Determining a strategy for efficiently managing sign retroreflectivity in New Hampshire.

Science.gov (United States)

2012-05-01

The Manual on Uniform Traffic Control Devices (MUTCD) has developed minimum retroreflectivity requirements for sign sheeting that will : become a federal mandate for roadside signs in 2015 and for overhead signs in 2018. In 2012, the New Hampshire De...

An advanced material model for aluminum sheet forming at elevated temperatures

NARCIS (Netherlands)

Kurukuri, S.; Miroux, Alexis; Ghosh, Manojit; van den Boogaard, Antonius H.; Oñate, E.; Owen, D.R.J; Suárez, B.

2009-01-01

A physically-based material model according to Nes is used to simulate the warm forming of Al-Mg-Si sheet. This model incorporates the influence of the temperature and strain rate on the flow stress and on the hardening rate based on storage and dynamic recovery of dislocations. The effect of size

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.

A new tensile impact test for the toughness characterization of sheet material

Science.gov (United States)

Könemann, Markus; Lenz, David; Brinnel, Victoria; Münstermann, Sebastian

2018-05-01

In the past, the selection of suitable steels has been carried out primarily based on the mechanical properties of different steels. One of these properties is the resistance against crack propagation. For many constructions, this value plays an important role, because it can compare the impact toughness of different steel grades easily and gives information about the loading capacity of the specific materials. For thin sheets, impact toughness properties were usually not considered. One of the reasons for this is that the Charpy-impact test is not applicable for sheets with thicknesses below 2 mm. For a long time, this was not relevant because conventional steels had a sufficient impact toughness in a wide temperature range. However, since new multiphase steel grades with improved mechanical property exploitations are available, it turned out that impact toughness properties need to be considered during the component design phase, as the activation of the cleavage fracture mechanism is observed under challenging loading conditions. Therefore, this work aims to provide a new and practical testing procedure for sheet material or thin walled structures. The new testing procedure is based on tensile tests conducted in an impact pendulum similar to the Charpy impact hammer. A new standard geometry is provided, which enables a comparison between different steels or steel grades. A connection to the conventional Charpy test is presented using a damage mechanics model, which predicts material failure with consideration of to the stress state at various temperatures. Different specimen geometries are analysed to cover manifold stress states. A special advantage of the damage mechanics model is also the possibility to predict the materials behaviour in the transition area. To verify the method a conventional steel was tested in Charpy tests as well as in the new tensile impact test.

The Effects of Plastic Anisotropy in Warm and Hot Forming of Magnesium Sheet Materials

Science.gov (United States)

Taleff, Eric M.; Antoniswamy, Aravindha R.; Carpenter, Alexander J.; Yavuz, Emre

Mg alloy sheet materials often exhibit plastic anisotropy at room temperature as a result of the limited slip systems available in the HCP lattice combined with a commonly strong basal texture. Less well studied is plastic anisotropy developed at the elevated temperatures associated with warm and hot forming. At these elevated temperatures, particularly above 200°C, the activation of additional slip systems significantly increases ductility. However, plastic anisotropy is also induced at elevated temperatures by a strong crystallographic texture, and it can require an accounting in material constitutive models to achieve accurate forming simulations. The type and degree of anisotropy under these conditions depend on both texture and deformation mechanism. The current understanding of plastic anisotropy in Mg AZ31B and ZEK100 sheet materials at elevated temperatures is reviewed in this article. The recent construction of material forming cases is also reviewed with strategies to account for plastic anisotropy in forming simulations.

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.

Difficulties in using Material Safety Data Sheets to analyse occupational exposures to contact allergens

DEFF Research Database (Denmark)

Friis, Ulrik F; Menné, Torkil; Flyvholm, Mari-Ann

2015-01-01

BACKGROUND: Information on the occurrence of contact allergens and irritants is crucial for the diagnosis of occupational contact dermatitis. Material Safety Data Sheets (MSDS) are important sources of information concerning exposures in the workplace. OBJECTIVE: From a medical viewpoint...

Preparation of Ni(OH)2-graphene sheet-carbon nanotube composite as electrode material for supercapacitors

International Nuclear Information System (INIS)

Liu, Y.F.; Yuan, G.H.; Jiang, Z.H.; Yao, Z.P.; Yue, M.

2015-01-01

Highlights: • CNT is introduced into graphene to prevent restacking by solvothermal reaction. • Ethanol as a low cost and green solvent is used in solvothermal reaction. • Ni(OH) 2 nanosheets were chemically precipitated into GS-CNT to increase the capacitance. - Abstract: Ni(OH) 2 -graphene sheet-carbon nanotube composite was prepared for supercapacitance materials through a simple two-step process involving solvothermal synthesis of graphene sheet-carbon nanotube composite in ethanol and chemical precipitation of Ni(OH) 2 . According to N 2 adsorption/desorption analysis, the Brunauer–Emmett–Teller surface area of graphene sheet-carbon nanotube composite (109.07 m 2 g −1 ) was larger than that of pure graphene sheets (32.06 m 2 g −1 ), indicating that the added carbon nanotubes (15 wt.%) could prevent graphene sheets from restacking in the solvothermal reaction. The results of field emission scanning electron microscopy and transmission electron microscopy showed that Ni(OH) 2 nanosheets were uniformly loaded into the three-dimensional interconnected network of graphene sheet-carbon nanotube composite. The microstructure enhanced the rate capability and utilization of Ni(OH) 2 . The specific capacitance of Ni(OH) 2 -graphene sheet-carbon nanotube composite was 1170.38 F g −1 at a current density of 0.2 A g −1 in the 6 mol L −1 KOH solution, higher than those provided by pure Ni(OH) 2 (953.67 Fg −1 ) and graphene sheets (178.25 F g −1 ). After 20 cycles at each current density (0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 A g −1 ), the capacitance of Ni(OH) 2 -graphene sheet-carbon nanotube composite decreased 26.96% of initial capacitance compared to 74.52% for pure Ni(OH) 2

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

Application Of A New Semi-Empirical Model For Forming Limit Prediction Of Sheet Material Including Superposed Loads Of Bending And Shearing

Science.gov (United States)

Held, Christian; Liewald, Mathias; Schleich, Ralf; Sindel, Manfred

2010-06-01

The use of lightweight materials offers substantial strength and weight advantages in car body design. Unfortunately such kinds of sheet material are more susceptible to wrinkling, spring back and fracture during press shop operations. For characterization of capability of sheet material dedicated to deep drawing processes in the automotive industry, mainly Forming Limit Diagrams (FLD) are used. However, new investigations at the Institute for Metal Forming Technology have shown that High Strength Steel Sheet Material and Aluminum Alloys show increased formability in case of bending loads are superposed to stretching loads. Likewise, by superposing shearing on in plane uniaxial or biaxial tension formability changes because of materials crystallographic texture. Such mixed stress and strain conditions including bending and shearing effects can occur in deep-drawing processes of complex car body parts as well as subsequent forming operations like flanging. But changes in formability cannot be described by using the conventional FLC. Hence, for purpose of improvement of failure prediction in numerical simulation codes significant failure criteria for these strain conditions are missing. Considering such aspects in defining suitable failure criteria which is easy to implement into FEA a new semi-empirical model has been developed considering the effect of bending and shearing in sheet metals formability. This failure criterion consists of the combination of the so called cFLC (combined Forming Limit Curve), which considers superposed bending load conditions and the SFLC (Shear Forming Limit Curve), which again includes the effect of shearing on sheet metal's formability.

Application Of A New Semi-Empirical Model For Forming Limit Prediction Of Sheet Material Including Superposed Loads Of Bending And Shearing

International Nuclear Information System (INIS)

Held, Christian; Liewald, Mathias; Schleich, Ralf; Sindel, Manfred

2010-01-01

The use of lightweight materials offers substantial strength and weight advantages in car body design. Unfortunately such kinds of sheet material are more susceptible to wrinkling, spring back and fracture during press shop operations. For characterization of capability of sheet material dedicated to deep drawing processes in the automotive industry, mainly Forming Limit Diagrams (FLD) are used. However, new investigations at the Institute for Metal Forming Technology have shown that High Strength Steel Sheet Material and Aluminum Alloys show increased formability in case of bending loads are superposed to stretching loads. Likewise, by superposing shearing on in plane uniaxial or biaxial tension formability changes because of materials crystallographic texture. Such mixed stress and strain conditions including bending and shearing effects can occur in deep-drawing processes of complex car body parts as well as subsequent forming operations like flanging. But changes in formability cannot be described by using the conventional FLC. Hence, for purpose of improvement of failure prediction in numerical simulation codes significant failure criteria for these strain conditions are missing. Considering such aspects in defining suitable failure criteria which is easy to implement into FEA a new semi-empirical model has been developed considering the effect of bending and shearing in sheet metals formability. This failure criterion consists of the combination of the so called cFLC (combined Forming Limit Curve), which considers superposed bending load conditions and the SFLC (Shear Forming Limit Curve), which again includes the effect of shearing on sheet metal's formability.

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.

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

Toxic substances registry system: Index of material safety data sheets

Science.gov (United States)

1993-01-01

The Material Safety Data Sheets (MSDS's) listed in this index reflect product inventories and associated MSDS's which were submitted to the Toxic Substances Registry database maintained by the Base Operations Contractor at the Kennedy Space Center. The purpose of this index is to provide KSC government, contractor, and tenant organizations a means to access information on the hazards associated with these chemicals. The Toxic Substance Registry Service (TSRS) was established to manage information dealing with the storage and use of toxic and otherwise hazardous materials at KSC. As a part of this service, the BOC Environmental Health Services maintains a central repository of MSDS's which were provided to TSRS. The data on the TSRS are obtained from NASA, contractor, and tenant organizations who use or store hazardous materials at KSC. It is the responsibility of these organizations to conduct inventories, obtain MSDS's, distribute Hazard Communication information to their employees, and otherwise implement compliance with appropriate Federal, State, and NASA Hazard Communication and Worker Right-to-Know regulations and policies.

IMPROVED AGING PERFORMANCE OF VIRGIN EPDM ROOF-SHEETING COMPOUNDS WITH AMINE-DEVULCANIZED EPDM WEATHERSTRIP MATERIAL

NARCIS (Netherlands)

Dijkhuis, K. A. J.; Dierkes, W. K.; Noordermeer, J. W. M.; Sutanto, P.

2008-01-01

Sulfur-cured EPDM building-profile material was reclaimed in a co-rotating twin-screw extruder using hexadecylamine as reclaiming aid. This reclaim was blended with increasing amounts of a virgin EPDM roof-sheeting masterbatch and cured at temperatures allowing for a reversion-free vulcanization.

Impulse Hydroforming Method for Very Thin Sheets from Metallic or Hybrid Materials

OpenAIRE

Beerwald, C.; Beerwald, M.; Dirksen, U.; Henselek, A.

2010-01-01

Forming of very thin metallic and hybrid material foils is a demanding task in several application areas as for example in food or pharmaceutical packaging industries. Narrow forming limits of very thin sheet metals as well as minor process reliability due to necessary exact tool manufacturing (small punch-die clearance), both, causes abiding interest in new and innovative forming processes. In this contribution a new method using high pressure pulses will be introduced to form small geometry...

Bi2S3microspheres grown on graphene sheets as low-cost counter-electrode materials for dye-sensitized solar cells

Science.gov (United States)

Li, Guang; Chen, Xiaoshuang; Gao, Guandao

2014-02-01

In this work, we synthesized 3D Bi2S3 microspheres comprised of nanorods grown along the (211) facet on graphene sheets by a solvothermal route, and investigated its catalytic activities through I-V curves and conversion efficiency tests as the CE in DSSCs. Although the (211) facet has a large band gap for a Bi2S3 semiconductor, owing to the introduction of graphene into the system, its short-circuit current density, open-circuit voltage, fill factor, and efficiency were Jsc = 12.2 mA cm-2, Voc = 0.75 V, FF = 0.60, and η = 5.5%, respectively. By integrating it with graphene sheets, our material achieved the conversion efficiency of 5.5%, which is almost triple the best conversion efficiency value of the DSSCs with (211)-faceted 3D Bi2S3 without graphene (1.9%) reported in the latest literature. Since this conversion-efficient 3D material grown on the graphene sheets significantly improves its catalytic properties, it paves the way for designing and applying low-cost Pt-free CE materials in DSSC from inorganic nanostructures.In this work, we synthesized 3D Bi2S3 microspheres comprised of nanorods grown along the (211) facet on graphene sheets by a solvothermal route, and investigated its catalytic activities through I-V curves and conversion efficiency tests as the CE in DSSCs. Although the (211) facet has a large band gap for a Bi2S3 semiconductor, owing to the introduction of graphene into the system, its short-circuit current density, open-circuit voltage, fill factor, and efficiency were Jsc = 12.2 mA cm-2, Voc = 0.75 V, FF = 0.60, and η = 5.5%, respectively. By integrating it with graphene sheets, our material achieved the conversion efficiency of 5.5%, which is almost triple the best conversion efficiency value of the DSSCs with (211)-faceted 3D Bi2S3 without graphene (1.9%) reported in the latest literature. Since this conversion-efficient 3D material grown on the graphene sheets significantly improves its catalytic properties, it paves the way for

Preparation of Ni(OH){sub 2}-graphene sheet-carbon nanotube composite as electrode material for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Liu, Y.F. [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Environmental and Chemical Engineering, Heilongjiang University of Science and Technology, Harbin 150022 (China); Yuan, G.H., E-mail: ygh@hit.edu.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Jiang, Z.H., E-mail: jiangzhaohua@hit.edu.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Yao, Z.P. [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Yue, M. [Shenzhen BTR New Energy Materials INC., Shenzhen 528206 (China)

2015-01-05

Highlights: • CNT is introduced into graphene to prevent restacking by solvothermal reaction. • Ethanol as a low cost and green solvent is used in solvothermal reaction. • Ni(OH){sub 2} nanosheets were chemically precipitated into GS-CNT to increase the capacitance. - Abstract: Ni(OH){sub 2}-graphene sheet-carbon nanotube composite was prepared for supercapacitance materials through a simple two-step process involving solvothermal synthesis of graphene sheet-carbon nanotube composite in ethanol and chemical precipitation of Ni(OH){sub 2}. According to N{sub 2} adsorption/desorption analysis, the Brunauer–Emmett–Teller surface area of graphene sheet-carbon nanotube composite (109.07 m{sup 2} g{sup −1}) was larger than that of pure graphene sheets (32.06 m{sup 2} g{sup −1}), indicating that the added carbon nanotubes (15 wt.%) could prevent graphene sheets from restacking in the solvothermal reaction. The results of field emission scanning electron microscopy and transmission electron microscopy showed that Ni(OH){sub 2} nanosheets were uniformly loaded into the three-dimensional interconnected network of graphene sheet-carbon nanotube composite. The microstructure enhanced the rate capability and utilization of Ni(OH){sub 2}. The specific capacitance of Ni(OH){sub 2}-graphene sheet-carbon nanotube composite was 1170.38 F g{sup −1} at a current density of 0.2 A g{sup −1} in the 6 mol L{sup −1} KOH solution, higher than those provided by pure Ni(OH){sub 2} (953.67 Fg{sup −1}) and graphene sheets (178.25 F g{sup −1}). After 20 cycles at each current density (0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 A g{sup −1}), the capacitance of Ni(OH){sub 2}-graphene sheet-carbon nanotube composite decreased 26.96% of initial capacitance compared to 74.52% for pure Ni(OH){sub 2}.

Experimental Characterization and Material Modelling of an AZ31 Magnesium Sheet Alloy at Elevated Temperatures under Consideration of the Tension-Compression Asymmetry

Science.gov (United States)

Behrens, B.-A.; Bouguecha, A.; Bonk, C.; Dykiert, M.

2017-09-01

Magnesium sheet alloys have a great potential as a construction material in the aerospace and automotive industry. However, the current state of research regarding temperature dependent material parameters for the description of the plastic behaviour of magnesium sheet alloys is scarce in literature and accurate statements concerning yield criteria and appropriate characterization tests to describe the plastic behaviour of a magnesium sheet alloy at elevated temperatures in deep drawing processes are to define. Hence, in this paper the plastic behaviour of the well-established magnesium sheet alloy AZ31 has been characterized by means of convenient mechanical tests (e. g. tension, compression and biaxial tests) at temperatures between 180 and 230 °C. In this manner, anisotropic and hardening behaviour as well as differences between the tension-compression asymmetry of the yield locus have been estimated. Furthermore, using the evaluated data from the above mentioned tests, two different yield criteria have been parametrized; the commonly used Hill’48 and an orthotropic yield criterion, CPB2006, which was developed especially for materials with hexagonal close packed lattice structure and is able to describe an asymmetrical yielding behaviour regarding tensile and compressive stress states. Numerical simulations have been finally carried out with both yield functions in order to assess the accuracy of the material models.

Compensation of the Persistent Current Multipoles in the LHC Dipoles by making the Coil Protection Sheet from Soft Magnetic Material

CERN Document Server

Völlinger, C

2000-01-01

This note presents a scheme for compensating the persistent current multipole errors of the LHC dipoles by making the coil protection sheets from soft magnetic material of 0.5 mm thickness. The material properties assumed in this study are those of iron sheets with a very low content of impurities (99.99% pure Fe). The non-linearities in the upramp cycle on the b3 multipole component can be reduced by the factor of four (while decreasing the b5 variation by the factor of two. Using sheets of slightly different thicknesses offers a tuning possibility for the series magnet coils and can compensate deviations arising from cables of different suppliers. The calculation method is based on a semi-analytical hysteresis model for hard superconductors and an M(B) - iteration using the method of coupled boundary elements - finite elements (BEM - FEM). It is now possible to compute persistent current multipole errors of geometries with arbitrarily shaped iron yokes and thin layers of soft magnetic material such as tunin...

Direct Laser Writing of Single-Material Sheets with Programmable Self-Rolling Capability

Science.gov (United States)

Bauhofer, Anton; KröDel, Sebastian; Bilal, Osama; Daraio, Chiara; Constantinescu, Andrei

Direct laser writing, a sub-class of two-photon polymerization, facilitates 3D-printing of single-material microstructures with inherent residual stresses. Here we show that controlled distribution of these stresses allows for fast and cost-effective fabrication of structures with programmable self-rolling capability. We investigate 2D sheets that evolve into versatile 3D structures. Precise control over the shape morphing potential is acquired through variations in geometry and writing parameters. Effects of capillary action and gravity were shown to be relevant for very thin sheets (thickness 1.5um) are dominated by residual stresses and adhesion forces. The presented structures create local tensions up to 180MPa, causing rolling curvatures of 25E3m-1. A comprehensive analytical model that captures the relevant influence factors was developed based on laminate plate theory. The predicted curvature and directionality correspond well with the experimentally obtained data. Potential applications are found in drug encapsulation and particle traps for emulsions with differing surface energies. This work was supported by the Swiss National Science Foundation.

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...

Tungsten oxide nanowires grown on graphene oxide sheets as high-performance electrochromic material

International Nuclear Information System (INIS)

Chang, Xueting; Sun, Shibin; Dong, Lihua; Hu, Xiong; Yin, Yansheng

2014-01-01

Graphical abstract: Electrochromic mechanism of tungsten oxide nanowires-reduced graphene oxide composite. - Highlights: • A novel inorganic-nano-carbon hybrid composite was prepared. • The hybrid composite has sandwich-like structure. • The hybrid composite exhibited high-quality electrohcromic performance. - Abstract: In this work, we report the synthesis of a novel hybrid electrochromic composite through nucleation and growth of ultrathin tungsten oxide nanowires on graphene oxide sheets using a facile solvothermal route. The competition between the growth of tungsten oxide nanowires and the reduction of graphene oxide sheets leads to the formation of sandwich-structured tungsten oxide-reduced graphene oxide composite. Due to the strongly coupled effect between the ultrathin tungsten oxide nanowires and the reduced graphene oxide nanosheets, the novel electrochromic composite exhibited high-quality electrochromic performance with fast color-switching speed, good cyclic stability, and high coloration efficiency. The present tungsten oxide-reduced graphene oxide composite represents a new approach to prepare other inorganic-reduced graphene oxide hybrid materials for electrochemical applications

Rapidly cast crystalline thin sheet materials

International Nuclear Information System (INIS)

Warlimont, H.; Emmerich, K.

1986-01-01

The current state and progress of casting thin sheet and ribbons directly from the melt are reviewed. First, the solidification phenomena pertinent to the process are outlined. Subsequently, Fe-Si,l Fe-Si-Al, Fe-Nd-B, Ag-Cu-Ti, alloy steels, Ni superalloys and Si are treated as examples. Finally, the information available on process development is critically assessed

LSE-Sign: A lexical database for Spanish Sign Language.

Science.gov (United States)

Gutierrez-Sigut, Eva; Costello, Brendan; Baus, Cristina; Carreiras, Manuel

2016-03-01

The LSE-Sign database is a free online tool for selecting Spanish Sign Language stimulus materials to be used in experiments. It contains 2,400 individual signs taken from a recent standardized LSE dictionary, and a further 2,700 related nonsigns. Each entry is coded for a wide range of grammatical, phonological, and articulatory information, including handshape, location, movement, and non-manual elements. The database is accessible via a graphically based search facility which is highly flexible both in terms of the search options available and the way the results are displayed. LSE-Sign is available at the following website: http://www.bcbl.eu/databases/lse/.

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

Metacarpal sign

Directory of Open Access Journals (Sweden)

Barbara Nieradko-Iwanicka

2018-02-01

Full Text Available Background Archibald's sign, or metacarpal sign is defined as shortening of the IV and V metacarpal bones, is a rare phenomenon found in the Turner syndrome, homocystinuria and in Albright's osteodystrophy. Objectives The aim of the article was to show a rare case of metacarpal sign with atypical shortening of the III and IV metacarpal bones not connected with gonadal dysgenesia, genetic disorders nor osteodystrophy. Material and methods Case report of a 60-year-old female patient. Results Artchibald's metacarpal sign in the described case was accompanied by erosive arthritis in the left lower extremity. No features of genetic disorders nor gonadal disgenesia were found in the patient. Undifferentiated seronegative asymmetric erosive arthritis developed in the patient. The level of parathormon was within the normal range. No signs of tumor were seen in bone scintigraphy. Conclusions Archibald's metacarpal sign may be present in patients without genetic disorders.

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...

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)

Synthesis and Characterization of Silicon Nanoparticles Inserted into Graphene Sheets as High Performance Anode Material for Lithium Ion Batteries

Directory of Open Access Journals (Sweden)

Yong Chen

2014-01-01

Full Text Available Silicon nanoparticles have been successfully inserted into graphene sheets via a novel method combining freeze-drying and thermal reduction. The structure, electrochemical performance, and cycling stability of this anode material were characterized by SEM, X-ray diffraction (XRD, charge/discharge cycling, and cyclic voltammetry (CV. CV showed that the Si/graphene nanocomposite exhibits remarkably enhanced cycling performance and rate performance compared with bare Si nanoparticles for lithium ion batteries. XRD and SEM showed that silicon nanoparticles inserted into graphene sheets were homogeneous and had better layered structure than the bare silicon nanoparticles. Graphene sheets improved high rate discharge capacity and long cycle-life performance. The initial capacity of the Si nanoparticles/graphene keeps above 850 mAhg−1 after 100 cycles at a rate of 100 mAg−1. The excellent cycle performances are caused by the good structure of the composites, which ensured uniform electronic conducting sheet and intensified the cohesion force of binder and collector, respectively.

A Novel CAE Method for Compression Molding Simulation of Carbon Fiber-Reinforced Thermoplastic Composite Sheet Materials

Directory of Open Access Journals (Sweden)

Yuyang Song

2018-06-01

Full Text Available Its high-specific strength and stiffness with lower cost make discontinuous fiber-reinforced thermoplastic (FRT materials an ideal choice for lightweight applications in the automotive industry. Compression molding is one of the preferred manufacturing processes for such materials as it offers the opportunity to maintain a longer fiber length and higher volume production. In the past, we have demonstrated that compression molding of FRT in bulk form can be simulated by treating melt flow as a continuum using the conservation of mass and momentum equations. However, the compression molding of such materials in sheet form using a similar approach does not work well. The assumption of melt flow as a continuum does not hold for such deformation processes. To address this challenge, we have developed a novel simulation approach. First, the draping of the sheet was simulated as a structural deformation using the explicit finite element approach. Next, the draped shape was compressed using fluid mechanics equations. The proposed method was verified by building a physical part and comparing the predicted fiber orientation and warpage measurements performed on the physical parts. The developed method and tools are expected to help in expediting the development of FRT parts, which will help achieve lightweight targets in the automotive industry.

Material characterization and finite element simulations of aluminum alloy sheets during non-isothermal forming process

Science.gov (United States)

Zhang, Nan

The utilization of more non-ferrous materials is one of the key factors to succeed out of the constantly increasing demand for lightweight vehicles in automotive sector. Aluminum-magnesium alloys have been identified as the most promising substitutions to the conventional steel without significant compromise in structural stiffness and strength. However, the conventional forming methods to deform the aluminum alloy sheets are either costly or insufficient in formability which limit the wide applications of aluminum alloy sheets. A recently proposed non-isothermal hot stamping approach, which is also referred as Hot Blank - Cold Die (HB-CD) stamping, aims at fitting the commercial grade aluminum alloy sheets, such as AA5XXX and AA7XXX, into high-volume and cost-effective production for automotive sector. In essence, HB-CD is a mutation of the conventional hot stamping approach for boron steel (22MnB5) which deforms the hot blank within the cold tool set. By elevating the operation temperature, the formability of aluminum alloy sheets can be significantly improved. Meanwhile, heating the blank only and deforming within the cold tool sets allow to reduce the energy and time consumed. This research work aims at conducting a comprehensive investigation of HB-CD with particular focuses on material characterization, constitutive modeling and coupled thermo-mechanical finite element simulations with validation. The material properties of AA5182-O, a popular commercial grade of aluminum alloy sheet in automotive sector, are obtained through isothermal tensile testing at temperatures from 25° to 300°, covering a quasi-static strain-rate range (0.001--0.1s-1). As the state-of-the-art non-contact strain measurement technique, digital image correlation (DIC) system is utilized to evaluate the stress-strain curves as well as to reveal the details of material deformation with full-field and multi-axis strain measurement. Material anisotropy is characterized by extracting the

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

Making an Inexpensive Electromagnetic Wiggler Using Sheet Materials for the Coils

CERN Document Server

Herman-Biallas, George; Hiatt, Thomas; Neil, George; Snyder, Michael

2004-01-01

An inexpensive electromagnetic wiggler, made with twenty-eight, 4 cm periods with a K of 1 and gap of 2.6 cm was made within 10 weeks after receipt of order by an industrial machine shop. The coil design used sheet and plate materials cut to shapes using water jet cutting and was assembled in a simple stack design. The coil design extends the serpentine conductor design of the Duke OK4 to more and smaller conductors. The coils are conduction cooled to imbedded cooling plates. The wiggler features graded end pole fields, trim coil compensation for end field errors and mirror plates on the ends to avoid three dimensional end field effects. Details of the methods used in construction and the wiggler performance are presented.

Training Sessions and Materials Present Ways to Improve System Efficiency: OIT Technical Assistance Fact Sheet: Training

International Nuclear Information System (INIS)

Ericksen, E.

1999-01-01

Interested in learning about innovative ways to improve the efficiency of your plant's steam, electric motor, and compressed air systems? This US Department of Energy Office of Industrial Technologies fact sheet offers information regarding training sessions, teleconferences, and various training materials to teach you and your company ways to reduce energy use, save money, and reduce waste and pollution through system optimization

Binding SnO2 nanocrystals in nitrogen-doped graphene sheets as anode materials for lithium-ion batteries.

Science.gov (United States)

Zhou, Xiaosi; Wan, Li-Jun; Guo, Yu-Guo

2013-04-18

Hybrid anode materials for Li-ion batteries are fabricated by binding SnO2 nanocrystals (NCs) in nitrogen-doped reduced graphene oxide (N-RGO) sheets by means of an in situ hydrazine monohydrate vapor reduction method. The SnO2NCs in the obtained SnO2NC@N-RGO hybrid material exhibit exceptionally high specific capacity and high rate capability. Bonds formed between graphene and SnO2 nanocrystals limit the aggregation of in situ formed Sn nanoparticles, leading to a stable hybrid anode material with long cycle life. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

23 CFR Appendix to Subpart F of... - Alternate Method of Determining the Color of Retroreflective Sign Materials and Pavement Marking...

Science.gov (United States)

2010-04-01

... Retroreflective Sign Materials and Pavement Marking Materials Appendix to Subpart F of Part 655 Highways FEDERAL... Pavement Marking Materials 1. Although the FHWA Color Tolerance Charts depreciate the use of... for Retroreflective Pavement Marking Material With CIE 2° Standard Observer and 45/0 (0/45) Geometry...

Comparative properties of ceramic-based roofing sheets from local ...

African Journals Online (AJOL)

Ceramic roofing sheets were fabricated in the laboratory by using ideal raw materials. The fabricating materials are coiled coconut fibre, palm fruit fibre, fresh water, river sand, polymeric dust, saw dust and cement. The resulting product was compared with factory -produced ceramic-based roofing sheets that are easily ...

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.

X-ray screening materials

International Nuclear Information System (INIS)

Wardley, R.B.

1981-01-01

This invention relates to x-ray screening materials and especially to materials in sheet form for use in the production of, for example, protective clothing such as aprons and lower back shields, curtains, mobile screens and suspended shields. The invention is based on the observation that x-ray screening materials in sheet form having greater flexiblity than the hitherto known x-ray screening materials of the same x-ray absorber content can be produced if, instead of using a single sheet of filled sheet material of increased thickness, one uses a plurality of sheets of lesser thickness together forming a laminar material of the desired thickness and one bonds the individual sheets together at their edges and, optionally, at other spaced apart points away from the edges thereby allowing one sheet to move relative to another. (U.K.)

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.

Development of powder metallurgy 2XXX series Al alloy plate and sheet materials for high temperature aircraft structural applications, FY 1983/1984

Science.gov (United States)

Chellman, D. J.

1985-01-01

The objective of this investigation is to fabricate and evaluate PM 2124 Al alloy plate and sheet materials according to NASA program goals for damage tolerance and fatigue resistance. Previous research has indicated the outstanding strength-toughness relationship available with PM 2124 Al-Zr modified alloy compositions in extruded product forms. The range of processing conditions was explored in the fabrication of plate and sheet gage materials, as well as the resultant mechanical and metallurgical properties. The PM composition based on Al-3.70 Cu-1.85 Mg-0.20 Mn with 0.60 wt. pct. Zr was selected. Flat rolled material consisting of 0.250 in. thick plate was fabricated using selected thermal mechanical treatments (TMT). The schedule of TMT operations was designed to yield the extreme conditions of grain structure normally encountered in the fabrication of flat rolled products, specifically recrystallized and unrecrystallized. The PM Al alloy plate and sheet materials exhibited improved strength properties at thin gages compared to IM Al alloys, as a consequence of their enhanced ability to inhibit recrystallization and grain growth. In addition, the PM 2124 Al alloys offer much better combinations of strength and toughnessover equivalent IM Al. The alloy microstructures were examined by optical metallographic texture techniques in order to establish the metallurgical basis for these significant property improvements.

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

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...

Abdominal X-ray signs of intra-intestinal drug smuggling.

Science.gov (United States)

Niewiarowski, Sylwia; Gogbashian, Andrew; Afaq, Asim; Kantor, Robin; Win, Zarni

2010-05-01

"Body packers" either swallow or insert drug filled packets rectally or vaginally in order to smuggle illicit drugs. AXR is used routinely to screen suspects for the presence of intra-intestinal drug packages. AXR diagnosis can be difficult as stool or gas within the intestine may resemble ingested foreign bodies. We identify the frequency and co-existence of several signs; tic-tac sign, rosette sign, double condom sign, dense surrounding material, density and discover a new sign; parallelism, which will aid in increasing the radiological accuracy. We retrospectively reviewed 285 AXRs performed for suspicion of drug smuggling during the period of March 2006-March 2009 to identify the frequency of these signs. Of the 285 AXRs performed 59 were positive, 221 negative and five were indeterminate. The tic-tac sign was present in 93%, double condom sign in 73%, dense surrounding wrapping material in 36% and parallelism in 27%. Sixty one percentage of drug packages were iso-dense to faeces and 39% hyperdense. Twenty percentage of the positive abdominal radiographs demonstrated one of the radiographic signs, 39% demonstrated two signs, 32% demonstrated three and 7% four. The most common radiographic sign combination was the tic-tac sign with either dense surrounding material or double condom sign. The most commonly encountered radiographic sign is the tic-tac sign, followed by the double condom sign and dense surrounding material. We also discover a new sign, "parallelism" which although uncommon is highly specific. Accuracy is further increased by comparing the density of packages to faeces and looking for the co-existence of multiple signs. Copyright (c) 2010 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

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 Bottoming on Material Property during Sheet Forming Process through Finite Element Method

Science.gov (United States)

Akinlabi, Stephen A.; Fatoba, Olawale S.; Mashinini, Peter M.; Akinlabi, Esther T.

2018-03-01

Metal forming is one of the conventional manufacturing processes of immense relevance till date even though modern manufacturing processes have evolved over the years. It is a known fact that material tends to return or spring back to its original form during forming or bending. The phenomena have been well managed through its application in various manufacturing processes by compensating for the spring back through overbending and bottoming. Overbending is bending the material beyond the desired shape to allow the material to spring back to the expected shape. Bottoming, on the other hand, is a process of undergoing plastic deformation at the point of bending. This study reports on the finite element analysis of the effect of bottoming on the material property during the sheet forming process with the aim of optimising the process. The result of the analysis revealed that the generated plastic strains are in the order between 1.750e00-1 at the peak of the bending and 3.604e00-2, which was at the early stage of the bending.

Standard Test Methods for Solar Energy Transmittance and Reflectance (Terrestrial) of Sheet Materials

CERN Document Server

American Society for Testing and Materials. Philadelphia

1971-01-01

1.1 These test methods cover the measurement of solar energy transmittance and reflectance (terrestrial) of materials in sheet form. Method A, using a spectrophotometer, is applicable for both transmittance and reflectance and is the referee method. Method B is applicable only for measurement of transmittance using a pyranometer in an enclosure and the sun as the energy source. Specimens for Method A are limited in size by the geometry of the spectrophotometer while Method B requires a specimen 0.61 m2 (2 ft2). For the materials studied by the drafting task group, both test methods give essentially equivalent results. 1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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.

Extruded expanded polystyrene sheets coated by TiO{sub 2} as new photocatalytic materials for foodstuffs packaging

Energy Technology Data Exchange (ETDEWEB)

Loddo, V.; Marci, G. [Schiavello-Grillone Photocatalysis Group - Dipartimento di Ingegneria Elettrica, Elettronica e delle Telecomunicazioni, di tecnologie Chimiche, Automatica e modelli Matematici - Universita degli Studi di Palermo, Viale delle Scienze (Ed. 6) - 90128 Palermo (Italy); Palmisano, G., E-mail: giovanni_palmisano@yahoo.it [Schiavello-Grillone Photocatalysis Group - Dipartimento di Ingegneria Elettrica, Elettronica e delle Telecomunicazioni, di tecnologie Chimiche, Automatica e modelli Matematici - Universita degli Studi di Palermo, Viale delle Scienze (Ed. 6) - 90128 Palermo (Italy); Yurdakal, S. [Kimya Boeluemue, Fen-Edebiyat Fakueltesi, Afyon Kocatepe Ueniversitesi - Ahmet Necdet Sezer Kampuesue - 03200 Afyon (Turkey); Brazzoli, M.; Garavaglia, L. [Sirap-Gema S.p.A. - Via Industriale, 1/3 - 25028 Verolanuova (Brescia) (Italy); Palmisano, L., E-mail: leonardo.palmisano@unipa.it [Schiavello-Grillone Photocatalysis Group - Dipartimento di Ingegneria Elettrica, Elettronica e delle Telecomunicazioni, di tecnologie Chimiche, Automatica e modelli Matematici - Universita degli Studi di Palermo, Viale delle Scienze (Ed. 6) - 90128 Palermo (Italy)

2012-11-15

Highlights: Black-Right-Pointing-Pointer An extruded polystyrene has been functionalised by TiO{sub 2}. Black-Right-Pointing-Pointer A photocatalytic polymer has been developed via a sol-gel method. Black-Right-Pointing-Pointer Thermoformed packagings for foodstuffs application have been prepared. - Abstract: Nanostructured, photoactive anatase TiO{sub 2} sol prepared under very mild conditions using titanium tetraisopropoxide as the precursor is used to functionalise extruded expanded polystyrene (XPS) sheets by spray-coating resulting in stable and active materials functionalised by TiO{sub 2} nanoparticles. Photocatalytic tests of these sheets performed in a batch reactor in gas-solid system under UV irradiation show their successful activity in degrading probe molecules (2-propanol, trimethylamine and ethene). Raman spectra ensure the deposition of TiO{sub 2} as crystalline anatase phase on the polymer surface. The presence of TiO{sub 2} with respect to polymer surface can be observed in SEM images coupled to EDAX mapping allowing to monitor the surface morphology and the distribution of TiO{sub 2} particles. Finally thermoforming of these sheets in industrial standard equipment leads to useful containers for foodstuffs.

Supporting Documentation for the 2008 Update to the Insulation Fact Sheet

Energy Technology Data Exchange (ETDEWEB)

Stovall, Therese K [ORNL

2008-02-01

The Insulation Fact Sheet provides consumers for general guidance and recommended insulation levels for their home. This fact sheet has been on-line since 1995 and this update addresses new insulation materials, as well as updated costs for energy and materials.

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 Dislocation based Constitutive Model for Warm Forming of Aluminum Sheet

NARCIS (Netherlands)

Kurukuri, S.; Ghosh, M.; van den Boogaard, Antonius H.

2008-01-01

The formability of aluminum sheet can be improved considerably by increasing the temperature. At elevated temperatures, the mechanical response of the material becomes strain rate dependent. To accurately simulate warm forming of aluminum sheet, a material model is required that incorporates the

Unraveling metamaterial properties in zigzag-base folded sheets.

Science.gov (United States)

Eidini, Maryam; Paulino, Glaucio H

2015-09-01

Creating complex spatial objects from a flat sheet of material using origami folding techniques has attracted attention in science and engineering. In the present work, we use the geometric properties of partially folded zigzag strips to better describe the kinematics of known zigzag/herringbone-base folded sheet metamaterials such as Miura-ori. Inspired by the kinematics of a one-degree of freedom zigzag strip, we introduce a class of cellular folded mechanical metamaterials comprising different scales of zigzag strips. This class of patterns combines origami folding techniques with kirigami. Using analytical and numerical models, we study the key mechanical properties of the folded materials. We show that our class of patterns, by expanding on the design space of Miura-ori, is appropriate for a wide range of applications from mechanical metamaterials to deployable structures at small and large scales. We further show that, depending on the geometry, these materials exhibit either negative or positive in-plane Poisson's ratios. By introducing a class of zigzag-base materials in the current study, we unify the concept of in-plane Poisson's ratio for similar materials in the literature and extend it to the class of zigzag-base folded sheet materials.

Decontamination efficiency of a sheet of vinyl wall paper as a surface material in radioisotope laboratory

International Nuclear Information System (INIS)

Furukawa, Kazuhiko; Funadera, Kanako

1989-01-01

It has long been desired to prevent surface materials from cracking in a radioisotope laboratory. We applied a sheet of nonflammable wall paper, vinyl cloth, as a surface material to cover concrete wall. It was sufficiently resistant to the reinforced concrete wall cracking. The efficiency of the decontamination of the vinyl cloth was compared with those of stainless steel, iron and painted plates. The contamination and decontamination indices were determined in these surface materials after contamination with [ 32 P]orthophosphate (pH 3, 7 and 11) for 0 to 48 h. Both of the indices of the vinyl cloth were higher than those of the other materials. Further, it was confirmed that the vinyl cloth was resistant to acid and alkaline conditions and radioisotopes could not be permeable. The wipe off efficiency was also investigated in these materials by use of several decontamination detergents. In any reagents tested, the wipe of efficiency of the vinyl cloth was more than 80%. Thus, the vinyl cloth could be used for the surface material and is one of good surface materials in a radioisotope laboratory. (author)

Research showcase, winter 2014 : reducing traffic noise impacts, university transportation centers, advanced prismatic sheeting.

Science.gov (United States)

2014-01-01

This issue of Research Showcase features articles on two successful research efforts, one on quiet : pavements and the other on the bene ts of prismatic sign sheeting, and an article on university : transportation center participation in Florida.

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)

The effect of heat treatment on recrystallized microstructure, precipitation and ductility of hot-rolled Fe-Cr-Al-REM ferritic stainless steel sheets

Energy Technology Data Exchange (ETDEWEB)

Qu, H.P., E-mail: quhuapeng0926@163.com [Institute for Special Steels (Formerly Institute for Structural Materials), Central Iron and Steel Research Institute (CISRI), 76 HaiDianNan Road, Beijing 100081 (China); Lang, Y.P. [Institute for Special Steels (Formerly Institute for Structural Materials), Central Iron and Steel Research Institute (CISRI), 76 HaiDianNan Road, Beijing 100081 (China); Yao, C.F. [Institute for Special Steels (Formerly Institute for Structural Materials), Central Iron and Steel Research Institute (CISRI), 76 HaiDianNan Road, Beijing 100081 (China); Zhuozhou Works, Central Iron and Steel Research Institute (CISRI), 2 HuoJuNan Road, Zhuozhou 072750, Hebei (China); Chen, H.T.; Yang, C.Q. [Institute for Special Steels (Formerly Institute for Structural Materials), Central Iron and Steel Research Institute (CISRI), 76 HaiDianNan Road, Beijing 100081 (China)

2013-02-01

This study presents research works about the effects of heat treatment on recrystallized equiaxed grain size, precipitation, room temperature (RT) toughness and ductile to brittle transition temperature (DBTT) of Fe-Cr-Al-REM ferritic stainless steel (FSS) hot-rolled sheet. Results showed that the recrystallization of hot-rolled Fe-Cr-Al-REM FSS sheet could be completed after annealing treatment at 750 Degree-Sign C for 15 min with the equiaxed grain diameter of approximately 50 {mu}m. Inappropriate annealing treatment would inevitably leads to the unexpected grain coarsening. On the other hand, a great deal of needle-like or spot-like fine aluminum-lanthanum compound Al{sub 11}La{sub 3} precipitates were observed in the ferrite matrix after 1 h aging treatment at 750 Degree-Sign C. The microstructure observation results associated with the impact test definitely illustrated that the Al{sub 11}La{sub 3} precipitates was the reason for the brittle crack in the as-casted ingot and as-forged slab. The real DBTT of the annealed Fe-Cr-Al-REM FSS sheet with average grain size of about 50 {mu}m was -4 Degree-Sign C. Meanwhile, the DBTT of the hot-rolled Fe-Cr-Al-REM stainless steel sheet was evidently increased as the recrystallized grain size increased.

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…

Material Behavior Based Hybrid Process for Sheet Draw-Forging Thin Walled Magnesium Alloys

International Nuclear Information System (INIS)

Sheng, Z.Q.; Shivpuri, R.

2005-01-01

Magnesium alloys are conventionally formed at the elevated temperatures. The thermally improved formability is sensitive to the temperature and strain rate. Due to limitations in forming speeds, tooling strength and narrow processing windows, complex thin walled parts cannot be made by traditional warm drawing or hot forging processes. A hybrid process, which is based on the deformation mechanism of magnesium alloys at the elevated temperature, is proposed that combines warm drawing and hot forging modes to produce an aggressive geometry at acceptable forming speed. The process parameters, such as temperatures, forming speeds etc. are determined by the FEM modeling and simulation. Sensitivity analysis under the constraint of forming limits of Mg alloy sheet material and strength of tooling material is carried out. The proposed approach is demonstrated on a conical geometry with thin walls and with bottom features. Results show that designed geometry can be formed in about 8 seconds, this cannot be formed by conventional forging while around 1000s is required for warm drawing. This process is being further investigated through controlled experiments

Electrode material comprising graphene-composite materials in a graphite network

Science.gov (United States)

Kung, Harold H.; Lee, Jung K.

2017-08-08

A durable electrode material suitable for use in Li ion batteries is provided. The material is comprised of a continuous network of graphite regions integrated with, and in good electrical contact with a composite comprising graphene sheets and an electrically active material, such as silicon, wherein the electrically active material is dispersed between, and supported by, the graphene sheets.

Start-up First Term Sheet: Stumbling Blocks to Avoid

Directory of Open Access Journals (Sweden)

Amalyan Nataly D.

2018-01-01

Full Text Available Start-up relationships with business angel and/or venture capital are similar to a marriage – but with a divorce in mind. The latter necessitates a proper prenuptial agreement signing at the very beginning of the relations. In case of business angel and/or venture capital we are speaking about Term sheet, determining pricing, powers and duties of the board, as well as information, participation and protective rights for the partners. Standard Term sheet consists of three buckets of provisions, defining: (i terms impacting start-up valuation and economic division of profits and proceeds upon a liquidity event, (ii terms impacting control over decision making and (iii investor protection terms. This article focuses on financial and economic aspects of funding agreement, exposing some tricky parts of the Term sheet, threatening to transform potential win-win deals into rupture of relations, crash of the company or even legal battles. The results of the analysis are used to substantiate growing in popular appeal thesis that raising too much money can be detrimental for a startup.

Investigation of the Formability of TRIP780 Steel Sheets

Science.gov (United States)

Song, Yang

The formability of a metal sheet is dependent on its work hardening behaviour and its forming limits; and both aspects must be carefully determined in order to accurately simulate a particular forming process. This research aims to characterize the formability of a TRIP780 sheet steel using advanced experimental testing and analysis techniques. A series of flat rolling and tensile tests, as well as shear tests were conducted to determine the large deformation work hardening behaviour of this TRIP780 steel. Nakazima tests were carried out up to fracture to determine the forming limits of this sheet material. A highly-automated method for generating a robust FLC for sheet materials from DIC strain measurements was created with the help of finite element simulations, and evaluated against the conventional method. A correction algorithm that aims to compensate for the process dependent effects in the Nakazima test was implemented and tested with some success.

What does determine the sign of core in Magnetic Flux Rope structures of the Earth's magnetotail

Directory of Open Access Journals (Sweden)

D. V. Sarafopoulos

2014-09-01

Full Text Available This paper primarily examines the key factors being involved in precisely determining the sign of the core field in a magnetic flux rope (MFR like structure embedded in the tailward plasma flow associated with the Earth's magnetotail. Magnetic flux ropes are frequently detected by satellites moving smoothly northwards (upwards or southwards (downwards and crossing almost the whole plasma sheet; the sign of the rope's core is associated with the local tail's motion: If the tail is bending to an upward or downward direction, then the sign of the rope's core, being essentially an intense By deviation, will be positive or negative correspondingly. On the basis of this observational finding, a major question concerns the mechanism by which the tail's motion is dictated. The reconnection process acting in the tail will obviously produce symmetric structures of MFRs (with respect to the neutral sheet plane; therefore, the detected organized asymmetry may be an additional indication in the whole magnetotail' s dynamics. Moreover, we discuss the issue of the core's sign in cases without any significant magnetotail's motion. A model interpreting the diagnosed behavior is introduced: Once a tailward ion jet is produced in a thinned plasma sheet, it might form clockwise or counterclockwise ion vortices (i.e., loop-like ion currents providing the "magnetic core" with the appropriate sign. The crucial role of the interplanetary By deviation of the magnetic field (IMF is scrutinized and taken into account. The whole model is tested under the condition of long-lasting extraordinary events characterized by a persistent-intense By deviation with a duration up to 34 min. This work, based on Geotail single-satellite measurements, is not a statistical one; it is a first approach allowing the reconstruction of measurements in the whole range of the magnetotail's deflections, from negligible up to stronger significant magnetotail movements, and should be therefore

Development of Rolling Schedules for AZ31 Magnesium Alloy Sheets

Science.gov (United States)

2015-06-01

Materials 2 2.2 Hot Rolling 3 2.2 Sample Characterization: Microstructure and Tensile Properties 3 3. Rolling Experiments 5 3.1 High-Temperature...material systems for protective and structural applications, especially in ground vehicles. Magnesium (Mg), due to its low density (~25% that of steel ...applications, wrought Mg is difficult to produce in thin sheets because of its inherently low ductility . As a result, Mg sheet is often produced at

Single point incremental forming: Formability of PC sheets

Science.gov (United States)

Formisano, A.; Boccarusso, L.; Carrino, L.; Lambiase, F.; Minutolo, F. Memola Capece

2018-05-01

Recent research on Single Point Incremental Forming of polymers has slightly covered the possibility of expanding the materials capability window of this flexible forming process beyond metals, by demonstrating the workability of thermoplastic polymers at room temperature. Given the different behaviour of polymers compared to metals, different aspects need to be deepened to better understand the behaviour of these materials when incrementally formed. Thus, the aim of the work is to investigate the formability of incrementally formed polycarbonate thin sheets. To this end, an experimental investigation at room temperature was conducted involving formability tests; varying wall angle cone and pyramid frusta were manufactured by processing polycarbonate sheets with different thicknesses and using tools with different diameters, in order to draw conclusions on the formability of polymer sheets through the evaluation of the forming angles and the observation of the failure mechanisms.

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.

Complete plasma dropouts at Vela satellites during thinning of the plasma sheet

International Nuclear Information System (INIS)

Lui, A.T.Y.; Hones, E.W. Jr.; Venkatesan, D.; Akasofu, S.; Bame, S.J.

1975-01-01

Five satellite years of Vela data are examined for plasma sheet thinnings. Complete proton disappearances (plasma dropouts) are the main subject here. During such times, the Vela satellite is temporarily in the high-latitude tail lobe. The distribution of such plasma dropouts within the magnetotail suggests that the semithickness of the plasma sheet near midnight seldom reaches less than 1 R/sub E/ during substorms and that the dawn and dusk portions of the plasma sheet remain thicker than the midnight portion. But it is also shown that the plasma sheet occasionally becomes very thin near the dusk magnetopause. No such severe thinnings of the plasma sheet are found near the dawn magnetopause. Plasma dropouts can occur regardless of the sign of the Z component of the IMF, but their frequency of occurrence seems to be greater when the Z component is negative.Three plasma dropouts which occurred in the midnight sector at unusually large distances from the estimated position of the neutral sheet were observed during geomagnetic storms. It is likely that the midnight sector of the plasma sheet can become very thick (approx.18 R/sub E/) at certain times during the main phase of storms. Detailed measurements in the plasma sheet were obtained near the beginning of a geomagnetic storm whose sc triggered a substorm. A compression of the plasma sheet at X/sub SM/approx. =-15 R/sub E/ occurred about 10 min after the sc onset at the earth and about 5 min after the start of plasma sheet thinning associated with the sc-related substorm. If compression-thinning of the plasma sheet initiated this substorm, the triggering action must have occurred earthward of X/sub SM/approx. =-15 R/sub E/

Investigation of Forming Performance of Laminated Steel Sheets Using Finite Element Analyses

International Nuclear Information System (INIS)

Liu Wenning; Sun Xin; Ruokolainen, Robert; Gayden Xiaohong

2007-01-01

Laminated steel sheets have been used in automotive structures for reducing in-cabin noise. However, due to the marked difference in material properties of the different laminated layers, integrating laminated steel parts into the manufacturing processes can be challenging. Especially, the behavior of laminated sheets during forming processes is very different from that of monolithic steel sheets. During the deep-draw forming process, large shear deformation and corresponding high interfacial stress may initiate and propagate interfacial cracks between the core polymer and the metal skin, hence degrading the performance of the laminated sheets. In this paper, the formability of the laminated steel sheets is investigated by means of numerical analysis. The goal of this work is to gain insight into the relationship between the individual properties of the laminated sheet layers and the corresponding formability of the laminated sheet as a whole, eventually leading to reliable design and successful forming process development of such materials. Finite element analyses of laminate sheet forming are presented. Effects of polymer core thickness and viscoelastic properties of the polymer core, as well as punching velocity, are also investigated

The elasto plastic fracture mechanics in ductile metal sheets

International Nuclear Information System (INIS)

Khan, M.A.; Malik, M.N.; Naeem, A.; Haq, A.U.; Atkins, A.G.

1999-01-01

The crack initiation of propagation in ductile metal sheets are caused by various micro and macro changes taking place due to material properties, applied loads, shape of the indenter (tool geometry) and the environmental conditions. These microstructural failures are directly related to the atomic bonding, crystal lattices, grain boundary status, material flaws in matrix, inhomogeneities and anisotropy in the metal sheets. The Elasto-Plastic related energy based equations are applied to these Rigid Plastic materials to determine the onset of fracture in metal forming. The combined stress and strain criterion of a critical plastic work per unit volume is no more considered as a universal ductile fracture criterion, rather a critical plastic work per unit volume dependence on all sort of stresses (hydrostatic) are the required features for the sheet metal failure (fracture). In this present study, crack initiation and propagation are related empirically with fracture toughness and the application of the theory in industry to save energy. (author)

Facile route for synthesis of mesoporous Cr2O3 sheet as anode materials for Li-ion batteries

International Nuclear Information System (INIS)

Cao, Zhiqin; Qin, Mingli; Jia, Baorui; Zhang, Lin; Wan, Qi; Wang, Mingshan; Volinsky, Alex A.; Qu, Xuanhui

2014-01-01

Mesoporous Cr 2 O 3 with a high specific surface area of 162 m 2 g −1 is prepared by the solution combustion method. The mesoporous Cr 2 O 3 has a sheet structure, which consists of nanoparticles with an average size of 20 nm. As an anode electrode material for rechargeable lithium-ion batteries, the mesoporous Cr 2 O 3 nanoparticles display enhanced electrochemical performance. Stable and reversible capacity of 480 mA h g −1 after 55 cycles is demonstrated. The enhanced electrochemical performance of the Cr 2 O 3 can be attributed to the high surface area and morphological characteristics of mesoporous materials

Studies of deformation-induced texture development in sheet materials using diffraction techniques

International Nuclear Information System (INIS)

Banovic, S.W.; Vaudin, M.D.; Gnaeupel-Herold, T.H.; Saylor, D.M.; Rodbell, K.P

2004-01-01

Crystallographic texture measurements were made on a series of rolled aluminum sheet specimens deformed in equi-biaxial tension up to a strain level of 0.11. The measurement techniques used were neutron diffraction with a 4-circle goniometer, electron backscatter diffraction, conventional powder X-ray diffraction (XRD), and XRD using an area detector. Results indicated a complex texture orientation distribution function which altered in response to the applied plastic deformation. Increased deformation caused the {1 1 0} planes, to align parallel to the plane of the sheet. The different techniques produced results that were very consistent with each other. The advantages and disadvantages of the various methods are discussed, with particular consideration of the time taken for each method, the range of orientation space accessible, the density of data that can be obtained, and the statistical significance of each data set with respect to rolled sheet product

Remember the periroot sheet in orthodontic treatment of ectodermal dysplasia patients

Directory of Open Access Journals (Sweden)

Izabella Vest Hansen

2014-01-01

Full Text Available Introduction: Root resorption has various etiologies. Recent studies have demonstrated a periroot sheet covering the root. The outermost layer of this sheet is the Malassez′ epithelial layer. Tooth malformations are seen in ectodermal dysplasia and it is believed that the ectodermal layer in the periroot sheet differs in cases of ectodermal dysplasia. Case reports: Three cases of unexpected severe root resorption are demonstrated. Two cases were diagnosed with ectodermal dysplasia and the third appeared with thin, curly hair and absence of eyebrows but no ectodermal diagnosis. In the ectodermal cases, there were severe orthodontically provoked resorptions on the teeth that appeared to be permanent but were possibly primary. In the third case, there was heavy resorption on permanent teeth due to orthodontic treatment. Discussion: The orthodontist should be aware that aggressive resorption can occur in cases not diagnosed with ectodermal dysplasia but with signs of ectodermal deviations, and that tooth morphology, hair, and skin are important to observe before proceeding with treatment.

Interlocking multi-material components made of structured steel sheets and high-pressure die cast aluminium

Science.gov (United States)

Senge, S.; Brachmann, J.; Hirt, G.; Bührig-Polaczek, A.

2017-10-01

Lightweight design is a major driving force of innovation, especially in the automotive industry. Using hybrid components made of two or more different materials is one approach to reduce the vehicles weight and decrease fuel consumption. As a possible way to increase the stiffness of multi-material components, this paper presents a process chain to produce such components made of steel sheets and high-pressure die cast aluminium. Prior to the casting sequence the steel sheets are structured in a modified rolling process which enables continuous interlocking with the aluminium. Two structures manufactured by this rolling process are tested. The first one is a channel like structure and the second one is a channel like structure with undercuts. These undercuts enable the formation of small anchors when the molten aluminium fills them. The correlation between thickness reduction during rolling and the shape of the resulting structure was evaluated for both structures. It can be stated that channels with a depth of up to 0.5 mm and a width of 1 mm could be created. Undercuts with different size depending on the thickness reduction could be realised. Subsequent aluminium high-pressure die casting experiments were performed to determine if the surface structure can be filled gap-free with molten aluminium during the casting sequence and if a gap-free connection can be achieved after contraction of the aluminium. The casting experiments showed that both structures could be filled during the high-pressure die casting. The channel like structure results in a gap between steel and aluminium after contraction of the cast metal whereas the structure with undercuts leads to a good interlocking resulting in a gap-free connection.

Ethanol Basics (Fact Sheet)

Energy Technology Data Exchange (ETDEWEB)

2015-01-01

Ethanol is a widely-used, domestically-produced renewable fuel made from corn and other plant materials. More than 96% of gasoline sold in the United States contains ethanol. Learn more about this alternative fuel in the Ethanol Basics Fact Sheet, produced by the U.S. Department of Energy's Clean Cities program.

Indirect Versus Direct Heating of Sheet Materials: Superplastic Forming and Diffusion Bonding Using Lasers

Science.gov (United States)

Jocelyn, Alan; Kar, Aravinda; Fanourakis, Alexander; Flower, Terence; Ackerman, Mike; Keevil, Allen; Way, Jerome

2010-06-01

Many from within manufacturing industry consider superplastic forming (SPF) to be ‘high tech’, but it is often criticized as too complicated, expensive, slow and, in general, an unstable process when compared to other methods of manipulating sheet materials. Perhaps, the fundamental cause of this negative perception of SPF, and also of diffusion bonding (DB), is the fact that the current process of SPF/DB relies on indirect sources of heating to produce the conditions necessary for the material to be formed. Thus, heat is usually derived from the electrically heated platens of hydraulic presses, to a lesser extent from within furnaces and, sometimes, from heaters imbedded in ceramic moulds. Recent evaluations of these isothermal methods suggest they are slow, thermally inefficient and inappropriate for the process. In contrast, direct heating of only the material to be formed by modern, electrically efficient, lasers could transform SPF/DB into the first choice of designers in aerospace, automotive, marine, medical, architecture and leisure industries. Furthermore, ‘variable temperature’ direct heating which, in theory, is possible with a laser beam(s) may provide a means to control material thickness distribution, a goal of enormous importance as fuel efficient, lightweight structures for transportation systems are universally sought. This paper compares, and contrasts, the two systems and suggests how a change to laser heating might be achieved.

High-speed blanking of copper alloy sheets: Material modeling and simulation

Science.gov (United States)

Husson, Ch.; Ahzi, S.; Daridon, L.

2006-08-01

To optimize the blanking process of thin copper sheets ( ≈ 1. mm thickness), it is necessary to study the influence of the process parameters such as the punch-die clearance and the wear of the punch and the die. For high stroke rates, the strain rate developed in the work-piece can be very high. Therefore, the material modeling must include the dynamic effects.For the modeling part, we propose an elastic-viscoplastic material model combined with a non-linear isotropic damage evolution law based on the theory of the continuum damage mechanics. Our proposed modeling is valid for a wide range of strain rates and temperatures. Finite Element simulations, using the commercial code ABAQUS/Explicit, of the blanking process are then conducted and the results are compared to the experimental investigations. The predicted cut edge of the blanked part and the punch-force displacement curves are discussed as function of the process parameters. The evolution of the shape errors (roll-over depth, fracture depth, shearing depth, and burr formation) as function of the punch-die clearance, the punch and the die wear, and the contact punch/die/blank-holder are presented. A discussion on the different stages of the blanking process as function of the processing parameters is given. The predicted results of the blanking dependence on strain-rate and temperature using our modeling are presented (for the plasticity and damage). The comparison our model results with the experimental ones shows a good agreement.

Determination of the forming limit diagram of zinc electro-galvanized steel sheets

Directory of Open Access Journals (Sweden)

W. Fracz

2012-04-01

Full Text Available Forming limit curves (FLC of deep drawing steel sheets have been determined experimentally and calculated on the base of the material tensile properties following the Hill, Swift, Marciniak-Kuczyński and Sing-Rao methods. Only the FLC modeled from a singly linear forming limit stress curve exhibits good consistence with experimental curve. It was established that a linearized limit stress locus describes adequately the actual localized neck conditions for the material chosen in this study. The quantitative X-ray microanalysis of the Fe contents in the sheet surface layer composition was used to determine cracking limit curve (CLC of electro-galvanized steel sheet. The change in zinc layer (and base sheet metal thickness was used as a criteria in calculation of the CLC.

Modelling of friction anisotropy of deepdrawing sheet in ABAQUS/EXPLICIT

Directory of Open Access Journals (Sweden)

F. Stachowicz

2010-07-01

Full Text Available This paper presents the experimental and numerical results of rectangular cup drawing of steel sheets. The aim of the experimental study was to analyze material behavior under deformation. The received results were further used to verify the results from numerical simulation by taking friction and material anisotropy into consideration. A 3D parametric finite element (FE model was built using the FE-package ABAQUS/Standard. ABAQUS allows analyzing physical models of real processes putting special emphasis on geometrical non-linearities caused by large deformations, material non-linearities and complex friction conditions. Frictional properties of the deep drawing quality steel sheet were determined by using the pin-on-disc tribometer. It shows that the friction coefficient value depends on the measured angle from the rolling direction and corresponds to the surface topography. A quadratic Hill anisotropic yield criterion was compared with Huber-Mises yield criterion having isotropic hardening. Plastic anisotropy is the result of the distortion of the yield surface shape due to the material microstructural state. The sensitivity of constitutive laws to the initial data characterizing material behavior isalso presented. It is found that plastic anisotropy of the matrix in ductile sheet metal has influence on deformation behavior of the material. If the material and friction anisotropy are taken into account in the finite element analysis, this approach undoubtedly gives the most approximate numerical results to real processes. This paper is the first part of the study of numerical investigation using ABAQUS and mainly deals with the most influencing parameters in a forming process to simulate the sheet metal forming of rectangular cup.

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.)

Machine Shop Suggested Job and Task Sheets. Part II. 21 Advanced Jobs.

Science.gov (United States)

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

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

Thermal properties of highly structured composite and aluminium sheets in an aerodynamic tunnel

Science.gov (United States)

Kulhavy, Petr; Egert, Josef

This article deals with the thermodynamic behaviour of heat shields - structured metal and composite plates. Experiments have been carried out in a wind tunnel with an additional heating, which simulates the heat source from engine or exhaust pipe and simultaneously the airflow generated during a car movement. The tested sheets with hexagonal structure were a standard commercial made of aluminium and a second manufactured by replication (lamination, diffusion) from glass fabric. The airflow in a parallel way along the sheets was analysed experimentally in order to determine the heat transfer efficiency between surfaces of sheets and surrounding airflow. The temperature on the sheets was chosen to observe the effects of different sheets material, various heat power and airflow velocity. During the experiment a thermal input below the sheets and airflow velocity through the tunnel have been changed. The thermal field distribution on the metal sheet is different than in case of composite sheet. For the composite material the thermal field distribution was more homogeneous. This article describe briefly also methods of obtaining real composite geometry based on scanned data and their reconstruction for using in some future numerical models.

Thermal properties of highly structured composite and aluminium sheets in an aerodynamic tunnel

Directory of Open Access Journals (Sweden)

Kulhavy Petr

2017-01-01

Full Text Available This article deals with the thermodynamic behaviour of heat shields - structured metal and composite plates. Experiments have been carried out in a wind tunnel with an additional heating, which simulates the heat source from engine or exhaust pipe and simultaneously the airflow generated during a car movement. The tested sheets with hexagonal structure were a standard commercial made of aluminium and a second manufactured by replication (lamination, diffusion from glass fabric. The airflow in a parallel way along the sheets was analysed experimentally in order to determine the heat transfer efficiency between surfaces of sheets and surrounding airflow. The temperature on the sheets was chosen to observe the effects of different sheets material, various heat power and airflow velocity. During the experiment a thermal input below the sheets and airflow velocity through the tunnel have been changed. The thermal field distribution on the metal sheet is different than in case of composite sheet. For the composite material the thermal field distribution was more homogeneous. This article describe briefly also methods of obtaining real composite geometry based on scanned data and their reconstruction for using in some future numerical models.

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

ENVIRONMENTAL AND ECONOMIC PROSPECTS FOR USAGE OF PULTRUDED COMPOSITE SHEET PILES

Directory of Open Access Journals (Sweden)

BURYA Alexander I.

2016-11-01

Full Text Available The article focuses on the description of pultruded composite sheet piles. The article covers the production technology, advantages over other traditional materials, as well as environmental and economic prospects for expanding of the usage of composite sheet piling.

SPR Characteristics Curve and Distribution of Residual Stress in Self-Piercing Riveted Joints of Steel Sheets

OpenAIRE

Haque, Rezwanul; Wong, Yat C.; Paradowska, Anna; Blacket, Stuart; Durandet, Yvonne

2017-01-01

Neutron diffraction was used to describe the residual stress distributions in self-piercing riveted (SPR) joints. The sheet material displayed a compressive residual stress near the joint, and the stress gradually became tensile in the sheet material far away from the joint. The stress in the rivet leg was lower in the thick joint of the softer steel sheet than in the thin joint of the harder steel sheet. This lower magnitude was attributed to the lower force gradient during the rivet flaring...

Novel Flexible Wearable Sensor Materials and Signal Processing for Vital Sign and Human Activity Monitoring.

Science.gov (United States)

Servati, Amir; Zou, Liang; Wang, Z Jane; Ko, Frank; Servati, Peyman

2017-07-13

Advances in flexible electronic materials and smart textile, along with broad availability of smart phones, cloud and wireless systems have empowered the wearable technologies for significant impact on future of digital and personalized healthcare as well as consumer electronics. However, challenges related to lack of accuracy, reliability, high power consumption, rigid or bulky form factor and difficulty in interpretation of data have limited their wide-scale application in these potential areas. As an important solution to these challenges, we present latest advances in novel flexible electronic materials and sensors that enable comfortable and conformable body interaction and potential for invisible integration within daily apparel. Advances in novel flexible materials and sensors are described for wearable monitoring of human vital signs including, body temperature, respiratory rate and heart rate, muscle movements and activity. We then present advances in signal processing focusing on motion and noise artifact removal, data mining and aspects of sensor fusion relevant to future clinical applications of wearable technology.

Multifunctional smart composites with integrated carbon nanotube yarn and sheet

Science.gov (United States)

Chauhan, Devika; Hou, Guangfeng; Ng, Vianessa; Chaudhary, Sumeet; Paine, Michael; Moinuddin, Khwaja; Rabiee, Massoud; Cahay, Marc; Lalley, Nicholas; Shanov, Vesselin; Mast, David; Liu, Yijun; Yin, Zhangzhang; Song, Yi; Schulz, Mark

2017-04-01

Multifunctional smart composites (MSCs) are materials that combine the good electrical and thermal conductivity, high tensile and shear strength, good impact toughness, and high stiffness properties of metals; the light weight and corrosion resistance properties of composites; and the sensing or actuation properties of smart materials. The basic concept for MSCs was first conceived by Daniel Inman and others about 25 years ago. Current laminated carbon and glass fiber polymeric composite materials have high tensile strength and are light in weight, but they still lack good electrical and thermal conductivity, and they are sensitive to delamination. Carbon nanotube yarn and sheets are lightweight, electrically and thermally conductive materials that can be integrated into laminated composite materials to form MSCs. This paper describes the manufacturing of high quality carbon nanotube yarn and sheet used to form MSCs, and integrating the nanotube yarn and sheet into composites at low volume fractions. Various up and coming technical applications of MSCs are discussed including composite toughening for impact and delamination resistance; structural health monitoring; and structural power conduction. The global carbon nanotube overall market size is estimated to grow from 2 Billion in 2015 to 5 Billion by 2020 at a CAGR of 20%. Nanotube yarn and sheet products are predicted to be used in aircraft, wind machines, automobiles, electric machines, textiles, acoustic attenuators, light absorption, electrical wire, sporting equipment, tires, athletic apparel, thermoelectric devices, biomedical devices, lightweight transformers, and electromagnets. In the future, due to the high maximum current density of nanotube conductors, nanotube electromagnetic devices may also become competitive with traditional smart materials in terms of power density.

A Novel 2D Porous Print Fabric-like α-Fe_2O_3 Sheet with High Performance as the Anode Material for Lithium-ion Battery

International Nuclear Information System (INIS)

Zhang, Suyue; Zhang, Peigen; Xie, Anjian; Li, Shikuo; Huang, Fangzhi; Shen, Yuhua

2016-01-01

Anode materials are very crucial in lithium ion batteries. Exploring the simple and low cost production of anodes with excellent electrochemical performance remains a great challenge. Here, we used natural flower spikes of Typha orientalis as the bio-templates and organizers to prepare a novel two-dimensional (2D) porous print fabric-like α-Fe_2O_3 sheet with thickness of about 30 nm. The prepared large-area sheets were orderly assembled by many nanosheets or nanoparticles, and two kinds of pore structures, such as pores with average diameter of about 50 nm or pore channels with aspect ratio of ca. 4, presented between adjacent nanosheets. The pre-treatment by ammonium for flower spikes has a great effect on the microstructure and electrochemical performance of the products. As the anode material for lithium ion battery (LIB), the as-obtained porous print fabric-like α-Fe_2O_3 sheets show an initial discharge capacity of 2264 mA h g"−"1 and the specific capacity of 1028 mA h g"−"1 after 100 cycles at a current density of 500 mA g"−"1, which is higher than the theoretical capacity of α-Fe_2O_3 (1007 mA h g"−"1). This highly reversible capacity is attributed to the very thin large-area sheet structure, and many pores or pore channels among the interconnected nanosheets, which could increase lithium-ion mobility, facilitate the transport of electrons and shorten the distance for Li"+ diffusion, and also buffer large volume changes of the anodes during lithium insertion and extraction at the same time. The synthesis process is very simple, providing a low-cost production approach toward high-performance energy storage materials.

Probabilistic Design in a Sheet Metal Stamping Process under Failure Analysis

International Nuclear Information System (INIS)

Buranathiti, Thaweepat; Cao, Jian; Chen, Wei; Xia, Z. Cedric

2005-01-01

Sheet metal stamping processes have been widely implemented in many industries due to its repeatability and productivity. In general, the simulations for a sheet metal forming process involve nonlinearity, complex material behavior and tool-material interaction. Instabilities in terms of tearing and wrinkling are major concerns in many sheet metal stamping processes. In this work, a sheet metal stamping process of a mild steel for a wheelhouse used in automobile industry is studied by using an explicit nonlinear finite element code and incorporating failure analysis (tearing and wrinkling) and design under uncertainty. Margins of tearing and wrinkling are quantitatively defined via stress-based criteria for system-level design. The forming process utilizes drawbeads instead of using the blank holder force to restrain the blank. The main parameters of interest in this work are friction conditions, drawbead configurations, sheet metal properties, and numerical errors. A robust design model is created to conduct a probabilistic design, which is made possible for this complex engineering process via an efficient uncertainty propagation technique. The method called the weighted three-point-based method estimates the statistical characteristics (mean and variance) of the responses of interest (margins of failures), and provide a systematic approach in designing a sheet metal forming process under the framework of design under uncertainty

Forming properties and springback evaluation of copper beryllium sheets

International Nuclear Information System (INIS)

Tseng, A.A.; Jen, K.P.; Chen, T.C.; Kondetimmamhalli, R.

1995-01-01

Copper beryllium (CuBe) alloys possess excellent strength and conductivity. They have become the most important materials used for producing high reliability connectors and interconnections for electrical and electronic applications. As demand for high connection density in electrical and electronic products grows, springback behaviors become increasingly critical in fabricating these miniaturized contact components from sheet base materials. In the present article, a study of the springback behavior of CuBe sheets under different heat treatments is presented, with the goal of providing reliable information needed for fabricating more intricate connection parts. Both experimental and analytical techniques were adopted. The tensile tester was first used to study the springback related tensile properties. The governing tensile parameters on springback were identified, and their variations for sheets with different heat treatments were studied. It was found that a bilinear constitutive relationship can be characterize the stress strain behavior of the CuBe alloy. A closed form solution based on this bilinear relationship was formulated to predict the springback for the CuBe sheets at bending conditions. A V-shaped bend tester having an interchangeable punch to accommodate multiple radii was designed and built to evaluate the springback properties of CuBe sheets. A good correlation was found between the analytical predictions and experimental data. A parametric study, as an example, was also performed to provide the springback information needed for designing complicated connectors

Name signs in Danish Sign Language

DEFF Research Database (Denmark)

Bakken Jepsen, Julie

2018-01-01

in spoken languages, where a person working as a blacksmith by his friends might be referred to as ‘The Blacksmith’ (‘Here comes the Blacksmith!’) instead of using the person’s first name. Name signs are found not only in Danish Sign Language (DSL) but in most, if not all, sign languages studied to date....... This article provides examples of the creativity of the users of Danish Sign Language, including some of the processes in the use of metaphors, visual motivation and influence from Danish when name signs are created.......A name sign is a personal sign assigned to deaf, hearing impaired and hearing persons who enter the deaf community. The mouth action accompanying the sign reproduces all or part of the formal first name that the person has received by baptism or naming. Name signs can be compared to nicknames...

Nanostructure characterization of beta-sheet crystals in silk under various temperatures

Directory of Open Access Journals (Sweden)

Zhang Yan

2014-01-01

Full Text Available This paper studies the nanostructure characterizations of β-sheet in silk fiber with different reaction temperatures. A molecular dynamic model is developed and simulated by Gromacs software packages. The results reveal the change rules of the number of hydrogen bonds in β-sheet under different temperatures. The best reaction temperature for the β-sheet crystals is also found. This work provides theoretical basis for the designing of materials based on silk.

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.)

On the System of Person-Denoting Signs in Estonian Sign Language: Estonian Name Signs

Science.gov (United States)

Paales, Liina

2010-01-01

This article discusses Estonian personal name signs. According to study there are four personal name sign categories in Estonian Sign Language: (1) arbitrary name signs; (2) descriptive name signs; (3) initialized-descriptive name signs; (4) loan/borrowed name signs. Mostly there are represented descriptive and borrowed personal name signs among…

Sinus cut-off sign: A helpful sign in the CT diagnosis of diaphragmatic rupture associated with pleural effusion

International Nuclear Information System (INIS)

Kaya, Seyda Ors; Karabulut, Nevzat; Yuncu, Gokhan; Sevinc, Serpil; Kiroglu, Yilmaz

2006-01-01

The objective of our study was to describe the 'sinus cut-off' sign at CT in the diagnosis of diaphragmatic rupture in patients with blunt abdominal trauma complicated with pleural effusion, and evaluate its utility in an experimental model. Between January 2004 and March 2005, we observed an unusual interruption of costophrenic sinus at CT in three patients with blunt abdominal trauma accompanied with pleural effusion. This observation prompted us to evaluate the utility of this sign in an experimental model. Laparotomically, we created 2 cm diapragmatic lacerations at each hemidiaphragm in two rabbits and pushed up the abdominal viscera with omentum through the defect. To simulate hemothorax, we also injected 5-10 mL of diluted contrast material into the pleural space. Using a dual-slice helical CT scanner, limited thoracoabdominal CT examination was performed before and after injection of intrapleural contrast material. The images were analyzed for the presence of CT signs for diaphragmatic injury. The left posterior costophrenic sulcus was interrupted in all of the three patients with left pleural effusion. While it was associated with other findings of diaphragmatic injury, the 'sinus cut-off sign' was the sole finding in one patient. The sinus cut-off sign was observed on the CT scans of 100% of the rabbits with a left and right sided diaphragmatic rupture. The 'sinus cut-off sign' is useful and can increase the CT detection of acute diaphragmatic injury associated with pleural effusion

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.

Chemical and radiation stability of SuperLig reg-sign 644, resorcinol-formaldehyde, and CS-100 cesium ion exchange materials

International Nuclear Information System (INIS)

Brown, G.N.; Adami, S.R.; Bray, L.A.

1995-09-01

At the request of the Initial Pretreatment Module Project within Westinghouse Hanford Company, Pacific Northwest Laboratory (PNL) conducted this study for the Efficient Separations and Processing Crosscutting Program (ESP) under the task ''Develop and Test Sorbents.'' The purpose of the study was to assess and compare the chemical and radiolytic stability of several cesium-selective ion exchange materials in simulated alkaline Hanford tank waste matrices. Pretreatment of nuclear process wastes to remove of cesium and other radionuclides by ion exchange was proposed previously as one method of minimizing the amount of high-level radioactive waste at Hanford. In this study, PNL evaluated three cesium-selective materials SuperLig reg-sign 644, resorcinol-formaldehyde (R-F), and CS-100 for chemical and radiation stability in 1 M NaOH and a simulated neutralized current acid waste (NCAW). The objective of the study is to investigate the stability of the newly produced SuperLig reg-sign 644 under a variety of conditions in an attempt to simulate and predict the degradation process. The following specific conclusions and recommendations resulted from the study

Chemical and radiation stability of SuperLig{reg_sign}644, resorcinol-formaldehyde, and CS-100 cesium ion exchange materials

Energy Technology Data Exchange (ETDEWEB)

Brown, G.N.; Adami, S.R.; Bray, L.A. [and others

1995-09-01

At the request of the Initial Pretreatment Module Project within Westinghouse Hanford Company, Pacific Northwest Laboratory (PNL) conducted this study for the Efficient Separations and Processing Crosscutting Program (ESP) under the task ``Develop and Test Sorbents.`` The purpose of the study was to assess and compare the chemical and radiolytic stability of several cesium-selective ion exchange materials in simulated alkaline Hanford tank waste matrices. Pretreatment of nuclear process wastes to remove of cesium and other radionuclides by ion exchange was proposed previously as one method of minimizing the amount of high-level radioactive waste at Hanford. In this study, PNL evaluated three cesium-selective materials SuperLig{reg_sign}644, resorcinol-formaldehyde (R-F), and CS-100 for chemical and radiation stability in 1 M NaOH and a simulated neutralized current acid waste (NCAW). The objective of the study is to investigate the stability of the newly produced SuperLig{reg_sign}644 under a variety of conditions in an attempt to simulate and predict the degradation process. The following specific conclusions and recommendations resulted from the study.

FY 1998 results of the regional consortium R and D project/the venture promotion type regional consortium R and D (small-/medium-size venture creation type). Development of multilayer functional materials (Development of health sheets); 1998 nendo tasekiso kino zairyo no kaihatsu (kenko sheet no kaihatsu) seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

The R and D were conducted with the aim of developing multilayer functional materials (health sheets) relating to the bedding which fit the human skin. The study was made on the following: production/processing method to control shapes of new materials made from abrasive grain, powder mixing technology to improve functions, development of nonwoven fabrics with flexibility, water absorbability, compressibility, durability, thermal processability, etc. As a result, multilayer functional materials were obtained by combining functions which the nonwoven fabric and alumina-based abrasive grain have. By further pulverizing the alumina-based abrasive grain, the far infrared radiation function was improved, and at the same time the color variation was also made possible by selection of raw materials. In the fabrication of nonwoven fabrics, raw materials of rayon, polyester, acrylic fiber, etc. were selected, and soft composite nonwoven sheets were obtained by building three- to five-layer and by intermittent water jet processing. Moreover, an assessment method using KES feeling measuring system was established. (NEDO)

2D sandwich-like sheets of iron oxide grown on graphene as high energy anode material for supercapacitors.

Science.gov (United States)

Qu, Qunting; Yang, Shubin; Feng, Xinliang

2011-12-08

2D sandwich-like sheets of iron oxide grown on graphene as high energy anode material for supercapacitors are prepared from the direct growth of FeOOH nanorods on the surface of graphene and the subsequent electrochemical transformation of FeOOH to Fe(3)O(4). The Fe(3)O(4) @RGO nanocomposites exhibit superior capacitance (326 F g(-1)), high energy density (85 Wh kg(-1)), large power, and good cycling performance in 1 mol L(-1) LiOH solution. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electro-thermo-mechanical coupling analysis of deep drawing with resistance heating for aluminum matrix composites sheet

Science.gov (United States)

Zhang, Kaifeng; Zhang, Tuoda; Wang, Bo

2013-05-01

Recently, electro-plastic forming to be a focus of attention in materials hot processing research area, because it is a sort of energy-saving, high efficient and green manufacturing technology. An electro-thermo-mechanical model can be adopted to carry out the sequence simulation of aluminum matrix composites sheet deep drawing via electro-thermal coupling and thermal-mechanical coupling method. The first step of process is resistance heating of sheet, then turn off the power, and the second step is deep drawing. Temperature distribution of SiCp/2024Al composite sheet by resistance heating and sheet deep drawing deformation were analyzed. During the simulation, effect of contact resistances, temperature coefficient of resistance for electrode material and SiCp/2024Al composite on temperature distribution were integrally considered. The simulation results demonstrate that Sicp/2024Al composite sheet can be rapidly heated to 400° in 30s using resistances heating and the sheet temperature can be controlled by adjusting the current density. Physical properties of the electrode materials can significantly affect the composite sheet temperature distribution. The temperature difference between the center and the side of the sheet is proportional to the thermal conductivity of the electrode, the principal cause of which is that the heat transfers from the sheet to the electrode. SiCp/2024Al thin-wall part can be intactly manufactured at strain rate of 0.08s-1 and the sheet thickness thinning rate is limited within 20%, which corresponds well to the experimental result.

Method of preventing contaminations in radioactive material handling facilities

International Nuclear Information System (INIS)

Inoue, Shunji.

1986-01-01

Purpose: To prevent the contamination on the floor surface of working places by laying polyvinyl butyral sheets over the floor surface, replacing when the sheets are contaminated, followed by burning. Method: Polyvinyl butyral sheets comprising 50 - 70 mol% of butyral component are laid in a radioactive material handling facility, radioactive materials are handled on the polyvinyl butyral sheets and the sheets are replaced when contaminated. The polyvinyl butyral sheets used contain 62 - 68 mol% of butyral component and has 0.03 - 0.2 mm thickness. The contaminated sheets are subjected to burning processing. This can surely collect radioactive materials and the sheets have favorable burnability, releasing no corrosive or deleterious gases. In addition, they are inexpensive and give no hindrance to the workers walking. (Takahashi, M.)

Energy-Based Yield Criteria for Orthotropic Materials, Exhibiting Strength-Differential Effect. Specification for Sheets under Plane Stress State

Directory of Open Access Journals (Sweden)

Szeptyński P.

2017-06-01

Full Text Available A general proposition of an energy-based limit condition for anisotropic materials exhibiting strength-differential effect (SDE based on spectral decomposition of elasticity tensors and the use of scaling pressure-dependent functions is specified for the case of orthotropic materials. A detailed algorithm (based on classical solutions of cubic equations for the determination of elastic eigenstates and eigenvalues of the orthotropic stiffness tensor is presented. A yield condition is formulated for both two-dimensional and three-dimensional cases. Explicit formulas based on simple strength tests are derived for parameters of criterion in the plane case. The application of both criteria for the description of yielding and plastic deformation of metal sheets is discussed in detail. The plane case criterion is verified with experimental results from the literature.

Lateral dimension-dependent antibacterial activity of graphene oxide sheets.

Science.gov (United States)

Liu, Shaobin; Hu, Ming; Zeng, Tingying Helen; Wu, Ran; Jiang, Rongrong; Wei, Jun; Wang, Liang; Kong, Jing; Chen, Yuan

2012-08-21

Graphene oxide (GO) is a promising precursor to produce graphene-family nanomaterials for various applications. Their potential health and environmental impacts need a good understanding of their cellular interactions. Many factors may influence their biological interactions with cells, and the lateral dimension of GO sheets is one of the most relevant material properties. In this study, a model bacterium, Escherichia coli ( E. coli ), was used to evaluate the antibacterial activity of well-dispersed GO sheets, whose lateral size differs by more than 100 times. Our results show that the antibacterial activity of GO sheets toward E. coli cells is lateral size dependent. Larger GO sheets show stronger antibacterial activity than do smaller ones, and they have different time- and concentration-dependent antibacterial activities. Large GO sheets lead to most cell loss after 1 h incubation, and their concentration strongly influences antibacterial activity at relative low concentration (oxidation capacity toward glutathione is similar, consistent with X-ray photoelectron spectroscopy and ultraviolet-visible absorption spectroscopy results. This suggests the lateral size-dependent antibacterial activity of GO sheets is caused by neither their aggregation states, nor oxidation capacity. Atomic force microscope analysis of GO sheets and cells shows that GO sheets interact strongly with cells. Large GO sheets more easily cover cells, and cells cannot proliferate once fully covered, resulting in the cell viability loss observed in the followed colony counting test. In contrast, small GO sheets adhere to the bacterial surfaces, which cannot effectively isolate cells from environment. This study highlights the importance of tailoring the lateral dimension of GO sheets to optimize the application potential with minimal risks for environmental health and safety.

"I Am the Book"--Deaf Poets' Views on Signed Poetry

Science.gov (United States)

Sutton-Spence, Rachel; de Quadros, Ronice Müller

2014-01-01

Despite research commenting on and analyzing signed poetry, there is little research exploring the aims and intentions of the signing poets. This paper considers the producers of signed poetry, rather than their products. Using material gathered from interviews with three established signing deaf poets, we consider what they hope to achieve when…

Aluminium sheet forming at elevated temperatures

NARCIS (Netherlands)

van den Boogaard, Antonius H.; Bolt, P.J.; Werkhoven, R.J.

2001-01-01

The formability of aluminum sheet depends on the temperature of the material and the strain rate. E.g. the limiting drawing ratio can be improved by increasing the temperature uniformly, but even more by heating the flange and cooling the punch. To accurately simulate the deep drawing or stretching

Multi-scale contact modeling of coated steels for sheet metal forming applications

NARCIS (Netherlands)

Shisode, Meghshyam; Hazrati Marangalou, Javad; Mishra, Tanmaya; De Rooij, Matthijn; Van Den Boogaard, Ton; Bay, Niels; Nielsen, Chris V.

2018-01-01

Friction in sheet metal forming is a local phenomenon which depends on continuously evolving contact conditions during the forming process. This is mainly influenced by local contact pressure, surface textures of the sheet metal as well as the forming tool surface profile and material behavior. The

Synthesis of Boron Nano wires, Nano tubes, and Nano sheets

International Nuclear Information System (INIS)

Patel, R.B.; Chou, T.; Iqbal, Z.

2014-01-01

The synthesis of boron nano wires, nano tubes, and nano sheets using a thermal vapor deposition process is reported. This work confirms previous research and provides a new method capable of synthesizing boron nano materials. The materials were made by using various combinations of MgB 2 , Mg(BH 4 ) 2 , MCM-41, NiB, and Fe wire. Unlike previously reported methods, a nanoparticle catalyst and a silicate substrate are not required for synthesis. Two types of boron nano wires, boron nano tubes, and boron nano sheets were made. Their morphology and chemical composition were determined through the use of scanning electron microscopy, transmission electron microscopy, and electron energy loss spectroscopy. These boron-based materials have potential for electronic and hydrogen storage applications.

Root resorption: Focus on signs and symptoms of importance for avoiding root resorption during orthodontic treatment

Directory of Open Access Journals (Sweden)

Inger Kjaer

2014-01-01

Full Text Available Introduction: This paper summarizes the different conditions, which have a well-known influence on the resorption of tooth roots, exemplified by trauma and orthodontic treatment. The concept of the paper is to summarize and explain symptoms and signs of importance for avoiding resorption during orthodontic treatment. The Hypothesis: The hypothesis in this paper is that three different tissue layers covering the root in the so-called periroot sheet can explain signs and symptoms of importance for avoiding root resorption during orthodontic treatment. These different tissue layers are; outermost - an ectodermal tissue layer (Malassez′s epithelium, a middle layer - composed by the collagen-mesodermal tissue layer, and an innermost root-close innervation layer. Abnormalities in one of these tissue layers are thought to cause inflammatory processes in the periodontal membrane comparable to inflammatory processes provoked by trauma and orthodontic pressure. Inflammatory reactions are followed by resorptive processes in the periroot sheet and along the root surface. Evaluation of the Hypothesis: Different morphologies in the dentition are signs of abnormal epithelium or an abnormal mesodermal layer. It has formerly been demonstrated how demyelinization of the myelin sheaths in the peripheral nerves close to the root provoke resorption. Accordingly, conditions affecting these tissue layers can be associated not only with different morphologies but also with general symptoms and diseases (e.g., ectodermal dysplasia and hypophosphatasia.

Behavior of sheet-like crystalline ammonium trivanadate hemihydrate (NH4V3O8×0.5H2O) as a novel ammonia sensing material

International Nuclear Information System (INIS)

Leonardi, S.G.; Primerano, P.; Donato, N.; Neri, G.

2013-01-01

This work reports the use of ammonium trivanadate hemihydrate (NH 4 V 3 O 8 ×0.5H 2 O) as a novel sensing material for ammonia resistive sensors. It was prepared by a simple and fast hydrothermal method from V 2 O 5 as a precursor and characterized by SEM, FT-IR, XRD and TG techniques. The as-synthesized material showed a sheet-like morphology and was found thermally stable up to 250–280 °C. It reacted promptly and irreversibly when exposed to ammonia at room temperature. A full reversibility was instead registered undergoing the formed ammonia adduct at a temperature higher than 200 °C. A NH 4 V 3 O 8 ×0.5H 2 O-based resistive gas sensor was fabricated and its sensing properties were evaluated. Experimental results obtained have given a preliminary demonstration of the feasibility of using NH 4 V 3 O 8 ×0.5H 2 O as a novel ammonia sensing material since it yields several advantages including easy synthesis of the sensing layer, good sensitivity and reproducibility and fast response. - Graphical abstract: Sheet-like morphology of the synthesized trivanadate hemihydrate (NH 4 V 3 O 8 ×0.5H 2 O). Inset: Its electrical response to different ammonia concentrations in air. - Highlights: • A simple hydrothermal method for the fast synthesis of trivanadate hemihydrate (NH 4 V 3 O 8 ×0.5H 2 O) is reported. • Sheet particles could be obtained. • A preliminary demonstration of the feasibility of using NH 4 V 3 O 8 ×0.5H 2 O as a novel ammonia sensing material is presented

Mechanical characterization and constitutive modeling of Mg alloy sheets

International Nuclear Information System (INIS)

Mekonen, M. Nebebe; Steglich, D.; Bohlen, J.; Letzig, D.; Mosler, J.

2012-01-01

Highlights: ► Material characterization of the Mg alloys AZ31 and ZE10 at elevated temperatures. ► Distortion of the yield locus does not depend on the strain rate. ► Novel constitutive model suitable for the analysis of sheet forming of magnesium. ► Strain-dependent r-values are included within the model. ► The model is thermodynamically consistent and accounts for distortional hardening. - Abstract: In this paper, an experimental mechanical characterization of the magnesium alloys ZE10 and AZ31 is performed and a suitable constitutive model is established. The mechanical characterization is based on uniaxial tensile tests. In order to avoid poor formability at room temperature, the tests were conducted at elevated temperature (200 °C). The uniaxial tensile tests reveal sufficient ductility allowing sheet forming processes at this temperature. The differences in yield stresses and plastic strain ratios (r-values) confirm the anisotropic response of the materials under study. The constitutive model is established so that the characteristic mechanical features observed in magnesium alloys such as anisotropy and compression-tension asymmetry can be accommodated. This model is thermodynamically consistent, incorporates rate effect, is formulated based on finite strain plasticity theory and is applicable in sheet forming simulations of magnesium alloys. More precisely, a model originally proposed by Cazacu and Barlat in 2004 and later modified to account for the evolution of the material anisotropy is rewritten in a thermodynamically consistent framework. The calibrated constitutive model is shown to capture the characteristic mechanical features observed in magnesium alloy sheets.

New technology for the production of magnesium strips and sheets

Directory of Open Access Journals (Sweden)

R. Kawalla

2008-07-01

Full Text Available A new production technology for magnesium strip, based on twin-roll-casting and strip rolling was developed in Freiberg Germany. By means of this economic method it is possible to produce strips in deep drawing quality with good forming properties in order to satisfy the request for low cost Mg sheets in the automotive and electronic industry. Both, coils as single sheets, were manufactured and rolled to a thickness of 1mm(0,5 mm. The technology of the new process and the properties of the twin-roll-casted material and the final sheets are presented.

A paper sheet phantom for scintigraphic planar imaging. Usefulness of pouch-laminated paper source

International Nuclear Information System (INIS)

Takaki, Akihiro; Soma, Tsutomu; Murase, Kenya; Teraoka, Satomi; Murakami, Tomonori; Kojima, Akihiro; Matsumoto, Masanori

2007-01-01

In order to perform experimental measurements for evaluation of imaging device's performance, data acquisition technique, and clinical images on scintigraphic imaging, many kinds of phantoms are employed. However, since these materials are acrylic and plastic, the thickness and quality of those materials cause attenuation and scatter in itself. We developed a paper sheet phantom sealed with a pouch laminator, which can be a true radioactive source in air. In this study, the paper sheet phantom was compared to the acrylic liver phantom, with the thickness of 2 cm, which is commercially available. The results showed that although some scatter counts were contained within the image of the acrylic liver phantom, there were few scattered photons in the paper sheet phantom image. Furthermore, this laminated paper sheet phantom made handling of the source and its waste easier. If the paper sheet phantom will be designed more sophisticatedly, it becomes a useful tool for planar imaging experiments. (author)

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

Constraints on Negative Prefixation in Polish Sign Language.

Science.gov (United States)

Tomaszewski, Piotr

2015-01-01

The aim of this article is to describe a negative prefix, NEG-, in Polish Sign Language (PJM) which appears to be indigenous to the language. This is of interest given the relative rarity of prefixes in sign languages. Prefixed PJM signs were analyzed on the basis of both a corpus of texts signed by 15 deaf PJM users who are either native or near-native signers, and material including a specified range of prefixed signs as demonstrated by native signers in dictionary form (i.e. signs produced in isolation, not as part of phrases or sentences). In order to define the morphological rules behind prefixation on both the phonological and morphological levels, native PJM users were consulted for their expertise. The research results can enrich models for describing processes of grammaticalization in the context of the visual-gestural modality that forms the basis for sign language structure.

Biscrolling nanotube sheets and functional guests into yarns.

Science.gov (United States)

Lima, Márcio D; Fang, Shaoli; Lepró, Xavier; Lewis, Chihye; Ovalle-Robles, Raquel; Carretero-González, Javier; Castillo-Martínez, Elizabeth; Kozlov, Mikhail E; Oh, Jiyoung; Rawat, Neema; Haines, Carter S; Haque, Mohammad H; Aare, Vaishnavi; Stoughton, Stephanie; Zakhidov, Anvar A; Baughman, Ray H

2011-01-07

Multifunctional applications of textiles have been limited by the inability to spin important materials into yarns. Generically applicable methods are demonstrated for producing weavable yarns comprising up to 95 weight percent of otherwise unspinnable particulate or nanofiber powders that remain highly functional. Scrolled 50-nanometer-thick carbon nanotube sheets confine these powders in the galleries of irregular scroll sacks whose observed complex structures are related to twist-dependent extension of Archimedean spirals, Fermat spirals, or spiral pairs into scrolls. The strength and electronic connectivity of a small weight fraction of scrolled carbon nanotube sheet enables yarn weaving, sewing, knotting, braiding, and charge collection. This technology is used to make yarns of superconductors, lithium-ion battery materials, graphene ribbons, catalytic nanofibers for fuel cells, and titanium dioxide for photocatalysis.

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)

Numerical simulation of the hole-flanging process for steel-polymer sandwich sheets

Science.gov (United States)

Griesel, Dominic; Keller, Marco C.; Groche, Peter

2018-05-01

In light of increasing demand for lightweight structures, hybrid materials are frequently used in load-optimized parts. Sandwich structures like metal-polymer sandwich sheets provide equal bending stiffness as their monolithic counterparts at a drastically reduced weight. In addition, sandwich sheets have noise-damping properties, thus they are well-suited for a large variety of parts, e.g. façade and car body panels, but also load-carrying components. However, due to the creep tendency and low heat resistance of the polymer cores, conventional joining technologies are only applicable to a limited degree. Through hole-flanging it is possible to create branches in sandwich sheets to be used as reinforced joints. While it is state of the art for monolithic materials, hole-flanging of sandwich sheets has not been investigated yet. In order to simulate this process for different material combinations and tool geometries, an axisymmetric model has been developed in the FE software Abaqus/CAE. In the present paper, various modeling strategies for steel-polymer sandwich sheets are examined, including volume elements, shell elements and combinations thereof. Different methods for joining the distinct layers in the FE model are discussed. By comparison with CT scans and optical 3D measurements of experimentally produced hole-flanges, the feasibility of the presented models is evaluated. Although a good agreement of the numerical and experimental results has been achieved, it becomes clear that the classical forming limit diagram (FLD) does not adequately predict failure of the steel skins.

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.

2D sandwich-like sheets of iron oxide grown on graphene as high energy anode material for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Qu, Qunting; Feng, Xinliang [College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 (China); Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); Yang, Shubin [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany)

2011-12-08

2D sandwich-like sheets of iron oxide grown on graphene as high energy anode material for supercapacitors are prepared from the direct growth of FeOOH nanorods on the surface of graphene and the subsequent electrochemical transformation of FeOOH to Fe{sub 3}O{sub 4}. The Fe{sub 3}O{sub 4} rate at RGO nanocomposites exhibit superior capacitance (326 F g{sup -1}), high energy density (85 Wh kg{sup -1}), large power, and good cycling performance in 1 mol L{sup -1} LiOH solution. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Research on Computer Integrated Manufacturing of Sheet Metal Parts for Lithium Battery

Directory of Open Access Journals (Sweden)

Pan Wei-Min

2016-01-01

Full Text Available Lithium battery has been widely used as the main driving force of the new energy vehicle in recent years. Sheet metal parts are formed by means of pressure forming techniques with the characteristics of light weight, small size and high structural strength. The sheet metal forming has higher productivity and material utilization than the mechanical cutting, therefore sheet metal parts are widely used in many fields, such as modern automotive industry, aviation, aerospace, machine tools, instruments and household appliances. In this paper, taking a complex lithium battery box as an example, the integrated manufacturing of sheet metal parts is studied, and the digital integrated design and manufacturing process system is proposed. The technology is studied such as sheet metal design, unfolding, sheet nesting and laser cutting, CNC turret punch stamping programming, CNC bending etc. The feasibility of the method is verified through the examples of products and the integrated manufacturing of sheet metal box is completed.

Feature Size Effect on Formability of Multilayer Metal Composite Sheets under Microscale Laser Flexible Forming

Directory of Open Access Journals (Sweden)

Huixia Liu

2017-07-01

Full Text Available Multilayer metal composite sheets possess superior properties to monolithic metal sheets, and formability is different from monolithic metal sheets. In this research, the feature size effect on formability of multilayer metal composite sheets under microscale laser flexible forming was studied by experiment. Two-layer copper/nickel composite sheets were selected as experimental materials. Five types of micro molds with different diameters were utilized. The formability of materials was evaluated by forming depth, thickness thinning, surface quality, and micro-hardness distribution. The research results showed that the formability of two-layer copper/nickel composite sheets was strongly influenced by feature size. With feature size increasing, the effect of layer stacking sequence on forming depth, thickness thinning ratio, and surface roughness became increasingly larger. However, the normalized forming depth, thickness thinning ratio, surface roughness, and micro-hardness of the formed components under the same layer stacking sequence first increased and then decreased with increasing feature size. The deformation behavior of copper/nickel composite sheets was determined by the external layer. The deformation extent was larger when the copper layer was set as the external layer.

Diet discussion begins for signing convention on physical protection

International Nuclear Information System (INIS)

Anon.

1988-01-01

As a part of the amendment of the domestic laws required for signing the 'Convention on the Physical Protection of Nuclear Materials', the government placed the bill for the partial amendment of the 'Law for the Regulations of Nuclear Source Materials, Nuclear Fuel Materials and Reactors' to the current session of the Diet, following the formal approval by the Cabinet on March 11. This bill provides for punishment in the case of endangering or threat related to the handling and use of nuclear materials. The Atomic Energy Commission proposed in December, last year the early signing of the Convention and the legislation on the antiterrorism and physical protection measures required for the signing. The amendment consists mainly of two parts: one stipulates the obligation for those who manage the handling of nuclear materials to take the proper measures for their physical protection, and the other stipulates the punishment of the crimes related to nuclear materials. Regarding the other amendment of the relevant domestic laws, the Criminal Law was partially amended in June, last year. The Aviation Act and the Ships Safety Act, both related to the transport of nuclear materials, will not be amended, but only the relevant Ministerial Ordinances will be revised. The Convention on the Physical Protection of Nuclear Materials came into force in February, 1987, and consists of 23 articles. (Kako, I.)

Tribo-systems for Sheet Metal Forming

DEFF Research Database (Denmark)

Bay, Niels

2009-01-01

The present paper gives an overview of more than 10 years work by the author’s research group through participation in national as well as international framework programmes on developing and testing environmentally friendly lubricants and tool materials and coatings inhibiting galling. Partners ......’s research group has especially been involved in the development of a system of tribo-tests for sheet metal forming and in testing and modelling of friction and limits of lubrication of new, environmentally friendly lubricants and tool materials....

Quantitative Analysis of Graphene Sheet Content in Wood Char Powders during Catalytic Pyrolysis

Institute of Scientific and Technical Information of China (English)

Yan-Jia Liou; Wu-Jang Huang

2013-01-01

The quantitative characterization of the graphene sheet content in carbon-containing materials is arguable and has not yet been developed.The authors report on a feasible method to characterize graphene sheet content quantitatively in pyrolized carbon materials using an X-ray diffraction (XRD) spectrometer.A direct carbonation at 300 ℃ followed by catalytic pyrolysis (heat-treatment temperature was set at 700-1400 ℃)under a vacuum condition was used for turning wood waste into pyrolized wood char powders.The graphene content in the samples was calculated through an analysis of full width at half maximum (FWHM) of the carbon (100) crystal plane at around 42°-43° in XRD.Results showed that the FWHM and the calculated graphene sheet content of pyrolized wood char powders depended on the heat-treatment temperature,and the FWHM of wood char powder with well-developed graphene sheets (100％) was determined to be 5.0.In addition,the trend to 100％ graphene sheet-contained pyrolized carbon powder was obtained at a heattreatment temperature of 2700 ℃.The resistivity of the wood char powder with 100％ graphene sheets was predicted to be 0.01 Ω cm,close to our experimental data of 0.012 and 0.006 Ω cm for commercial graphite and graphene products,respectively.

Flammability studies of impregnated paper sheets

Science.gov (United States)

Ivan Simkovic; Anne Fuller; Robert White

2011-01-01

Paper sheets impregnated with flame retardants made from agricultural residues and other additives were studied with the cone calorimeter. The use of sugar beet ethanol eluent (SBE), CaCl2, and ZnCl2 lowered the peak rate of heat release (PRHR) the most in comparison to water treated material. The average effective heat of...

Analysis of time-dependent changes in Bitemarks on Styrofoam sheets

Directory of Open Access Journals (Sweden)

Djeapragassam Parimala

2015-01-01

Full Text Available Context: The scope of Bitemarks in forensic dentistry is widening as they help the forensic expert in identifying the perpetuator in medicolegal cases. The greatest challenge in Bitemarks analysis is the time-dependent changes produced in Bitemark patterns on various substrates at the scene of the crime. Aims: To analyze the time-dependent changes in Bitemarks on Styrofoam sheets. Settings and Design: Single centered prospective study. Materials and Methods: Twenty-five subjects were randomly chosen, and dental casts prepared. Then test bites were registered on Styrofoam sheets, overlays prepared from these test bites on subsequent days (day 1, 2, 3, 4 and checked for matching accuracy. Statistical Analysis Used: The data were analyzed using Kruskal-Wallis ANOVA to compare the overlays from dental stone cast with test bites on Styrofoam sheets on subsequent days. Results: The P value was found to be 1 which is statistically not significant implying that there were no significant time-dependent changes in the pattern of Bitemarks. Conclusions: There were no time-dependent changes in the pattern of Bitemarks on Styrofoam sheets hence they serve as better materials than Bitemarks on human skin or food substrates obtained from the scene of the crime.

Data base of radiation-resistant dielectric and insulating materials

International Nuclear Information System (INIS)

Hama, Yoshimasa; Sunazuka, Hideo; Nashiyama, Isamu; Kakuta, Tsunemi.

1987-01-01

In the data base of radiation-resistant dielectric and insulating materials, the data format contains such items as to give the summary; the data sheet contains the data in concrete form of respective properties from the references; the sheet of references contains the references in the former two. In the above three, there are attached code No., data sheet No., reference No. and key words. In the three areas as radiation-resistant dielectric and insulating materials, i.e., organic materials, inorganic materials and optical fibers, the following are explained: data format, data sheet and objectives. (Mori, K.)

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)

Beyond Slurry-Cast Supercapacitor Electrodes: PAN/MWNT Heteromat-Mediated Ultrahigh Capacitance Electrode Sheets

Science.gov (United States)

Lee, Jung Han; Kim, Jeong A.; Kim, Ju-Myung; Lee, Sun-Young; Yeon, Sun-Hwa; Lee, Sang-Young

2017-01-01

Supercapacitors (SCs) have garnered considerable attention as an appealing power source for forthcoming smart energy era. An ultimate challenge facing the SCs is the acquisition of higher energy density without impairing their other electrochemical properties. Herein, we demonstrate a new class of polyacrylonitrile (PAN)/multi-walled carbon tube (MWNT) heteromat-mediated ultrahigh capacitance electrode sheets as an unusual electrode architecture strategy to address the aforementioned issue. Vanadium pentoxide (V2O5) is chosen as a model electrode material to explore the feasibility of the suggested concept. The heteromat V2O5 electrode sheets are produced through one-pot fabrication based on concurrent electrospraying (for V2O5 precursor/MWNT) and electrospinning (for PAN nanofiber) followed by calcination, leading to compact packing of V2O5 materials in intimate contact with MWNTs and PAN nanofibers. As a consequence, the heteromat V2O5 electrode sheets offer three-dimensionally bicontinuous electron (arising from MWNT networks)/ion (from spatially reticulated interstitial voids to be filled with liquid electrolytes) conduction pathways, thereby facilitating redox reaction kinetics of V2O5 materials. In addition, elimination of heavy metallic foil current collectors, in combination with the dense packing of V2O5 materials, significantly increases (electrode sheet-based) specific capacitances far beyond those accessible with conventional slurry-cast electrodes.

The halo sign and peripancreatic fluid: useful CT signs of hypovolaemic shock complex in adults

International Nuclear Information System (INIS)

Ryan, M.F.; Hamilton, P.A.; Sarrazin, J.; Chu, P.; Benjaminov, O.; Lam, K.

2005-01-01

AIM: To report two new, useful computed tomography (CT) signs of the hypovolaemic shock complex (HSC) in adults admitted after blunt abdominal trauma: the halo sign (ring of fluid around a collapsed intra-hepatic inferior vena cava (IVC)), and peripancreatic retroperitoneal fluid. MATERIALS AND METHODS: CT images of 498 consecutive patients admitted after blunt abdominal trauma were reviewed, of which 27 had CT signs of the HSC. The CT images of these 27 patients were analysed. A control group of 101 patients examined using CT for suspected blunt abdominal trauma who did not have the HSC were chosen for comparison. RESULTS: The most common features involved the vascular compartment: diminished IVC diameter (n=27), a positive halo sign (n=21); diminished anteroposterior diameter of the aorta (n=13); and abnormal vascular enhancement (n=10). Peripancreatic retroperitoneal fluid in the absence of pancreatic injury, pancreatitis or pancreatic disease was observed in eight patients. Hollow visceral abnormalities included: diffuse increased mucosal enhancement of both the small and large bowel (n=19); diffuse thickening of the small bowel wall (n=11); and small bowel dilatation (n=7). Solid visceral abnormalities included both decreased and or increased enhancement. Several concomitant intra- and extra-abdominal injuries were also identified. CONCLUSION: In the setting of blunt abdominal trauma, early abdominal CT can show diffuse abnormalities due to the HSC, which occasionally may alert clinicians of unsuspected shock. Recognition of these signs as distinguished from injured viscera is important in order to avoid unnecessary laparotomy. Two new signs are described: the halo sign and peripancreatic retroperitoneal fluid

The halo sign and peripancreatic fluid: useful CT signs of hypovolaemic shock complex in adults

Energy Technology Data Exchange (ETDEWEB)

Ryan, M.F.; Hamilton, P.A.; Sarrazin, J.; Chu, P.; Benjaminov, O.; Lam, K

2005-05-01

AIM: To report two new, useful computed tomography (CT) signs of the hypovolaemic shock complex (HSC) in adults admitted after blunt abdominal trauma: the halo sign (ring of fluid around a collapsed intra-hepatic inferior vena cava (IVC)), and peripancreatic retroperitoneal fluid. MATERIALS AND METHODS: CT images of 498 consecutive patients admitted after blunt abdominal trauma were reviewed, of which 27 had CT signs of the HSC. The CT images of these 27 patients were analysed. A control group of 101 patients examined using CT for suspected blunt abdominal trauma who did not have the HSC were chosen for comparison. RESULTS: The most common features involved the vascular compartment: diminished IVC diameter (n=27), a positive halo sign (n=21); diminished anteroposterior diameter of the aorta (n=13); and abnormal vascular enhancement (n=10). Peripancreatic retroperitoneal fluid in the absence of pancreatic injury, pancreatitis or pancreatic disease was observed in eight patients. Hollow visceral abnormalities included: diffuse increased mucosal enhancement of both the small and large bowel (n=19); diffuse thickening of the small bowel wall (n=11); and small bowel dilatation (n=7). Solid visceral abnormalities included both decreased and or increased enhancement. Several concomitant intra- and extra-abdominal injuries were also identified. CONCLUSION: In the setting of blunt abdominal trauma, early abdominal CT can show diffuse abnormalities due to the HSC, which occasionally may alert clinicians of unsuspected shock. Recognition of these signs as distinguished from injured viscera is important in order to avoid unnecessary laparotomy. Two new signs are described: the halo sign and peripancreatic retroperitoneal fluid.

World War II Informational Fact Sheets.

Science.gov (United States)

Department of Defense, Washington, DC.

This commemorative book provides numerous fact sheets on various aspects of World War II, both on the fighting front and the homefront. Replicas of posters of the war era, descriptions of battles with maps, contributions of women and minorities to the war effort, even music of the wartime era, add to this collection of resource materials useful to…

A Collaborative Design Curriculum for Reviving Sheet Metal Handicraft

Science.gov (United States)

Chan, Patrick K. C.

2015-01-01

Galvanised sheet metal was a popular and important material for producing handmade home utensils in Hong Kong from the 1930s onwards. It was gradually replaced by new materials like stainless steel and plastic because similar goods made with these are cheaper, more standardised, more durable and of much better quality. The handicrafts behind sheet…

Numerical and experimental analysis of resistance projection welding of square nuts to sheets

DEFF Research Database (Denmark)

Nielsen, Chris Valentin; Zhang, Wenqi; Martins, Paulo A.F.

2014-01-01

Projection welding of nuts to sheets is a widely utilized manufacturing process in the automotive industry. The process entails challenges due the necessity of joining different sheet thicknesses and nut sizes made from dissimilar materials, and due to the fact of experiencing large local deforma...... of the square nut to the sheet under different operating conditions. © 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license...

History of metaphoric signs in radiology

Energy Technology Data Exchange (ETDEWEB)

Baker, Stephen R., E-mail: bakersr@umdnj.edu; Noorelahi, Yasser M., E-mail: dr.ynoorelahi@gmail.com; Ghosh, Shanchita, E-mail: Ghoshs1@umdnj.edu; Yang, Lily C., E-mail: yangclily@gmail.com; Kasper, David J., E-mail: dkasp86@gmail.com

2013-09-15

Purpose: To survey the nearly 100 year history of metaphoric sign naming in radiology describing the pace of their overall accumulation in the radiology canon, their specific rates of growth by modality and subspecialty and the characteristics of the referents to which the signs are attached. Materials and methods: A comprehensive list of metaphoric signs was compiled from a search of articles in several major English language radiology journals, from a roster compiled in a monograph on the subject published in 1984 and from a search of several databases to find signs published in the first half of the 20th century. Results: The growth of radiological metaphorical signs naming was slow for several decades after the first one was published in 1918. It then increased rapidly until the 1980s encompassing all modalities and subspecialties. Recently the practice has shown a marked and steady decline. Conclusion: Metaphoric sign naming was a frequently reported contribution to the radiological literature in the second half of the 20th century corresponding with Radiology's growth as a descriptive discipline. Its decline since then may be a consequence of Radiology's evolution into a more analytic, data-driven field of inquiry.

History of metaphoric signs in radiology

International Nuclear Information System (INIS)

Baker, Stephen R.; Noorelahi, Yasser M.; Ghosh, Shanchita; Yang, Lily C.; Kasper, David J.

2013-01-01

Purpose: To survey the nearly 100 year history of metaphoric sign naming in radiology describing the pace of their overall accumulation in the radiology canon, their specific rates of growth by modality and subspecialty and the characteristics of the referents to which the signs are attached. Materials and methods: A comprehensive list of metaphoric signs was compiled from a search of articles in several major English language radiology journals, from a roster compiled in a monograph on the subject published in 1984 and from a search of several databases to find signs published in the first half of the 20th century. Results: The growth of radiological metaphorical signs naming was slow for several decades after the first one was published in 1918. It then increased rapidly until the 1980s encompassing all modalities and subspecialties. Recently the practice has shown a marked and steady decline. Conclusion: Metaphoric sign naming was a frequently reported contribution to the radiological literature in the second half of the 20th century corresponding with Radiology's growth as a descriptive discipline. Its decline since then may be a consequence of Radiology's evolution into a more analytic, data-driven field of inquiry

Multiscale friction modeling for sheet metal forming

NARCIS (Netherlands)

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

2010-01-01

The most often used friction model for sheet metal forming simulations is the relative simple Coulomb friction model. This paper presents a more advanced friction model for large scale forming simulations based on the surface change on the micro-scale. The surface texture of a material changes when

A distributed system of wireless signs using Gyricon electronic paper displays

Science.gov (United States)

Sprague, Robert A.

2006-04-01

The proliferation of digital information is leading to a wide range of applications which make it desirable to display data easily in many locations, all changeable and updateable. The difficulty in achieving such ubiquitous displays is the cost of signage, the cost of installation, and the software and systems to control the information being sent to each of these signs. In this paper we will talk about a networked system of such signs which are made from gyricon electronic paper. Gyricon electronic paper is a reflective, bistable display which can be made in large web sheets at a reasonable price. Since it does not require a backlight nor does it require power to refresh the display image, such technology is ideal for making signs which can be run on batteries with extremely long battery life, often not needing replacement for years. The display also has a very broad illumination scattering profile which makes it readily viewable from any angle. The basic operating mechanism of the display, its manufacturing technique, and achieved performance will be described, along with the description of a networked solution using many such signs controlled with system software to identify speakers and meetings in conference rooms, hospitality suites, or classrooms in universities. Systems will also be shown which are adapted to retail pricing signage and others which can be used for large format outdoor billboards.

Forming limit and fracture mechanism of ferritic stainless steel sheets

International Nuclear Information System (INIS)

Xu Le; Barlat, Frederic; Ahn, Deok Chan; Bressan, Jose Divo

2011-01-01

Research highlights: → Forming limit curves of two ferritic stainless steel sheets were well predicted. → Failure occurs by necking in uniaxial and plane strain tension for both materials. → Failure occurs by shearing in balanced biaxial tension for both materials. → Strain rate sensitivity does not affect the limit strains a lot for both materials. → Strain rate sensitivity likely influences the failure mode for both materials. - Abstract: In this work, the forming limit curves (FLCs) of two ferritic stainless steel sheets, AISI409L and AISI430, were predicted with the Marciniak-Kuczynski (MK) and Bressan-William-Hill (BWH) models, combined with the Yld2000-2d yield function and the Swift hardening law. Uniaxial tension, disk compression and hydraulic bulge tests were performed to determine the yield loci and hardening curves of both materials. Meanwhile, the strain rate sensitivity (SRS) coefficient was measured through uniaxial tension tests carried out at different strain rates. Out-of-plane stretching tests were conducted in sheet specimens to obtain the surface limit strains under different linear strain paths. Micrographs of the specimens fractured in different stress states were obtained by optical and scanning electron microscopy. The overall results show that the BWH model can predict the FLC better than the MK model, and that the SRS does not have much effect on the limit strains for both materials. The predicted FLCs and micrograph analysis both indicate that failure occurs by surface localized necking in uniaxial and plane strain tension states, whereas it occurs by localized shearing in the through thickness direction in balanced biaxial tension state.

Theoretical analysis of sound transmission loss through graphene sheets

International Nuclear Information System (INIS)

Natsuki, Toshiaki; Ni, Qing-Qing

2014-01-01

We examine the potential of using graphene sheets (GSs) as sound insulating materials that can be used for nano-devices because of their small size, super electronic, and mechanical properties. In this study, a theoretical analysis is proposed to predict the sound transmission loss through multi-layered GSs, which are formed by stacks of GS and bound together by van der Waals (vdW) forces between individual layers. The result shows that the resonant frequencies of the sound transmission loss occur in the multi-layered GSs and the values are very high. Based on the present analytical solution, we predict the acoustic insulation property for various layers of sheets under both normal incident wave and acoustic field of random incidence source. The scheme could be useful in vibration absorption application of nano devices and materials

Theoretical analysis of sound transmission loss through graphene sheets

Energy Technology Data Exchange (ETDEWEB)

Natsuki, Toshiaki, E-mail: natsuki@shinshu-u.ac.jp [Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda 386-8567 (Japan); Institute of Carbon Science and Technology, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan); Ni, Qing-Qing [Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda 386-8567 (Japan)

2014-11-17

We examine the potential of using graphene sheets (GSs) as sound insulating materials that can be used for nano-devices because of their small size, super electronic, and mechanical properties. In this study, a theoretical analysis is proposed to predict the sound transmission loss through multi-layered GSs, which are formed by stacks of GS and bound together by van der Waals (vdW) forces between individual layers. The result shows that the resonant frequencies of the sound transmission loss occur in the multi-layered GSs and the values are very high. Based on the present analytical solution, we predict the acoustic insulation property for various layers of sheets under both normal incident wave and acoustic field of random incidence source. The scheme could be useful in vibration absorption application of nano devices and materials.

Supplementary Material

Indian Academy of Sciences (India)

mraga

1. Supplementary Material. A soluble-lead Redox Flow Battery with corrugated graphite sheet and reticulated vitreous carbon as positive and negative current collectors by A Banerjee et al (pp 163-. 170). Figure S1. SEM images for bare substrates: (a) graphite sheet, (b) 20 ppi RVC, (c) 30 ppi. RVC and (d) 45 ppi RVC.

Communication failures in patient sign-out and suggestions for improvement: a critical incident analysis.

Science.gov (United States)

Arora, V; Johnson, J; Lovinger, D; Humphrey, H J; Meltzer, D O

2005-12-01

The transfer of care for hospitalized patients between inpatient physicians is routinely mediated through written and verbal communication or "sign-out". This study aims to describe how communication failures during this process can lead to patient harm. In interviews employing critical incident technique, first year resident physicians (interns) described (1) any adverse events or near misses due to suboptimal preceding patient sign-out; (2) the worst event due to suboptimal sign-out in which they were involved; and (3) suggestions to improve sign-out. All data were analyzed and categorized using the constant comparative method with independent review by three researchers. Twenty six interns caring for 82 patients were interviewed after receiving sign-out from another intern. Twenty five discrete incidents, all the result of communication failures during the preceding patient sign-out, and 21 worst events were described. Inter-rater agreement for categorization was high (kappa 0.78-1.00). Omitted content (such as medications, active problems, pending tests) or failure-prone communication processes (such as lack of face-to-face discussion) emerged as major categories of failed communication. In nearly all cases these failures led to uncertainty during decisions on patient care. Uncertainty may result in inefficient or suboptimal care such as repeat or unnecessary tests. Interns desired thorough but relevant face-to-face verbal sign-outs that reviewed anticipated issues. They preferred legible, accurate, updated, written sign-out sheets that included standard patient content such as code status or active and anticipated medical problems. Communication failures during sign-out often lead to uncertainty in decisions on patient care. These may result in inefficient or suboptimal care leading to patient harm.

Careers "Fact Sheets" for clinical engineering & biomedical technology.

Science.gov (United States)

Pacela, A F

1991-01-01

Three Careers "Fact Sheets" include information on CE and BMET job titles, job descriptions, and certification. These materials are intended to aid in furthering professional recognition for Clinical Engineers and BMETs, and may be useful in communicating with Administration or Human Resources departments.

Molecular characterization of dissolved organic matter associated with the Greenland ice sheet

Science.gov (United States)

Bhatia, Maya P.; Das, Sarah B.; Longnecker, Krista; Charette, Matthew A.; Kujawinski, Elizabeth B.

2010-07-01

Subsurface microbial oxidation of overridden soils and vegetation beneath glaciers and ice sheets may affect global carbon budgets on glacial-interglacial timescales. The likelihood and magnitude of this process depends on the chemical nature and reactivity of the subglacial organic carbon stores. We examined the composition of carbon pools associated with different regions of the Greenland ice sheet (subglacial, supraglacial, proglacial) in order to elucidate the type of dissolved organic matter (DOM) present in the subglacial discharge over a melt season. Electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry coupled to multivariate statistics permitted unprecedented molecular level characterization of this material and revealed that carbon pools associated with discrete glacial regions are comprised of different compound classes. Specifically, a larger proportion of protein-like compounds were observed in the supraglacial samples and in the early melt season (spring) subglacial discharge. In contrast, the late melt season (summer) subglacial discharge contained a greater fraction of lignin-like and other material presumably derived from underlying vegetation and soil. These results suggest (1) that the majority of supraglacial DOM originates from autochthonous microbial processes on the ice sheet surface, (2) that the subglacial DOM contains allochthonous carbon derived from overridden soils and vegetation as well as autochthonous carbon derived from in situ microbial metabolism, and (3) that the relative contribution of allochthonous and autochthonous material in subglacial discharge varies during the melt season. These conclusions are consistent with the hypothesis that, given sufficient time (e.g., overwinter storage), resident subglacial microbial communities may oxidize terrestrial material beneath the Greenland ice sheet.

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.

Moldable cork ablation material

Science.gov (United States)

1977-01-01

A successful thermal ablative material was manufactured. Moldable cork sheets were tested for density, tensile strength, tensile elongation, thermal conductivity, compression set, and specific heat. A moldable cork sheet, therefore, was established as a realistic product.

SiC/C composite sheets produced from polycarbosilane/resin/bonder mixtures. Polycarbosilane/jushi/bonder kongokei kara sakuseishita SiC/C fukugo sheet

Energy Technology Data Exchange (ETDEWEB)

Kawamura, K. (The National Defense Academy, Kanagawa (Japan)); Koga, J.; Iwata, T.; Yamanaka, S.; Ono, M. (Mitsubishi Materials Corp., Saitama (Japan))

1992-02-01

In a course of work to improve anti-oxidative property and strength of sheets of carbonic composite materials with resins, and further to produce those sheets in an industrial scale, it was tried to prepare two types of 0.4 {approximately} 0.6 m thickness SiC / C composite sheets by heat treatment of two green sheets polycarbosilane ( PCS ) / fran resin / binder type and PCS / (phenol-formaldehyde resin / binder type ) at temperature of 1200 {approximately} 1400{degree}C in an atmosphere of nitrogen. The sheets thus made were subjected to SEM observation, X-ray diffraction, measurement of density and electric resistance, and to tests on weight loss by heating and on bending. The texture of them were as tight as that of their resin carbon ( glassy carbon ). The structural feature is formation of amorphous SiO{sub 2} as a secondary product, This indicates that Si in PCS reacts with oxygen in resin during pyrolysis. The bending strength and anti-oxidative property depend on the SiC content from PCS and that the mixing effect of SiC on them are feasible when a mixing ratio of PCS / resin is higher than (2/1). 13 ref., 7 figs., 2 tabs.

Rolling induced size effects in elastic–viscoplastic sheet metals

DEFF Research Database (Denmark)

Nielsen, Kim Lau

2015-01-01

sheet rolling, where a non-homogeneous material deformation takes place between the rollers. Large strain gradients develop where the rollers first come in contact with the sheet, and a higher order plasticity model is employed to illustrate their influence at small scales. The study reveals...... presented revolves around the rolling induced effect of visco-plasticity (ranging hot and cold rolling) in combination with strain gradient hardening – including both dissipative and energetic contributions. To bring out first order effects on rolling at small scale, the modeling efforts are limited to flat...

New developments in tribomechanical modeling of automotive sheet steel forming

Science.gov (United States)

Khandeparkar, Tushar; Chezan, Toni; van Beeck, Jeroen

2018-05-01

Forming of automotive sheet metal body panels is a complex process influenced by both the material properties and contact conditions in the forming tooling. Material properties are described by the material constitutive behavior and the material flow into the forming die can be described by the tribological system. This paper investigates the prediction accuracy of the forming process using the Tata Steel state of the art description of the material constitutive behavior in combination with different friction models. A cross-die experiment is used to investigate the accuracy of local deformation modes typically seen in automotive sheet metal forming operations. Results of advanced friction models as well as the classical Coulomb friction description are compared to the experimentally measured strain distribution and material draw-in. Two hot-dip galvanized coated steel forming grades were used for the investigations. The results show that the accuracy of the simulation is not guaranteed by the advanced friction models for the entire investigated blank holder force range, both globally and locally. A measurable difference between the calculated and measured local strains is seen for both studied models even in the case where the global indicator, i.e. the draw-in, is well predicted.

Sign Lowering and Phonetic Reduction in American Sign Language.

Science.gov (United States)

Tyrone, Martha E; Mauk, Claude E

2010-04-01

This study examines sign lowering as a form of phonetic reduction in American Sign Language. Phonetic reduction occurs in the course of normal language production, when instead of producing a carefully articulated form of a word, the language user produces a less clearly articulated form. When signs are produced in context by native signers, they often differ from the citation forms of signs. In some cases, phonetic reduction is manifested as a sign being produced at a lower location than in the citation form. Sign lowering has been documented previously, but this is the first study to examine it in phonetic detail. The data presented here are tokens of the sign WONDER, as produced by six native signers, in two phonetic contexts and at three signing rates, which were captured by optoelectronic motion capture. The results indicate that sign lowering occurred for all signers, according to the factors we manipulated. Sign production was affected by several phonetic factors that also influence speech production, namely, production rate, phonetic context, and position within an utterance. In addition, we have discovered interesting variations in sign production, which could underlie distinctions in signing style, analogous to accent or voice quality in speech.

Modified Unzipping Technique to Prepare Graphene Nano-Sheets

Science.gov (United States)

Al-Tamimi, B. H.; Farid, S. B. H.; Chyad, F. A.

2018-05-01

Graphene nano-sheets have been prepared via unzipping approach of multiwall carbon nanotubes (MWCNTs). The method includes two chemical-steps, in which a multi-parameter oxidation step is performed to achieve unzipping the carbon nanotubes. Then, a reduction step is carried out to achieve the final graphene nano-sheets. In the oxidation step, the oxidant material was minimized and balanced with longer curing time. This modification is made in order to reduce the oxygen-functional groups at the ends of graphene basal planes, which reduce its electrical conductivity. In addition, a similar adjustment is achieved in the reduction step, i.e. the consumed chemicals is reduced which make the overall process more economic and eco-friendly. The prepared nano-sheets were characterized by atomic force microscopy, scanning electron microscopy, and Raman spectroscopy. The average thickness of the prepared graphene was about 5.23 nm.

Soft material-based microculture system having air permeable cover sheet for the protoplast culture of Nicotiana tabacum.

Science.gov (United States)

Ju, Jong Il; Ko, Jung-Moon; Kim, So Hyeon; Baek, Ju Yeoul; Cha, Hyeon-Cheol; Lee, Sang Hoon

2006-08-01

In plant cell culture, the delivery of nutrition and gas (mainly oxygen) to the cells is the most important factor for viability. In this paper, we propose a polydimethylsiloxane (PDMS)-based microculture system that is designed to have good aeration. PDMS is known to have excellent air permeability, and through the experimental method, we investigated the relation between the degree of air delivery and the thickness of the PDMS sheet covering the culture chamber. We determined the proper thickness of the cover sheet, and cultured protoplasts of Nicotiana tabacum in a culture chamber covered with a PDMS sheet having thickness of 400 microm. The cells were successfully divided, and lived well inside the culture chamber for 10 days. In addition, protoplasts were cultured inside the culture chambers covered with the cover glass and the PDMS sheet, respectively, and the microcolonies were formed well inside the PDMS covered chamber after 10 days.

Study on Positive and Negative Signs in Chronic Schizophrenic Women

Directory of Open Access Journals (Sweden)

Sahel Hemmati

2002-10-01

Full Text Available Objective: Schizophrenia has different clinical manifestations, although, it is one disorder patients divided to two groups type 1 and type 2. type 1 who have positive and type 2 who have negative signs. Materials & Methods: They have chronic schizophrenia and treated at least with one antipsychotic drug. With checklist the signs were controlled. Results: In these chronic patients, hallucinations (positive sign are seen with almost all of negative signs. In the other hand, (1 Flat affect (2 A logia & volition (3 Social inattentiveness (4 Inability to feel intimacy are seen more than another signs. Conclusion: For these above  patients new antipsychotic must be examined.

Precisely Assembled Nanofiber Arrays as a Platform to Engineer Aligned Cell Sheets for Biofabrication

Directory of Open Access Journals (Sweden)

Vince Beachley

2014-08-01

Full Text Available A hybrid cell sheet engineering approach was developed using ultra-thin nanofiber arrays to host the formation of composite nanofiber/cell sheets. It was found that confluent aligned cell sheets could grow on uniaxially-aligned and crisscrossed nanofiber arrays with extremely low fiber densities. The porosity of the nanofiber sheets was sufficient to allow aligned linear myotube formation from differentiated myoblasts on both sides of the nanofiber sheets, in spite of single-side cell seeding. The nanofiber content of the composite cell sheets is minimized to reduce the hindrance to cell migration, cell-cell contacts, mass transport, as well as the foreign body response or inflammatory response associated with the biomaterial. Even at extremely low densities, the nanofiber component significantly enhanced the stability and mechanical properties of the composite cell sheets. In addition, the aligned nanofiber arrays imparted excellent handling properties to the composite cell sheets, which allowed easy processing into more complex, thick 3D structures of higher hierarchy. Aligned nanofiber array-based composite cell sheet engineering combines several advantages of material-free cell sheet engineering and polymer scaffold-based cell sheet engineering; and it represents a new direction in aligned cell sheet engineering for a multitude of tissue engineering applications.

Design of Helical Self-Piercing Rivet for Joining Aluminum Alloy and High-Strength Steel Sheets

International Nuclear Information System (INIS)

Kim, W. Y.; Kim, D. B.; Park, J. G; Kim, D. H.; Kim, K. H.; Lee, I. H.; Cho, H. Y.

2014-01-01

A self-piercing rivet (SPR) is a mechanical component for joining dissimilar material sheets such as those of aluminum alloy and steel. Unlike conventional rivets, the SPR directly pierces sheets without the need for drilling them beforehand. However, the regular SPR can undergo buckling when it pierces a high-strength steel sheet, warranting the design of a helical SPR. In this study, the joining and forging processes using the helical SPR were simulated using the commercial FEM code, DEFORM-3D. High-tensile-strength steel sheets of different strengths were joined with aluminum alloy sheets using the designed helical SPR. The simulation results were found to agree with the experimental results, validating the optimal design of a helical SPR that can pierce high-strength steel sheets

Design of Helical Self-Piercing Rivet for Joining Aluminum Alloy and High-Strength Steel Sheets

Energy Technology Data Exchange (ETDEWEB)

Kim, W. Y.; Kim, D. B.; Park, J. G; Kim, D. H.; Kim, K. H.; Lee, I. H.; Cho, H. Y. [Chungbuk National University, Cheongju (Korea, Republic of)

2014-07-15

A self-piercing rivet (SPR) is a mechanical component for joining dissimilar material sheets such as those of aluminum alloy and steel. Unlike conventional rivets, the SPR directly pierces sheets without the need for drilling them beforehand. However, the regular SPR can undergo buckling when it pierces a high-strength steel sheet, warranting the design of a helical SPR. In this study, the joining and forging processes using the helical SPR were simulated using the commercial FEM code, DEFORM-3D. High-tensile-strength steel sheets of different strengths were joined with aluminum alloy sheets using the designed helical SPR. The simulation results were found to agree with the experimental results, validating the optimal design of a helical SPR that can pierce high-strength steel sheets.

Radiation application for paper preservation: gamma irradiation at Eucalyptus pulp sheets

International Nuclear Information System (INIS)

Borrely, Sueli Ivone; Barbosa, Patricia S.M.; D'Almeida, Maria Luiza O.

2009-01-01

Ionizing radiation has been proposed in order to protect information and books that may be lost due to fungi and or insects infestation. In general restaurators are very worried about the maintenance of original properties of items to be treated. The selected technology must consider two points: type of biological contamination and contamination control. Fungi is one of the principal organism which grows well on papers. Once this infestation is installed on the paper it will signify spots, resistance loses and deterioration. The organisms feces introduces enzymes, organic acids and pigments to the contaminated material. Ionizing radiation from gamma sources were applied at laboratory sheets manufactured with commercial cellulose pulp. The subject of this present paper was to investigate the ideal radiation dose that is safe for keeping the paper quality. Laboratory sheets (75 g/m 2 ) were prepared in a TAPPI sheet former. Bleached sulphate Eucalyptus pulp, refined in laboratory PFI mill to 31 deg SR, was the raw material. The formed sheets were irradiated at IPEN's 60 Co Gammacell with 3 kGy up to 25 kGy. No significant changes were detected in paper samples irradiated up to 9 kGy. This is the radiation dose to be suggested. During irradiation the applied dose rate was 0.817 Gy/s. (author)

Plastic Deformation Characteristics Of AZ31 Magnesium Alloy Sheets At Elevated Temperature

International Nuclear Information System (INIS)

Park, Jingee; Lee, Jongshin; You, Bongsun; Choi, Seogou; Kim, Youngsuk

2007-01-01

Using lightweight materials is the emerging need in order to reduce the vehicle's energy consumption and pollutant emissions. Being a lightweight material, magnesium alloys are increasingly employed in the fabrication of automotive and electronic parts. Presently, magnesium alloys used in automotive and electronic parts are mainly processed by die casting. The die casting technology allows the manufacturing of parts with complex geometry. However, the mechanical properties of these parts often do not meet the requirements concerning the mechanical properties (e.g. endurance strength and ductility). A promising alternative can be forming process. The parts manufactured by forming could have fine-grained structure without porosity and improved mechanical properties such as endurance strength and ductility. Because magnesium alloy has low formability resulted form its small slip system at room temperature it is usually formed at elevated temperature. Due to a rapid increase of usage of magnesium sheets in automotive and electronic industry it is necessary to assure database for sheet metal formability and plastic yielding properties in order to optimize its usage. Especially, plastic yielding criterion is a critical property to predict plastic deformation of sheet metal parts in optimizing process using CAE simulation. Von-Mises yield criterion generally well predicts plastic deformation of steel sheets and Hill'1979 yield criterion predicts plastic deformation of aluminum sheets. In this study, using biaxial tensile test machine yield loci of AZ31 magnesium alloy sheet were obtained at elevated temperature. The yield loci ensured experimentally were compared with the theoretical predictions based on the Von-Mises, Hill, Logan-Hosford, and Barlat model

Development of a low energy micro sheet forming machine

Science.gov (United States)

Razali, A. R.; Ann, C. T.; Shariff, H. M.; Kasim, N. I.; Musa, M. A.; Ahmad, A. F.

2017-10-01

It is expected that with the miniaturization of materials being processed, energy consumption is also being `miniaturized' proportionally. The focus of this study was to design a low energy micro-sheet-forming machine for thin sheet metal application and fabricate a low direct current powered micro-sheet-forming machine. A prototype of low energy system for a micro-sheet-forming machine which includes mechanical and electronic elements was developed. The machine was tested for its performance in terms of natural frequency, punching forces, punching speed and capability, energy consumption (single punch and frequency-time based). Based on the experiments, the machine can do 600 stroke per minute and the process is unaffected by the machine's natural frequency. It was also found that sub-Joule of power was required for a single stroke of punching/blanking process. Up to 100micron thick carbon steel shim was successfully tested and punched. It concludes that low power forming machine is feasible to be developed and be used to replace high powered machineries to form micro-products/parts.

Transition from Sign-Reversed to Sign-Preserved Cooper-Pairing Symmetry in Sulfur-Doped Iron Selenide Superconductors.

Science.gov (United States)

Wang, Qisi; Park, J T; Feng, Yu; Shen, Yao; Hao, Yiqing; Pan, Bingying; Lynn, J W; Ivanov, A; Chi, Songxue; Matsuda, M; Cao, Huibo; Birgeneau, R J; Efremov, D V; Zhao, Jun

2016-05-13

An essential step toward elucidating the mechanism of superconductivity is to determine the sign or phase of the superconducting order parameter, as it is closely related to the pairing interaction. In conventional superconductors, the electron-phonon interaction induces attraction between electrons near the Fermi energy and results in a sign-preserved s-wave pairing. For high-temperature superconductors, including cuprates and iron-based superconductors, prevalent weak coupling theories suggest that the electron pairing is mediated by spin fluctuations which lead to repulsive interactions, and therefore that a sign-reversed pairing with an s_{±} or d-wave symmetry is favored. Here, by using magnetic neutron scattering, a phase sensitive probe of the superconducting gap, we report the observation of a transition from the sign-reversed to sign-preserved Cooper-pairing symmetry with insignificant changes in T_{c} in the S-doped iron selenide superconductors K_{x}Fe_{2-y}(Se_{1-z}S_{z})_{2}. We show that a rather sharp magnetic resonant mode well below the superconducting gap (2Δ) in the undoped sample (z=0) is replaced by a broad hump structure above 2Δ under 50% S doping. These results cannot be readily explained by simple spin fluctuation-exchange pairing theories and, therefore, multiple pairing channels are required to describe superconductivity in this system. Our findings may also yield a simple explanation for the sometimes contradictory data on the sign of the superconducting order parameter in iron-based materials.

Increased Tensile Strength of Carbon Nanotube Yarns and Sheets through Chemical Modification and Electron Beam Irradiation

Science.gov (United States)

Miller, Sandi G.; Williams, Tiffany S.; Baker, James S.; Sola, Francisco; Lebron-Colon, Marisabel; McCorkle, Linda S.; Wilmoth, Nathan G.; Gaier, James; Chen, Michelle; Meador, Michael A.

2014-01-01

The inherent strength of individual carbon nanotubes offers considerable opportunity for the development of advanced, lightweight composite structures. Recent work in the fabrication and application of carbon nanotube (CNT) forms such as yarns and sheets has addressed early nanocomposite limitations with respect to nanotube dispersion and loading; and has pushed the technology toward structural composite applications. However, the high tensile strength of an individual CNT has not directly translated to macro-scale CNT forms where bulk material strength is limited by inter-tube electrostatic attraction and slippage. The focus of this work was to assess post processing of CNT sheet and yarn to improve the macro-scale strength of these material forms. Both small molecule functionalization and e-beam irradiation was evaluated as a means to enhance tensile strength and Youngs modulus of the bulk CNT material. Mechanical testing results revealed a tensile strength increase in CNT sheets by 57 when functionalized, while an additional 48 increase in tensile strength was observed when functionalized sheets were irradiated; compared to unfunctionalized sheets. Similarly, small molecule functionalization increased yarn tensile strength up to 25, whereas irradiation of the functionalized yarns pushed the tensile strength to 88 beyond that of the baseline yarn.

The Forming of AISI 409 sheets for fan blade manufacturing

International Nuclear Information System (INIS)

Foroni, F. D.; Menezes, M. A.; Moreira Filho, L. A.

2007-01-01

The necessity of adapting the standardized fan models to conditions of higher temperature has emerged due to the growth of concern referring to the consequences of the gas expelling after the Mont Blanc tunnel accident in Italy and France, where even though, with 100 fans in operation, 41 people died. The objective of this work is to present an alternative to the market standard fans considering a new technology in constructing blades. This new technology introduces the use of the stainless steel AISI 409 due to its good to temperatures of gas exhaust from tunnels in fire situation. The innovation is centered in the process of a deep drawing of metallic sheets in order to keep the ideal aerodynamic superficies for the fan ideal performance. Through the impression of circles on the sheet plane it is shown, experimentally, that, during the pressing process, the more deformed regions on the sheet plane of the blade can not reach the deformation limits of the utilized sheet material

Testing and modelling of industrial tribo-systems for sheet metal forming

DEFF Research Database (Denmark)

Friis, Kasper Leth; Nielsen, Peter Søe; Bay, Niels

2008-01-01

Galling is a well-known problem in sheet metal forming of tribological difficult materials such as stainless steel. In this work new, environmentally friendly lubricants and wear resistant tool materials are tested in a laboratory environment using a strip reduction test as well as in a real...

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.

Constitutive modeling for analysis and design of aluminum sheet forming processes

International Nuclear Information System (INIS)

Barlat, F.; Chung, K.; Yoon, J-W.; Choi, S-H.

2000-01-01

Finite element modeling (FEM) technology is one of the most powerful tools used to design new products, i.e. appliances, automotive, rigid packaging and aerospace parts, etc., and processes. However, FEM users need data and models to characterize the materials used to fabricate the new products. In fact, they need more information than the traditional and standard yield strength, ultimate strength, elongation, etc. Constitutive models and their associated coefficients represent a new way to describe material properties, a way that can be used by FEM users. In order to help manufacturers use more aluminum alloy sheet in their products, appropriate material models are needed to analyze and design specifically for these materials. This work describes a methodology that provides phenomenological constitutive equations based on three main microstructure components of aluminum alloys: dislocation density, second-phase particles and crystallographic texture. Examples of constitutive equations and their applications to numerical sheet forming process analysis and design are provided in this work. (author)

A Modified Porous Titanium Sheet Prepared by Plasma-Activated Sintering for Biomedical Applications

Directory of Open Access Journals (Sweden)

Yukimichi Tamaki

2010-01-01

Full Text Available This study aimed to develop a contamination-free porous titanium scaffold by a plasma-activated sintering within an originally developed TiN-coated graphite mold. The surface of porous titanium sheet with or without a coated graphite mold was characterized. The cell adhesion property of porous titanium sheet was also evaluated in this study. The peak of TiC was detected on the titanium sheet processed with the graphite mold without a TiN coating. Since the titanium fiber elements were directly in contact with the carbon graphite mold during processing, surface contamination was unavoidable event in this condition. The TiC peak was not detectable on the titanium sheet processed within the TiN-coated carbon graphite mold. This modified plasma-activated sintering with the TiN-coated graphite mold would be useful to fabricate a contamination-free titanium sheet. The number of adherent cells on the modified titanium sheet was greater than that of the bare titanium plate. Stress fiber formation and the extension of the cells were observed on the titanium sheets. This modified titanium sheet is expected to be a new tissue engineering material in orthopedic bone repair.

Nuclear Material Information Quality Control for Safeguards Purposes in South Africa

International Nuclear Information System (INIS)

Nel, H.; Rasweswe, M.; Bopape, A.

2015-01-01

The State System of Accounting and Control of Nuclear Material (SSAC) in South Africa comprises a State Inspectorate, Technical Support and Safeguards Information Systems (SIS). SIS is responsible for the quality control and assurance of the Nuclear Material Reports, Additional Protocol declarations and submission to the IAEA. Monthly reports are received from the facilities where inventory changes took place. Reports are prepared according to a Quality Management Document: Instruction for the Completion of Nuclear Material Accounting Reports. The inventory changes are reported on spreadsheets developed for our system. The Inventory Change Reports (ICR) and General Ledgers (GL) are compared line by line to check for discrepancies, which will be noted on a Control Sheet. The form will be sent to the relevant facility to notify them of corrections needed. The corrected reports will be re-submitted to SIS. A spreadsheet is used in the verification process with columns for all material categories and inventory change codes. The ICR totals of all inventory changes can be reconciled with the GL values. If all the entries are correct the nuclear material totals should be the same as on the GL. The facility file is checked by the State Inspector responsible for the specific facility as a second round of quality control. The inspector is required to sign the Control Sheet to confirm the completeness and correctness of the reports. The Excel data is then converted into a text (.txt) file, encrypted and then submitted electronically to the Agency. This paper will present all the steps involved in ensuring the correctness of the reports and the quality control measures in detail used by the South Africa SSAC. (author)

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.

SPR Characteristics Curve and Distribution of Residual Stress in Self-Piercing Riveted Joints of Steel Sheets

Directory of Open Access Journals (Sweden)

Rezwanul Haque

2017-01-01

Full Text Available Neutron diffraction was used to describe the residual stress distributions in self-piercing riveted (SPR joints. The sheet material displayed a compressive residual stress near the joint, and the stress gradually became tensile in the sheet material far away from the joint. The stress in the rivet leg was lower in the thick joint of the softer steel sheet than in the thin joint of the harder steel sheet. This lower magnitude was attributed to the lower force gradient during the rivet flaring stage of the SPR process curve. This study shows how the residual stress results may be related to the physical occurrences that happened during joining, using the characteristics curve. The study also shows that neutron diffraction technique enabled a crack in the rivet tip to be detected which was not apparent from a cross-section.

Singular Sheet Etching of Graphene with Oxygen Plasma

Institute of Scientific and Technical Information of China (English)

Haider Al-Mumen; Fubo Rao; Wen Li; Lixin Dong

2014-01-01

This paper reports a simple and controllable post-synthesis method for engineering the number of graphene layers based on oxygen plasma etching. Singular sheet etching(SSE) of graphene was achieved with the optimum process duration of 38 seconds. As a demonstration of this SSE process, monolayer graphene films were produced from bilayer graphenes. Experimental investigations verified that the oxygen plasma etching removes a single layer graphene sheet in an anisotropic fashion rather than anisotropic mode. In addition,etching via the oxygen plasma at the ground electrodes introduced fewer defects to the bottom graphene layer compared with the conventional oxygen reactive ion etching using the powered electrodes. Such defects can further be reduced with an effective annealing treatment in an argon environment at 900-1000?C. These results demonstrate that our developed SSE method has enabled a microelectronics manufacturing compatible way for single sheet precision subtraction of graphene layers and a potential technique for producing large size graphenes with high yield from multilayer graphite materials.

Singular Sheet Etching of Graphene with Oxygen Plasma

Institute of Scientific and Technical Information of China (English)

Haider Al-Mumen; Fubo Rao; Wen Li; Lixin Dong

2014-01-01

This paper reports a simple and controllable post-synthesis method for engineering the number of graphene layers based on oxygen plasma etching. Singular sheet etching (SSE) of graphene was achieved with the optimum process duration of 38 seconds. As a demonstration of this SSE process, monolayer graphene films were produced from bilayer graphenes. Experimental investigations verified that the oxygen plasma etching removes a single layer graphene sheet in an anisotropic fashion rather than anisotropic mode. In addition, etching via the oxygen plasma at the ground electrodes introduced fewer defects to the bottom graphene layer compared with the conventional oxygen reactive ion etching using the powered electrodes. Such defects can further be reduced with an effective annealing treatment in an argon environment at 900-1000◦C. These results demonstrate that our developed SSE method has enabled a microelectronics manufacturing compatible way for single sheet precision subtraction of graphene layers and a potential technique for producing large size graphenes with high yield from multilayer graphite materials.

75 FR 53841 - Display of Official Sign; Permanent Increase in Standard Maximum Share Insurance Amount

Science.gov (United States)

2010-09-02

... to replace the old version of the official sign with the revised official sign at required locations.... Additionally, a credit union must replace the old version of the official sign with the revised official sign... internet signs and deplete its stockpiles of other printed advertising materials. NCUA also believes that...

Arrangement for underground storage of materials of every kind

International Nuclear Information System (INIS)

Marek, O.; Seisenbacher, H.; Toth, L.

1982-01-01

Construction of a spheroidal tank, made of two sheets of concrete, used for underground storage. Space between inner and outer sheet is filled with a vibration absorbing material. The bottom of the outer sheet is made of material with lower rigidness, which allows the line of fault in cases of tectonic motions to slide off. (J.K.) [de

Application of Multivariate Adaptive Regression Splines to Sheet Metal Bending Process for Springback Compensation

Directory of Open Access Journals (Sweden)

Dilan Rasim Aşkın

2016-01-01

Full Text Available An intelligent regression technique is applied for sheet metal bending processes to improve bending performance. This study is a part of another extensive study, automated sheet bending assistance for press brakes. Data related to material properties of sheet metal is collected in an online manner and fed to an intelligent system for determining the most accurate punch displacement without any offline iteration or calibration. The overall system aims to reduce the production time while increasing the performance of press brakes.

Influence of heat treatment on the microstructure, texture and formability of 2024 aluminium alloy

Energy Technology Data Exchange (ETDEWEB)

Moy, Charles K.S., E-mail: cloo8000@uni.sydney.edu.au [Australian Centre for Microscopy and Microanalysis, University of Sydney, NSW 2006 (Australia); ARC Centre of Excellence for Design in Light Metals, University of Sydney, NSW 2006 (Australia); School of Civil Engineering, University of Sydney, NSW 2006 (Australia); Weiss, Matthias [Centre for Materials and Fibre Innovation, Deakin University, VIC 3217 (Australia); Xia, Junhai [Australian Centre for Microscopy and Microanalysis, University of Sydney, NSW 2006 (Australia); Sha, Gang; Ringer, Simon P. [Australian Centre for Microscopy and Microanalysis, University of Sydney, NSW 2006 (Australia); ARC Centre of Excellence for Design in Light Metals, University of Sydney, NSW 2006 (Australia); Ranzi, Gianluca [Australian Centre for Microscopy and Microanalysis, University of Sydney, NSW 2006 (Australia); ARC Centre of Excellence for Design in Light Metals, University of Sydney, NSW 2006 (Australia); School of Civil Engineering, University of Sydney, NSW 2006 (Australia)

2012-08-30

We have investigated the effect of heat treatment on the microstructure, texture and formability of high-strength aluminium Al2024 sheets of gauge thicknesses 1.27 mm and 2.03 mm. Both optical and electron microscopy were employed to characterise the microstructure. Tensile tests performed at 0 Degree-Sign , 45 Degree-Sign and 90 Degree-Sign to the rolling direction were used as an indication of the anisotropic behaviour of the sheets. The formability of the sheets was assessed by performing stretch forming tests over a hemispherical punch. Comparison of microstructure and material properties indicated an effect of precipitation hardening on the overall anisotropy of the investigated materials. We report an improvement in the total elongation under uniaxial tension with a loss in strength for 2.5 h and 2 days ageing while the ageing treatment for 1 week (peak hardness) resulted in increased strength with a decline in total elongation. The 1.27 mm thick sheet showed better drawability and least tendency to earing than the thicker sheet. The drawability was the highest at 45 Degree-Sign to the rolling direction for the as-received material and those that had been aged for 2.5 h and 2 days. Forming limit diagrams derived from the stretch forming tests showed that the 2 days aged sample had the highest plane strain limit making it the most appropriate condition considering that the plane strain is usually the most critical forming strain in stamping applications. In addition, the 2 days aged sample had its plane strain shifted towards the biaxial stretching area which is likely to have a positive effect on some sheet forming applications. Finally, a formability index was calculated and compared against the hardness plot.

Graphene: powder, flakes, ribbons, and sheets.

Science.gov (United States)

James, Dustin K; Tour, James M

2013-10-15

Graphene's unique physical and electrical properties (high tensile strength, Young's modulus, electron mobility, and thermal conductivity) have led to its nickname of "super carbon." Graphene research involves the study of several different physical forms of the material: powders, flakes, ribbons, and sheets and others not yet named or imagined. Within those forms, graphene can include a single layer, two layers, or ≤10 sheets of sp² carbon atoms. The chemistry and applications available with graphene depend on both the physical form of the graphene and the number of layers in the material. Therefore the available permutations of graphene are numerous, and we will discuss a subset of this work, covering some of our research on the synthesis and use of many of the different physical and layered forms of graphene. Initially, we worked with commercially available graphite, with which we extended diazonium chemistry developed to functionalize single-walled carbon nanotubes to produce graphitic materials. These structures were soluble in common organic solvents and were better dispersed in composites. We developed an improved synthesis of graphene oxide (GO) and explored how the workup protocol for the synthesis of GO can change the electronic structure and chemical functionality of the GO product. We also developed a method to remove graphene layers one-by-one from flakes. These powders and sheets of GO can serve as fluid loss prevention additives in drilling fluids for the oil industry. Graphene nanoribbons (GNRs) combine small width with long length, producing valuable electronic and physical properties. We developed two complementary syntheses of GNRs from multiwalled carbon nanotubes: one simple oxidative method that produces GNRs with some defects and one reductive method that produces GNRs that are less defective and more electrically conductive. These GNRs can be used in low-loss, high permittivity composites, as conductive reinforcement coatings on Kevlar

Adult Sail Sign: Radiographic and Computed Tomographic Features

Energy Technology Data Exchange (ETDEWEB)

Lee, Yu-Jin; Han, Daehee; Koh, Young Hwan; Zo, Joo Hee; Kim, Sang-Hyun; Kim, Deog Kyeom; Lee, Jeong Sang; Moon, Hyeon Jong; Kim, Jong Seung; Chun, Eun Ju; Youn, Byung Jae; Lee, Chang Hyun; Kim, Sam Soo (Dept. of Radiology, Cheil General Hospital, Kwandong Univ. College of Medicine, Seoul (KR))

2008-02-15

Background: The sail sign is a well-known radiographic feature of the pediatric chest. This sign can be observed in an adult population as well, but for a different reason. Purpose: To investigate the sail sign appearing in adult chest radiography. Material and Methods: Based on two anecdotal adult cases in which frontal chest radiographs showed the sail sign, we prospectively screened radiographs of 10,238 patients to determine the incidence of the sail sign found in adults in their 40s or older. The cause of the sail sign was assessed using computed tomography (CT). Results: The sail sign was revealed in 10 (seven males, three females; median age 60.6 years) of 10,238 patients. Of these 10 patients with a sail sign on frontal radiographs, eight underwent CT. The frontal radiographs of these 10 patients showed a concave superior margin toward the lung in nine patients, a concave inferior margin in five, and a double-lined inferior margin in three. Lateral radiographs disclosed a focal opacity over the minor fissure in five of six patients, which was either fuzzy (n = 4) or sharp (n = 1) in its upper margin, and was sometimes double lined in the inferior margin (n = 3). CT revealed the anterior mediastinal fat to be the cause of the radiographic sail sign, which stretched laterally from the mediastinum to insinuate into the minor fissure. Conclusion: The incidence of sail sign on adult chest radiographs is about 0.1%. The sign is specific enough to eliminate the need for more sophisticated imaging

Adult Sail Sign: Radiographic and Computed Tomographic Features

International Nuclear Information System (INIS)

Lee, Yu-Jin; Han, Daehee; Koh, Young Hwan; Zo, Joo Hee; Kim, Sang-Hyun; Kim, Deog Kyeom; Lee, Jeong Sang; Moon, Hyeon Jong; Kim, Jong Seung; Chun, Eun Ju; Y oun, Byung Jae; Lee, Chang Hyun; Kim, Sam Soo

2008-01-01

Background: The sail sign is a well-known radiographic feature of the pediatric chest. This sign can be observed in an adult population as well, but for a different reason. Purpose: To investigate the sail sign appearing in adult chest radiography. Material and Methods: Based on two anecdotal adult cases in which frontal chest radiographs showed the sail sign, we prospectively screened radiographs of 10,238 patients to determine the incidence of the sail sign found in adults in their 40s or older. The cause of the sail sign was assessed using computed tomography (CT). Results: The sail sign was revealed in 10 (seven males, three females; median age 60.6 years) of 10,238 patients. Of these 10 patients with a sail sign on frontal radiographs, eight underwent CT. The frontal radiographs of these 10 patients showed a concave superior margin toward the lung in nine patients, a concave inferior margin in five, and a double-lined inferior margin in three. Lateral radiographs disclosed a focal opacity over the minor fissure in five of six patients, which was either fuzzy (n = 4) or sharp (n = 1) in its upper margin, and was sometimes double lined in the inferior margin (n = 3). CT revealed the anterior mediastinal fat to be the cause of the radiographic sail sign, which stretched laterally from the mediastinum to insinuate into the minor fissure. Conclusion: The incidence of sail sign on adult chest radiographs is about 0.1%. The sign is specific enough to eliminate the need for more sophisticated imaging

Three-dimensional shape transformations of hydrogel sheets induced by small-scale modulation of internal stresses

Science.gov (United States)

Wu, Zi Liang; Moshe, Michael; Greener, Jesse; Therien-Aubin, Heloise; Nie, Zhihong; Sharon, Eran; Kumacheva, Eugenia

2013-03-01

Although Nature has always been a common source of inspiration in the development of artificial materials, only recently has the ability of man-made materials to produce complex three-dimensional (3D) structures from two-dimensional sheets been explored. Here we present a new approach to the self-shaping of soft matter that mimics fibrous plant tissues by exploiting small-scale variations in the internal stresses to form three-dimensional morphologies. We design single-layer hydrogel sheets with chemically distinct, fibre-like regions that exhibit differential shrinkage and elastic moduli under the application of external stimulus. Using a planar-to-helical three-dimensional shape transformation as an example, we explore the relation between the internal architecture of the sheets and their transition to cylindrical and conical helices with specific structural characteristics. The ability to engineer multiple three-dimensional shape transformations determined by small-scale patterns in a hydrogel sheet represents a promising step in the development of programmable soft matter.

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 ( ...

Comparison of Two Commercial FE-Codes for Sheet Metal Forming

International Nuclear Information System (INIS)

Revuelta, A.; Larkiola, J.; Kanervo, K.; Korhonen, A. S.; Myllykoski, P.

2007-01-01

There is urgent need to develop new advanced fast and cost-effective mass-production methods for small sheet metal components. Traditionally progressive dies have been designed by using various CAD techniques. Recent results in mass production of small sheet metal parts using progressive dies and a transfer press showed that the tool design time may be cut in up to a half by using 3D finite element simulation of forming. In numerical simulation of sheet metal forming better constitutive models are required to obtain more accurate results, reduce the time for tool design and cut the production costs further. Accurate models are needed to describe the initial yielding, subsequent work hardening and to predict the formability. In this work two commercially available finite element simulation codes, PAM-STAMP and LS-DYNA, were compared in forming of small austenitic stainless steel sheet part for electronic industry. Several constitutive models were used in both codes and the results were compared. Comparisons were made between the same models in each of the codes and also between different models in the same code. Material models ranged from very simple to advanced ones, which took into account anisotropy and both isotropic and kinematic hardening behavior. In order to make a valid comparison we employed similar finite element meshes. The effects of the material models parameters were studied and the results were compared with experiments. The effects of the computational time were also studied

A comparative study of electrochemical performance of graphene sheets, expanded graphite and natural graphite as anode materials for lithium-ion batteries

International Nuclear Information System (INIS)

Bai, Li-Zhong; Zhao, Dong-Lin; Zhang, Tai-Ming; Xie, Wei-Gang; Zhang, Ji-Ming; Shen, Zeng-Min

2013-01-01

Highlights: • Graphene sheets (GSs), expanded graphite (EG) and natural graphite (NG) were comparatively investigated as anode materials for lithium-ion batteries. • The reversible capacity of GS electrode was almost twice that of EG electrode and three times that of NG electrode. • The first-cycle coulombic efficiency and capacity retention of NG were much bigger than those of GSs and EG. • GS and EG electrodes exhibited higher electrochemical activity and more favorable kinetic properties. -- Abstract: Three kinds of carbon materials, i.e., graphene sheets (GSs), expanded graphite (EG) and natural graphite (NG) were comparatively investigated as anode materials for lithium-ion batteries via scanning electron microscope, high-resolution transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy and a variety of electrochemical testing techniques. The test results showed that the reversible capacities of GS electrode were 1130 and 636 mA h g −1 at the current densities of 0.2 and 1 mA cm −2 , respectively, which were almost twice those of EG electrode and three times those of NG electrode. The first-cycle coulombic efficiency and capacity retention of NG were much bigger than those of GSs and EG. The notable capacity fading observed in GSs and EG may be ascribed to the disorder-induced structure instability. The larger voltage hysteresis in GS and EG electrodes was not only related to the surface functional groups, but also to the active defects in GSs and EG, which results in greater hindrance and higher overvoltage during lithium extraction from electrode. The kinetics properties of GSs, EG and NG electrodes were compared by AC impedance measurements. GS and EG electrodes exhibited higher electrochemical activity and more favorable kinetic properties during charge and discharge process

Microstructure Reconstruction of Sheet Molding Composite Using a Random Chips Packing Algorithm

Energy Technology Data Exchange (ETDEWEB)

Huang, Tianyu; Xu, Hongyi; Chen, Wei

2017-04-06

Fiber-reinforced polymer composites are strong candidates for structural materials to replace steel and light alloys in lightweight vehicle design because of their low density and relatively high strength. In the integrated computational materials engineering (ICME) development of carbon fiber composites, microstructure reconstruction algorithms are needed to generate material microstructure representative volume element (RVE) based on the material processing information. The microstructure RVE reconstruction enables the material property prediction by finite element analysis (FEA)This paper presents an algorithm to reconstruct the microstructure of a chopped carbon fiber/epoxy laminate material system produced by compression molding, normally known as sheet molding compounds (SMC). The algorithm takes the result from material’s manufacturing process as inputs, such as the orientation tensor of fibers, the chopped fiber sheet geometry, and the fiber volume fraction. The chopped fiber sheets are treated as deformable rectangle chips and a random packing algorithm is developed to pack these chips into a square plate. The RVE is built in a layer-by-layer fashion until the desired number of lamina is reached, then a fine tuning process is applied to finalize the reconstruction. Compared to the previous methods, this new approach has the ability to model bended fibers by allowing limited amount of overlaps of rectangle chips. Furthermore, the method does not need SMC microstructure images, for which the image-based characterization techniques have not been mature enough, as inputs. Case studies are performed and the results show that the statistics of the reconstructed microstructures generated by the algorithm matches well with the target input parameters from processing.

DEVELOPING SIGNS AND SONGS MATERIALS DEALING WITH THE 2013 CURRICULUM FOR THE SEVENTH GRADE STUDENTS IN MTSN BALANG-BALANG

Directory of Open Access Journals (Sweden)

Mardiana

2016-04-01

Full Text Available This research aimed to develop Signs and Songs Materials based on 2013 curriculum for the Seventh Grade Student at MTsN. BalangBalang, Gowa. It was Research and Development (R&D applied ADDIE model standing for Analysis, Design, Develop, Implement, and Evaluate. The procedures were; 1 analyzing materials needed by students; 2designing the blueprint; 3 developing the materials through the syllabus of 2013 Curriculum; 4 implementing the product (try-out product; and 5 evaluating the product. The product was tried out to the seventh grade students at MTsN Balang-balang. Type of data obtained in this study was qualitative. The instruments used in this study were questionnaire and rubrics for teacher and expert. Then, the teacher and expert were involved in order to validate the product. They validated three systematic aspects of the product, namely; the organization of the Materials, English Teaching strategies or method, and the content of the materials. Finally, based on the teacher and expert judgment as well as try-out design result, it was found that the developed materials were applicable to be taught for the Seventh Grade of Junior High School as additional learning and teaching materials which help both students and teachers in learning process based on 2013 Curriculum.

A flexible tactile sensitive sheet using a hetero-core fiber optic sensor

Science.gov (United States)

Fujino, S.; Yamazaki, H.; Hosoki, A.; Watanabe, K.

2014-05-01

In this report, we have designed a tactile sensitive sheet based on a hetero-core fiber-optic sensor, which realize an areal sensing by using single sensor potion in one optical fiber line. Recently, flexible and wide-area tactile sensing technology is expected to applied to acquired biological information in living space and robot achieve long-term care services such as welfare and nursing-care and humanoid technology. A hetero-core fiber-optic sensor has several advantages such as thin and flexible transmission line, immunity to EMI. Additionally this sensor is sensitive to moderate bending actions with optical loss changes and is independent of temperature fluctuation. Thus, the hetero-core fiber-optic sensor can be suitable for areal tactile sensing. We measure pressure characteristic of the proposed sensitive sheet by changing the pressure position and pinching characteristic on the surface. The proposed tactile sensitive sheet shows monotonic responses on the whole sensitive sheet surface although different sensitivity by the position is observed at the sensitive sheet surface. Moreover, the tactile sensitive sheet could sufficiently detect the pinching motion. In addition, in order to realize the discrimination between pressure and pinch, we fabricated a doubled-over sensor using a set of tactile sensitive sheets, which has different kinds of silicon robbers as a sensitive sheet surface. In conclusion, the flexible material could be given to the tactile sensation which is attached under proposed sensitive sheet.

Non-contact sheet forming using lasers applied to a high strength aluminum alloy

Directory of Open Access Journals (Sweden)

Rafael Humberto Mota Siqueira

2016-07-01

Full Text Available Laser beam forming (LBF is a contactless mechanical process accomplished by the introduction of thermal stresses on the surface of a material using a laser in order to induce plastic deformation. In this work, LBF was performed on 1.6 mm thick sheets of a high strength aluminum alloy, AA6013-T4 class by using a defocused continuous Yb-fiber laser beam of 0.6 mm in diameter on the sheet top surface. The laser power and process speed were varied from 200 W to 2000 W and from 3 to 30 mm/s, respectively. For these experimental conditions, the bending angle of the sheet ranged from 0.1° to 2.5° per run. In the highest bending angle condition, 1000 W and 30 mm/s, the depth of remelted pool was 0.6 mm and the microstructure near the plate bottom surface remained unaltered. For the whole set of experimental conditions, the hardness remained constant at approximately 100 HV, which is similar to the base material. In order to verify the applicability of the method, some previously T-welded sheets were straightened. The method was efficient in correcting the distortion of the sheets with a bending angle up to 5°.

Magnetic field control of 90 Degree-Sign , 180 Degree-Sign , and 360 Degree-Sign domain wall resistance

Energy Technology Data Exchange (ETDEWEB)

Majidi, Roya, E-mail: royamajidi@gmail.com [Department of Physics, Shahid Rajaee Teacher Training University, Lavizan, 16788-15811 Tehran (Iran, Islamic Republic of)

2012-10-01

In the present work, we have compared the resistance of the 90 Degree-Sign , 180 Degree-Sign , and 360 Degree-Sign domain walls in the presence of external magnetic field. The calculations are based on the Boltzmann transport equation within the relaxation time approximation. One-dimensional Neel-type domain walls between two domains whose magnetization differs by angle of 90 Degree-Sign , 180 Degree-Sign , and 360 Degree-Sign are considered. The results indicate that the resistance of the 360 Degree-Sign DW is more considerable than that of the 90 Degree-Sign and 180 Degree-Sign DWs. It is also found that the domain wall resistance can be controlled by applying transverse magnetic field. Increasing the strength of the external magnetic field enhances the domain wall resistance. In providing spintronic devices based on magnetic nanomaterials, considering and controlling the effect of domain wall on resistivity are essential.

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.

Thermal conductivity of bulk boron nitride nanotube sheets and their epoxy-impregnated composites

International Nuclear Information System (INIS)

Jakubinek, Michael B.; Kim, Keun Su; Simard, Benoit; Niven, John F.; Johnson, Michel B.; Ashrafi, Behnam; White, Mary Anne

2016-01-01

The thermal conductivity of bulk, self-supporting boron nitride nanotube (BNNT) sheets composed of nominally 100% BNNTs oriented randomly in-plane was measured by a steady-state, parallel thermal conductance method. The sheets were either collected directly during synthesis or produced by dispersion and filtration. Differences between the effective thermal conductivities of filtration-produced BNNT buckypaper (∝1.5 W m -1 K -1 ) and lower-density as-synthesized sheets (∝0.75 W m -1 K -1 ), which are both porous materials, were primarily due to their density. The measured results indicate similar thermal conductivity, in the range of 7-12 W m -1 K -1 , for the BNNT network in these sheets. High BNNT-content composites (∝30 wt.% BNNTs) produced by epoxy impregnation of the porous BNNT network gave 2-3 W m -1 K -1 , more than 10 x the baseline epoxy. The combination of manufacturability, thermal conductivity, and electrical insulation offers exciting potential for electrically insulating, thermally conductive coatings and packaging. Thermal conductivity of free-standing BNNT buckypaper, buckypaper composites, and related materials at room temperature. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

On the Use of Maximum Force Criteria to Predict Localised Necking in Metal Sheets under Stretch-Bending

Directory of Open Access Journals (Sweden)

Domingo Morales-Palma

2017-11-01

Full Text Available The maximum force criteria and their derivatives, the Swift and Hill criteria, have been extensively used in the past to study sheet formability. Many extensions or modifications of these criteria have been proposed to improve necking predictions under only stretching conditions. This work analyses the maximum force principle under stretch-bending conditions and develops two different approaches to predict necking. The first is a generalisation of classical maximum force criteria to stretch-bending processes. The second approach is an extension of a previous work of the authors based on critical distance concepts, suggesting that necking of the sheet is controlled by the damage of a critical material volume located at the inner side of the sheet. An analytical deformation model is proposed to characterise the stretch-bending process under plane-strain conditions. Different parameters are considered, such as the thickness reduction, the gradient of variables through the sheet thickness, the thickness stress and the anisotropy of the material. The proposed necking models have been successfully applied to predict the failure in different materials, such as steel, brass and aluminium.

The stretch zone of automotive steel sheets

Indian Academy of Sciences (India)

The stretch zone of automotive steel sheets. L' AMBRIŠKO1,∗ and L PEŠEK2. 1Institute of Structural Engineering, Faculty of Civil Engineering,. Technical University of Košice, Vysokoškolská 4, 042 00 Košice, Slovak Republic. 2Department of Materials Science, Faculty of Metallurgy,. Technical University of Košice, Letná 9, ...

Hydrogen bonding-assisted thermal conduction in β-sheet crystals of spider silk protein

Science.gov (United States)

Zhang, Lin; Chen, Teli; Ban, Heng; Liu, Ling

2014-06-01

Using atomistic simulations, we demonstrate that β-sheet, an essential component of spider silk protein, has a thermal conductivity 1-2 orders of magnitude higher than that of some other protein structures reported in the literature. In contrast to several other nanostructured materials of similar bundled/layered structures (e.g. few-layer graphene and bundled carbon nanotubes), the β-sheet is found to uniquely feature enhanced thermal conductivity with an increased number of constituting units, i.e. β-strands. Phonon analysis identifies inter-β-strand hydrogen bonding as the main contributor to the intriguing phenomenon, which prominently influences the state of phonons in both low- and high-frequency regimes. A thermal resistance model further verifies the critical role of hydrogen bonding in thermal conduction through β-sheet structures.Using atomistic simulations, we demonstrate that β-sheet, an essential component of spider silk protein, has a thermal conductivity 1-2 orders of magnitude higher than that of some other protein structures reported in the literature. In contrast to several other nanostructured materials of similar bundled/layered structures (e.g. few-layer graphene and bundled carbon nanotubes), the β-sheet is found to uniquely feature enhanced thermal conductivity with an increased number of constituting units, i.e. β-strands. Phonon analysis identifies inter-β-strand hydrogen bonding as the main contributor to the intriguing phenomenon, which prominently influences the state of phonons in both low- and high-frequency regimes. A thermal resistance model further verifies the critical role of hydrogen bonding in thermal conduction through β-sheet structures. Electronic supplementary information (ESI) available: Structure of the β-sheets, computational model, determination of area and temperature gradient, and additional phonon DOS results. See DOI: 10.1039/c4nr01195c

Observations on Mode I ductile tearing in sheet metals

DEFF Research Database (Denmark)

El-Naaman, Salim Abdallah; Nielsen, Kim Lau

2013-01-01

Cracked ductile sheet metals, subject to Mode I tearing, have been observed to display a variety of fracture surface morphologies depending on the material properties, and a range of studies on the fracture surface appearance have been published in the literature. Whereas classical fractures...

Compression deformation behaviors of sheet metals at various clearances and side forces

OpenAIRE

Zhan Mei; Wang Xianxian; Cao Jian; Yang He

2015-01-01

Modeling sheet metal forming operations requires understanding of plastic behaviors of sheet metals along non-proportional strain paths. The plastic behavior under reversed uniaxial loading is of particular interest because of its simplicity of interpretation and its application to material elements drawn over a die radius and underwent repeated bending. However, the attainable strain is limited by failures, such as buckling and in-plane deformation, dependent on clearances and side forces. I...

Lubricant Test Methods for Sheet Metal Forming

DEFF Research Database (Denmark)

Bay, Niels; Olsson, David Dam; Andreasen, Jan Lasson

2008-01-01

appearing in different sheet forming operations such as stretch forming, deep drawing, ironing and punching. The laboratory tests have been especially designed to model the conditions in industrial production. Application of the tests for evaluating new lubricants before introducing them in production has......Sheet metal forming of tribologically difficult materials such as stainless steel, Al-alloys and Ti-alloys or forming in tribologically difficult operations like ironing, punching or deep drawing of thick plate requires often use of environmentally hazardous lubricants such as chlorinated paraffin...... oils in order to avoid galling. The present paper describes a systematic research in the development of new, environmentally harmless lubricants focusing on the lubricant testing aspects. A system of laboratory tests has been developed to study the lubricant performance under the very varied conditions...

The Effect of Grinding and Polishing Procedure of Tool Steels in Sheet Metal Forming

DEFF Research Database (Denmark)

Lindvall, F.; Bergström, J.; Krakhmalev, P.

2010-01-01

The surface finish of tools in sheet metal forming has a large influence on the performance of the forming tool. Galling, concern of wear in sheet metal forming, is a severe form of adhesive wear where sheet material is transferred on to the tool surface. By polishing the tools to a fine surface ...... 40 and Vanadis 6 and up to ten different grinding and polishing treatments were tested against AISI 316 stainless steel. The tests showed that an optimum surface preparation might be found at the transition between abrasive and adhesive wear....

Benchmark Testing of the Largest Titanium Aluminide Sheet Subelement Conducted

Science.gov (United States)

Bartolotta, Paul A.; Krause, David L.

2000-01-01

To evaluate wrought titanium aluminide (gamma TiAl) as a viable candidate material for the High-Speed Civil Transport (HSCT) exhaust nozzle, an international team led by the NASA Glenn Research Center at Lewis Field successfully fabricated and tested the largest gamma TiAl sheet structure ever manufactured. The gamma TiAl sheet structure, a 56-percent subscale divergent flap subelement, was fabricated for benchmark testing in three-point bending. Overall, the subelement was 84-cm (33-in.) long by 13-cm (5-in.) wide by 8-cm (3-in.) deep. Incorporated into the subelement were features that might be used in the fabrication of a full-scale divergent flap. These features include the use of: (1) gamma TiAl shear clips to join together sections of corrugations, (2) multiple gamma TiAl face sheets, (3) double hot-formed gamma TiAl corrugations, and (4) brazed joints. The structural integrity of the gamma TiAl sheet subelement was evaluated by conducting a room-temperature three-point static bend test.

Enhanced mechanical properties of ARB-processed aluminum alloy 6061 sheets by subsequent asymmetric cryorolling and ageing

International Nuclear Information System (INIS)

Yu, Hailiang; Su, Lihong; Lu, Cheng; Tieu, Kiet; Li, Huijun; Li, Jintao; Godbole, Ajit; Kong, Charlie

2016-01-01

Grain size and precipitations affect the strength and ductility of ultrafine-grained materials. In this study, aluminum alloy 6061 sheets were fabricated using the accumulative roll bonding (ARB) technique. The ARB-processed sheets were subsequently subjected to cryorolling and asymmetric cryorolling. The sheets were further aged at 100 °C for 48 h. Mechanical tests show that a combination of asymmetric cryorolling and ageing results in significant improvement in both the ductility and the strength of the ARB-processed sheets. The microstructures of the sheets at different stages of the process were also analyzed using optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction in order to correlate the mechanical properties with the microstructure.

Enhanced mechanical properties of ARB-processed aluminum alloy 6061 sheets by subsequent asymmetric cryorolling and ageing

Energy Technology Data Exchange (ETDEWEB)

Yu, Hailiang, E-mail: hailiang@uow.edu.au [State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083 (China); School of Mechanical, Materials & Mechatronics Engineering, University of Wollongong, NSW 2500 (Australia); Su, Lihong; Lu, Cheng; Tieu, Kiet [School of Mechanical, Materials & Mechatronics Engineering, University of Wollongong, NSW 2500 (Australia); Li, Huijun, E-mail: huijun@uow.edu.au [School of Mechanical, Materials & Mechatronics Engineering, University of Wollongong, NSW 2500 (Australia); Li, Jintao; Godbole, Ajit [School of Mechanical, Materials & Mechatronics Engineering, University of Wollongong, NSW 2500 (Australia); Kong, Charlie [Electron Microscope Unit, University of New South Wales, Sydney, NSW 2052 (Australia)

2016-09-30

Grain size and precipitations affect the strength and ductility of ultrafine-grained materials. In this study, aluminum alloy 6061 sheets were fabricated using the accumulative roll bonding (ARB) technique. The ARB-processed sheets were subsequently subjected to cryorolling and asymmetric cryorolling. The sheets were further aged at 100 °C for 48 h. Mechanical tests show that a combination of asymmetric cryorolling and ageing results in significant improvement in both the ductility and the strength of the ARB-processed sheets. The microstructures of the sheets at different stages of the process were also analyzed using optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction in order to correlate the mechanical properties with the microstructure.

Photovoltaics Fact Sheet

Energy Technology Data Exchange (ETDEWEB)

None

2016-02-01

This fact sheet is an overview of the Photovoltaics (PV) subprogram at the U.S. Department of Energy SunShot Initiative. The U.S. Department of Energy (DOE)’s Solar Energy Technologies Office works with industry, academia, national laboratories, and other government agencies to advance solar PV, which is the direct conversion of sunlight into electricity by a semiconductor, in support of the goals of the SunShot Initiative. SunShot supports research and development to aggressively advance PV technology by improving efficiency and reliability and lowering manufacturing costs. SunShot’s PV portfolio spans work from early-stage solar cell research through technology commercialization, including work on materials, processes, and device structure and characterization techniques.

Your Official U.S. Constitution Sign-On Information and Documents.

Science.gov (United States)

National Conference of Christians and Jews, New York, NY.

These learning materials are centered around the idea that each individual should "sign" the U.S. Constitution. A facsimile of the U.S. Constitution is included in each learning packet for students to sign. Section 1 contains five teaching modules on the constitutional process that can be used with any subject. The first two modules,…

Numerical analysis of tailored sheets to improve the quality of components made by SPIF

Science.gov (United States)

Gagliardi, Francesco; Ambrogio, Giuseppina; Cozza, Anna; Pulice, Diego; Filice, Luigino

2018-05-01

In this paper, the authors pointed out a study on the profitable combination of forming techniques. More in detail, the attention has been put on the combination of the single point incremental forming (SPIF) and, generally, speaking, of an additional process that can lead to a material thickening on the initial blank considering the local thinning which the sheets undergo at. Focalizing the attention of the research on the excessive thinning of parts made by SPIF, a hybrid approach can be thought as a viable solution to reduce the not homogeneous thickness distribution of the sheet. In fact, the basic idea is to work on a blank previously modified by a deformation step performed, for instance, by forming, additive or subtractive processes. To evaluate the effectiveness of this hybrid solution, a FE numerical model has been defined to analyze the thickness variation on tailored sheets incrementally formed optimizing the material distribution according to the shape to be manufactured. Simulations based on the explicit formulation have been set up for the model implementation. The mechanical properties of the sheet material have been taken in literature and a frustum of cone as benchmark profile has been considered for the performed analysis. The outcomes of numerical model have been evaluated in terms of both maximum thinning and final thickness distribution. The feasibility of the proposed approach will be deeply detailed in the paper.

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

Monitoring dc stray current corrosion at sheet pile structures

NARCIS (Netherlands)

Peelen, W.H.A.; Neeft, E.A.C.; Leegwater, G.; Kanten-Roos, W. van; Courage, W.M.G.

2012-01-01

Steel is discarded by railway owners as a material for underground structures near railway lines, due to uncertainty over increased corrosion by DC stray currents stemming from the traction power system. This paper presents a large scale field test in which stray currents interference of a sheet

Occurrence and location of concentrated load and generator regions observed by Cluster in the plasma sheet

Directory of Open Access Journals (Sweden)

M. Hamrin

2009-11-01

Full Text Available Here, and in a companion paper by Hamrin et al. (2009 [Scale size and life time of energy conversion regions observed by Cluster in the plasma sheet], we investigate localized energy conversion regions (ECRs in the Earth's plasma sheet. In total we have studied 151 ECRs within 660 h of plasma sheet data from the summer and fall of 2001 when Cluster was close to apogee at an altitude of about 15–20 R_E. Cluster offers appropriate conditions for the investigation of energy conversion by the evaluation of the power density, E·J, where E is the electric field and J the current density. From the sign of the power density, we have identified more than three times as many Concentrated Load Regions (CLRs as Concentrated Generator Regions (CGRs. We also note that the CLRs appear to be stronger. To our knowledge, these are the first in situ observations confirming the general notion of the plasma sheet, on the average, behaving as a load. At the same time the plasma sheet appears to be highly structured, with energy conversion occurring in both directions between the fields and the particles. From our data we also find that the CLRs appear to be located closer to the neutral sheet, while CGRs prefer locations towards the plasma sheet boundary layer (PSBL. For both CLRs and CGRs, E and J in the GSM y (cross-tail direction dominate the total power density, even though the z contribution occasionally can be significant. The prevalence of the y-direction seems to be weaker for the CGRs, possibly related to a higher fluctuation level near the PSBL.

MIXED SIGNS IN THE SEMIOTICS OF ENGLISH EDUCATIONAL DISCOURSE

Directory of Open Access Journals (Sweden)

Goncharova Darya Anatolyevna

2014-11-01

Full Text Available The article deals with the linguosemiotic explication of nomination process in educational discourse by signs of different types – verbal, non-verbal, mixed. Verbal signs are presented by lexical units, nominating agents, clients, non/material resources, artifacts, processes, incentives and forms of pedagogical influence. The non-verbal signs include paralinguistic signs (gestures, facial expressions, postures of the participants of the educational process; color-semiotic signs (coloremas, in which the information-impacting vector is directed to a color indication of messages that is important for successful educational communication; visual elements representing traditional British values and concepts; sound signs, topographic signs, that add meaning to the overall significance of a mixed sign. In linguosemiotic system of educational discourse, the mixed signs form the most numerous group and are represented mainly by emblems, anthems and school songs of secondary schools. The author checks and verifies the hypothesis that the semiotics of the educational process in British secondary schools includes the extensive and complex system of mixed signs, which consist of two non-homogeneous parts – verbal and non-verbal – belonging to other sign systems rather than natural language and expressed via graphics, colors, music, etc. Linguistic analysis is applied to the study of the semiotic space of educational discourse. The article determines that in the context of educational communication, verbal, non-verbal and mixed signs form the unity of the linguistic and extralinguistic parameters, being in different relationships and presenting a multilayer intersection of lexical groups, graphic description, color schemes and music accompaniment.

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.)

Practical Application of Sheet Lead for Sound Barriers.

Science.gov (United States)

Lead Industries Association, New York, NY.

Techniques for improving sound barriers through the use of lead sheeting are described. To achieve an ideal sound barrier a material should consist of the following properties--(1) high density, (2) freedom from stiffness, (3) good damping capacity, and (4) integrity as a non-permeable membrane. Lead combines these desired properties to a greater…

Study of a new X-ray protective apron with composite protective sheet

International Nuclear Information System (INIS)

Kanzaki, Ryuji; Ohtsuka, Akiyoshi; Okayama, Akio

1997-01-01

Lead powder and oxygenated lead are widely used as materials in conventional protective aprons. However, the use of lead alone limits weight reduction in an apron. Because the amount of lead can not be decreased without reducing X-ray absorption rate. In this study, we report the efficiency of a new X-ray protective apron with a composite protective sheet. The X-ray absorption rate of the composite sheet was 4.5 percent less than that of the lead sheet. However, the effective protective efficiency of the composite sheet was the same as that of the lead sheet. The uniformity of the new X-ray protective apron was good, and the differences among products were small. The new X-ray protective apron was about 30 percent lighter than a lead apron with a 0.25 mm lead equivalent. The new lighter aprons are more comfortable for the radiology staff. Therefore, the use of a composite protective apron provides the advantages of weight reduction and increased comfort without reducing X-ray absorption rate. (author)

Biscrolling nanotube sheets and functional guests into yarns

Science.gov (United States)

Baughman, Ray

2011-03-01

Multifunctional applications of textiles have been limited by the inability to spin important materials into yarns. Generically applicable methods are demonstrated for producing weavable yarns comprising up to 95 wt % of otherwise unspinnable particulate or nanofiber powders that remain highly functional. Scrolled 50 nm thick carbon nanotube sheets confine these powders in the galleries of irregular scroll sacks, whose observed complex structures are related to twist-dependent extension of Archimedean spirals, Fermat spirals, or spiral pairs into scrolls. The strength and electronic connectivity of a small weight fraction of scrolled carbon nanotube sheet enables yarn weaving, sewing, knotting, braiding, and charge collection. This technology is used to make yarns of superconductors, Li-ion battery materials, graphene ribbons, catalytic nanofibers for fuel cells, and Ti O2 for photocatalysis. Work done in collaboration with Shaoli Fang, Xavier Lepro-Chavez, Chihye Lewis, Raquel Ovalle-Robles, Javier Carratero-Gonzalez, Elisabet Castillo-Martinez, Mikhail Kozlov, Jiyoung Oh, Neema Rawat, Carter Haines, Mohammed Haque, Vaishnavi Aare, Stephanie Stoughton, Anvar Zakhidov, and Ray Baughman, The University of Texas at Dallas / Alan G. MacDiarmid NanoTech Institute.

Reducing the cost of MWT module technology based on conductive back-sheet foils

Energy Technology Data Exchange (ETDEWEB)

Bennett, I.J.; Goris, M.J.A.A.; Eerenstein, W. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands)

2013-10-15

MWT cell and module technology has shown to result in modules with a higher power output than H-pattern modules and to be suitable for use with thin and fragile cells. In this work, the use of low-cost module materials and their effect on module performance and reliability has been assessed. These materials include a conductive back-sheet patterned by milling with no silver plating at the contacts on the foil and no isolation coating on the copper and a low-silver content conductive adhesive. The sensitivity of module performance for the anti-corrosion coating on the copper of the conductive back-sheet is measured, as is the reliability in climate chamber testing of mini-modules made with these materials. The results show that these low cost materials can be used to manufacture module with good performance and reliability. Options are given for further cost reduction.

Investigation of the deformation stability in the incremental sheet forming process

Directory of Open Access Journals (Sweden)

Ai S.

2015-01-01

Full Text Available Incremental sheet forming (ISF is a highly versatile and flexible process for rapid manufacturing of complex sheet metal parts. One of the unique characters of the ISF process is the improved formability comparing to conventional sheet forming process. This may be due to the localized deformation nature, which increases the deformation stability in the ISF process. Although many hypotheses have been proposed, there is no direct modelling and calculation of the ISF deformation stability. Aiming to obtain a better understanding of the ISF process, an analytical model was developed to investigate and analyse the material deformation stability in this work. Based on the analytical evaluation of stress variations and force equilibrium, a mathematical relationship between the maximum forming angle and the process stability condition was established. To validate the developed model, experiments were carried out by forming a hyperbolic part made of AA1100 material. The maximum forming angle, as an indicator to the ISF formability, was employed compare the analytical evaluation and experimental result. It was found that the ISF deformation stability is one of the key factors that affect the ISF formability.

Human platelet lysate supports the formation of robust human periodontal ligament cell sheets.

Science.gov (United States)

Tian, Bei-Min; Wu, Rui-Xin; Bi, Chun-Sheng; He, Xiao-Tao; Yin, Yuan; Chen, Fa-Ming

2018-04-01

The use of stem cell-derived sheets has become increasingly common in a wide variety of biomedical applications. Although substantial evidence has demonstrated that human platelet lysate (PL) can be used for therapeutic cell expansion, either as a substitute for or as a supplement to xenogeneic fetal bovine serum (FBS), its impact on cell sheet production remains largely unexplored. In this study, we manufactured periodontal ligament stem cell (PDLSC) sheets in vitro by incubating PDLSCs in sheet-induction media supplemented with various ratios of PL and FBS, i.e. 10% PL without FBS, 7.5% PL + 2.5% FBS, 5% PL + 5% FBS, 2.5% PL + 7.5% FBS or 10% FBS without PL. Cultures with the addition of all the designed supplements led to successful cell sheet production. In addition, all the resultant cellular materials exhibited similar expression profiles of matrix-related genes and proteins, such as collagen I, fibronectin and integrin β1. Interestingly, the cell components within sheets generated by media containing both PL and FBS exhibited improved osteogenic potential. Following in vivo transplantation, all sheets supported significant new bone formation. Our data suggest that robust PDLSC sheets can be produced by applying PL as either an alternative or an adjuvant to FBS. Further examination of the relevant influences of human PL that benefit cell behaviour and matrix production will pave the way towards optimized and standardized conditions for cell sheet production. Copyright © 2017 John Wiley & Sons, Ltd.

Prediction of formability of aluminum alloy 5454 sheet

International Nuclear Information System (INIS)

Kim, Chan Il; Yang, Seung Han; Kim, Young Suk

2012-01-01

In the automobile industry, reducing the weight is the most important objective for reducing air pollution and improving the fuel efficiency. For this reason, the application of aluminum sheets is increasing. When the sheets are applied to the automobile, using inappropriate variables for the material, product design, and press processing can generate tearing, wrinkling, and spring back problems, which are the main types of failure in the manufacturing process. Therefore, it is necessary to reduce these failures by harmonizing the many variables and strictly managing the processes. In this research, we study the theoretical plasticity instability of Al5454 and obtain the forming limit diagram (FLD) using MATLAB. Moreover, we compare the theoretical FLD with an experimental FLD obtained from a stretching test

Comparison of Swirl Sign and Black Hole Sign in Predicting Early Hematoma Growth in Patients with Spontaneous Intracerebral Hemorrhage.

Science.gov (United States)

Xiong, Xin; Li, Qi; Yang, Wen-Song; Wei, Xiao; Hu, Xi; Wang, Xing-Chen; Zhu, Dan; Li, Rui; Cao, Du; Xie, Peng

2018-01-29

BACKGROUND Early hematoma growth is associated with poor outcome in patients with spontaneous intracerebral hemorrhage (ICH). The swirl sign (SS) and the black hole sign (BHS) are imaging markers in ICH patients. The aim of this study was to compare the predictive value of these 2 signs for early hematoma growth. MATERIAL AND METHODS ICH patients were screened for the appearance of the 2 signs within 6 h after onset of symptoms. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the 2 signs in predicting early hematoma growth were assessed. The accuracy of the 2 signs in predicting early hematoma growth was analyzed by receiver-operator analysis. RESULTS A total of 200 patients were enrolled in this study. BHS was found in 30 (15%) patients, and SS was found in 70 (35%) patients. Of the 71 patients with early hematoma growth, BHS was found on initial computed tomography scans in 24 (33.8%) and SS in 33 (46.5%). The sensitivity, specificity, PPV, and NPV of BHS for predicting early hematoma growth were 33.8%, 95.3%, 80.0%, and 72.0%, respectively. The sensitivity, specificity, PPV, and NPV of SS were 46.5%, 71.3%, 47.0%, and 71.0%, respectively. The area under the curve was 0.646 for BHS and 0.589 for SS (P=0.08). Multivariate logistic regression showed that presence of BHS is an independent predictor of early hematoma growth. CONCLUSIONS The Black hole sign seems to be good predictor for hematoma growth. The presence of swirl sign on admission CT does not independently predict hematoma growth in patients with ICH.

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

Face-Sheet Quality Analysis and Thermo-Physical Property Characterization of OOA and Autoclave Panels

Science.gov (United States)

Miller, Sandi G.; Lort, Richard D., III; Zimmerman, Thomas J.; Sutter, James K.; Pelham, Larry I.; McCorkle, Linda S.; Scheiman, Daniel A.

2012-01-01

Increased application of polymer matrix composite (PMC) materials in large vehicle structures requires consideration of non-autoclave manufacturing technology. The NASA Composites for Exploration project, and its predecessor, Lightweight Spacecraft Structures and Materials project, were tasked with the development of materials and manufacturing processes for structures that will perform in a heavy-lift-launch vehicle environment. Both autoclave and out of autoclave processable materials were considered. Large PMC structures envisioned for such a vehicle included the payload shroud and the interstage connector. In this study, composite sandwich panels representing 1/16th segments of the barrel section of the Ares V rocket fairing were prepared as 1.8 m x 2.4 m sections of the 10 m diameter arc segment. IM7/977-3 was used as the face-sheet prepreg of the autoclave processed panels and T40-800B/5320-1 for the out of autoclave panels. The core was 49.7 kg/sq m (3.1 lb/cu ft (pcf)) aluminum honeycomb. Face-sheets were fabricated by automated tape laying 153 mm wide unidirectional tape. This work details analysis of the manufactured panels where face-sheet quality was characterized by optical microscopy, cured ply thickness measurements, acid digestion, and thermal analysis.

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

Ergonomics and design: traffic sign and street name sign.

Science.gov (United States)

Moroni, Janaina Luisa da Silva; Aymone, José Luís Farinatti

2012-01-01

This work proposes a design methodology using ergonomics and anthropometry concepts applied to traffic sign and street name sign projects. Initially, a literature revision on cognitive ergonomics and anthropometry is performed. Several authors and their design methodologies are analyzed and the aspects to be considered in projects of traffic and street name signs are selected and other specific aspects are proposed for the design methodology. A case study of the signs of "Street of Antiques" in Porto Alegre city is presented. To do that, interviews with the population are made to evaluate the current situation of signs. After that, a new sign proposal with virtual prototyping is done using the developed methodology. The results obtained with new interviews about the proposal show the user satisfaction and the importance of cognitive ergonomics to development of this type of urban furniture.

Sign language comprehension: the case of Spanish sign language.

Science.gov (United States)

Rodríguez Ortiz, I R

2008-01-01

This study aims to answer the question, how much of Spanish Sign Language interpreting deaf individuals really understand. Study sampling included 36 deaf people (deafness ranging from severe to profound; variety depending on the age at which they learned sign language) and 36 hearing people who had good knowledge of sign language (most were interpreters). Sign language comprehension was assessed using passages of secondary level. After being exposed to the passages, the participants had to tell what they had understood about them, answer a set of related questions, and offer a title for the passage. Sign language comprehension by deaf participants was quite acceptable but not as good as that by hearing signers who, unlike deaf participants, were not only late learners of sign language as a second language but had also learned it through formal training.

Synergistic Effect between Ultra-Small Nickel Hydroxide Nanoparticles and Reduced Graphene Oxide sheets for the Application in High-Performance Asymmetric Supercapacitor.

Science.gov (United States)

Liu, Yonghuan; Wang, Rutao; Yan, Xingbin

2015-06-08

Nanoscale electrode materials including metal oxide nanoparticles and two-dimensional graphene have been employed for designing supercapacitors. However, inevitable agglomeration of nanoparticles and layers stacking of graphene largely hamper their practical applications. Here we demonstrate an efficient co-ordination and synergistic effect between ultra-small Ni(OH)2 nanoparticles and reduced graphene oxide (RGO) sheets for synthesizing ideal electrode materials. On one hand, to make the ultra-small Ni(OH)2 nanoparticles work at full capacity as an ideal pseudocapacitive material, RGO sheets are employed as an suitable substrate to anchor these nanoparticles against agglomeration. As a consequence, an ultrahigh specific capacitance of 1717 F g(-1) at 0.5 A g(-1) is achieved. On the other hand, to further facilitate ion transfer within RGO sheets as an ideal electrical double layer capacitor material, the ultra-small Ni(OH)2 nanoparticles are introduced among RGO sheets as the recyclable sacrificial spacer to prevent the stacking. The resulting RGO sheets exhibit superior rate capability with a high capacitance of 182 F g(-1) at 100 A g(-1). On this basis, an asymmetric supercapacitor is assembled using the two materials, delivering a superior energy density of 75 Wh kg(-1) and an ultrahigh power density of 40 000 W kg(-1).

Process control for sheet-metal stamping process modeling, controller design and shop-floor implementation

CERN Document Server

Lim, Yongseob; Ulsoy, A Galip

2014-01-01

Process Control for Sheet-Metal Stamping presents a comprehensive and structured approach to the design and implementation of controllers for the sheet metal stamping process. The use of process control for sheet-metal stamping greatly reduces defects in deep-drawn parts and can also yield large material savings from reduced scrap. Sheet-metal forming is a complex process and most often characterized by partial differential equations that are numerically solved using finite-element techniques. In this book, twenty years of academic research are reviewed and the resulting technology transitioned to the industrial environment. The sheet-metal stamping process is modeled in a manner suitable for multiple-input multiple-output control system design, with commercially available sensors and actuators. These models are then used to design adaptive controllers and real-time controller implementation is discussed. Finally, experimental results from actual shopfloor deployment are presented along with ideas for further...

Thermal conductivity of bulk boron nitride nanotube sheets and their epoxy-impregnated composites

Energy Technology Data Exchange (ETDEWEB)

Jakubinek, Michael B.; Kim, Keun Su; Simard, Benoit [Security and Disruptive Technologies, Division of Emerging Technologies, National Research Council Canada, Ottawa, ON (Canada); Niven, John F. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS (Canada); Johnson, Michel B. [Institute for Research in Materials, Dalhousie University, Halifax, NS (Canada); Ashrafi, Behnam [Aerospace, Division of Engineering, National Research Council Canada, Montreal, QC (Canada); White, Mary Anne [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS (Canada); Institute for Research in Materials, Dalhousie University, Halifax, NS (Canada); Department of Chemistry, Dalhousie University, Halifax, NS (Canada)

2016-08-15

The thermal conductivity of bulk, self-supporting boron nitride nanotube (BNNT) sheets composed of nominally 100% BNNTs oriented randomly in-plane was measured by a steady-state, parallel thermal conductance method. The sheets were either collected directly during synthesis or produced by dispersion and filtration. Differences between the effective thermal conductivities of filtration-produced BNNT buckypaper (∝1.5 W m{sup -1} K{sup -1}) and lower-density as-synthesized sheets (∝0.75 W m{sup -1} K{sup -1}), which are both porous materials, were primarily due to their density. The measured results indicate similar thermal conductivity, in the range of 7-12 W m{sup -1} K{sup -1}, for the BNNT network in these sheets. High BNNT-content composites (∝30 wt.% BNNTs) produced by epoxy impregnation of the porous BNNT network gave 2-3 W m{sup -1} K{sup -1}, more than 10 x the baseline epoxy. The combination of manufacturability, thermal conductivity, and electrical insulation offers exciting potential for electrically insulating, thermally conductive coatings and packaging. Thermal conductivity of free-standing BNNT buckypaper, buckypaper composites, and related materials at room temperature. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Thermal conductivity of a two-dimensional phosphorene sheet: a comparative study with graphene.

Science.gov (United States)

Hong, Yang; Zhang, Jingchao; Huang, Xiaopeng; Zeng, Xiao Cheng

2015-11-28

A recently discovered two-dimensional (2D) layered material phosphorene has attracted considerable interest as a promising p-type semiconducting material. In this work, thermal conductivity (κ) of monolayer phosphorene is calculated using large-scale classical non-equilibrium molecular dynamics (NEMD) simulations. The predicted thermal conductivities for infinite length armchair and zigzag phosphorene sheets are 63.6 and 110.7 W m(-1) K(-1) respectively. The strong anisotropic thermal transport is attributed to the distinct atomic structures at altered chiral directions and direction-dependent group velocities. Thermal conductivities of 2D graphene sheets with the same dimensions are also computed for comparison. The extrapolated κ of the 2D graphene sheet are 1008.5(+37.6)(-37.6) and 1086.9(+59.1)(-59.1) W m(-1) K(-1) in the armchair and zigzag directions, respectively, which are an order of magnitude higher than those of phosphorene. The overall and decomposed phonon density of states (PDOS) are calculated in both structures to elucidate their thermal conductivity differences. In comparison with graphene, the vibrational frequencies that can be excited in phosphorene are severely limited. The temperature effect on the thermal conductivity of phosphorene and graphene sheets is investigated, which reveals a monotonic decreasing trend for both structures.

Design and Optimization of Sheet Hydroforming Process for Manufacturing Oil tank

International Nuclear Information System (INIS)

Prakash, C.; Narasimhan, K.

2005-01-01

The need for reduction of weight is an important issue in sheet metal forming industry. The hydroforming process has become an effective manufacturing process, as it can be adapted for the manufacturing of complex structural components with high structural stiffness. The process parameters and material properties are important factors that influence the quality of final product. In this paper, an optimized window of process parameters is obtained for successful sheet hydroforming of Oil tank. The simulation of hydroforming process is performed by using a Finite Element Method based Commercial code

Single crystalline electronic structure and growth mechanism of aligned square graphene sheets

Science.gov (United States)

Yang, H. F.; Chen, C.; Wang, H.; Liu, Z. K.; Zhang, T.; Peng, H.; Schröter, N. B. M.; Ekahana, S. A.; Jiang, J.; Yang, L. X.; Kandyba, V.; Barinov, A.; Chen, C. Y.; Avila, J.; Asensio, M. C.; Peng, H. L.; Liu, Z. F.; Chen, Y. L.

2018-03-01

Recently, commercially available copper foil has become an efficient and inexpensive catalytic substrate for scalable growth of large-area graphene films for fundamental research and applications. Interestingly, despite its hexagonal honeycomb lattice, graphene can be grown into large aligned square-shaped sheets on copper foils. Here, by applying angle-resolved photoemission spectroscopy with submicron spatial resolution (micro-ARPES) to study the three-dimensional electronic structures of square graphene sheets grown on copper foils, we verified the high quality of individual square graphene sheets as well as their merged regions (with aligned orientation). Furthermore, by simultaneously measuring the graphene sheets and their substrate copper foil, we not only established the (001) copper surface structure but also discovered that the square graphene sheets' sides align with the ⟨110⟩ copper direction, suggesting an important role of copper substrate in the growth of square graphene sheets—which will help the development of effective methods to synthesize high-quality large-size regularly shaped graphene sheets for future applications. This work also demonstrates the effectiveness of micro-ARPES in exploring low-dimensional materials down to atomic thickness and sub-micron lateral size (e.g., besides graphene, it can also be applied to transition metal dichalcogenides and various van der Waals heterostructures)

Headaches - danger signs

Science.gov (United States)

Migraine headache - danger signs; Tension headache - danger signs; Cluster headache - danger signs; Vascular headache - danger signs ... and other head pain. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine . 25th ed. Philadelphia, PA: ...

Bridged graphite oxide materials

Science.gov (United States)

Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

2010-01-01

Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

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.

Stable subcutaneous cartilage regeneration of bone marrow stromal cells directed by chondrocyte sheet.

Science.gov (United States)

Li, Dan; Zhu, Lian; Liu, Yu; Yin, Zongqi; Liu, Yi; Liu, Fangjun; He, Aijuan; Feng, Shaoqing; Zhang, Yixin; Zhang, Zhiyong; Zhang, Wenjie; Liu, Wei; Cao, Yilin; Zhou, Guangdong

2017-05-01

In vivo niche plays an important role in regulating differentiation fate of stem cells. Due to lack of proper chondrogenic niche, stable cartilage regeneration of bone marrow stromal cells (BMSCs) in subcutaneous environments is always a great challenge. This study explored the feasibility that chondrocyte sheet created chondrogenic niche retained chondrogenic phenotype of BMSC engineered cartilage (BEC) in subcutaneous environments. Porcine BMSCs were seeded into biodegradable scaffolds followed by 4weeks of chondrogenic induction in vitro to form BEC, which were wrapped with chondrocyte sheets (Sheet group), acellular small intestinal submucosa (SIS, SIS group), or nothing (Blank group) respectively and then implanted subcutaneously into nude mice to trace the maintenance of chondrogenic phenotype. The results showed that all the constructs in Sheet group displayed typical cartilaginous features with abundant lacunae and cartilage specific matrices deposition. These samples became more mature with prolonged in vivo implantation, and few signs of ossification were observed at all time points except for one sample that had not been wrapped completely. Cell labeling results in Sheet group further revealed that the implanted BEC directly participated in cartilage formation. Samples in both SIS and Blank groups mainly showed ossified tissue at all time points with partial fibrogenesis in a few samples. These results suggested that chondrocyte sheet could create a chondrogenic niche for retaining chondrogenic phenotype of BEC in subcutaneous environment and thus provide a novel research model for stable ectopic cartilage regeneration based on stem cells. In vivo niche plays an important role in directing differentiation fate of stem cells. Due to lack of proper chondrogenic niche, stable cartilage regeneration of bone marrow stromal cells (BMSCs) in subcutaneous environments is always a great challenge. The current study demonstrated that chondrocyte sheet generated by

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

Formability of aluminium sheets manufactured by solid state recycling

Science.gov (United States)

Kore, A. S.; Nayak, K. C.; Date, P. P.

2017-09-01

Conventional recycling practices for non-ferrous metallic scrap involves melting followed by purification. This practice is suitable for recycling when the large volume of scrap is available. Though such recycling reduces consumption of diminishing metallic resources, high energy requirement and material loss during melting and purification limit its applicability. In the present work, manufacturing of solid state recycled aluminium sheet by hot rolling is explored and its formability characterized. Aluminium chips were divided into smaller particles (1~2mm) by crushing. After stress relief annealing, chips were cold compacted into square slabs (75*75mm section) of different thicknesses. Another similar set of slabs was made by hot compaction. The compacted slabs were hot rolled over a number of passes at 400°C. Each slab was reduced to approximately 90% thickness to get the sheet thickness in the range of 0.6 to 1.5 mm. Microstructure revealed good interface bonding between the chip particles. Mechanical properties of the sheet from room temperature up to 200°C and at different strain rates were characterized by a number of tensile tests. Circular blanks from sheet were drawn into cylindrical cups and strain distribution was observed along different directions of rolling using circle grid analysis.

Sign language typology: The contribution of rural sign languages

NARCIS (Netherlands)

de Vos, C.; Pfau, R.

2015-01-01

Since the 1990s, the field of sign language typology has shown that sign languages exhibit typological variation at all relevant levels of linguistic description. These initial typological comparisons were heavily skewed toward the urban sign languages of developed countries, mostly in the Western

Equal-channel angular sheet extrusion of interstitial-free (IF) steel: Microstructural evolution and mechanical properties

International Nuclear Information System (INIS)

Saray, O.; Purcek, G.; Karaman, I.; Neindorf, T.; Maier, H.J.

2011-01-01

Highlights: → IF-steel sheets can successfully be processed in the continuous manner using the equal-channel angular sheet extrusion (ECASE). → The ECASE produces the microstructures including dislocation cell and micro-shear bands inside the grains with mainly low-angle grain boundaries. → The ECASE results in a considerable increase in the strength but limited ductility. → A good strength-ductility balance in the ECASE-processed IF-steel sheets can be managed with a suitable annealing parameters. - Abstract: Interstitial-free steel (IF-steel) sheets were processed at room temperature using a continuous severe plastic deformation (SPD) technique called equal-channel angular sheet extrusion (ECASE). After processing, the microstructural evolution and mechanical properties have been systematically investigated. To be able to directly compare the results with those from the same material processed using discontinuous equal channel angular extrusion, the sheets were ECASE processed up to eight passes. The microstructural investigations revealed that the processed sheets exhibited a dislocation cell and/or subgrain structures with mostly low angle grain boundaries. The grains after processing have relatively high dislocation density and intense micro-shear band formation. The electron backscattering diffraction (EBSD) examination showed that the processed microstructure is not fully homogeneous along the sheet thickness due probably to the corner angle of 120 deg. in the ECASE die. It was also observed that the strengths of the processed sheets increase with the number of ECASE passes, and after eight passes following route-A and route-C, the yield strengths reach 463 MPa and 459 MPa, respectively, which is almost 2.5 times higher than that of the initial material. However, the tensile ductility considerably dropped after the ECASE. The limited ductility was attributed to the early plastic instability in the tensile samples due to the inhomogeneous

Investigation into springback characteristics of two HSS sheets during cold v-bending

Energy Technology Data Exchange (ETDEWEB)

Fang, Gang; Gao, Wei-Ran [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

2013-12-16

Considering the safety and the light-weight structure, there is an increasing requirement of high strength steel (HSS) sheets in the automotive industry. The high-precise prediction of the springback depends on constitutive equations and their corresponding material parameters. In order to investigate the springback of HSS sheets, DP590 and B280VK, their constitutive behaviors were analyzed based on the sheet tension tests. With respect to the constitutive equation, the Voce model is more proper to two hot-rolled steels, DP590 and B280VK, than the Swift model. Two steels are all saturated hardening, and the degree of hardening decreases with the strain. The cold v-banding tests of two HSS sheets were carried out for evaluation of springback characteristics. Results of v-bending experiments showed that the springback angle increases with the bending along 45°, 90° and 0° to the rolling direction of steel in turn.

Investigation into springback characteristics of two HSS sheets during cold v-bending

International Nuclear Information System (INIS)

Fang, Gang; Gao, Wei-Ran

2013-01-01

Considering the safety and the light-weight structure, there is an increasing requirement of high strength steel (HSS) sheets in the automotive industry. The high-precise prediction of the springback depends on constitutive equations and their corresponding material parameters. In order to investigate the springback of HSS sheets, DP590 and B280VK, their constitutive behaviors were analyzed based on the sheet tension tests. With respect to the constitutive equation, the Voce model is more proper to two hot-rolled steels, DP590 and B280VK, than the Swift model. Two steels are all saturated hardening, and the degree of hardening decreases with the strain. The cold v-banding tests of two HSS sheets were carried out for evaluation of springback characteristics. Results of v-bending experiments showed that the springback angle increases with the bending along 45°, 90° and 0° to the rolling direction of steel in turn

VS4 Nanoparticles Anchored on Graphene Sheets as a High-Rate and Stable Electrode Material for Sodium Ion Batteries.

Science.gov (United States)

Pang, Qiang; Zhao, Yingying; Yu, Yanhao; Bian, Xiaofei; Wang, Xudong; Wei, Yingjin; Gao, Yu; Chen, Gang

2018-02-22

The size and conductivity of the electrode materials play a significant role in the kinetics of sodium-ion batteries. Various characterizations reveal that size-controllable VS 4 nanoparticles can be successfully anchored on the surface of graphene sheets (GSs) by a simple cationic-surfactant-assisted hydrothermal method. When used as an electrode material for sodium-ion batteries, these VS 4 @GS nanocomposites show large specific capacity (349.1 mAh g -1 after 100 cycles), excellent long-term stability (84 % capacity retention after 1200 cycles), and high rate capability (188.1 mAh g -1 at 4000 mA g -1 ). A large proportion of the capacity was contributed by capacitive processes. This remarkable electrochemical performance was attributed to synergistic interactions between nanosized VS 4 particles and a highly conductive graphene network, which provided short diffusion pathways for Na + ions and large contact areas between the electrolyte and electrode, resulting in considerably improved electrochemical kinetic properties. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Van der Waals epitaxy and photoresponse of hexagonal tellurium nanoplates on flexible mica sheets.

Science.gov (United States)

Wang, Qisheng; Safdar, Muhammad; Xu, Kai; Mirza, Misbah; Wang, Zhenxing; He, Jun

2014-07-22

Van der Waals epitaxy (vdWE) is of great interest due to its extensive applications in the synthesis of ultrathin two-dimensional (2D) layered materials. However, vdWE of nonlayered functional materials is still not very well documented. Here, although tellurium has a strong tendency to grow into one-dimensional nanoarchitecture due to its chain-like structure, we successfully realize 2D hexagonal tellurium nanoplates on flexible mica sheets via vdWE. Chemically inert mica surface is found to be crucial for the lateral growth of hexagonal tellurium nanoplates since it (1) facilitates the migration of tellurium adatoms along mica surface and (2) allows a large lattice mismatch. Furthermore, 2D tellurium hexagonal nanoplates-based photodetectors are in situ fabricated on flexible mica sheets. Efficient photoresponse is obtained even after bending the device for 100 times, indicating 2D tellurium hexagonal nanoplates-based photodetectors on mica sheets have a great application potential in flexible and wearable optoelectronic devices. We believe the fundamental understanding of vdWE effect on the growth of 2D tellurium hexagonal nanoplate can pave the way toward leveraging vdWE as a useful channel to realize the 2D geometry of other nonlayered materials.

Stiffness management of sheet metal parts using laser metal deposition

Science.gov (United States)

Bambach, Markus; Sviridov, Alexander; Weisheit, Andreas

2017-10-01

Tailored blanks are established solutions for the production of load-adapted sheet metal components. In the course of the individualization of production, such semi-finished products are gaining importance. In addition to tailored welded blanks and tailored rolled blanks, patchwork blanks have been developed which allow a local increase in sheet thickness by welding, gluing or soldering patches onto sheet metal blanks. Patchwork blanks, however, have several limitations, on the one hand, the limited freedom of design in the production of patchwork blanks and, on the other hand, the fact that there is no optimum material bonding with the substrate. The increasing production of derivative and special vehicles on the basis of standard vehicles, prototype production and the functionalization of components require solutions with which semi-finished products and sheet metal components can be provided flexibly with local thickenings or functional elements with a firm metallurgical bond to the substrate. An alternative to tailored and patchwork blanks is, therefore, a free-form reinforcement applied by additive manufacturing via laser metal deposition (LMD). By combining metal forming and additive manufacturing, stiffness can be adapted to the loads based on standard components in a material-efficient manner and without the need to redesign the forming tools. This paper details a study of the potential of stiffness management by LMD using a demonstrator part. Sizing optimization is performed and part distortion is taken into account to find an optimal design for the cladding. A maximum stiffness increase of 167% is feasible with only 4.7% additional mass. Avoiding part distortion leads to a pareto-optimal design which achieves 95% more stiffness with 6% added mass.

Microstructural and Mechanical Study of Press Hardening of Thick Boron Steel Sheet

Science.gov (United States)

Pujante, J.; Garcia-Llamas, E.; Golling, S.; Casellas, D.

2017-09-01

Press hardening has become a staple in the production of automotive safety components, due to the combination of high mechanical properties and form complexity it offers. However, the use of press hardened components has not spread to the truck industry despite the advantages it confers, namely affordable weight reduction without the use of exotic materials, would be extremely attractive for this sector. The main reason for this is that application of press hardened components in trucks implies adapting the process to the manufacture of thick sheet metal. This introduces an additional layer of complexity, mainly due to the thermal gradients inside the material resulting in though-thickness differences in austenitization and cooling, potentially resulting in complex microstructure and gradient of mechanical properties. This work presents a preliminary study on the press hardening of thick boron steel sheet. First of all, the evolution of the sheet metal during austenitization is studied by means of dilatometry tests and by analysing the effect of furnace dwell time on grain size. Afterwards, material cooled using different cooling strategies, and therefore different effective cooling rates, is studied in terms of microstructure and mechanical properties. Initial results from finite element simulation are compared to experimental results, focusing on the phase composition in through thickness direction. Results show that industrial-equivalent cooling conditions do not lead to gradient microstructures, even in extreme scenarios involving asymmetrical cooling.

Early Shear Failure Prediction in Incremental Sheet Forming Process Using FEM and ANN

Science.gov (United States)

Moayedfar, Majid; Hanaei, Hengameh; Majdi Rani, Ahmad; Musa, Mohd Azam Bin; Sadegh Momeni, Mohammad

2018-03-01

The application of incremental sheet forming process as a rapid forming technique is rising in variety of industries such as aerospace, automotive and biomechanical purposes. However, the sheet failure is a big challenge in this process which leads wasting lots of materials. Hence, this study tried to propose a method to predict the early sheet failure in this process using mathematical solution. For the feasibility of the study, design of experiment with the respond surface method is employed to extract a set of experiments data for the simulation. The significant forming parameters were recognized and their integration was used for prediction system. Then, the results were inserted to the artificial neural network as input parameters to predict a vast range of applicable parameters avoiding sheet failure in ISF. The value of accuracy R2 ∼0.93 was obtained and the maximum sheet stretch in the depth of 25mm were recorded. The figures generate from the trend of interaction between effective parameters were provided for future studies.

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

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.

Carbon-wrapped MnO nanodendrites interspersed on reduced graphene oxide sheets as anode materials for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Liu, Boli; Li, Dan; Liu, Zhengjiao; Gu, Lili; Xie, Wenhe; Li, Qun; Guo, Pengqian; Liu, Dequan; He, Deyan, E-mail: hedy@lzu.edu.cn

2017-02-01

Highlights: • The C-MnO/rGO composites were anchored on nickel foam by a facile vacuum filtration and a subsequent thermal treatment. • The novel architecture of anodes effectively improved the electrochemical performance of lithium ion battery. • The active MnO nanodendrites became smaller nanoparticles still wrapped in graphene sheets after cycles. - Abstract: Carbon-wrapped MnO nanodendrites interspersed on reduced graphene oxide sheets (C-MnO/rGO) were prepared on nickel foam by a facile vacuum filtration and a subsequent thermal treatment. As a binder-free anode of lithium-ion battery, the nanodendritic structure of C-MnO accommodates the huge volume expansion and shortens the diffusion length for lithium ion and electron, rGO sheets prevent C-MnO nanodendites from aggregation and offer a good electronic conduction. As a result, the electrode with such a novel architecture delivers superior electrochemical properties including high reversible capacity, excellent rate capability and cycle stability. Moreover, MnO nanodendrites change to nanoparticles wrapped in graphene sheets during the lithiation/delithiation process, which is a more beneficial microstructure to further increase the specific capacity and cycle life of the electrode.

An Investigation on Corrosion Behavior of a Multi-layer Modified Aluminum Brazing Sheet

Directory of Open Access Journals (Sweden)

Liu Wei

2016-01-01

Full Text Available The corrosion behavior of a multi-layer modified aluminum brazing sheet (AA4045/3003Mod./AA7072/AA4045 was investigated. The results shows that, the existence of BDP, which forms at the interface between clad and core layer during brazing, changes the corrosion form of the air side of the material from inter-granular corrosion to local exfoliation corrosion. The addition of anti-corrosion layer makes the corrosion form of the water side from inter-granular corrosion into uniform exfoliation corrosion. Compared to the normal triple-layer brazing sheet at the same thickness, the time to perforation of the modified four-layer brazing sheet is increased by more than 200%.

Effect of material scatter on the plastic behavior and stretchability in sheet metal forming

NARCIS (Netherlands)

Wiebenga, J.H.; Atzema, E.H.; Atzema, E.H.; An, Y.G.; Vegter, H.; van den Boogaard, Antonius H.

2014-01-01

Robust design of forming processes is gaining attention throughout the industry. To analyze the robustness of a sheet metal forming process using Finite Element (FE) simulations, an accurate input in terms of parameter scatter is required. This paper presents a pragmatic, accurate and economic

Consumer Products Containing Radioactive Materials

Science.gov (United States)

Fact Sheet Adopted: February 2010 Health Physics Society Specialists in Radiation Safety Consumer Products Containing Radioactive Materials Everything we encounter in our daily lives contains some radioactive material, ...

Malaysian sign language dataset for automatic sign language ...

African Journals Online (AJOL)

Journal of Fundamental and Applied Sciences. Journal Home · ABOUT ... SL recognition system based on the Malaysian Sign Language (MSL). Implementation results are described. Keywords: sign language; pattern classification; database.

Images in pediatrics: the thymic sail sign and thymic wave sign.

Science.gov (United States)

Alves, Nuno D; Sousa, Marta

2013-01-01

The authors present a radiographic image portraying the "thymic sail sign" and the "thymic wave sign," both normal findings in infant radiographs and present a short description of these signs. These are distinguished from pathologic findings such as the "spinnaker-sail sign" in pneumomediastinum.

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)

Joining of aluminum sheet and glass fiber reinforced polymer using extruded pins

Science.gov (United States)

Conte, Romina; Buhl, Johannes; Ambrogio, Giuseppina; Bambach, Markus

2018-05-01

The present contribution proposes a new approach for joining sheet metal and fiber reinforced composites. The joining process draws upon a Friction Stir Forming (FSF) process, which is performed on the metal sheet to produce slender pins. These pins are used to pierce through the composite. Joining is complete by forming a locking head out of the part if the pin sticks out of the composite. Pins of different diameters and lengths were produced from EN AW-1050 material, which were joined to glass fiber reinforced polyamide-6. The strength of the joint has been experimentally tested in order to understand the effect of the process temperature on the pins strength and therefore on the joining. The results demonstrate the feasibility of this new technique, which uses no excess material.

Evaluation of creep and relaxation data for hastelloy alloy x sheet

International Nuclear Information System (INIS)

Booker, M.K.

1979-02-01

Hastelloy alloy X has been a successful high-temperature structural material for more than two decades. Recently, Hastelloy alloy X sheet has been selected as a prime structural material for the proposed Brayton Isotope Power System (BIPS). The material also sees extensive application in the High-Temperature Gas-Cooled Reactor (HTGR). Design of these systems requires a detailed consideration of the high-temperature creep properties of this material. Therefore, available creep, creep-rupture, and relaxation data for Hastelloy alloy X were collected and analyzed to yield mathematical representations of the behavior for design use

Graphene materials having randomly distributed two-dimensional structural defects

Science.gov (United States)

Kung, Harold H; Zhao, Xin; Hayner, Cary M; Kung, Mayfair C

2013-10-08

Graphene-based storage materials for high-power battery applications are provided. The storage materials are composed of vertical stacks of graphene sheets and have reduced resistance for Li ion transport. This reduced resistance is achieved by incorporating a random distribution of structural defects into the stacked graphene sheets, whereby the structural defects facilitate the diffusion of Li ions into the interior of the storage materials.

Radiation protecting clothing materials

International Nuclear Information System (INIS)

Mio, Kotaro; Ijiri, Yasuo.

1986-01-01

Purpose: To provide radiation protecting clothing materials excellent in mechanical strength, corrosion resistance, flexibility and flexing strength. Constitution: The radiation protecting clothing materials according to this invention has pure lead sheets comprising a thin pure lead foil of 50 to 150 μm and radiation resistant organic materials, for example, polyethylene with high neutron shielding effect disposed to one or both surfaces thereof. The material are excellent in the repeating bending fatigue and mechanical strength, corrosion resistance and flexibility and, accordingly, radiation protecting clothings prepared by using them along or laminating them also possess these excellent characteristics. Further, they are excellent in the handlability, particularly, durability to the repeated holding and extension, as well as are preferable in the physical movability and feeling upon putting. The clothing materials may be cut into an appropriate size, or stitched into clothings made by radiation-resistant materials. In this case, pure lead sheets are used in lamination. (Horiuchi, T.)

75 FR 70289 - Certain Coated Paper Suitable For High-Quality Print Graphics Using Sheet-Fed Presses From China...

Science.gov (United States)

2010-11-17

...)] Certain Coated Paper Suitable For High-Quality Print Graphics Using Sheet-Fed Presses From China and... paper suitable for high-quality print graphics using sheet-fed presses (``certain coated paper'') from... paper industry is materially injured by reason of imports of the subject merchandise from China and...

The Relationship Between Depression And Positive Signs In Chronic Schizophrenia

Directory of Open Access Journals (Sweden)

Bahaoddini S S

2004-06-01

Full Text Available Background: The results of studies about relationship between depression and positive signs in schizophrenia are controversial and clarifying the nature of this association may be difficult. The aim of present study is to investigate relationship between depressive symptoms and positive signs, in acute phase of patients with chronic schizophrenia, who have been admitted in Roozbeh Hospital. Materials and Methods: Assessments were performed using the Beck depression Inventory for depression (subjectively and positive and negative syndrome scale (PANSS for psychotic symptoms. Results: The results demonstrated a significant correlation between depressive symptoms and positive signs in these patients. Also, a significant correlation existed between depression and these items: delusions, hallucinatory behavior, excitement, hostility. Conclusion: depressive symptoms and positive signs in schizophrenia may have a common underlying pathophysiological origin.

On the System of Place Name Signs in Estonian Sign Language

Directory of Open Access Journals (Sweden)

Liina Paales

2011-05-01

Full Text Available A place name sign is a linguistic-cultural marker that includes both memory and landscape. The author regards toponymic signs in Estonian Sign Language as representations of images held by the Estonian Deaf community: they reflect the geographical place, the period, the relationships of the Deaf community with hearing community, and the common and distinguishing features of the two cultures perceived by community's members. Name signs represent an element of signlore, which includes various types of creative linguistic play. There are stories hidden behind the place name signs that reveal the etymological origin of place name signs and reflect the community's memory. The purpose of this article is twofold. Firstly, it aims to introduce Estonian place name signs as Deaf signlore forms, analyse their structure and specify the main formation methods. Secondly, it interprets place-denoting signs in the light of understanding the foundations of Estonian Sign Language, Estonian Deaf education and education history, the traditions of local Deaf communities, and also of the cultural and local traditions of the dominant hearing communities. Both perspectives - linguistic and folkloristic - are represented in the current article.

A nonlocal strain gradient model for dynamic deformation of orthotropic viscoelastic graphene sheets under time harmonic thermal load

Science.gov (United States)

Radwan, Ahmed F.; Sobhy, Mohammed

2018-06-01

This work presents a nonlocal strain gradient theory for the dynamic deformation response of a single-layered graphene sheet (SLGS) on a viscoelastic foundation and subjected to a time harmonic thermal load for various boundary conditions. Material of graphene sheets is presumed to be orthotropic and viscoelastic. The viscoelastic foundation is modeled as Kelvin-Voigt's pattern. Based on the two-unknown plate theory, the motion equations are obtained from the dynamic version of the virtual work principle. The nonlocal strain gradient theory is established from Eringen nonlocal and strain gradient theories, therefore, it contains two material scale parameters, which are nonlocal parameter and gradient coefficient. These scale parameters have two different effects on the graphene sheets. The obtained deflection is compared with that predicted in the literature. Additional numerical examples are introduced to illustrate the influences of the two length scale coefficients and other parameters on the dynamic deformation of the viscoelastic graphene sheets.

Superconducting cavity material for the European XFEL

Science.gov (United States)

Singer, W.; Singer, X.; Brinkmann, A.; Iversen, J.; Matheisen, A.; Navitski, A.; Tamashevich, Y.; Michelato, P.; Monaco, L.

2015-08-01

Analysis of the strategy for superconducting cavity material procurement and quality management is done on the basis of the experience with the cavity production for the European x-ray free electron laser (EXFEL) facility. An adjustment of the material specification to EXFEL requirements, procurement of material, quality control (QC), documentation, and shipment to cavity producers have been worked out and carried out by DESY. A multistep process of qualification of the material suppliers included detailed material testing, single- and nine-cell cavity fabrication, and cryogenic radiofrequency tests. Production of about 25 000 semi-finished parts of high purity niobium and niobium-titanium alloy in a period of three years has been divided finally between companies Heraeus, Tokyo Denkai, Ningxia OTIC, and PLANSEE. Consideration of large-grain (LG) material as a possible option for the EXFEL has resulted in the production of one cryogenic module consisting of seven (out of eight) LG cavities. LG materials fulfilled the EXFEL requirements and showed even 25% to 30% higher unloaded quality factor. A possible shortage of the required quantity of LG material on the market led, however, to the choice of conventional fine-grain (FG) material. Eddy-current scanning (ECS) has been applied as an additional QC tool for the niobium sheets and contributed significantly to the material qualification and sorting. Two percent of the sheets have been rejected, which potentially could affect up to one-third of the cavities. The main imperfections and defects in the rejected sheets have been analyzed. Samples containing foreign material inclusions have been extracted from the sheets and electrochemically polished. Some inclusions remained even after 150 μm surface layer removal. Indications of foreign material inclusions have been found in the industrially fabricated and treated cavities and a deeper analysis of the defects has been performed.

Fabrication and properties of strip casting 4.5 wt% Si steel thin sheet

Energy Technology Data Exchange (ETDEWEB)

Zu, Guoqing, E-mail: gz854@uowmail.edu.au [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia); Zhang, Xiaoming [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Zhao, Jingwei [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia); Wang, Yuqian [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Yan, Yi [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia); Li, Chengang; Cao, Guangming [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Jiang, Zhengyi [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia)

2017-02-15

Three 4.5 wt% Si steel thin sheets with different thicknesses were efficiently fabricated by twin-roll strip casting, warm rolling and cold rolling followed by final annealing. A comprehensive investigation from the workability of the as-cast strip to the magnetic property of the produces was performed to illustrate the superiority of the new materials. The results show that the as-cast strip, which has a much lower Vickers hardness than that of the 6.5 wt% Si steel, is suitable for rolling processing. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies confirm that no ordering phase exists in the as-cast strip. The cold-rolled thin sheets exhibit good surface quality without edge cracks. Furthermore, all the three 4.5 wt% Si steel thin sheets possess relative strong <100>//ND texture and present high magnetic inductions and low iron losses after finial annealing. - Highlights: • 4.5 wt% Si as-cast sheet with excellent workability was produced by strip casting. • Three 4.5 wt% Si thin sheets were effectively fabricated by warm and cold rolling. • The microstructure and macro-texture of the thin sheets were elucidated. • High magnetic inductions and low iron losses were achieved simultaneously.

Cold Forming of Ni-Ti Shape Memory Alloy Sheet

Science.gov (United States)

Fann, Kaung-Jau; Su, Jhe-Yung

2018-03-01

Ni-Ti shape memory alloy has two specific properties, superelasiticity and shape memory effect, and thus is widely applied in diverse industries. To extend its further application, this study attempts to investigate the feasibility of cold forming its sheet blank especially under a bi-axial tensile stress state. Not only experiments but also a Finite Element Analysis (FEA) with DEFORM 2D was conducted in this study. The material data for FEA was accomplished by the tensile test. An Erichsen-like cupping test was performed as well to determine the process parameter for experiment setup. As a result of the study, the Ni-Ti shape memory alloy sheet has a low formability for cold forming and shows a relative large springback after releasing the forming load.

Characterizing Grain-Oriented Silicon Steel Sheet Using Automated High-Resolution Laue X-ray Diffraction

Science.gov (United States)

Lynch, Peter; Barnett, Matthew; Stevenson, Andrew; Hutchinson, Bevis

2017-11-01

Controlling texture in grain-oriented (GO) silicon steel sheet is critical for optimization of its magnetization performance. A new automated laboratory system, based on X-ray Laue diffraction, is introduced as a rapid method for large scale grain orientation mapping and texture measurement in these materials. Wide area grain orientation maps are demonstrated for both macroetched and coated GO steel sheets. The large secondary grains contain uniform lattice rotations, the origins of which are discussed.

Sucrose Treated Carbon Nanotube and Graphene Yarns and Sheets

Science.gov (United States)

Sauti, Godfrey (Inventor); Kim, Jae-Woo (Inventor); Siochi, Emilie J. (Inventor); Wise, Kristopher E. (Inventor)

2017-01-01

Consolidated carbon nanotube or graphene yarns and woven sheets are consolidated through the formation of a carbon binder formed from the dehydration of sucrose. The resulting materials, on a macro-scale are lightweight and of a high specific modulus and/or strength. Sucrose is relatively inexpensive and readily available, and the process is therefore cost-effective.

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

Static current-sheet models of quiescent prominences

Science.gov (United States)

Wu, F.; Low, B. C.

1986-12-01

A particular class of theoretical models idealize the prominence to be a discrete flat electric-current sheet suspended vertically in a potential magnetic field. The weight of the prominence is supported by the Lorentz force in the current sheet. These models can be extended to have curved electric-current sheets and to vary three-dimensionally. The equation for force balance is 1 over 4 pi (del times B) times Bdel p- p9 z=zero. Using Cartesian coordinates we take, for simplicity, a uniform gravity with constant acceleration g in the direction -z. If we are interested not in the detailed internal structure of the prominence, but in the global magnetic configuration around the prominence, we may take prominence plasma to be cold. Consideration is given to how such equilibrium states can be constructed. To simplify the mathematical problem, suppose there is no electric current in the atmosphere except for the discrete currents in the cold prominence sheet. Let us take the plane z =0 to be the base of the atmosphere and restrict our attention to the domain z greater than 0. The task we have is to solve for a magnetic field which is everywhere potential except on some free surface S, subject to suit able to boundary conditions. The surface S is determined by requiring that it possesses a discrete electric current density such that the Lorentz force on it is everywhere vertically upward to balance the weight of the material m(S). Since the magnetic field is potential in the external atmosphere, the latter is decoupled from the magnetic field and its plane parallel hydrostatic pressure and density can be prescribed.

Sign language perception research for improving automatic sign language recognition

NARCIS (Netherlands)

Ten Holt, G.A.; Arendsen, J.; De Ridder, H.; Van Doorn, A.J.; Reinders, M.J.T.; Hendriks, E.A.

2009-01-01

Current automatic sign language recognition (ASLR) seldom uses perceptual knowledge about the recognition of sign language. Using such knowledge can improve ASLR because it can give an indication which elements or phases of a sign are important for its meaning. Also, the current generation of

Flexible Engineering Structures from the Corrugated Metal Sheets - Comparison of Costs of Solutions used in the Road Building

Science.gov (United States)

Ołdakowska, E.

2017-11-01

The flexible structures from the corrugated metal sheets are used in particular in the road building, especially as passages for animals. Easy and quick assembly, as well as lower realization costs when compared to the traditional solutions increase interest in such structures. Availability and variety of systems allows for searching for solutions which are the best and optimal in the economical range. The article presents the comparison of costs of the basic materials used in various systems of flexible structures from the corrugated metal sheets. In order to determine the costs of the material solutions the data for two systems used in Poland (for construction of the upper passages for animals) since 2008 have been used. The cost estimation for the basic materials required for realization of 1 m2 of the flexible structure from the corrugated steel sheets have been prepared with use of prices obtained directly from the Polish contractors and manufacturers, as well as process included in the quarterly information (Sekocenbud). The difference of prices of materials available on the market allows the investor for selecting the structure depending on the needs and financial possibilities, as well as for achieving some savings. The savings in case of purchasing sheets of identical parameters (thickness, profile characteristics) are from approx. 4% to 8% per 1 m2 of sheet. The connectors in form of bolts M20 cl. 8.8 of various lengths are an expense from 3.00 PLN to 3.50 PLN. Those values may seem low, but taking into consideration amounts connected with construction of many square meters of structure they may become very important factor in the total investment costs.

46 CFR 232.4 - Balance sheet accounts.

Science.gov (United States)

2010-10-01

... 46 Shipping 8 2010-10-01 2010-10-01 false Balance sheet accounts. 232.4 Section 232.4 Shipping... ACTIVITIES UNIFORM FINANCIAL REPORTING REQUIREMENTS Balance Sheet § 232.4 Balance sheet accounts. (a.... (b) Purpose of balance sheet accounts. The balance sheet accounts are intended to disclose the...

Porous sheet-like and sphere-like nano-architectures of SnO2 nanoparticles via a solvent-thermal approach and their gas-sensing performances

International Nuclear Information System (INIS)

Jie Liu; Tang, Xin-Cun; Xiao, Yuan-Hua; Hai Jia,; Gong, Mei-Li; Huang, Fu-Qin

2013-01-01

Highlights: • Porous sheet-like and sphere-like nano-architectures of SnO 2 nanoparticles have been prepared. • A solvent-thermal approach without surfactant or polymer templates simply by changing the volume ratio of DMF to water. • The formation mechanism of nano-architectures is proposed in this article. • Porous sphere-like SnO 2 nano-architectures exhibit good sensitivity to the reduce vapors tested. • Sheet-like materials show better selectivity to ethanol. -- Abstract: Porous sheet-like and sphere-like nano-architectures of SnO 2 nanoparticles have been prepared via a solvent-thermal approach in the absence of any surfactant or polymer templates by simply changing the volume ratio of DMF to water. The nano-materials have been characterized by FESEM, XRD, IR, TEM and BET. A mechanism for the formation of nano-architectures is also proposed based on the assembly behaviors of DMF in water. The gas sensors constructed with porous sphere-like SnO 2 nano-architectures exhibit much higher sensitivity to the reduce vapors tested, compared to those from porous sheet-like SnO 2 materials, while the sheet-like materials show better selectivity to ethanol. The nano-architectures fabricated with the facile method are promising candidates for building chemical sensors with tunable performances

The strength research of the adhesive joints of sheet structures ...

African Journals Online (AJOL)

The research results of stress-strained condition of constructional sheet materials are given in the article. The strength dependence on type, configuration and sizes of adhesive joints is analyzed. The research of the strength dependence was made on the samples from bakelite plywood with the main types of adhesive joints ...

The influence of surface topography on the forming friction of automotive aluminum sheet

Energy Technology Data Exchange (ETDEWEB)

Kramer, Pamela Ann [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

1998-05-01

Interest in utilizing aluminum alloys in automobiles has increased in recent years as a result of the desire to lower automobile weight and, consequently, increase fuel economy. While aluminum alloy use in cast parts has increased, outer body panel applications are still being investigated. The industry is interested in improving the formability of these sheet alloys by a combination of alloy design and processing. A different avenue of improving the formability of these alloys may be through patterning of the sheet surface. Surface patterns hold the lubricant during the forming process, with a resulting decrease in the sheet-die surface contact. While it has been speculated that an optimum surface pattern would consist of discrete cavities, detailed investigation into the reduction of forming friction by utilizing discrete patterns is lacking. A series of discrete patterns were investigated to determine the dependence of the forming friction of automotive aluminum alloys on pattern lubricant carrying capacity and on material strength. Automotive aluminum alloys used in outer body panel applications were rolled on experimental rolls that had been prepared with a variety of discrete patterns. All patterns for each alloy were characterized before and after testing both optically and, to determine pattern lubricant capacity, using three dimensional laser profilometry. A draw bead simulation (DBS) friction tester was designed and fabricated to determine the forming friction of the patterned sheets. Tensile testing and frictionless DBS testing were performed to ascertain the material properties of each sheet. The most striking result of this work was the inversely linear dependence of forming friction on the lubricant carrying capacity of the discrete patterns.

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

Texture and structure of VT-19 alloy thin sheets and their welded joints

International Nuclear Information System (INIS)

Ehgiz, I.V.; Babarehko, A.A.; Khorev, M.A.

1986-01-01

The phase content and texture of VT-19 alloys in all zones of welded joints (weld, a heat affected zone a base metal) after different heat treatments and the effect of the latter on mechanical properties of the welded joint are studied. It is characteristic of a 2.5 mm sheet of the VT-19 alloy rolled in the β → α phase transformation temperature range the development of β-phase plane deformation textures with (001), (112), (111) orientations in the rolling plane that compose 56% of the β-phase material volume. In this case a texture of univariant phase transformation of the above β-phase components { 1120 } - { 1122 } - { 1124 }, as well as that of α-phase plane deformation } 1014 } - { 1015 } are formed in the α-phase. Hardening with subsequent ageing of the rolled sheet leads to increasing the fraction of textured material in the β-phase up to 95% with expanding the volume with the (111) orientation, but as a whole the β-phase texture type remains the same. The α-phase texture type corresponds to the univariant β → α phase transformation, the material having the α-phase texture accounts for 70%. In the weld zone the and axes with orientation spreading to 20 deg are the β-phase crystallization axes in the trans verse direction. The textured material accounts for ∼ 70%. The same texture is observed along the normal to the sheet plane. The α-phase texture after hardening and ageing corresponds to the univariant phase transformation of the above-mentionedβ-phase orientations, the material volume with the α-phase texture is ∼80%

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.

Investigation of sheet steel St 37.2 under mechanical impact

International Nuclear Information System (INIS)

Berg, H.P.; Brennecke, P.; Koester, R.; Friehmelt, V.

1990-01-01

Special waste originating, e.g. from chemical industry and radioactive wastes are emplaced in disposal mines. Slinger stowing is an approved technique to fill up residual voids in emplacement rooms. If it should be applied, possible mechanical loads on the integrity of sheet steel containers have to be considered. By theoretical calculations and by experiments under variation of different parameters using test specimen and backfill material from the Konrad mine using the container type V as an example it has been shown that sheet steel St 37.2 with a wall thickness of 3 mm will withstand mechanical impact imposed by backfill particles having a speed of 24 m/s. (orig.) [de

A System of Test Methods for Sheet Metal Forming Tribology

DEFF Research Database (Denmark)

Bay, Niels; Olsson, David Dam; Andreasen, Jan Lasson

2007-01-01

Sheet metal forming of tribologically difficult materials such as stainless steel, Al-alloys and Ti-alloys or forming in tribologically difficult operations like ironing, punching or deep drawing of thick plate requires often use of environmentally hazardous lubricants such as chlorinated paraffin...... oils in order to avoid galling. The present paper describes a systematic research in the development of new, environmentally harmless lubricants focusing on the lubricant testing aspects. A system of laboratory tests has been developed to study the lubricant performance under the very varied conditions...... appearing in different sheet forming operations such as stamping, deep drawing, ironing and punching. The laboratory tests have been especially designed to model the conditions in industrial production....

Single crystalline electronic structure and growth mechanism of aligned square graphene sheets

Directory of Open Access Journals (Sweden)

H. F. Yang

2018-03-01

Full Text Available Recently, commercially available copper foil has become an efficient and inexpensive catalytic substrate for scalable growth of large-area graphene films for fundamental research and applications. Interestingly, despite its hexagonal honeycomb lattice, graphene can be grown into large aligned square-shaped sheets on copper foils. Here, by applying angle-resolved photoemission spectroscopy with submicron spatial resolution (micro-ARPES to study the three-dimensional electronic structures of square graphene sheets grown on copper foils, we verified the high quality of individual square graphene sheets as well as their merged regions (with aligned orientation. Furthermore, by simultaneously measuring the graphene sheets and their substrate copper foil, we not only established the (001 copper surface structure but also discovered that the square graphene sheets’ sides align with the ⟨110⟩ copper direction, suggesting an important role of copper substrate in the growth of square graphene sheets—which will help the development of effective methods to synthesize high-quality large-size regularly shaped graphene sheets for future applications. This work also demonstrates the effectiveness of micro-ARPES in exploring low-dimensional materials down to atomic thickness and sub-micron lateral size (e.g., besides graphene, it can also be applied to transition metal dichalcogenides and various van der Waals heterostructures

Magnetic properties and recrystallization texture of phosphorus-added non-oriented electrical steel sheets

International Nuclear Information System (INIS)

Tanaka, I.; Yashiki, H.

2006-01-01

The effect of phosphorus on magnetic properties and recrystallization texture has been investigated in non-oriented electrical steel sheets to develop low core loss and high permeability core materials. Specimens with different phosphorus contents were cold-rolled to various thicknesses, i.e. with various cold-rolling reductions, and annealed for recrystallization and grain growth. Although magnetic induction of the steel with low phosphorus content dramatically dropped with reducing thickness, i.e. with increasing in cold-rolling reduction, that of the steel with high phosphorus content only slightly decreased. The most effective way to reduce core loss was to reduce thickness of electrical steel sheets. Therefore, phosphorus-added thin gauge non-oriented electrical steel sheets have achieved low core loss and high permeability. The typical magnetic properties of phosphorus-added non-oriented electrical steel sheets 0.27mm in sheet thickness were 16.6W/kg in W 10/400 and 1.73T in B 50 . These excellent magnetic properties were due to the recrystallization texture control. {111} component in recrystallization texture was suppressed by the phosphorus segregation at initial grain boundaries. Accordingly, phosphorus would greatly contribute to the improvement of magnetic properties

Pearl necklace sign in diabetic macular edema: Evaluation and significance

Directory of Open Access Journals (Sweden)

Kshirasagar Ajay

2016-01-01

Full Text Available Purpose: (1 The purpose of this study was to describe significance and prevalence of the newly reported pearl necklace spectral domain optical coherence tomography (SDOCT sign, in diabetic macular edema (DMO, (2 to track the course of this sign over a period of at least 10 months. Materials and Methods: The pearl necklace SDOCT sign refers to hyperreflective dots in a contiguous ring around the inner wall of cystoid spaces in the retina, recently described for the first time in 21 eyes with chronic exudative maculopathy. A retrospective analysis was performed of SDOCT images of all patients presenting to the DMO referral clinic of a tertiary eye care center, over a period of 24 months. Images of patients displaying this sign were sequentially analyzed for at least 10 months to track the course of the sign. Results: Thirty-five eyes of 267 patients (13.1% were found to display the pearl necklace sign. Twenty-eight eyes responded to intravitreal ranibizumab treatment with resolution of edema. In 21 eyes, the dots coalesced to form a clump, visible in the infrared fundus photograph as hard exudates; in seven eyes, dots disappeared without leaving visible exudates. In three eyes, the sign was seen in subfoveal cystoid spaces, with subsequent development of hard exudates, and drop in visual acuity of 20 letters or more. Conclusion: Pearl necklace SDOCT sign is not infrequent in DMO. This sign is a precursor to hard exudates in the majority of cases. If this sign is seen subfoveally, drop in visual acuity can be expected, despite treatment.

Study on antioxidant experiment on forged steel tube sheet and tube hole for steam generator

International Nuclear Information System (INIS)

Zong Hai; Wang Detai; Ding Yang

2012-01-01

Antioxidant experiment on forged steel tube sheet and tube hole for steam generator was studied and the influence of different simulated heat treatments on the antioxidant performance of tube sheet and tube hole was made. The influence of different antioxidant methods on the size of tube hole was drawn. Furthermore, the change of size and weight of 18MnD5 forged steel tube sheet on the condition of different simulated heat treatments was also studied. The analytical results have proved reference information for the use of 18MnD5 material and for key processes of processing tube hole and wearing and expanding U-style tube. (authors)

Chernobyl: before and after. Information sheet No. 1

Energy Technology Data Exchange (ETDEWEB)

Devine, J [comp.

1986-01-01

Complied in June 1986 the information sheet lists title, authors, and journal details and gives brief details of all relevant published articles. Part 1 concerns material relevant before the accident in April 1986 - the construction, design and safety of the Chernobyl RBMK nuclear power station (20 references). Part 2 lists articles published after the accident concerning the impact of the disaster on safety in the nuclear power industry (23 references).

Porous fluoropolymeric fibrous sheet and method of manufacture

Energy Technology Data Exchange (ETDEWEB)

Martin, G.E.; Cockshott, I.D.; McAloon, K.T.

1978-11-28

A method of preparing a porous sheet product comprises the step of introducing a spinning liquid comprising an organic fiber forming polymeric material into an electric field whereby fibers are drawn from the liquid to an electrode and collecting the fibers so produced upon the electrode. PTFE and other fluorinated polymer mats produced by the electrostatic process are useful as electrolytic cell diaphragms, battery separators, etc. 4 figures, 3 tables

'Felson Signs' revisited

International Nuclear Information System (INIS)

George, Phiji P.; Irodi, Aparna; Keshava, Shyamkumar N.; Lamont, Anthony C.

2014-01-01

In this article we revisit, with the help of images, those classic signs in chest radiography described by Dr Benjamin Felson himself, or other illustrious radiologists of his time, cited and discussed in 'Chest Roentgenology'. We briefly describe the causes of the signs, their utility and the differential diagnosis to be considered when each sign is seen. Wherever possible, we use CT images to illustrate the basis of some of these classic radiographic signs.

Chemical and radiation stability of a proprietary cesium ion exchange material manufactured from WWL membrane and SuperLig reg-sign 644

International Nuclear Information System (INIS)

Brown, G.N.; Carson, K.J.; DesChane, J.R.; Elovich, R.J.; Berry, P.K.

1996-09-01

Pretreatment of nuclear process wastes for ion exchange removal of Cs and other radionuclides is one way to minimize amount of high-level radioactive waste at Hanford. This study evaluated Cs-selective SuperLig reg-sign 644 (IBC Advanced Technologies, American Fork UT) entrapped in a proprietary WWL web membrane (3M) for chemical/radiation stability in simulated caustic neutralized current acid waste (NCAW), 0.5M HNO 3 , water, and air. After exposure up to 2.0E+09 rad, the material was evaluated for Cs uptake in 5M sodium NCAW simulants with varying Cs contents. Radiolytic stability appears to be sufficient for ion exchange pretreatment of radioactive Cs: essentially no decrease in Cs selectivity or loading (Kd) was observed during 60 Cs gamma irradiation in water or 0.5M HNO 3 up to 1.0E+09 rad. Cs Kd decreased by a factor of 2 after 2.0E+09 rad exposure. Cs Kd did not change during irradiation in 5M NCAW or ambient air up to 1.0E+08 rad, but decreased by more than an order of magnitude between 1.0E+08 and 2.0E+09 rad (not typical of process conditions). Chemical stability under caustic conditions is lower than in air or under neutral/acidic conditions. Results indicate that this material is less stable in caustic solution irrespective of radiation exposure. Samples of the membrane retained their physical form throughout the entire experiment and were only slightly brittle after exposure to 2.0E+09 rad. (The material evaluated was a finely ground (400 mesh) particulate engineered to form a polymeric fiber (WWL), not the macroscopic form of SuperLig reg-sign 644 resin (20 to 50 mesh).)

A cylindrical current sheet over the South solar pole observed by Ulysses

Science.gov (United States)

Khabarova, Olga; Kislov, Roman; Malova, Helmi; Obridko, Vladimir

2016-04-01

We provide the first evidence for the existence of a quasi-stable cylindrical current sheet over the South solar pole as observed by Ulysses in 2006, near the solar minimum, when it reached maximal heliolatitude of 79.7 degrees at 2.4 AU. It took place inside a fast speed stream from the coronal hole, and the tube was presumably crossed rather far from the center within two degrees of heliolatitude and ~10 degrees of heliolongitude. During the spacecraft passage throughout the structure, the solar wind velocity was approximately twice as little, the solar wind density was 20 times lower than the surrounded plasma values, but the temperature was twice as large in the point closest to the pole. The interplanetary magnetic field (IMF) strongly decreased due to sharp variations in the IMF radial component (RTN) that changed its sign twice, but other components did not show changes out of usual stochastic behavior. Both the behavior of the IMF, rotation of the plasma flow direction and other features indicate the occurrence of cylindrical current sheet. We discuss its solar origin and present modeling that can explain the observations.

Prediction of Ductile Failure in the Stretch-Forming of AA2024 Sheets

International Nuclear Information System (INIS)

Vallellano, C.; Guzman, C.; Garcia-Lomas, F. J.

2007-01-01

A number of ductile failure criteria are nowadays being used to predict the formability of aluminium alloy sheets. Generally speaking, integral criteria (e.g. those proposed by Cockcroft and Latham, Brozzo et al., Oyane et al Chaouadi et al., etc.) have been probed to work well when the principal strains are of opposite sign, i.e. in the left side of the Forming Limit Diagram (FLD). However, when tensile biaxial strains are present, as occurs in stretch-forming practice, their predictions are usually very poor and even non-conservatives. As an alternative, local criteria, such as the classical Tresca's and Bressan and Williams' criteria, have demonstrated a good capability to predict the failure in some automotive aluminum alloys under stretching. The present work analyses experimentally and numerically the failure in AA2024-T3 sheets subjected to biaxial stretching. A series of out-of-plane stretching tests have been simulated using ABAQUS. The experimental and the numerical FLD for different failure criteria are compared. The influence on the failure of the hydrostatic pressure and the normal stress to the fracture plane is also discussed

Human corneal endothelial cell transplantation using nanocomposite gel sheet in bullous keratopathy.

Science.gov (United States)

Parikumar, Periasamy; Haraguchi, Kazutoshi; Senthilkumar, Rajappa; Abraham, Samuel Jk

2018-01-01

Transplantation of in vitro expanded human corneal endothelial precursors (HCEP) cells using a nanocomposite (D25-NC) gel sheet as supporting material in bovine's cornea has been earlier reported. Herein we report the transplantation of HCEP cells derived from a cadaver donor cornea to three patients using the NC gel sheet. In three patients with bullous keratopathy, one after cataract surgery, one after trauma and another in the corneal graft, earlier performed for congenital corneal dystrophy, not amenable to medical management HCEP cells isolated from a human cadaver donor cornea in vitro expanded using a thermoreversible gelation polymer (TGP) for 26 days were divided into three equal portions and 1.6 × 10 5 HCEP cells were injected on to the endothelium of the affected eye in each patient using the D25-NC gel sheet as a supporting material. The sheets were removed after three days. The bullae in the cornea disappeared by the 3 rd -11 th post-operative day in all the three patients. Visual acuity improved from Perception of light (PL)+/Projection of rays (PR)+ to Hand movements (HM)+ in one of the patients by post-operative day 3 which was maintained at 18 months follow-up. At 18 months follow-up, in another patient the visual acuity had improved from HM+ to 6/60 while in the third patient, visual acuity remained HM+ as it was prior to HCEP transplantation. There were no adverse effects during the follow-up in any of the patients.

sign-by-sign'' correlation

International Nuclear Information System (INIS)

Schmidt, Sabine; Lepori, Domenico; Meuwly, Jean-Yves; Duvoisin, Bertrand; Meuli, Reto; Schnyder, Pierre; Denys, Alban; Michetti, Pierre; Felley, Christian; Melle, Guy van

2003-01-01

Our objective was a prospective comparison of MR enteroclysis (MRE) with multidetector spiral-CT enteroclysis (MSCTE). Fifty patients with various suspected small bowel diseases were investigated by MSCTE and MRE. The MSCTE was performed using slices of 2.5 mm, immediately followed by MRE, obtaining T1- and T2-weighted sequences, including gadolinium-enhanced acquisition with fat saturation. Three radiologists independently evaluated MSCTE and MRE searching for 12 pathological signs. Interobserver agreement was calculated. Sensitivities and specificities resulted from comparison with pathological results (n=29) and patient's clinical evolution (n=21). Most pathological signs, such as bowel wall thickening (BWT), bowel wall enhancement (BWE) and lymphadenopathy (ADP), showed better interobserver agreement on MSCTE than on MRE (BWT: 0.65 vs 0.48; BWE: 0.51 vs 0.37; ADP: 0.52 vs 0.15). Sensitivity of MSCTE was higher than that of MRE in detecting BWT (88.9 vs 60%), BWE (78.6 vs 55.5%) and ADP (63.8 vs 14.3%). Wilcoxon signed-rank test revealed significantly better sensitivity of MSCTE than that of MRE for each observer (p=0.028, p=0.046, p=0.028, respectively). Taking the given study design into account, MSCTE provides better sensitivity in detecting lesions of the small bowel than MRE, with higher interobserver agreement. (orig.)

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 ...

Thematic sheets on the nuclear energy

International Nuclear Information System (INIS)

Tevissen, E.; Galle, Ch.; L'Hostis, V.; Millard, A.; Moulin, Ch.; Mauchien, P.; Vitart, X.; Rivalier, P.; Diop, Ch.; Boullis, B.; Feron, D.; Santarini, G.; Lieven, Th.; Laffont, G.; Cachon, L.; Moulin, C.

2004-01-01

This document presents eleven description sheets of researches realized in the CEA laboratories. The following topics are concerned: the diffusion of tritiated water, iodine 125 and chlorine 36 in the Meuse/Haute-Marne rocks of the underground laboratory of Bure; effect of the granulates nature on the thermal and hydro mechanics behavior of concrete at high temperature (60-450 C); first validation of a damage model for reinforced concrete affected by the corrosion of its reinforcements; analysis of pollutants traces; centrifuge extractors of the high activity laboratory; the advanced partitioning; the disadvantages of the Monte-Carlo method in the radiation protection domain; the Purex process; materials damage by enzymes; the acoustic emission applied for the materials corrosion; the helium circuits technology for the gas cooled reactors; high level speciation. (A.L.B.)

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.

Parameter optimization and stretch enhancement of AISI 316 sheet using rapid prototyping technique

Science.gov (United States)

Moayedfar, M.; Rani, A. M.; Hanaei, H.; Ahmad, A.; Tale, A.

2017-10-01

Incremental sheet forming is a flexible manufacturing process which uses the indenter point-to-point force to shape the sheet metal workpiece into manufactured parts in batch production series. However, the problem sometimes arising from this process is the low plastic point in the stress-strain diagram of the material which leads the low stretching amount before ultra-tensile strain point. Hence, a set of experiments is designed to find the optimum forming parameters in this process for optimum sheet thickness distribution while both sides of the sheet are considered for the surface quality improvement. A five-axis high-speed CNC milling machine is employed to deliver the proper motion based on the programming system while the clamping system for holding the sheet metal was a blank mould. Finally, an electron microscope and roughness machine are utilized to evaluate the surface structure of final parts, illustrate any defect may cause during the forming process and examine the roughness of the final part surface accordingly. The best interaction between parameters is obtained with the optimum values which lead the maximum sheet thickness distribution of 4.211e-01 logarithmic elongation when the depth was 24mm with respect to the design. This study demonstrates that this rapid forming method offers an alternative solution for surface quality improvement of 65% avoiding the low probability of cracks and low probability of crystal structure changes.

The development of PVC-laminated steel sheet by an electron beam curing method

International Nuclear Information System (INIS)

Masuhara, Ken-ichi; Koshiishi, Kenji; Tomosue, Takao; Mori, Koji; Honma, Nobuyuki

1988-01-01

Polyvinyl chloride (PVC) film-laminated steel sheets are used for household electric appliances and building materials. Those are produced usually by pressing a PVC film onto a steel sheet imediately after a themosetting adhesive has been applied to the sheet and curing. However, a major problem of this method is that the appearance of the PVC films such as gloss and embossment changes during pressing due to the heat that is required for causing bonding, therefore, the development of an adhesive which can be cured at lower temperature is necessary. Nisshin Steel Co., Ltd. has developed PVC film-laminated steel sheets for which electron beam (EB) curable adhesives are used to overcome this problem. The advantage of these adhesives is that they can be quickly cured at room temperature. The production procedure of PVC-laminated steel sheets by EB curing is outlined. But this method has encountered two problems: poor adhesion between substrates and adhesive due to the residual stress, and the deterioration of the PVC films due to EB irradiation. EB curable adhesives are mainly composed of acrylic ester oligomers and monomers, and thier adhesion was improved by organic pretreatment. On the other hand, EB-proof PVC films were developed. The general properties of PVC-laminated steel sheets produced by EB curing are reported. (K.I.)

Process Simulation of Aluminium Sheet Metal Deep Drawing at Elevated Temperatures

International Nuclear Information System (INIS)

Winklhofer, Johannes; Trattnig, Gernot; Lind, Christoph; Sommitsch, Christof; Feuerhuber, Hannes

2010-01-01

Lightweight design is essential for an economic and environmentally friendly vehicle. Aluminium sheet metal is well known for its ability to improve the strength to weight ratio of lightweight structures. One disadvantage of aluminium is that it is less formable than steel. Therefore complex part geometries can only be realized by expensive multi-step production processes. One method for overcoming this disadvantage is deep drawing at elevated temperatures. In this way the formability of aluminium sheet metal can be improved significantly, and the number of necessary production steps can thereby be reduced. This paper introduces deep drawing of aluminium sheet metal at elevated temperatures, a corresponding simulation method, a characteristic process and its optimization. The temperature and strain rate dependent material properties of a 5xxx series alloy and their modelling are discussed. A three dimensional thermomechanically coupled finite element deep drawing simulation model and its validation are presented. Based on the validated simulation model an optimised process strategy regarding formability, time and cost is introduced.

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.

Nickel–cobalt layered double hydroxide ultrathin nanoflakes decorated on graphene sheets with a 3D nanonetwork structure as supercapacitive materials

International Nuclear Information System (INIS)

Yan, Tao; Li, Ruiyi; Li, Zaijun

2014-01-01

Graphical abstract: The microwave heating reflux approach was developed for the fabrication of nickel–cobalt layered double hydroxide ultrathin nanoflakes decorated on graphene sheets, in which ammonia and ethanol were used as the precipitator and medium for the synthesis. The obtained composite shows a 3D flowerclusters morphology with nanonetwork structure and largely enhanced supercapacitive performance. - Highlights: • The paper reported the microwave synthesis of nickel–cobalt layered double hydroxide/graphene composite. • The novel synthesis method is rapid, green, efficient and can be well used to the mass production. • The as-synthesized composite offers a 3D flowerclusters morphology with nanonetwork structure. • The composite offers excellent supercapacitive performance. • This study provides a promising route to design and synthesis of advanced graphene-based materials with the superiorities of time-saving and cost-effective characteristics. - Abstract: The study reported a novel microwave heating reflux method for the fabrication of nickel–cobalt layered double hydroxide ultrathin nanoflakes decorated on graphene sheets (GS/NiCo-LDH). Ammonia and ethanol were employed as precipitant and reaction medium for the synthesis, respectively. The resulting GS/NiCo-LDH offers a 3D flowerclusters morphology with nanonetwork structure. Due to the greatly enhanced rate of electron transfer and mass transport, the GS/NiCo-LDH electrode exhibits excellent supercapacitive performances. The maximum specific capacitance was found to be 1980.7 F g −1 at the current density of 1 A g −1 . The specific capacitance can remain 1274.7 F g −1 at the current density of 15 A g −1 and it has an increase of about 2.9% after 1500 cycles. Moreover, the study also provides a promising approach for the design and synthesis of metallic double hydroxides/graphene hybrid materials with time-saving and cost-effective characteristics, which can be potentially applied

Method of using sacrificial materials for fabricating internal cavities in laminated dielectric structures

Science.gov (United States)

Peterson, Kenneth A [Albuquerque, NM

2009-02-24

A method of using sacrificial materials for fabricating internal cavities and channels in laminated dielectric structures, which can be used as dielectric substrates and package mounts for microelectronic and microfluidic devices. A sacrificial mandrel is placed in-between two or more sheets of a deformable dielectric material (e.g., unfired LTCC glass/ceramic dielectric), wherein the sacrificial mandrel is not inserted into a cutout made in any of the sheets. The stack of sheets is laminated together, which deforms the sheet or sheets around the sacrificial mandrel. After lamination, the mandrel is removed, (e.g., during LTCC burnout), thereby creating a hollow internal cavity in the monolithic ceramic structure.

Utilization of a Biodegradable Mulch Sheet Produced from Poly(Lactic Acid/Ecoflex®/Modified Starch in Mandarin Orange Groves

Directory of Open Access Journals (Sweden)

Yasukatsu Maeda

2009-08-01

Full Text Available We have developed a mulch sheet made by inflation molding of PLA, Ecoflex® and modified starch, which all have different biodegradabilities. A field test of use as an agricultural mulch sheet for mandarin oranges was carried out over two years. The mechanical properties of the mulch sheet were weakened with time during the field test, but the quality of the mandarin oranges increased, a result of the controlled degradation of the sheet. The most degradable modified starch degraded first, allowing control of the moisture on the soil. Accelerator mass spectroscopy was used for evaluation of the biomass carbon ratio. The biomass carbon ratio decreased by degradation of the biobased materials, PLA and modified starch in the mulch sheet.

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.

Embedded Aligned Carbon Nanotube Sheets for Strain and Damage sensing in Composite Structures

Science.gov (United States)

Aly, Karim Aly Abdelomoaty Elsayed

The world demand for fiber reinforced composite materials has been steadily increasing because of the widespread adoption of this class of material in many markets. The automotive, aerospace, marine and energy sectors account for a large percentage of this grow. Outstanding fatigue performance, high specific stiffness and strength, and low density are among the most important properties that fiber reinforced polymer composites offer. Furthermore, their properties can be tailored to meet the specific needs of the final applications. However, this class of material is composed of multiple layers of inhomogeneous and anisotropic constituents, i.e. fibers and matrix. Therefore, this laminated nature make the composite material prone to intrinsic damage including interfacial debonding and delamination and their strength and failure are dependent on the fiber architecture and direction of the applied stresses. Consequently, it is of prime importance to monitor the health of these structures. New and improved methods for early detection of damage and structural health monitoring of composite materials may allow for enhanced reliability, lifetime and performance while minimizing maintenance time during a composite part's service life. Over the last few decades different non-destructive methods and materials have been investigated for use as strain sensors. Since the discovery of carbon nanotubes (CNTs), they have attracted much research interest due to their superior electrical, thermal and mechanical properties as well as their high aspect ratio. In this context, CNTs have been used in the recent years to enable sensing capabilities. In this dissertation, the usage of CNTs for performing strain and damage sensing in composites is evaluated. This was enabled by embedding aligned sheets of two millimeters long, interconnected CNTs into laminated structures that were then subjected to different forms of mechanical loading. The localization of the CNT sheets inside the host

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

Thin lead sheets in the decorative features in Pavia Charterhouse.

Science.gov (United States)

Colombo, Chiara; Realini, Marco; Sansonetti, Antonio; Rampazzi, Laura; Casadio, Francesca

2006-01-01

The facade of the church of the Pavia Charterhouse, built at the end of the 15th century, shows outstanding decorative features made of different stone materials, such as marbles, breccias and sandstones. Magnificent ornamental elements are made of thin lead sheets, and some marble slabs are inlaid with them. Metal elements are shaped in complex geometric and phytomorphic design, to form a Greek fret in black contrasting with the white Carrara marble. Lead pins were fixed to the back of the thin lead sheets with the aim of attaching the metal elements to the marble; in so doing the pins and the lead sheets constitute a single piece of metal. In some areas, lead elements have been lost, and they have been substituted with a black plaster, matching the colour of the metal. To the authors' knowledge, this kind of decorative technique is rare, and confirms the refinement of Renaissance Lombard architecture. This work reports on the results of an extensive survey of the white, orange and yellowish layers, which are present on the external surface of the lead. The thin lead sheets have been characterized and their state of conservation has been studied with the aid of Optical Microscopy, SEM-EDS, FTIR and Raman analyses. Lead sulphate, lead carbonates and oxides have been identified as decay products.

Animal-eyeball vs. road-sign retroreflectors.

Science.gov (United States)

Greene, Nathaniel R; Filko, Brian J

2010-01-01

The retroreflective characteristics of ex-vitro cow and deer eyeballs were compared to those of man-made materials used in road signs and bicycle-style reflectors. Reflected intensities were measured using a goniometer that consists of a green He-Ne laser as the light source, and a photomultiplier tube as the detector. It was found that the best quality road-sign reflector, made from a 200-micron-scale, close-packed array of corner cubes, is approximately six times more efficient than a cow eyeball at returning light in the direction of the incoming beam. Less expensive man-made retroreflectors, utilizing 35-micron glass beads (as in mailbox decals) or millimeter-scale arrays of corner cubes (bicycle-style reflectors) are, however, less efficient than the cow eye. The high quality of animal eyeball optics is evidenced by their extremely tight angular spread (full width half maximum congruent with 1 degrees) of retroreflected intensity about the incident path. Moreover, as the reflector itself is rotated relative to the incident beam, the eyeballs preserve their efficiency of retroreflection better than the man-made materials. Interference-diffraction patterns were observed in the retroreflected beams from the small-scale corner cubes, but were not observed in eyeball retroreflection.

Signs of the Times: Signage in the Library.

Science.gov (United States)

Johnson, Carolyn

1993-01-01

Discusses the use of signs in libraries and lists 12 steps to create successful signage. Highlights include consistency, location, color, size, lettering, types of material, user needs, signage policy, planning, in-house fabrication versus vendors, and evaluation, A selected bibliography of 24 sources of information on library signage is included.…

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.

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

Science.gov (United States)

Sagapuram, Dinakar

basal slip exhibits ductile tensile-type fracture. A two-fold increase in ductility is also observed for the LSEM sheet under uniaxial tensile testing without significant changes in the strength. Among texture and microstructure (grain size), texture is shown to be more critical for Mg sheet formability. However, in conjunction with a favorable texture, fine recrystallized microstructure provides for additional enhancement of strain-hardening capacity and formability. In-situ imaging of material flow during uniaxial tensile testing revealed new, interesting flow localization phenomena and fracture behavior. It is shown that the deformation behavior of Mg sheet is highly texture dependent, and also radically different from that of conventional ductile metals both in terms of necking and fracture. The implications of these observations for the LDH test results and formability of Mg sheet, in general, are briefly discussed.

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

Biomass derived nitrogen-doped hierarchical porous carbon sheets for supercapacitors with high performance.

Science.gov (United States)

Wang, Cunjing; Wu, Dapeng; Wang, Hongju; Gao, Zhiyong; Xu, Fang; Jiang, Kai

2018-08-01

A facile potassium chloride salt-locking technique combined with hydrothermal treatment on precursors was explored to prepare nitrogen-doped hierarchical porous carbon sheets in air from biomass. Benefiting from the effective synthesis strategy, the as-obtained carbon possesses a unique nitrogen-doped thin carbon sheet structure with abundant hierarchical pores and large specific surface areas of 1459 m 2  g -1 . The doped nitrogen in carbon framework has a positive effect on the electrochemical properties of the electrode material, the thin carbon sheet structure benefits for fast ion transfer, the abundant meso-pores provide convenient channels for rapid charge transportation, large specific surface area and lots of micro-pores guarantee sufficient ion-storage sites. Therefore, applied for supercapacitors, the carbon electrode material exhibits an outstanding specific capacitance of 451 F g -1 at 0.5 A g -1 in a three-electrode system. Moreover, the assembled symmetric supercapacitor based on two identical carbon electrodes also displays high specific capacitance of 309 F g -1 at 0.5 A g -1 , excellent rate capacity and remarkable cycling stability with 99.3% of the initial capacitance retention after 10,000 cycles at 5 A -1 . The synthesis strategy avoids expensive inert gas protection and the use of corrosive KOH and toxic ZnCl 2 activated reagents, representing a promising green route to design advanced carbon electrode materials from biomass for high-capacity supercapacitors. Copyright © 2018. Published by Elsevier Inc.

Sign Inference for Dynamic Signed Networks via Dictionary Learning

Directory of Open Access Journals (Sweden)

Yi Cen

2013-01-01

Full Text Available Mobile online social network (mOSN is a burgeoning research area. However, most existing works referring to mOSNs deal with static network structures and simply encode whether relationships among entities exist or not. In contrast, relationships in signed mOSNs can be positive or negative and may be changed with time and locations. Applying certain global characteristics of social balance, in this paper, we aim to infer the unknown relationships in dynamic signed mOSNs and formulate this sign inference problem as a low-rank matrix estimation problem. Specifically, motivated by the Singular Value Thresholding (SVT algorithm, a compact dictionary is selected from the observed dataset. Based on this compact dictionary, the relationships in the dynamic signed mOSNs are estimated via solving the formulated problem. Furthermore, the estimation accuracy is improved by employing a dictionary self-updating mechanism.

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...

Awareness of Deaf Sign Language and Gang Signs.

Science.gov (United States)

Smith, Cynthia; Morgan, Robert L.

There have been increasing incidents of innocent people who use American Sign Language (ASL) or another form of sign language being victimized by gang violence due to misinterpretation of ASL hand formations. ASL is familiar to learners with a variety of disabilities, particularly those in the deaf community. The problem is that gang members have…

Utilizing Waste Thermocol Sheets and Rusted Iron Wires to Fabricate Carbon-Fe3O4 Nanocomposite Based Supercapacitors: Turning Wastes into Value-Added Materials.

Science.gov (United States)

Vadiyar, Madagonda M; Liu, Xudong; Ye, Zhibin

2018-05-14

In the present work, we demonstrate the synthesis of porous activated carbon (specific surface area, 1,883 m2 g-1), Fe3O4 nanoparticles, and carbon-Fe3O4 nanocomposites using local waste thermocol sheets and rusted iron wires. The resulting carbon, Fe3O4 nanoparticles, and carbon-Fe3O4 composites are used as electrode materials for supercapacitor application. In particular, C-Fe3O4 composite electrodes exhibit a high specific capacitance of 1,375 F g-1 at 1 A g-1 and longer cyclic stability with 98 % of capacitance retention over 10,000 cycles. Subsequently, asymmetric supercapacitor, i. e., C-Fe3O4//Ni(OH)2/CNT device exhibits a high energy density of 91.1 Wh kg-1 and a remarkable cyclic stability, showing 98% of capacitance retention over 10,000 cycles. Thus, this work has important implications not only for the fabrication of low-cost electrodes for high-performance supercapacitors but also for the recycling of waste thermocol sheets and rust iron wires for value-added reuse. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interaction of β-sheet folds with a gold surface.

Directory of Open Access Journals (Sweden)

Martin Hoefling

Full Text Available The adsorption of proteins on inorganic surfaces is of fundamental biological importance. Further, biomedical and nanotechnological applications increasingly use interfaces between inorganic material and polypeptides. Yet, the underlying adsorption mechanism of polypeptides on surfaces is not well understood and experimentally difficult to analyze. Therefore, we investigate here the interactions of polypeptides with a gold(111 surface using computational molecular dynamics (MD simulations with a polarizable gold model in explicit water. Our focus in this paper is the investigation of the interaction of polypeptides with β-sheet folds. First, we concentrate on a β-sheet forming model peptide. Second, we investigate the interactions of two domains with high β-sheet content of the biologically important extracellular matrix protein fibronectin (FN. We find that adsorption occurs in a stepwise mechanism both for the model peptide and the protein. The positively charged amino acid Arg facilitates the initial contact formation between protein and gold surface. Our results suggest that an effective gold-binding surface patch is overall uncharged, but contains Arg for contact initiation. The polypeptides do not unfold on the gold surface within the simulation time. However, for the two FN domains, the relative domain-domain orientation changes. The observation of a very fast and strong adsorption indicates that in a biological matrix, no bare gold surfaces will be present. Hence, the bioactivity of gold surfaces (like bare gold nanoparticles will critically depend on the history of particle administration and the proteins present during initial contact between gold and biological material. Further, gold particles may act as seeds for protein aggregation. Structural re-organization and protein aggregation are potentially of immunological importance.

Study of Axes Rotation during Simple Shear Tests on Aluminum Sheets

International Nuclear Information System (INIS)

Duchene, L.; Diouf, B.; Lelotte, T.; Flores, P.; Habraken, A. M.; Bouvier, S.

2007-01-01

In order to model accurately the anisotropic material behavior during finite element simulations, a precise description of the material yield locus is required. Beside the shape (linked to the material model used), the size (related to the isotropic hardening) and the position (kinematic hardening) of the yield locus, its orientation is of particular interest when large rotations of the material are encountered during the simulations. This paper proposes three distinct methods for the determination of the material yield locus rotation: a method based on the Constant Symmetric Local Velocity Gradient (CSLVG), a corotational method and a method based on the Mandel spin. These methods are compared during simple shear tests of an aluminum sheet

Compression deformation behaviors of sheet metals at various clearances and side forces

Directory of Open Access Journals (Sweden)

Zhan Mei

2015-01-01

Full Text Available Modeling sheet metal forming operations requires understanding of plastic behaviors of sheet metals along non-proportional strain paths. The plastic behavior under reversed uniaxial loading is of particular interest because of its simplicity of interpretation and its application to material elements drawn over a die radius and underwent repeated bending. However, the attainable strain is limited by failures, such as buckling and in-plane deformation, dependent on clearances and side forces. In this study, a finite element (FE model was established for the compression process of sheet specimens, to probe the deformation behavior. The results show that: With the decrease of the clearance from a very large value to a very small value, four defects modes, including plastic t-buckling, micro-bending, w-buckling, and in-plane compression deformation will occur. With the increase of the side force from a very small value to a very large value, plastic t-buckling, w-buckling, uniform deformation, and in-plane compression will occur. The difference in deformation behaviors under these two parameters indicates that the successful compression process without failures for sheet specimens only can be carried out under a reasonable side force.

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...

Heated Hydro-Mechanical Deep Drawing of Magnesium Sheet Metal

Science.gov (United States)

Kurz, Gerrit

In order to reduce fuel consumption efforts have been made to decrease the weight of automobile constructions by increasing the use of lightweight materials. In this field of application magnesium alloys are important because of their low density. A promising alternative to large surfaced and thin die casting parts has been found in construction parts that are manufactured by sheet metal forming of magnesium. Magnesium alloys show a limited formability at room temperature. A considerable improvement of formability can be achieved by heating the material. Formability increases above a temperature of approximately T = 225 °C.

IMPACT OF STRAIN RATE ON MICROALLOYED STEEL SHEET BREAKING

Directory of Open Access Journals (Sweden)

Mária Mihaliková

2014-08-01

Full Text Available Strain rate is a significant external factor and its influence on material behavior in forming process is a function of its internal structure. The contribution is analysis of the impact of loading rate from 1.6 x 10-4 ms-1 to 24 ms-1 to changes in the fracture of steel sheet used for bodywork components in cars. Experiments were performed on samples taken from HC420LA grade strips produced by cold rolling and hot dip galvanizing. Material strength properties were compared based on measured values, and changes to fracture surface character were observed.

Formability Prediction Of Aluminum Sheet In Automotive Applications

International Nuclear Information System (INIS)

Leppin, Christian; Daniel, Dominique; Shahani, Ravi; Gese, Helmut; Dell, Harry

2007-01-01

In the following paper, a full mechanical characterization of the AA6016 T4 aluminum alloy car body sheet DR100 is presented. A comprehensive experimental program was performed to identify and model the orthotopic elasto-plastic deformation behavior of the material and its fracture characteristics including criteria for localized necking, ductile fracture and shear fracture. The commercial software package MF GenYld + CrachFEM in combination with the explicit finite element code Ls-Dyna is used to validate the quality of the material model with experiments, namely, prediction of the FLD, deep drawing with a cross-shaped punch and finally, analysis of a simplified hemming process using a solid discretization of the problem. The focus is on the correct prediction of the limits of the material in such processes

Recent progresses in application of functionalized graphene sheets

Institute of Scientific and Technical Information of China (English)

无

2010-01-01

Graphene,a rapidly rising star on the horizon of material science,has a unique two-dimensional nanostructure as well as exceptional mechanical and electronic properties.Despite its short history,graphene has exhibited great potential in various applications.In order to implement the potential applications,functionalization of graphene is necessary to obtain uniform dispersions for good processability.Two kinds are dominant for functionalization such as covalent and non-covalent methods.The former is based on the formation of covalent bonds,and the latter the interaction among molecules.In this review,we summarized briefly the recent progress of functionalized graphene sheets (FGs) in different fields,such as optoelectronic materials,sensors,energy storage materials,catalytic,reinforcing components and so on,and also prospected the development trend of FGs in the future.

Useful signs for identification of the central sulcus in MRI

International Nuclear Information System (INIS)

Carrasco, E.; Domitrovic, L.; Ypa, P.; Gandarillas Baldelomar, B.; Fuentes, F.; Arcos, A.

2011-01-01

Objective. To describe the frequency of appearance of the central sulcus localizing signs in magnetic resonance images (MRI). Material and method. The MRI of 60 adult patients (18-83 years) of both sexes (34 women / 26 men) with normal brains were studied. Axial T1 and T2 images were performed on a Phillips 1.5 tesla resonator. On the MRI we looked the following signs: union between the superior frontal sulcus and the precentral sulcus, sigmoidal hook, pars bracket, bifid post central sulcus, union between the intraparietal sulcus and the post central sulcus and, central sulcus reaching the midline. Mean frequencies were calculated. Results. The posterior part of the superior frontal sulcus joined the precentral sulcus in 95% of the cases. Sigmoidal hook sign was seen in 96.66% of the cases. Pars bracket sign was present in 95% of the observations. Bifid postcentral sulcus sign was seen in 65 % of cases. The postcentral gyrus was thinner than the precentral gyrus in 98.33% of the cases. Intraparietal sulcus joined with the postcentral gyrus in 88.33% of the cases. The central sulcus reached the midline in 86.66% of the observations. Conclusion. The signs described had a high frequency: they were found in 89.28% of the MRI studied. (authors)

Ultra-shallow junction (USJ) sheet resistance measurements with a non-penetrating four point probe

International Nuclear Information System (INIS)

Benjamin, M.C.; Hillard, R.J.; Borland, J.O.

2005-01-01

An accurate method to measure the four point probe (4PP) sheet resistance (R S ) of ultra shallow junction (USJ) Source-Drain Extension structures is described. The method utilizes Elastic Material probes (EM-probes) to form non-penetrating contacts to the silicon surface [R.J. Hillard, P.Y. Hung, William Chism, C. Win Ye, W.H. Howland, L.C. Tan, C.E. Kalnas, Characterization and Metrology for ULSI Technology, AIP Conference proceedings 683 (2003) 802.]. The probe design is kinematic and the force is controlled to ensure elastic deformation of the probe material. The probe material is such that large direct tunneling currents can flow through the native oxide thereby forming a low impedance contact. Sheet resistance measurements on USJ implanted P+/N structures with Secondary Ion Mass Spectroscopy (SIMS) junction depths less than 15 nm have been measured. The method is demonstrated on implanted USJ structures and found to be consistent with expectations

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.

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...

Formability of porous tantalum sheet-metal

International Nuclear Information System (INIS)

Nebosky, Paul S; Schmid, Steven R; Pasang, Timotius

2009-01-01

Over the past ten years, a novel cellular solid, Trabecular Metal T M , has been developed for use in the orthopaedics industry as an ingrowth scaffold. Manufactured using chemical vapour deposition (CVD) on top of a graphite foam substrate, this material has a regular matrix of interconnecting pores, high strength, and high porosity. Manufacturing difficulties encourage the application of bending, stamping and forming technologies to increase CVD reactor throughput and reduce material wastes. In this study, the bending and forming behaviour of Trabecular Metal T M was evaluated using a novel camera-based system for measuring surface strains, since the conventional approach of printing or etching gridded patterns was not feasible. A forming limit diagram was obtained using specially fabricated 1.65 mm thick sheets. A springback coefficient was measured and modeled using effective hexagonal cell arrangements.

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.

Automatic sign language recognition inspired by human sign perception

NARCIS (Netherlands)

Ten Holt, G.A.

2010-01-01

Automatic sign language recognition is a relatively new field of research (since ca. 1990). Its objectives are to automatically analyze sign language utterances. There are several issues within the research area that merit investigation: how to capture the utterances (cameras, magnetic sensors,

Inuit Sign Language: a contribution to sign language typology

NARCIS (Netherlands)

Schuit, J.; Baker, A.; Pfau, R.

2011-01-01

Sign language typology is a fairly new research field and typological classifications have yet to be established. For spoken languages, these classifications are generally based on typological parameters; it would thus be desirable to establish these for sign languages. In this paper, different

Investigation into Composites Property Effect on the Forming Limits of Multi-Layer Hybrid Sheets Using Hydroforming Technology

Science.gov (United States)

Liu, Shichen; Lang, Lihui; Guan, Shiwei; Alexandrov, Seigei; Zeng, Yipan

2018-04-01

Fiber-metal laminates (FMLs) such as Kevlar reinforced aluminum laminate (ARALL), Carbon reinforced aluminum laminate (CARALL), and Glass reinforced aluminum laminate (GLARE) offer great potential for weight reduction applications in automobile and aerospace construction. In order to investigate the feasibility for utilizing such materials in the form of laminates, sheet hydroforming technology are studied under the condition of uniform blank holder force for three-layered aluminum and aluminum-composite laminates using orthogonal carbon and Kevlar as well as glass fiber in the middle. The experimental results validate the finite element results and they exhibited that the forming limit of glass fiber in the middle is the highest among the studied materials, while carbon fiber material performs the worst. Furthermore, the crack modes are different for the three kinds of fiber materials investigated in the research. This study provides fundamental guidance for the selection of multi-layer sheet materials in the future manufacturing field.

Reduction of Pulmonary Air Leaks with a Combination of Polyglycolic Acid Sheet and Alginate Gel in Rats

Directory of Open Access Journals (Sweden)

Mari Matoba

2018-01-01

Full Text Available Postoperative air leaks remain a major cause of morbidity after lung resection. This study evaluated the effect of a combination of polyglycolic acid (PGA sheet and alginate gel on pulmonary air leaks in rats. Four pulmonary sealing materials were evaluated in lung injury: fibrin glue, combination of PGA sheet and fibrin glue, alginate gel, and combination of PGA sheet and alginate gel. With the airway pressure maintained at 20 cmH2O, a 2 mm deep puncture wound was created on the lung surface using a needle. Lowering the airway pressure to 5 cmH2O, each sealing material was applied. The lowest airway pressure that broke the seal was measured. The seal-breaking pressure in each experimental group was fibrin, 10.4±6.8 cmH2O; PGA + fibrin, 13.5±6.5 cmH2O; alginate gel, 10.3±4.9 cmH2O; and PGA + alginate, 35.8±11.9 cmH2O, respectively. The seal-breaking pressure was significantly greater in the PGA + alginate gel group than in the other groups (p<0.01. There were no significant differences among the other three groups. Alginate gel combined with a PGA sheet is a promising alternative to fibrin glue as a safe and low-cost material for air leak prevention in pulmonary surgery.

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.

Formation of sheeting joints in Yosemite National Park, California

Science.gov (United States)

Martel, S. J.

2009-04-01

The formation of sheeting joints (i.e., "exfoliation joints"), opening mode fractures subparallel to the Earth's surface, has been a classic unresolved problem in geology. Diverse new observations and analyses support the hypothesis that sheeting joints develop in response to a near-surface tension induced by compressive stresses parallel to a convex slope (hypothesis 1) rather than the conventional explanation that the joints form as a result of removal of overburden by erosion (hypothesis 2). The opening mode displacements across the joints together with the absence of mineral precipitates within the joints mean that sheeting joints open in response to a near-surface tension normal to the surface (N) rather than a pressurized fluid. An absolute tension must arise in the shallow subsurface if a plot of N as a function of depth normal to the surface (z) has a positive slope at the surface (z=0). The differential equations of static equilibrium require that this slope (derivative) equals k2 P22 + k3 P33 - ?g cosβ, where k2 and k3 are the principal curvatures of the surface, P22 and P33 are the respective surface-parallel normal stresses along the principal curvatures, ? is the material density, g is gravitational acceleration, and β is the slope. This derivative will be positive and sheeting joints can open if the surface-parallel stress in at least one direction is sufficiently compressive (negative) and the curvature in that direction is sufficiently convex (negative). Hypotheses 1 and 2 are being tested using geologic mapping and aerial LIDAR data from Yosemite National Park, California. The abundance of sheeting joints on convex ridges there, where erosion is a local minimum, coupled with their scarcity in the adjacent concave valleys, where erosion is a local maximum, is consistent with hypothesis 1 but inconsistent with hypothesis 2. At several sites with sheeting joints, measurements of the current topographic curvatures and the current surface

Model for Predicting Traffic Signs Functional Service Life – The Republic of Croatia Case Study

Directory of Open Access Journals (Sweden)

Dario Babić

2017-06-01

Full Text Available Traffic signs are the basic elements of communication between the relevant road authorities and road users. They manage, regulate, inform and warn road users to ensure their safe movement throughout transport networks. Traffic signs must be timely visible to all traffic participants in all weather and traffic conditions in order to fulfil their function, which means they must have satisfactory retroreflection properties. This paper presents a research of the deterioration of traffic signs retroreflection. The aim of this article is to develop models that will effectively enable predicting the retroreflection of traffic signs and thus optimize the maintenance activities and replacement of road signs to increase road safety. The research included measurements of retroreflection of retroreflective material Classes I and II (white, red and blue colour and Class III (red and yellow colour. Based on the collected data from the City of Zagreb (Republic of Croatia, the authors developed the models to estimate the functional service life of certain colours and materials used to make traffic signs. Considering that the average coefficient of determination for all the models is between 0.55-0.60, they present an effective tool in the traffic sign maintenance system.

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.

Finite element simulation of aluminum sheet warm forming using alflow hardening model

NARCIS (Netherlands)

Kurukuri, S.; van den Boogaard, Antonius H.; Huetink, Han

2007-01-01

In order to accurately model the plastic deformation of Aluminum sheet at elevated temperatures, a model is required that incorporate the temperature and strain rate dependency of the material. In this article, two physically based models are compared: Bergstr¨om and Alflow model. Although both

Incorporation of soft shaped hydrogel sheets into microfluidic systems using a simple adhesion masking process

Science.gov (United States)

Young, Dylan C.; Newsome, Isabel G.; Scrimgeour, Jan

2017-12-01

We report the use of simple adhesion masking in fabricating shaped, photo-polymerizable hydrogel sheets with very small elastic moduli on glass substrates. Direct ink masking of surface crosslinking groups allows for low cost hydrogel patterning that is compatible with materials where crosslinking is both photo- and chemically initiated. Mechanical removal of the unwanted polymerized material reveals the shaped hydrogel. The mechanical properties of the shaped hydrogels were characterized by exposure to well-defined shear flow inside the microfluidic device. We show that hydrogel sheets with elastic moduli down to 7.5 Pa can be shaped with millimeter feature sizes using this approach. The shaped hydrogels are suitable for applications such as the detection of shear flow, cell culture, and traction force microscopy.

The prediction of necking and failure in 3 D. Sheet forming analysis using damage variable

International Nuclear Information System (INIS)

Brunet, M.; Sabourin, F.; Mguil-Touchal, S.

1996-01-01

The modeling of necking occurrence in sheet metal forming is a real challenge for the engineer concerned with processing of new geometries and materials. As fracture in metal forming is mainly due to the development of ductile damage and to represent the failure of anisotropic sheet-metals, an extension of the Gurson-Tvergaard model is presented and implemented in the context of plane-stress for shell elements. A one dimensional problem is solved and compared with the exact solution of the literature. The paper closes with a numerical and experimental study of the necking of a square cup deep-drawing using the modified Gurson's model to described the constitutive behavior of the material. Finally, a numerical necking criterion is proposed. (orig.)

The prediction of necking and failure in 3 D. Sheet forming analysis using damage variable

Energy Technology Data Exchange (ETDEWEB)

Brunet, M. [INSA, Villeurbanne (France). Lab. de Mecanique des Solides; Sabourin, F. [INSA, Villeurbanne (France). Lab. de Mecanique des Solides; Mguil-Touchal, S. [INSA, Villeurbanne (France). Lab. de Mecanique des Solides

1996-10-01

The modeling of necking occurrence in sheet metal forming is a real challenge for the engineer concerned with processing of new geometries and materials. As fracture in metal forming is mainly due to the development of ductile damage and to represent the failure of anisotropic sheet-metals, an extension of the Gurson-Tvergaard model is presented and implemented in the context of plane-stress for shell elements. A one dimensional problem is solved and compared with the exact solution of the literature. The paper closes with a numerical and experimental study of the necking of a square cup deep-drawing using the modified Gurson`s model to described the constitutive behavior of the material. Finally, a numerical necking criterion is proposed. (orig.).

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

Basilar artery occlusion: Prognostic signs of severity on computed tomography

Energy Technology Data Exchange (ETDEWEB)

Poletti, Pierre-Alexandre, E-mail: pierre-alexandre.poletti@hcuge.ch [Service of Radiology, University Hospital of Geneva (Switzerland); Pereira, Vitor Mendes [Service of Neuroradiology, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211 Geneva (Switzerland); Department of Medical Imaging, University of Toronto (Canada); Department of Surgery, University of Toronto (Canada); Lovblad, Karl-Olof [Service of Neuroradiology, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211 Geneva (Switzerland); Canel, Lucie [Service of Radiology, University Hospital of Geneva (Switzerland); Sztajzel, Roman [Service of Neurology, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211 Geneva (Switzerland); Becker, Minerva [Service of Radiology, University Hospital of Geneva (Switzerland); Perneger, Thomas [Division of Clinical Epidemiology, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211 Geneva (Switzerland); Platon, Alexandra [Service of Radiology, University Hospital of Geneva (Switzerland)

2015-07-15

Highlights: • The main CT signs associated with basilar artery occlusion were analyzed. • CT sign of acute ischemic lesion is significantly associated with a bad outcome. • The site of the basilar artery occlusion is not associated to the patients’ outcome. - Abstract: Purpose: To determine the computed tomography (CT) signs that are predictive of the clinical outcome of basilar artery occlusion (BAO). Materials and methods: The study population consisted in 37 patients (14 women, 23 men, mean age: 63 years), admitted with onset of neurological deficit, starting 1–72 h prior to admission, who were diagnosed with BAO on the basis of a CT examination with intravenous contrast agent. The following signs were collected on CT scans performed on admission: clot density on noncontrast images, clot length, and clot location, as well as the presence of acute ischemic lesions. The results were compared against the modified Rankin Scale (mRS) score of patients at 3 months, favorable clinical outcome being defined as a mRS score ≤3. Results: The clinical outcome was favorable in 13 (35%) of the 37 patients and unfavorable in 24 (65%). Signs of acute ischemia were visible in 13 of the 24 patients with unfavorable outcome but in none of the 13 patients with favorable outcome (p < 0.001). None of the other CT signs analyzed were significantly correlated with clinical prognosis. Conclusion: Of all the CT signs analyzed, only the presence of signs of acute ischemia on the admission CT of patients with BAO was associated with poor prognosis.

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.

Toward the Ideal Signing Avatar

Directory of Open Access Journals (Sweden)

Nicoletta Adamo-Villani

2016-06-01

Full Text Available The paper discusses ongoing research on the effects of a signing avatar's modeling/rendering features on the perception of sign language animation. It reports a recent study that aimed to determine whether a character's visual style has an effect on how signing animated characters are perceived by viewers. The stimuli of the study were two polygonal characters presenting two different visual styles: stylized and realistic. Each character signed four sentences. Forty-seven participants with experience in American Sign Language (ASL viewed the animated signing clips in random order via web survey. They (1 identified the signed sentences (if recognizable, (2 rated their legibility, and (3 rated the appeal of the signing avatar. Findings show that while character's visual style does not have an effect on subjects' perceived legibility of the signs and sign recognition, it has an effect on subjects' interest in the character. The stylized signing avatar was perceived as more appealing than the realistic one.

Significance of satellite sign and spot sign in predicting hematoma expansion in spontaneous intracerebral hemorrhage.

Science.gov (United States)

Yu, Zhiyuan; Zheng, Jun; Ali, Hasan; Guo, Rui; Li, Mou; Wang, Xiaoze; Ma, Lu; Li, Hao; You, Chao

2017-11-01

Hematoma expansion is related to poor outcome in spontaneous intracerebral hemorrhage (ICH). Recently, a non-enhanced computed tomography (CT) based finding, termed the 'satellite sign', was reported to be a novel predictor for poor outcome in spontaneous ICH. However, it is still unclear whether the presence of the satellite sign is related to hematoma expansion. Initial computed tomography angiography (CTA) was conducted within 6h after ictus. Satellite sign on non-enhanced CT and spot sign on CTA were detected by two independent reviewers. The sensitivity and specificity of both satellite sign and spot sign were calculated. Receiver-operator analysis was conducted to evaluate their predictive accuracy for hematoma expansion. This study included 153 patients. Satellite sign was detected in 58 (37.91%) patients and spot sign was detected in 38 (24.84%) patients. Among 37 patients with hematoma expansion, 22 (59.46%) had satellite sign and 23 (62.16%) had spot sign. The sensitivity and specificity of satellite sign for prediction of hematoma expansion were 59.46% and 68.97%, respectively. The sensitivity and specificity of spot sign were 62.16% and 87.07%, respectively. The area under the curve (AUC) of satellite sign was 0.642 and the AUC of spot sign was 0.746. (P=0.157) CONCLUSION: Our results suggest that the satellite sign is an independent predictor for hematoma expansion in spontaneous ICH. Although spot sign has the higher predictive accuracy, satellite sign is still an acceptable predictor for hematoma expansion when CTA is unavailable. Copyright © 2017 Elsevier B.V. All rights reserved.

Computational triadic algebras of signs

Energy Technology Data Exchange (ETDEWEB)

Zadrozny, W. [T.J. Watson Research Center, Yorktown Heights, NY (United States)

1996-12-31

We present a finite model of Peirce`s ten classes of signs. We briefly describe Peirce`s taxonomy of signs; we prove that any finite collection of signs can be extended to a finite algebra of signs in which all interpretants are themselves being interpreted; and we argue that Peirce`s ten classes of signs can be defined using constraints on algebras of signs. The paper opens the possibility of defining multimodal cognitive agents using Peirce`s classes of signs, and is a first step towards building a computational logic of signs based on Peirce`s taxonomies.

Anisotropic carrier mobility in single- and bi-layer C3N sheets

Science.gov (United States)

Wang, Xueyan; Li, Qingfang; Wang, Haifeng; Gao, Yan; Hou, Juan; Shao, Jianxin

2018-05-01

Based on the density functional theory combined with the Boltzmann transport equation with relaxation time approximation, we investigate the electronic structure and predict the carrier mobility of single- and bi-layer newly fabricated 2D carbon nitrides C3N. Although C3N sheets possess graphene-like planar hexagonal structure, the calculated carrier mobility is remarkably anisotropic, which is found mainly induced by the anisotropic effective masses and deformation potential constants. Importantly, we find that both the electron and hole mobilities are considerable high, for example, the hole mobility along the armchair direction of single-layer C3N sheets can arrive as high as 1.08 ×104 cm2 V-1 s-1, greatly larger than that of C2N-h2D and many other typical 2D materials. Owing to the high and anisotropic carrier mobility and appropriate band gap, single- and bi-layer semiconducting C3N sheets may have great potential applications in high performance electronic and optoelectronic devices.

Laser cutting of laminated sheet material: a modeling exercise

NARCIS (Netherlands)

de Graaf, R.F.; Meijer, J.

1997-01-01

Laser cutting has been investigated for a number of aluminum-synthetic laminates, newly developed materials for the aeronautic and automotive industry. The materials consist of alternating aluminum and synthetic layers. It is shown that these materials can be cut at rates comparable to those of

Ultrasonic measurement of through-thickness stress gradients in textured sheet metals

International Nuclear Information System (INIS)

Man Chising; Li Jianbo; Fan Xingyan; Lu Weiyang

2000-01-01

The objective of this investigation is to explore the possibility of using the dispersion of high-frequency Rayleigh waves for the evaluation of through-thickness stress gradients at the surface of metal sheets. We consider an orthorhombic sheet of cubic metal with through-thickness inhomogeneities in stress and texture, and adopt a coordinate system under which the rolling (RD), transverse (TD), and normal direction (ND) of the sheet are taken as the 1-, 2-, and 3-direction, respectively. We restrict our attention to the special case where only the stress components T 11 (x 3 ) and T 22 (x 3 ) in the sheet are nonzero, and consider only Rayleigh waves of sufficiently high frequency for which the sheet can be taken as the half-space x 3 ≥0. For Rayleigh waves of two different frequencies (with wave numbers k 1 and k k 2 respectively) propagating on the same wave path along either RD or TD, we appeal to an analysis of J. Li and Man to obtain a high-frequency asymptotic formula which gives the relative change in time-of-flight Δt/t 0 as (1/k 1 -1/k 2 ) times a linear combination of the derivatives T 11 ' (0), T 22 ' (0), W 4m0 ' (0)(m=0,2,4) and W 6m0 (0)(m=0,2,4,6) at the surface are ascertained and the material constants in the acoustoelastic consitutive equation of this polycrystal are known. An experiment was performed on an AA7075-T651 aluminum alloy beam, in which Δt/t 0 was measured for various values of T 11 (0) and T 11 ' (0) produced by beam bending (with (T 22 ≡0). The relevant texture coefficients of the beam were measured by X-ray diffraction. To obtain specific predictions from the aforementioned symptotic formula, we replace the material constants of the sample by their counterparts predicted for polycrystalline (pure) aluminum by the Man-Paroni model. The predictions and Δt/t 0 are then compared with the experimental results

Hydrogen passivation of silicon sheet solar cells

International Nuclear Information System (INIS)

Tsuo, Y.S.; Milstein, J.B.

1984-01-01

Significant improvements in the efficiencies of dendritic web and edge-supported-pulling silicon sheet solar cells have been obtained after hydrogen ion beam passivation for a period of ten minutes or less. We have studied the effects of the hydrogen ion beam treatment with respect to silicon material damage, silicon sputter rate, introduction of impurities, and changes in reflectance. The silicon sputter rate for constant ion beam flux of 0.60 +- 0.05 mA/cm 2 exhibits a maximum at approximately 1400-eV ion beam energy

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.

Nanomesh phononic structures for low thermal conductivity and thermoelectric energy conversion materials

Science.gov (United States)

Yu, Jen-Kan; Mitrovic, Slobodan; Heath, James R.

2016-08-16

A nanomesh phononic structure includes: a sheet including a first material, the sheet having a plurality of phononic-sized features spaced apart at a phononic pitch, the phononic pitch being smaller than or equal to twice a maximum phonon mean free path of the first material and the phononic size being smaller than or equal to the maximum phonon mean free path of the first material.

Keyhole shapes during laser welding of thin metal sheets

International Nuclear Information System (INIS)

Aalderink, B J; Lange, D F de; Aarts, R G K M; Meijer, J

2007-01-01

Camera observations of the full penetration keyhole laser welding process show that the keyhole shape is elongated under certain welding conditions. Under these unfavourable circumstances, the welding process is susceptible to holes in the weld bead. Existing models of the pressure balance at the keyhole wall cannot explain this keyhole elongation. In this paper a new model is presented, accounting for the doubly curved shape of the keyhole wall. In this model, the surface tension pressure has one term that tends to close the keyhole and another term that tries to open it. Model calculations show that when the keyhole diameter is of the same order as the sheet thickness, the latter part can become dominant, causing the keyhole to elongate. Experiments on thin aluminium (AA5182) and mild steel (DC04) sheets verify these model calculations. As the keyhole radius depends on the radius of the focused laser spot, it was found for both materials that the ratio of the spot radius and the sheet thickness must be above a critical value to prevent keyhole elongation. These critical radii are 0.25 for AA5182 and 0.4 for DC04, respectively. Furthermore, differences in appearance of the weld bead between the circular and the elongated keyhole welds could be explained by this model

Space-DRUMS trade mark sign experimental development using parabolic reduced gravity flights

International Nuclear Information System (INIS)

Guigne, J.Y.; Millan, D.; Davidson, R.

2000-01-01

Space-DRUMS trade mark sign is a microgravity containerless-processing facility that uses acoustic beams to position large diameter liquid or solid samples within a gas-filled chamber. Its capacity to control the position of large diameter (6 cm) low density solid materials was successfully demonstrated on NASA's DC-9 parabolic aircraft in July 1996; two subsequent flights occurred in 1998 using the KC-135 and A-300 aircraft to further refine the technology used in the system. The working environment for the Space-DRUMS trade mark sign facility is the Space Shuttle/Space Station where long duration microgravity experimentation can take place. Since the reduced gravity environment of an A-300 or a KC-135 parabolic flight is much harsher than that of the Space Shuttle in terms of residual acceleration magnitudes experienced by the samples to be held in position; this more extreme environment allows for most Space-DRUMS trade mark sign technical payload functionality tests to be conducted. In addition to flight hardware shakedowns, parabolic flights continue to be extensively used to study and evaluate the behavior of candidate-advanced materials proposed for ISS Space-DRUMS trade mark sign campaigns. The first samples to be processed in 2001 involve combustion synthesis (also known as SHS - Self-propagating High Temperature Synthesis) of large glass-ceramic and of porous ceramic spheres. Upmassing Space-DRUMS trade mark sign for the International Space Station is scheduled for early 2001

Gesture, sign, and language: The coming of age of sign language and gesture studies.

Science.gov (United States)

Goldin-Meadow, Susan; Brentari, Diane

2017-01-01

How does sign language compare with gesture, on the one hand, and spoken language on the other? Sign was once viewed as nothing more than a system of pictorial gestures without linguistic structure. More recently, researchers have argued that sign is no different from spoken language, with all of the same linguistic structures. The pendulum is currently swinging back toward the view that sign is gestural, or at least has gestural components. The goal of this review is to elucidate the relationships among sign language, gesture, and spoken language. We do so by taking a close look not only at how sign has been studied over the past 50 years, but also at how the spontaneous gestures that accompany speech have been studied. We conclude that signers gesture just as speakers do. Both produce imagistic gestures along with more categorical signs or words. Because at present it is difficult to tell where sign stops and gesture begins, we suggest that sign should not be compared with speech alone but should be compared with speech-plus-gesture. Although it might be easier (and, in some cases, preferable) to blur the distinction between sign and gesture, we argue that distinguishing between sign (or speech) and gesture is essential to predict certain types of learning and allows us to understand the conditions under which gesture takes on properties of sign, and speech takes on properties of gesture. We end by calling for new technology that may help us better calibrate the borders between sign and gesture.

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

SIGNS The sandwich sign

African Journals Online (AJOL)

The sandwich sign is demonstrated on cross-sectional imaging, commonly on CT or ultrasound. It refers to homogeneous soft- tissue masses representing mesenteric lymphadenopathy as the two halves of a sandwich bun, encasing the mesenteric fat and tubular mesenteric vessels that constitute the 'sandwich filling' (Figs ...

Radiative heat transfer in 2D Dirac materials

International Nuclear Information System (INIS)

Rodriguez-López, Pablo; Tse, Wang-Kong; Dalvit, Diego A R

2015-01-01

We compute the radiative heat transfer between two sheets of 2D Dirac materials, including topological Chern insulators and graphene, within the framework of the local approximation for the optical response of these materials. In this approximation, which neglects spatial dispersion, we derive both numerically and analytically the short-distance asymptotic of the near-field heat transfer in these systems, and show that it scales as the inverse of the distance between the two sheets. Finally, we discuss the limitations to the validity of this scaling law imposed by spatial dispersion in 2D Dirac materials. (paper)

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.

Studies in Cup Drawing Behavior of Polymer Laminated Sheet Metal

Science.gov (United States)

Elnagmi, M.; Jain, M.; Bruhis, M.; Nielsen, K.

2011-08-01

Axisymmetric deep drawing behavior of a polymer laminated sheet metal (PLSM) is investigated using an axisymmetric cup drawing test. PLSMs are of interest as a replacement for painted finishes for automotive applications as they have the potential to achieve good quality long lasting and aesthetically appealing surfaces on stamped parts. However, there is limited understanding of PLSMs in automotive deep drawing situations to produce complex 3-D parts. The tests are carried out using well-controlled, laboratory-based, dual-action, servo-hydraulic forming presses under blank-holder force and punch displacement control conditions. An optical strain mapping system is used to measure the surface strains (and to construct 3D strain maps) from the film side of the deformed samples for a range of forming conditions. Deep drawing characteristics such as punch load versus punch displacement traces, strain distribution along the cup profile, flange wrinkling and fracture characteristics are experimentally assessed for stainless steel-plastic film laminated sheet materials. Also the effect of lamination pressure on wrinkling and delamination is investigated for a decorative pressure sensitive adhesive film affixed to the stainless steel sheet.

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.

Signed Language Working Memory Capacity of Signed Language Interpreters and Deaf Signers

Science.gov (United States)

Wang, Jihong; Napier, Jemina

2013-01-01

This study investigated the effects of hearing status and age of signed language acquisition on signed language working memory capacity. Professional Auslan (Australian sign language)/English interpreters (hearing native signers and hearing nonnative signers) and deaf Auslan signers (deaf native signers and deaf nonnative signers) completed an…

Information structure in Russian Sign Language and Sign Language of the Netherlands

NARCIS (Netherlands)

Kimmelman, V.

2014-01-01

This dissertation explores Information Structure in two sign languages: Sign Language of the Netherlands and Russian Sign Language. Based on corpus data and elicitation tasks we show how topic and focus are expressed in these languages. In particular, we show that topics can be marked syntactically

Warning Signs of Bullying

Science.gov (United States)

... of Aggressive Behavior Print Share Warning Signs for Bullying There are many warning signs that may indicate ... Get help right away . Signs a Child is Bullying Others Kids may be bullying others if they: ...

Preliminary Investigation of Impact on Multiple-Sheet Structures and an Evaluation of the Meteoroid Hazard to Space Vehicles

Science.gov (United States)

Nysmith, C. Robert; Summers, James L.

1961-01-01

Small pyrex glass spheres, representative of stoney meteoroids, were fired into 2024-T3 aluminum alclad multiple-sheet structures at velocities to 11,000 feet per second to evaluate the effectiveness of multisheet hull construction as a means of increasing the resistance of a spacecraft to meteoroid penetrations. The results of these tests indicate that increasing the number of sheets in a structure while keeping the total sheet thickness constant and increasing the spacing between sheets both tend to increase the penetration resistance of a structure of constant weight per unit area. In addition, filling the space between the sheets with a light filler material was found to substantially increase structure penetration resistance with a small increase in weight. An evaluation of the meteoroid hazard to space vehicles is presented in the form of an illustrative-example for two specific lunar mission vehicles, a single-sheet, monocoque hull vehicle and a glass-wool filled, double-sheet hull vehicle. The evaluation is presented in terms of the "best" and the "worst" conditions that might be expected as determined from astronomical and satellite measurements, high-speed impact data, and hypothesized meteoroid structures and compositions. It was observed that the vehicle flight time without penetration can be increased significantly by use of multiple-sheet rather than single-sheet hull construction with no increase in hull weight. Nevertheless, it is evident that a meteoroid hazard exists, even for the vehicle with the selected multiple-sheet hull.

Selectively reflective transparent sheets

Science.gov (United States)

Waché, Rémi; Florescu, Marian; Sweeney, Stephen J.; Clowes, Steven K.

2015-08-01

We investigate the possibility to selectively reflect certain wavelengths while maintaining the optical properties on other spectral ranges. This is of particular interest for transparent materials, which for specific applications may require high reflectivity at pre-determined frequencies. Although there exist currently techniques such as coatings to produce selective reflection, this work focuses on new approaches for mass production of polyethylene sheets which incorporate either additives or surface patterning for selective reflection between 8 to 13 μ m. Typical additives used to produce a greenhouse effect in plastics include particles such as clays, silica or hydroxide materials. However, the absorption of thermal radiation is less efficient than the decrease of emissivity as it can be compared with the inclusion of Lambertian materials. Photonic band gap engineering by the periodic structuring of metamaterials is known in nature for producing the vivid bright colors in certain organisms via strong wavelength-selective reflection. Research to artificially engineer such structures has mainly focused on wavelengths in the visible and near infrared. However few studies to date have been carried out to investigate the properties of metastructures in the mid infrared range even though the patterning of microstructure is easier to achieve. We present preliminary results on the diffuse reflectivity using FDTD simulations and analyze the technical feasibility of these approaches.

Topical safety analysis report for the transportation of the NUHOMS{reg_sign} dry shielded canister. Volume 2

Energy Technology Data Exchange (ETDEWEB)

None

1993-08-01

A thermal analyses for the 10CFR71 normal conditions of . transport and hypothetical accident conditions is presented for the conceptual NUHOMS{reg_sign} Transportation Cask and NUHOMS{reg_sign}-24P DSC system. The purpose of the thermal analyses presented herein is to demonstrate that the conceptual NUHOMS{reg_sign} Transportation Cask with the NUHOMS{reg_sign}-24P DSC provides suitable heat dissipation to maintain the heat removal capacity of the loaded NUHOMS{reg_sign} Transportation Cask. The thermal analyses results show that the maximum temperatures and pressures of the NUHOMS{reg_sign} Transportation Cask and the NUHOMS{reg_sign}-24P DSC are within their allowable material temperature and pressure limits.

Formability behavior studies on CP-Al sheets processed through the helical tool path of incremental forming process

Science.gov (United States)

Markanday, H.; Nagarajan, D.

2018-02-01

Incremental sheet forming (ISF) is a novel die-less sheet metal forming process, which can produce components directly from the CAD geometry using a CNC milling machine at less production time and cost. The formability of the sheet material used is greatly affected by the process parameters involved and tool path adopted, and the present study is aimed to investigate the influence of different process parameter values using the helical tool path strategy on the formability of a commercial pure Al and to achieve maximum formability in the material. ISF experiments for producing an 80 mm diameter axisymmetric dome were carried out on 2 mm thickness commercially pure Al sheets for different tool speeds and feed rates in a CNC milling machine with a 10 mm hemispherical forming tool. The obtained parts were analyzed for springback, amount of thinning and maximum forming depth. The results showed that when the tool speed was increased by keeping the feed rate constant, the forming depth and thinning were also increased. On contrary, when the feed rate was increased by keeping the tool speed constant, the forming depth and thinning were decreased. Springback was found to be higher when the feed rate was increased rather than the tool speed was increased.

Dried blood spots on carboxymethyl cellulose sheets: Rapid sample preparation based on dissolution and precipitation

DEFF Research Database (Denmark)

Skoglund Ask, Kristine; Pedersen-Bjergaard, Stig; Gjelstad, Astrid

2016-01-01

This short communication describes the use of carboxymethyl cellulose sheets as sampling material for dried blood spots. Whole blood, spiked with quetiapine, a hydrophobic and basic small molecule drug substance, was spotted on the sheet and subsequently dried. The dried spot was then almost...... completely dissolved in acidified aqueous solution. It was shown that the dissolved polymer, together with major blood components can easily be precipitated and removed with acetonitrile. The presented sampling on a water-soluble biopolymer derivative followed by precipitation resulted in a simple protocol...

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)

The Danish Sign Language Dictionary

DEFF Research Database (Denmark)

Kristoffersen, Jette Hedegaard; Troelsgård, Thomas

2010-01-01

The entries of the The Danish Sign Language Dictionary have four sections:  Entry header: In this section the sign headword is shown as a photo and a gloss. The first occurring location and handshape of the sign are shown as icons.  Video window: By default the base form of the sign headword...... forms of the sign (only for classifier entries). In addition to this, frequent co-occurrences with the sign are shown in this section. The signs in the The Danish Sign Language Dictionary can be looked up through:  Handshape: Particular handshapes for the active and the passive hand can be specified...... to find signs that are not themselves lemmas in the dictionary, but appear in example sentences.  Topic: Topics can be chosen as search criteria from a list of 70 topics....

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 ...

Plastic behaviour of zircoloy-4 sheets in function of the temperature

International Nuclear Information System (INIS)

Ordonez, S.; Marxsen, A.; Pochettino, A.; Vedoya, P.

1988-01-01

In order to the knowledge of plastic deformation mechanisms in Zry-4 thin sheets at high temperature and the effects that the interaction sample-oxidizing atmosphere induces on these mechanisms, a systematic study of the mechanical behaviour of the material in the temperature range 400 ' 0 C and under different oxidations contitions is present. (author) [pt

Stadis{reg_sign} 450 in Merox-sweetened jet fuels

Energy Technology Data Exchange (ETDEWEB)

Henry, C.P. [DuPont, Deepwater, NJ (United States)

1995-05-01

Stadis{reg_sign} 450 has been used in aviation fuels since 1983, and in many cases is the additive of choice due to conductivity retention of treated fuels during distribution, and other characteristics. In the past several years, manufacture of Shell ASA-3 (the other aviation-approved static dissipator additive) has been discontinued; current stores are being drawn down and for some refiners conversion from ASA-3 to Stadis{reg_sign} 450 is underway. In fuels sweetened by hydrogen-treating, Stadis{reg_sign} 450 performs very well and there are few reported difficulties. Chemically sweetened fuels sometimes contain trace materials not removed by the sweetening process. When treated with Stadis{reg_sign} 450 some of these fuels have exhibited two behaviors which are being addressed: in one case, the formation of a precipitate which disarmed coalescers; in several other cases, reduced conductivity response and loss of conductivity during storage coupled with unusually large effects on the microseparatometer water separation properties. In late 1992, a Coordinating Research Council (CRC) Panel on Coalescer Deactivation was formed to address these problems. The results of DuPont and CRC efforts are discussed, along with actions taken and underway to eliminate these problems.

Mechanics in Composite Materials and Process

International Nuclear Information System (INIS)

Lee, Dae Gil

1993-03-01

This book includes introduction of composite materials, stress, in-plane stiffness of laminates strain rate, ply stress, failure criterion and bending, composite materials micromechanics, composite plates and micromechanics of composite materials. It also deals with process of composite materials such as autoclave vacuum bag degassing process, connection of composite materials, filament winding process, resin transfer molding, sheet molding compound and compression molding.

Sign Language and Language Acquisition in Man and Ape. New Dimensions in Comparative Pedolinguistics.

Science.gov (United States)

Peng, Fred C. C., Ed.

A collection of research materials on sign language and primatology is presented here. The essays attempt to show that: sign language is a legitimate language that can be learned not only by humans but by nonhuman primates as well, and nonhuman primates have the capability to acquire a human language using a different mode. The following…

Modelling the formation of sheeting joints with FRACOD2D (FRActure propagation CODe)

International Nuclear Information System (INIS)

Lanaro, Flavio; Amemiya, Kiyoshi; Yamada, Atsuo

2008-01-01

This contribution shows an application of the newly developed gravity acceleration function in the BEM-DDM code FRACOD 2D . The influence of the model geometry, material parameters and boundary stresses on the initiation and propagation of sheeting joints due to rebound by removal of the overburden is studied. The models seem to capture the pattern of sheeting joints and the depth of their occurrence. The influence of the sheeting joints on the stress distributions in the rock mass also seem to be realistic and in agreement with field observations. The results indicate that the stresses measured in-situ at several sites in crystalline rock might exhibit the same features as the numerical results by FRACOD 2D . For example, the horizontal stress is found to be rather high at the surface of the models as it was observed in Forsmark, Sweden. Moreover, stresses where sheeting joints are developing are so severe to justify damage and fracturing of the intact rock observed in terms of fracture frequency and laboratory sample damage close to the surface at the Shobasama and MIU Construction Site, Mizunami, Japan. (author)

Up-scaling perovskite solar cell manufacturing from sheet-to-sheet to roll-to-roll: challenges and solutions

Science.gov (United States)

Di Giacomo, Francesco; Galagan, Yulia; Shanmugam, Santhosh; Gorter, Harrie; van den Bruele, Fieke; Kirchner, Gerwin; de Vries, Ike; Fledderus, Henri; Lifka, Herbert; Veenstra, Sjoerd; Aernouts, Tom; Groen, Pim; Andrissen, Ronn

2017-08-01

Organometallic halide perovskite solar cells (PSCs) are extremely promising novel materials for thin-film photovoltaics, exhibiting efficiencies over 22% on glass and over 17% on foil 1, 2 . First, a sheet-to-sheet (S2S) production of PSCs and modules on 152x152 mm2 substrates was established, using a combination of sputtering, e-beam evaporation, slot die coating and thermal evaporation (average PCE of 14.6 +/- 1.3 % over 64 devices, more than 10% initial PCE on modules). Later the steps towards a roll-to-roll production will be investigated, starting from the optimization of the stack to make it compatible with a faster production at low temperature. A water based SnOx nanoparticles dispersion was used as solution processable ETL, and the deposition process was scaled-up from spin coating to R2R slot die coating on a 300 mm wide roll of PET/ITO. R2R production is often carried out in ambient atmosphere and involve the use of large volumes of materials, thus a first point is the development of a green solvent and precursor system for the perovskite layer to prevent the emission of toxic compound in the environment. The first results on device fabrication are encouraging, which allow partial R2R manufacturing of flexible PSC (R2R coating of SnOx and perovskite, S2S for Spiro-OMeTAD and gold) with stabilized PCE of 12.6%, a remarkable value for these novel devices. This result can be considered an important milestone towards the production of efficient, low cost, lightweight, flexible PSC on large area.

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.

The Phonetics of Head and Body Movement in the Realization of American Sign Language Signs.

Science.gov (United States)

Tyrone, Martha E; Mauk, Claude E

2016-01-01

Because the primary articulators for sign languages are the hands, sign phonology and phonetics have focused mainly on them and treated other articulators as passive targets. However, there is abundant research on the role of nonmanual articulators in sign language grammar and prosody. The current study examines how hand and head/body movements are coordinated to realize phonetic targets. Kinematic data were collected from 5 deaf American Sign Language (ASL) signers to allow the analysis of movements of the hands, head and body during signing. In particular, we examine how the chin, forehead and torso move during the production of ASL signs at those three phonological locations. Our findings suggest that for signs with a lexical movement toward the head, the forehead and chin move to facilitate convergence with the hand. By comparison, the torso does not move to facilitate convergence with the hand for signs located at the torso. These results imply that the nonmanual articulators serve a phonetic as well as a grammatical or prosodic role in sign languages. Future models of sign phonetics and phonology should take into consideration the movements of the nonmanual articulators in the realization of signs. © 2016 S. Karger AG, Basel.

The measurement of magnetic properties of electrical sheet steel - survey on methods and situation of standards

CERN Document Server

Sievert, J

2000-01-01

A brief review of the different requirements for magnetic measurement techniques for material research, modelling of material properties and grading of the electrical sheet steel for trade purposes is presented. In relation to the main application of laminated electrical steel, this paper deals with AC measurement techniques. Two standard methods, Epstein frame and Single Sheet Tester (SST), producing different results, are used in parallel. This dilemma was analysed in detail. The study leads to a possible solution of the problem, i.e. the possibility of converting the results of one of the two methods into the results of the other in order to satisfy the users of the Epstein method and, at the same time, to improve the acceptance of the more economical SST method.

Effect of initial strain and material nonlinearity on the nonlinear static and dynamic response of graphene sheets

Science.gov (United States)

Singh, Sandeep; Patel, B. P.

2018-06-01

Computationally efficient multiscale modelling based on Cauchy-Born rule in conjunction with finite element method is employed to study static and dynamic characteristics of graphene sheets, with/without considering initial strain, involving Green-Lagrange geometric and material nonlinearities. The strain energy density function at continuum level is established by coupling the deformation at continuum level to that at atomic level through Cauchy-Born rule. The atomic interactions between carbon atoms are modelled through Tersoff-Brenner potential. The governing equation of motion obtained using Hamilton's principle is solved through standard Newton-Raphson method for nonlinear static response and Newmark's time integration technique to obtain nonlinear transient response characteristics. Effect of initial strain on the linear free vibration frequencies, nonlinear static and dynamic response characteristics is investigated in detail. The present multiscale modelling based results are found to be in good agreement with those obtained through molecular mechanics simulation. Two different types of boundary constraints generally used in MM simulation are explored in detail and few interesting findings are brought out. The effect of initial strain is found to be greater in linear response when compared to that in nonlinear response.

Hybrid Piezoelectric/Fiber-Optic Sensor Sheets

Science.gov (United States)

Lin, Mark; Qing, Xinlin

2004-01-01

Hybrid piezoelectric/fiber-optic (HyPFO) sensor sheets are undergoing development. They are intended for use in nondestructive evaluation and long-term monitoring of the integrity of diverse structures, including aerospace, aeronautical, automotive, and large stationary ones. It is anticipated that the further development and subsequent commercialization of the HyPFO sensor systems will lead to economic benefits in the form of increased safety, reduction of life-cycle costs through real-time structural monitoring, increased structural reliability, reduction of maintenance costs, and increased readiness for service. The concept of a HyPFO sensor sheet is a generalization of the concept of a SMART Layer(TradeMark), which is a patented device that comprises a thin dielectric film containing an embedded network of distributed piezoelectric actuator/sensors. Such a device can be mounted on the surface of a metallic structure or embedded inside a composite-material structure during fabrication of the structure. There is has been substantial interest in incorporating sensors other than piezoelectric ones into SMART Layer(TradeMark) networks: in particular, because of the popularity of the use of fiber-optic sensors for monitoring the "health" of structures in recent years, it was decided to incorporate fiber-optic sensors, giving rise to the concept of HyPFO devices.

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.

Process research on non-CZ silicon material

Science.gov (United States)

1982-01-01

High risk, high payoff research areas associated with he process for producing photovoltaic modules using non-CZ sheet material are investigated. All investigations are being performed using dendritic web silicon, but all processes are directly applicable to other ribbon forms of sheet material. The technical feasibility of forming front and back junctions in non-CZ silicon using liquid dopant techniques was determined. Numerous commercially available liquid phosphorus and boron dopant solutions are investigated. Temperature-time profiles to achieve N(+) and P(+) sheet resistivities of 60 + or - 10 and 40 + or - s10 ohms per square centimeter respectively are established. A study of the optimal method of liquid dopant application is performed. The technical feasibility of forming a liquid applied diffusion mask to replace the more costly chemical vapor deposited SiO2 diffusion mask was also determined.

Laser cutting of laminated sheet material: a modeling exercise

Science.gov (United States)

de Graaf, Roelof F.; Meijer, Johan

1997-08-01

Laser cutting has been investigated for a number of aluminum-synthetic laminates, newly developed materials for the aeronautic and automotive industry. The materials consist of alternating aluminum and synthetic layers. It is shown that these materials can be cut at rates comparable to those of homogeneous aluminum alloys. The cuts show little dross attachment. Also some damage on the synthetic layers has to be accepted. These results initiated a modeling exercise, which resulted in a numerical simulation code. The applied cutting model is based on describing the material in several horizontal layers, each with its own specific thermophysical and optical properties. The separate layers are coupled by known mass, energy and force balanced equations.

Numerical modelling in friction lap joining of aluminium alloy and carbon-fiber-reinforced-plastic sheets

Science.gov (United States)

Das, A.; Bang, H. S.; Bang, H. S.

2018-05-01

Multi-material combinations of aluminium alloy and carbon-fiber-reinforced-plastics (CFRP) have gained attention in automotive and aerospace industries to enhance fuel efficiency and strength-to-weight ratio of components. Various limitations of laser beam welding, adhesive bonding and mechanical fasteners make these processes inefficient to join metal and CFRP sheets. Friction lap joining is an alternative choice for the same. Comprehensive studies in friction lap joining of aluminium to CFRP sheets are essential and scare in the literature. The present work reports a combined theoretical and experimental study in joining of AA5052 and CFRP sheets using friction lap joining process. A three-dimensional finite element based heat transfer model is developed to compute the temperature fields and thermal cycles. The computed results are validated extensively with the corresponding experimentally measured results.

New radiation warning sign

International Nuclear Information System (INIS)

Mac Kenzie, C.; Mason, C.

2006-01-01

Full text: Radiation accidents involving orphan radioactive sources have happened as a result of people not recognizing the radiation trefoil symbol or from being illiterate and not understanding a warning statement on the radiation source. The trefoil symbol has no inherent meaning to people that have not been instructed in its use. A new radiation warning sign, to supplement the existing trefoil symbol, has been developed to address these issues. Human Factors experts, United Nations member states, and members of the international community of radiation protection professionals were consulted for input on the design of a new radiation warning sign that would clearly convey the message of 'Danger- Run Away- Stay Away' when in close proximity to a dangerous source of radiation. Cultural differences of perception on various warning symbols were taken into consideration and arrays of possible signs were developed. The signs were initially tested in international children for identification with the desired message and response. Based on these test results and further input from radiation protection professionals, five warning signs were identified as the most successful in conveying the desired message and response. These five signs were tested internationally in eleven countries by a professional survey company to determine the best sign for this purpose. The conclusion of the international testing is presented. The new radiation warning sign is currently a draft ISO standard under committee review. The design of the propose d radiation warning sign and the proposed implementation strategy outlined in the draft ISO standard is presented. (authors)

76 FR 11509 - Brass Sheet and Strip From France, Germany, Italy, and Japan

Science.gov (United States)

2011-03-02

...)] Brass Sheet and Strip From France, Germany, Italy, and Japan AGENCY: United States International Trade... and strip from France, Germany, Italy, and Japan. SUMMARY: The Commission hereby gives notice that it... France, Germany, Italy, and Japan would be likely to lead to continuation or recurrence of material...

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.

Integration and embedding of vital signs sensors and other devices into textiles

OpenAIRE

Abreu, Maria José Araújo Marques; Carvalho, Helder; Catarino, André P.; Rocha, A. M.

2010-01-01

The development of ubiquitous vital sign monitoring has become a very up-to-date research theme for many academics and industrial companies in the last years. With new materials and integration techniques, it is possible to implement vital sign monitoring in an economic manner, directly into textile products. This unobtrusive presence of sensors is especially important for the monitoring of children or elderly people. This paper focuses on two aspects of sensor integration: Integration of off...

A constitutive model for the superplastic material ALNOVI-1 including leak risk information

NARCIS (Netherlands)

Snippe, Corijn H.C.; Snippe, Q.H.C.; Meinders, Vincent T.; Pietzyk, M.; Kusiak, J.; Majta, J.; Hartley, P.; Lin, J.; Mori, K.

2008-01-01

For some applications, it is important that a formed sheet of material is completely gas tight, therefore it is beneficial to be able to predict whether a formed sheet will be leak tight for gases or not. Superplastic materials show the ability to attain very high plastic strains before failure.

Green's Theorem for Sign Data

OpenAIRE

Houston, Louis M.

2012-01-01

Sign data are the signs of signal added to noise. It is well known that a constant signal can be recovered from sign data. In this paper, we show that an integral over variant signal can be recovered from an integral over sign data based on the variant signal. We refer to this as a generalized sign data average. We use this result to derive a Green's theorem for sign data. Green's theorem is important to various seismic processing methods, including seismic migration. Results in this paper ge...

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

Signed languages and globalization

NARCIS (Netherlands)

Hiddinga, A.; Crasborn, O.

2011-01-01

Deaf people who form part of a Deaf community communicate using a shared sign language. When meeting people from another language community, they can fall back on a flexible and highly context-dependent form of communication called international sign, in which shared elements from their own sign

On the temporal dynamics of sign production: An ERP study in Catalan Sign Language (LSC).

Science.gov (United States)

Baus, Cristina; Costa, Albert

2015-06-03

This study investigates the temporal dynamics of sign production and how particular aspects of the signed modality influence the early stages of lexical access. To that end, we explored the electrophysiological correlates associated to sign frequency and iconicity in a picture signing task in a group of bimodal bilinguals. Moreover, a subset of the same participants was tested in the same task but naming the pictures instead. Our results revealed that both frequency and iconicity influenced lexical access in sign production. At the ERP level, iconicity effects originated very early in the course of signing (while absent in the spoken modality), suggesting a stronger activation of the semantic properties for iconic signs. Moreover, frequency effects were modulated by iconicity, suggesting that lexical access in signed language is determined by the iconic properties of the signs. These results support the idea that lexical access is sensitive to the same phenomena in word and sign production, but its time-course is modulated by particular aspects of the modality in which a lexical item will be finally articulated. Copyright © 2015 Elsevier B.V. All rights reserved.

Experimental Tests on Bending Behavior of Profiled Steel Sheeting Dry Board Composite Floor with Geopolymer Concrete Infill

Directory of Open Access Journals (Sweden)

Mohd Isa Jaffar

Full Text Available Abstract Profiled Steel Sheet Dry Board (PSSDB system is a lightweight composite structure comprises Profiled Steel Sheeting and Dry Board connected by self-drilling and self-tapping screws. This study introduced geopolymer concrete, an eco-friendly material without cement content as an infill material in the PSSDB floor system to highlight its effect onto the PSSDB (with full and half-size dry boards floor system's stiffness and strength. Experimental tests on various full scale PSSDB floor specimens were conducted under uniformly distributed transverse loads. Results illustrate that the rigidity of the panel with geopolymer concrete infill with half-size dry board (HBGPC increases by 43% relative to that of the panel with normal concrete infill with full-size dry board (FBNC. The developed finite-element modeling (FEM successfully predicts the behavior of FBGPC model with 94.8% accuracy. Geopolymer concrete infill and dry board size influence the strength panel, infill contact stiffness, and mid-span deflection of the profiled steel sheeting/dry board (PSSDB flooring system.

Size-dependent deformation behavior of nanocrystalline graphene sheets

Energy Technology Data Exchange (ETDEWEB)

Yang, Zhi [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Huang, Yuhong [College of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062, Shaanxi (China); Ma, Fei, E-mail: mafei@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Sun, Yunjin [Faculty of Food Science and Engineering, Beijing University of Agriculture, Beijing Key Laboratory of Agricultural Product Detection and Control of Spoilage Organisms and Pesticide Residue, Beijing Laboratory of Food Quality and Safety, Beijing 102206 (China); Xu, Kewei, E-mail: kwxu@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Department of Physics and Opt-electronic Engineering, Xi’an University of Arts and Science, Xi’an 710065, Shaanxi (China); Chu, Paul K., E-mail: paul.chu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

2015-08-15

Highlights: • MD simulation is conducted to study the deformation of nanocrystalline graphene. • Unexpectedly, the elastic modulus decreases with the grain size considerably. • But the fracture stress and strain are nearly insensitive to the grain size. • A composite model with grain domains and GBs as two components is suggested. - Abstract: Molecular dynamics (MD) simulation is conducted to study the deformation behavior of nanocrystalline graphene sheets. It is found that the graphene sheets have almost constant fracture stress and strain, but decreased elastic modulus with grain size. The results are different from the size-dependent strength observed in nanocrystalline metals. Structurally, the grain boundaries (GBs) become a principal component in two-dimensional materials with nano-grains and the bond length in GBs tends to be homogeneously distributed. This is almost the same for all the samples. Hence, the fracture stress and strain are almost size independent. As a low-elastic-modulus component, the GBs increase with reducing grain size and the elastic modulus decreases accordingly. A composite model is proposed to elucidate the deformation behavior.

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.

Stability of high-speed lithium sheet jets for the neutron source in Boron Neutron Capture Therapy (BNCT)

International Nuclear Information System (INIS)

Nakagawa, Masamichi; Takahashi, Minoru; Aritomi, Masanori; Kobayashi, Toru

2014-01-01

The stability of high-speed liquid lithium sheet jets was analytically studied for the neutron source in Boron Neutron Capture Therapy (BNCT), which makes cancers and tumors curable with cell-level selections and hence high QOL. The object of our research is to realize the thin and high-speed plane sheet jets of liquid lithium in a high-vacuum as an accelerator target. Linear analysis approach is made to the stability on thin plane sheet jets of liquid lithium in a high-vacuum, and then our analytical results were compared with the previous experimental ones. We proved that the waves of surface tension on thin lithium sheet jets in a high-vacuum are of supercritical flows and neutral stable under about 17.4 m/s in flow velocity and that the fast non-dispersive anti-symmetric waves are more significant than the very slow dispersive symmetric waves. We also formulated the equation of shrinking angle in isosceles-triangularly or isosceles-trapezoidal shrinking sheet jets corresponding to the Mach angle of supersonic gas flows. This formula states universally the physical meaning of Weber number of sheet jets on the wave of surface tension in supercritical flows. We obtained satisfactory prospects (making choice of larger flow velocity U and larger thickness of sheet a) to materialize a liquid target of accelerator in BNCT. (author)

Autocorrelation descriptor improvements for QSAR: 2DA_Sign and 3DA_Sign

Science.gov (United States)

Sliwoski, Gregory; Mendenhall, Jeffrey; Meiler, Jens

2016-03-01

Quantitative structure-activity relationship (QSAR) is a branch of computer aided drug discovery that relates chemical structures to biological activity. Two well established and related QSAR descriptors are two- and three-dimensional autocorrelation (2DA and 3DA). These descriptors encode the relative position of atoms or atom properties by calculating the separation between atom pairs in terms of number of bonds (2DA) or Euclidean distance (3DA). The sums of all values computed for a given small molecule are collected in a histogram. Atom properties can be added with a coefficient that is the product of atom properties for each pair. This procedure can lead to information loss when signed atom properties are considered such as partial charge. For example, the product of two positive charges is indistinguishable from the product of two equivalent negative charges. In this paper, we present variations of 2DA and 3DA called 2DA_Sign and 3DA_Sign that avoid information loss by splitting unique sign pairs into individual histograms. We evaluate these variations with models trained on nine datasets spanning a range of drug target classes. Both 2DA_Sign and 3DA_Sign significantly increase model performance across all datasets when compared with traditional 2DA and 3DA. Lastly, we find that limiting 3DA_Sign to maximum atom pair distances of 6 Å instead of 12 Å further increases model performance, suggesting that conformational flexibility may hinder performance with longer 3DA descriptors. Consistent with this finding, limiting the number of bonds in 2DA_Sign from 11 to 5 fails to improve performance.

Sign language recognition and translation: a multidisciplined approach from the field of artificial intelligence.

Science.gov (United States)

Parton, Becky Sue

2006-01-01

In recent years, research has progressed steadily in regard to the use of computers to recognize and render sign language. This paper reviews significant projects in the field beginning with finger-spelling hands such as "Ralph" (robotics), CyberGloves (virtual reality sensors to capture isolated and continuous signs), camera-based projects such as the CopyCat interactive American Sign Language game (computer vision), and sign recognition software (Hidden Markov Modeling and neural network systems). Avatars such as "Tessa" (Text and Sign Support Assistant; three-dimensional imaging) and spoken language to sign language translation systems such as Poland's project entitled "THETOS" (Text into Sign Language Automatic Translator, which operates in Polish; natural language processing) are addressed. The application of this research to education is also explored. The "ICICLE" (Interactive Computer Identification and Correction of Language Errors) project, for example, uses intelligent computer-aided instruction to build a tutorial system for deaf or hard-of-hearing children that analyzes their English writing and makes tailored lessons and recommendations. Finally, the article considers synthesized sign, which is being added to educational material and has the potential to be developed by students themselves.

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

Post-Heat Treatment and Mechanical Assessment of Polyvinyl Alcohol Nanofiber Sheet Fabricated by Electrospinning Technique

Directory of Open Access Journals (Sweden)

Mahir Es-saheb

2014-01-01

Full Text Available Polyvinyl alcohol (PVA sheets based nanofibers were produced by electrospinning technique. Postheat treatment of the produced PVA sheets with temperatures both below and above Tg to improve the mechanical properties of this material is conducted. The morphology, microstructures, and thermal degradation of the nanofibers sheets produced were investigated using scanning electron microscopy (SEM, transmission electron microscope (TEM, and thermal gravimetric analysis (TGA. Produced nanofibers are compact, and entangled with each other, with diameters from around 150 to 210. Some mechanical characteristics of the successfully produced PVA sheets, and heat-treated, are then conducted and assessed employing uniaxial tensile tests at different speeds ranging from 1 mm/min to 100 mm/min. The tensile test results obtained show that the PVA sheets are strain rate sensitive with increasing strength as the speed (i.e., strain rate increases. The yield tensile stress ranges from 2.411 to 6.981 MPa, the ductility (i.e., elongation percent from ∼21 to 60%, and Young modulus ranges from 103 to 0.137 KPa. However, for heat-treated samples, it is found that the yield strength increases almost by ∼35–40% more than the values of untreated cases with values reaching up to about 3.627–9.63 MPa.

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...

Machining of the nuclear tube sheet with small hole diameter

International Nuclear Information System (INIS)

Lin Lifeng

2010-01-01

Regarding the tube sheet for the heat exchanger of Qinshan Phase II extension project, its material is 00Cr19Ni10 forgings, the tube sheet thickness is 125 mm, requiring 178-φ10.35 0 +0.05 hole, the tube array shall take the shape of equilateral triangle, the center distance is 15 mm, and the tube hole roughness is Ra 3.2. The guide sleeve shall be adopted for positioning prior to machining of the high precision small hole of the thick tube sheet, and the gun drill and BTA drill shall be adopted for testing, finally BTA drilling with internal chip removal shall be adopted, this method shall overcome the disadvantage factor of BTA drilling and shall be the new approach for drilling. The diameter of BTA drill is φ10.34 mm. The machined hole diameter shall be φ10.375-φ10.355 mm. The ellipticity of the tube hole shall be less than 0.01 mm, the pipe bridge dimension shall be 4.6 mm, conforming to the requirement of the drawing. The paper presents the precautions during machining so as to provide the reference for the similar pipe hole machining in the future. (author)

Efficiency analysis and assessment of interlocking PVC sheet piling walls

International Nuclear Information System (INIS)

Emam, A.A.

2005-01-01

The use of PVC sheet piling in marine environments offers a number of unique advantages that include weight saving, corrosion resistance and environmentally safe material. In this study, one of the widely used classical methods as well as a finite element analysis are used to analyze such sheet piling walls. The analysis focuses on the effect of some important parameters on the wall global behavior, bending moments, stresses and deflections. The parameters include wall cross-section, wall height, embedment depth, number and spacing of anchor rods, and type of soil and loading conditions. Furthermore, the effect of the shape of the wall cross-section and the location of the interlocking joints has been studied by using plane frame and arch-like models. Results indicate that the finite element modeling is an effective tool for numerical approximation of soil-structure interaction problems. The required theoretical embedment depth is nearly 30 % of the clear wall height. Also, the modulus of subgrade reaction has a minor effect on both cantilever wall and one anchor sheet-pile wall. Finally, lateral (horizontal) action shows that deep sections tend to behave like an arch under radial loading which might increase normal stresses at some critical sections

British Sign Name Customs

Science.gov (United States)

Day, Linda; Sutton-Spence, Rachel

2010-01-01

Research presented here describes the sign names and the customs of name allocation within the British Deaf community. While some aspects of British Sign Language sign names and British Deaf naming customs differ from those in most Western societies, there are many similarities. There are also similarities with other societies outside the more…

Negation switching invariant signed graphs

Directory of Open Access Journals (Sweden)

Deepa Sinha

2014-04-01

Full Text Available A signed graph (or, $sigraph$ in short is a graph G in which each edge x carries a value $\\sigma(x \\in \\{-, +\\}$ called its sign. Given a sigraph S, the negation $\\eta(S$ of the sigraph S is a sigraph obtained from S by reversing the sign of every edge of S. Two sigraphs $S_{1}$ and $S_{2}$ on the same underlying graph are switching equivalent if it is possible to assign signs `+' (`plus' or `-' (`minus' to vertices of $S_{1}$ such that by reversing the sign of each of its edges that has received opposite signs at its ends, one obtains $S_{2}$. In this paper, we characterize sigraphs which are negation switching invariant and also see for what sigraphs, S and $\\eta (S$ are signed isomorphic.

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

Wayfinding Sign pada Ruang Pameran Tetap di Museum Nasional Indonesia – Jakarta

Directory of Open Access Journals (Sweden)

Heru Budi Kusuma

2018-05-01

Full Text Available Wayfinding atau orientasi topografi, merupakan kemampuan menentukan lokasi, menemukan tempat dalam fasilitas gedung. Sebagai media penunjuk arah, Wayfinding Sign yang diterapkan pada ruang pameran tetap belum memenuhi kebutuhan yang dapat memberikan informasi yang cukup, mengenai arah mana yang harus dituju untuk mencapai area tertentu, warna-warna yang tercantum dalam panel informasi pun tidak memberikan arti tertentu. Permasalahan pada Wayfinding Sign pada ruang pameran tetap yang dianalisis meliputi: Ukuran; dimensi tanda yang proporsional terhadap luas area dimana tanda tersebut berada,sehingga memungkinkan tanda tersebut dapat mudah terlihat. Warna; berkaitan dengan warna pada tanda telah sesuai peruntukannya dan memperhatikan warna disekitar tanda berada. Kontras; berkaitan dengan estetika tanda yang dominan terhadap kondisi disekitar tanda sehingga tanda tampak eksistensinya. Intensitas; berkaitan terhadap sesuatu yang dapat memberikan stimulus sehingga menarik perhatian terhadap tanda. Posisi ; berkaitan dengan perletakan tanda yang memperhatikan jangkauan penglihatan pengunjung yang mengarah ketempat tanda tersebut berada. Untuk memfokuskan penelitian dan menemukan hubungan antara satu data dengan data yang lain, maka penelitian ini menggunakan metode penelitian kualitatif. Data hasil observasi, pengukuran, deskripsi, dan analisis data dengan teknik Triangulasi Data diperoleh kesimpulan sebagai berikut: Directional Sign; menggunakan tanda ‘warna’ yang tidak ada hubungannya dengan lokasi lantai ruang pameran dan nuansa warna ruangan yang ditunjukan, dan terdapat sign yang menginformasikan arah yang tidak tepat. Informational Sign; tanda yang memberikan informasi tentang materi koleksi yang didisplay dalam ruang pameran tetap, sudah sesuai dan efektif. Identificational Sign; perletakannya yang tidak tepat sehingga menggangu kenyamanan pengunjung dalam membaca informasinya dan membuat posisi membaca yang tidak sehat dan aman

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

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