United States)

Pei, Yan-Ling; Wu, Zhi-Sheng; Shi, Xin-Yuan; Zhou, Lu-Wei; Qiao, Yan-Jiang

2014-09-01

The present paper firstly reviewed the research progress and main methods of NIR spectral assignment coupled with our research results. Principal component analysis was focused on characteristic signal extraction to reflect spectral differences. Partial least squares method was concerned with variable selection to discover characteristic absorption band. Two-dimensional correlation spectroscopy was mainly adopted for spectral assignment. Autocorrelation peaks were obtained from spectral changes, which were disturbed by external factors, such as concentration, temperature and pressure. Density functional theory was used to calculate energy from substance structure to establish the relationship between molecular energy and spectra change. Based on the above reviewed method, taking a NIR spectral assignment of chlorogenic acid as example, a reliable spectral assignment for critical quality attributes of Chinese materia medica (CMM) was established using deuterium technology and spectral variable selection. The result demonstrated the assignment consistency according to spectral features of different concentrations of chlorogenic acid and variable selection region of online NIR model in extract process. Although spectral assignment was initial using an active pharmaceutical ingredient, it is meaningful to look forward to the futurity of the complex components in CMM. Therefore, it provided methodology for NIR spectral assignment of critical quality attributes in CMM.

Cholera Fact Sheet

Science.gov (United States)

... news-room/fact-sheets/detail/cholera","@context":"http://schema.org","@type":"Article"}; العربية 中文 français русский español ... that includes feedback at the local level and information-sharing at the global level. Cholera cases are ...

Magneto-hydrodynamics of coupled fluid–sheet interface with mass suction and blowing

International Nuclear Information System (INIS)

Ahmad, R.

2016-01-01

There are large number of studies which prescribe the kinematics of the sheet and ignore the sheet's mechanics. However, the current boundary layer analysis investigates the mechanics of both the electrically conducting fluid and a permeable sheet, which makes it distinct from the other studies in the literature. One of the objectives of the current study is to (i) examine the behaviour of magnetic field effect for both the surface and the electrically conducting fluid (ii) investigate the heat and mass transfer between a permeable sheet and the surrounding electrically conducting fluid across the hydro, thermal and mass boundary layers. Self-similar solutions are obtained by considering the RK45 technique. Analytical solution is also found for the stretching sheet case. The skin friction dual solutions are presented for various types of sheet. The influence of pertinent parameters on the dimensionless velocity, shear stress, temperature, mass concentration, heat and mass transfer rates on the fluid–sheet interface is presented graphically as well as numerically. The obtained results are of potential benefit for studying the electrically conducting flow over various soft surfaces such as synthetic plastics, soft silicone sheet and soft synthetic rubber sheet. These surfaces are easily deformed by thermal fluctuations or thermal stresses. - Highlights: • The momentum equation is modelled for both the surrounding MHD fluid and the sheet with the effects of mass suction and blowing. • The current study further investigates the heat and mass transfer characteristics between a permeable sheet and the surrounding electrically conducting fluid across the thermal and mass boundary layers. • Both the approximated and analytical techniques have been included for the purpose of comparison, and the perfect numerical agreements have been established with the previous studies. • Dual solutions for the skin friction coefficients are found for various categories of

Composite cell sheet for periodontal regeneration: crosstalk between different types of MSCs in cell sheet facilitates complex periodontal-like tissue regeneration.

Science.gov (United States)

Zhang, Hao; Liu, Shiyu; Zhu, Bin; Xu, Qiu; Ding, Yin; Jin, Yan

2016-11-14

Tissue-engineering strategies based on mesenchymal stem cells (MSCs) and cell sheets have been widely used for periodontal tissue regeneration. However, given the complexity in periodontal structure, the regeneration methods using a single species of MSC could not fulfill the requirement for periodontal regeneration. We researched the interaction between the periodontal ligament stem cells (PDLSCs) and jaw bone marrow-derived mesenchymal stem cells (JBMMSCs), and constructed a composite cell sheet comprising both of the above MSCs to regenerate complex periodontium-like structures in nude mice. Our results show that by co-culturing PDLSCs and JBMMSCs, the expressions of bone and extracellular matrix (ECM)-related genes and proteins were significantly improved in both MSCs. Further investigations showed that, compared to the cell sheet using PDLSCs or JBMMSCs, the composite stem cell sheet (CSCS), which comprises these two MSCs, expressed higher levels of bone- and ECM-related genes and proteins, and generated a composite structure more similar to the native periodontal tissue physiologically in vivo. In conclusion, our results demonstrate that the crosstalk between PDLSCs and JBMMSCs in cell sheets facilitate regeneration of complex periodontium-like structures, providing a promising new strategy for physiological and functional regeneration of periodontal tissue.

Effects of electron pressure anisotropy on current sheet configuration

Energy Technology Data Exchange (ETDEWEB)

Artemyev, A. V., E-mail: aartemyev@igpp.ucla.edu; Angelopoulos, V.; Runov, A. [Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095 (United States); Vasko, I. Y. [Space Research Institute, RAS, Moscow (Russian Federation)

2016-09-15

Recent spacecraft observations in the Earth's magnetosphere have demonstrated that the magnetotail current sheet can be supported by currents of anisotropic electron population. Strong electron currents are responsible for the formation of very thin (intense) current sheets playing the crucial role in stability of the Earth's magnetotail. We explore the properties of such thin current sheets with hot isotropic ions and cold anisotropic electrons. Decoupling of the motions of ions and electrons results in the generation of a polarization electric field. The distribution of the corresponding scalar potential is derived from the electron pressure balance and the quasi-neutrality condition. We find that electron pressure anisotropy is partially balanced by a field-aligned component of this polarization electric field. We propose a 2D model that describes a thin current sheet supported by currents of anisotropic electrons embedded in an ion-dominated current sheet. Current density profiles in our model agree well with THEMIS observations in the Earth's magnetotail.

Effects of electron pressure anisotropy on current sheet configuration

International Nuclear Information System (INIS)

Artemyev, A. V.; Angelopoulos, V.; Runov, A.; Vasko, I. Y.

2016-01-01

Recent spacecraft observations in the Earth's magnetosphere have demonstrated that the magnetotail current sheet can be supported by currents of anisotropic electron population. Strong electron currents are responsible for the formation of very thin (intense) current sheets playing the crucial role in stability of the Earth's magnetotail. We explore the properties of such thin current sheets with hot isotropic ions and cold anisotropic electrons. Decoupling of the motions of ions and electrons results in the generation of a polarization electric field. The distribution of the corresponding scalar potential is derived from the electron pressure balance and the quasi-neutrality condition. We find that electron pressure anisotropy is partially balanced by a field-aligned component of this polarization electric field. We propose a 2D model that describes a thin current sheet supported by currents of anisotropic electrons embedded in an ion-dominated current sheet. Current density profiles in our model agree well with THEMIS observations in the Earth's magnetotail.

Personnel dose assignment practices

International Nuclear Information System (INIS)

Fix, J.J.

1993-04-01

Implementation of DOE N 5480.6 Radiological Control Manual Article 511(3) requirements, to minimize the assignment of personnel dosimeters, should be done only under a broader context ensuring that capabilities are in place to monitor and record personnel exposure both for compliance and for potential litigation. As noted in NCRP Report No. 114, personnel dosimetry programs are conducted to meet four major objectives: radiation safety program control and evaluation; regulatory compliance; epidemiological research; and litigation. A change to Article 511(3) is proposed that would require that minimizing the assignment of personnel dosimeters take place only following full evaluation of overall capabilities (e.g., access control, area dosimetry, etc.) to meet the NCRP objectives

Structurally Oriented Nano-Sheets in Co Thin Films: Changing Their Anisotropic Physical Properties by Thermally-Induced Relaxation.

Science.gov (United States)

Vergara, José; Favieres, Cristina; Magén, César; de Teresa, José María; Ibarra, Manuel Ricardo; Madurga, Vicente

2017-12-05

We show how nanocrystalline Co films formed by separated oblique nano-sheets display anisotropy in their resistivity, magnetization process, surface nano-morphology and optical transmission. After performing a heat treatment at 270 °C, these anisotropies decrease. This loss has been monitored measuring the resistivity as a function of temperature. The resistivity measured parallel to the direction of the nano-sheets has been constant up to 270 °C, but it decreases when measured perpendicular to the nano-sheets. This suggests the existence of a structural relaxation, which produces the change of the Co nano-sheets during annealing. The changes in the nano-morphology and the local chemical composition of the films at the nanoscale after heating above 270 °C have been analysed by scanning transmission electron microscopy (STEM). Thus, an approach and coalescence of the nano-sheets have been directly visualized. The spectrum of activation energies of this structural relaxation has indicated that the coalescence of the nano-sheets has taken place between 1.2 and 1.7 eV. In addition, an increase in the size of the nano-crystals has occurred in the samples annealed at 400 °C. This study may be relevant for the application in devices working, for example, in the GHz range and to achieve the retention of the anisotropy of these films at higher temperatures.

Structurally Oriented Nano-Sheets in Co Thin Films: Changing Their Anisotropic Physical Properties by Thermally-Induced Relaxation

Directory of Open Access Journals (Sweden)

José Vergara

2017-12-01

Full Text Available We show how nanocrystalline Co films formed by separated oblique nano-sheets display anisotropy in their resistivity, magnetization process, surface nano-morphology and optical transmission. After performing a heat treatment at 270 °C, these anisotropies decrease. This loss has been monitored measuring the resistivity as a function of temperature. The resistivity measured parallel to the direction of the nano-sheets has been constant up to 270 °C, but it decreases when measured perpendicular to the nano-sheets. This suggests the existence of a structural relaxation, which produces the change of the Co nano-sheets during annealing. The changes in the nano-morphology and the local chemical composition of the films at the nanoscale after heating above 270 °C have been analysed by scanning transmission electron microscopy (STEM. Thus, an approach and coalescence of the nano-sheets have been directly visualized. The spectrum of activation energies of this structural relaxation has indicated that the coalescence of the nano-sheets has taken place between 1.2 and 1.7 eV. In addition, an increase in the size of the nano-crystals has occurred in the samples annealed at 400 °C. This study may be relevant for the application in devices working, for example, in the GHz range and to achieve the retention of the anisotropy of these films at higher temperatures.

Structural Biology Fact Sheet

Science.gov (United States)

... NIGMS NIGMS Home > Science Education > Structural Biology Structural Biology Tagline (Optional) Middle/Main Content Area PDF Version (688 KB) Other Fact Sheets What is structural biology? Structural biology is the study of how biological ...

Friction and lubrication modelling in sheet metal forming: Influence of lubrication amount, tool roughness and sheet coating on product quality

Science.gov (United States)

Hol, J.; Wiebenga, J. H.; Carleer, B.

2017-09-01

In the stamping of automotive parts, friction and lubrication play a key role in achieving high quality products. In the development process of new automotive parts, it is therefore crucial to accurately account for these effects in sheet metal forming simulations. This paper presents a selection of results considering friction and lubrication modelling in sheet metal forming simulations of a front fender product. For varying lubrication conditions, the front fender can either show wrinkling or fractures. The front fender is modelled using different lubrication amounts, tool roughness’s and sheet coatings to show the strong influence of friction on both part quality and the overall production stability. For this purpose, the TriboForm software is used in combination with the AutoForm software. The results demonstrate that the TriboForm software enables the simulation of friction behaviour for varying lubrication conditions, i.e. resulting in a generally applicable approach for friction characterization under industrial sheet metal forming process conditions.

The electrostatics of charged insulating sheets peeled from grounded conductors

International Nuclear Information System (INIS)

Datta, M J; Horenstein, M N

2008-01-01

The physics of a charged, insulating sheet peeled from a ground-plane conductor is examined. Contact charging is ensured by charging a sheet to 10-12 kV with corona to establish intimate electrostatic contact with the underlying conductor. The surface potential is next forced to zero by sweeping the sheet with a stainless-steel brush, and the surface recharged to a new potential between 0 and 11 kV. The sheet is then peeled from the ground plane and its residual charge density is measured. Results show that the residual charge equals the breakdown-limiting value, but its polarity depends on the surface potential acquired just prior to peeling. The results have relevance to studies of industrial webs and insulating sheets.

Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans.

Science.gov (United States)

Hawkings, Jon R; Wadham, Jemma L; Tranter, Martyn; Raiswell, Rob; Benning, Liane G; Statham, Peter J; Tedstone, Andrew; Nienow, Peter; Lee, Katherine; Telling, Jon

2014-05-21

The Greenland and Antarctic Ice Sheets cover ~ 10% of global land surface, but are rarely considered as active components of the global iron cycle. The ocean waters around both ice sheets harbour highly productive coastal ecosystems, many of which are iron limited. Measurements of iron concentrations in subglacial runoff from a large Greenland Ice Sheet catchment reveal the potential for globally significant export of labile iron fractions to the near-coastal euphotic zone. We estimate that the flux of bioavailable iron associated with glacial runoff is 0.40-2.54 Tg per year in Greenland and 0.06-0.17 Tg per year in Antarctica. Iron fluxes are dominated by a highly reactive and potentially bioavailable nanoparticulate suspended sediment fraction, similar to that identified in Antarctic icebergs. Estimates of labile iron fluxes in meltwater are comparable with aeolian dust fluxes to the oceans surrounding Greenland and Antarctica, and are similarly expected to increase in a warming climate with enhanced melting.

Computational Aspects of Assigning Agents to a Line

DEFF Research Database (Denmark)

Aziz, Haris; Hougaard, Jens Leth; Moreno-Ternero, Juan D.

2017-01-01

-egalitarian assignments. The approach relies on an algorithm which is shown to be faster than general purpose algorithms for the assignment problem. We also extend the approach to probabilistic assignments and explore the computational features of existing, as well as new, methods for this setting....

Computational aspects of assigning agents to a line

DEFF Research Database (Denmark)

Aziz, Haris; Hougaard, Jens Leth; Moreno-Ternero, Juan D.

2017-01-01

-egalitarian assignments. The approach relies on an algorithm which is shown to be faster than general purpose algorithms for the assignment problem. We also extend the approach to probabilistic assignments and explore the computational features of existing, as well as new, methods for this setting....

Behavior of protruding lateral plane graphene sheets in liquid dodecane: molecular dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Chen, Shenghui; Sun, Shuangqing, E-mail: sunshuangqing@upc.edu.cn; Li, Chunling [China University of Petroleum (East China), College of Science (China); Pittman, Charles U. [Mississippi State University, Department of Chemistry (United States); Lacy, Thomas E. [Mississippi State University, Department of Aerospace Engineering (United States); Hu, Songqing, E-mail: songqinghu@upc.edu.cn [China University of Petroleum (East China), College of Science (China); Gwaltney, Steven R. [Mississippi State University, Department of Chemistry (United States)

2016-11-15

Molecular dynamics simulations are used to investigate the behavior of two parallel graphene sheets fixed on one edge (lateral plane) in liquid dodecane. The interactions of these sheets and dodecane molecules are studied with different starting inter-sheet distances. The structure of the dodecane solvent is also analyzed. The results show that when the distance between the two graphene sheets is short (less than 6.8 Å), the sheets will expel the dodecane molecules between them and stack together. However, when the distance between two sheets is large (greater than 10.2 Å), the two sheets do not come together, and the dodecane molecules will form ordered layers in the interlayer spacing. The equilibrium distance between the graphene sheets can only take on specific discrete values (3.4, 7.8, and 12.1 Å), because only an integer number of dodecane layers forms between the two sheets. Once the graphene sheets are in contact, they remain in contact; the sheets do not separate to allow dodecane into the interlayer spacing.

Continental Ice Sheets and the Planetary Radiation Budget

NARCIS (Netherlands)

Oerlemans, J.

1980-01-01

The interaction between continental ice sheets and the planetary radiation budget is potentially important in climate-sensitivity studies. A simple ice-sheet model incorporated in an energybalance climate model provides a tool for studying this interaction in a quantitative way. Experiments in which

Best Management Practice Fact Sheet. 12, Filtering Practices

OpenAIRE

Sample, David; Barlow, Stefani

2013-01-01

This fact sheet is one of a 15-part series on urban stormwater management practices. This fact sheet discusses filtering practices, what they are, where they are used, how they work, maintenance, limitations, performance, expected costs and includes a glossary of terms.

Best Management Practice Fact Sheet. 10, Dry Swale

OpenAIRE

Sample, David; Doumar, Lia

2013-01-01

This fact sheet is one of a 15-part series on urban stormwater management practices. This fact sheet discusses dry swales, what they are, where they are used, how they work, maintenance, limitations, performance, expected costs and includes a glossary of terms.

Best Management Practice Fact Sheet. 11, Wet Swale

OpenAIRE

Sample, David; Doumar, Lia

2013-01-01

This fact sheet is one of a 15-part series on urban stormwater management practices. This fact sheet discusses wet swales, what they are, where they are used, how they work, maintenance, limitations, performance, expected costs and includes a glossary of terms.

Vortices on the string and superstring world sheets

International Nuclear Information System (INIS)

Abrikosov, A.A.; Kogan, Ya.I.

1989-01-01

The world-sheet dynamics of the first quantized string propagating in non-simply connected space is considered. Presence of the vortices on the world sheet lead to Berezinsky-Kosterlitz-Thouless(BKT) phase transition. Bosonic and superstring cases are discussed. 20 refs.; 2 figs

A Computerized Approach to Trickle-Process, Random Assignment.

Science.gov (United States)

Braucht, G. Nicholas; Reichardt, Charles S.

1993-01-01

Procedures for implementing random assignment with trickle processing and ways they can be corrupted are described. A computerized method for implementing random assignment with trickle processing is presented as a desirable alternative in many situations and a way of protecting against threats to assignment validity. (SLD)

Characterization of Platinum Nanoparticles Deposited on Functionalized Graphene Sheets

Directory of Open Access Journals (Sweden)

Yu-Chun Chiang

2015-09-01

Full Text Available Due to its special electronic and ballistic transport properties, graphene has attracted much interest from researchers. In this study, platinum (Pt nanoparticles were deposited on oxidized graphene sheets (cG. The graphene sheets were applied to overcome the corrosion problems of carbon black at operating conditions of proton exchange membrane fuel cells. To enhance the interfacial interactions between the graphene sheets and the Pt nanoparticles, the oxygen-containing functional groups were introduced onto the surface of graphene sheets. The results showed the Pt nanoparticles were uniformly dispersed on the surface of graphene sheets with a mean Pt particle size of 2.08 nm. The Pt nanoparticles deposited on graphene sheets exhibited better crystallinity and higher oxygen resistance. The metal Pt was the predominant Pt chemical state on Pt/cG (60.4%. The results from the cyclic voltammetry analysis showed the value of the electrochemical surface area (ECSA was 88 m2/g (Pt/cG, much higher than that of Pt/C (46 m2/g. The long-term test illustrated the degradation in ECSA exhibited the order of Pt/C (33% > Pt/cG (7%. The values of the utilization efficiency were calculated to be 64% for Pt/cG and 32% for Pt/C.

Battery with a microcorrugated, microthin sheet of highly porous corroded metal

Science.gov (United States)

LaFollette, Rodney M.

2005-09-27

Microthin sheet technology is disclosed by which superior batteries are constructed which, among other things, accommodate the requirements for high load rapid discharge and recharge, mandated by electric vehicle criteria. The microthin sheet technology has process and article overtones and can be used to form thin electrodes used in batteries of various kinds and types, such as spirally-wound batteries, bipolar batteries, lead acid batteries silver/zinc batteries, and others. Superior high performance battery features include: (a) minimal ionic resistance; (b) minimal electronic resistance; (c) minimal polarization resistance to both charging and discharging; (d) improved current accessibility to active material of the electrodes; (e) a high surface area to volume ratio; (f) high electrode porosity (microporosity); (g) longer life cycle; (h) superior discharge/recharge characteristics; (i) higher capacities (A.multidot.hr); and (j) high specific capacitance.

The Response of Ice Sheets to Climate Variability

Science.gov (United States)

Snow, K.; Goldberg, D. N.; Holland, P. R.; Jordan, J. R.; Arthern, R. J.; Jenkins, A.

2017-12-01

West Antarctic Ice Sheet loss is a significant contributor to sea level rise. While the ice loss is thought to be triggered by fluctuations in oceanic heat at the ice shelf bases, ice sheet response to ocean variability remains poorly understood. Using a synchronously coupled ice-ocean model permitting grounding line migration, this study evaluates the response of an ice sheet to periodic variations in ocean forcing. Resulting oscillations in grounded ice volume amplitude is shown to grow as a nonlinear function of ocean forcing period. This implies that slower oscillations in climatic forcing are disproportionately important to ice sheets. The ice shelf residence time offers a critical time scale, above which the ice response amplitude is a linear function of ocean forcing period and below which it is quadratic. These results highlight the sensitivity of West Antarctic ice streams to perturbations in heat fluxes occurring at decadal time scales.

Hibernia fact sheet

International Nuclear Information System (INIS)

Anon.

1994-01-01

This fact sheet gives details of the Hibernia oil field including its location, discovery date, oil company's interests in the project, the recoverable reserves of the two reservoirs, the production system used, capital costs of the project, and overall targets for Canadian benefit. Significant dates for the Hibernia project are listed. (UK)

Health risk among asbestos cement sheet manufacturing workers in Thailand.

Science.gov (United States)

Phanprasit, Wantanee; Sujirarat, Dusit; Chaikittiporn, Chalermchai

2009-12-01

To assess asbestos exposure and calculate the relative risks of lung cancer among asbestos cement roof sheet workers and to predict the incidence rate of lung cancer caused by asbestos in Thailand. A cross-sectional study was conducted in four asbestos cement roof factories. Both area and personal air samples were collected and analyzed employing NIOSH method # 7400 and counting rule A for all procesess and activities. The time weight average exposures were calculated for each studied task using average area concentrations of the mill and personal concentrations. Then, cumulative exposures were estimated based on the past nation-wide air sampling concentrations and those from the present study. The relative risk (RR) of lung cancer among asbestos cement sheet workers was calculated and the number of asbestos related lung cancer case was estimated. The roof fitting polishers had the highest exposure to airborne asbestos fiber (0.73 fiber/ml). The highest average area concentration was at the conveyor to the de-bagger areas (0.02 fiber/ml). The estimated cumulative exposure for the workers performed studied-tasks ranged in between 90.13-115.65 fiber-years/ml while the relative risk of lung cancer calculated using US. EPA's model were 5.37-5.96. Based on the obtained RR, lung cancer among AC sheet in Thailand would be 2 case/year. In case that AC sheet will not be prohibited from being manufactured, even though only chrysotile is allowed, the surveillance system should be further developed and more seriously implemented. The better control measures for all processes must be implemented. Furthermore, due to the environmental persistence of asbestos fiber, its life cycle analysis should be conducted in order to control environmental exposure of general population.

A simple holistic hypothesis for the self-destruction of ice sheets

Science.gov (United States)

Hughes, T.

2011-07-01

Ice sheets are the only components of Earth's climate system that can self-destruct. This paper presents the quantitative force balance for bottom-up modeling of ice sheets, as first presented qualitatively in this journal as a way to quantify ice-bed uncoupling leading to self-destruction of ice sheets ( Hughes, 2009a). Rapid changes in sea level and climate can result if a large ice-sheet self-destructs quickly, as did the former Laurentide Ice Sheet of North America between 8100 and 7900 BP, thereby terminating the last cycle of Quaternary glaciation. Ice streams discharge up to 90 percent of ice from past and present ice sheets. A hypothesis is presented in which self-destruction of an ice sheet begins when ubiquitous ice-bed decoupling, quantified as a floating fraction of ice, proceeds along ice streams. This causes ice streams to surge and reduce thickness by some 90 percent, and height above sea level by up to 99 percent for floating ice, so the ice sheet undergoes gravitational collapse. Ice collapsing over marine embayments becomes floating ice shelves that may then disintegrate rapidly. This floods the world ocean with icebergs that reduce the ocean-to-atmosphere heat exchange, thereby triggering climate change. Calving bays migrate up low stagnating ice streams and carve out the accumulation zone of the collapsed ice sheet, which prevents its recovery, decreases Earth's albedo, and terminates the glaciation cycle. This sequence of events may coincide with a proposed life cycle of ice streams that drain the ice sheet. A first-order treatment of these life cycles is presented that depends on the longitudinal force balance along the flowbands of ice streams and gives a first approximation to ice-bed uncoupling at snapshots during gravitational collapse into ice shelves that disintegrate, thereby removing the ice sheet. The stability of the Antarctic Ice Sheet is assessed using this bottom-up approach.

Fact sheet. Norwegian petroleum activity 1996

Energy Technology Data Exchange (ETDEWEB)

Westgaard, T. [ed.

1996-02-01

The present report from the Royal Ministry of Industry and Energy deals with the Norwegian petroleum activity. Main topics are as follow: Historical overview; state organisation of petroleum activities; the economic impact of Norwegian oil and gas; state revenues; mainland activities; petroleum resources; production; marketing situation for petroleum products; environmental aspects; the legal and licence framework; licensing rounds; exploration; fields in production; fields under development; discoveries with development plan under consideration; transportation systems; licence interests; company interests. 36 refs., 24 figs., 15 tabs.

Balance sheet capacity and endogenous risk

OpenAIRE

Jon Danielsson; Hyun Song Shin; Jean-Pierre Zigrand

2011-01-01

Banks operating under Value-at-Risk constraints give rise to a well-defined aggregate balance sheet capacity for the banking sector as a whole that depends on total bank capital. Equilibrium risk and market risk premiums can be solved in closed form as functions of aggregate bank capital. We explore the empirical properties of the model in light of recent experience in the financial crisis and highlight the importance of balance sheet capacity as the driver of the financial cycle and market r...

Symmetry breaking bifurcations of a current sheet

International Nuclear Information System (INIS)

Parker, R.D.; Dewar, R.L.; Johnson, J.L.

1990-01-01

Using a time evolution code with periodic boundary conditions, the viscoresistive hydromagnetic equations describing an initially static, planar current sheet with large Lundquist number have been evolved for times long enough to reach a steady state. A cosh 2 x resistivity model was used. For long periodicity lengths L p , the resistivity gradient drives flows that cause forced reconnection at X point current sheets. Using L p as a bifurcation parameter, two new symmetry breaking bifurcations were found: a transition to an asymmetric island chain with nonzero, positive, or negative phase velocity, and a transition to a static state with alternating large and small islands. These states are reached after a complex transient behavior, which involves a competition between secondary current sheet instability and coalescence

Sequence-specific 1H NMR assignments and secondary structure of the Arc repressor of bacteriophage P22, as determined by two-dimensional 1H NMR spectroscopy

International Nuclear Information System (INIS)

Breg, J.N.; Boelens, R.; George, A.V.E.; Kaptein, R.

1989-01-01

The Arc repressor of bacteriophage P22 is a DNA binding protein that does not belong to any of the known classes of such proteins. The authors have undertaken a 1 H NMR study of the protein with the aim of elucidating its three-dimensional structure in solution and its mode of binding of operator DNA. Here the authors present the 1 H nuclear magnetic resonance (NMR) assignments of all backbone protons an most of the side-chain protons of Arc repressor. Elements of secondary structure have been identified on the basis of networks of characteristics sequential and medium-range nuclear Overhauser enhancements (NOEs). Two α-helical regions have been found in the peptide regions 16-29 and 35-45. The ends of the helices could not yet be firmly established and could extend to residue 31 for the first helix and to residue 49 for the second. Immediately before the first helix, between residues 8 and 14, a region is present with β-sheet characteristics dominated by a close proximity of the α-protons of residues 9 and 13. Because of the dimeric nature of the protein there are still two possible ways in which the NOEs in the β-sheet region can be interpreted. While the data presently do not allow an unambiguous choice between these two possibilities, some evidence is discussed that favors the latter (β-sheet between monomers). Since the N-terminal region of Arc is responsible for the sequence-specific recognition of its operator, the findings suggest the existence of a DNA binding motif in which a β-sheet region is present

Tuning the mechanical properties of vertical graphene sheets through atomic layer deposition

International Nuclear Information System (INIS)

Davami, Keivan; Jiang, Yijie; Cortes, John; Lin, Chen; Turner, Kevin T; Bargatin, Igor; Shaygan, Mehrdad

2016-01-01

We report the fabrication and characterization of graphene nanostructures with mechanical properties that are tuned by conformal deposition of alumina. Vertical graphene (VG) sheets, also called carbon nanowalls (CNWs), were grown on copper foil substrates using a radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) technique and conformally coated with different thicknesses of alumina (Al_2O_3) using atomic layer deposition (ALD). Nanoindentation was used to characterize the mechanical properties of pristine and alumina-coated VG sheets. Results show a significant increase in the effective Young’s modulus of the VG sheets with increasing thickness of deposited alumina. Deposition of only a 5 nm thick alumina layer on the VG sheets nearly triples the effective Young’s modulus of the VG structures. Both energy absorption and strain recovery were lower in VG sheets coated with alumina than in pure VG sheets (for the same peak force). This may be attributed to the increase in bending stiffness of the VG sheets and the creation of connections between the sheets after ALD deposition. These results demonstrate that the mechanical properties of VG sheets can be tuned over a wide range through conformal atomic layer deposition, facilitating the use of VG sheets in applications where specific mechanical properties are needed. (paper)

Distribution of energetic oxygen and hydrogen in the near-Earth plasma sheet

Science.gov (United States)

Kronberg, E. A.; Grigorenko, E. E.; Haaland, S. E.; Daly, P. W.; Delcourt, D. C.; Luo, H.; Kistler, L. M.; Dandouras, I.

2015-05-01

The spatial distributions of different ion species are useful indicators for plasma sheet dynamics. In this statistical study based on 7 years of Cluster observations, we establish the spatial distributions of oxygen ions and protons at energies from 274 to 955 keV, depending on geomagnetic and solar wind (SW) conditions. Compared with protons, the distribution of energetic oxygen has stronger dawn-dusk asymmetry in response to changes in the geomagnetic activity. When the interplanetary magnetic field (IMF) is directed southward, the oxygen ions show significant acceleration in the tail plasma sheet. Changes in the SW dynamic pressure (Pdyn) affect the oxygen and proton intensities in the same way. The energetic protons show significant intensity increases at the near-Earth duskside during disturbed geomagnetic conditions, enhanced SW Pdyn, and southward IMF, implying there location of effective inductive acceleration mechanisms and a strong duskward drift due to the increase of the magnetic field gradient in the near-Earth tail. Higher losses of energetic ions are observed in the dayside plasma sheet under disturbed geomagnetic conditions and enhanced SW Pdyn. These observations are in agreement with theoretical models.

Modelling the Antarctic Ice Sheet

DEFF Research Database (Denmark)

Pedersen, Jens Olaf Pepke; Holm, A.

2015-01-01

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

Detecting Plagiarism in MS Access Assignments

Science.gov (United States)

Singh, Anil

2013-01-01

Assurance of individual effort from students in computer-based assignments is a challenge. Due to digitization, students can easily use a copy of their friend's work and submit it as their own. Plagiarism in assignments puts students who cheat at par with those who work honestly and this compromises the learning evaluation process. Using a…

Silicon Sheet Quality is Improved By Meniscus Control

Science.gov (United States)

Yates, D. A.; Hatch, A. E.; Goldsmith, J. M.

1983-01-01

Better quality silicon crystals for solar cells are possible with instrument that monitors position of meniscus as sheet of solid silicon is drawn from melt. Using information on meniscus height, instrument generates feedback signal to control melt temperature. Automatic control ensures more uniform silicon sheets.

Oscillations of spherical fullerenes interacting with graphene sheet

Energy Technology Data Exchange (ETDEWEB)

Ghavanloo, Esmaeal, E-mail: ghavanloo@shirazu.ac.ir; Fazelzadeh, S. Ahmad

2017-01-01

In the present study, the oscillations of spherical fullerenes in the vicinity of a fully constrained graphene sheet are investigated. Using the continuous approximation and Lennard-Jones potential, the van der Waals (vdW) potential energy and interaction forces are obtained. The equation of motion is derived and directly solved based on the actual force distribution between the fullerene molecules and the graphene sheet. Numerical results are obtained and shown that the oscillation is sensitive to the size of the fullerene as well as the distance between the center of the fullerene and the graphene sheet.

Magma transport in sheet intrusions of the Alnö carbonatite complex, central Sweden.

Science.gov (United States)

Andersson, Magnus; Almqvist, Bjarne S G; Burchardt, Steffi; Troll, Valentin R; Malehmir, Alireza; Snowball, Ian; Kübler, Lutz

2016-06-10

Magma transport through the Earth's crust occurs dominantly via sheet intrusions, such as dykes and cone-sheets, and is fundamental to crustal evolution, volcanic eruptions and geochemical element cycling. However, reliable methods to reconstruct flow direction in solidified sheet intrusions have proved elusive. Anisotropy of magnetic susceptibility (AMS) in magmatic sheets is often interpreted as primary magma flow, but magnetic fabrics can be modified by post-emplacement processes, making interpretation of AMS data ambiguous. Here we present AMS data from cone-sheets in the Alnö carbonatite complex, central Sweden. We discuss six scenarios of syn- and post-emplacement processes that can modify AMS fabrics and offer a conceptual framework for systematic interpretation of magma movements in sheet intrusions. The AMS fabrics in the Alnö cone-sheets are dominantly oblate with magnetic foliations parallel to sheet orientations. These fabrics may result from primary lateral flow or from sheet closure at the terminal stage of magma transport. As the cone-sheets are discontinuous along their strike direction, sheet closure is the most probable process to explain the observed AMS fabrics. We argue that these fabrics may be common to cone-sheets and an integrated geology, petrology and AMS approach can be used to distinguish them from primary flow fabrics.

Localized fast flow disturbance observed in the plasma sheet and in the ionosphere

Directory of Open Access Journals (Sweden)

R. Nakamura

2005-02-01

Full Text Available An isolated plasma sheet flow burst took place at 22:02 UT, 1 September 2002, when the Cluster footpoint was located within the area covered by the Magnetometers-Ionospheric Radars-All-sky Cameras Large Experiment (MIRACLE. The event was associated with a clear but weak ionospheric disturbance and took place during a steady southward IMF interval, about 1h preceding a major substorm onset. Multipoint observations, both in space and from the ground, allow us to discuss the temporal and spatial scale of the disturbance both in the magnetosphere and ionosphere. Based on measurements from four Cluster spacecraft it is inferred that Cluster observed the dusk side part of a localized flow channel in the plasma sheet with a flow shear at the front, suggesting a field-aligned current out from the ionosphere. In the ionosphere the equivalent current pattern and possible field-aligned current location show a pattern similar to the auroral streamers previously obtained during an active period, except for its spatial scale and amplitude. It is inferred that the footpoint of Cluster was located in the region of an upward field-aligned current, consistent with the magnetospheric observations. The entire disturbance in the ionosphere lasted about 10min, consistent with the time scale of the current sheet disturbance in the magnetosphere. The plasma sheet bulk flow, on the other hand, had a time scale of about 2min, corresponding to the time scale of an equatorward excursion of the enhanced electrojet. These observations confirm that localized enhanced convection in the magnetosphere and associated changes in the current sheet structure produce a signature with consistent temporal and spatial scale at the conjugate ionosphere.

Should Cheat Sheets be Used as Study Aids in Economics Tests?

OpenAIRE

Yoav Wachsman

2002-01-01

This paper reports an experiment that investigates the effectiveness of cheat sheets as study aids for economics tests. A cheat sheet is a piece of paper that students can write anything they want on and use during a test. I find that both preparing and using a cheat sheet improves students' test performance. Additionally, there is no evidence that students become over dependent on their cheat sheets for answers.

Bamboo Fibre Reinforced Cement Used as a Roofing Sheet | Alade ...

African Journals Online (AJOL)

Bamboo fibre roofing sheet was able to withstand an average load of 51Kg, which is above the minimum required strength of 50kg. Comparatively, Asbestos roofing sheets and coconut fibre roofing sheets of similar dimensions had failure loads of 104.65Kg and 79Kg respectively. When immersed in water, bamboo fibre ...

Evidence of β-sheet structure induced kinetic stability of papain upon thermal and sodium dodecyl sulphate denaturation

Directory of Open Access Journals (Sweden)

Rašković Brankica

2015-01-01

Full Text Available Papain is a protease that consists of α-helical and β-sheet domains which unfold almost independently. Both, papain considerable thermal stability and sodium dodecyl sulphate (SDS resistance have been shown. However, the ability of each domain to unfold upon thermal and SDS denaturation has never been studied. This work shows that fruit papain has slightly higher thermal inactivation resistance when it is compared to stem papain with rather high activation energy (Ea of 223 ± 16 kJmol-1 and Tm50 value of 79 ± 2 °C. SDS resistance of fruit papain was estimated by SDS-PAGE analysis and activity staining. It has been noted that, in the presence of SDS, unless heat energy was applied in order to unfold papain, the protein remained active. Furthermore, it has been proven via Fourier transform infrared spectroscopy (FT-IR that α-helical domain of fruit papain is more prone to unfolding at elevated temperatures and in the presence of SDS then β-sheet rich domain. Thermal denaturation of papain without detergent present led to accelerated formation of aggregation specific intermolecular β-sheets as compared to native protein. Presented results are both, of fundamental and application importance. [Projekat Ministarstva nauke Republike Srbije, br. 172049

Solar wind and substorm excitation of the wavy current sheet

Directory of Open Access Journals (Sweden)

C. Forsyth

2009-06-01

Full Text Available Following a solar wind pressure pulse on 3 August 2001, GOES 8, GOES 10, Cluster and Polar observed dipolarizations of the magnetic field, accompanied by an eastward expansion of the aurora observed by IMAGE, indicating the occurrence of two substorms. Prior to the first substorm, the motion of the plasma sheet with respect to Cluster was in the ZGSM direction. Observations following the substorms show the occurrence of current sheet waves moving predominantly in the −YGSM direction. Following the second substorm, the current sheet waves caused multiple current sheet crossings of the Cluster spacecraft, previously studied by Zhang et al. (2002. We further this study to show that the velocity of the current sheet waves was similar to the expansion velocity of the substorm aurora and the expansion of the dipolarization regions in the magnetotail. Furthermore, we compare these results with the current sheet wave models of Golovchanskaya and Maltsev (2005 and Erkaev et al. (2008. We find that the Erkaev et al. (2008 model gives the best fit to the observations.

Tearing resistance of some co-polyester sheets

International Nuclear Information System (INIS)

Kim, Ho Sung; Karger-Kocsis, Jozsef

2004-01-01

A three-zone model consisting of initial, evolutionary and stabilised plastic zones for tearing resistance was proposed for polymer sheets. An analysis with the model, based on the essential work of fracture (EWF) approach, was demonstrated to be capable for predicting specific total work of fracture along the tear path across all the plastic zones although accuracy of specific essential work of fracture is subject to improvement. Photo-elastic images were used for identification of plastic deformation sizes and profiles. Fracture mode change during loading was described in relation with the three zones. Tearing fracture behaviour of extruded mono- and bi-layer sheets of different types of amorphous co-polyesters and different thicknesses was investigated. Thick material exhibited higher specific total work of tear fracture than thin mono-layer sheet in the case of amorphous polyethylene terephthalate (PET). This finding was explained in terms of plastic zone size formed along the tear path, i.e., thick material underwent larger plastic deformation than thin material. When PET and polyethylene terephthalate glycol (PETG) were laminated with each other, specific total work of fracture of the bi-layer sheets was not noticeably improved over that of the constituent materials

Contextual effects on perceived contrast: figure-ground assignment and orientation contrast.

Science.gov (United States)

Self, Matthew W; Mookhoek, Aart; Tjalma, Nienke; Roelfsema, Pieter R

2015-02-02

Figure-ground segregation is an important step in the path leading to object recognition. The visual system segregates objects ('figures') in the visual scene from their backgrounds ('ground'). Electrophysiological studies in awake-behaving monkeys have demonstrated that neurons in early visual areas increase their firing rate when responding to a figure compared to responding to the background. We hypothesized that similar changes in neural firing would take place in early visual areas of the human visual system, leading to changes in the perception of low-level visual features. In this study, we investigated whether contrast perception is affected by figure-ground assignment using stimuli similar to those in the electrophysiological studies in monkeys. We measured contrast discrimination thresholds and perceived contrast for Gabor probes placed on figures or the background and found that the perceived contrast of the probe was increased when it was placed on a figure. Furthermore, we tested how this effect compared with the well-known effect of orientation contrast on perceived contrast. We found that figure-ground assignment and orientation contrast produced changes in perceived contrast of a similar magnitude, and that they interacted. Our results demonstrate that figure-ground assignment influences perceived contrast, consistent with an effect of figure-ground assignment on activity in early visual areas of the human visual system. © 2015 ARVO.

Annual Energy Balance Sheets 2001-2002

International Nuclear Information System (INIS)

2004-01-01

During the year 2002 the primary supply of energy reached 629 TWh, which is 7.7 TWh less than 2001. The decrease originates mainly from the reduced electricity production from water power. Also the electricity production in nuclear power plants decreased by 4.5 TWh. If we were to look at the supplied energy for final consumption we will find a slightly rise by 1.8 TWh. The year 2002 was warmer than a 'normal' year and that consequently brings lower energy needs. Compared with 2001, 2002 was not warmer and a net electricity import of 5.4 TWh covered the energy needs. The energy use increased by 3.3 TWh between 2002 and 2001. The industry sector shows the largest rise by 2.9 TWh, nearly 2 per cent. Within that sector, energy from biomass fuel had a rise by 6.7 per cent. The household sector decreases its energy use by 2.7 per cent, and oil and electricity show the largest decrease. The proportionately high electricity price probably had a slowing down effect on the electricity use. The balance sheets of energy sources are showing the total supply and consumption of energy sources expressed in original units, i.e. units recorded in the primary statistics - mainly commercial units. The production of derived energy commodities is recorded on the supply - side of the balance sheets of energy sources, which is not the case in the energy balance sheets. The balance sheets of energy sources also include specifications of input--output and energy consumption in energy conversion industries. The energy balance sheets are based on primary data recorded in the balance sheets of energy sources, here expressed in a common energy unit, TJ. The production of derived energy is recorded in a second flow-step comprising energy turnover in energy conversion and is also specified in complementary input - output tables for energy conversion industries. The following items are shown in the energy balance sheets. 1.1 Inland supply of primary energy; 1.3 Import; 1.4 Export; 1.5 Changes in

Hypsometric amplification and routing moderation of Greenland ice sheet meltwater release

Science.gov (United States)

van As, Dirk; Mikkelsen, Andreas Bech; Holtegaard Nielsen, Morten; Box, Jason E.; Claesson Liljedahl, Lillemor; Lindbäck, Katrin; Pitcher, Lincoln; Hasholt, Bent

2017-06-01

Concurrent ice sheet surface runoff and proglacial discharge monitoring are essential for understanding Greenland ice sheet meltwater release. We use an updated, well-constrained river discharge time series from the Watson River in southwest Greenland, with an accurate, observation-based ice sheet surface mass balance model of the ˜ 12 000 km2 ice sheet area feeding the river. For the 2006-2015 decade, we find a large range of a factor of 3 in interannual variability in discharge. The amount of discharge is amplified ˜ 56 % by the ice sheet's hypsometry, i.e., area increase with elevation. A good match between river discharge and ice sheet surface meltwater production is found after introducing elevation-dependent transit delays that moderate diurnal variability in meltwater release by a factor of 10-20. The routing lag time increases with ice sheet elevation and attains values in excess of 1 week for the upper reaches of the runoff area at ˜ 1800 m above sea level. These multi-day routing delays ensure that the highest proglacial discharge levels and thus overbank flooding events are more likely to occur after multi-day melt episodes. Finally, for the Watson River ice sheet catchment, we find no evidence of meltwater storage in or release from the en- and subglacial environments in quantities exceeding our methodological uncertainty, based on the good match between ice sheet runoff and proglacial discharge.

Promoting Discussion in Peer Instruction: Discussion Partner Assignment and Accountability Scoring Mechanisms

Science.gov (United States)

Chou, Chih-Yueh; Lin, Pin-Hsun

2015-01-01

Peer instruction (PI) involves students answering questions and peer discussion learning activities. PI can enhance student performance and engagement in classroom instruction. However, some students do not engage in the discussions. This study proposes two mechanisms, discussion partner assignment and accountability scoring mechanisms, to form…

Tensile property improvement of TWIP-cored three-layer steel sheets fabricated by hot-roll-bonding with low-carbon steel or interstitial-free steel

Science.gov (United States)

Park, Jaeyeong; Kim, Jung-Su; Kang, Minju; Sohn, Seok Su; Cho, Won Tae; Kim, Hyoung Seop; Lee, Sunghak

2017-01-01

TWIP-cored three-layer steel sheets were newly fabricated by hot rolling of TWIP steel sheet surrounded by low-carbon (LC) or interstitial-free (IF) steel sheets. TWIP/LC or TWIP/IF interfaces were well bonded without pores or voids, while a few pearlites were thinly formed along the interfaces. The strengths and elongation of the TWIP-cored sheets increased as the volume fraction of TWIP-cored region increased, and were also well matched with the ones calculated by a rule of mixtures based on volume fraction or force fraction. According to digital image correlation and electron back-scatter diffraction analyses, very high strain hardening effect in the initial deformation stage and active twin formation in the interfacial region beneficially affected the overall homogeneous deformation in the TWIP-cored sheets without any yield point phenomenon occurring in the LC sheet and serrations occurring in the TWIP sheet, respectively. These TWIP-cored sheets can cover a wide range of yield strength, tensile strength, and ductility levels, e.g., 320~498 MPa, 545~878 MPa, and 48~54%, respectively, by controlling the volume fraction of TWIP-cored region, and thus present new applications to multi-functional automotive steel sheets requiring excellent properties.

A Post-Final Assignment for the Methods Course: Providing an Incentive to Professional Growth for Future Teachers.

Science.gov (United States)

Bentley, Michael L.

This paper describes J. Rosengren's post-final assignment and M. Harmin's truth signs activity that were incorporated into a secondary science methods course for preservice teachers. The strength of the post-final assignment is that it is a strategy for extending student learning past the end of a course and even beyond the initial teaching…

Financing gas plants using off balance sheet structures

International Nuclear Information System (INIS)

Best, R.J.; Malcolm, V.

1999-01-01

A means by which to finance oil and gas facilities using off balance sheet structures was presented. Off balance sheet facility financing means the sale by an oil and gas producer of a processing and/or transportation facility to a financial intermediary, who under a Management Agreement, appoints the producer as the operator of the facility. The financial intermediary charges a fixed processing fee to the producer and all the benefits and upside of ownership are retained by the producer. This paper deals specifically with a flexible off balance sheet facility financing structure that can be used to make effective use of discretionary capital which is committed to gas processing and to the construction of new gas processing facilities. Off balance sheet financing is an attractive alternative method of ownership that frees up capital that is locked into the facilities while allowing the producer to retain strategic control of the processing facility

Fast imaging of live organisms with sculpted light sheets

Science.gov (United States)

Chmielewski, Aleksander K.; Kyrsting, Anders; Mahou, Pierre; Wayland, Matthew T.; Muresan, Leila; Evers, Jan Felix; Kaminski, Clemens F.

2015-04-01

Light-sheet microscopy is an increasingly popular technique in the life sciences due to its fast 3D imaging capability of fluorescent samples with low photo toxicity compared to confocal methods. In this work we present a new, fast, flexible and simple to implement method to optimize the illumination light-sheet to the requirement at hand. A telescope composed of two electrically tuneable lenses enables us to define thickness and position of the light-sheet independently but accurately within milliseconds, and therefore optimize image quality of the features of interest interactively. We demonstrated the practical benefit of this technique by 1) assembling large field of views from tiled single exposure each with individually optimized illumination settings; 2) sculpting the light-sheet to trace complex sample shapes within single exposures. This technique proved compatible with confocal line scanning detection, further improving image contrast and resolution. Finally, we determined the effect of light-sheet optimization in the context of scattering tissue, devising procedures for balancing image quality, field of view and acquisition speed.

Heat Exchanger Tube to Tube Sheet Joints Corrosion Behavior

Directory of Open Access Journals (Sweden)

M. Iancu

2013-03-01

Full Text Available Paper presents the studies made by the authors above the tube to tube sheet fittings of heat exchanger with fixed covers from hydrofining oil reforming unit. Tube fittings are critical zones for heat exchangers failures. On a device made from material tube and tube sheet at real joints dimensions were establish axial compression force and traction force at which tube is extracted from expanded joint. Were used two shapes joints with two types of fittings surfaces, one with smooth hole of tube sheet and other in which on boring surface we made a groove. From extracted expanded tube zones were made samples for corrosion tests in order to establish the corrosion rate, corrosion potential and corrosion current in working mediums such as hydrofining oil and industrial water at different temperatures. The corrosion rate values and the temperature influence are important to evaluate joints durability and also the results obtained shows that the boring tube sheet shape with a groove on hole tube shape presents a better corrosion behavior then the shape with smooth hole tube sheet.

Interaction of a charge with a thin plasma sheet

International Nuclear Information System (INIS)

Bordag, M.

2007-01-01

The interaction of the electromagnetic field with a two-dimensional plasma sheet intended to describe the pi-electrons of a carbon nanotube or a C 60 molecule is investigated. By first integrating out the displacement field of the plasma or the electromagnetic field, different representations for quantities like the Casimir energy are derived which are shown to be consistent with one another. Starting from the covariant gauge for the electromagnetic field, it is shown that the matching conditions to which the presence of the plasma sheet can be reduced are different from the commonly used ones. The difference in the treatments does not show up in the Casimir force between two parallel sheets, but it is present in the Casimir-Polder force between a charge or a neutral atom and a sheet. At once, since the plasma sheet is a regularization of the conductor boundary conditions, this sheds light on the difference in physics found earlier in the realization of conductor boundary conditions as 'thin' or 'thick' boundary conditions in Phys. Rev. D 70, 085010 (2004)

A Case Study and Balance Sheet Approach to Unemployment.

Science.gov (United States)

Hesketh, Beryl; And Others

1987-01-01

Describes positive and negative aspects of employment and unemployment in a balance sheet framework. Discusses the value of the balance sheet approach in understanding individual differences in reactions to unemployment. (Author/KS)

The Potsdam Parallel Ice Sheet Model (PISM-PIK – Part 2: Dynamic equilibrium simulation of the Antarctic ice sheet

Directory of Open Access Journals (Sweden)

M. A. Martin

2011-09-01

Full Text Available We present a dynamic equilibrium simulation of the ice sheet-shelf system on Antarctica with the Potsdam Parallel Ice Sheet Model (PISM-PIK. The simulation is initialized with present-day conditions for bed topography and ice thickness and then run to steady state with constant present-day surface mass balance. Surface temperature and sub-shelf basal melt distribution are parameterized. Grounding lines and calving fronts are free to evolve, and their modeled equilibrium state is compared to observational data. A physically-motivated calving law based on horizontal spreading rates allows for realistic calving fronts for various types of shelves. Steady-state dynamics including surface velocity and ice flux are analyzed for whole Antarctica and the Ronne-Filchner and Ross ice shelf areas in particular. The results show that the different flow regimes in sheet and shelves, and the transition zone between them, are captured reasonably well, supporting the approach of superposition of SIA and SSA for the representation of fast motion of grounded ice. This approach also leads to a natural emergence of sliding-dominated flow in stream-like features in this new 3-D marine ice sheet model.

BRITICE-CHRONO: Constraining rates and style of marine-influenced ice sheet decay to provide a data-rich playground for ice sheet modellers

Science.gov (United States)

Clark, Chris

2014-05-01

Uncertainty exists regarding the fate of the Antarctic and Greenland ice sheets and how they will respond to forcings from sea level and atmospheric and ocean temperatures. If we want to know more about the mechanisms and rate of change of shrinking ice sheets, then why not examine an ice sheet that has fully disappeared and track its retreat through time? If achieved in enough detail such information could become a data-rich playground for improving the next breed of numerical ice sheet models to be used in ice and sea level forecasting. We regard that the last British-Irish Ice Sheet is a good target for this work, on account of its small size, density of information and with its numerous researchers already investigating it. BRITICE-CHRONO is a large (>45 researchers) NERC-funded consortium project comprising Quaternary scientists and glaciologists who will search the seafloor around Britain and Ireland and parts of the landmass in order to find and extract samples of sand, rock and organic matter that can be dated (OSL; Cosmogenic; 14C) to reveal the timing and rate of change of the collapsing British-Irish Ice Sheet. The purpose is to produce a high resolution dataset on the demise on an ice sheet - from the continental shelf edge and across the marine to terrestrial transition. Some 800 new date assessments will be added to those that already exist. This poster reports on the hypotheses that underpin the work. Data on retreat will be collected by focusing on 8 transects running from the continental shelf edge to a short distance (10s km) onshore and acquiring marine and terrestrial samples for geochronometric dating. The project includes funding for 587 radiocarbon, 140 OSL and 158 TCN samples for surface exposure dating; with sampling accomplished by two research cruises and 16 fieldwork campaigns. Results will reveal the timing and rate of change of ice margin recession for each transect, and combined with existing landform and dating databases, will be

Mountain building and the initiation of the Greenland Ice Sheet

DEFF Research Database (Denmark)

Solgaard, Anne Munck; Bonow, Johan; Langen, Peter Lang

2013-01-01

The effects of a new hypothesis about mountain building in Greenland on ice sheet initiation are investigated using an ice sheet model in combination with a climate model. According to this hypothesis, low-relief landscapes near sea level characterised Greenland in Miocene times until two phases...... superimposed by cold and warm excursions. The modelling results show that no ice initiates in the case of the low-lying and almost flat topography prior to the uplifts. However, the results demonstrate a significant ice sheet growth in response to the orographically induced increase in precipitation....... Under conditions that are colder than the present, the ice can overcome the Föhn effect, flow into the interior and form a coherent ice sheet. The results thus indicate that the Greenland Ice Sheet of today is a relict formed under colder conditions. The modelling results are consistent...

Two-and-one-half-dimensional magnetohydrodynamic simulations of the plasma sheet in the presence of oxygen ions: The plasma sheet oscillation and compressional Pc 5 waves

International Nuclear Information System (INIS)

Lu Li; Liu Zhenxing; Cao Jinbin

2002-01-01

Two-and-one-half-dimensional magnetohydrodynamic simulations of the multicomponent plasma sheet with the velocity curl term in the magnetic equation are represented. The simulation results can be summarized as follows: (1) There is an oscillation of the plasma sheet with the period on the order of 400 s (Pc 5 range); (2) the magnetic equator is a node of the magnetic field disturbance; (3) the magnetic energy integral varies antiphase with the internal energy integral; (4) disturbed waves have a propagating speed on the order of 10 km/s earthward; (5) the abundance of oxygen ions influences amplitude, period, and dissipation of the plasma sheet oscillation. It is suggested that the compressional Pc 5 waves, which are observed in the plasma sheet close to the magnetic equator, may be caused by the plasma sheet oscillation, or may be generated from the resonance of the plasma sheet oscillation with some Pc 5 perturbation waves coming from the outer magnetosphere

Mirage effect from thermally modulated transparent carbon nanotube sheets.

Science.gov (United States)

Aliev, Ali E; Gartstein, Yuri N; Baughman, Ray H

2011-10-28

The single-beam mirage effect, also known as photothermal deflection, is studied using a free-standing, highly aligned carbon nanotube aerogel sheet as the heat source. The extremely low thermal capacitance and high heat transfer ability of these transparent forest-drawn carbon nanotube sheets enables high frequency modulation of sheet temperature over an enormous temperature range, thereby providing a sharp, rapidly changing gradient of refractive index in the surrounding liquid or gas. The advantages of temperature modulation using carbon nanotube sheets are multiple: in inert gases the temperature can reach > 2500 K; the obtained frequency range for photothermal modulation is ~100 kHz in gases and over 100 Hz in high refractive index liquids; and the heat source is transparent for optical and acoustical waves. Unlike for conventional heat sources for photothermal deflection, the intensity and phase of the thermally modulated beam component linearly depends upon the beam-to-sheet separation over a wide range of distances. This aspect enables convenient measurements of accurate values for thermal diffusivity and the temperature dependence of refractive index for both liquids and gases. The remarkable performance of nanotube sheets suggests possible applications as photo-deflectors and for switchable invisibility cloaks, and provides useful insights into their use as thermoacoustic projectors and sonar. Visibility cloaking is demonstrated in a liquid.

Symmetry breaking bifurcations of a current sheet

International Nuclear Information System (INIS)

Parker, R.D.; Dewar, R.L.; Johnson, J.L.

1988-08-01

Using a time evolution code with periodic boundary conditions, the viscoresistive hydromagnetic equations describing an initially static, planar current sheet with large Lundquist number have been evolved for times long enough to reach a steady state. A cosh 2 x resistivity model was used. For long periodicity lengths, L p , the resistivity gradient drives flows which cause forced reconnection at X point current sheets. Using L p as a bifurcation parameter, two new symmetry breaking bifurcations were found - a transition to an asymmetric island chain with nonzero, positive or negative phase velocity, and a transition to a static state with alternating large and small islands. These states are reached after a complex transient behavior which involves a competition between secondary current sheet instability and coalescence. 31 refs., 6 figs

Flat-plate solar array project. Volume 3: Silicon sheet: Wafers and ribbons

Science.gov (United States)

Briglio, A.; Dumas, K.; Leipold, M.; Morrison, A.

1986-01-01

The primary objective of the Silicon Sheet Task of the Flat-Plate Solar Array (FSA) Project was the development of one or more low cost technologies for producing silicon sheet suitable for processing into cost-competitive solar cells. Silicon sheet refers to high purity crystalline silicon of size and thickness for fabrication into solar cells. Areas covered in the project were ingot growth and casting, wafering, ribbon growth, and other sheet technologies. The task made and fostered significant improvements in silicon sheet including processing of both ingot and ribbon technologies. An additional important outcome was the vastly improved understanding of the characteristics associated with high quality sheet, and the control of the parameters required for higher efficiency solar cells. Although significant sheet cost reductions were made, the technology advancements required to meet the task cost goals were not achieved.

Flexible taxonomic assignment of ambiguous sequencing reads

Directory of Open Access Journals (Sweden)

Jansson Jesper

2011-01-01

Full Text Available Abstract Background To characterize the diversity of bacterial populations in metagenomic studies, sequencing reads need to be accurately assigned to taxonomic units in a given reference taxonomy. Reads that cannot be reliably assigned to a unique leaf in the taxonomy (ambiguous reads are typically assigned to the lowest common ancestor of the set of species that match it. This introduces a potentially severe error in the estimation of bacteria present in the sample due to false positives, since all species in the subtree rooted at the ancestor are implicitly assigned to the read even though many of them may not match it. Results We present a method that maps each read to a node in the taxonomy that minimizes a penalty score while balancing the relevance of precision and recall in the assignment through a parameter q. This mapping can be obtained in time linear in the number of matching sequences, because LCA queries to the reference taxonomy take constant time. When applied to six different metagenomic datasets, our algorithm produces different taxonomic distributions depending on whether coverage or precision is maximized. Including information on the quality of the reads reduces the number of unassigned reads but increases the number of ambiguous reads, stressing the relevance of our method. Finally, two measures of performance are described and results with a set of artificially generated datasets are discussed. Conclusions The assignment strategy of sequencing reads introduced in this paper is a versatile and a quick method to study bacterial communities. The bacterial composition of the analyzed samples can vary significantly depending on how ambiguous reads are assigned depending on the value of the q parameter. Validation of our results in an artificial dataset confirm that a combination of values of q produces the most accurate results.

First Trimester Fetal Gender Assignment by Ultrasound

Directory of Open Access Journals (Sweden)

Sabahattin Altunyurt

2010-03-01

Full Text Available Objective: To investigate the efficiency of genital tubercule angle on detecting fetal gender in first trimester by ultrasonography. Material-Method: Fetal sex assignment by ultrasound was carried out in 172 pregnancies at 11-13+6 weeks between 2007 June and 2007 December. Gestational age was determined by the measurement of crown-rump length (CRL. The ultrasound predictions were compared with actual sex at birth. Mid-sagittal planes of a section of the fetal genital tubercle were performed to identify the gender. Results: 155 of 172 patients’ data were achieved. The overall success rate was 92.3 % in sonographic assignment of fetal sex. The correct assignment rate in female fetuses was significantly higher than males (95.9 % - 88.8 % [p=0,001]. The correct identification of fetal sex improved with advancing gestational age from 89.3 % between 11-11+6 weeks, 92.5 % between 12-12+6 weeks and 93.4 % between 13-13+6 weeks (p=0,96. Conclusion: The fetal sex assignment by ultrasonography between 11-13+6 weeks had high success rate. The sensitivity of fetal sex assignment was not affected with fetus position and gestational age.

Machine Shop Suggested Job and Task Sheets. Part I. 25 Elementary Jobs.

Science.gov (United States)

Texas A and M Univ., College Station. Vocational Instructional Services.

This volume consists of elementary job and task sheets adaptable for use in the regular vocational industrial education programs for the training of machinists and machine shop operators. Twenty-five simple machine shop job sheets are included. Some or all of this material is provided for each job sheet: an introductory sheet with aim, checking…

Current state and future perspectives on coupled ice-sheet - sea-level modelling

Science.gov (United States)

de Boer, Bas; Stocchi, Paolo; Whitehouse, Pippa L.; van de Wal, Roderik S. W.

2017-08-01

The interaction between ice-sheet growth and retreat and sea-level change has been an established field of research for many years. However, recent advances in numerical modelling have shed new light on the precise interaction of marine ice sheets with the change in near-field sea level, and the related stability of the grounding line position. Studies using fully coupled ice-sheet - sea-level models have shown that accounting for gravitationally self-consistent sea-level change will act to slow down the retreat and advance of marine ice-sheet grounding lines. Moreover, by simultaneously solving the 'sea-level equation' and modelling ice-sheet flow, coupled models provide a global field of relative sea-level change that is consistent with dynamic changes in ice-sheet extent. In this paper we present an overview of recent advances, possible caveats, methodologies and challenges involved in coupled ice-sheet - sea-level modelling. We conclude by presenting a first-order comparison between a suite of relative sea-level data and output from a coupled ice-sheet - sea-level model.

On the structure of the magnetotail current sheet

International Nuclear Information System (INIS)

Ashour-Abdalla, M.; Peroomian, V.; Richard, R.L.; Zelenyi, L.M.

1993-01-01

Results from modeling ion distribution functions in a two-dimensional reduction of the Tsyganenko magnetic field model have enabled the authors to calculate the full ion pressure tensor inside the model magnetotail. A thin current sheet is formed in the distant tail and the pressure tensor within this sheet has significant off-diagonal terms. These terms resulting from quasiadiabatic ion trajectories create azimuthally asymmetric distribution functions which are capable of maintaining stress-balance. Outside the current sheet the off-diagonal terms disappear and moderate anisotropy builds up with P perpendicular/P parallel ∼ 0.8. Closer to the Earth rapid isotropization of the distribution occurs

Greenland Ice Sheet Surface Temperature, Melt, and Mass Loss: 2000-2006

Science.gov (United States)

Hall, Dorothy K.; Williams, Richard S., Jr.; Luthcke, Scott B.; DiGirolamo, Nocolo

2007-01-01

Extensive melt on the Greenland Ice Sheet has been documented by a variety of ground and satellite measurements in recent years. If the well-documented warming continues in the Arctic, melting of the Greenland Ice Sheet will likely accelerate, contributing to sea-level rise. Modeling studies indicate that an annual or summer temperature rise of 1 C on the ice sheet will increase melt by 20-50% therefore, surface temperature is one of the most important ice-sheet parameters to study for analysis of changes in the mass balance of the ice-sheet. The Greenland Ice Sheet contains enough water to produce a rise in eustatic sea level of up to 7.0 m if the ice were to melt completely. However, even small changes (centimeters) in sea level would cause important economic and societal consequences in the world's major coastal cities thus it is extremely important to monitor changes in the ice-sheet surface temperature and to ultimately quantify these changes in terms of amount of sea-level rise. We have compiled a high-resolution, daily time series of surface temperature of the Greenland Ice Sheet, using the I-km resolution, clear-sky land-surface temperature (LST) standard product from the Moderate-Resolution Imaging Spectroradiometer (MODIS), from 2000 - 2006. We also use Gravity Recovery and Climate Experiment (GRACE) data, averaged over 10-day periods, to measure change in mass of the ice sheet as it melt and snow accumulates. Surface temperature can be used to determine frequency of surface melt, timing of the start and the end of the melt season, and duration of melt. In conjunction with GRACE data, it can also be used to analyze timing of ice-sheet mass loss and gain.

Research Status on the Heterogeneous Sheet Connection Forming Technology

Directory of Open Access Journals (Sweden)

SHI Wen-yong

2017-04-01

Full Text Available The heterogeneous sheet connection forming is one of the effective ways to realize lightweight in many fields，such as equipment manufacturing and transportation. However, there are obvious differences in the material properties，when using the traditional connection methods，there is a certain technical bottlenecks. In this paper, the technological characteristics and research status of the welding method and mechanical connection method are discussed in detail，such as the TIC welding and the laser welding. The advantages and development potential of the technology are introduced in the field of the heterogeneous sheet connection，in combination with the industry development and the use demand，the development of the heterogeneous sheet connection technology is expected，to provide the technical support for the research and development of new heterogeneous sheet connection technology.

1998 energy balance sheet of France

International Nuclear Information System (INIS)

Anon.

1999-01-01

This paper summarizes the results of the energy balance sheet of France for the year 1998 according to the data published by the energy observatory from the general direction of energy and raw materials (DGEMP) and according to the press communication given by C. Pierret, French state secretary of the industry. The following points are commented: the energy balance sheet (national production and energy independence, the energy shares in the consumption), the decay of the energy bill, and the details of the bill by energy type. (J.S.)

Physics of the magnetotail current sheet

International Nuclear Information System (INIS)

Chen, J.

1993-01-01

The Earth's magnetotail plays an important role in the solar-wind--magnetosphere coupling. At the midplane of the magnetotail is a current sheet where the dominant magnetic field component reverses sign. The charged particle motion in and near the current sheet is collisionless and nonintegrable, exhibiting chaotic scattering. The current understanding of the dynamical properties of the charged particle motion is discussed. In particular, the relationships between particle dynamics and global attributes of the system are elucidated. Geometrical properties of the phase space determine important physical observables on both micro- and macroscales

Periodic folding of viscous sheets

Science.gov (United States)

Ribe, Neil M.

2003-09-01

The periodic folding of a sheet of viscous fluid falling upon a rigid surface is a common fluid mechanical instability that occurs in contexts ranging from food processing to geophysics. Asymptotic thin-layer equations for the combined stretching-bending deformation of a two-dimensional sheet are solved numerically to determine the folding frequency as a function of the sheet’s initial thickness, the pouring speed, the height of fall, and the fluid properties. As the buoyancy increases, the system bifurcates from “forced” folding driven kinematically by fluid extrusion to “free” folding in which viscous resistance to bending is balanced by buoyancy. The systematics of the numerically predicted folding frequency are in good agreement with laboratory experiments.

Field evaluation of ZeroFly--an insecticide incorporated plastic sheeting against malaria vectors & its impact on malaria transmission in tribal area of northern Orissa.

Science.gov (United States)

Sharma, S K; Upadhyay, A K; Haque, M A; Tyagi, P K; Mohanty, S S; Mittal, P K; Dash, A P

2009-10-01

Insecticide incorporated plastic sheeting is a new technology to control mosquitoes in emergency shelter places and also temporary habitations in different locations. Therefore, field studies were conducted to assess the efficacy of ZeroFly plastic sheeting treated with deltamethrin on prevailing disease vectors Anopheles culicifacies and An. fluviatilis and its impact on malaria transmission in one of the highly endemic areas of Orissa. The study was conducted in Birkera block of Sundargarh district, Orissa state. The study area comprised 3 villages, which were randomized as ZeroFly plastic sheet, untreated plastic sheet and no sheet area. ZeroFly plastic sheets and untreated plastic sheets were fixed in study and control villages respectively covering all the rooms in each household. Longitudinal studies were conducted on the bioefficacy with the help of cone bioassays, monitoring of the mosquito density through hand catch, floor sheet and exit trap collections and fortnightly domiciliary active surveillance in all the study villages. In ZeroFly plastic sheeting area, there was a significant reduction of 84.7 per cent in the entry rate of total mosquitoes in comparison to pre-intervention phase. There was 56.2 per cent immediate mortality in total mosquitoes in houses with ZeroFly sheeting. The overall feeding success rate of mosquitoes in the trial village was only 12.5 per cent in comparison to 49.7 and 51.1 per cent in villages with untreated plastic sheet and no sheet respectively. There was a significant reduction of 65.0 and 70.5 per cent in malaria incidence in ZeroFly plastic sheeting area as compared to untreated plastic sheet and no sheet area respectively. Our study showed that introduction of ZeroFly plastic sheets in a community-based intervention programme is operationally feasible to contain malaria especially in the high transmission difficult areas.