Development of the fabrication of ultra-low density ploy (4-methyl-1-pentene) (PMP) foams by thermal induced phase-inversion technique

International Nuclear Information System (INIS)

Zhang Lin; Wang Chaoyang; Luo Xuan; Du Kai; Tu Haiyan; Fan Hong; Luo Qing; Yuan Guanghui; Huang Lizhen

2003-01-01

By thermally induced phase-inversion technique, ploy (4-methyl-1-pentene) (PMP) foams are successfully prepared; the density and pore size are 3-80 mg/cm 3 and 1-20 μm respectively. Durene/naphthalene (60/40) is confirmed as the suitable solvent/nonsolvent binary system. The PMP's thermal properties are characterized by TG-DSC system. It is found that the foams thermal properties depend on the density. The thermal analysis method is utilized to measure the gelation of PMP in the binary solvent/nonsolvent system. The range of gelation temperature is preliminarily determined. The influence of mixture system composition and the cooling rate during the making of foams is discussed. TG-DSC is applied to determine the thermal properties of low-density PMP foams prepared in the laboratory. And the effect of density change on the thermal stability of foams are studied. The thermal analysis data play a great role in improving the foam quality. (authors)

On the Feasibility of Very-Low-Density Pure Metal Foams as Bright High-Energy X-ray Sources

Science.gov (United States)

Colvin, Jeffrey; Felter, Thomas

2003-10-01

We have used the Busquet approximation (M. Busquet, Phys. Fluids B 5(11), 4191 (1993)) to explore calculationally what the possible x-ray conversion efficiencies into the K-band would be from irradiating very-low-density pure metal foams with tens of kilojoules of 1/3-micron laser light. We will discuss the advantages of pure metal foams as bright high-energy x-ray sources, and some results of this calculational study. We will also present our ideas for how to fabricate pure metal foams with densities of a few milligrams per cubic centimeter. This work was performed under the auspices of the US Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Thermo-mechanical characterisation of low density carbon foams and composite materials for the ATLAS upgrade

CERN Document Server

Isaac, Bonad

As a result of the need to increase the luminosity of the Large Hadron Collider (LHC) at CERN-Geneva by 2020, the ATLAS detector requires an upgraded inner tracker. Up- grading the ATLAS experiment is essential due to higher radiation levels and high particle occupancies. The design of this improved inner tracker detector involves development of silicon sensors and their support structures. These support structures need to have well un- derstood thermal properties and be dimensionally stable in order to allow efficient cooling of the silicon and accurate track reconstruction. The work presented in this thesis is an in- vestigation which aims to qualitatively characterise the thermal and mechanical properties of the materials involved in the design of the inner tracker of the ATLAS upgrade. These materials are silicon carbide foam (SiC foam), low density carbon foams such as PocoFoam and Allcomp foam, Thermal Pyrolytic Graphite (TPG), carbon/carbon and Carbon Fibre Re- inforced Polymer (CFRP). The work involve...

Fracture behavior of low-density replicated aluminum alloy foams

NARCIS (Netherlands)

Amsterdam, E.; Goodall, R.; Mortensen, A.; Onck, P. R.; De Hosson, J. Th. M.

2008-01-01

Tensile tests have been performed on replicated aluminum alloy foams of relative density between 4.5% and 8%. During the test the electrical resistance was measured with a four-point set-up and the displacements along the gage section were measured using a digital image correlation (DIC) technique.

Direct Laser Writing of Low-Density Interdigitated Foams for Plasma Drive Shaping [Direct Laser Writing of Low Density Nanostitched Foams for Plasma Drive Shaping

International Nuclear Information System (INIS)

Oakdale, James S.; Smith, Raymond F.; Forien, Jean-Baptiste; Smith, William L.; Ali, Suzanne J.

2017-01-01

Monolithic porous bulk materials have many promising applications ranging from energy storage and catalysis to high energy density physics. High resolution additive manufacturing techniques, such as direct laser writing via two photon polymerization (DLW-TPP), now enable the fabrication of highly porous microlattices with deterministic morphology control. In this work, DLW-TPP is used to print millimeter-sized foam reservoirs (down to 0.06 g cm –3 ) with tailored density-gradient profiles, where density is varied by over an order of magnitude (for instance from 0.6 to 0.06 g cm –3 ) along a length of <100 µm. Taking full advantage of this technology, however, is a multiscale materials design problem that requires detailed understanding of how the different length scales, from the molecular level to the macroscopic dimensions, affect each other. The design of these 3D-printed foams is based on the brickwork arrangement of 100 × 100 × 16 µm 3 log-pile blocks constructed from sub-micrometer scale features. A block-to-block interdigitated stitching strategy is introduced for obtaining high density uniformity at all length scales. Lastly, these materials are used to shape plasma-piston drives during ramp-compression of targets under high energy density conditions created at the OMEGA Laser Facility.

Collapse mechanisms of metal foam matrix composites under static and dynamic loading conditions

Energy Technology Data Exchange (ETDEWEB)

Linul, Emanoil, E-mail: emanoil.linul@upt.ro [Department of Mechanics and Strength of Materials, Politehnica University of Timisoara, 1 Mihai Viteazu Avenue, 300 222 Timisoara (Romania); Marsavina, Liviu [Department of Mechanics and Strength of Materials, Politehnica University of Timisoara, 1 Mihai Viteazu Avenue, 300 222 Timisoara (Romania); Kováčik, Jaroslav [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 13 Bratislava (Slovakia)

2017-04-06

The collapse mechanisms of metal foam matrix composites under static and dynamic loading conditions were experimentally and analytically investigated. Closed-cell aluminium foam AlSi10 with 325±10 kg/m{sup 3} density was used as core material, while stainless-steel-mesh is the faces materials. Prior to characterizing the composite sandwich structure, the stainless steel mesh face material and closed-cell aluminium foam were characterized by tensile testing and compression testing, respectively. Experimental tests were performed on sandwich beams using both High Speed Camera and Digital Image Correlation system for strain distribution. All experimental tests were performed at room temperature with constant crosshead speed of 1.67×10{sup −4} m/s for static tests and 2 m/s impact loading speed for dynamic tests. Two main deformation behaviours of investigated metal foam matrix composites were observed following post-failure collapse: face failure and core shear. It was showed that the initiation, propagation and interaction of failure modes depend on the type of loading, constituent material properties and geometrical parameters.

Method for providing a low density high strength polyurethane foam

Science.gov (United States)

Whinnery, Jr., Leroy L.; Goods, Steven H.; Skala, Dawn M.; Henderson, Craig C.; Keifer, Patrick N.

2013-06-18

Disclosed is a method for making a polyurethane closed-cell foam material exhibiting a bulk density below 4 lbs/ft.sup.3 and high strength. The present embodiment uses the reaction product of a modified MDI and a sucrose/glycerine based polyether polyol resin wherein a small measured quantity of the polyol resin is "pre-reacted" with a larger quantity of the isocyanate in a defined ratio such that when the necessary remaining quantity of the polyol resin is added to the "pre-reacted" resin together with a tertiary amine catalyst and water as a blowing agent, the polymerization proceeds slowly enough to provide a stable foam body.

A kinetic approach to modeling the manufacture of high density strucutral foam: Foaming and polymerization

Energy Technology Data Exchange (ETDEWEB)

Rao, Rekha R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Mondy, Lisa Ann [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Noble, David R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Brunini, Victor [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Roberts, Christine Cardinal [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Long, Kevin Nicholas [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Soehnel, Melissa Marie [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Celina, Mathias C. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Wyatt, Nicholas B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Thompson, Kyle R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Tinsley, James

2015-09-01

We are studying PMDI polyurethane with a fast catalyst, such that filling and polymerization occur simultaneously. The foam is over-packed to tw ice or more of its free rise density to reach the density of interest. Our approach is to co mbine model development closely with experiments to discover new physics, to parameterize models and to validate the models once they have been developed. The model must be able to repres ent the expansion, filling, curing, and final foam properties. PMDI is chemically blown foam, wh ere carbon dioxide is pr oduced via the reaction of water and isocyanate. The isocyanate also re acts with polyol in a competing reaction, which produces the polymer. A new kinetic model is developed and implemented, which follows a simplified mathematical formalism that decouple s these two reactions. The model predicts the polymerization reaction via condensation chemis try, where vitrification and glass transition temperature evolution must be included to correctly predict this quantity. The foam gas generation kinetics are determined by tracking the molar concentration of both water and carbon dioxide. Understanding the therma l history and loads on the foam due to exothermicity and oven heating is very important to the results, since the kinetics and ma terial properties are all very sensitive to temperature. The conservation eq uations, including the e quations of motion, an energy balance, and thr ee rate equations are solved via a stabilized finite element method. We assume generalized-Newtonian rheology that is dependent on the cure, gas fraction, and temperature. The conservation equations are comb ined with a level set method to determine the location of the free surface over time. Results from the model are compared to experimental flow visualization data and post-te st CT data for the density. Seve ral geometries are investigated including a mock encapsulation part, two configur ations of a mock stru ctural part, and a bar geometry to

Production of lightweight foam glass (invited talk)

DEFF Research Database (Denmark)

Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

The foam glass production allows low cost recycling of postconsumer glass and industrial waste materials as foaming agent or as melt resource. Foam glass is commonly produced by utilising milled glass mixed with a foaming agent. The powder mixture is heat-treated to around 10^3.7 – 10^6 Pa s, which...... result in viscous sintering and subsequent foaming of the glass melt. The porous glass melt is cooled down to room temperature to freeze-in the foam structure. The resulting foam glass is applied in constructions as a light weight material to reduce load bearing capacity and as heat insulating material...... in buildings and industry. We foam panel glass from old televisions with different foaming agents. We discuss the foaming ability and the foaming mechanism of different foaming systems. We compare several studies to define a viscous window for preparing low density foam glass. However, preparing foam glass...

Cementitious Stabilization of Mixed Wastes with High Salt Loadings

International Nuclear Information System (INIS)

Spence, R.D.; Burgess, M.W.; Fedorov, V.V.; Downing, D.J.

1999-01-01

Salt loadings approaching 50 wt % were tolerated in cementitious waste forms that still met leach and strength criteria, addressing a Technology Deficiency of low salt loadings previously identified by the Mixed Waste Focus Area. A statistical design quantified the effect of different stabilizing ingredients and salt loading on performance at lower loadings, allowing selection of the more effective ingredients for studying the higher salt loadings. In general, the final waste form needed to consist of 25 wt % of the dry stabilizing ingredients to meet the criteria used and 25 wt % water to form a workable paste, leaving 50 wt % for waste solids. The salt loading depends on the salt content of the waste solids but could be as high as 50 wt % if all the waste solids are salt

Indentation of aluminium foam at low velocity

Directory of Open Access Journals (Sweden)

Shi Xiaopeng

2015-01-01

Full Text Available The indentation behaviour of aluminium foams at low velocity (10 m/s ∼ 30 m/s was investigated both in experiments and numerical simulation in this paper. A flat-ended indenter was used and the force-displacement history was recorded. The Split Hopkinson Pressure bar was used to obtain the indentation velocity and forces in the dynamic experiments. Because of the low strength of the aluminium foam, PMMA bar was used, and the experimental data were corrected using Bacon's method. The energy absorption characteristics varying with impact velocity were then obtained. It was found that the energy absorption ability of aluminium foam gradually increases in the quasi-static regime and shows a significant increase at ∼10 m/s velocity. Numerical simulation was also conducted to investigate this process. A 3D Voronoi model was used and models with different relative densities were investigated as well as those with different failure strain. The indentation energy increases with both the relative density and failure strain. The analysis of the FE model implies that the significant change in energy absorption ability of aluminium foam in indentation at ∼10 m/s velocity may be caused by plastic wave effect.

Mechanical Characterization of Rigid Polyurethane Foams

Energy Technology Data Exchange (ETDEWEB)

Lu, Wei-Yang [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Mechanics of Materials

2014-12-01

Foam materials are used to protect sensitive components from impact loading. In order to predict and simulate the foam performance under various loading conditions, a validated foam model is needed and the mechanical properties of foams need to be characterized. Uniaxial compression and tension tests were conducted for different densities of foams under various temperatures and loading rates. Crush stress, tensile strength, and elastic modulus were obtained. A newly developed confined compression experiment provided data for investigating the foam flow direction. A biaxial tension experiment was also developed to explore the damage surface of a rigid polyurethane foam.

Numerical study on heat transfer characteristics of liquid-fueled molten salt using OpenFOAM

International Nuclear Information System (INIS)

Jeong, Yeong Shin; Bang, In Cheol

2017-01-01

To pursue sustainability and safety enhancement of nuclear energy, molten salt reactor is regarded as a promising candidate among various types of gen-IV reactors. Besides, pyroprocessing, which treats molten salt containing fission products, should consider safety related to decay heat from fuel material. For design of molten salt-related nuclear system, it is required to consider both thermal-hydraulic characteristics and neutronic behaviors for demonstration. However, fundamental heat transfer study of molten salt in operation condition is not easy to be experimentally studied due to its large scale, high temperature condition as well as difficulties of treating fuel material. >From that reason, numerical study can have benefit to investigate behaviors of liquid-fueled molten salt in real condition. In this study, open source CFD package OpenFOAM was used to analyze liquid-fueled molten salt loop having internal heat source as a first step of research. Among various molten salts considered as a candidate of liquid fueled molten salt reactors, in this study, FLiBe was chosen as liquid salt. For simulating heat generation from fuel material within fluid flow, volumetric heat source was set for fluid domain and OpenFOAM solver was modified as fvOptions as customized. To investigate thermal-hydraulic behavior of molten salt, CFD model was developed and validated by comparing experimental results in terms of heat transfer and pressure drop. As preliminary stage, 2D cavity simulations were performed to validate the modeling capacity of modified solver of OpenFOAM by comparison with those of ANSYS-CFX. In addition, cases of external heat flux and internal heat source were compared to configure the effect of heat source setting in various operation condition. As a result, modified solver of OpenFOAM considering internal heat source have sufficient modeling capacity to simulate liquid-fueled molten salt systems including heat generation cases. (author)

Heating of low-density CHO-foam layers by means of soft X-rays

Energy Technology Data Exchange (ETDEWEB)

Rosmej, O.N., E-mail: o.rosmej@gsi.de [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, 164291 Darmstadt (Germany); Bagnoud, V.; Eisenbarth, U. [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, 164291 Darmstadt (Germany); Vatulin, V.; Zhidkov, N.; Suslov, N.; Kunin, A.; Pinegin, A. [All Russian Scientific Research Institute of Experimental Physics, RFNC-VNIIEF, Mira St. 37, Sarov (Russian Federation); Schaefer, D.; Nisius, Th.; Wilhein, Th. [RheinAhrCampus Remagen, Institute for X-optics, Suedallee 2, 53424 Remagen (Germany); Rienecker, T.; Wiechula, J.; Jacoby, J. [Goethe University, Frankfurt am Main (Germany); Zhao, Y. [Institute of Modern Physics, CAS, Nanchang Road 509, 730000 Lanzhou (China); Vergunova, G.; Borisenko, N. [Lebedev Physical Institute, Leninskii Prospekt, 65 Moscow (Russian Federation); Orlov, N. [Joint Institute for High Temperatures RAS, Institute for High Energy Density, Izhorskaya. 13, building 2, 125412 Moscow (Russian Federation)

2011-10-11

Interaction of soft X-ray thermal radiation with polymer foam layers has been studied experimentally. Indirectly heated CHO-foams were used to create a plasma target for applications in combined heavy ion beam-laser experiments that are aimed at investigation of the heavy ion energy loss in ionized matter. In this work, we report experimental results on heating of low Z foams by means of the Planckian radiation generated in gold hohlraums. The experimental goal was to study the hohlraum radiation field, duration of the soft X-ray pulse, the conversion efficiency of the laser energy into soft X-rays, measurements of the absorption properties of foam layers and parameters of the foam targets heated by the Plankian radiation.

Heating of low-density CHO-foam layers by means of soft X-rays

International Nuclear Information System (INIS)

Rosmej, O.N.; Bagnoud, V.; Eisenbarth, U.; Vatulin, V.; Zhidkov, N.; Suslov, N.; Kunin, A.; Pinegin, A.; Schaefer, D.; Nisius, Th.; Wilhein, Th.; Rienecker, T.; Wiechula, J.; Jacoby, J.; Zhao, Y.; Vergunova, G.; Borisenko, N.; Orlov, N.

2011-01-01

Interaction of soft X-ray thermal radiation with polymer foam layers has been studied experimentally. Indirectly heated CHO-foams were used to create a plasma target for applications in combined heavy ion beam-laser experiments that are aimed at investigation of the heavy ion energy loss in ionized matter. In this work, we report experimental results on heating of low Z foams by means of the Planckian radiation generated in gold hohlraums. The experimental goal was to study the hohlraum radiation field, duration of the soft X-ray pulse, the conversion efficiency of the laser energy into soft X-rays, measurements of the absorption properties of foam layers and parameters of the foam targets heated by the Plankian radiation.

Numerical modelling of closed-cell aluminium foam under dynamic loading

Science.gov (United States)

Hazell, Paul; Kader, M. A.; Islam, M. A.; Escobedo, J. P.; Saadatfar, M.

2015-06-01

Closed-cell aluminium foams are extensively used in aerospace and automobile industries. The understanding of their behaviour under impact loading conditions is extremely important since impact problems are directly related to design of these engineering structures. This research investigates the response of a closed-cell aluminium foam (CYMAT) subjected to dynamic loading using the finite element software ABAQUS/explicit. The aim of this research is to numerically investigate the material and structural properties of closed-cell aluminium foam under impact loading conditions with interest in shock propagation and its effects on cell wall deformation. A μ-CT based 3D foam geometry is developed to simulate the local cell collapse behaviours. A number of numerical techniques are applied for modelling the crush behaviour of aluminium foam to obtain the more accurate results. The simulation results are compared with experimental data. Comparison of the results shows a good correlation between the experimental results and numerical predictions.

An investigation of Crater Diameter on Plain Slab Foamed Concrete Rice Husk Ash (FCRHA Exposed to Low Impact Loading

Directory of Open Access Journals (Sweden)

Hadipramana Josef

2017-01-01

Full Text Available As sustainable material building and construction, the foamed concrete (FC in this investigation was modified by adding the Rice Husk Ash (RHA as sand replacement to increase its strength. Furthermore, this modification material (is called FCRHA treated on impact loading. This investigation was motivated when the plain slab of FCRHA subjected to small impactor, then the nose impactor over all would penetrate into slab target due to porosity of FCRHA. The experimental produced plain slabs FCRHA and FC (as a control with 1400 kg/m3 and 1600 Kg/m3 of densities. In impact test all plain slabs exposed by 40 mm steel blunt nose impactor with various impact velocities. The result showed the crater which produced by impact loading was not found spalling, scabbing, radial crack and widely cratering. This local damage occurred when porosity of FCRHA took over the impact loading. The nose impactor over all considered have been successful penetrated into slab of FCRHA and FC. Therefore, the diameter of crater equals to diameter of impactor. With this certainty, the prediction penetration depth on plain slab FCRHA (also FC can be determined in future investigation. In addition, the penetration of impactor on FCRHA with low impact velocity give the same impression on penetration impactor with high impact velocity on FC.

Fundamental properties of high-quality carbon nanofoam: from low to high density

Directory of Open Access Journals (Sweden)

Natalie Frese

2016-12-01

Full Text Available Highly uniform samples of carbon nanofoam from hydrothermal sucrose carbonization were studied by helium ion microscopy (HIM, X-ray photoelectron spectroscopy (XPS, and Raman spectroscopy. Foams with different densities were produced by changing the process temperature in the autoclave reactor. This work illustrates how the geometrical structure, electron core levels, and the vibrational signatures change when the density of the foams is varied. We find that the low-density foams have very uniform structure consisting of micropearls with ≈2–3 μm average diameter. Higher density foams contain larger-sized micropearls (≈6–9 μm diameter which often coalesced to form nonspherical μm-sized units. Both, low- and high-density foams are comprised of predominantly sp2-type carbon. The higher density foams, however, show an advanced graphitization degree and a stronger sp3-type electronic contribution, related to the inclusion of sp3 connections in their surface network.

Fabrication of a Low Density Carbon Fiber Foam and Its Characterization as a Strain Gauge

Directory of Open Access Journals (Sweden)

Claudia C. Luhrs

2014-05-01

Full Text Available Samples of carbon nano-fiber foam (CFF, essentially a 3D solid mat of intertwined nanofibers of pure carbon, were grown using the Constrained Formation of Fibrous Nanostructures (CoFFiN process in a steel mold at 550 °C from a palladium particle catalysts exposed to fuel rich mixtures of ethylene and oxygen. The resulting material was studied using Scanning Electron Microscopy (SEM, Energy Dispersive Spectroscopy (EDX, Surface area analysis (BET, and Thermogravimetric Analysis (TGA. Transient and dynamic mechanical tests clearly demonstrated that the material is viscoelastic. Concomitant mechanical and electrical testing of samples revealed the material to have electrical properties appropriate for application as the sensing element of a strain gauge. The sample resistance versus strain values stabilize after a few compression cycles to show a perfectly linear relationship. Study of microstructure, mechanical and electrical properties of the low density samples confirm the uniqueness of the material: It is formed entirely of independent fibers of diverse diameters that interlock forming a tridimensional body that can be grown into different shapes and sizes at moderate temperatures. It regains its shape after loads are removed, is light weight, presents viscoelastic behavior, thermal stability up to 550 °C, hydrophobicity, and is electrically conductive.

Fabrication of a Low Density Carbon Fiber Foam and Its Characterization as a Strain Gauge.

Science.gov (United States)

Luhrs, Claudia C; Daskam, Chris D; Gonzalez, Edwin; Phillips, Jonathan

2014-05-08

Samples of carbon nano-fiber foam (CFF), essentially a 3D solid mat of intertwined nanofibers of pure carbon, were grown using the Constrained Formation of Fibrous Nanostructures (CoFFiN) process in a steel mold at 550 °C from a palladium particle catalysts exposed to fuel rich mixtures of ethylene and oxygen. The resulting material was studied using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX), Surface area analysis (BET), and Thermogravimetric Analysis (TGA). Transient and dynamic mechanical tests clearly demonstrated that the material is viscoelastic. Concomitant mechanical and electrical testing of samples revealed the material to have electrical properties appropriate for application as the sensing element of a strain gauge. The sample resistance v ers us strain values stabilize after a few compression cycles to show a perfectly linear relationship. Study of microstructure, mechanical and electrical properties of the low density samples confirm the uniqueness of the material: It is formed entirely of independent fibers of diverse diameters that interlock forming a tridimensional body that can be grown into different shapes and sizes at moderate temperatures. It regains its shape after loads are removed, is light weight, presents viscoelastic behavior, thermal stability up to 550 °C, hydrophobicity, and is electrically conductive.

Investigation of Mild Steel Thin-Wall Tubes in Unfilled and Foam-Filled Triangle, Square, and Hexagonal Cross Sections Under Compression Load

Science.gov (United States)

Rajak, Dipen Kumar; Kumaraswamidhas, L. A.; Das, S.

2018-02-01

This study has examined proposed structures with mild steel-reinforced LM30 aluminum (Al) alloy having diversely unfilled and 10 wt.% SiCp composite foam-filled tubes for improving axial compression performance. This class of material has novel physical, mechanical, and electrical properties along with low density. In the present experiment, Al alloy foams were prepared by the melt route technique using metal hydride powder as a foaming agent. Crash energy phenomena for diverse unfilled and foam-filled in mild steel thin-wall tubes (triangular, square and hexagonal) were studied as well. Compression deformation investigation was conducted at strain rates of 0.001-0.1/s for evaluating specific energy absorption (SEA) under axial loading conditions. The results were examined to measure plateau stress, maximum densification strain, and deformation mechanism of the materials. Specific energy absorption and total energy absorption capacities of the unfilled and filled sections were determined from the compressive stress-strain curves, which were then compared with each other.

Implosion dynamics of a megampere wire-array Z-pinch with an inner low-density foam shell at the Angara-5-1 facility

International Nuclear Information System (INIS)

Aleksandrov, V. V.; Bolkhovitinov, E. A.; Volkov, G. S.; Grabovski, E. V.; Gritsuk, A. N.; Medovshchikov, S. F.; Oleinik, G. M.; Rupasov, A. A.; Frolov, I. N.

2016-01-01

The implosion dynamics of a pinch with a highly inhomogeneous initial axial distribution of the load mass was studied experimentally. A cascade array consisting of a double nested tungsten wire array and a coaxial inner cylindrical shell located symmetrically with respect to the high-voltage electrodes was used as a load of the Angara-5-1 high-current generator. The cylindrical foam shell was half as long as the cathode− anode gap, and its diameter was equal to the diameter of the inner wire array. It is shown experimentally that two stages are typical of the implosion dynamics of such a load: the formation of two separate pinches formed as a result of implosion of the wire array near the cathode and anode and the subsequent implosion of the central part of the load containing the cylindrical foam shell. The conditions are determined at which the implosion of the central part of the pinch with the foam cylinder is preceded by intense irradiation of the foam with the soft X-ray (SXR) emission generated by the near-electrode pinches and converting it into the plasma state. Using such a load, which models the main elements of the scheme of a dynamic hohlraum for inertial confinement fusion, it is possible to increase the efficiency of interaction between the outer accelerated plasma sheath and the inner foam shell by preionizing the foam with the SXR emission of the near-electrode pinches.

Experimental investigation on temperature distribution of foamed concrete filled steel tube column under standard fire

Science.gov (United States)

Kado, B.; Mohammad, S.; Lee, Y. H.; Shek, P. N.; Kadir, M. A. A.

2018-04-01

Standard fire test was carried out on 3 hollow steel tube and 6 foamed concrete filled steel tube columns. Temperature distribution on the columns was investigated. 1500 kg/m3 and 1800 kg/m3 foamed concrete density at 15%, 20% and 25% load level are the parameters considered. The columns investigated were 2400 mm long, 139.7 mm outer diameter and 6 mm steel tube thickness. The result shows that foamed concrete filled steel tube columns has the highest fire resistance of 43 minutes at 15% load level and low critical temperature of 671 ºC at 25% load level using 1500 kg/m3 foamed concrete density. Fire resistance of foamed concrete filled column increases with lower foamed concrete strength. Foamed concrete can be used to provide more fire resistance to hollow steel column or to replace normal weight concrete in concrete filled columns. Since filling hollow steel with foamed concrete produce column with high fire resistance than unfilled hollow steel column. Therefore normal weight concrete can be substituted with foamed concrete in concrete filled column, it will reduces the self-weight of the structure because of its light weight at the same time providing the desired fire resistance.

Low Velocity Impact Properties of Aluminum Foam Sandwich Structural Composite

Directory of Open Access Journals (Sweden)

ZHAO Jin-hua

2018-01-01

Full Text Available Sandwich structural composites were prepared by aluminum foam as core materials with basalt fiber(BF and ultra-high molecular weight polyethylene(UHMWPE fiber composite as faceplate. The effect of factors of different fiber type faceplates, fabric layer design and the thickness of the corematerials on the impact properties and damage mode of aluminum foam sandwich structure was studied. The impact properties were also analyzed to compare with aluminum honeycomb sandwich structure. The results show that BF/aluminum foam sandwich structural composites has bigger impact damage load than UHMWPE/aluminum foam sandwich structure, but less impact displacement and energy absorption. The inter-layer hybrid fabric design of BF and UHMWPE has higher impact load and energy absorption than the overlay hybrid fabric design faceplate sandwich structure. With the increase of the thickness of aluminum foam,the impact load of the sandwich structure decreases, but the energy absorption increases. Aluminum foam sandwich structure has higher impact load than the aluminum honeycomb sandwich structure, but smaller damage energy absorption; the damage mode of aluminum foam core material is mainly the fracture at the impact area, while aluminum honeycomb core has obvious overall compression failure.

Structural testing of salt loaded HEPA filters for WIPP

International Nuclear Information System (INIS)

Smith, P.R.; Leslie, I.H.; Hensel, E.C.; Shultheis, T.M.; Walls, J.R.

1993-01-01

The ventilation studies of the Waste Isolation Pilot Plant described in this paper were performed by personnel from New Mexico State Univ. in collaboration with Sandia National Laboratories, Los Alamos National Laboratory and Westinghouse Corporation. High efficiency particulate air filters (0.61m by 0.61m by 0.3m) of the type in use at the Waste Isolation Pilot Plant were loaded with salt aerosol provided from that site. The structural strength of salt-loaded, high-efficiency filters was investigated at two humidity levels, high (75%RH) and low (13-14% RH), by subjecting the filters to pressure transients of the types expected from tornadoes. Filters loaded under the high humidity condition proved to have a greater structural strength than did the filters loaded under the low humidity conditions, when both types were subjected to tornado-like pressure pulses. This unexpected results was apparently due to the crystallization of salt upon the wire face guard of the HEPA filter loaded under the high humidity condition which kept salt from penetrating the filter medium while still providing a substantial pressure drop at the standard flow rate. Results are also presented for HEPA filters pre-conditioned at 100% RH before structural testing and for HEPA filters in series with pre-filters

Effects of a new foam formulation of ketoprofen lysine salt in experimental models of inflammation and hyperalgesia.

Science.gov (United States)

Daffonchio, L; Bestetti, A; Clavenna, G; Fedele, G; Ferrari, M P; Omini, C

1995-05-01

The anti-inflammatory and analgesic profile of a new topical foam formulation of ketoprofen lysine salt (CAS 57469-78-0, Artrosilene Schiuma, KLS-foam) was characterized in comparison with marketed gel formulations containing KLS (KLS-gel) or diclofenac diethylammonium salt (DCF-gel). KLS-foam dose-dependently inhibited oedema formation and hyperalgesia induced by subplantar injection of carrageenan or substance P, being more potent than KLS-gel. At equieffective anti-inflammatory doses, KLS-foam provided a more pronounced analgesic effect than DCF-gel. KLS-foam also markedly inhibited exudate formation and prostaglandin production induced by subcutaneous implantation of carrageenan soaked sponges. In carrageenan induced paw inflammation, KLS-foam provided the same anti-inflammatory effect as orally administered KLS, but induced significantly less gastric damages. Oral administration of KLS resulted in sustained systemic absorption of ketoprofen, whereas after topical application of KLS-foam no appreciable ketoprofen plasma levels were detected. These data support the anti-inflammatory and particularly the analgesic effectiveness of the new foam formulation of KLS, a finding that, together with the high gastric tolerability, further emphasizes the usefulness of KLS-foam in the treatment of localized flogistic diseases and associated pain.

Ultra Low Density Shape Memory Polymer Foams With Tunable Physicochemical Properties for Treatment of intracranial Aneurysms

Energy Technology Data Exchange (ETDEWEB)

Singhal, Pooja [Texas A & M Univ., College Station, TX (United States)

2013-12-01

Shape memory polymers (SMPs) are a rapidly emerging class of smart materials that can be stored in a deformed temporary shape, and can actively return to their original shape upon application of an external stimulus such as heat, pH or light. This behavior is particularly advantageous for minimally invasive biomedical applications comprising embolic/regenerative scaffolds, as it enables a transcatheter delivery of the device to the target site. The focus of this work was to exploit this shape memory behavior of polyurethanes, and develop an efficient embolic SMP foam device for the treatment of intracranial aneurysms.In summary, this work reports a novel family of ultra low density polymer foams which can be delivered via a minimally invasive surgery to the aneurysm site, actuated in a controlled manner to efficiently embolize the aneurysm while promoting physiological fluid/blood flow through the reticulated/open porous structure, and eventually biodegrade leading to complete healing of the vasculature.

Study on the technique for precision measurement of density of SiO_2 foam shells

International Nuclear Information System (INIS)

Ma Xiaojun; Gao Dangzhong; Meng Jie

2013-01-01

The measuring method based on vertical scanning interference and combined with the relation between refraction index and density of SiO_2 foam shells is introduced, and the relation is analyzed according to formulas of Lorentz-Lorenz and Gladstone-Dale. The experimental result and measuring uncertainty evaluation indicate that the precision measurement of density of low density SiO_2 foam shells can be realized by using the vertical scanning interference technique and combining with Gladstone and Dale analysis method, and the measuring uncertainty is about 5%. (authors)

Influence of the glass particle size on the foaming process and physical characteristics of foam glasses

DEFF Research Database (Denmark)

König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

2016-01-01

We have prepared low-density foam glasses from cathode-ray-tube panel glass using carbon and MnO2 as the foaming agents. The effect of the glass particle size on the foaming process, the apparent density and the pore morphology is revealed. The results show that the foaming is mainly caused...... by the reduction of manganese. Foam glasses with a density of

Low Overpotential and High Current CO2 Reduction with Surface Reconstructed Cu Foam Electrodess

KAUST Repository

Min, Shixiong

2016-06-23

While recent reports have demonstrated that oxide-derived Cu-based electrodes exhibit high selectivity for CO2 reduction at low overpotential, the low catalytic current density (<2 mA/cm2 at -0.45 V vs. RHE) still largely limits its applications for large-scale fuel synthesis. Here we report an extremely high current density for CO2 reduction at low overpotential using a Cu foam electrode prepared by air-oxidation and subsequent electroreduction. Apart from possessing three-dimensional (3D) open frameworks, the resulting Cu foam electrodes prepared at higher temperatures exhibit enhanced electrochemically active surface area and distinct surface structures. In particular, the Cu foam electrode prepared at 500 °C exhibits an extremely high geometric current density of ~9.4 mA/cm2 in CO2-satrurated 0.1 M KHCO3 aqueous solution and achieving ~39% CO and ~23% HCOOH Faradaic efficiencies at -0.45 V vs. RHE. The high activity and significant selectivity enhancement are attributable to the formation of abundant grain-boundary supported active sites and preferable (100) and (111) facets as a result of reconstruction of Cu surface facets. This work demonstrates that the structural integration of Cu foam with open 3D frameworks and the favorable surface structures is a promising strategy to develop an advanced Cu electrocatalyst that can operate at high current density and low overpotential for CO2 reduction.

Zinc layered hydroxide salts: intercalation and incorporation into low-density polyethylene

OpenAIRE

Jaerger,Silvia; Zimmermann,Ademir; Zawadzki,Sonia Faria; Wypych,Fernando; Amico,Sandro Campos

2014-01-01

In this study, polymer composites using low-density polyethylene (LDPE) and layered hydroxide salts (LHS) were synthesized. The following compositions of LHS were obtained Zn5(OH)8(An-)2/n.yH2O, where A was varied in order to obtain hydrophilic (A = NO3 -) or hydrophobic (A = DDS- – dodecyl sulfate or DBS- – dodecyl benzene sulfonate). Synthesis was carried out by co-precipitation in alkaline medium and drying, being followed by characterization via Fourier-transform infrared spectroscopy, th...

Experimental Characterization of the Energy Absorption of Functionally Graded Foam Filled Tubes Under Axial Crushing Loads

Science.gov (United States)

Ebrahimi, Saeed; Vahdatazad, Nader; Liaghat, Gholamhossein

2018-03-01

This paper deals with the energy absorption characterization of functionally graded foam (FGF) filled tubes under axial crushing loads by experimental method. The FGF tubes are filled axially by gradient layers of polyurethane foams with different densities. The mechanical properties of the polyurethane foams are firstly obtained from axial compressive tests. Then, the quasi-static compressive tests are carried out for empty tubes, uniform foam filled tubes and FGF filled tubes. Before to present the experimental test results, a nonlinear FEM simulation of the FGF filled tube is carried out in ABAQUS software to gain more insight into the crush deformation patterns, as well as the energy absorption capability of the FGF filled tube. A good agreement between the experimental and simulation results is observed. Finally, the results of experimental test show that an FGF filled tube has excellent energy absorption capacity compared to the ordinary uniform foam-filled tube with the same weight.

Tensile and fracture behavior of polymer foams

International Nuclear Information System (INIS)

Kabir, Md. E.; Saha, M.C.; Jeelani, S.

2006-01-01

Tensile and mode-I fracture behavior of cross-linked polyvinyl chloride (PVC) and rigid polyurethane (PUR) foams are examined. Tension tests are performed using prismatic bar specimens and mode-I fracture tests are performed using single edge notched bend (SENB) specimens under three-point bending. Test specimens are prepared from PVC foams with three densities and two different levels of cross-linking, and PUR foam with one density. Tension and quasi-static fracture tests are performed using a Zwick/Rowell test machine. Dynamic fracture tests are performed using a DYNATUP model 8210 instrumented drop-tower test set up at three different impact energy levels. Various parameters such as specimen size, loading rate, foam density, cross-linking, crack length, cell orientation (flow and rise-direction) and solid polymer material are studied. It is found that foam density and solid polymer material have a significant effect on tensile strength, modulus, and fracture toughness of polymer foams. Level of polymer cross-linking is also found to have a significant effect on fracture toughness. The presence of cracks in the rise- and flow direction as well as loading rate has minimal effect. Dynamic fracture behavior is found to be different as compared to quasi-static fracture behavior. Dynamic fracture toughness (K d ) increases with impact energy. Examination of fracture surfaces reveals that the fracture occurs in fairly brittle manner for all foam materials

Low-density hydrocarbon foams for laser fusion targets: Progress report, 1986

International Nuclear Information System (INIS)

Chen, C.; Cook, R.C.; Haendler, B.L.; Hair, L.M.; Kong, F.M.; Letts, S.A.

1987-06-01

We describe progress made during 1986 in the development of direct-drive hydrocarbon foam targets for laser fusion. The foam materials are polystyrene and resorcinolformaldehyde. The processes for making the foams, their properties, characterization techniques, and the relationships of their properties to target specifications are presented. In the final section, we discuss statistical experimental design techniques that are being used to optimize the foams. 12 refs., 14 figs., 2 tabs

Progress in development of low density polymer foams for the ICF Program

International Nuclear Information System (INIS)

Letts, S.A.; Lucht, L.M.; Morgan, R.J.; Cook, R.C.; Tillotson, T.M.; Mercer, M.B.; Miller, D.E.

1985-01-01

This report describes the status of CH foam development with densities of 50 mg/ccs and cell sizes of 1 μm for the ICF Program. Two approaches that both involve polymer phase separation are being investigated. The first involves a gelation-crystallization of high molecular weight polyethylene from solution, whereas the second approach involves the modification of the phase separation morphology of water-styrene emulsions by molecularly-tailored surfactants followed by polymerization of the continuous styrene phase

A phenomenological constitutive model for low density polyurethane foams

International Nuclear Information System (INIS)

Neilsen, M.K.; Morgan, H.S.; Krieg, R.D.

1987-04-01

Results from a series of hydrostatic and triaxial compression tests which were performed on polyurethane foams are presented in this report. These tests indicate that the volumetric and deviatoric parts of the foam behavior are strongly coupled. This coupling behavior could not be captured with any of several commonly used plasticity models. Thus, a new constitutive model was developed. This new model was based on a decomposition of the foam response into two parts: (1) response of the polymer skeleton, and (2) response of the air inside the cells. The air contribution was completely volumetric. The new constitutive model was implemented in two finite element codes, SANCHO and PRONTO. Results from a series of analyses completed with these codes indicated that the new constitutive model captured all of the foam behaviors that had been observed in the experiments. Finally, a typical dynamic problem was analyzed using the new constitutive model and other constitutive models to demonstrate differences between the models. Results from this series of analyses indicated that the new constitutive model generated displacement and acceleration predictions that were between predictions obtained using the other models. This result was expected. 9 refs., 45 figs., 4 tabs

Preliminary study of semi-refined carrageenan (SRC) as secondary gelling agent in natural rubber (NR) latex foam

Science.gov (United States)

Norhazariah, S.; Azura, A. R.; Azahari, B.; Sivakumar, R.

2017-12-01

Semi-refined carrageenan (SRC) product is considerably cheaper and easier to produce as a natural polysaccharide, which was utilized in food and other product application. However, the application in latex is limited. The aim of this work is to evaluate the SRC produced from low industrial grade seaweed (LIGS) in the latex foam application. The FTIR spectra showed the SRC produced as kappa type carrageenan with lower sulfur content compared to native LIGS. NR latex foam is produced by using the Dunlop method with some modifications. The effect of SRC loading as a secondary gelling agent in NR latex foam is investigated. The density and morphology of the NR latex foam with the addition of the SRC are analyzed. NR latex foam density increased with SRC loading and peaked at 1.8 phr SRC. The addition of SRC has induced the bigger cell size compared to the cell size of the control NR latex foam, as shown in the optical micrograph. It can be concluded that SRC LIGS could be acted as secondary gelling agent in NR latex foam.

Foam Glass for Construction Materials

DEFF Research Database (Denmark)

Petersen, Rasmus Rosenlund

2016-01-01

Foaming is commonly achieved by adding foaming agents such as metal oxides or metal carbonates to glass powder. At elevated temperature, the glass melt becomes viscous and the foaming agents decompose or react to form gas, causing a foamy glass melt. Subsequent cooling to room temperature, result...... in a solid foam glass. The foam glass industry employs a range of different melt precursors and foaming agents. Recycle glass is key melt precursors. Many parameters influence the foaming process and optimising the foaming conditions is very time consuming. The most challenging and attractive goal is to make...... low density foam glass for thermal insulation applications. In this thesis, it is argued that the use of metal carbonates as foaming agents is not suitable for low density foam glass. A reaction mechanism is proposed to justify this result. Furthermore, an in situ method is developed to optimise...

Low-density hydrocarbon foams for laser fusion targets: Progress report, 1987

International Nuclear Information System (INIS)

Haendler, B.L.; Buckley, S.R.; Chen, C.

1988-06-01

This report describes progress made in the development of direct-drive hydrocarbon foam targets for laser inertial confinement fusion during 1987. The foam materials are polystyrene, resorcinol-formaldehyde, carbonized resorcinol-formaldehyde, and cellulose acetate. The processes for making the foams, their properties, characterization techniques, and the relationship of their properties to target specifications are presented. Progress in the creation and testing of prototype targets is also described

Bio-based Polymer Foam from Soyoil

Science.gov (United States)

Bonnaillie, Laetitia M.; Wool, Richard P.

2006-03-01

The growing bio-based polymeric foam industry is presently lead by plant oil-based polyols for polyurethanes and starch foams. We developed a new resilient, thermosetting foam system with a bio-based content higher than 80%. The acrylated epoxidized soybean oil and its fatty acid monomers is foamed with pressurized carbon dioxide and cured with free-radical initiators. The foam structure and pore dynamics are highly dependent on the temperature, viscosity and extent of reaction. Low-temperature cure hinds the destructive pore coalescence and the application of a controlled vacuum results in foams with lower densities ˜ 0.1 g/cc, but larger cells. We analyze the physics of foam formation and stability, as well as the structure and mechanical properties of the cured foam using rigidity percolation theory. The parameters studied include temperature, vacuum applied, and cross-link density. Additives bring additional improvements: nucleating agents and surfactants help produce foams with a high concentration of small cells and low bulk density. Hard and soft thermosetting foams with a bio content superior to 80% are successfully produced and tested. Potential applications include foam-core composites for hurricane-resistant housing, structural reinforcement for windmill blades, and tissue scaffolds.

Synthesis of low density foam shells for inertial confinement fusion experiments

International Nuclear Information System (INIS)

Lattaud, Cecile

2011-01-01

This work deals with the fabrication process of low density foam shells and the sharp control of their shape (diameter, thickness, density, sphericity, non-concentricity). During this PhD we focused on the non-concentricity criterion which has to be lower than 1%. The shells are synthesized using a microencapsulation process leading to a double emulsion and followed by a thermal polymerization at 60 C. According to the literature, three major parameters, the density of the three phases, the deformations of the shells along the process and the kinetics of the polymerization have a direct influence on the shells non-concentricity. The results obtained showed that when the density gap between the internal water phase and the organic phase increases, the TMPTMA shells non-concentricity improves. A density gap of 0.078 g.cm -3 at 60 C, leads to an average non-concentricity of 2.4% with a yield of shells of 58%. It was also shown that the synthesis process can be considered as reproducible. While using the same internal water phase, equivalent non-concentricity results are obtained using either a straight tube, a tube with areas of constriction or a short wound tube. The time required to fix the shell's shape is at least 20 minutes with thermal polymerization. So, it seems that the time spent by the shells inside the rotating flask allows the centering of the internal water phase inside the organic phase, whatever the circulation process used. In order to get higher polymerization rates and to avoid destabilization phenomena, we then focused our study on photo polymerization. When the synthesis is performed using a UV lamp with an efficient light intensity, the shells have a slightly higher thickness than the shells synthesized by thermal polymerization. Moreover, a really higher yield, around 80%, is achieved with UV polymerization. However, the average non-concentricity of the shells synthesized lays around 20%, which is really high compared to the 2.4% average

Investigation into stress wave propagation in metal foams

Directory of Open Access Journals (Sweden)

Li Lang

2015-01-01

Full Text Available The aim of this study is to investigate stress wave propagation in metal foams under high-speed impact loading. Three-dimensional Voronoi model is established to represent real closed-cell foam. Based on the one-dimensional stress wave theory and Voronoi model, a numerical model is developed to calculate the velocity of elastic wave and shock wave in metal foam. The effects of impact velocity and relative density of metal foam on the stress wave propagation in metal foams are explored respectively. The results show that both elastic wave and shock wave propagate faster in metal foams with larger relative density; with increasing the impact velocity, the shock wave propagation velocity increase, but the elastic wave propagation is not sensitive to the impact velocity.

Fire retardant polyisocyanurate foam

Science.gov (United States)

Riccitiello, S. R.; Parker, J. A.

1972-01-01

Fire retardant properties of low density polymer foam are increased. Foam has pendant nitrile groups which form thermally-stable heterocyclic structures at temperature below degradation temperature of urethane linkages.

Low density lipoprotein labelling characterizes experimentally induced atherosclerotic lesions in rabbits in vivo as to presence of foam cells and endothelial coverage

International Nuclear Information System (INIS)

Virgolini, I.; Sinzinger, H.; Angelberger, P.; O'Grady, J.

1991-01-01

The entry of autologous iodine 125 low density lipoprotein ( 125 I-LDL) into the aortic wall in rabbits was measured. After abdominal endothelium abrasion with a Fogarthy catheter the animals were fed at 1% cholesterol-supplemented diet for 4 weeks. The animals were killed 1-48 h after administration of 25 μCi 125 I-LDL. Local entry of radiolabelled LDL was estimated and correlated to endothelial surface lining and foam cell content, both controlled morphologically. Endothelialized segments showed the lowest entry of 125 I-LDL, the maximum uptake was reached at around 8 h. In de-endothelialized segments the entry was higher and the peak later (12 h), while in re-endothelialized segments a continuous increase in 125 I-LDL entry up to 48 h was measured. Number and extent of foam cells correlated with the entry of LDL. The data indicate the usefulnes of LDL radiolabelling for qualitative in vivo information on surface lining and foam cell content. (orig.)

Polyurethane foam loaded with sodium dodecylsulfate for the extraction of 'quat' pesticides from aqueous medium: Optimization of loading conditions.

Science.gov (United States)

Vinhal, Jonas O; Lima, Claudio F; Cassella, Ricardo J

2016-09-01

The cationic herbicides paraquat, diquat and difenzoquat are largely used in different cultures worldwide. With this, there is an intrinsic risk of environmental contamination when these herbicides achieve natural waters. The goal of this work was to propose a novel and low-cost sorbent for the removal of the cited herbicides from aqueous medium. The proposed sorbent was prepared by loading polyurethane foam with sodium dodecylsulfate. The influence of several parameters (SDS concentration, HCl concentration and shaking time) on the loading process was investigated. The results obtained in this work demonstrated that all studied variables influenced the loading process, having significant effect on the extraction efficiency of the resulted PUF-SDS. At optimized conditions, the PUF was loaded by shaking 200mg of crushed foam with 200mL of a solution containing 5.0×10(-3)molL(-1) SDS and 0.25molL(-1) HCl, for 30min. The obtained PUF-SDS was efficient for removing the three herbicides from aqueous medium, achieving extraction percentages higher than 90%. The sorption process followed a pseudo second-order kinetics, which presented excellent predictive capacity of the amount of herbicide retained with time. Copyright © 2016 Elsevier Inc. All rights reserved.

Structure and Compressive Properties of Invar-Cenosphere Syntactic Foams

Directory of Open Access Journals (Sweden)

Dung Luong

2016-02-01

Full Text Available The present study investigates the mechanical performance of syntactic foams produced by means of the metal powder injection molding process having an Invar (FeNi36 matrix and including cenospheres as hollow particles at weight fractions (wt.% of 5 and 10, respectively, corresponding to approximately 41.6 and 60.0 vol.% in relation to the metal content and at 0.6 g/cm3 hollow particle density. The synthesis process results in survival of cenospheres and provides low density syntactic foams. The microstructure of the materials is investigated as well as the mechanical performance under quasi-static and high strain rate compressive loads. The compressive stress-strain curves of syntactic foams reveal a continuous strain hardening behavior in the plastic region, followed by a densification region. The results reveal a strain rate sensitivity in cenosphere-based Invar matrix syntactic foams. Differences in properties between cenosphere- and glass microsphere-based materials are discussed in relation to the findings of microstructural investigations. Cenospheres present a viable choice as filler material in iron-based syntactic foams due to their higher thermal stability compared to glass microspheres.

Washcoat Deposition of Ni- and Co-ZrO2 Low Surface Area Powders onto Ceramic Open-Cell Foams: Influence of Slurry Formulation and Rheology

Directory of Open Access Journals (Sweden)

Riccardo Balzarotti

2015-12-01

Full Text Available The effect of formulations and procedures to deposit thin active layers based on low surface area powders on complex geometry substrates (open-cell foams was experimentally assessed. An acid-free liquid medium based on water, glycerol, and polyvinyl alcohol was used for powder dispersion, while a dip-coating technique was chosen for washcoat deposition on 30 PPI ceramic open-cell foams. The rheological behavior was explained on the bases of both porosity and actual powder density. It was proved that the use of multiple dippings fulfills flexibility requirements for washcoat load management. Multiple depositions with intermediate flash drying steps at 350 °C were carried out. Washcoat loads in the 2.5 to 22 wt. % range were obtained. Pore clogging was seldom observed in a limited extent in samples with high loading (>20 wt. %. Adhesion, evaluated by means of accelerated stress test in ultrasound bath, pointed out good results of all the deposited layers.

The melt/shrink effect of low density thermoplastics insulates: Cone calorimeter tests

Directory of Open Access Journals (Sweden)

Xu Qiang

2017-01-01

Full Text Available The melt/shrink effects on the fire behavior of low density thermoplastic foam have been studied in a cone calorimeter. The experiments have been performed with four samples of expanded polystyrene foams having different thicknesses and two extruded polystyrene foams. Decrease in surface area and increase in density, characterizing the melt/shrink effect have been measured at different incident heat fluxes. Three of these foams tested have been also examined by burning tests at an incident heat flux of 50 kW/m2. It was assessed that the fire behavior predictions based the current literature models provided incorrect results if the cone test results were applied directly. However, the correct models provided adequate results when the initial burning area and the density of the molten foam were used to correct the initial cone calorimeter data. This communication refers to the fact that both the effective burning area and the density of the molten foam affect the cone calorimeter data, which requires consequent corrections to attain adequate predictions of models about the materials fire behavior.

FOAM FORMATION IN THE SALTSTONE PRODUCTION FACILITY: EVALUATION OF SOURCES AND MITIGATION

Energy Technology Data Exchange (ETDEWEB)

Cozzi, A.

2011-01-18

The Saltstone Production Facility receives waste from Tank 50H for treatment. Influents into Tank 50H include the Effluent Treatment Project waste concentrate, H-Canyon low activity waste and General Purpose Evaporator bottoms, Modular Caustic Side Solvent Extraction Unit decontaminated salt solution, and salt solution from the Deliquification, Dissolution and Adjust campaign. Using the Waste Characterization System (WCS), this study tracks the relative amounts of each influent into Tank 50H, as well as the total content of Tank 50H, in an attempt to identify the source of foaming observed in the Saltstone Production Facility hopper. Saltstone has been using antifoam as part of routine processing with the restart of the facility in December 2006. It was determined that the maximum admix usage in the Saltstone Production Facility, both antifoam and set retarder, corresponded with the maximum concentration of H-Canyon low activity waste in Tank 50H. This paper also evaluates archived salt solutions from Waste Acceptance Criteria analysis for propensity to foam and the antifoam dosage required to mitigate foaming. It was determined that Effluent Treatment Project contributed to the expansion factor (foam formation) and General Purpose Evaporator contributed to foaminess (persistence). It was also determined that undissolved solids contribute to foam persistence. It was shown that additions of Dow Corning Q2-1383a antifoam reduced both the expansion factor and foaminess of salt solutions. The evaluation of foaming in the grout hopper during the transition from water to salt solution indicated that higher water-to-premix ratios tended to produce increased foaming. It was also shown that additions of Dow Corning Q2-1383a antifoam reduced foam formation and persistence.

PRESSURE-IMPULSE DIAGRAM OF MULTI-LAYERED ALUMINUM FOAM PANELS UNDER BLAST PRESSURE

Directory of Open Access Journals (Sweden)

CHANG-SU SHIM

2013-06-01

Full Text Available Anti-terror engineering has increasing demand in construction industry, but basis of design (BOD is normally not clear for designers. Hardening of structures has limitations when design loads are not defined. Sacrificial foam claddings are one of the most efficient methods to protect blast pressure. Aluminum foam can have designed yield strength according to relative density and mitigate the blast pressure below a target transmitted pressure. In this paper, multi-layered aluminum foam panels were proposed to enhance the pressure mitigation by increasing effective range of blast pressure. Through explicit finite element analyses, the performance of blast pressure mitigation by the multi-layered foams was evaluated. Pressure-impulse diagrams for the foam panels were developed from extensive analyses. Combination of low and high strength foams showed better applicability in wider range of blast pressure.

Use of Pd-Pt loaded graphene aerogel on nickel foam in direct ethanol fuel cell

Science.gov (United States)

Tsang, Chi Him A.; Leung, D. Y. C.

2018-01-01

A size customized binder-free bimetallic Pd-Pt loaded graphene aerogel deposited on nickel foam plate (Pd-Pt/GA/NFP) was prepared and used as an electrode for an alkaline direct ethanol fuel cell (DEFC) under room temperature. The effect of fuel concentration and metal composition on the output power density of the DEFC was systematically investigated. Under the optimum fuel concentration, the cell could achieve a value of 3.6 mW cm-2 at room temperature for the graphene electrode with Pd/Pt ratio approaching 1:1. Such results demonstrated the possibility of producing a size customized metal loaded GA/NFP electrode for fuel cell with high performance.

Fabrication of highly insulating foam glass made from CRT panel glass

DEFF Research Database (Denmark)

König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

2015-01-01

We prepared low-density foam glasses from cathode-ray-tube panel glass using carbon and MnO2 as the foaming agents. We investigated the influence of the carbon and MnO2 concentrations, the glass-powder preparation and the foaming conditions on the density and homogeneity of the pore structure...... and the dependence of the thermal conductivity on the foam density. The results show that the moderate foaming effect of the carbon is greatly improved by the addition of MnO2. A density as low as 131 kg m-3 can be achieved with fine glass powder. The foam density has a slight dependence on the carbon and MnO2...... concentrations, but it is mainly affected by the foaming temperature and the time. The thermal conductivity of the foam-glass samples is lower than that of commercial foam glasses with the same density. The lowest value was determined to be 42 mW m-1 K-1 for a foam glass with a density of 131 kg m-3. A further...

Electromagnetic absorber composite made of carbon fibers loaded epoxy foam for anechoic chamber application

International Nuclear Information System (INIS)

Méjean, Chloé; Pometcu, Laura; Benzerga, Ratiba; Sharaiha, Ala; Le Paven-Thivet, Claire; Badard, Mathieu; Pouliguen, Philippe

2017-01-01

Highlights: • Carbon fibers loaded epoxy foam composites are proposed as microwave absorbers. • Dielectric properties (ε′, tanδ) of composites increase with carbon fibers content and length. • S 11 coefficient of a pyramidal prototype was characterized in anechoic chamber. • Epoxy prototype shows better absorption performance than commercial absorber. • S 11 of the prototype is lower than −30 dB (4–18 GHz) at normal and oblique incidences. - Abstract: This paper presents a new electromagnetic absorbing material developed from carbon fibers loaded epoxy foam for an application in anechoic chamber. The composite was developed in order to replace the currently used pyramidal absorbers made of carbon particles loaded polyurethane foam. Epoxy-composites filled with different weight percentages (from 0 wt.% to 4 wt.%) and length (1 and 3 mm) of carbon fibers were achieved. After an optimization of the dispersion of carbon fibers in composite materials, the dielectric properties of the composites were measured using a coaxial-probe in the frequency range 4–18 GHz. Results have shown that the complex permittivity of the composites increases with the amount of charge and also with the length of the carbon fibers. Absorption performance of a prototype prepared with a low concentration (0.5 wt.%) of carbon fibers was measured in an anechoic chamber: it shows a mean gain of 10 dB compared to a commercial absorber.

Electromagnetic absorber composite made of carbon fibers loaded epoxy foam for anechoic chamber application

Energy Technology Data Exchange (ETDEWEB)

Méjean, Chloé; Pometcu, Laura [Institut d’Electronique et de Télécommunications de Rennes, 18 rue Henri Wallon, 22000 Saint-Brieuc (France); Benzerga, Ratiba, E-mail: ratiba.benzerga@univ-rennes1.fr [Institut d’Electronique et de Télécommunications de Rennes, 18 rue Henri Wallon, 22000 Saint-Brieuc (France); Sharaiha, Ala; Le Paven-Thivet, Claire; Badard, Mathieu [Institut d’Electronique et de Télécommunications de Rennes, 18 rue Henri Wallon, 22000 Saint-Brieuc (France); Pouliguen, Philippe [Département Recherche et Innovation Scientifique de la Direction Générale de l’Armement, 7-9 rue des Mathurins, 92221 Bagneux (France)

2017-06-15

Highlights: • Carbon fibers loaded epoxy foam composites are proposed as microwave absorbers. • Dielectric properties (ε′, tanδ) of composites increase with carbon fibers content and length. • S{sub 11} coefficient of a pyramidal prototype was characterized in anechoic chamber. • Epoxy prototype shows better absorption performance than commercial absorber. • S{sub 11} of the prototype is lower than −30 dB (4–18 GHz) at normal and oblique incidences. - Abstract: This paper presents a new electromagnetic absorbing material developed from carbon fibers loaded epoxy foam for an application in anechoic chamber. The composite was developed in order to replace the currently used pyramidal absorbers made of carbon particles loaded polyurethane foam. Epoxy-composites filled with different weight percentages (from 0 wt.% to 4 wt.%) and length (1 and 3 mm) of carbon fibers were achieved. After an optimization of the dispersion of carbon fibers in composite materials, the dielectric properties of the composites were measured using a coaxial-probe in the frequency range 4–18 GHz. Results have shown that the complex permittivity of the composites increases with the amount of charge and also with the length of the carbon fibers. Absorption performance of a prototype prepared with a low concentration (0.5 wt.%) of carbon fibers was measured in an anechoic chamber: it shows a mean gain of 10 dB compared to a commercial absorber.

Uninephrectomy in young age or chronic salt loading causes salt-sensitive hypertension in adult rats

DEFF Research Database (Denmark)

Carlström, Mattias; Sällström, Johan; Skøtt, Ole

2007-01-01

animals raised with normal-salt diet (UNX) or high-salt diet (UNX+HS). In the adult animals, renal and cardiovascular functions were evaluated and blood pressure recorded telemetrically under different sodium conditions (normal, high, and low). Hypertension was present in UNX+HS (122+/-9 mm Hg), UNX (101......+/-3 mm Hg), and HS (96+/-1 mm Hg) groups on normal-salt diets compared with the controls (84+/-2 mm Hg), and the blood pressure was salt sensitive (high- versus normal-salt diet; 23+/-3, 9+/-2, 7+/-2, and 1+/-1 mm Hg, respectively). The hypertensive groups (UNX+HS, UNX, and HS) had increased diuresis......The importance of nephron endowment and salt intake for the development of hypertension is under debate. The present study was designed to investigate whether reduced nephron number, after completion of nephrogenesis, or chronic salt loading causes renal injury and salt-sensitive hypertension...

Effect of slurries density on the properties of ceramic foam produced via polymer replication method

International Nuclear Information System (INIS)

Mohd Al Amin Muhammad Nor; Lee Chain Hong; Hazizan Md Akil; Zainal Ariffin Ahmad

2007-01-01

Ceramic foams are a class of high porosity materials that are used or being considered for a wide range of technological applications. Ceramic foam was produce by polymer replication method. In this process, commercial polymeric sponge was use as template, dipping with ceramic particles slurry, drying and then sintered to yield a replica of the original foams. The study was focus on the fabrication of different density of ceramic foams by varying the density of ceramic slurries (1.1876, 1.2687, 1.3653 and 1.5295 g/cm?3). Properties of ceramic foam produced such as density was characterized accordingly to ASTM C 271-94 and porosity were characterized using Archimedes methods. Compressive and bending strength was performed accordingly to ASTM C1161-94 and C773-88 (1999), respectively. The morphological study was performed using Scanning Electron Microscopy (SEM) and EDX. Density of ceramic foams produced was about 0.5588 and 1.1852 g/cm 3 , where as porosity was around 26.28 and 70.59 %. Compressive and bending strength was increase from strength also increases from 2.60 to 23.07 MPa and 1.20 to 11.10 MPa, respectively, with increasing of slurries density from 1.1876 to 1.3653 g/cm 3 . The SEM micrographs show that the cells structure become denser as the slurries density increased. EDX proved that the ceramic used is porcelain. As conclusion, increasing in slurries density produced ceramic foams with good mechanical properties such as compressive and bending strength and denser body. (Author)

Effect of silica nanoparticles on polyurethane foaming process and foam properties

International Nuclear Information System (INIS)

Francés, A B; Bañón, M V Navarro

2014-01-01

Flexible polyurethane foams (FPUF) are commonly used as cushioning material in upholstered products made on several industrial sectors: furniture, automotive seating, bedding, etc. Polyurethane is a high molecular weight polymer based on the reaction between a hydroxyl group (polyol) and isocyanate. The density, flowability, compressive, tensile or shearing strength, the thermal and dimensional stability, combustibility, and other properties can be adjusted by the addition of several additives. Nanomaterials offer a wide range of possibilities to obtain nanocomposites with specific properties. The combination of FPUF with silica nanoparticles could develop nanocomposite materials with unique properties: improved mechanical and thermal properties, gas permeability, and fire retardancy. However, as silica particles are at least partially surface-terminated with Si-OH groups, it was suspected that the silica could interfere in the reaction of poyurethane formation.The objective of this study was to investigate the enhancement of thermal and mechanical properties of FPUF by the incorporation of different types of silica and determining the influence thereof during the foaming process. Flexible polyurethane foams with different loading mass fraction of silica nanoparticles (0-1% wt) and different types of silica (non treated and modified silica) were synthesized. PU/SiO 2 nanocomposites were characterized by FTIR spectroscopy, TGA, and measurements of apparent density, resilience and determination of compression set. Addition of silica nanoparticles influences negatively in the density and compression set of the foams. However, resilience and thermal stability of the foams are improved. Silica nanoparticles do not affect to the chemical structure of the foams although they interfere in the blowing reaction

Experimental study of the mechanical behaviour of pin reinforced foam core sandwich materials under shear load

International Nuclear Information System (INIS)

Dimassi, M A; Brauner, C; Herrmann, A S

2016-01-01

Sandwich structures with a lightweight closed cell hard foam core have the potential to be used in primary structures of commercial aircrafts. Compared to honeycomb core sandwich, the closed cell foam core sandwich overcomes the issue of moisture take up and makes the manufacturing of low priced and highly integrated structures possible. However, lightweight foam core sandwich materials are prone to failure by localised external loads like low velocity impacts. Invisible cracks could grow in the foam core and threaten the integrity of the structure. In order to enhance the out-of-plane properties of foam core sandwich structures and to improve the damage tolerance (DT) dry fibre bundles are inserted in the foam core. The pins are infused with resin and co-cured with the dry fabric face sheets in an out-of-autoclave process. This study presents the results obtained from shear tests following DIN 53294-standard, on flat sandwich panels. All panels were manufactured with pin-reinforcement manufactured with the Tied Foam Core Technology (TFC) developed by Airbus. The effects of pin material (CFRP and GFRP) and pin volume fraction on the shear properties of the sandwich structure and the crack propagation were investigated and compared to a not pinned reference. It has been concluded that the pin volume fraction has a remarkable effect on the shear properties and damage tolerance of the observed structure. Increasing the pin volume fraction makes the effect of crack redirection more obvious and conserves the integrity of the structure after crack occurrence. (paper)

Properties and Characterization of Kenaf-Filled Natural Rubber Latex Foam

Directory of Open Access Journals (Sweden)

Ahmad Fikri Abdul Karim

2015-12-01

Full Text Available Kenaf powder was incorporated with natural rubber latex (NRL compound and foamed to make natural rubber latex foam (NRLF by using a well known technique called the Dunlop method. Different loadings of kenaf powder were added to NRL compound and was foamed to make NRLF. The mechanical properties, density, compression, thermal, and micro-structural characterization of control NRLF and kenaf incorporated NRLF were studied. Increasing content of kenaf reduced the tensile strength, elongation at break, and compressive strength of a NRLF. Modulus at 100% elongation and density of the NRLF increased with an increase in filler loading. Higher kenaf loading indicated higher elasticity of kenaf-filled NRLF, but the recovery percentage of kenaf-filled NRLF decreased with increasing kenaf loading. From thermogravimetric analysis (TGA result, an increase in the amount of kenaf loading from 1 to 7 phr increased the thermal stability of kenaf-filled NRLF. Morphological and micro-structural characterization performed by using scanning electron microscopy (SEM showed that kenaf powder filled up the micro-sized pores in the open cell structure of kenaf-filled NRLF.

Spectroscopic Characterization of HAN-Based Liquid Gun Propellants and Nitrate Salt Solutions

Science.gov (United States)

1989-01-15

spectra were recorded of bubbles of a concentrated aqueous nitrate solution, mineral oil, and an aqueous surfactant solution. Polymethacrylic acid ...FTIR spectra of droplets of a concentrated aqueous nitrate salt based solution (LGP1845), of solid particles cf polymethacrylic acid packing IO, 3... polymethacrylic acid low density packing foam cut to a 3x4 mnn rectangle was levitated with a low acoustic power. The sample was easily I positioned in the

Amorphous microcellular polytetrafluoroethylene foam film

Science.gov (United States)

Tang, Chongzheng

1991-11-01

We report herein the preparation of novel low-density ultramicrocellular fluorocarbon foams and their application. These fluorocarbon foams are of interest for the biochemistry arena in numerous applications including foodstuff, pharmacy, wine making, beer brewery, fermentation medical laboratory, and other processing factories. All of those require good quality processing programs in which, after eliminating bacterium and virus, compressed air is needed. Ordinarily, compressed air contains bacterium and virus, its size is 0.01 - 2 micrometers fluorocarbon foam films. Having average porous diameter 0.04 - 0.1 micrometers , these are stable to high temperature (280 degree(s)C) and chemical environments, and generally have good engineering and mechanical properties (e.g., low coefficient of thermal expansion, high modulus, and good dimensional stability). Our new process for preparing low density fluorocarbon foams provides materials with unique properties. As such, they offer the possibility for being superior to earlier materials for a number of the filter applications mentioned.

Effect of Pelletized Coconut Fibre on the Compressive Strength of Foamed Concrete

OpenAIRE

Mohd Jaini Zainorizuan; Mokhatar Shahrul Niza; Mohd Yusof Ammar Saifuddin; Zulkiply Syurafarina; Abd Rahman Mohd Hadi

2016-01-01

Foamed concrete is a controlled low density ranging from 400kg/m3 to 1800kg/m3, and hence suitable for the construction of buildings and infrastructures. The uniqueness of foamed concrete is does not use aggregates in order to retain low density. Foamed concrete contains only cement, sand, water and foam agent. Therefore, the consumption of cement is higher in producing a good quality and strength of foamed concrete. Without the present of aggregates, the compressive strength of foamed concre...

Failure mechanisms of aluminium foams under compressive loads

Directory of Open Access Journals (Sweden)

Sáenz, E.

2000-08-01

Full Text Available The purpose of this paper is the investigation of the major failure mechanisms of aluminium foams, which were obtained by powder metallurgy route, under compressive loads. The study was focused on two commonly aluminium alloys AlMg1Si or A 6061 and AlSi12. Due to the fact that the failure mechanisms strongly depend on the density and the macrostructural properties of the material, the mechanical properties always have to be correlated to the structural properties. Therefore, macrostructural investigations were used as a basis to establish the correlation between structural and mechanical properties. This was done with a commercially available image analysis system. The average cell size, the cell size distribution and the cell density (number of cells/area were obtained. In order to evaluate the influence of foaming direction on the cell morphology, some cross sections parallel to the foaming direction were prepared. For the characterization of the mechanical compression properties the compressive or upper yield strength (UYS, the densification strain (eD, the energy absorption (Ea and the efficiency (Eff were obtained. Furthermore, the failure behavior of the samples was in-situ observed with a digital video camera and continuously recorded during the test.

El objetivo de este estudio es investigar los principales mecanismos de fallo de espumas de aluminio sometidas a cargas de compresión. Las espumas metálicas fueron obtenidas mediante el proceso pulvimetalúrgico, utilizándose como materia prima dos aleaciones comerciales AlMg1Si o A 6061 y AlSi12. Debido a que los mecanismos de fallo en este tipo de materiales depende fuertemente de la densidad y las características macroestructurales del material, en este estudio se busca correlacionar las propiedades mecánicas con estas características. La macroestructura se caracterizó mediante análisis de imagen. El tamaño de celda promedio, la distribución de tamaño y la densidad de

Low Overpotential and High Current CO2 Reduction with Surface Reconstructed Cu Foam Electrodess

KAUST Repository

Min, Shixiong; Yang, Xiulin; Lu, Ang-Yu; Tseng, Chien-Chih; Hedhili, Mohamed N.; Li, Lain-Jong; Huang, Kuo-Wei

2016-01-01

for large-scale fuel synthesis. Here we report an extremely high current density for CO2 reduction at low overpotential using a Cu foam electrode prepared by air-oxidation and subsequent electroreduction. Apart from possessing three-dimensional (3D) open

Low Cost P/M Aluminum Syntactic Foam for Blade Containment in Turbine Engines, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The proposed Phase I SBIR proposes a low density (0.75-1.2g/cc)syntactic aluminum foam energy absorber co-manufactured inside a composite fan case for turbine...

Solid cellulose nanofiber based foams - Towards facile design of sustained drug delivery systems

DEFF Research Database (Denmark)

Svagan, Anna J; Benjamins, Jan-Willem; Al-Ansari, Zeinab

2016-01-01

acceptable surfactant (lauric acid sodium salt). The drug was suspended in the wet-stable foams followed by a drying step to obtain dry foams. Flexible cellular solid materials of different thicknesses, shapes and drug loadings (up to 50wt%) could successfully be prepared. The drug was released from...... the solid foams in a diffusion-controlled, sustained manner due to the presence of intact air bubbles which imparted a tortuous diffusion path. The diffusion coefficient was assessed using Franz cells and shown to be more than one order of magnitude lower for the cellular solids compared to the bubble...

Zinc layered hydroxide salts: intercalation and incorporation into low-density polyethylene

Directory of Open Access Journals (Sweden)

Silvia Jaerger

2014-12-01

Full Text Available In this study, polymer composites using low-density polyethylene (LDPE and layered hydroxide salts (LHS were synthesized. The following compositions of LHS were obtained Zn5(OH8(An-2/n.yH2O, where A was varied in order to obtain hydrophilic (A = NO3- or hydrophobic (A = DDS- - dodecyl sulfate or DBS- - dodecyl benzene sulfonate. Synthesis was carried out by co-precipitation in alkaline medium and drying, being followed by characterization via Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy. A variable amount of filler was then incorporated into the LDPE via extrusion, which was then injection molded to obtain specimens for evaluating tensile properties (Young's modulus, tensile strength, strain at break and toughness. For comparison, the sodium salts of the surfactants (NaDDS and NaDBS were also used as fillers in LDPE. The X-ray diffraction results indicated that the hydrophobic LHS were exfoliated in the polymer matrix, whereas the hydrophilic LHS was only delaminated. In the LDPE composites, melting and crystallization temperatures were nearly constant, along with the crystallinity indexes. The mechanical properties were mainly varied when the organophilic LHS was used. Overall, fillers based on LHS, especially those containing hydrophobic anions, may be interesting alternatives in the production of reinforced thermoplastics.

Nanostructured metal foams: synthesis and applications

Energy Technology Data Exchange (ETDEWEB)

Luther, Erik P [Los Alamos National Laboratory; Tappan, Bryce [Los Alamos National Laboratory; Mueller, Alex [Los Alamos National Laboratory; Mihaila, Bogdan [Los Alamos National Laboratory; Volz, Heather [Los Alamos National Laboratory; Cardenas, Andreas [Los Alamos National Laboratory; Papin, Pallas [Los Alamos National Laboratory; Veauthier, Jackie [Los Alamos National Laboratory; Stan, Marius [Los Alamos National Laboratory

2009-01-01

Fabrication of monolithic metallic nanoporous materials is difficult using conventional methodology. Here they report a relatively simple method of synthesizing monolithic, ultralow density, nanostructured metal foams utilizing self-propagating combustion synthesis of novel metal complexes containing high nitrogen energetic ligands. Nanostructured metal foams are formed in a post flame-front dynamic assembly with densities as low as 0.011 g/cc and surface areas as high as 270 m{sup 2}/g. They have produced metal foams via this method of titanium, iron, cobalt, nickel, zirconium, copper, palladium, silver, hafnium, platinum and gold. Microstructural features vary as a function of composition and process parameters. Applications for the metal foams are discussed including hydrogen absorption in palladium foams. A model for the sorption kinetics of hydrogen in the foams is presented.

Cellulose nanocrystals reinforced foamed nitrile rubber nanocomposites.

Science.gov (United States)

Chen, Yukun; Zhang, Yuanbing; Xu, Chuanhui; Cao, Xiaodong

2015-10-05

Research on foamed nitrile rubber (NBR)/cellulose nanocrystals (CNs) nanocomposites is rarely found in the literatures. In this paper, CNs suspension and NBR latex was mixed to prepared the foamed NBR/CNs nanocomposites. We found that the CNs mainly located in the cell walls, effectively reinforcing the foamed NBR. The strong interaction between the CNs and NBR matrix restricted the mobility of NBR chains surrounding the CNs, hence increasing the crosslink density of the NBR matrix. CNs exhibited excellent reinforcement on the foamed NBR: a remarkable increase nearly 76% in the tensile strength of the foamed nanocomposites was achieved with a load of only 15 phr CNs. Enhanced mechanical properties make the foamed NBR/CNs nanocomposites a promising damping material for industrial applications with a potential to reduce the petroleum consumption. Copyright © 2015 Elsevier Ltd. All rights reserved.

Triaxial extensometer for volumetric strain measurement in a hydro-compression loading test for foam materials

International Nuclear Information System (INIS)

Feng, Bo; Xu, Ming-long; Zhao, Tian-fei; Zhang, Zhi-jun; Lu, Tian-jian

2010-01-01

A new strain gauge-based triaxial extensometer (radial extensometers x, y and axial extensometer z) is presented to improve the volumetric strain measurement in a hydro-compression loading test for foam materials. By the triaxial extensometer, triaxial deformations of the foam specimen can be measured directly, from which the volumetric strain is determined. Sensitivities of the triaxial extensometer are predicted using a finite-element model, and verified through experimental calibrations. The axial extensometer is validated by conducting a uniaxial compression test in aluminium foam and comparing deformation measured by the axial extensometer to that by the advanced optical 3D deformation analysis system ARAMIS; the result from the axial extensometer agrees well with that from ARAMIS. A new modus of two-wire measurement and transmission in a hydrostatic environment is developed to avoid the punching and lead sealing techniques on the pressure vessel for the hydro-compression test. The effect of hydrostatic pressure on the triaxial extensometer is determined through an experimental test. An application in an aluminium foam hydrostatic compression test shows that the triaxial extensometer is effective for volumetric strain measurement in a hydro-compression loading test for foam materials

Processing, Characterization, and Modeling of Polymer/Clay Nanocomposite Foams

Science.gov (United States)

Jo, Choonghee; Naguib, Hani E.

2007-04-01

The effects of the material parameters and processing conditions on the foam morphologies, and mechanical properties of polymer/clay nanocomposite foams were studied. Microcellular closed-cell nanocomposite foams were manufactured with poly(methylmethacrylate) (PMMA) and high density polyethylene (HDPE), where the nanoclay loadings of 0.5, 1.0, and 2.0 wt% were used. The effect of clay contents and foaming conditions on the volume expansion ratio, cell size, elastic modulus, tensile strength, and elongation at break were investigated and compared between amorphous and semicrystalline polymers. An elastic modulus model for tensile behavior of foams was proposed by using the micromechanics theory. The model was expressed in terms of microstructural properties of polymer and physical properties of the foams. The tensile experimental data of the foams were compared with those predicted by the theoretical model.

Tailored ramp-loading via shock release of stepped-density reservoirs

International Nuclear Information System (INIS)

Prisbrey, Shon T.; Park, Hye-Sook; Remington, Bruce A.; Cavallo, Robert; May, Mark; Pollaine, Stephen M.; Rudd, Robert; Maddox, Brian; Comley, Andrew; Fried, Larry; Blobaum, Kerri; Wallace, Russ; Wilson, Mike; Swift, David; Satcher, Joe; Kalantar, Dan; Perry, Ted; Giraldez, Emilio; Farrell, Michael; Nikroo, Abbas

2012-01-01

The concept of a gradient piston drive has been extended from that of a single component reservoir, such as a high explosive, to that of a multi-component reservoir that utilizes low density foams and large shocks to achieve high pressures (∼3.5 mbar) and controlled pressure vs. time profiles on a driven sample. Simulated and experimental drives shaped through the use of multiple component (including carbonized resorcinol formaldehyde and SiO 2 foam) reservoirs are compared. Individual density layers in a multiple component reservoir are shown to correlate with velocity features in the measured drive which enables the ability to tune a pressure drive by adjusting the components of the reservoir. Pre-shot simulations are shown to be in rough agreement with the data, but post-shot simulations involving the use of simulated plasma drives were needed to achieve an exact match. Results from a multiple component reservoir shot (∼3.5 mbar) at the National Ignition Facility are shown.

Structural applications of metal foams considering material and geometrical uncertainty

Science.gov (United States)

Moradi, Mohammadreza

the composite tube, including the sensitivity of the strength to input parameters such as the foam density, tube wall thickness, steel properties etc. Monte Carlo simulation is performed on aluminum foam filled tubes under three point bending conditions. The simulation method is nonlinear finite element analysis. Results show that the steel foam properties have a greater effect on ductility of the steel foam filled tube than its strength. Moreover, flexural strength is more sensitive to steel properties than to aluminum foam properties. Finally, the properties of hypothetical structural steel foam C-channels foamed are investigated via simulations. In thin-walled structural members, stability of the walls is the primary driver of structural limit states. Moreover, having a light weight is one of the main advantages of the thin-walled structural members. Therefore, thin-walled structural members made of steel foam exhibit improved strength while maintaining their low weight. Linear eigenvalue, finite strip method (FSM) and plastic collapse FE analysis is used to evaluate the strength and ductility of steel foam C-channels under uniform compression and bending. It is found that replacing steel walls of the C-channel with steel foam walls increases the local buckling resistance and decreases the global buckling resistance of the C-channel. By using the Sobol' decomposition, an optimum configuration for the variable density steel foam C-channel can be found. For high relative density, replacing solid steel of the lips and flange elements with steel foam increases the buckling strength. On the other hand, for low relative density replacing solid steel of the lips and flange elements with steel foam deceases the buckling strength. Moreover, it is shown that buckling strength of the steel foam C-channel is sensitive to the second order Sobol' indices. In summary, it is shown in this research that the metal foams have a great potential to improve different types of structural

Structural Foams of Biobased Isosorbide-Containing Copolycarbonate

Directory of Open Access Journals (Sweden)

Stefan Zepnik

2017-01-01

Full Text Available Isosorbide-containing copolycarbonate (Bio-PC is a partly biobased alternative to conventional bisphenol A (BPA based polycarbonate (PC. Conventional PC is widely used in polymer processing technologies including thermoplastic foaming such as foam injection molding. At present, no detailed data is available concerning the foam injection molding behavior and foam properties of Bio-PC. This contribution provides first results on injection-molded foams based on isosorbide-containing PC. The structural foams were produced by using an endothermic chemical blowing agent (CBA masterbatch and the low pressure foam injection molding method. The influence of weight reduction and blowing agent concentration on general foam properties such as density, morphology, and mechanical properties was studied. The test specimens consist of a foam core in the center and compact symmetrical shell layers on the sides. The thickness of the foam core increases with increasing weight reduction irrespective of the CBA concentration. The specific (mechanical bending properties are significantly improved and the specific tensile properties can almost be maintained while reducing the density of the injection-molded parts.

Analysis of syntactic foam – GFRP sandwich composites for flexural loads

Science.gov (United States)

Paul, Daniel; Velmurugan, R.; Jayaganthan, R.; Gupta, N. K.; Manzhirov, A. V.

2018-04-01

The use of glass microballoon (GMB) — epoxy syntactic foams as a sandwich core material is studied. The skins and foam core are fabricated and joined instantaneously unlike the procedures followed in the previous studies. Each successive layer of the sandwich is fabricated when the previous layer is in a semi-gelled state. These sandwich samples are characterized for their properties under flexural loading. The failure modes and mechanical properties are carefully investigated. The change in fabrication technique results in a significant increase in the load bearing pattern of the sandwich. In earlier studies, debonding was found to occur prematurely since the bonding between the skins and core is the weakest plane. Using the current technique, core cracking occurs first, followed by skin fiber breaking and debonding happens at the end. This ensures that the load carrying phase of the structure is extended considerably. The sandwich is also analytically studied using Reddy’s higher order shear deformation theory. A higher order theory is selected as the sandwich can no longer be considered as a thin beam and thus shear effects also need to be considered in addition to bending effects.

Supercritical CO2 foaming of radiation crosslinked polypropylene/high-density polyethylene blend: Cell structure and tensile property

Science.gov (United States)

Yang, Chenguang; Xing, Zhe; Zhang, Mingxing; Zhao, Quan; Wang, Mouhua; Wu, Guozhong

2017-12-01

A blend of isotactic polypropylene (PP) with high-density polyethylene (HDPE) in different PP/HDPE ratios was irradiated by γ-ray to induce cross-linking and then foamed using supercritical carbon dioxide (scCO2) as a blowing agent. Radiation effect on the melting point and crystallinity were analyzed in detail. The average cell diameter and cell density were compared for PP/HDPE foams prepared under different conditions. The optimum absorbed dose for the scCO2 foaming of PP/HDPE in terms of foaming ability and cell structure was 20 kGy. Tensile measurements showed that the elongation at break and tensile strength at break of the crosslinked PP/HDPE foams were higher than the non-crosslinked ones. Of particular interest was the increase in the foaming temperature window from 4 ℃ for pristine PP to 8-12 ℃ for the radiation crosslinked PP/HDPE blends. This implies much easier handling of scCO2 foaming of crosslinked PP with the addition of HDPE.

Influence of polypropylene fibres on the tensile strength and thermal properties of various densities of foamed concrete

Science.gov (United States)

Jhatial, Ashfaque Ahmed; Inn, Goh Wan; Mohamad, Noridah; Johnson Alengaram, U.; Mo, Kim Hung; Abdullah, Redzuan

2017-11-01

As almost half of the world’s population now lives in the urban areas, the raise in temperature in these areas has necessitated the development of thermal insulating material. Conventional concrete absorbs solar radiation during the daytime while releasing it at night causing raise in temperature in urban areas. The thermal conductivity of 2200 kg/m3 density conventional concrete is 1.6 W/mK. Higher the thermal conductivity value, greater the heat flow through the material. To reduce this heat transfer, the construction industry has turned to lightweight foamed concrete. Foamed concrete, due to its air voids, gives excellent thermal properties and sound absorption apart from fire-resistance and self-leveling properties. But due to limited studies on different densities of foamed concrete, the thermal properties are not understood properly thus limiting its use as thermal insulating material. In this study, thermal conductivity is determined for 1400, 1600 and 1800 kg/m3 densities of foamed concrete. 0.8% of Polypropylene fibres (PP) is used to reinforce the foamed concrete and improve the mechanical properties. Based upon the results, it was found that addition of PP fibres enhances the tensile strength and slightly reduced the thermal conductivity for lower densities, while the reverse affect was noticed in 1800 kg/m3 density.

Foam shell project: Progress report

International Nuclear Information System (INIS)

Overturf, G.; Reibold, B.; Cook, B.; Schroen-Carey, D.

1994-01-01

The authors report on their work to produce a foam shell target for two possible applications: (1) as liquid-layered cryogenic target on Omega Upgrade, and (2) as a back-up design for the NIF. This target consists of a roughly 1 mm diameter and 100 μm thick spherical low-density foam shell surrounding a central void. The foam will be slightly overfilled with liquid D 2 or DT, the overfilled excess being symmetrically distributed on the inside of the shell and supported by thermal gradient techniques. The outside of the foam is overcoated with full density polymer which must be topologically smooth. The technology for manufacturing this style of foam shell involves microencapsulation techniques and has been developed by the Japanese at ILE. Their goal is to determine whether this technology can be successfully adapted to meet US ICF objectives. To this end a program of foam shell development has been initiated at LLNL in collaboration with both the General Atomics DOE Target Fabrication Contract Corporation and the Target Fabrication Group at LLE

Preparation and properties of polymer foams for ICF targets

International Nuclear Information System (INIS)

Letts, S.A.; Lucht, L.M.

1986-09-01

Low density small cell sized foams were developed to localize the liquid DT layer in a direct drive wetted foam laser fusion target. We have developed foams made from ultrahigh molecular weight polyethylene gels and polystyrene inverse emulsions. Materials in the density range of from 0.020 to 0.300 g/cc were prepared and characterized for cell size, mechanical properties, machinability, specific surface area, and wetting. Foams with a density of 0.05 g/cc were made with a cell size of less than 5 μm. A cell structure model was developed which relates the density and specific surface area to cell size and cell wall thickness. Wetting tests in organic solvents and in liquid hydrogen were used to characterize the capillary pressure, pore structure and uniformity of the foams. 13 refs., 9 figs., 2 tabs

Mechanical Characterization of Lightweight Foamed Concrete

Directory of Open Access Journals (Sweden)

Marcin Kozłowski

2018-01-01

Full Text Available Foamed concrete shows excellent physical characteristics such as low self weight, relatively high strength and superb thermal and acoustic insulation properties. It allows for minimal consumption of aggregate, and by replacement of a part of cement by fly ash, it contributes to the waste utilization principles. For many years, the application of foamed concrete has been limited to backfill of retaining walls, insulation of foundations and roof tiles sound insulation. However, during the last few years, foamed concrete has become a promising material for structural purposes. A series of tests was carried out to examine mechanical properties of foamed concrete mixes without fly ash and with fly ash content. In addition, the influence of 25 cycles of freezing and thawing on the compressive strength was investigated. The apparent density of hardened foamed concrete is strongly correlated with the foam content in the mix. An increase of the density of foamed concrete results in a decrease of flexural strength. For the same densities, the compressive strength obtained for mixes containing fly ash is approximately 20% lower in comparison to the specimens without fly ash. Specimens subjected to 25 freeze-thaw cycles show approximately 15% lower compressive strengths compared to the untreated specimens.

Three-Dimensional Graphene Foam-Polymer Composite with Superior Deicing Efficiency and Strength.

Science.gov (United States)

Bustillos, Jenniffer; Zhang, Cheng; Boesl, Benjamin; Agarwal, Arvind

2018-02-07

The adhesion of ice severely compromises the aerodynamic performance of aircrafts operating under critically low-temperature conditions to their surfaces. In this study, highly thermally and electrically conductive graphene foam (GrF) polymer composite is fabricated. GrF-polydimethylsiloxane (PDMS) deicing composite exhibits superior deicing efficiency of 477% and electrical conductivities of 500 S m -1 with only 0.1 vol % graphene foam addition as compared to other nanocarbon-based deicing systems. The three-dimensional interconnected architecture of GrF allows the effective deicing of surfaces by employing low power densities (0.2 W cm -2 ). Electrothermal stability of the GrF-PDMS composite was proven after enduring 100 cycles of the dc loading-unloading current. Moreover, multifunctional GrF-PDMS deicing composite provides simultaneous mechanical reinforcement by the effective transfer and absorption of loads resulting in a 23% and 18% increase in elastic modulus and tensile strength, respectively, as compared to pure PDMS. The enhanced efficiency of the GrF-PDMS deicing composite is a novel alternative to current high-power consumption deicing systems.

Reducing wall plasma expansion with gold foam irradiated by laser

International Nuclear Information System (INIS)

Zhang, Lu; Ding, Yongkun; Jiang, Shaoen; Yang, Jiamin; Li, Hang; Kuang, Longyu; Lin, Zhiwei; Jing, Longfei; Li, Liling; Deng, Bo; Yuan, Zheng; Chen, Tao; Yuan, Guanghui; Tan, Xiulan; Li, Ping

2015-01-01

The experimental study on the expanding plasma movement of low-density gold foam (∼1% solid density) irradiated by a high power laser is reported in this paper. Experiments were conducted using the SG-III prototype laser. Compared to solid gold with 19.3 g/cc density, the velocities of X-ray emission fronts moving off the wall are much smaller for gold foam with 0.3 g/cc density. Theoretical analysis and MULTI 1D simulation results also show less plasma blow-off, and that the density contour movement velocities of gold foam are smaller than those of solid gold, agreeing with experimental results. These results indicate that foam walls have advantages in symmetry control and lowering plasma fill when used in ignition hohlraum

Reducing wall plasma expansion with gold foam irradiated by laser

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lu; Ding, Yongkun, E-mail: ding-yk@vip.sina.com; Jiang, Shaoen, E-mail: jiangshn@vip.sina.com; Yang, Jiamin; Li, Hang; Kuang, Longyu; Lin, Zhiwei; Jing, Longfei; Li, Liling; Deng, Bo; Yuan, Zheng; Chen, Tao; Yuan, Guanghui; Tan, Xiulan; Li, Ping [Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-986, Mianyang 621900 (China)

2015-11-15

The experimental study on the expanding plasma movement of low-density gold foam (∼1% solid density) irradiated by a high power laser is reported in this paper. Experiments were conducted using the SG-III prototype laser. Compared to solid gold with 19.3 g/cc density, the velocities of X-ray emission fronts moving off the wall are much smaller for gold foam with 0.3 g/cc density. Theoretical analysis and MULTI 1D simulation results also show less plasma blow-off, and that the density contour movement velocities of gold foam are smaller than those of solid gold, agreeing with experimental results. These results indicate that foam walls have advantages in symmetry control and lowering plasma fill when used in ignition hohlraum.

Effectiveness of Flame Retardants in TufFoam.

Energy Technology Data Exchange (ETDEWEB)

Abelow, Alexis Elizabeth [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Nissen, April [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Massey, Lee Taylor [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Whinnery, LeRoy L. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2017-12-01

An investigation of polyurethane foam filled with known flame retardant fillers including hydroxides, melamine, phosphate-containing compounds, and melamine phosphates was carried out to produce a low-cost material with high flame retardant efficiency. The impact of flame retardant fillers on the physical properties such a s composite foam density, glass transition temperature, storage modulus, and thermal expansion of composite foams was investigated with the goal of synthesizing a robust rigid foam with excellent flame retardant properties.

Effect of Rigid Polyurethane Foam Core Density on Flexural and Compressive Properties of Sandwich Panels with Glass/Epoxy Faces

Directory of Open Access Journals (Sweden)

saeed Nemati

2013-01-01

Full Text Available Sandwich panels as composite materials have two external walls of either metallic or polymer type. The space between these walls is filled by hard foam or other materials and the thickness of different layers is based on the final application of the panel. In the present work, the extent of variation in core density of polyether urethane foam and subsequent flexural and compressive changes in sandwich panels with glass or epoxy face sheets are tested and investigated. A number of hard polyether urethane foams with different middle panel layers density 80-295 kg/m3 are designed to study the effect of foam density on mechanical properties including flexural and compressive properties. Flexural and compressive test resultsshow that increased core density leads to improved mechanical properties. The slope of the curve decreases beyond density of 235 kg/m3. The reason may be explained on the limitation of shear intensity in increasing the mechanical properties. In this respect an optimum density of 235 kg/m3 is obtained for the system under examinations and for reaching higher strength panels, foams of different core materials should be selected.

THE HYDROLOGIC CYCLE, UNIDIRECTIONAL CHARTER OF THE DISSOLVED SALTS AND SUSPENDED LOAD

Directory of Open Access Journals (Sweden)

Nicolae Florea

2012-12-01

Full Text Available In this paper it is underlined that the hydrologic cycle in nature, reversible and regenerating of fresh water, carries out also an unidirectional and irreversible circulation – by means of a fragment of the hydrologic cycle – of the dissolved salts and stream’s suspended load, entailed by the water drained from continents to ocean. The trend is to transfer soluble salts from land to ocean in the same time with the running water on land in the portion of the hydrologic cycle which refers to the water transfer from continents to ocean in order to equilibrate the annual water balance of the hydrologic cycle. But, one can realize here and there some local salt accumulations in salt soils or in salt lakes within areas without drainage in arid climate; these salts accumulations are cases of local hydrologic cycles „grafted” along the way of water on land (to ocean. The energy necessary to the hydrologic cycle in nature is delivered by the Sun, and the entropy remains at a low level as a consequence of the elimination in this cycle of water vapors with high entropy, and of the receiving of liquid or solid water with low entropy, so that the annual level of entropy is maintained at a low level.

A low-cost density reference phantom for computed tomography

OpenAIRE

Levine, Zachary H.; Li, Mingdong; Reeves, Anthony P.; Yankelevitz, David F.; Chen, Joseph J.; Siegel, Eliot L.; Peskin, Adele; Zeiger, Diana N.

2009-01-01

The authors characterized a commercially available foam composed of polyurethane and polyisocyanurate which is marketed for modeling parts in the aircraft, automotive, and related industries. The authors found that the foam may be suitable for use as a density reference standard in the range below −400 Hounsfield units. This range is coincident with the density of lung tissue. The foam may be helpful in making the diagnosis of lung disease more systematic.

A low-cost density reference phantom for computed tomography.

Science.gov (United States)

Levine, Zachary H; Li, Mingdong; Reeves, Anthony P; Yankelevitz, David F; Chen, Joseph J; Siegel, Eliot L; Peskin, Adele; Zeiger, Diana N

2009-02-01

The authors characterized a commercially available foam composed of polyurethane and polyisocyanurate which is marketed for modeling parts in the aircraft, automotive, and related industries. The authors found that the foam may be suitable for use as a density reference standard in the range below -400 Hounsfield units. This range is coincident with the density of lung tissue. The foam may be helpful in making the diagnosis of lung disease more systematic.

Evaluation of Canisterized Foams and Evaluation of Radiation Hardened Foams for D&D Activities

Energy Technology Data Exchange (ETDEWEB)

Nicholson, J. C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-09-26

The introduction of polyurethane foams has previously been examined elsewhere within the DOE complex with regards to decontamination and decommissioning (D&D) activities, though its use has been prohibited as a result of excessive heat generation and flammability concerns per the safety basis. Should these foams be found compatible with respect to the facility safety basis requirements, D&D work involving large void containing structures such as gloveboxes could be eased through the fixation of residual contamination after decontamination efforts have concluded. To this end, SRNL embarked on a characterization of commercial epoxy foams to identify the characteristics that would be most important to safety basis requirements. Through SRNL’s efforts, the performance of commercial two-part epoxy foams was evaluated for their foaming characteristics, temperature profiles, loading capability with high-Z (high density) additives, and applicability for shielding gamma emission from isotopes including; Am-241, Cs-137, and Co-60. It was found that these foams are capable of encapsulation of a desired volume, though the ideal and experimental expansion coefficients were found to differ. While heat is generated during the reaction, no samples generated heat above 70 °C. Of the down–selected materials, heating was on the order of 40 °C for the flexible foam and 60 °C for the rigid foam. Both were found to return to room temperature after 20 minutes regardless of the volume of foam cast. It was also found that the direct introduction of high-Z additives were capable of attenuating 98% of Am-241 gamma signal, 16% of Cs-137 signal, and 9.5% of Co-60 signal at 1:1 loading capacities of total liquid constituent weight to additive weight. These efforts are currently being reviewed for the ASTM January 2017 subcommittee discussions to address the lack of test methods and standards regarding these materials with respect to D&D environments.

Deformation and energy absorption properties of powder-metallurgy produced Al foams

International Nuclear Information System (INIS)

Michailidis, N.; Stergioudi, F.; Tsouknidas, A.

2011-01-01

Highlights: → Porous Al fabricated via a dissolution and sintering method using raw cane sugar. → Different deformation mode depending on the relative density of the foams. → Enhanced energy absorption by reducing pore size and relative density of the foam. → Pore size uniformity and sintering temperature affect energy absorption. - Abstract: Al-foams with relative densities ranging from 0.30 to 0.60 and mean pore sizes of 0.35, 0.70 and 1.35 mm were manufactured by a powder metallurgy technology, based on raw cane sugar as a space-holder material. Compressive tests were carried out to investigate the deformation and energy absorbing characteristics and mechanisms of the produced Al-foams. The deformation mode of low density Al-foams is dominated by the bending and buckling of cell walls and the formation of macroscopic deformation bands whereas that of high density Al-foams is predominantly attributed to plastic yielding. The energy absorbing capacity of Al-foams rises for increased relative density and compressive strength. The sintering temperature of Al-foams having similar relative densities has a marked influence on both, energy absorbing efficiency and capacity. Pore size has a marginal effect on energy efficiency aside from Al-foams with mean pore size of 0.35 which exhibit enhanced energy absorption as a result of increased friction during deformation at lower strain levels.

Manufacturing and Characterization of Temperature-Stable, Novel, Viscoelastic Polyurea Based Foams for Impact Management

Science.gov (United States)

Ramirez, Brian Josue

The aim of this thesis was to develop advance, high performance polyurea foams for multi-hit capability in protective equipment that respond over a range of impact energies, temperatures, and strain rates. In addition, the microstructure of these materials should be tunable such that the peak stress (or force) transmitted across the foam section can be limited to a specific value defined by an injury threshold while maximizing impact energy absorption. Novel polyurea foams were manufactured and found to exhibit a reversible viscoelastic shear deformation at the molecular level. The intrinsic shear dissipation process is synergistically coupled to controlled collapse of a novel pore structure. The microstructure compromises of stochastic polyhedral cells ranging from 200 - 500 mum with perforated membranes with small apertures ( 20 mum). This makes them strain rate sensitive as the rate at which the air escapes the cells depend upon the loading rate. These mechanisms operate simultaneously and sequentially, thereby significantly reducing the transmitted impact forces across the foam section. Thus, they behave as an elastically modulated layered composite because the cells stiffen or soften in response to the changing loading rate. Therefore, the newly developed polyurea foams are able to manage the varying material strain rate that occurs within the same loading event without the need to modulate the stiffness or density. Additionally, polyurea foams were found to retain its excellent impact properties over a range of temperatures (0°C to 40°C) by having a glass transition temperature well below 0°C. This is in contrast to commercially available high performance foams that have the glass transition temperature near 0°C and absorb energy through phase transformation at ambient conditions, but significantly stiffen at lower temperatures, and dramatically soften at higher temperatures. This expands the application domain of polyurea foam material considerably as it

Biodegradable poly (lactic acid)/Cellulose nanocrystals (CNCs) composite microcellular foam: Effect of nanofillers on foam cellular morphology, thermal and wettability behavior.

Science.gov (United States)

Borkotoky, Shasanka Sekhar; Dhar, Prodyut; Katiyar, Vimal

2018-01-01

This article addresses the elegant and green approach for fabrication of bio-based poly (lactic acid) (PLA)/cellulose nanocrystal (CNCs) bionanocomposite foam (PLA/CNC) with cellular morphology and hydrophobic surface behavior. Highly porous (porosity >80%) structure is obtained with interconnected pores and the effect of CNCs in the cell density (N f ) and cell size of foams are thoroughly investigated by morphological analysis. The thermo-mechanical investigations are performed for the foam samples and almost ∼1.7 and ∼2.2 fold increase in storage modulus is observed for the compressive and tensile mode respectively. PLA/CNC based bionanocomposite foams displayed similar thermal stability as base PLA foam. Detailed investigations of decomposition behavior are studied by using hyphenated thermogravimetric analysis-fourier transmission infrared spectroscopy (TGA-FTIR) system. Almost ∼13% increment is observed in crystallinity at highest loading of CNCs compared to neat counterpart. To investigate the splitting and spreading phenomenon of the wettability of the samples, linear model is used to find the Young's contact angle and contact angle hysteresis (CAH). Besides, ∼6.1 folds reduction in the density of PLA and the nanocomposite foams compared to PLA carries much significance in specialized application areas where weight is an important concern. Copyright © 2017 Elsevier B.V. All rights reserved.

Equipment evaluation for low density polyethylene encapsulated nitrate salt waste at the Rocky Flats Plant

International Nuclear Information System (INIS)

Yamada, W.I.; Faucette, A.M.; Jantzen, R.C.; Logsdon, B.W.; Oldham, J.H.; Saiki, D.M.; Yudnich, R.J.

1993-01-01

Mixed wastes at the Rocky Flats Plant (RFP) are subject to regulation by the Resource Conservation and Recovery Act (RCRA). Polymer solidification is being developed as a final treatment technology for several of these mixed wastes, including nitrate salts. Encapsulation nitrate salts with low density polyethylene (LDPE) has been the preliminary focus of the RFP polymer solidification effort. Literature reviews, industry surveys, and lab-scale and pilot-scale tests have been conducted to evaluate several options for encapsulating nitrate salts with LDPE. Most of the effort has focused on identifying compatible drying and extrusion technologies. Other processing options, specifically meltration and non-heated compounding machines, were also investigated. The best approach appears to be pretreatment of the nitrate salt waste brine in either a vertical or horizontal thin film evaporator followed by compounding of the dried waste with LDPE in an intermeshing, co-rotating, twin-screw extruder. Additional pilot-scale tests planned for the fall of 1993 should further support this recommendation. Preliminary evaluation work indicates that meltration is not possible at atmospheric pressure with the LDPE (Chevron PE-1409) provided by RFP. However, meltration should be possible at atmospheric pressure using another LDPE formulation with altered physical and rheological properties: Lower molecular weight and lower viscosity (Epoline C-15). Contract modifications are now in process to allow a follow-on pilot scale demonstration. Questions regarding changed safety and physical properties of the resultant LDPE waste form due to use of the Epoline C-15 will be addressed. No additional work with non-heated mixer compounder machines is planned at this time

Filling material for a buried cavity in a collapse area using light-weighted foam and active feldspar

Science.gov (United States)

Cho, Jin Woo; Lee, Ju-hyoung; Kim, Sung-Wook; Choi, Eun-Kyeong

2017-04-01

Concrete which is generally used as filling material for a buried cavity has very high strength but significantly high self-load is considered its disadvantage. If it is used as filling material, the second collapse due to additional load, causing irreversible damage. If light-weighted foam and active feldspar are used to solve this problem, the second collapse can be prevented by reducing of self-load of filling material. In this study, the specimen was produced by mixing light-weighted foam, active feldspar and cement, and changes in the density, unconfined compressive strength and hydraulic conductivity were analyzed. Using the light-weighted foam could enable the adjustment of density of specimen between 0.5 g/cm3 and 1.7 g/cm3, and if the mixing ratio of the light-weighted foam increases, the specimen has more pores and smaller range of cross-sectional area. It is confirmed that it has direct correlation with the density, and if the specimen has more pores, the density of the specimen is lowered. The density of the specimen influences the unconfined compressive strength and the hydraulic conductivity, and it was also confirmed that the unconfined compressive strength could be adjusted between 0.6 MPa and 8 MPa and the hydraulic conductivity could be adjusted between 10-9cm/sec and 10-3cm/sec. These results indicated that we can adjust unconfined compressive strength and hydraulic conductivity of filling materials by changing the mixing amount of lightweight-weighted foam according to the requirements of the field condition. Keywords: filling material, buried cavity, light-weighted foam, feldspar Acknowledgement This research was supported by a Grant from a Strategic Research Project (Horizontal Drilling and Stabilization Technologies for Urban Search and Rescue (US&R) Operation) funded by the Korea Institute of Civil Engineering and Building Technology.

Foam formation in low expansion fire fighting equipment

International Nuclear Information System (INIS)

Rogers, Lucy Elizabeth

2001-01-01

This thesis describes an investigation into the foam generation mechanisms involved in producing foam from a low expansion fire fighting branchpipe. The investigation was carried out using scale models of branchpipes, and a high-speed video camera was used to study the formation of the foam. The experiments provided evidence of three possible methods of bubble formation within this type of system: Stage 1 - Mixing within the branchpipe; Stage 2 - Air entrainment and bubble growth during the flight of the jet; Stage 3 - Aeration produced from the collision of the high speed jet onto a surface. Each stage is described in detail and the mechanism which has the greatest effect on the expansion ratio of the foam produced has been determined. The relevance of these findings to the design of branchpipes is discussed. (author)

Optimized Synthesis of Foam Glass from Recycled CRT Panel Glass

DEFF Research Database (Denmark)

Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

Most of the panel glass from cathode ray tubes (CRTs) is landfilled today. Instead of landfilling, the panel glass can be turned into new environment-friendly foam glass. Low density foam glass is an effective heat insulating material and can be produced just by using recycle glass and foaming...... additives. In this work we recycle the CRT panel glass to synthesize the foam glass as a crucial component of building and insulating materials. The synthesis conditions such as foaming temperature, duration, glass particle size, type and concentrations of foaming agents, and so on are optimized...... by performing systematic experiments. In particular, the concentration of foaming agents is an important parameter that influences the size of bubbles and the distribution of bubbles throughout the sample. The foam glasses are characterised regarding density and open/closed porosity. Differential scanning...

Finite Element Analysis and Crashworthiness Optimization of Foam-filled Double Circular under Oblique Loading

Directory of Open Access Journals (Sweden)

Fauzan Djamaluddin

Full Text Available Abstract Finite element analysis and optimization design carry out for the quasi static responses of foam-filled double circular tube is presented in this paper. In the investigation of the crashworthiness capability, some aspects were considered for variations in geometry parameters of tubes and the loading condition to investigate the crashworthiness capability. Empty, foam-filled, and full foam-filled doublé tubes of thin walled structures were observed subjected to oblique impact (0˚ - 40˚. The numerical solution was used to determine the crashworthiness parameters. In addition, NSGA II and Radial Basis Function were used to optimize the crashworthiness capability of tubes. In conclution, the crash performaces of foam-filled double tube is better than the other structures in this work. The outcome that expected is the new design information of various kinds of cylindrical tubes for energy absorber application.

Objectification of Modulus Elasticity of Foam Concrete Poroflow 17-5 on the Subbase Layer

Directory of Open Access Journals (Sweden)

Hájek Matej

2016-05-01

Full Text Available Principles of sustainable development create the need to develop new building materials. Foam concrete is a type of lightweight concrete that has many advantages compared to conventional building materials, for example low density and thermal insulation characteristics. With current development level, any negatively influencing material features are constantly eliminated as well. This paper is dealing with substitution of hydraulically bound mixtures by cement foam concrete Poroflow 17-5. The executed assessment is according to the methodology of assessing the existing asphalt pavements in Slovak Republic. The ex post calculation was used to estimate modulus range for Poroflow 17-5 based on the results of static load tests conducted using the Testing Experiment Equipment.

Effect of gas type on foam film permeability and its implications for foam flow in porous media.

Science.gov (United States)

Farajzadeh, R; Muruganathan, R M; Rossen, W R; Krastev, R

2011-10-14

The aim of this paper is to provide a perspective on the effect of gas type on the permeability of foam films stabilized by different types of surfactant and to present a critical overview of the tracer gas experiments, which is the common approach to determine the trapped fraction of foam in porous media. In these experiments some part of the gas is replaced by a "tracer gas" during the steady-state stage of the experiments and trapped fraction of foam is determined by fitting the effluent data to a capacitance mass-transfer model. We present the experimental results on the measurement of the gas permeability of foam films stabilized with five surfactants (non-ionic, anionic and cationic) and different salt concentrations. The salt concentrations assure formation of either common black (CBF) or Newton black films (NBF). The experiments are performed with different single gasses. The permeability of the CBF is in general higher than that of the NBF. This behavior is explained by the higher density of the surfactant molecules in the NBF compared to that of CBF. It is also observed that the permeability coefficient, K(cm/s), of CBF and NBF for non-ionic and cationic surfactants are similar and K is insensitive to film thickness. Compared to anionic surfactants, the films made by the non-ionic surfactant have much lower permeability while the films made by the cationic surfactant have larger permeability. This conclusion is valid for all gasses. For all types of surfactant the gas permeability of foam film is largely dependent on the dissolution of gas in the surfactant solution and increases with increasing gas solubility in the bulk liquid. The measured values of K are consistent with rapid diffusion of tracer gasses through trapped gas adjacent to flowing gas in porous media, and difficulties in interpreting the results of tracer-foam experiments with conventional capacitance models. The implications of the results for foam flow in porous media and factors leading

Effect of Pelletized Coconut Fibre on the Compressive Strength of Foamed Concrete

Directory of Open Access Journals (Sweden)

Mohd Jaini Zainorizuan

2016-01-01

Full Text Available Foamed concrete is a controlled low density ranging from 400kg/m3 to 1800kg/m3, and hence suitable for the construction of buildings and infrastructures. The uniqueness of foamed concrete is does not use aggregates in order to retain low density. Foamed concrete contains only cement, sand, water and foam agent. Therefore, the consumption of cement is higher in producing a good quality and strength of foamed concrete. Without the present of aggregates, the compressive strength of foamed concrete can only achieve as high as 15MPa. Therefore, this study aims to introduce the pelletized coconut fibre aggregate to reduce the consumption of cement but able to enhance the compressive strength. In the experimental study, forty-five (45 cube samples of foamed concrete with density 1600kg/m3 were prepared with different volume fractions of pelletized coconut fibre aggregate. All cube samples were tested using the compression test to obtain compressive strength. The results showed that the compressive strength of foamed concrete containing 5%, 10%, 15% and 20% of pelletized coconut fibre aggregate are 9.6MPa, 11.4MPa, 14.6MPa and 13.4MPa respectively. It is in fact higher than the controlled foamed concrete that only achieves 9MPa. It is found that the pelletized coconut fibre aggregate indicates a good potential to enhance the compressive strength of foamed concrete.

Effects of nitrogen loading on greenhouse gas emissions in salt marshes

Science.gov (United States)

Tang, J.; Moseman-Valtierra, S.; Kroeger, K. D.; Morkeski, K.; Mora, J.; Chen, X.; Carey, J.

2014-12-01

Salt marshes play an important role in global and regional carbon and nitrogen cycling. We tested the hypothesis that anthropogenic nitrogen loading alters greenhouse gas (GHG, including CO2, CH4, and N2O) emissions and carbon sequestration in salt marshes. We measured GHG emissions biweekly for two growing seasons across a nitrogen-loading gradient of four Spartina salt marshes in Waquoit Bay, Massachusetts. In addition, we conducted nitrogen addition experiments in a pristine marsh by adding low and high nitrate to triplicate plots bi-weekly during the summer. The GHG flux measurements were made in situ with a state-of-the-art mobile gas measurement system using the cavity ring down technology that consists of a CO2/CH4 analyzer (Picarro) and an N2O/CO analyzer (Los Gatos). We observed strong seasonal variations in greenhouse gas emissions. The differences in gas emissions across the nitrogen gradient were not significant, but strong pulse emissions of N2O were observed after nitrogen was artificially added to the marsh. Our results will facilitate model development to simulate GHG emissions in coastal wetlands and support methodology development to assess carbon credits in preserving and restoring coastal wetlands.

Effects of Sb2O3 on the Mechanical Properties of the Borosilicate Foam Glasses Sintered at Low Temperature

Directory of Open Access Journals (Sweden)

Chenxi Zhai

2014-01-01

Full Text Available The physical properties and microstructure of a new kind of borosilicate foam glasses with different Sb2O3 doping content are comprehensively investigated. The experimental results show that appropriate addition of Sb2O3 has positive impact on the bulk porosity and compressive strength of the foam glass. It is more suitable in this work to introduce 0.9 wt.% Sb2O3 into the Na2O-K2O-B2O3-Al2O3-SiO2 basic foam glass component and sinter at 775°C. And the obtained foam glasses present much more uniform microstructure, large pore size, and smooth cell walls, which bring them with better performance including a lower bulk density, low water absorption, and an appreciable compressive strength. The microstructure analysis indicates that, with the increase of the content of Sb2O3 additives, the cell size tends to increase at first and then decreases. Larger amounts of Sb2O3 do not change the crystalline phase of foam glass but increase its vitrification. It is meaningful to prepare the foam glass at a relatively low temperature for reducing the heat energy consumption.

Preparation of multishell ICF target plastic-foam cushion materials by thermally induced phase-inversion processes

International Nuclear Information System (INIS)

Young, A.T.; Moreno, D.K.; Marsters, R.G.

1981-01-01

Homogenous, low-density plastic foams for ICF targets have been prepared by thermally induced phase inversion processes. Uniform, open cell foams have been obtained by the rapid freezing of water solutions of modified cellulose polymers with densities in the range of 5 mg/cm 3 to 0.7 mg/cm 3 and respective average cell sizes of 2 to 40 micrometers. In addition, low-density, microcellular foams have been prepared from the hydrocarbon polymer poly(4-methyl-l-pentene) via a similar phase inversion process using homogenous solutions in organic solvents. These foams have densities from 2 to 5 mg/cm 3 and average cell sizes of 20 micrometers. The physical-chemical aspects of the thermally induced phase inversion process is presented

Fabrication of Foam Shells for ICF Experiments

Science.gov (United States)

Czechowicz, D. G.; Acenas, O.; Flowers, J. S.; Nikroo, A.; Paguio, R. R.; Schroen, D. G.; Streit, J.; Takagi, M.

2004-11-01

The General Atomics/Schafer team has developed processes to fabricate foam shells targets suitable for ICF experiments. The two most common chemical systems used to produce foam shells have been resorcinol-formaldehyde (R/F) aerogel and divinylbenzene (DVB). Spherical targets have been made in the form of shells and beads having diameters ranging from approximately 0.5 mm to 4.0 mm, and having densities from approximately 100 mg/cc to 250 mg/cc. The work on R/F foam shells has been concentrated on 1) shell fabrication process improvement to obtain high yields ( ˜25%) and 2) depositing a reliable permeation barrier to provide shells for ongoing direct drive experiments at LLE. Development of divinylbenzene foam shells has been mainly directed towards Inertial Fusion Energy applications (at densities as low as 30 mg/cc) and recently for shells for experiments at LLE. Details of the relevant metrology and properties of these foams as well as the range of targets currently available will be discussed.

Three-dimensional printing and deformation behavior of low-density target structures by two-photon polymerization

Science.gov (United States)

Liu, Ying; Stein, Ori; Campbell, John H.; Jiang, Lijia; Petta, Nicole; Lu, Yongfeng

2017-08-01

Two-photon polymerization (2PP), a 3D nano to microscale additive manufacturing process, is being used for the first time to fabricate small custom experimental packages ("targets") to support laser-driven high-energy-density (HED) physics research. Of particular interest is the use of 2PP to deterministically print low-density, low atomic-number (CHO) polymer matrices ("foams") at millimeter scale with sub-micrometer resolution. Deformation during development and drying of the foam structures remains a challenge when using certain commercial photo-resins; here we compare use of acrylic resins IP-S and IP-Dip. The mechanical strength of polymeric beam and foam structures is examined particularly the degree of deformation that occurs during the development and drying processes. The magnitude of the shrinkage in the two resins in quantified by printing sample structures and by use of FEA to simulate the deformation. Capillary drying forces are shown to be small and likely below the elastic limit of the core foam structure. In contrast the substantial shrinkage in IP-Dip ( 5-10%) cause large shear stresses and associated plastic deformation particularly near constrained boundaries such as the substrate and locations with sharp density variation. The inherent weakness of stitching boundaries is also evident and in certain cases can lead to delamination. Use of IP-S shows marked reduction in deformation with a minor loss of print resolution

Copper ferrocyanide - polyurethane foam as a composite ion exchanger for removal of radioactive cesium

International Nuclear Information System (INIS)

Rao, S.V.S.; Lal, K.B.; Ahmed, J.; Narasimhan, S.V.

1999-01-01

A method has been developed for the removal of cesium from the aqueous radioactive waste using a composite ion-exchanger consisting of Copper-Ferrocyanide Powder (CFC) and Polyurethane (PU) Foam. Polyvinyl acetate has been used as a binder in the preparation of CFC-PU foam. The physical properties of CFC such as density, surface area, IR stretching frequency and lattice parameters have been evaluated and also its potassium and copper(II) content have been estimated. Optimization of loading of CFC on PU foam has been studied. The CFC-PU was viewed under microscope to find out the homogeneity of distribution. Exchange capacities of the CFC-PU foam in different media have been determined and column studies have been carried out. Studies have been undertaken on extraction of cesium from CFC foam and also on digestion of spent CFC-PU foam and immobilization of digested solution in cement matrix. The cement matrices have been characterized with respect to density, bio-resistance and leaching resistance. (author)

Experimental study of a foam concrete based on local Tunisian materials

Directory of Open Access Journals (Sweden)

Ellouze Dorra

2018-01-01

Full Text Available The building sector in Tunisia is very energy-intensive, the largest share of energy consumption comes from factories of building materials namely brick and cement plants. This work is part of the reduction of the energy bill in the building envelope. Indeed, the foam concrete can be walls in single or double wall with better insulating power. This paper presents an experimental study on the technical problems related to the formulation and manufacture of a new cellular concrete in Tunisia, called "foam" concrete, from Tunisian local materials. Indeed, six varieties of sand of different provenance and grain size will be analyzed, the "good" sand is the one that is best suited for the manufacture of foam concrete. Two clean, fine-grained (0/2mm rolled grain sands were retained. Then four foam concretes were formulated using each time a single type of sand and varying the density namely 0.8 and 1. These four formulations were tested mechanically and thermally. The results found showed that compressive strengths do not exceed 1.5 MPa at 28 days. Thus, the foam concrete can be used only as a filling concrete in non-load bearing elements such as partition walls. The guarded hot plate method was used to determine the thermal conductivities of the four foamed concretes studied. A low thermal conductivity was found of the order of 0.22 W/m°K which prove the insulating power of foam concrete.

Biological Effect of Gas Plasma Treatment on CO2 Gas Foaming/Salt Leaching Fabricated Porous Polycaprolactone Scaffolds in Bone Tissue Engineering

Directory of Open Access Journals (Sweden)

Tae-Yeong Bak

2014-01-01

Full Text Available Porous polycaprolactone (PCL scaffolds were fabricated by using the CO2 gas foaming/salt leaching process and then PCL scaffolds surface was treated by oxygen or nitrogen gas plasma in order to enhance the cell adhesion, spreading, and proliferation. The PCL and NaCl were mixed in the ratios of 3 : 1. The supercritical CO2 gas foaming process was carried out by solubilizing CO2 within samples at 50°C and 8 MPa for 6 hr and depressurization rate was 0.4 MPa/s. The oxygen or nitrogen plasma treated porous PCL scaffolds were prepared at discharge power 100 W and 10 mTorr for 60 s. The mean pore size of porous PCL scaffolds showed 427.89 μm. The gas plasma treated porous PCL scaffolds surface showed hydrophilic property and the enhanced adhesion and proliferation of MC3T3-E1 cells comparing to untreated porous PCL scaffolds. The PCL scaffolds produced from the gas foaming/salt leaching and plasma surface treatment are suitable for potential applications in bone tissue engineering.

Polystyrene Foam EOS as a Function of Porosity and Fill Gas

Science.gov (United States)

Mulford, Roberta; Swift, Damian

2009-06-01

An accurate EOS for polystyrene foam is necessary for analysis of numerous experiments in shock compression, inertial confinement fusion, and astrophysics. Plastic to gas ratios vary between various samples of foam, according to the density and cell-size of the foam. A matrix of compositions has been investigated, allowing prediction of foam response as a function of the plastic-to-air ratio. The EOS code CHEETAH allows participation of the air in the decomposition reaction of the foam, Differences between air-filled, nitrogen-blown, and CO2-blown foams are investigated, to estimate the importance of allowing air to react with plastic products during decomposition. Results differ somewhat from the conventional EOS, which are generated from values for plastic extrapolated to low densities.

On the implicit density based OpenFOAM solver for turbulent compressible flows

Science.gov (United States)

Fürst, Jiří

The contribution deals with the development of coupled implicit density based solver for compressible flows in the framework of open source package OpenFOAM. However the standard distribution of OpenFOAM contains several ready-made segregated solvers for compressible flows, the performance of those solvers is rather week in the case of transonic flows. Therefore we extend the work of Shen [15] and we develop an implicit semi-coupled solver. The main flow field variables are updated using lower-upper symmetric Gauss-Seidel method (LU-SGS) whereas the turbulence model variables are updated using implicit Euler method.

Surface properties of AZ91 magnesium alloy after PEO treatment using molybdate salts and low current densities

Science.gov (United States)

Pezzato, Luca; Brunelli, Katya; Napolitani, Enrico; Magrini, Maurizio; Dabalà, Manuele

2015-12-01

Plasma electrolytic oxidation (PEO) process is a recently developed electrochemical method used to produce on the surface of various metals oxide ceramic coatings that improve corrosion and wear properties of the substrate. In this work, PEO process was applied on AZ91 magnesium alloy using low current densities (0.05 A/cm2) and an alkaline solution of silicates with different concentrations of sodium molybdate (0.3-3 g/l). The effect of the low current densities of process and of molybdate salts on the corrosion resistance of the coatings was studied with potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) in chloride and sulfate environment. The morphology, the phases and the chemical composition of the coatings were examined using a scanning electron microscope equipped with EDS, X-ray diffraction, secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The corrosion properties of the PEO coated samples were remarkably improved if compared with the uncoated samples. The addition of sodium molybdate, in determinate conditions, had a positive effect on the characteristics of the coatings in terms of corrosion resistance.

Low-salt diet

Science.gov (United States)

Low-sodium diet; Salt restriction ... control many functions. Too much sodium in your diet can be bad for you. For most people, ... you limit salt. Try to eat a balanced diet. Buy fresh vegetables and fruits whenever possible. They ...

Greenhouse gas emissions in salt marshes and their response to nitrogen loading

Science.gov (United States)

Tang, J.; Moseman-Valtierra, S.; Kroeger, K. D.; Morkeski, K.; Carey, J.

2015-12-01

Salt marshes play an important role in global and regional carbon and nitrogen cycling. Anthropogenic nitrogen loading may alter greenhouse gas (GHG, including CO2, CH4, and N2O) emissions and carbon sequestration in salt marshes. We measured GHG emissions biweekly for two growing seasons across a nitrogen-loading gradient of four Spartina salt marshes in Waquoit Bay, Massachusetts. In addition, we conducted nitrogen addition experiments in a pristine marsh by adding low and high nitrate bi-weekly during the summer. The GHG flux measurements were made in situ with a state-of-the-art mobile gas measurement system using the cavity ring down technology that consists of a CO2/CH4 analyzer (Picarro) and an N2O/CO analyzer (Los Gatos). We observed strong seasonal variations in greenhouse gas emissions. The differences in gas emissions across the nitrogen gradient (between 1 and 10 gN m-2y-1) were not significant, but strong pulse emissions of N2O were observed after nitrogen was artificially added to the marsh. We found that the studied salt marsh was a significant carbon sink (NEP ~ 380 gC m-2y-1). CH4 fluxes are 3 orders of magnitude less than CO2 fluxes in the salt marsh. Carbon fluxes are driven by light, salinity, tide, and temperature. We conclude that restoration or conservation of this carbon sink has a significant social benefit for carbon credit.

A finite element/level set model of polyurethane foam expansion and polymerization

Energy Technology Data Exchange (ETDEWEB)

Rao, Rekha R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Long, Kevin Nicholas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roberts, Christine Cardinal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brunini, Victor [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soehnel, Melissa Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Noble, David R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tinsley, James [Honeywell Federal Manufacturing & Technologies, Kansas City, MO (United States); Mondy, Lisa [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-12-01

Polyurethane foams are used widely for encapsulation and structural purposes because they are inexpensive, straightforward to process, amenable to a wide range of density variations (1 lb/ft3 - 50 lb/ft3), and able to fill complex molds quickly and effectively. Computational model of the filling and curing process are needed to reduce defects such as voids, out-of-specification density, density gradients, foam decomposition from high temperatures due to exotherms, and incomplete filling. This paper details the development of a computational fluid dynamics model of a moderate density PMDI structural foam, PMDI-10. PMDI is an isocyanate-based polyurethane foam, which is chemically blown with water. The polyol reacts with isocyanate to produces the polymer. PMDI- 10 is catalyzed giving it a short pot life: it foams and polymerizes to a solid within 5 minutes during normal processing. To achieve a higher density, the foam is over-packed to twice or more of its free rise density of 10 lb/ft3. The goal for modeling is to represent the expansion, filling of molds, and the polymerization of the foam. This will be used to reduce defects, optimize the mold design, troubleshoot the processed, and predict the final foam properties. A homogenized continuum model foaming and curing was developed based on reaction kinetics, documented in a recent paper; it uses a simplified mathematical formalism that decouples these two reactions. The chemo-rheology of PMDI is measured experimentally and fit to a generalized- Newtonian viscosity model that is dependent on the extent of cure, gas fraction, and temperature. The conservation equations, including the equations of motion, an energy balance, and three rate equations are solved via a stabilized finite element method. The equations are combined with a level set method to determine the location of the foam-gas interface as it evolves to fill the mold. Understanding the thermal history and loads on the foam due to exothermicity and oven

Effects of Clofibrate on Salt Loading-Induced Hypertension in Rats

Science.gov (United States)

Cruz, Antonio; Rodríguez-Gómez, Isabel; Pérez-Abud, Rocío; Vargas, Miguel Ángel; Wangensteen, Rosemary; Quesada, Andrés; Osuna, Antonio; Moreno, Juan Manuel

2011-01-01

The effects of clofibrate on the hemodynamic and renal manifestations of increased saline intake were analyzed. Four groups of male Wistar rats were treated for five weeks: control, clofibrate (240 mg/kg/day), salt (2% via drinking water), and salt + clofibrate. Body weight, systolic blood pressure (SBP), and heart rate (HR) were recorded weekly. Finally, SBP, HR, and morphologic, metabolic, plasma, and renal variables were measured. Salt increased SBP, HR, urinary isoprostanes, NOx, ET, vasopressin and proteinuria and reduced plasma free T4 (FT4) and tissue FT4 and FT3 versus control rats. Clofibrate prevented the increase in SBP produced by salt administration, reduced the sodium balance, and further reduced plasma and tissue thyroid hormone levels. However, clofibrate did not modify the relative cardiac mass, NOx, urinary ET, and vasopressin of saline-loaded rats. In conclusion, chronic clofibrate administration prevented the blood pressure elevation of salt-loaded rats by decreasing sodium balance and reducing thyroid hormone levels. PMID:20981147

Review of Thermal Materials for CSP Plants and LCOE Evaluation for Performance Improvement using Chilean Strategic Minerals: Lithium Salts and Copper Foams

Directory of Open Access Journals (Sweden)

Gustavo Cáceres

2016-01-01

Full Text Available The improvement of solar thermal technologies in emerging economies like Chile is particularly attractive because the country is endowed with one of the most consistently high solar potentials, lithium and copper reserves. In recent years, growing interests for lithium based salts and copper foams in application of thermal technologies could change the landscape of Chile transforming its lithium reserves and copper availability into competitive energy produced in the region. This study reviews the technical advantages of using lithium based salts—applied as heat storage media and heat transfer fluid—and copper foam/Phase Change Materials (PCM alternatives—applied as heat storage media—within tower and parabolic trough Concentrated Solar Power (CSP plants, and presents a first systematic evaluation of the costs of these alternatives based on real plant data. The methodology applied is based on material data base compilation of price and technical properties, selection of CSP plant and estimation of amount of required material, and analysis of Levelized Cost of Electricity (LCOE. Results confirm that some lithium based salts are effective in reducing the amount of required material and costs for the Thermal Energy Storage (TES systems for both plant cases, with savings of up to 68% and 4.14% in tons of salts and LCOE, respectively. Copper foam/PCM composites significantly increase thermal conductivity, decreasing the volume of the TES system, but costs of implementation are still higher than traditional options.

Effect of PVA and PDE on selected structural characteristics of extrusion-cooked starch foams

Directory of Open Access Journals (Sweden)

Maciej Combrzyński

2018-03-01

Full Text Available Abstract The aim of this work was to determine selected physical properties of biodegradable thermoplastic starch (TPS filling foams manufactured by extrusion-cooking technique from different combinations of potato starch and two additives: poly(vinyl alcohol PVA and Plastronfoam PDE. Foams were processed with seven starch/additives combinations at two different extruder-cooker’s screw rotational speeds. The densities of starch foams depended significantly on the additive type and content. The linear relationship between the Young modulus and the ultimate compression force and apparent density was found. The foams processed with the addition of PVA had low density, porosity and lower values of the Young modulus than the foams prepared with PDE.

Identification of the Oxidized Low-Density Lipoprotein Scavenger Receptor CD36 in Plasma

DEFF Research Database (Denmark)

Handberg, Aase; Levin, Klaus; Højlund, Kurt

2006-01-01

BACKGROUND: Macrophage CD36 scavenges oxidized low-density lipoprotein, leading to foam cell formation, and appears to be a key proatherogenic molecule. Increased expression of CD36 has been attributed to hyperglycemia and to defective macrophage insulin signaling in insulin resistance. Premature...

Investigation on the effect of formulation and process variables of Polyethylene Foams Production

International Nuclear Information System (INIS)

Barikani, H.; Sarai, M.

2001-01-01

Polyolefin foams such as polyethylene, polypropylene and their copolymers have been extensively used in packaging, automotive, military, marine, cable industries and sports, due to their unique properties namely: light weight, chemical resistance, thermal insulation, inertness, abrasion resistance, buoyancy and low cost. With regards to domestic mass production of polyethylene, replacement of polyurethane with polyethylene foam is very important in some applications from economical point of view. In this research preparation of high density and low density polyethylene foams were studied and the effect of formulation factors such as blowing agent, cross-linker, calcium carbonate, zinc oxide and processing factors such as heat, pressure and reaction time on density and cell size were investigated

Model fire tests on polyphosphazene rubber and polyvinyl chloride (PVC)/nitrile rubber foams

Science.gov (United States)

Widenor, W. M.

1978-01-01

A video tape record of model room fire tests was shown, comparing polyphosphazene (P-N) rubber and polyvinyl chloride (PVC)/nitrile rubber closed-cell foams as interior finish thermal insulation under conditions directly translatable to an actual fire situation. Flashover did not occur with the P-N foam and only moderate amounts of low density smoke were formed, whereas with the PVC/nitrile foam, flashover occurred quickly and large volumes of high density smoke were emitted. The P-N foam was produced in a pilot plant under carefully controlled conditions. The PVC/nitrile foam was a commercial product. A major phase of the overall program involved fire tests on P-N open-cell foam cushioning.

A systematic multi-step screening of numerous salt hydrates for low temperature thermochemical energy storage

International Nuclear Information System (INIS)

N’Tsoukpoe, Kokouvi Edem; Schmidt, Thomas; Rammelberg, Holger Urs; Watts, Beatriz Amanda; Ruck, Wolfgang K.L.

2014-01-01

Highlights: • We report an evaluation of the potential of salt hydrates for thermochemical storage. • Both theoretical calculations and experimental measurements using TGA/DSC are used. • Salt hydrates offer very low potential for thermochemical heat storage. • The efficiency of classical processes using salt hydrates is very low: typically 25%. • New processes are needed for the use of salt hydrates in thermochemical heat storage. - Abstract: In this paper, the potential energy storage density and the storage efficiency of salt hydrates as thermochemical storage materials for the storage of heat generated by a micro-combined heat and power (micro-CHP) have been assessed. Because salt hydrates used in various thermochemical heat storage processes fail to meet the expectations, a systematic evaluation of the suitability of 125 salt hydrates has been performed in a three-step approach. In the first step general issues such as toxicity and risk of explosion have been considered. In the second and third steps, the authors implement a combined approach consisting of theoretical calculations and experimental measurements using Thermogravimetric Analysis (TGA). Thus, application-oriented comparison criteria, among which the net energy storage density of the material and the thermal efficiency, have been used to evaluate the potential of 45 preselected salt hydrates for a low temperature thermochemical heat storage application. For an application that requires a discharging temperature above 60 °C, SrBr 2 ·6H 2 O and LaCl 3 ·7H 2 O appear to be the most promising, only from thermodynamic point of view. However, the maximum net energy storage density including the water in the water storage tank that they offer (respectively 133 kW h m −3 and 89 kW h m −3 ) for a classical thermochemical heat storage process are not attractive for the intended application. Furthermore, the thermal efficiency that would result from the storage process based on salt hydrates

Microstructure and Deformation Response of TRIP-Steel Syntactic Foams to Quasi-Static and Dynamic Compressive Loads

Science.gov (United States)

Ehinger, David; Weise, Jörg; Baumeister, Joachim; Funk, Alexander; Krüger, Lutz; Martin, Ulrich

2018-01-01

The implementation of hollow S60HS glass microspheres and Fillite 106 cenospheres in a martensitically transformable AISI 304L stainless steel matrix was realized by means of metal injection molding of feedstock with varying fractions of the filler material. The so-called TRIP-steel syntactic foams were studied with respect to their behavior under quasi-static compression and dynamic impact loading. The interplay between matrix material behavior and foam structure was discussed in relation to the findings of micro-structural investigations, electron back scatter diffraction EBSD phase analyses and magnetic measurements. During processing, the cenospheres remained relatively stable retaining their shape while the glass microspheres underwent disintegration associated with the formation of pre-cracked irregular inclusions. Consequently, the AISI 304L/Fillite 106 syntactic foams exhibited a higher compression stress level and energy absorption capability as compared to the S60HS-containing variants. The α′ -martensite kinetic of the steel matrix was significantly influenced by material composition, strain rate and arising deformation temperature. The highest ferromagnetic α′-martensite phase fraction was detected for the AISI 304L/S60HS batches and the lowest for the TRIP-steel bulk material. Quasi-adiabatic sample heating, a gradual decrease in strain rate and an enhanced degree of damage controlled the mechanical deformation response of the studied syntactic foams under dynamic impact loading. PMID:29695107

The axial crushes behaviour on foam-filled round Jute/Polyester composite tubes

Science.gov (United States)

Othman, A.; Ismail, A. E.

2018-04-01

The present paper investigates the effect of axial loading compression on jute fibre reinforced polyester composite round tubes. The specimen of composite tube was fabricated by hand lay-up method of 120 mm length with fix 50.8 mm inner diameter to determine the behaviour of energy absorption on number of layers of 450 angle fibre and internally reinforced with and without foam filler material. The foam filler material used in this studies were polyurethane (PU) and polystyrene (PE) with average of 40 and 45 kg/m3 densities on the axial crushing load against displacement relations and on the failure modes. The number of layers of on this study were two; three and four were selected to calculate the crush force efficiency (CFE) and the specific energy absorption (SEA) of the composite tubes. Result indicated that the four layers’ jute/polyester show significant value in term of crushing load compared to 2 and 3 layers higher 60% for 2 layer and 3% compared to 3 layers. It has been found that the specific energy absorption of the jute/polyester tubes with polystyrene foam-filled is found higher respectively 10% to 12% than empty and polyurethane (PU) foam tubes. The increase in the number of layers from two to four increases the mean axial load from 1.01 KN to 3.60 KN for empty jute/polyester and from 2.11 KN to 4.26 KN for the polyurethane (PU) foam-filled jute/polyester tubes as well as for 3.60 KN to 5.58 KN for the polystyrene (PE) foam-filled jute/polyester. The author’s found that the failure of mechanism influence the characteristic of curve load against displacement obtained and conclude that an increasing number of layers and introduce filler material enhance the capability of specific absorbed energy.

Developing an objective function to characterize the tradeoffs in salting out and the foam and droplet fractionation processes

Directory of Open Access Journals (Sweden)

Cherry J.

2000-01-01

Full Text Available There are many methods for separating and purifying proteins from dilute solutions, such as salting out/precipitation, adsorption/chromatography, foam fractionation, and droplet fractionation. In order to determine the optimal condition for a selected separation and purification process, an objective function is developed. The objective function consists of three parameters, which are the protein mass recovery, the separation ratio, and the enzymatic activity ratio. In this paper the objective function is determined as a function of the pH of the bulk solution for egg albumin, cellulase, and sporamin (for foam fractionation and invertase ( for droplet fractionation. It is found that the optimal pH for all the systems except for cellulase is near their isoelectric point.

Elasto-Plastic Behavior of Aluminum Foams Subjected to Compression Loading

Science.gov (United States)

Silva, H. M.; Carvalho, C. D.; Peixinho, N. R.

2017-05-01

The non-linear behavior of uniform-size cellular foams made of aluminum is investigated when subjected to compressive loads while comparing numerical results obtained in the Finite Element Method software (FEM) ANSYS workbench and ANSYS Mechanical APDL (ANSYS Parametric Design Language). The numerical model is built on AUTODESK INVENTOR, being imported into ANSYS and solved by the Newton-Raphson iterative method. The most similar conditions were used in ANSYS mechanical and ANSYS workbench, as possible. The obtained numerical results and the differences between the two programs are presented and discussed

Infiltrated carbon foam composites

Science.gov (United States)

Lucas, Rick D. (Inventor); Danford, Harry E. (Inventor); Plucinski, Janusz W. (Inventor); Merriman, Douglas J. (Inventor); Blacker, Jesse M. (Inventor)

2012-01-01

An infiltrated carbon foam composite and method for making the composite is described. The infiltrated carbon foam composite may include a carbonized carbon aerogel in cells of a carbon foam body and a resin is infiltrated into the carbon foam body filling the cells of the carbon foam body and spaces around the carbonized carbon aerogel. The infiltrated carbon foam composites may be useful for mid-density ablative thermal protection systems.

Wire-Array Precursor Plasma Interactions With On-Axis Foam Targets

Science.gov (United States)

Palmer, J. B. A.; Bland, S. N.

2005-10-01

The Dynamic Hohlraum (DH) Z-pinch on Z at Sandia National Laboratory (SNL) has been used to drive Inertial Confinement Fusion (ICF) and High Energy Density Physics (HEDP) relevant experiments. The power pulse from the DH cannot yet be reproduced using codes that can reproduce the performance of a Vacuum Hohlraum (VH) configuration on Z. Unlike the VH the DH has a low-density CH foam cylinder placed on the array axis. Production of precursor plasma, prior to the main implosion, is not included in the codes. This plasma is accelerated towards the array axis by the global J x B force and impacts onto the on-axis target. This bombardment alters the foam in various ways. Experiments have been performed on the 1 MA MAGPIE generator at Imperial College, London, to investigate the effect of this precursor bombardment. Diagnostics used were point-projection radiography with x-pinches, x-ray emission framing cameras, shadowgraphy and photoconduction diodes. Results show ablation of low-density plasma from the foam surface and compression of the foam by precursor pressure. Research sponsored by AWE, SNL, the SSAA program of NNSA under DOE Cooperative Agreement DE-FC03-02NA00057.

Hydroxyapatite fiber reinforced poly(alpha-hydroxy ester) foams for bone regeneration

Science.gov (United States)

Thomson, R. C.; Yaszemski, M. J.; Powers, J. M.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

1998-01-01

A process has been developed to manufacture biodegradable composite foams of poly(DL-lactic-co-glycolic acid) (PLGA) and hydroxyapatite short fibers for use in bone regeneration. The processing technique allows the manufacture of three-dimensional foam scaffolds and involves the formation of a composite material consisting of a porogen material (either gelatin microspheres or salt particles) and hydroxyapatite short fibers embedded in a PLGA matrix. After the porogen is leached out, an open-cell composite foam remains which has a pore size and morphology defined by the porogen. By changing the weight fraction of the leachable component it was possible to produce composite foams with controlled porosities ranging from 0.47 +/- 0.02 to 0.85 +/- 0.01 (n = 3). Up to a polymer:fiber ratio of 7:6, short hydroxyapatite fibers served to reinforce low-porosity PLGA foams manufactured using gelatin microspheres as a porogen. Foams with a compressive yield strength up to 2.82 +/- 0.63 MPa (n = 3) and a porosity of 0.47 +/- 0.02 (n = 3) were manufactured using a polymer:fiber weight ratio of 7:6. In contrast, high-porosity composite foams (up to 0.81 +/- 0.02, n = 3) suitable for cell seeding were not reinforced by the introduction of increasing quantities of hydroxyapatite short fibers. We were therefore able to manufacture high-porosity foams which may be seeded with cells but which have minimal compressive yield strength, or low porosity foams with enhanced osteoconductivity and compressive yield strength.

Innovative User Defined Density Profile Approach To FSW Of Aluminium Foam

International Nuclear Information System (INIS)

Contorno, Dorotea; Fratini, Livan; Filice, Luigino; Gagliardi, Francesco; Umbrello, Domenico; Shivpuri, Rajiv

2007-01-01

Metallic foams are one of the most exciting materials in the world of mechanical industry due to their reduced mass and the good mechanical, thermal and acoustic characteristics. Consequently, their application, is increasing day by day even with the important drawbacks that reduce their suitability and diffusion such as high manufacturing cost and difficulty in processing. An innovative approach is outlined in this paper that enables the production of complex shapes taking advantage of deformation processing and friction stir welding (FSW). The aim is to create customized tailored manufactured parts. The cellular construction of foams makes this approach rather challenging as the cell walls are extremely thin and deform unpredictably especially in the presence of rotating and moving hard tool. In this paper, an integrated approach to overcome some of the above challenges is proposed. The initial density is modified by using simple deformation processes, in order to obtained the desired 'crushed density', customized for the intended application. Then, the panels are joined to specially designed solid blocks by using FSW process with a proper set-up. Finally, the obtained specimens are evaluated for mechanical performance and the quality of the joint.

Properties of single-walled carbon nanotube-based aerogels as a function of nanotube loading

International Nuclear Information System (INIS)

Worsley, Marcus A.; Pauzauskie, Peter J.; Kucheyev, Sergei O.; Zaug, Joseph M.; Hamza, Alex V.; Satcher, Joe H.; Baumann, Theodore F.

2009-01-01

Here, we present the synthesis and characterization of low-density single-walled carbon nanotube-based aerogels (SWNT-CA). Aerogels with varying nanotube loading (0-55 wt.%) and density (20-350 mg cm -3 ) were fabricated and characterized by four-probe method, electron microscopy, Raman spectroscopy and nitrogen porosimetry. Several properties of the SWNT-CAs were highly dependent upon nanotube loading. At nanotube loadings of 55 wt.%, shrinkage of the aerogel monoliths during carbonization and drying was almost completely eliminated. Electrical conductivities are improved by an order of magnitude for the SWNT-CA (55 wt.% nanotubes) compared to those of foams without nanotubes. Surface areas as high as 184 m 2 g -1 were achieved for SWNT-CAs with greater than 20 wt.% nanotube loading.

A study on conductivity, density, and viscosity of molten salt systems

International Nuclear Information System (INIS)

Cho, Kangjo

1976-01-01

A relation between the equivalent conductivity and density for molten salts is deduced with the aid of significant structures theory, and the solid state density at melting point is evaluated approximately for some rare-earth metal chlorides and the other chlorides. Furthermore, the relation among the equivalent conductivity, density, and viscosity for some molten salts is discussed. (auth.)

Extraction behavior of uranium(VI) with polyurethane foam

International Nuclear Information System (INIS)

Tingchia Huang; Donghwang Chen; Muchang Shieh; Chingtsven Huang

1992-01-01

The extraction of uranium(VI) from aqueous solution with polyether-based polyurethane (PU) foam was studied. The effects of the kinds and concentrations of nitrate salts, uranium(VI) concentration, temperature, nitric acid concentration, pH, the content of poly(ethylene oxide) in the polyurethane foam, and the ratio of PU foam weight and solution volume on the extraction of uranium(VI) were investigated. The interferences of fluoride and carbonate ions on the extraction of uranium(VI) were also examined, and methods to overcome both interferences were suggested. It was found that no uranium was extracted in the absence of a nitrate salting-out agent, and the extraction behaviors of uranium(IV) with polyurethane foam could be explained in terms of an etherlike solvent extraction mechanism. In addition, the percentage extraction of a multiple stage was also estimated theoretically

Identification of strain fields in pure Al and hybrid Ni/Al metal foams using X-ray micro-tomography under loading

International Nuclear Information System (INIS)

Fíla, T.; Jiroušek, O.; Jung, A.; Kumpová, I.

2016-01-01

Hybrid foams are materials formed by a core from a standard open cell metal foam that is during the process of electrodeposition coated by a thin layer of different nanocrystalline metals. The material properties of the base metal foam are in this way modified resulting in higher plateau stress and, more importantly, by introduction of strain-rate dependence to its deformation response. In this paper, we used time-lapse X-ray micro-tomography for the mechanical characterization of Ni/Al hybrid foams (aluminium open cell foams with nickel coating layer). To fully understand the effects of the coating layer on the material's effective properties, we compared the compressive response of the base uncoated foam to the response of the material with coating thickness of 50 and 75 μm. Digital volume correlation (DVC) was applied to obtain volumetric strain fields of the deforming micro-structure up to the densification region of the deforming cellular structure. The analysis was performed as a compressive mechanical test with simultaneous observation using X-ray radiography and tomography. A custom design experimental device was used for compression of the foam specimens in several deformation states directly in the X-ray setup. Planar X-ray images were taken during the loading phases and a X-ray tomography was performed at the end of each loading phase (up to engineering strain 22%). The samples were irradiated using micro-focus reflection type X-ray tube and images were taken using a large area flat panel detector. Tomography reconstructions were used for an identification of a strain distribution in the foam using digital volumetric correlation. A comparison of the deformation response of the coated and the uncoated foam in uniaxial quasi-static compression is summarized in the paper.

Surface properties of AZ91 magnesium alloy after PEO treatment using molybdate salts and low current densities

Energy Technology Data Exchange (ETDEWEB)

Pezzato, Luca, E-mail: luca.pezzato@studenti.unipd.it [Department of Industrial Engineering, University of Padua, Via Marzolo 9, 35131 Padova (Italy); Brunelli, Katya [Department of Industrial Engineering, University of Padua, Via Marzolo 9, 35131 Padova (Italy); Napolitani, Enrico [MATIS-IMM-CNR and Dipartimento di Astronomia e Fisica, University of Padua, Via Marzolo 8, 35131 Padova (Italy); Magrini, Maurizio; Dabalà, Manuele [Department of Industrial Engineering, University of Padua, Via Marzolo 9, 35131 Padova (Italy)

2015-12-01

Graphical abstract: - Highlights: • Low concentrations of molybdate stopped PEO process at the first step. • High concentrations of molybdate produce the start of the second and third stages. • The layer after the first step is thin but dense and homogeneous. • The sample treated with low amount of molybdate is the one with best corrosion resistance. - Abstract: Plasma electrolytic oxidation (PEO) process is a recently developed electrochemical method used to produce on the surface of various metals oxide ceramic coatings that improve corrosion and wear properties of the substrate. In this work, PEO process was applied on AZ91 magnesium alloy using low current densities (0.05 A/cm{sup 2}) and an alkaline solution of silicates with different concentrations of sodium molybdate (0.3–3 g/l). The effect of the low current densities of process and of molybdate salts on the corrosion resistance of the coatings was studied with potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) in chloride and sulfate environment. The morphology, the phases and the chemical composition of the coatings were examined using a scanning electron microscope equipped with EDS, X-ray diffraction, secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The corrosion properties of the PEO coated samples were remarkably improved if compared with the uncoated samples. The addition of sodium molybdate, in determinate conditions, had a positive effect on the characteristics of the coatings in terms of corrosion resistance.

The Response of Clamped Shallow Sandwich Arches with Metallic Foam Cores to Projectile Impact Loading

Directory of Open Access Journals (Sweden)

Yanping Fan

Full Text Available Abstract The dynamic response and energy absorption capabilities of clamped shallow sandwich arches with aluminum foam core were numerically investigated by impacting the arches at mid-span with metallic foam projectiles. The typical deformation modes, deflection response, and core compression of sandwich arches obtained from the tests were used to validate the computation model. The resistance to impact loading was quantified by the permanent transverse deflection at mid-span of the arches as a function of projectile momentum. The sandwich arches have a higher shock resistance than the monolithic arches of equal mass, and shock resistance could be significantly enhanced by optimizing geometrical configurations. Meanwhile, decreasing the face-sheet thickness and curvature radius could enhance the energy absorption capability of the sandwich arches. Finite element calculations indicated that the ratio of loading time to structural response time ranged from 0.1 to 0.4. The projectile momentum, which was solely used to quantify the structural response of sandwich arches, was insufficient. These findings could provide guidance in conducting further theoretical studies and producing the optimal design of metallic sandwich structures subjected to impact loading.

Preliminary design of a low-cost greenhouse for salt production in Indonesia

Science.gov (United States)

Jaziri, A. A.; Guntur; Setiawan, W.; Prihanto, A. A.; Kurniawan, A.

2018-04-01

Salt is an assential material of industry, not only in food industry point of view but also in various industries such as chemical, oil drilling, and animal feed industries, even less than half of salt needs used to household consumption. It is crucial to ensure salt production in Indonesia reaches the national target (3.7 million tons) due to relatively low technology and production level. Thus salt production technology is developed to facilitate farmers consisted of geomembrane and filtering-threaded technology. However, the use of those technologies in producing salt was proved less effective due to unpredictable weather conditions. Therefore, greenhouse technology is proposed to be used for salt production for several good reasons. This paper describes the preliminary design of a low-cost greenhouse designed as a pyramid model that uses bamboo, mono-layer and high density polyethylene plastics. The results confirmed that the yield of salt produced by greenhouse significantly incresed compared with prior technology and the NaCl content increased as well. The cost of greenhouse was IDR 5,688,000 and easy to assembly.

Development of rubidium and niobium containing plastic foams. Final report

International Nuclear Information System (INIS)

Botham, R.A.; McClung, C.E.; Schwendeman, J.I.

1978-01-01

Rubidium fluoride and niobium metal-containing foam samples (rods and sheets) were prepared using two foam sytems: (1) hydrophilic polyurethanes prepared from W.R. Grace Co.'s Hypol prepolymers and (2) polyimides prepared from Monsanto Company's Skybond polyimide resin. The first system was used only for preparation of rubidium fluoride-containing foams while the second was used for both rubidium fluoride and niobium-containing foams. The niobium metal could readily be incorporated into the polyimide foam during molding, to produce foam sheets of the required dimensions and density. The rubidium fluoride-containing polyimide foams were preferably prepared by first rendering the molded polyimide foam hydrophilic with a postcuring treatment, then absorbing the rubidium fluoride from water solution. Similarly, rubidium fluoride was absorbed into the hydrophilic polyurethanes from water solution. Since the high reactive rubidium metal could not be employed, rubidium fluoride, which is very hygroscopic, was used instead, primarily because of its high rubidium content (approximately 82 weight percent). This was important in view of the low total densities and the high weight percentage rubidium required in the foam samples. In addition, at the later request of LLL, a block of rigid Hypol hydrophilic polyurethane foam (with a density of approximately 0.04 g/cm 3 and cell sizes = or <0.2 mm) was prepared without any metal or metal compounds in it. Two shipments of foam samples, which met or closely approximated the project specifications, were submitted to LLL during the course of this project. Information on these samples is contained in Table 1. A complete description of their preparation is given in the Experimental Results and Discussion Section

Density, viscosity, and N2O solubility of aqueous amino acid salt and amine amino acid salt solutions

International Nuclear Information System (INIS)

Aronu, Ugochukwu E.; Hartono, Ardi; Svendsen, Hallvard F.

2012-01-01

Highlights: ► Density of amino acid salt and amine amino acid salt. ► Viscosity of amino acid salt and amine amino acid salt. ► Henry’s law constant/N 2 O solubility of amino acid salt and amine amino acid salt. ► Schumpe model. Correlations for density, viscosity, and N 2 O solubility. - Abstract: Physicochemical properties of aqueous amino acid salt (AAS), potassium salt of sarcosine (KSAR) and aqueous amine amino acid salt (AAAS), 3-(methylamino)propylamine/sarcosine (SARMAPA) have been studied. Densities of KSAR were measured for sarcosine mole fraction 0.02 to 0.25 for temperature range 298.15 K to 353.15 K, the viscosities were measured for 0.02 to 0.10 mole fraction sarcosine (293.15 K to 343.15 K) while the N 2 O solubilities were measured from 0.02 to 0.10 mole fraction sarcosine solutions (298.15 K to 363.15 K). Densities of SARMAPA were measured for sarcosine mole fraction 0.02 to 0.23 for temperature range (298.15 K to 353.15 K), viscosities were measured for 0.02 to 0.16 mole fraction sarcosine (293.15 K to 343.15 K) while the N 2 O solubilities were measured from 0.02 to 0.16 mole fraction sarcosine solutions (298.15 K to 343.15 K). Experimental results were correlated well with empirical correlations and N 2 O solubility results for KSAR were predicted adequately by a Schumpe model. The solubilities of N 2 O in AAS and AAAS are significantly lower than values for amines. The solubilities vary as: amine > AAAS > AAS.

All-dielectric invisibility cloaks made of BaTiO3-loaded polyurethane foam

International Nuclear Information System (INIS)

Bao Di; Rajab, Khalid Z; Hao Yang; Kallos, Efthymios; Tang, Wenxuan; Argyropoulos, Christos; Piao Yongzhe; Yang Shoufeng

2011-01-01

Transformation optics has led the way in the development of electromagnetic invisibility cloaks from science fiction to engineering practice. Invisibility cloaks have been demonstrated over a wide range of the electromagnetic spectrum, and with a variety of different fabrication techniques. However, all previous schemes have relied on the use of metamaterials consisting of arrays of sub-wavelength inclusions. We report on the first cloaking structure made of a high-κ dielectric-loaded foam mixture. A polyurethane foam mixed with different ratios of barium titanate is used to produce the required range of permittivities, and the invisibility cloak is demonstrated to work for all incident angles over a wide range of microwave frequencies. This method will greatly facilitate the development and large-scale manufacture of a wide range of transformation optics-based structures. (paper)

Emissivity Measurements of Foam-Covered Water Surface at L-Band for Low Water Temperatures

Directory of Open Access Journals (Sweden)

En-Bo Wei

2014-11-01

Full Text Available For a foam-covered sea surface, it is difficult to retrieve sea surface salinity (SSS with L-band brightness temperature (1.4 GHz because of the effect of a foam layer with wind speeds stronger than 7 m/s, especially at low sea surface temperature (SST. With foam-controlled experiments, emissivities of a foam-covered water surface at low SST (−1.4 °C to 1.7 °C are measured for varying SSS, foam thickness, incidence angle, and polarization. Furthermore, a theoretical model of emissivity is introduced by combining wave approach theory with the effective medium approximation method. Good agreement is obtained upon comparing theoretical emissivities with those of experiments. The results indicate that foam parameters have a strong influence on increasing emissivity of a foam-covered water surface. Increments of experimental emissivities caused by foam thickness of 1 cm increase from about 0.014 to 0.131 for horizontal polarization and 0.022 to 0.150 for vertical polarization with SSS increase and SST decrease. Contributions of the interface between the foam layer and water surface to the foam layer emissivity increments are discussed for frequencies between 1 and 37 GHz.

Different catalysts for new polyols for rigid PUR-PIR foams

Directory of Open Access Journals (Sweden)

Liszkowska Joanna

2015-12-01

Full Text Available New polyols were synthesized with 2-hydroxypropane-1.2.3-tricarboxylic acid and butane-1,4-diol (1.4-BD. The synthesis was performed using different catalysts in the amount of 0.1%. Used catalyst: Tyzor TPT, tin(II acetate, sulfuric(IV acid. The fourth reaction was conducted without the use of a catalyst. The polyols’ properties were evaluated with regards to the usefulness in rigid polyurethane-polyisocyanurate (PUR-PIR foams (acid value, density, pH and solubility, FTIR spectra. Based on the research, it was evaluated that only the polyol synthesized using Tyzor TPT (E6 was useful in production of rigid PUR-PIR foams. Its hydroxyl number was 496 mgKOH/g and its viscosity was about 14 552 mPa · s. A series of five foams P6.1–P6.5 was produced with this polyol. Rigid foams test results indicated that the amount of this compound in the foam substantially affects its compressive strength, density and their retention. The foams have low brittleness values.

Adsorption of Sr(II) on clay minerals: effects of salt concentration, loading and pH

International Nuclear Information System (INIS)

Rafferty, P.; Shiao, S.Y.; Binz, C.M.; Meyer, R.E.

1981-01-01

The adsorption of Sr(II) on a number of clay minerals has been investigated by means of a batch technique in solutions of sodium salts. Generally the results can be approximated by ideal ion exchange equations. Distribution coefficients at trace loading follow the linear relation log D = s log [Na(I)sub(aq)] + b where b is a constant and s had values of from about - 1.5 to - 2.0, which are fairly close to the ideal valve of - 2. Adsorption isotherms at constant pH and salt concentration are linear in the low loading region. Distribution coefficients for montmorillonite are almost independent of pH in the intermediate pH region 5 to 7 but for illite and kaolinite, increases in the distribution coefficient with pH are observed. Comparison of these results with literature values, insofar as it is possible, shows that distribution coefficients are usually within a factor of two or three for the same mineral with similar capacities under the same conditions even if techniques of preparation and measurement are different, but values may vary considerably more if the capacities of the different mineral samples are greatly different. Values of the distribution coefficient at very high salt concentration are very low, considerably less than unity at 4 M NaCl. Thus migration rates of Sr(II), relative to water flow, through geologic formations whose adsorption behavior is dominated by these clay minerals are likely to be high at high salt concentrations. (author)

The mechanical behavior of microcellular foams

Energy Technology Data Exchange (ETDEWEB)

Ozkul, M.H.; Mark, J.E. (Cincinnati Univ., OH (USA)); Aubert, J.H. (Sandia National Labs., Albuquerque, NM (USA))

1990-01-01

The mechanical behavior of microcellular open-cell foams prepared by a thermally induced phase separation process are investigated. The foams studied were prepared from isotactic polystyrene, polyacrylonitrile, and poly(4-methyl-1-pentene) (rigid foams), and polyurethane and Lycra (elastomeric foams). Their densities were in the range 0.04--0.27 g/cm3. Conventional polystyrene foams were used for comparison. The moduli and collapse stresses of these foams were measured in compression and compared with the current constitutive laws which relate mechanical properties to densities. A reinforcement technique based on the in-situ precipitation of silica was used to improve the mechanical properties. 13 refs., 4 figs., 3 tabs.

Microstructure of high-strength foam concrete

International Nuclear Information System (INIS)

Just, A.; Middendorf, B.

2009-01-01

Foam concretes are divided into two groups: on the one hand the physically foamed concrete is mixed in fast rotating pug mill mixers by using foaming agents. This concrete cures under atmospheric conditions. On the other hand the autoclaved aerated concrete is chemically foamed by adding aluminium powder. Afterwards it is cured in a saturated steam atmosphere. New alternatives for the application of foam concretes arise from the combination of chemical foaming and air curing in manufacturing processes. These foam concretes are new and innovative building materials with interesting properties: low mass density and high strength. Responsible for these properties are the macro-, meso- and microporosity. Macropores are created by adding aluminium powder in different volumes and with different particle size distributions. However, the microstructure of the cement matrix is affected by meso- and micropores. In addition, the matrix of the hardened cement paste can be optimized by the specific use of chemical additives for concrete. The influence of aluminium powder and chemical additives on the properties of the microstructure of the hardened cement matrices were investigated by using petrographic microscopy as well as scanning electron microscopy.

Treatment of low level radioactive liquid wastes using composite ion-exchange resins based on polyurethane foam

International Nuclear Information System (INIS)

Rao, S.V.S.; Lekshmi, R.; Mani, A.G.S.; Sinha, P.K.

2010-01-01

Composite ion-exchange resins were prepared by coating copper-ferrocyanide (CFC) and hydrous manganese oxide (HMO) powders on polyurethane (PU) foam. Polyvinyl acetate/Acetone was used as a binder. The foam was loaded with about five times its weight with CFC and HMO powders. The distribution coefficients of CFC-PU foam and HMO-PU foam for cesium and strontium respectively were estimated. Under similar conditions the HMO-PU foam showed higher capacity as well as better kinetics for removal of strontium than CFC-PU foam for Cs. The pilot plant scale studies were conducted using a mixed composite ion-exchange resin bed. About 1000 bed volumes could be passed before attaining a DF of 10 from an initial value of 60-80. The spent resin was digested in alkaline KMnO 4 and the digested liquid was fixed in cement matrix. The matrices were characterized with respect to compressive strength and leach resistance. (author)

Large-Scale Liquid Hydrogen Testing of Variable Density Multilayer Insulation with a Foam Substrate

Science.gov (United States)

Martin, J. J.; Hastings, L.

2001-01-01

The multipurpose hydrogen test bed (MHTB), with an 18-cu m liquid hydrogen tank, was used to evaluate a combination foam/multilayer combination insulation (MLI) concept. The foam element (Isofoam SS-1171) insulates during ground hold/ascent flight, and allowed a dry nitrogen purge as opposed to the more complex/heavy helium purge subsystem normally required. The 45-layer MLI was designed for an on-orbit storage period of 45 days. Unique WI features include a variable layer density, larger but fewer double-aluminized Mylar perforations for ascent to orbit venting, and a commercially established roll-wrap installation process that reduced assembly man-hours and resulted in a roust, virtually seamless MLI. Insulation performance was measured during three test series. The spray-on foam insulation (SOFI) successfully prevented purge gas liquefaction within the MLI and resulted in the expected ground hold heat leak of 63 W/sq m. The orbit hold tests resulted in heat leaks of 0.085 and 0.22 W/sq m with warm boundary temperatures of 164 and 305 K, respectively. Compared to the best previously measured performance with a traditional MLI system, a 41-percent heat leak reduction with 25 fewer MLI layers was achieved. The MHTB MLI heat leak is half that calculated for a constant layer density MLI.

Elaboration of recycled polyethylene foams reticulated by radiation

International Nuclear Information System (INIS)

Galicia M, M.

2000-01-01

In this work some obtained results are presented to make irradiation tests on recycled polymeric material (polyethylene) as well as mixtures of this with certain additive classes (foaming and reticulating agents) which will be used for the foams elaboration, objective of this work. Two types of foaming basically exist which are elaborated with low density polyethylene base. They are: a) the extruded and, b) the reticulated through ionizing radiation and chemically. Some of the properties that the expanded or foamed polyethylene are: flexibility, resistance, thermal stability, inter medium mechanical properties between the highly flexible foams and rigid among others. All of them determined by the cell type which conform them. Also was carried out the characterization of the obtained material contributing of this manner to diminish the quantity of solid wastes generated. (Author)

Fluid-Phase Pinocytosis of Native Low Density Lipoprotein Promotes Murine M-CSF Differentiated Macrophage Foam Cell Formation

Science.gov (United States)

Xu, Qing; Bohnacker, Thomas; Wymann, Matthias P.; Kruth, Howard S.

2013-01-01

During atherosclerosis, low-density lipoprotein (LDL)-derived cholesterol accumulates in macrophages to form foam cells. Macrophage uptake of LDL promotes foam cell formation but the mechanism mediating this process is not clear. The present study investigates the mechanism of LDL uptake for macrophage colony-stimulating factor (M-CSF)-differentiated murine bone marrow-derived macrophages. LDL receptor-null (LDLR−/−) macrophages incubated with LDL showed non-saturable accumulation of cholesterol that did not down-regulate for the 24 h examined. Incubation of LDLR−/− macrophages with increasing concentrations of 125I-LDL showed non-saturable macrophage LDL uptake. A 20-fold excess of unlabeled LDL had no effect on 125I-LDL uptake by wild-type macrophages and genetic deletion of the macrophage scavenger receptors CD36 and SRA did not affect 125I-LDL uptake, showing that LDL uptake occurred by fluid-phase pinocytosis independently of receptors. Cholesterol accumulation was inhibited approximately 50% in wild-type and LDLR−/− mice treated with LY294002 or wortmannin, inhibitors of all classes of phosphoinositide 3-kinases (PI3K). Time-lapse, phase-contrast microscopy showed that macropinocytosis, an important fluid-phase uptake pathway in macrophages, was blocked almost completely by PI3K inhibition with wortmannin. Pharmacological inhibition of the class I PI3K isoforms alpha, beta, gamma or delta did not affect macrophage LDL-derived cholesterol accumulation or macropinocytosis. Furthermore, macrophages from mice expressing kinase-dead class I PI3K beta, gamma or delta isoforms showed no decrease in cholesterol accumulation or macropinocytosis when compared with wild-type macrophages. Thus, non-class I PI3K isoforms mediated macropinocytosis in these macrophages. Further characterization of the components necessary for LDL uptake, cholesterol accumulation, and macropinocytosis identified dynamin, microtubules, actin, and vacuolar type H(+)-ATPase as

Evaluation of mechanical properties and low velocity impact characteristics of balsa wood and urethane foam applied to impact limiter of nuclear spent fuel shipping cask

Energy Technology Data Exchange (ETDEWEB)

Goo, Junsung; Shin, Kwangbok [Hanbat Nat' l Univ., Daejeon (Korea, Republic of); Choi, Woosuk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-11-15

The paper aims to evaluate the low velocity impact responses and mechanical properties of balsa wood and urethane foam core materials and their sandwich panels, which are applied as the impact limiter of a nuclear spent fuel shipping cask. For the urethane foam core, which is isotropic, tensile, compressive, and shear mechanical tests were conducted. For the balsa wood core, which is orthotropic and shows different material properties in different orthogonal directions, nine mechanical properties were determined. The impact test specimens for the core material and their sandwich panel were subjected to low velocity impact loads using an instrumented testing machine at impact energy levels of 1, 3, and 5J. The experimental results showed that both the urethane foam and the balsa wood core except in the growth direction (z-direction) had a similar impact response for the energy absorbing capacity, contact force, and indentation. Furthermore, it was found that the urethane foam core was suitable as an impact limiter material owing to its resistance to fire and low cost, and the balsa wood core could also be strongly considered as an impact limiter material for a lightweight nuclear spent fuel shipping cask.

Bi-liquid foams

International Nuclear Information System (INIS)

Sonneville, Odile

1997-01-01

Concentrated emulsions have structures similar to foams; for this reason they are also called 'bi-liquid foams'. For oil in water emulsions, they are made of polyhedral oil cells separated by aqueous surfactant films. The limited stability of these Systems is a major nuisance in their applications. In this work, we tried to understand and to control the mechanisms through which bi-liquid foams can loose their stability. In a first stage, we characterized the states of surfactant films in bi-liquid foams submitted to different pressures. We determined their hydration, the surfactant density at interfaces as well as their thicknesses. The bi-liquid foams were made by concentrating hexadecane-in-water emulsions through centrifugation. The initial emulsions contained submicron oil droplets that were completely covered with surfactant. We measured the resistance of the films to dehydration, and we represented it by pressure-film thickness curves or pressure-film hydration curves. We also obtained evidence that the interfacial surfactant density increases when the film thickness is decreased (SDS case). The Newton Black Film state is the most dehydrated metastable state that can be reached. In this state, the films can be described as surfactant bilayers that only contain the hydration water of the surfactant polar heads. Two different processes are involved the destabilization of bi-liquid foams: Ostwald ripening (oil transfer from small cells to large cells) and coalescence (films rupture). The first mechanism can be controlled by choosing oils that are very insoluble in water, avoiding ethoxylated nonionic surfactants of low molecular weight, and making emulsions that are not too fine. The second mechanism is responsible for the catastrophic destabilization of bi-liquid foams made of droplets above one micron or with a low coverage in surfactant. In these cases, destabilization occurs in the early stages of concentration, when the films are still thick. It is caused

Analysis of Stainless Steel Sandwich Panels with a Metal Foam Care for Lightweight Fan Blade Design

Science.gov (United States)

Min, James B.; Ghosn, Louis J.; Lerch, Bradley A.; Raj, Sai V.; Holland, Frederic A., Jr.; Hebsur, Mohan G.

2004-01-01

The quest for cheap, low density and high performance materials in the design of aircraft and rotorcraft engine fan and propeller blades poses immense challenges to the materials and structural design engineers. Traditionally, these components have been fabricated using expensive materials such as light weight titanium alloys, polymeric composite materials and carbon-carbon composites. The present study investigates the use of P sandwich foam fan blade made up of solid face sheets and a metal foam core. The face sheets and the metal foam core material were an aerospace grade precipitation hardened 17-4 PH stainless steel with high strength and high toughness. The stiffness of the sandwich structure is increased by separating the two face sheets by a foam core. The resulting structure possesses a high stiffness while being lighter than a similar solid construction. Since the face sheets carry the applied bending loads, the sandwich architecture is a viable engineering concept. The material properties of 17-4 PH metal foam are reviewed briefly to describe the characteristics of the sandwich structure for a fan blade application. A vibration analysis for natural frequencies and P detailed stress analysis on the 17-4 PH sandwich foam blade design for different combinations of skin thickness and core volume %re presented with a comparison to a solid titanium blade.

MnO2/multiwall carbon nanotube/Ni-foam hybrid electrode for electrochemical capacitor

Science.gov (United States)

Chen, L. H.; Li, L.; Qian, W. J.; Dong, C. K.

2018-01-01

The ternary composites of manganese dioxide/multiwall carbon nanotube/Ni-foam (MnO2/MWNT/Ni-foam) for supercapacitors were fabricated via a hydrothermal method after direct growth of MWNTs on the Ni-foam. The structural properties of the electrodes were characterized by SEM and TEM. The electrode exhibited excellent electrochemical properties from the investigation based on the three-electrode setup. Low contact resistance Rs of about 0.291 Ω between MnO2/MWNT and Ni-foam was reached benefited from the direct growth structure. High capacitance of 355.1 F/g at the current density of 2 A/g was achieved, with good capacitive response at high current density. The MnO2/MWNT/Ni-foam electrode exhibits good stability performance after 2000 cycles at a current of 40 mA.

State-of-the-Art Review on the Characteristics of Surfactants and Foam from Foam Concrete Perspective

Science.gov (United States)

Sahu, Sritam Swapnadarshi; Gandhi, Indu Siva Ranjani; Khwairakpam, Selija

2018-06-01

Foam concrete finds application in many areas, generally as a function of its relatively lightweight and its beneficial properties in terms of reduction in dead load on structure, excellent thermal insulation and contribution to energy conservation. For production of foam concrete with desired properties, stable and good quality foam is the key requirement. It is to be noted that the selection of surfactant and foam production parameters play a vital role in the properties of foam which in turn affects the properties of foam concrete. However, the literature available on the influence of characteristics of foaming agent and foam on the properties of foam concrete are rather limited. Hence, a more systematic research is needed in this direction. The focus of this work is to provide a review on characteristics of surfactant (foaming agent) and foam for use in foam concrete production.

Preparation of microcellular foam in cylindrical metal targets

International Nuclear Information System (INIS)

Apen, P.G.; Armstrong, S.V.; Moore, J.E.; Espinoza, B.F.; Gurule, V.; Gobby, P.L.; Williams, J.M.

1992-01-01

The preparation of microcellular foam in cylindrical gold targets is described. The goal cylinders were fabricated by electroplating gold onto a silicon bronze mandrel and leaching the mandrel with concentrated nitric acid. After several rinsing and cleaning steps, the cylinders were filled with a solution containing trimethylolpropanetriacrylate (TMPTA). Low density, microcellular polymeric foam was prepared by in situ photopolymerization of the TMPTA solution. Foam preparation was extremely sensitive to metal ion contaminants. In particular, copper ions left behind from the leaching process inhibit polymerization and must be removed in order to obtain uniform, non-shrinking foams. A study on the effects of potential contaminants and polymerization inhibitors on TMPTA photopolymerization is presented. In addition, a procedure for the effective leaching and cleaning of gold cylinders is described

Milestone 5 test report. Task 5, subtask 5.2: Tile to foam strength tests

Science.gov (United States)

Greenberg, H. S.

1994-01-01

This report summarizes work that has been performed to date on the strength of a cryotank insulation system using Rohacell foam and TUFI-coated AETB-12 ceramic tiles directly bonded to a simulated graphite-epoxy tank wall. Testing utilized a custom specimen design which consists of a long tensile specimen with eccentric loading to induce curvature similar to the curvature expected due to 'pillowing' of the tank when pressurized. A finite element model was constructed to predict the specific element strains in the test article, and to assist with design of the test specimen to meet the specific goals of curvature and laminate strain. The results indicate that the heat treated 3.25-pcf density Rohacell foam does not provide sufficient strength for the induced stresses due to curvature and stress concentration at the RTV bondline to the TUFI tile. The test was repeated using higher density non-heat treated Rohacell foam (6.9 pcf) without foam failure. The finite element model was shown to predict specimen behavior, and validation of the model was successful. It is pertinent to mention that the analyses described herein accurately predicted the failure of the heat treated foams and based on this analysis method it is expected that the untreated 3.25 pcf Rohacell foam will be successful.

Kinematics and dynamics of salt movement driven by sub-salt normal faulting and supra-salt sediment accumulation - combined analogue experiments and analytical calculations

Science.gov (United States)

Warsitzka, Michael; Kukowski, Nina; Kley, Jonas

2017-04-01

In extensional sedimentary basins, the movement of ductile salt is mainly controlled by the vertical displacement of the salt layer, differential loading due to syn-kinematic deposition, and tectonic shearing at the top and the base of the salt layer. During basement normal faulting, salt either tends to flow downward to the basin centre driven by its own weight or it is squeezed upward due to differential loading. In analogue experiments and analytical models, we address the interplay between normal faulting of the sub-salt basement, compaction and density inversion of the supra-salt cover and the kinematic response of the ductile salt layer. The analogue experiments consist of a ductile substratum (silicone putty) beneath a denser cover layer (sand mixture). Both layers are displaced by normal faults mimicked through a downward moving block within the rigid base of the experimental apparatus and the resulting flow patterns in the ductile layer are monitored and analysed. In the computational models using an analytical approximative solution of the Navier-Stokes equation, the steady-state flow velocity in an idealized natural salt layer is calculated in order to evaluate how flow patterns observed in the analogue experiments can be translated to nature. The analytical calculations provide estimations of the prevailing direction and velocity of salt flow above a sub-salt normal fault. The results of both modelling approaches show that under most geological conditions salt moves downwards to the hanging wall side as long as vertical offset and compaction of the cover layer are small. As soon as an effective average density of the cover is exceeded, the direction of the flow velocity reverses and the viscous material is squeezed towards the elevated footwall side. The analytical models reveal that upward flow occurs even if the average density of the overburden does not exceed the density of salt. By testing various scenarios with different layer thicknesses

Analytical and Numerical Study of Foam-Filled Corrugated Core Sandwich Panels under Low Velocity Impact

Directory of Open Access Journals (Sweden)

Mohammad Nouri Damghani

2016-05-01

Full Text Available Analytical and finite element simulations are used to predict the effect of core density on the energy absorption of composite sandwich panels under low-velocity impact. The composite sandwich panel contains two facesheets and a foam-filled corrugated core. Analytical model is defined as a two degree-of-freedom system based on equivalent mass, spring, and dashpot to predict the local and global deformation response of a simply supported panel. The results signify a good agreement between analytical and numerical predictions.

Failure mechanisms of closed-cell aluminum foam under monotonic and cyclic loading

International Nuclear Information System (INIS)

Amsterdam, E.; De Hosson, J.Th.M.; Onck, P.R.

2006-01-01

This paper concentrates on the differences in failure mechanisms of Alporas closed-cell aluminum foam under either monotonic or cyclic loading. The emphasis lies on aspects of crack nucleation and crack propagation in relation to the microstructure. The cell wall material consists of Al dendrites and an interdendritic network of Al 4 Ca and Al 22 CaTi 2 precipitates. In situ scanning electron microscopy monotonic tensile tests were performed on small samples to study crack nucleation and propagation. Digital image correlation was employed to map the strain in the cell wall on the characteristic microstructural length scale. Monotonic tensile tests and tension-tension fatigue tests were performed on larger samples to observe the overall fracture behavior and crack path in monotonic and cyclic loading. The crack nucleation and propagation path in both loading conditions are revealed and it can be concluded that during monotonic tension cracks nucleate in and propagate partly through the Al 4 Ca interdendritic network, whereas under cyclic loading cracks nucleate and propagate through the Al dendrites

Characterization of compressive and short beam shear strength of bamboo opened cell foam core sandwich composites

Energy Technology Data Exchange (ETDEWEB)

Setyawan, Paryanto Dwi, E-mail: paryanto-ds@yahoo.com; Sugiman,; Saputra, Yudhi [Department of Mechanical Engineering, Faculty of Engineering, University of Mataram, Mataram, West Nusa Tenggara (Indonesia)

2016-03-29

The paper presents the compressive and the short beam shear strength of a sandwich composite with opened cell foam made of bamboo fiber as the core and plywood as the skins. The core thickness was varied from 10 mm to 40 mm keeping the volume fraction of fiber constant. Several test s were carried out including the core density, flatwise compressive and the short beam shear testing in three point bending. The results show that the density of bamboo opened cell foam is comparable with commercial plastic foam, such as polyurethane foam. The compressive strength tends to increase linearly with increasing the core thickness. The short beam shear failure load of the sandwich composite increases with the increase of core thickness, however on the contrary, the short beam shear strength which tends to sharply decrease from the thickness of 10 mm to 30 mm and then becomes flat.

Pengaruh Penambahan Kitosan dalam Pembuatan Biodegradable Foam Berbahan Baku Pati

Directory of Open Access Journals (Sweden)

Nanik Hendrawati

2017-05-01

Full Text Available Biodegradable foam is an alternative packaging to replace the expanded polystyrene foam packaging currently in use.   Starch has been used to produce foam because of  its low cost, low density, low toxicity, and  biodegradability. Chitosan has been added to improve mechanical properties of product . The   effect of  variation on chitosan amount  and  starch types  was investigated in this study.  The amount of  chitosan  was varied as 0; 5; 10; 15; 20; 25; and  30 % w/w and starch types were used in this research were cassava, Corn and sago starch. Biodegradable  foam was produced by using baking process method, all of material (Starch, Chitosan solution,  Magnesium Stearate, Carrageenan, Glyserol, Protein Isolates  dan polyvinil alcohol (PVOH  were mixed with kitchen aid mixer. The mixture was poured  into mold and heated in an oven at 125 oC for 1 hour. Then, foam was tested for its mechanical properties, water absorption  and biodegradability and  morphology (SEM.  The results show that  foam made from sago starch had lower water absortion than those made from cassava and corn starch.   While, foam made from cassava starch  was more biodegradable than the other foam.  Biodegradable foam based sago starch and 30 % w/w of Chitosan adition  gave the  best performence in tensile stress that  is 20 Mpa

Small Column Ion Exchange Analysis for Removal of Cesium from SRS Low Curie Salt Solutions Using Crystalline Silicotitanate (CST) Resin

International Nuclear Information System (INIS)

ALEMAN, SEBASTIAN

2004-01-01

Savannah River Technology Center (SRTC) researchers modeled ion exchange removal of cesium from dissolved salt waste solutions. The results assist in evaluating proposed configurations for an ion exchange process to remove residual cesium from low curie waste streams. A process for polishing (i.e., removing small amounts) of cesium may prove useful should supernate draining fail to meet the Low Curie Salt (LCS) target limit of 0.1 Ci of Cs-137 per gallon of salt solution. Cesium loading isotherms and column breakthrough curves for Low Curie dissolved salt solutions were computed to provide performance predictions for various column designs

A review of low density porous materials used in laser plasma experiments

Science.gov (United States)

Nagai, Keiji; Musgrave, Christopher S. A.; Nazarov, Wigen

2018-03-01

This review describes and categorizes the synthesis and properties of low density porous materials, which are commonly referred to as foams and are utilized for laser plasma experiments. By focusing a high-power laser on a small target composed of these materials, high energy and density states can be produced. In the past decade or so, various new target fabrication techniques have been developed by many laboratories that use high energy lasers and consequently, many publications and reviews followed these developments. However, the emphasis so far has been on targets that did not utilize low density porous materials. This review therefore, attempts to redress this balance and endeavors to review low density materials used in laser plasma experiments in recent years. The emphasis of this review will be on aspects of low density materials that are of relevance to high energy laser plasma experiments. Aspects of low density materials such as densities, elemental compositions, macroscopic structures, nanostructures, and characterization of these materials will be covered. Also, there will be a brief mention of how these aspects affect the results in laser plasma experiments and the constrictions that these requirements put on the fabrication of low density materials relevant to this field. This review is written from the chemists' point of view to aid physicists and the new comers to this field.

Bright x-ray sources from laser irradiation of foams with high concentration of Ti

Energy Technology Data Exchange (ETDEWEB)

Pérez, F., E-mail: perez75@llnl.gov; Patterson, J. R.; May, M.; Colvin, J. D.; Biener, M. M.; Wittstock, A.; Kucheyev, S. O.; Charnvanichborikarn, S.; Satcher, J. H.; Gammon, S. A.; Poco, J. F.; Fournier, K. B. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States); Fujioka, S.; Zhang, Z.; Ishihara, K.; Tanaka, N.; Ikenouchi, T.; Nishimura, H. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-Oka, Suita, Osaka 565-0871 (Japan)

2014-02-15

Low-density foams irradiated by a 20 kJ laser at the Omega laser facility (Laboratory for Laser Energetics, Rochester, NY, USA) are shown to convert more than 5% of the laser energy into 4.6 to 6.0 keV x rays. This record efficiency with foam targets is due to novel fabrication techniques based on atomic-layer-deposition of Ti atoms on an aerogel scaffold. A Ti concentration of 33 at. % was obtained in a foam with a total density of 5 mg/cm{sup 3}. The dynamics of the ionization front through these foams were investigated at the 1 kJ laser of the Gekko XII facility (Institute for Laser Engineering, Osaka, Japan). Hydrodynamic simulations can reproduce the average electron temperature but fail to predict accurately the heat front velocity in the foam. This discrepancy is shown to be unrelated to the possible water adsorbed in the foam but could be attributed to effects of the foam micro-structure.

Experimental demonstration of laser imprint reduction using underdense foams

International Nuclear Information System (INIS)

Delorme, B.; Casner, A.; Olazabal-Loumé, M.; Nicolaï, Ph.; Breil, J.; Tikhonchuk, V. T.; Michel, D. T.; Seka, W.; Froula, D. H.; Goncharov, V.; Riazuelo, G.; Borisenko, N.; Orekhov, A.; Fujioka, S.; Sunahara, A.; Grech, M.

2016-01-01

Reducing the detrimental effect of the Rayleigh-Taylor (RT) instability on the target performance is a critical challenge. In this purpose, the use of targets coated with low density foams is a promising approach to reduce the laser imprint. This article presents results of ablative RT instability growth measurements, performed on the OMEGA laser facility in direct-drive for plastic foils coated with underdense foams. The laser beam smoothing is explained by the parametric instabilities developing in the foam and reducing the laser imprint on the plastic (CH) foil. The initial perturbation pre-imposed by the means of a specific phase plate was shown to be smoothed using different foam characteristics. Numerical simulations of the laser beam smoothing in the foam and of the RT growth are performed with a suite of paraxial electromagnetic and radiation hydrodynamic codes. They confirmed the foam smoothing effect in the experimental conditions.

Experimental demonstration of laser imprint reduction using underdense foams

Energy Technology Data Exchange (ETDEWEB)

Delorme, B.; Casner, A. [CEA, DAM, DIF, F-91297 Arpajon (France); CELIA, University of Bordeaux-CNRS-CEA, F-33400 Talence (France); Olazabal-Loumé, M. [CEA, DAM, CESTA, 15 Avenue des Sablières, F-33114 Le Barp (France); CELIA, University of Bordeaux-CNRS-CEA, F-33400 Talence (France); Nicolaï, Ph.; Breil, J.; Tikhonchuk, V. T. [CELIA, University of Bordeaux-CNRS-CEA, F-33400 Talence (France); Michel, D. T.; Seka, W.; Froula, D. H.; Goncharov, V. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Riazuelo, G. [CEA, DAM, DIF, F-91297 Arpajon (France); Borisenko, N.; Orekhov, A. [P. N. Lebedev Physical Institute, RAS, 53 Leninskii Prospect, Moscow 119991 (Russian Federation); Fujioka, S.; Sunahara, A. [Institute of Laser Engineering, Osaka University, Suita, Osaka 565 (Japan); Grech, M. [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France)

2016-04-15

Reducing the detrimental effect of the Rayleigh-Taylor (RT) instability on the target performance is a critical challenge. In this purpose, the use of targets coated with low density foams is a promising approach to reduce the laser imprint. This article presents results of ablative RT instability growth measurements, performed on the OMEGA laser facility in direct-drive for plastic foils coated with underdense foams. The laser beam smoothing is explained by the parametric instabilities developing in the foam and reducing the laser imprint on the plastic (CH) foil. The initial perturbation pre-imposed by the means of a specific phase plate was shown to be smoothed using different foam characteristics. Numerical simulations of the laser beam smoothing in the foam and of the RT growth are performed with a suite of paraxial electromagnetic and radiation hydrodynamic codes. They confirmed the foam smoothing effect in the experimental conditions.

Rigid Polyurethane Foam Reinforced Coconut Coir Fiber Properties

OpenAIRE

Mohd Azham Azmi

2012-01-01

This research work studied the properties of composite foam panels. Coconut coir fibers were used as reinforcement in polyurethane (PU) foam in order to increase the properties of foam. This composite foam panels were fabricated by using polyurethane molded method. The polyurethane foam panels reinforced from 5 to 20wt% coconut coir were produced to investigate the physical and mechanical test via density test and three point bending test respectively. It was found that the density test resul...

Biopolymer foams - Relationship between material characteristics and foaming behavior of cellulose based foams

International Nuclear Information System (INIS)

Rapp, F.; Schneider, A.; Elsner, P.

2014-01-01

Biopolymers are becoming increasingly important to both industry and consumers. With regard to waste management, CO 2 balance and the conservation of petrochemical resources, increasing efforts are being made to replace standard plastics with bio-based polymers. Nowadays biopolymers can be built for example of cellulose, lactic acid, starch, lignin or bio mass. The paper will present material properties of selected cellulose based polymers (cellulose propionate [CP], cellulose acetate butyrate [CAB]) and corresponding processing conditions for particle foams as well as characterization of produced parts. Special focus is given to the raw material properties by analyzing thermal behavior (differential scanning calorimetry), melt strength (Rheotens test) and molecular weight distribution (gel-permeation chromatography). These results will be correlated with the foaming behavior in a continuous extrusion process with physical blowing agents and underwater pelletizer. Process set-up regarding particle foam technology, including extrusion foaming and pre-foaming, will be shown. The characteristics of the resulting foam beads will be analyzed regarding part density, cell morphology and geometry. The molded parts will be tested on thermal conductivity as well as compression behavior (E-modulus, compression strength)

Biopolymer foams - Relationship between material characteristics and foaming behavior of cellulose based foams

Science.gov (United States)

Rapp, F.; Schneider, A.; Elsner, P.

2014-05-01

Biopolymers are becoming increasingly important to both industry and consumers. With regard to waste management, CO2 balance and the conservation of petrochemical resources, increasing efforts are being made to replace standard plastics with bio-based polymers. Nowadays biopolymers can be built for example of cellulose, lactic acid, starch, lignin or bio mass. The paper will present material properties of selected cellulose based polymers (cellulose propionate [CP], cellulose acetate butyrate [CAB]) and corresponding processing conditions for particle foams as well as characterization of produced parts. Special focus is given to the raw material properties by analyzing thermal behavior (differential scanning calorimetry), melt strength (Rheotens test) and molecular weight distribution (gel-permeation chromatography). These results will be correlated with the foaming behavior in a continuous extrusion process with physical blowing agents and underwater pelletizer. Process set-up regarding particle foam technology, including extrusion foaming and pre-foaming, will be shown. The characteristics of the resulting foam beads will be analyzed regarding part density, cell morphology and geometry. The molded parts will be tested on thermal conductivity as well as compression behavior (E-modulus, compression strength).

Foam separation of Pseudomonas fluorescens and Bacillus subtilis var. niger.

Science.gov (United States)

Grieves, R B; Wang, S L

1967-01-01

An experimental investigation established the effect of the presence of inorganic salts on the foam separation of Pseudomonas fluorescens and of Bacillus subtilis var. niger (B. globigii) from aqueous suspension by use of a cationic surfactant. For P. fluorescens, 5.0 mueq/ml of NaCl, KCl, Na(2)SO(4), K(2)SO(4), CaCl(2), CaSO(4), MgCl(2), or MgSO(4) produced increases in the cell concentration in the residual suspension (not carried into the foam) from 2.9 x 10(5) up to 1.6 x 10(6) to 2.8 x 10(7) cells per milliliter (initial suspensions contain from 3.3 x 10(7) to 4.8 x 10(7) cells per milliliter). The exceptional influence of magnesium was overcome by bringing the cells into contact first with the surfactant and then the salt. For B. subtilis, the presence of 5.0 mueq/ml of any of the eight salts increased the residual cell concentration by one order of magnitude from 1.2 x 10(4) to about 4.0 x 10(5) cells per milliliter. This occurred regardless of the sequence of contact as long as the surfactant contact period was sufficient. The presence of salts increased collapsed foam volumes with P. fluorescens and decreased collapsed foam volumes with B. subtilis.

Macrophage Liver Kinase B1 Inhibits Foam Cell Formation and Atherosclerosis.

Science.gov (United States)

Liu, Zhaoyu; Zhu, Huaiping; Dai, Xiaoyan; Wang, Cheng; Ding, Ye; Song, Ping; Zou, Ming-Hui

2017-10-13

LKB1 (liver kinase B1) is a serine/threonine kinase and tumor suppressor, which regulates the homeostasis of hematopoietic cells and immune responses. Macrophages transform into foam cells upon taking-in lipids. No role for LKB1 in foam cell formation has previously been reported. We sought to establish the role of LKB1 in atherosclerotic foam cell formation. LKB1 expression was examined in human carotid atherosclerotic plaques and in western diet-fed atherosclerosis-prone Ldlr -/- and ApoE -/- mice. LKB1 expression was markedly reduced in human plaques when compared with nonatherosclerotic vessels. Consistently, time-dependent reduction of LKB1 levels occurred in atherosclerotic lesions in western diet-fed Ldlr -/- and ApoE -/- mice. Exposure of macrophages to oxidized low-density lipoprotein downregulated LKB1 in vitro. Furthermore, LKB1 deficiency in macrophages significantly increased the expression of SRA (scavenger receptor A), modified low-density lipoprotein uptake and foam cell formation, all of which were abolished by blocking SRA. Further, we found LKB1 phosphorylates SRA resulting in its lysosome degradation. To further investigate the role of macrophage LKB1 in vivo, ApoE -/- LKB1 fl/fl LysM cre and ApoE -/- LKB1 fl/fl mice were fed with western diet for 16 weeks. Compared with ApoE -/- LKB1 fl/fl wild-type control, ApoE -/- LKB1 fl/fl LysM cre mice developed more atherosclerotic lesions in whole aorta and aortic root area, with markedly increased SRA expression in aortic root lesions. We conclude that macrophage LKB1 reduction caused by oxidized low-density lipoprotein promotes foam cell formation and the progression of atherosclerosis. © 2017 American Heart Association, Inc.

Effects of Kenaf Loading on Processability and Properties of Linear Low-Density Polyethylene/Poly (Vinyl Alcohol/Kenaf Composites

Directory of Open Access Journals (Sweden)

Ai Ling Pang

2015-09-01

Full Text Available This study was conducted to evaluate the possibility of utilizing kenaf (KNF in LLDPE/PVOH to develop a new thermoplastic composite. The effect of KNF loading on the processability and mechanical, thermal and water absorption properties of linear low-density polyethylene/poly (vinyl alcohol/kenaf (LLDPE/PVOH/KNF composites were investigated. Composites with different KNF loadings (0, 10, 20, 30, and 40 phr were prepared using a Thermo Haake Polydrive internal mixer at a temperature of 150 °C and rotor speed of 50 rpm for 10 min. The results indicate that the stabilization torque, tensile modulus, water uptake, and thermal stability increased, while tensile strength and elongation at break decreased with increasing filler loading. The tensile fractured surfaces observed by scanning electron microscopy (SEM supported the deterioration in tensile properties of the LLDPE/PVOH/KNF composites with increasing KNF loading.

CARBONIZED STARCH MICROCELLULAR FOAM-CELLULOSE FIBER COMPOSITE STRUCTURES

Directory of Open Access Journals (Sweden)

Andrew R. Rutledge

2008-11-01

Full Text Available The production of microporous carbon foams from renewable starch microcellular foam-fiber (SMCF-Fiber composites is described. Carbon foams are used in applications such as thermal insulation, battery electrodes, filters, fuel cells, and medical devices. SMCF-Fiber compos-ites were created from an aquagel. The water in the aquagel was exchanged with ethanol and then dried and carbonized. Higher amylose content starches and fiber contents of up to 4% improved the processability of the foam. The SMCF structure revealed agglomerates of swollen starch granules connected by a web of starch with pores in the 50-200 nanometer range. Heating the SMCF-fiber in a nitrogen atmosphere to temperatures between 350-700˚C produced carbon foams with a three-dimensional closed cell foam structure with cell diameters around 50 microns and pore walls around 1-3 microns. The stress versus strain compression data for carbonized samples displayed a linear elastic region and a plateau indicative of brittle crushing, typical of an elastic-brittle foam. The carbon foam products from these renew-able precursors are promising carbon structures with moderate strength and low density.

Graphite Foam Heat Exchangers for Thermal Management

Energy Technology Data Exchange (ETDEWEB)

Klett, J.W.

2004-06-07

Improved thermal management is needed to increase the power density of electronic and more effectively cool electronic enclosures that are envisioned in future aircraft, spacecraft and surface ships. Typically, heat exchanger cores must increase in size to more effectively dissipate increased heat loads, this would be impossible in many cases, thus improved heat exchanger cores will be required. In this Phase I investigation, MRi aimed to demonstrate improved thermal management using graphite foam (Gr-foam) core heat exchangers. The proposed design was to combine Gr-foams from POCO with MRi's innovative low temperature, active metal joining process (S-Bond{trademark}) to bond Gr-foam to aluminum, copper and aluminum/SiC composite faceplates. The results were very favorable, so a Phase II SBIR with the MDA was initiated. This had primarily 5 tasks: (1) bonding, (2) thermal modeling, (3) cooling chip scale packages, (4) evaporative cooling techniques and (5) IGBT cold plate development. The bonding tests showed that the ''reflow'' technique with S-Bond{reg_sign}-220 resulted in the best and most consistent bond. Then, thermal modeling was used to design different chip scale packages and IGBT cold plates. These designs were used to fabricate many finned graphite foam heat sinks specifically for two standard type IC packages, the 423 and 478 pin chips. These results demonstrated several advantages with the foam. First, the heat sinks with the foam were lighter than the copper/aluminum sinks used as standards. The sinks for the 423 design made from foam were not as good as the standard sinks. However, the sinks made from foam for the 478 pin chips were better than the standard heat sinks used today. However, this improvement was marginal (in the 10-20% better regime). However, another important note was that the epoxy bonding technique resulted in heat sinks with similar results as that with the S-bond{reg_sign}, slightly worse than the S

Mechanical properties of tannin-based rigid foams undergoing compression

Energy Technology Data Exchange (ETDEWEB)

Celzard, A., E-mail: Alain.Celzard@enstib.uhp-nancy.fr [Institut Jean Lamour - UMR CNRS 7198, CNRS - Nancy-Universite - UPV-Metz, Departement Chimie et Physique des Solides et des Surfaces, ENSTIB, 27 rue du Merle Blanc, BP 1041, 88051 Epinal cedex 9 (France); Zhao, W. [Institut Jean Lamour - UMR CNRS 7198, CNRS - Nancy-Universite - UPV-Metz, Departement Chimie et Physique des Solides et des Surfaces, ENSTIB, 27 rue du Merle Blanc, BP 1041, 88051 Epinal cedex 9 (France); Pizzi, A. [ENSTIB-LERMAB, Nancy-University, 27 rue du Merle Blanc, BP 1041, 88051 Epinal cedex 9 (France); Fierro, V. [Institut Jean Lamour - UMR CNRS 7198, CNRS - Nancy-Universite - UPV-Metz, Departement Chimie et Physique des Solides et des Surfaces, ENSTIB, 27 rue du Merle Blanc, BP 1041, 88051 Epinal cedex 9 (France)

2010-06-25

The mechanical properties of a new class of extremely lightweight tannin-based materials, namely organic foams and their carbonaceous counterparts are detailed. Scaling laws are shown to describe correctly the observed behaviour. Information about the mechanical characteristics of the elementary forces acting within these solids is derived. It is suggested that organic materials present a rather bending-dominated behaviour and are partly plastic. On the contrary, carbon foams obtained by pyrolysis of the former present a fracture-dominated behaviour and are purely brittle. These conclusions are supported by the differences in the exponent describing the change of Young's modulus as a function of relative density, while that describing compressive strength is unchanged. Features of the densification strain also support such conclusions. Carbon foams of very low density may absorb high energy when compressed, making them valuable materials for crash protection.

Estimation of salt loads for the Dolores River in the Paradox Valley, Colorado, 1980–2015

Science.gov (United States)

Mast, M. Alisa

2017-07-13

Regression models that relate total dissolved solids (TDS) concentrations to specific conductance were used to estimate salt loads for two sites on the Dolores River in the Paradox Valley in western Colorado. The salt-load estimates will be used by the Bureau of Reclamation to evaluate salt loading to the river coming from the Paradox Valley and the effect of the Paradox Valley Unit (PVU), a project designed to reduce the salinity of the Colorado River. A second-order polynomial provided the best fit of the discrete data for both sites on the river. The largest bias occurred in samples with elevated sulfate concentrations (greater than 500 milligrams per liter), which were associated with short-duration runoff events in late summer and fall. Comparison of regression models from a period of time before operation began at the PVU and three periods after operation began suggests the relation between TDS and specific conductance has not changed over time. Net salt gain through the Paradox Valley was estimated as the TDS load at the downstream site minus the load at the upstream site. The mean annual salt gain was 137,900 tons per year prior to operation of the PVU (1980–1993) and 43,300 tons per year after the PVU began operation (1997–2015). The difference in annual salt gain in the river between the pre-PVU and post-PVU periods was 94,600 tons per year, which represents a nearly 70 percent reduction in salt loading to the river.

Experimental Investigation of Properties of Foam Concrete for Industrial Floors in Testing Field

Science.gov (United States)

Vlcek, Jozef; Drusa, Marian; Scherfel, Walter; Sedlar, Bronislav

2017-12-01

Foam concrete (FC), as a mixture of cement, water, additives and technical foam, is well known for more than 30 years. It is building material with good mechanical properties, low thermal conductivity, simple and even high technological treatment. Foam concrete contains closed void pores, what allows achieving low bulk density and spare of raw materials. Thanks to its properties, it is usable as a replacement of conventional subbase layers of the industrial floors, the transport areas or as a part of the foundation structures of the buildings. Paper presents the preparation of the testing field (physical model) which was created for experimental investigation of the foam concrete subbase layer of the industrial floor in a real scale.

Unified Creep Plasticity Damage (UCPD) Model for Rigid Polyurethane Foams.

Energy Technology Data Exchange (ETDEWEB)

Neilsen, Michael K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lu, Wei-Yang [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Scherzinger, William M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hinnerichs, Terry D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lo, Chi S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-06-01

Numerous experiments were performed to characterize the mechanical response of several different rigid polyurethane foams (FR3712, PMDI10, PMDI20, and TufFoam35) to large deformation. In these experiments, the effects of load path, loading rate, and temperature were investigated. Results from these experiments indicated that rigid polyurethane foams exhibit significant volumetric and deviatoric plasticity when they are compressed. Rigid polyurethane foams were also found to be very strain-rate and temperature dependent. These foams are also rather brittle and crack when loaded to small strains in tension or to larger strains in compression. Thus, a new Unified Creep Plasticity Damage (UCPD) model was developed and implemented into SIERRA with the name Foam Damage to describe the mechanical response of these foams to large deformation at a variety of temperatures and strain rates. This report includes a description of recent experiments and experimental findings. Next, development of a UCPD model for rigid, polyurethane foams is described. Selection of material parameters for a variety of rigid polyurethane foams is then discussed and finite element simulations with the new UCPD model are compared with experimental results to show behavior that can be captured with this model.

High performance polymeric foams

International Nuclear Information System (INIS)

Gargiulo, M.; Sorrentino, L.; Iannace, S.

2008-01-01

The aim of this work was to investigate the foamability of high-performance polymers (polyethersulfone, polyphenylsulfone, polyetherimide and polyethylenenaphtalate). Two different methods have been used to prepare the foam samples: high temperature expansion and two-stage batch process. The effects of processing parameters (saturation time and pressure, foaming temperature) on the densities and microcellular structures of these foams were analyzed by using scanning electron microscopy

Redox reaction and foaming in nuclear waste glass melting

Energy Technology Data Exchange (ETDEWEB)

Ryan, J.L.

1995-08-01

This document was prepared by Pacific Northwest Laboratory (PNL) and is an attempt to analyze and estimate the effects of feed composition variables and reducing agent variables on the expected chemistry of reactions occurring in the cold cap and in the glass melt in the nuclear waste glass Slurry-fed, joule-heated melters as they might affect foaming during the glass-making process. Numerous redox reactions of waste glass components and potential feed additives, and the effects of other feed variables on these reactions are reviewed with regard to their potential effect on glass foaming. A major emphasis of this report is to examine the potential positive or negative aspects of adjusting feed with formic acid as opposed to other feed modification techniques including but not limited to use of other reducing agents. Feed modification techniques other than the use of reductants that should influence foaming behavior include control of glass melter feed pH through use of nitric acid. They also include partial replacement of sodium salts by lithium salts. This latter action (b) apparently lowers glass viscosity and raises surface tension. This replacement should decrease foaming by decreasing foam stability.

DRY MIX FOR OBTAINING FOAM CONCRETE

Directory of Open Access Journals (Sweden)

S. N. Leonovich

2015-01-01

Full Text Available Composition of a dry mix has been developed for production of non-autoclaved foam concrete with natural curing. The mix has been created on the basis of Portland cement, UFAPORE foaming agent, mineral additives (RSAM sulfoaluminate additive, MK-85 micro-silica and basalt fiber, plasticizing and accelerating “Citrate-T” additive and   redispersible Vinnapas-8034 H powder. It has been established that foam concrete with  density of 400–800 kg/m3, durability of 1,1–3,4 MPa, low water absorption (40–50 %, without shrinkable cracks has been formed while adding water of Water/Solid = 0.4–0.6 in the dry mix,  subsequent mechanical swelling and curing of foam mass.Introduction of the accelerating and plasticizing “Citrate-T” additive into composition of the dry mix leads to an increase of rheological properties in expanded foam mass and  time reduction of its drying and curing. An investigation on microstructure of foam-concrete chipping surface carried out with the help of a scanning electron microscope has shown that the introduction of  basalt fiber and redispersible Vinnapas-8034 H powder into the composition of the dry mix promotes formation of more finely-divided crystalline hydrates. Such approach makes it possible to change purposefully morphology of crystalline hydrates and gives the possibility to operate foam concrete structurization process.

MECHANICAL STRENGTH ENHANCEMENT OF OPEN-CELL ALUMINA FOAMS USING OPTIMUM CONCENTRATION OF DEFLOCCULANT

Directory of Open Access Journals (Sweden)

A. Hadi

2015-06-01

Full Text Available Open-cell alumina foams were prepared using the appropriate alumina slurry and polyurethane sponge with linear pore density of approximately 14 pores per inch (ppi as a template by the replica method. The rheological studies showed that the optimum solid content for the slurries without deflocculants was 60 wt. %. In order to increase the slurry solid content, Tiron (1,2-dihydroxy-3,5-benzene disulfonic acid disodium salt was used as dispersant. To determine the optimum concentration of dispersant, the viscosity curves of alumina slurries containing different values of Tiron from 0 to 1.2 wt. % (based on dry material weight were studied. The optimum concentration of Tiron obtained for lowest viscosity was 0.8 wt. %. Thus, the solid content in the slurry could be increased from 60 to 66 wt. %. The effect of increase in the slurry solid content and the way it affects the foam structure and the mechanical strength were investigated. Microstructural observations of the foams show a significant reduction in macroscopic and microscopic defects in the foam struts when the slurry solid content is increased. Total porosity of the produced alumina foams prepared using slurries containing 60 and 66 wt. % solid are 83.3 and 80.4 %, respectively, while the compressive strength of the foams has increased from 1.33 to 3.24 MPa.

Study of the effect of gamma irradiation on carbon black loaded low-density polyethylene films

International Nuclear Information System (INIS)

Salem, M.A.; Hussein, A.; El-Ahdal, M.A.

2003-01-01

The effect of gamma irradiation on the tensile and physico-chemical properties of low-density polyethylene (LDPE) films loaded with different concentrations of carbon black (C.B) has been studied. The results showed that the behavior of the samples during gamma irradiation is complicated and this may be due to scission and the interaction between oxidation and crosslinking processes. The tensile properties are modified by the presence of carbon black. Film sample containing 7% C.B was found to exhibit a nearly stabilized tensile behavior with radiation dose, which allows to use this formulation in packaging for food sterilization and in preservation of weak cobalt-gamma sources. (author)

Foam, composition and method of production

Energy Technology Data Exchange (ETDEWEB)

Ghali, R.

1991-09-03

A ternary foam is disclosed which overcomes the disadvantages of conventional heat-insulating foams which are either dense and heavy, expensive to produce, friable, unstable, or have poor fire resistance. The foam of the invention has, by weight of the reaction product, 10-35% polyurethane, 30-55% polyisocyanurate, and 20-45% polyurea. The foam is a reaction product of 100 parts by weight of an organic polyisocyanate with: 15-25 parts by weight of a polyether polyol having a hydroxyl number of ca 28-35 and a molecular weight of not more than 6,000; 5-25 parts by weight of water; 0-25 parts by weight of a blowing agent; 0-50 parts by weight of a filler-plasticizer fire retardant; an effective amount of a low activation catalyst to initiate water-isocyanate reaction to produce polyurea and polyol-isocyanate reaction to produce polyurethane; and an effective amount of a high activation catalyst to retard the low activation catalyst and promote the formation of polyisocyanurate. The low activity catalyst is present in an amount ranging ca 1.5-9 parts per 100 parts by weight of the polyisocyanate, and the high activation catalyst is present in an amount ranging 0.0008-0.002 parts per 100 parts by weight of the polyisocyanate. Water as a reactant and blowing agent can be substituted by an effective amount of a disubstituted amine such as diethanol amine and an inert blowing agent such as fluorocarbon. The resultant foam has excellent heat insulating propeties, is semi-flexible, has a density of 0.5-0.9 lb/ft{sup 3}, and can be inexpensively produced by existing 2-component foam dispensing equipment. 1 fig., 1 tab.

Effect of substrates and intermediate compounds on foaming in manure digestion systems

DEFF Research Database (Denmark)

Boe, Kanokwan; Kougias, Panagiotis; Pacheco, F.

2012-01-01

Manure contains several compounds that can potentially cause foaming during anaerobic digestion. Understanding the effect of substrates and intermediate compounds on foaming tendency and stability could facilitate strategies for foaming prevention and recovery of the process. In this study...... potential to create foam in a manure digester. Moreover, high organic loading of lipids and protein, and high concentrations of acetic and butyric acids also showed a strong tendency to create foaming during anaerobic digestion. Due to their great ability to stabilize foam, high organic loadings of Na...

Spatially resolved density and ionization measurements of shocked foams using x-ray fluorescence

Energy Technology Data Exchange (ETDEWEB)

MacDonald, M. J.; Keiter, P. A.; Montgomery, D. S.; Scott, H. A.; Biener, M. M.; Fein, J. R.; Fournier, K. B.; Gamboa, E. J.; Kemp, G. E.; Klein, S. R.; Kuranz, C. C.; LeFevre, H. J.; Manuel, M. J. -E.; Wan, W. C.; Drake, R. P.

2016-09-28

We present experiments at the Trident laser facility demonstrating the use of x-ray fluorescence (XRF) to simultaneously measure density, ionization state populations, and electron temperature in shocked foams. An imaging x-ray spectrometer obtained spatially resolved measurements of Ti K-α emission. Density profiles were measured from K-α intensity. Ti ionization state distributions and electron temperatures were inferred by fitting K-α spectra to spectra from CRETIN simulations. This work shows that XRF provides a powerful tool to complement other diagnostics to make equation of state measurements of shocked materials containing a suitable tracer element.

Effects of Sintering Temperature on the Density And Porosity of ...

African Journals Online (AJOL)

Effects of sintering temperature on the density and porosity of sodium chloride preforms for alu- minium foam manufacturing have been investigated. Cold pressed salt preforms were sintered at 30, 760 and 790 and di erent times ranging between 6- 18 hours in a carbolite furnace at a heating rate of 5/minute. The Results of ...

Estimation of surface elasticity by the thickness change of liquid film and its correlation with foam stability

Energy Technology Data Exchange (ETDEWEB)

Lim, Jung Ryoul; Park, Jai Koo [Hanyang University, Seoul (Korea, Republic of)

1996-04-30

The relationship between foam stability and surface elasticity by the thickness change of liquid film was investigated. Foam stability was measured by draining liquid volume and decreasing gas volume as a function of time. Foam was formed by the fixed gas-injection the surfactant aqueous solution of different concentration. The used surfactants were sodium lauryl sulfate, hexadecane sulfonic acid sodium salt, and octane sulfonic acid sodium salt. Thickness of liquid film was estimated by using the volume ratio of liquid to gas in foam and surface elasticity of lamella was calculated by the surface tension and adsorbed amount. The thinning of liquid film is due to the combined effects of gravity and capillary suction, it would be ruptured at the minimum of lamella thickness which is called critical thickness. The lamella thickness of bubble which was formed at CMC(critical micelle concentration) was very thin. In the case of sodium lauryl sulfate, the thinning of lamella was continued in the range of measurement. The critical thicknesses of octane sulfonic acid sodium salt solution, hexadecane sulfonic acid sodium salt solution were determined to 0.479{approx}0.316, 0.209{approx}0.200 {mu}m, respectively. It was found that the tendency for foam stability was similar to that of lamella thickness. It was considered that foam which was formed at CMC has very high stability, and the order of foam stability for surfactant aqueous solution was sodium lauryl sulfate > hexadecane sulfonic acid sodium salt > octane sulfonic acid sodium salt. These results was considered that the lamella-rupturing was retarded by the relatively high surface elasticity of lamella. The saturated adsorption of surfactant was determined to 3.25{approx}3.04 * 10{sup -6} mol/m{sup 2} and the surface elasticity of lamella was also determined to 3{approx}56 mN/m. (author). 19 refs., 1 tab., 11 figs.

Effects of livestock species and stocking density on accretion rates in grazed salt marshes

Science.gov (United States)

Nolte, Stefanie; Esselink, Peter; Bakker, Jan P.; Smit, Christian

2015-01-01

Coastal ecosystems, such as salt marshes, are threatened by accelerated sea-level rise (SLR). Salt marshes deliver valuable ecosystem services such as coastal protection and the provision of habitat for a unique flora and fauna. Whether salt marshes in the Wadden Sea area are able to survive accelerated SLR depends on sufficient deposition of sediments which add to vertical marsh accretion. Accretion rate is influenced by a number of factors, and livestock grazing was recently included. Livestock grazing is assumed to reduce accretion rates in two ways: (a) directly by increasing soil compaction through trampling, and (b) indirectly by affecting the vegetation structure, which may lower the sediment deposition. For four years, we studied the impact of two livestock species (horse and cattle) at two stocking densities (0.5 and 1.0 animal ha-1) on accretion in a large-scale grazing experiment using sedimentation plates. We found lower cumulative accretion rates in high stocking densities, probably because more animals cause more compaction and create a lower canopy. Furthermore, a trend towards lower accretion rates in horse-compared to cattle-grazed treatments was found, most likely because (1) horses are more active and thus cause more compaction, and (2) herbage intake by horses is higher than by cattle, which causes a higher biomass removal and shorter canopy. During summer periods, negative accretion rates were found. When the grazing and non-grazing seasons were separated, the impact of grazing differed among years. In summer, we only found an effect of different treatments if soil moisture (precipitation) was relatively low. In winter, a sufficiently high inundation frequency was necessary to create differences between grazing treatments. We conclude that stocking densities, and to a certain extent also livestock species, affect accretion rates in salt marshes. Both stocking densities and livestock species should thus be taken into account in management

Materials Applications for Non-Lethal: Aqueous Foams

Energy Technology Data Exchange (ETDEWEB)

GOOLSBY,TOMMY D.; SCOTT,STEVEN H.

1999-09-15

be seriously injured during violent confrontations. The very low density of the high expansion foam also makes it more suitable for indoor use. This paper summarizes the results of the project.

Materials Applications for Non-Lethal: Aqueous Foams

International Nuclear Information System (INIS)

GOOLSBY, TOMMY D.; SCOTT, STEVEN H.

1999-01-01

seriously injured during violent confrontations. The very low density of the high expansion foam also makes it more suitable for indoor use. This paper summarizes the results of the project

1-D Van der Waals Foams Heated by Ion Beam Energy Deposition

International Nuclear Information System (INIS)

Zylstra, A.B.; Barnard, J.J.; More, R.M.

2009-01-01

One dimensional simulations of various initial average density aluminum foams (modeled as slabs of solid metal separated by low density regions) heated by volumetric energy deposition are conducted with a Lagrangian hydrodynamics code using a van der Waals equation of tate (EOS). The resulting behavior is studied to facilitate the design of future warm dense matter (WDM) experiments at LBNL. In the simulations the energy deposition ranges from 10 to 30 kJ/g and from 0.075 to 4.0 ns total pulse length, resulting in temperatures from approximately 1 o 4 eV. We study peak pressures and temperatures in the foams, expansion velocity, and the phase evolution. Five relevant time scales in the problem are identified. Additionally, we present a method for characterizing the level of inhomogeneity in a foam target as it is heated and the time it takes for a foam to homogenize.

Ni-Pd-Al2O3 catalyst supported on reticulated ceramic foam for dry methane reforming

Directory of Open Access Journals (Sweden)

Vesna Nikolić

2015-03-01

Full Text Available In the present study, Ni-Pd/Al2O3 catalyst supported on α-Al2O3 based foam was prepared and evaluated in the dry methane reforming process. Corresponding metal chlorides were deposited to the foam surface by impregnation of the foam with ultrasonically aerosolized salt solutions at 473 K and drying at that temperature. Calcination step was excluded and the catalyst was reduced at very low temperature – 533 K. The reforming experiment lasted for 3 h, with standing time of 1 h at the following temperatures: 873, 973 and 1023 K. Conclusions on selectivity, catalytic activity and stability were reached on the basis of CO and H2 yields.

Applications of Foamed Lightweight Concrete

Directory of Open Access Journals (Sweden)

Mohd Sari Kamarul Aini

2017-01-01

Full Text Available Application of foamed concrete is increasing at present due to high demand on foamed concrete structures with good mechanical and physical properties. This paper discusses on the use of basic raw materials, their characteristics, production process, and their application in foamed lightweight concrete with densities between 300 kg/m3 and 1800 kg/m3. It also discusses the factors that influence the strengths and weaknesses of foamed concrete based on studies that were conducted previously.

Effect of oral salt loading on blood pressure and lymphocyte sodium metabolism in borderline hypertension

DEFF Research Database (Denmark)

Pedersen, K E; Jest, P; Klitgaard, N A

1986-01-01

A randomized double-blind cross-over trial was performed to test the effects of oral salt loading (normal diet + 200 mmol NaCl/day for 4 weeks followed by normal diet + 400 mmol/day for 1 week) against placebo on blood pressure and lymphocyte sodium homeostasis in 10 young borderline hypertensive...... men, genetically predisposed for essential hypertension. Salt loading caused no significant changes in blood pressure levels, lymphocyte sodium content and efflux. In conclusion, our subjects seem insensitive to a few weeks of excessive salt intake....

Industrial waste utilization for foam concrete

Science.gov (United States)

Krishnan, Gokul; Anand, K. B.

2018-02-01

Foam concrete is an emerging and useful construction material - basically a cement based slurry with at least 10% of mix volume as foam. The mix usually containing cement, filler (usually sand) and foam, have fresh densities ranging from 400kg/m3 to 1600kg/m3. One of the main drawbacks of foam concrete is the large consumption of fine sand as filler material. Usage of different solid industrial wastes as fillers in foam concrete can reduce the usage of fine river sand significantly and make the work economic and eco-friendly. This paper aims to investigate to what extent industrial wastes such as bottom ash and quarry dust can be utilized for making foam concrete. Foam generated using protein based agent was used for preparing and optimizing (fresh state properties). Investigation to find the influence of design density and air-void characteristics on the foam concrete strength shows higher strength for bottom ash mixes due to finer air void distribution. Setting characteristics of various mix compositions are also studied and adoption of Class C flyash as filler demonstrated capability of faster setting.

Where Does Road Salt Go - a Static Salt Model

Science.gov (United States)

Yu, C. W.; Liu, F.; Moriarty, V. W.

2017-12-01

Each winter, more than 15 million tons of road salt is applied in the United States for the de-icing purpose. Considerable amount of chloride in road salt flows into streams/drainage systems with the snow melt runoff and spring storms, and eventually goes into ecologically sensitive low-lying areas in the watershed, such as ponds and lakes. In many watersheds in the northern part of US, the chloride level in the water body has increased significantly in the past decades, and continues an upward trend. The environmental and ecological impact of the elevated chloride level can no longer be ignored. However although there are many studies on the biological impact of elevated chloride levels, there are few investigations on how the spatially distributed road salt application affects various parts of the watershed. In this presentation, we propose a static road salt model as a first-order metric to address spacial distribution of salt loading. Derived from the Topological Wetness Index (TWI) in many hydrological models, this static salt model provides a spatial impact as- sessment of road salt applications. To demonstrate the effectiveness of the static model, National Elevation Dataset (NED) of ten-meter resolution of Lake George watershed in New York State is used to generate the TWI, which is used to compute a spatially dis- tributed "salt-loading coefficient" of the whole watershed. Spatially varying salt applica- tion rate is then aggregated, using the salt-loading coefficients as weights, to provide salt loading assessments of streams in the watershed. Time-aggregated data from five CTD (conductivity-temperature-depth) sensors in selected streams are used for calibration. The model outputs and the sensor data demonstrate a strong linear correlation, with the R value of 0.97. The investigation shows that the static modeling approach may provide an effective method for the understanding the input and transport of road salt to within watersheds.

Direct sputtering- and electro-deposition of gold coating onto the closed surface of ultralow-density carbon-hydrogen foam cylinder

Energy Technology Data Exchange (ETDEWEB)

Luo, Jiaqiu; Yin, Jialing; Zhang, Hao; Yao, Mengqi; Hu, Wencheng, E-mail: huwc@uestc.edu.cn

2016-12-15

Highlights: • The surface pores of P(DVB/St) foam cylinder are sealed by CVD method. • Gold film was deposited on the surface of foam cylinder by magnetron sputtering. • Electroless plating was excluded in the present experiments. • The gold coatings were thickened through the electrodeposition process. - Abstract: This work aimed to fabricate a gold coating on the surface of ultralow-density carbon-hydrogen foam cylinder without electroless plating. Poly (divinylbenzene/styrene) foam cylinder was synthetized by high internal phase emulsion, and chemical vapor deposition polymerization approach was used to form a compact poly-p-xylylene film on the foam cylinder. Conducting gold thin films were directly deposited onto the poly-p-xylylene-modified foam cylinder by magnetron sputtering, and electrochemical deposition was adopted to thicken the gold coatings. The micro-structures and morphologies of poly (divinylbenzene/styrene) foam cylinder and gold coating were observed by field-emission scanning electron microscopy. The gold coating content was investigated by energy-dispersive X-ray. The thicknesses of poly-p-xylylene coating and sputtered gold thin-film were approximately 500 and 100 nm, respectively. After electrochemical deposition, the thickness of gold coating increased to 522 nm, and the gold coating achieved a compact and uniform structure.

Influence of the glass-calcium carbonate mixture's characteristics on the foaming process and the properties of the foam glass

DEFF Research Database (Denmark)

König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

2014-01-01

We prepared foam glasses from cathode-ray-tube panel glass and CaCO3 as a foaming agent. We investigated the influences of powder preparation, CaCO3 concentration and foaming temperature and time on the density, porosity and homogeneity of the foam glasses. The results show that the decomposition...

Rate Dependence of the Compressive Response of Ti Foams

Directory of Open Access Journals (Sweden)

Nik Petrinic

2012-06-01

Full Text Available Titanium foams of relative density ranging from 0.3 to 0.9 were produced by titanium powder sintering procedures and tested in uniaxial compression at strain rates ranging from 0.01 to 2,000 s−1. The material microstructure was examined by X-ray tomography and Scanning Electron Microscopy (SEM observations. The foams investigated are strain rate sensitive, with both the yield stress and the strain hardening increasing with applied strain rate, and the strain rate sensitivity is more pronounced in foams of lower relative density. Finite element simulations were conducted modelling explicitly the material’s microstructure at the micron level, via a 3D Voronoi tessellation. Low and high strain rate simulations were conducted in order to predict the material’s compressive response, employing both rate-dependant and rate-independent constitutive models. Results from numerical analyses suggest that the primary source of rate sensitivity is represented by the intrinsic sensitivity of the foam’s parent material.

Mechanical characterization of hybrid and functionally-graded aluminum open-cell foams with nanocrystalline-copper coatings

Science.gov (United States)

Sun, Yi

Cellular/foam materials found in nature such as bone, wood, and bamboo are usually functionally graded by having a non-uniform density distribution and inhomogenous composition that optimizes their global mechanical performance. Inspired by such naturally engineered products, the current study was conducted towards the development of functionally graded hybrid metal foams (FGHMF) with electrodeposited (ED) nanocrystalline coatings. First, the deformation and failure mechanisms of aluminum/copper (Al/Cu) hybrid foams were investigated using finite element analyses at different scales. The micro-scale behavior was studied based on single ligament models discretized using continuum elements and the macro-scale behavior was investigated using beam-element based finite element models of representative unit volumes consisting of multiple foam cells. With a detailed constitutive material behavior and material failure considered for both the aluminum ligament and the nano-copper coating, the numerical models were able to capture the unique behavior of Al/Cu hybrid foams, such as the typically observed sudden load drop after yielding. The numerical models indicate that such load drop is caused by the fracture of foam ligaments initiated from the rupture of the ED nano-copper coating due to its low ductility. This failure mode jeopardizes the global energy absorption capacity of hybrid foams, especially when a thick coating is applied. With the purpose of enhancing the performance of Al/Cu hybrid foams, an annealing process, which increased the ductility of the nanocrystalline copper coating by causing recovery, recrystallination and grain growth, was introduced in the manufacturing of Al/Cu hybrid foams. Quasi-static experimental results indicate that when a proper amount of annealing is applied, the ductility of the ED copper can be effectively improved and the compressive and tensile behavior of Al/Cu hybrid foams can be significantly enhanced, including better energy

Preparation of three-dimensional shaped aluminum alloy foam by two-step foaming

International Nuclear Information System (INIS)

Shang, J.T.; Xuming, Chu; Deping, He

2008-01-01

A novel method, named two-step foaming, was investigated to prepare three-dimensional shaped aluminum alloy foam used in car industry, spaceflight, packaging and related areas. Calculations of thermal decomposition kinetics of titanium hydride showed that there is a considerable amount of hydrogen releasing when the titanium hydride is heated at a relatively high temperature after heated at a lower temperature. The hydrogen mass to sustain aluminum alloy foam, having a high porosity, was also estimated by calculations. Calculations indicated that as-received titanium hydride without any pre-treatment can be used as foaming agents in two-step foaming. The processes of two-step foaming, including preparing precursors and baking, were also studied by experiments. Results showed that, low titanium hydride dispersion temperature, long titanium hydride dispersion time and low precursors porosity are beneficial to prepare three-dimensional shaped aluminum alloy foams with uniform pores

CFC alternatives for thermal insulation foams

Energy Technology Data Exchange (ETDEWEB)

Shankland, I.R. (Allied-Signal Inc., Buffalo, NY (US))

1990-03-01

Low density polymeric foam materials expanded with chlorofluorocarbon (CFC) blowing agents have found widespread use as highly efficient thermal insulation materials in the construction, refrigeration appliance and transportation industries. The advent of regulations which are reducing the production and consumption of the fully halogenated CFCs for environmental reasons has prompted the development of environmentally acceptable substitutes for the CFC blowing agents. This paper summarizes the physical properties and performance of the leading alternatives for CFC-11, which is used to expand rigid polyurethane and polyisocyanurate foams, and the leading alternatives for CFC-12 which is used to expand extruded polystyrene board foam. Although the alternatives, HCFC-123 and HCFC-14lb for CFC-11 and HCFC142b and HCFC-124 for CFC-12, are not perfect matches from the performance viewpoint, they represent the optimum choice given the constraints on environmental acceptability, toxicity, flammability and performance. (author).

Rigid Polyurethane Foam Thermal Insulation Protected with Mineral Intumescent Mat

Directory of Open Access Journals (Sweden)

Kirpluks Mikelis

2014-12-01

Full Text Available One of the biggest disadvantages of rigid polyurethane (PU foams is its low thermal resistance, high flammability and high smoke production. Greatest advantage of this thermal insulation material is its low thermal conductivity (λ, which at 18-28 mW/(m•K is superior to other materials. To lower the flammability of PU foams, different flame retardants (FR are used. Usually, industrially viable are halogenated liquid FRs but recent trends in EU regulations show that they are not desirable any more. Main concern is toxicity of smoke and health hazard form volatiles in PU foam materials. Development of intumescent passive fire protection for foam materials would answer problems with flammability without using halogenated FRs. It is possible to add expandable graphite (EG into PU foam structure but this increases the thermal conductivity greatly. Thus, the main advantage of PU foam is lost. To decrease the flammability of PU foams, three different contents 3%; 9% and 15% of EG were added to PU foam formulation. Sample with 15% of EG increased λ of PU foam from 24.0 to 30.0 mW/(m•K. This paper describes the study where PU foam developed from renewable resources is protected with thermally expandable intumescent mat from Technical Fibre Products Ltd. (TFP as an alternative to EG added into PU material. TFP produces range of mineral fibre mats with EG that produce passive fire barrier. Two type mats were used to develop sandwich-type PU foams. Also, synergy effect of non-halogenated FR, dimethyl propyl phosphate and EG was studied. Flammability of developed materials was assessed using Cone Calorimeter equipment. Density, thermal conductivity, compression strength and modulus of elasticity were tested for developed PU foams. PU foam morphology was assessed from scanning electron microscopy images.

A constitutive model for the compressive response of metallic closed-cell foams including micro-inertia effects

Directory of Open Access Journals (Sweden)

Barthélémy Romain

2015-01-01

Full Text Available Metallic foams have known a keen interest in the last decades. Their ability to undergo very large deformations while transmitting low stress levels make them capable of performing functions of protective layers against intense loadings and of energy absorbers, for instance. The behaviour of metal foams varies considerably between quasi-static and dynamic regimes. Those differences can be linked to the strain-rate sensitivity of the skeleton material and to micro-inertial effects (induced by the crushing of the foam cells. In the present work, a micromechanical model has been developed to take into account micro-inertia effects on the macroscopic behaviour of closed-cell foams under dynamic loading conditions. The proposed modelling is based on the dynamic homogenisation procedure introduced by Molinari and Mercier (J. Mech. Phys. Solids 49 (2001 1497–1516. Within this framework, the macrostress is the sum of two terms. The first one is a static stress, that can be described with any existing model of metal foam. The second contribution is a dynamic stress related to micro-inertia effects. Considering an initially spherical shell as a Representative Volume Element (RVE of the foam material, a closed-form expression of the dynamic stress was obtained. The proposed modelling was applied to shock propagation in aluminium foams (it should however be noted that the present theory is not restricted to uniaxial deformation but can be applied to arbitrary loadings. From experimental data of the literature, it is observed that incorporating micro-inertia effects allows one to achieve a better description of the foam shock response. This indicates that micro-inertia may have a significant influence on the dynamic behaviour of metallic foams.

Supercapacitors based on carbon foams

Science.gov (United States)

Kaschmitter, James L.; Mayer, Steven T.; Pekala, Richard W.

1993-01-01

A high energy density capacitor incorporating a variety of carbon foam electrodes is described. The foams, derived from the pyrolysis of resorcinol-formaldehyde and related polymers, are high density (0.1 g/cc-1.0 g/cc) electrically conductive and have high surface areas (400 m.sup.2 /g-1000 m.sup.2 /g). Capacitances on the order of several tens of farad per gram of electrode are achieved.

Development of foams from linear polypropylene (PP) and high melt strength polypropylene (HMSPP) polymeric blends

International Nuclear Information System (INIS)

Cardoso, Elisabeth Carvalho Leite

2009-01-01

Foamed polymers are future materials, with a comprehensive application field. They can be used in order to improve appearance of insulation structures, for example, or to reduce costs involving materials. This work address to Isotactic Polypropylene / High Melt Strength Polypropylene blends, for foams production. Rheological behavior of polymer melt, especially referring to viscosity in processing temperature, plays a decisive role in applications where dominates extensional flow, as in case of foaming. If the viscosity is very low, it will correspond to a low melt strength, as in case of linear homopolymer (Isotact PP), and the foam will be prejudiced, due to the impossibility of expansion. Otherwise, if the viscosity is very high, with a high melt strength, the foam will collapse immediately after its formation. In order to get foams with an homogeneous and defined cellular structure, there were accomplished blends, 50% in weight, between linear homopolymer (isotactic PP) and HMSPP, from PP modified as per gamma radiation, in acetylene environment and at a 12.5 kGy doses. Extrusion process used a soluble foaming methodology, according to a processing/dissolution principle, which involves the dissolution of a Physical Blowing Agent (PBA), under 30 bar pressure, homogeneously mixed with polymeric melt. Extrusion conditions, that generally involve temperature, pressure and viscoelastic material flow control were experimentally investigated to define prevalent characteristics for producing foams. Nitrogen was the used PBA and process extrusion parameters were adapted to PP, HMSPP and their 50% in weight mixtures thereof. Major PP and HMSPP characteristics were obtained via melt Index and melt strength and thermal analyses (DSC/TGA), in order to make viable and to reproduce foaming as per extrusion process. Foams cellular morphology of PP, HMSPP and their 50% in weight mixtures thereof was investigated, with and without talc addition, as nucleating agent, by using

Design and evaluation of a foam-filled hat-stiffened panel concept for aircraft primary structural applications

Science.gov (United States)

Ambur, Damodar R.

1995-01-01

A structurally efficient hat-stiffened panel concept that utilizes a structural foam as stiffener core has been designed for aircraft primary structural applications. This stiffener concept utilizes a manufacturing process that can be adapted readily to grid-stiffened structural configurations which possess inherent damage tolerance characteristics due to their multiplicity of load paths. The foam-filled hat-stiffener concept in a prismatically stiffened panel configuration is more efficient than most other stiffened panel configurations in a load range that is typical for both fuselage and wing structures. The prismatically stiffened panel concept investigated here has been designed using AS4/3502 preimpregnated tape and Rohacell foam core and evaluated for its buckling and postbuckling behavior with and without low-speed impact damage. The results from single-stiffener and multi-stiffener specimens suggest that this structural concept responds to loading as anticipated and has good damage tolerance characteristics.

Study of the characterization of crosslinking polyethylene foam by irradiation process with electron beam

International Nuclear Information System (INIS)

Dias, Djalma Batista

2007-01-01

The polyethylene foams are widely used. Their main applications are used for both home appliances to medical equipment. Beside that, they have applications in building and automotive industries. The foam properties depend on the density and its cellular structure, that is, the amount of open and closed cells, of the distribution and size of them. The methods of the crosslinking polyethylene foam production are classified in two types, according to the crosslinking method. One method is based on the chemical crosslinking, which utilizes peroxide as crosslinking agent. In the other method, the crosslinking is induced by electron beam radiation. The foams obtained from the crosslinking polyethylene by irradiation process presented a smooth and the homogeneous surface, and are formed basically by closed cells. The aim of this study was to apply the ionizing radiation from electron beam to crosslink low density polyethylene (LDPE), to obtain foams. Their morphological, thermal and mechanical properties were studied to evaluate the obtained samples. The samples of low density polyethylene (0,946 g/cm 3 ), containing 5% of azodicarbonamide (ADCA), as expander agent, were irradiated with electron beam with doses of 10, 20, 30, 40, 50, 60, 80 and 100 kGy. After the irradiation, these LDPE samples were put into an oven to obtain the foams. It was determined the crosslinking degree of the foams. Some samples were also thermally aged. The mechanical performance of the foams samples was evaluated by means of the tensile strength, compression, hardness, permanent deformation by compression and resilience. It was also carried out thermogravimetry and scanning electron microscopy (SEM). The results have shown that, in the interval of radiation doses studied, that the tensile strength increases with the increase of the crosslinking degree. The compression resistance results obtained from with samples with to radiation dose of 40 kGy showed significant decreasing. The resilience

Highly porous open cell Ti-foam using NaCl as temporary space holder through powder metallurgy route

International Nuclear Information System (INIS)

Jha, Nidhi; Mondal, D.P.; Dutta Majumdar, J.; Badkul, Anshul; Jha, A.K.; Khare, A.K.

2013-01-01

Highlights: ► NaCl crystals has been used as space holder. ► Variation of NaCl:Ti ratio varies porosity (65–80%). ► NaCl is cubic but the cells are spherical. ► Two types of pores: micro and macro pores are obtained. ► Foams are suitable for bones scaffolds and engineering applications. - Abstract: Open cell Titanium-foam (Ti-foam) with varying porosities (65–80%) was prepared using sodium chloride (NaCl) particles as space holder through powder metallurgy route. In order to ensure sufficient handling strength in cold compacted pallets, 2 wt.% polyvinyl alcohol (PVA) solutions (5 wt.% PVA in water) was mixed with the mixture of Ti and NaCl powders prior to cold compaction. After sintering, NaCl salt was removed by dissolving it in hot water. Detailed Energy dispersive X-ray (EDX) analysis and X-ray diffraction studies of the prepared Ti-foams were conducted to examine any physical and chemical changes in the phase constituents. The micro-architectural characteristics, density vis-a-vis porosity, and compressive deformation behavior of the synthesized foams were evaluated to examine their suitability as biomaterial and engineering applications

Use of urethane foam in preparing for decontamination and decommissioning of radioactive facilities

International Nuclear Information System (INIS)

1981-01-01

Portable urethane foam generating equipment has been in use for 15 to 20 years for a large number of applications, such as roof systems, tank insulation, and building insulation. Still another industrial application is its use in the decontamination and decommissioning of radioactive facilities at Mound Facility. The major problems encountered with urethane foams were with the packaging and stabilization procedures. The operation for spraying the foam on interior surfaces and equipment involved getting the gun inside without opening up the interior to the outside environment. A Gusmer FF proportioner and Model D spray gun was used for this operation. The gun was modified so that the trigger could be remotely located to facilitate its entry through a glovebox gloveport opening. The Model D gun has an air cap to blow foam off the tip of the gun. This cap was used to hold a plastic bag in place around the gun. The plastic bag is then put on a glove port and fastened securely. Urethane spray is applied on all exposed surfaces. This assures that all residual material is fixed for shipment. This simplifies cleaning operations as there is no need to remove the last trace of plutonium and results in a considerable shortening of the time required to prepare the gloveboxes. With the interior foamed, the gloveboxes are moved to the loading and packaging areas. Urethane foams are used to fill in the voids in our final shipping container. Radioactive waste materials are segregated according to the level of radioactive material present. One category is low level or low specific activity (LSA) and the other high level or Transuranic (TRU). Foam is used in TRU packages as packaging material to stabilize the loads and to help cushion against shock in transit on truck or railcar

Low Bone Density

Science.gov (United States)

... Density Exam/Testing › Low Bone Density Low Bone Density Low bone density is when your bone density ... people with normal bone density. Detecting Low Bone Density A bone density test will determine whether you ...

Preparation and characterization of starch-based loose-fill packaging foams

Science.gov (United States)

Fang, Qi

Regular and waxy corn starches were blended in various ratios with biodegradable polymers including polylactic acid (PLA), Eastar Bio Copolyester 14766 (EBC) and Mater-Bi ZF03U (MBI) and extruded with a C. W. Brabender laboratory twin screw extruder using a 3-mm die nozzle at 150°C and 150 rev/min. Physical characteristics including radial expansion, unit density and bulk density and water solubility index, water absorption characteristics, mechanical properties including compressibility, Young's modulus, spring index, bulk compressibility and bulk spring index and abrasion resistance were investigated as affected by the ingredient formulations, i.e. type of polymers, type of starches, polymer to starch ratio and starch moisture content. A completely randomized factorial blocking experimental design was used. Fifty-four treatments resulted. Each treatment was replicated three times. SAS statistical software package was used to analyze the data. Foams made of waxy starch had better radial expansion, lower unit density and bulk density than did foams made of regular starch. Regular starch foams had significantly lower water solubility index than did the waxy starch foams. PLA-starch foams had the lowest compressibility and Young's modulus. MBI-starch foams were the most rigid. All foams had excellent spring indices and bulk spring indices which were comparable to the spring index of commercial expanded polystyrene foam. Correlations were established between the foam mechanical properties and the physical characteristics. Foam compressibility and Young's modulus decreased as increases in radial expansion and decreases in unit and bulk densities. Their relationships were modeled with power law equations. No correlation was observed between spring index and bulk spring index and foam physical characteristics. MBI-starch foams had the highest equilibrium moisture content. EBC-starch and PLA-starch foams had similar water absorption characteristics. No significant

Foaming in manure based digesters: Effect of overloading and foam suppression using antifoam agents

DEFF Research Database (Denmark)

Kougias, Panagiotis; Tsapekos, Panagiotis; Boe, Kanokwan

Anaerobic digestion foaming is one of the major problems that occasionally occur in full-scale biogas plants, affecting negatively the overall digestion process. The foam is typically created either in the main biogas reactor or/and in the pre-storage tank and the entrapped solids in the foam cause...... severe operational problems, such as blockage of mixing devices and collapse of pumps. Furthermore, the foaming problem is linked with economic consequences for biogas plants, due to income losses derived from the reduced biogas production, extra labour work and additional maintenance costs. Moreover....... A continuous stirred tank reactor, operating under thermophilic conditions (55 oC) was fed with cattle manure. In order to investigate the effect of organic overloading on foam formation, a stepwise increase of the organic loading rate was performed by the addition of glucose in the feeding substrate. Biogas...

Transient coupled calculations of the Molten Salt Fast Reactor using the Transient Fission Matrix approach

Energy Technology Data Exchange (ETDEWEB)

Laureau, A., E-mail: laureau.axel@gmail.com; Heuer, D.; Merle-Lucotte, E.; Rubiolo, P.R.; Allibert, M.; Aufiero, M.

2017-05-15

Highlights: • Neutronic ‘Transient Fission Matrix’ approach coupled to the CFD OpenFOAM code. • Fission Matrix interpolation model for fast spectrum homogeneous reactors. • Application for coupled calculations of the Molten Salt Fast Reactor. • Load following, over-cooling and reactivity insertion transient studies. • Validation of the reactor intrinsic stability for normal and accidental transients. - Abstract: In this paper we present transient studies of the Molten Salt Fast Reactor (MSFR). This generation IV reactor is characterized by a liquid fuel circulating in the core cavity, requiring specific simulation tools. An innovative neutronic approach called “Transient Fission Matrix” is used to perform spatial kinetic calculations with a reduced computational cost through a pre-calculation of the Monte Carlo spatial and temporal response of the system. Coupled to this neutronic approach, the Computational Fluid Dynamics code OpenFOAM is used to model the complex flow pattern in the core. An accurate interpolation model developed to take into account the thermal hydraulics feedback on the neutronics including reactivity and neutron flux variation is presented. Finally different transient studies of the reactor in normal and accidental operating conditions are detailed such as reactivity insertion and load following capacities. The results of these studies illustrate the excellent behavior of the MSFR during such transients.

Transient coupled calculations of the Molten Salt Fast Reactor using the Transient Fission Matrix approach

International Nuclear Information System (INIS)

Laureau, A.; Heuer, D.; Merle-Lucotte, E.; Rubiolo, P.R.; Allibert, M.; Aufiero, M.

2017-01-01

Highlights: • Neutronic ‘Transient Fission Matrix’ approach coupled to the CFD OpenFOAM code. • Fission Matrix interpolation model for fast spectrum homogeneous reactors. • Application for coupled calculations of the Molten Salt Fast Reactor. • Load following, over-cooling and reactivity insertion transient studies. • Validation of the reactor intrinsic stability for normal and accidental transients. - Abstract: In this paper we present transient studies of the Molten Salt Fast Reactor (MSFR). This generation IV reactor is characterized by a liquid fuel circulating in the core cavity, requiring specific simulation tools. An innovative neutronic approach called “Transient Fission Matrix” is used to perform spatial kinetic calculations with a reduced computational cost through a pre-calculation of the Monte Carlo spatial and temporal response of the system. Coupled to this neutronic approach, the Computational Fluid Dynamics code OpenFOAM is used to model the complex flow pattern in the core. An accurate interpolation model developed to take into account the thermal hydraulics feedback on the neutronics including reactivity and neutron flux variation is presented. Finally different transient studies of the reactor in normal and accidental operating conditions are detailed such as reactivity insertion and load following capacities. The results of these studies illustrate the excellent behavior of the MSFR during such transients.

Hairy foam" : carbon nanofibers grown on solid foam. A fully accessible, high surface area, graphitic catalyst support

NARCIS (Netherlands)

Wenmakers, P.W.A.M.; Schaaf, van der J.; Kuster, B.F.M.; Schouten, J.C.

2008-01-01

This paper describes the synthesis of carbon nanofibers (CNFs) on solid carbon foam ("Hairy Foam") by catalytic decompn. of ethylene. The effect of nickel loading on fiber diam. and morphol., CNF coverage, and fiber layer thickness is studied using SEM and N2/Kr-physisorption. The surface area

Hemodynamic responses to mental stress during salt loading

DEFF Research Database (Denmark)

Goyal, Maria Gefke; Christensen, Niels Juel; Bech, Per

2017-01-01

) during preparation for a medical exam (prolonged stress) and (ii) outside the exam period (low stress). All subjects consumed a controlled diet for 3 days with low- or high-salt content in randomized order. The subjective stress was measured by Spielberger's State-Trait Anxiety Inventory-Scale, SCL......, CO as well as plasma levels of NE, E and PRA remained unchanged by changes in stress level. Day-night reduction in SAP was significantly larger during moderate stress and high-salt intake; however, no significant difference was observed during daytime and night-time. Individual increase in mental...

Sands subjected to repetitive vertical loading under zero lateral strain: accumulation models, terminal densities, and settlement

KAUST Repository

Chong, Song Hun

2016-08-09

Geosystems often experience numerous loading cycles. Plastic strain accumulation during repetitive mechanical loads can lead to shear shakedown or continued shear ratcheting; in all cases, volumetric strains diminish as the specimen evolves towards terminal density. Previously suggested models and new functions are identified to fit plastic strain accumulation data. All accumulation models are formulated to capture terminal density (volumetric strain) and either shakedown or ratcheting (shear strain). Repetitive vertical loading tests under zero lateral strain conditions are conducted using three different sands packed at initially low and high densities. Test results show that plastic strain accumulation for all sands and density conditions can be captured in the same dimensionless plot defined in terms of the initial relative density, terminal density, and ratio between the amplitude of the repetitive load and the initial static load. This observation allows us to advance a simple but robust procedure to estimate the maximum one-dimensional settlement that a foundation could experience if subjected to repetitive loads. © 2016, Canadian Science Publishing. All rights reserved.

Investigation of Energy Absorption in Aluminum Foam Sandwich Panels By Drop Hammer Test: Experimental Results

Directory of Open Access Journals (Sweden)

Mohammad Nouri Damghani

2016-05-01

Full Text Available The sandwich panel structures with aluminum foam core and metal surfaces have light weight with high performance in dispersing energy. This has led to their widespread use in the absorption of energy. The cell structure of foam core is subjected to plastic deformation in the constant tension level that absorbs a lot of kinetic energy before destruction of the structure. In this research, by making samples of aluminum foam core sandwich panels with aluminum surfaces, experimental tests of low velocity impact by a drop machine are performed for different velocities and weights of projectile on samples of sandwich panels with aluminum foam core with relative density of 18%, 23%, and 27%. The output of device is acceleration‐time diagram which is shown by an accelerometer located on the projectile. From the experimental tests, the effect of weight, velocity and energy of the projectile and density of the foam on the global deformation, and energy decrease rate of projectile have been studied. The results of the experimental testes show that by increasing the density of aluminum foam, the overall impression is reduced and the slop of energy loss of projectile increases. Also by increasing the velocity of the projectile, the energy loss increases.

Foamed concrete containing rice husk ash as sand replacement: an experimental study on compressive strength

Science.gov (United States)

Rum, R. H. M.; Jaini, Z. M.; Boon, K. H.; Khairaddin, S. A. A.; Rahman, N. A.

2017-11-01

This study presents the utilization of rice husk ash (RHA) as sand replacement in foamed concrete. The study focuses on the effect of RHA on the compressive strength of foamed concrete. RHA contains high pozzolanic material that reacts with cementitious to enhance the strength and durability of foamed concrete. RHA also acts as filler causing the foamed concrete to become denser while retaining its unique low density. A total 243 cube specimens was prepared for the compression test. Two sets of mix design were employed at water-cement (W/C) ratio of 0.55, 0.60 and cement-sand ratio of 0.50, 0.33. The results revealed that the presence of RHA as sand replacement resulted in an increase in the compressive strength of foamed concrete. Moreover, 30% to 40% RHA was the optimum content level, contributing to the compressive strength of 18.1 MPa to 22.4 MPa. The W/C ratio and superplasticiser dosage play small roles in improving workability. In contrast, density governs the compressive strength of foamed concrete.

Experimental Investigation into Pull-Out Strength of Foamed Concrete Using Different Types of Screw

Directory of Open Access Journals (Sweden)

Othuman Mydin M.A.

2014-01-01

Full Text Available This study focuses on the results of the comprehensive strength test to quantify the mechanical properties of the screw’s pullout strength on foamed concrete. Foamed concrete is classified as lightweight concrete that been produced by cement paste or mortar in which air-voids are entrapped in the mortar by a suitable foaming agent. These days, the use of foamed concrete has been recognized in the construction industry as wall blocks, wall panels and also material floor and roof screeds. Hence, the applications of this material should be maximized as it is multi-functional. As we know, the use of screws on the wall or ceiling is common in a building. The objective of this research is to examine and determine the pullout strength of various properties and types of screws in lightweight foamed concrete with various densities that may depict the best result of the pullout strength on foamed concrete. To visualize the different results of pullout strength, screws with and without wall plug will be used as well. The pullout strength will be tested using the Universal Testing Machine where it shall measure the ultimate load of the screws attached to the foamed concrete may resist.

Experiments on the indirect heating of low density aerogels for applications in heavy ion stopping in plasma

International Nuclear Information System (INIS)

Rosmej, O.N.; Blazevic, A.; Suslov, N.; Kunin, A.; Pinegin, A.; Schaefer, D.; Nisius, Th.; Zhao, Y.; Rinecker, T.; Wiechula, J.

2010-01-01

Complete text of publication follows. The unique combination of a Petawatt High-Energy Laser System for Ion beam eXperiments - 'Phelix' (Nd:glass, 1053 nm, 300-500 J, 1-15 ns) and intense heavy ion beams of the UNILAC accelerator at GSI-Darmstadt allow creating and probing of hot plasma with a density of some percentage of solid-state density. The experimental program aims at the investigation of fundamental features of heavy ion stopping in ionized matter in view of promising applications for the Heavy Ion Fusion and astrophysics. For combined experiments on the interaction of heavy ion beams with ionized matter (GSI) a high density plasma target with homogeneous in time (∼ 5 ns) and space (∼ 1 mm) plasma parameters in required. For these purposes we are developing the combined target which consists on the Gold hohlraum (converter) and low Z foam target heated by the hohlraum radiation before probed by an ion bunch. Foam targets are rather promising due to the effective conversion of the deposited radiation energy into the internal plasma energy and slow hydrodynamic response on the heating. Direct irradiation of the Gold converter walls with a nanosecond pulse delivered by the PHELIX-laser system (GSI) leads to hohlraum radiation spectra in the photon energy range of 50-500 eV. Expected temperatures of the foam targets heated by this radiation amount to 20-30 eV at electron densities of 10 21 cm -3 . The results of the last hohlraum experiments carried out at PHELIX-laser energies of 200-250 J will be presented. In experiments the hohlraum radiation field, the conversion efficiency of the laser energy into soft X-rays, duration of the soft X-ray pulse, and parameters of the heated with X-rays foam targets have been measured. Acknowledgements. This work is supported by ISTC 2264 grant.

Ultrathin Graphite Foam: A Three-Dimensional Conductive Network for Battery Electrodes

Energy Technology Data Exchange (ETDEWEB)

Ji, HX; Zhang, LL; Pettes, MT; Li, HF; Chen, SS; Shi, L; Piner, R; Ruoff, RS

2012-05-01

We report the use of free-standing, lightweight, and highly conductive ultrathin graphite foam (UGF), loaded with lithium iron phosphate (LFP), as a cathode in a lithium ion battery. At a high charge/discharge current density of 1280 mA g(-1), the specific capacity of the LFP loaded on UGF was 70 mAh g(-1), while LFP loaded on Al foil failed. Accounting for the total mass of the electrode, the maximum specific capacity of the UGF/LFP cathode was 23% higher than that of the Al/LFP cathode and 170% higher than that of the Ni-foam/LFP cathode. Using UGF, both a higher rate capability and specific capacity can be achieved simultaneously, owing to its conductive (similar to 1.3 x 10(5) S m(-1) at room temperature) and three-dimensional lightweight (similar to 9.5 mg cm(-3)) graphitic structure. Meanwhile, UGF presents excellent electrochemical stability comparing to that of Al and Ni foils, which are generally used as conductive substrates in lithium ion batteries. Moreover, preparation of the UGF electrode was facile, cost-effective, and compatible with various electrochemically active materials.

Foam application from a closed system – a study of machine and foam parameters

NARCIS (Netherlands)

Lemmen, Jacques T.E.; Groot Wassink, Jan

1990-01-01

An attempt has been made to gain a greater insight into the interaction between foam and a moving textile substrate. The effects of changing wet pick–up, fabric velocity, liquid viscosity, foam density and mode of application on penetration have been studied. Application from a closed system makes

Numerical simulation of anisotropic polymeric foams

Directory of Open Access Journals (Sweden)

Volnei Tita

Full Text Available This paper shows in detail the modelling of anisotropic polymeric foam under compression and tension loadings, including discussions on isotropic material models and the entire procedure to calibrate the parameters involved. First, specimens of poly(vinyl chloride (PVC foam were investigated through experimental analyses in order to understand the mechanical behavior of this anisotropic material. Then, isotropic material models available in the commercial software AbaqusTM were investigated in order to verify their ability to model anisotropic foams and how the parameters involved can influence the results. Due to anisotropy, it is possible to obtain different values for the same parameter in the calibration process. The obtained set of parameters are used to calibrate the model according to the application of the structure. The models investigated showed minor and major limitations to simulate the mechanical behavior of anisotropic PVC foams under compression, tension and multi-axial loadings. Results show that the calibration process and the choice of the material model applied to the polymeric foam can provide good quantitative results and save project time. Results also indicate what kind and order of error one will get if certain choices are made throughout the modelling process. Finally, even though the developed calibration procedure is applied to specific PVC foam, it still outlines a very broad drill to analyze other anisotropic cellular materials.

Thermal Conductivity of Foam Glass

DEFF Research Database (Denmark)

Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

Due to the increased focus on energy savings and waste recycling foam glass materials have gained increased attention. The production process of foam glass is a potential low-cost recycle option for challenging waste, e.g. CRT glass and industrial waste (fly ash and slags). Foam glass is used...... as thermal insulating material in building and chemical industry. The large volume of gas (porosity 90 – 95%) is the main reason of the low thermal conductivity of the foam glass. If gases with lower thermal conductivity compared to air are entrapped in the glass melt, the derived foam glass will contain...... only closed pores and its overall thermal conductivity will be much lower than that of the foam glass with open pores. In this work we have prepared foam glass using different types of recycled glasses and different kinds of foaming agents. This enabled the formation of foam glasses having gas cells...

Experimental and numerical analysis of the drainage of aluminium foams

International Nuclear Information System (INIS)

Brunke, O; Hamann, A; Cox, S J; Odenbach, S

2005-01-01

Drainage is one of the driving forces for the temporal instability of molten metal foams. For usual aqueous foams this phenomenon is well examined and understood on both the experimental and the theoretical side. The situation is different for metallic foams. Due to their opaque nature, the observation of drainage is only possible by either measuring the density distribution of solidified samples ex situ or by x-ray or neutron radioscopy. Up to now there exists just one theoretical study describing the drainage behaviour of metallic foams incorporating the drainage equation, the temperature dependence of the viscosity and thermal transport. This paper will present results on the drainage behaviour of aluminium foams grown by a powder-metallurgical production route. For this purpose an experiment which allows the observation of drainage in cylindrical metal foam columns has been developed. Experimental density profiles after different drainage times are measured ex situ and compared to numerical results of the standard drainage equation for aqueous foams. This first comparison between the density redistribution of metallic aluminium foams and numerical solutions shows that the standard drainage equation can be used to explain the drainage behaviour of metallic foams

Drainage effect in eutectic Al-Si foam using similar alporas process

International Nuclear Information System (INIS)

Filho, M.O.; Junior, A.C.S; Ferrandini, P.L.; Nakazato, A.Z.; Assis, W.L.S.

2016-01-01

Cellular materials have particular properties. This properties are very interesting in various type of industries, as construction, automobile and shipbuilding. Two reasons why metal foams are apply in more companies are difficult process control and high production costs. Therefore, this study aims to analyze the drainage effect in four samples produced with alloy Al-Si eutectic using CaCO 3 as foaming agent, since this is low cost than TiH 2 used normally in Alporas process and this foam have well pores uniform. For these samples has been used 700°C during all process, mixing time was 180 seconds, holding time was 150 seconds and 3,5 w.t% CaCO3. Therefore, these samples were cut transversally and analyzed what were the drainage effect on the apparent density, relative density and porosity. The free zone bubbles were noticed in all the samples. (author)

Improving the Strength of ZTA Foams with Different Strategies: Immersion Infiltration and Recoating

Directory of Open Access Journals (Sweden)

Xiaodong Chen

2017-07-01

Full Text Available The combination of high strength and toughness, excellent wear resistance and moderate density makes zirconia-toughened alumina (ZTA a favorable ceramic, and the foam version of it may also exhibit excellent properties. Here, ZTA foams were prepared by the polymer sponge replication method. We developed an immersion infiltration approach with simple equipment and operations to fill the hollow struts in as-prepared ZTA foams, and also adopted a multiple recoating method (up to four cycles to strengthen them. The solid load of the slurry imposed a significant influence on the properties of the ZTA foams. Immersion infiltration gave ZTA foams an improvement of 1.5 MPa in compressive strength to 2.6 MPa at 87% porosity, only resulting in a moderate reduction of porosity (2–3%. The Weibull modulus of the infiltrated foams was in the range of 6–9. The recoating method generated an increase in compression strength to 3.3–11.4 MPa with the reduced porosity of 58–83%. The recoating cycle dependency of porosity and compression strength is nearly linear. The immersion infiltration strategy is comparable to the industrially-established recoating method and can be applied to other reticulated porous ceramics (RPCs.

Analysis of Influence of Foaming Mixture Components on Structure and Properties of Foam Glass

Science.gov (United States)

Karandashova, N. S.; Goltsman, B. M.; Yatsenko, E. A.

2017-11-01

It is recommended to use high-quality thermal insulation materials to increase the energy efficiency of buildings. One of the best thermal insulation materials is foam glass - durable, porous material that is resistant to almost any effect of substance. Glass foaming is a complex process depending on the foaming mode and the initial mixture composition. This paper discusses the influence of all components of the mixture - glass powder, foaming agent, enveloping material and water - on the foam glass structure. It was determined that glass powder is the basis of the future material. A foaming agent forms a gas phase in the process of thermal decomposition. This aforementioned gas foams the viscous glass mass. The unreacted residue thus changes a colour of the material. The enveloping agent slows the foaming agent decomposition preventing its premature burning out and, in addition, helps to accelerate the sintering of glass particles. The introduction of water reduces the viscosity of the foaming mixture making it evenly distributed and also promotes the formation of water gas that additionally foams the glass mass. The optimal composition for producing the foam glass with the density of 150 kg/m3 is defined according to the results of the research.

Transient Thermal Response of Lightweight Cementitious Composites Made with Polyurethane Foam Waste

Science.gov (United States)

Kismi, M.; Poullain, P.; Mounanga, P.

2012-07-01

The development of low-cost lightweight aggregate (LWA) mortars and concretes presents many advantages, especially in terms of lightness and thermal insulation performances of structures. Low-cost LWA mainly comes from the recovery of vegetal or plastic wastes. This article focuses on the characterization of the thermal conductivity of innovative lightweight cementitious composites made with fine particles of rigid polyurethane (PU) foam waste. Five mortars were prepared with various mass substitution rates of cement with PU-foam particles. Their thermal conductivity was measured with two transient methods: the heating-film method and the hot-disk method. The incorporation of PU-foam particles causes a reduction of up to 18 % of the mortar density, accompanied by a significant improvement of the thermal insulating performance. The effect of segregation on the thermal properties of LWA mortars due to the differences of density among the cementitious matrix, sand, and LWA has also been quantified. The application of the hot-disk method reveals a gradient of thermal conductivity along the thickness of the specimens, which could be explained by a non-uniform repartition of fine PU-foam particles and mineral aggregates within the mortars. The results show a spatial variation of the thermal conductivity of the LWA mortars, ranging from 9 % to 19 %. However, this variation remains close to or even lower than that observed on a normal weight aggregate mortar. Finally, a self-consistent approach is proposed to estimate the thermal conductivity of PU-foam cement-based composites.

Liquid foam templating - A route to tailor-made polymer foams.

Science.gov (United States)

Andrieux, Sébastien; Quell, Aggeliki; Stubenrauch, Cosima; Drenckhan, Wiebke

2018-06-01

Solid foams with pore sizes between a few micrometres and a few millimetres are heavily exploited in a wide range of established and emerging applications. While the optimisation of foam applications requires a fine control over their structural properties (pore size distribution, pore opening, foam density, …), the great complexity of most foaming processes still defies a sound scientific understanding and therefore explicit control and prediction of these parameters. We therefore need to improve our understanding of existing processes and also develop new fabrication routes which we understand and which we can exploit to tailor-make new porous materials. One of these new routes is liquid templating in general and liquid foam templating in particular, to which this review article is dedicated. While all solid foams are generated from an initially liquid(-like) state, the particular notion of liquid foam templating implies the specific condition that the liquid foam has time to find its "equilibrium structure" before it is solidified. In other words, the characteristic time scales of the liquid foam's stability and its solidification are well separated, allowing to build on the vast know-how on liquid foams established over the last 20 years. The dispersed phase of the liquid foam determines the final pore size and pore size distribution, while the continuous phase contains the precursors of the desired porous scaffold. We review here the three key challenges which need to be addressed by this approach: (1) the control of the structure of the liquid template, (2) the matching of the time scales between the stability of the liquid template and solidification, and (3) the preservation of the structure of the template throughout the process. Focusing on the field of polymer foams, this review gives an overview of recent research on the properties of liquid foam templates and summarises a key set of studies in the emerging field of liquid foam templating. It

The intact capture of hypervelocity dust particles using underdense foams

Science.gov (United States)

Maag, Carl R.; Borg, J.; Tanner, William G.; Stevenson, T. J.; Bibring, J.-P.

1994-01-01

The impact of a hypervelocity projectile (greater than 3 km/s) is a process that subjects both the impactor and the impacted material to a large transient pressure distribution. The resultant stresses cause a large degree of fragmentation, melting, vaporization, and ionization (for normal densities). The pressure regime magnitude, however, is directly related to the density relationship between the projectile and target materials. As a consequence, a high-density impactor on a low-density target will experience the lowest level of damage. Historically, there have been three different approaches toward achieving the lowest possible target density. The first employs a projectile impinging on a foil or film of moderate density, but whose thickness is much less than the particle diameter. This results in the particle experiencing a pressure transient with both a short duration and a greatly reduced destructive effect. A succession of these films, spaced to allow nondestructive energy dissipation between impacts, will reduce the impactor's kinetic energy without allowing its internal energy to rise to the point where destruction of the projectile mass will occur. An added advantage to this method is that it yields the possibility of regions within the captured particle where a minimum of thermal modification has taken place. Polymer foams have been employed as the primary method of capturing particles with minimum degradation. The manufacture of extremely low bulk density materials is usually achieved by the introduction of voids into the material base. It must be noted, however, that a foam structure only has a true bulk density of the mixture at sizes much larger than the cell size, since for impact processes this is of paramount importance. The scale at which the bulk density must still be close to that of the mixture is approximately equal to the impactor. When this density criterion is met, shock pressures during impact are minimized, which in turn maximizes the

Rigid Polyurethane Foam from Glyco lysed Polyethylene Terephthalate Dissolved in Palm-based Polyol

International Nuclear Information System (INIS)

Khairiah Badri; Lily Iliyana Mohd Dawi; Nur Ashikin Abdul Aziz

2013-01-01

An investigation on the thermal and mechanical properties of rigid polyurethane (PU) foam from polyethylene terephthalate (PET) waste (of plastic drinking bottles) was conducted. The PET waste was glyco lysed with ethylene glycol prior to blending with palm based-polyol (PKO-p). This blend was then reacted with 2, 4-methylene diphenyl diisocyanate (MDI) at a ratio of 1:1 to form the PU foam. The incorporation of the glyco lysed PET (g-PET) into the PKO-p was studied at 50, 70 and 100 % w/ w loading. PU foam prepared from 100 % w/ w g-PET (without PKO-p) resulted in PU with high glass transition temperature and mechanical strength. This water-blown foam has molded and core densities of 182 kg m -3 and 179 kg m -3 , respectively, with maximum compressive stress and modulus at 396 kPa and 1920 kPa, respectively. An initial enthalpy value of 3164.8 cal g -1 and a glass transition temperature of 65 degree Celsius were observed. (author)

Preparation and Characteristics of Porous Ceramics by a foaming Technology at Low Temperature

Science.gov (United States)

Zhang, H. Q.; Wang, S. P.; Wen, J.; Wu, N.; Xu, S. H.

2017-12-01

Recycling and converting coal gangue and red mud into porous ceramics with good performance is a feasible disposal route. In this present work, porous foam ceramics was prepared using coal gangue and red mud as main raw materials at low sintering temperature, The amount of coal gangue and red mud were up to 70 wt%. To regulate the forming and sintering performance of the product, quartz sands and clay material were added to the formula. The green body was formed by a foaming technology using aluminum powders as foaming agents at room temperature. After foamed, the specimens were dried at 60-80 °C, and then calcined at 1060°C. Effects of concentration of NaOH and amount of aluminum powders on the phase, mechanical properties and microstructure were investigated here. Such study is expected to provide a new utilization route of the coal gangue and red mud, and brings both intensive environmental and economic benefits.

Foam Microrheology

International Nuclear Information System (INIS)

KRAYNIK, ANDREW M.; LOEWENBERG, MICHAEL; REINELT, DOUGLAS A.

1999-01-01

The microrheology of liquid foams is discussed for two different regimes: static equilibrium where the capillary number Ca is zero, and the viscous regime where viscosity and surface tension are important and Ca is finite. The Surface Evolver is used to calculate the equilibrium structure of wet Kelvin foams and dry soap froths with random structure, i.e., topological disorder. The distributions of polyhedra and faces are compared with the experimental data of Matzke. Simple shearing flow of a random foam under quasistatic conditions is also described. Viscous phenomena are explored in the context of uniform expansion of 2D and 3D foams at low Reynolds number. Boundary integral methods are used to calculate the influence of Ca on the evolution of foam microstructure, which includes bubble shape and the distribution of liquid between films, Plateau borders, and (in 3D) the nodes where Plateau borders meet. The micromechanical point of view guides the development of structure-property-processing relationships for foams

Influence of Rubber Powders on Foaming Behavior and Mechanical Properties of Foamed Polypropylene Composites

Directory of Open Access Journals (Sweden)

HE Yue

2017-02-01

Full Text Available Polypropylene/rubber powders composites with different kinds of rubber powders were foamed by injection molding machine equipped with volume-adjustable cavity. The effect of dispersity of rubber powders and crystallization behavior of composites on the foaming behavior and mechanical properties was investigated. The results show that the addition of rubber powders can improve the cell structure of foamed PP with fine and uniform cell distribution. And cell density and size of PP/PP-MAH/NBR foams are 7.64×106cell/cm3 and 29.78μm respectively, which are the best among these foams. Combining cell structures with mechanical properties, notch impact strength of PP/PP-MAH/CNBR composites increases approximately by 2.2 times while tensile strength is reduced just by 26% compared with those of the pure PP. This indicates that PP/PP-MAH/CNBR composites are ideal foamed materials.

Novel syntactic foams made of ceramic hollow micro-spheres and starch: theory, structure and properties

Energy Technology Data Exchange (ETDEWEB)

Islam, M.M.; Kim, H.S. [University of Newcastle, Callaghan, NSW (Australia). Faculty of Engineering & Built Environments

2007-08-15

Novel syntactic foams for potential building material applications were developed using starch as binder and ceramic hollow micro-spheres available as waste from coal-fired power stations. Foams of four different micro-sphere size groups were manufactured with either pre- or post-mould gelatinization process. They were of ternary system including voids with a foam density range of approximately 0.33-0.44 g/cc. Compressive failure behaviour and mechanical properties of the manufactured foams were evaluated. Not much difference in failure behaviour or in mechanical properties between the two different processes (pre- and post-mould gels) was found for a given binder content. Compressive failure of all syntactic foams was of shear on plane inclined 45 degrees to compressive loading direction. Failure surfaces of most syntactic foams were characterized by debonded micro-spheres. Compressive strength and modulus of syntactic foams were found to be dependant mainly on binder content but mostly independent of micro-sphere size. Some conditions of relativity arising from properties of constituents leading to the rule of mixtures relationships for compressive strength and to understanding of compressive/transitional failure behaviour were developed. The developed relationships based on the rule of mixtures were partially verified. Some formation of starch webs on failure surfaces was discussed.

Thermodynamic study of aqueous solutions of polyelectrolytes of low and medium charge density without added salt by direct measurement of osmotic pressure

Energy Technology Data Exchange (ETDEWEB)

Nagy, Miklos, E-mail: miklosnagy@chem.elte.h [Institute of Chemistry, Department of Physical Chemistry, Laboratory for Colloid and Supermolecular Structures, L. Eoetvoes University, P.O. Box 32 H-1518 Budapest 112 (Hungary)

2010-03-15

A special block osmometer has been constructed and applied to a systematic study of poly (vinyl alcohol and vinyl sulphate ester) (PVS) sodium salts in dilute and moderately concentrated salt free aqueous solutions. In order to avoid surely ionic contamination all parts of the equipment that can contact with the polyelectrolyte solutions were made of different kinds of plastics and glass. The pressure range spans from (50 to 1.3 . 10{sup 5}) Pa. The measuring system was found to be appropriate for determination of the molar mass of water soluble polymers, too. Above a certain analytical density of dissociable groups (ADDG) an ion size dependent transition was observed on the reduced osmotic pressure vs. concentration curves. The analysis of the osmotic pressure data has clearly revealed that the dependence of the degree of dissociation on ADDG calculated at zero polyelectrolyte concentration contradicts to 'ion condensation' theory. With increasing polyelectrolyte concentration the degree of dissociation decreased rather steeply but at very low concentrations sharp maximums appeared due either to the change in conformation of these charged macromolecules, or formation of dynamic clusters induced by salting out of neutral parts of the macromolecules by the ionized groups. The applicability of the scaling concept as well as the many possible ways of characterization of non-ideality of polyelectrolyte solutions will be discussed in detail.

Investigation of compression behavior of PE/EVA foam injection molded parts

Science.gov (United States)

Spina, Roberto

2017-10-01

The main objective of the presented work is to evaluate the compression behavior of a polymeric foam blend by using a robust framework for the testing sequence of foaming injection molded parts, with the aim of establishing a standard testing cycle for the evaluation of new matrix material. The research purpose is to assess parameters influencing compression behavior and give useful suggestions for the implementation of a finite element analysis. The polymeric blend consisted of a mixture of low density polyethylenes (LDPEs), a high-density polyethylene (HDPE), an ethylene-vinyl acetate (EVA) and an azodicarbonamide (ADC). The thermal, rheological and compression properties of the blend are fully described, as well as the injection molding process for two specimen types.

Study of two-phase foam flow

Energy Technology Data Exchange (ETDEWEB)

Gurbanov, R S; Guliev, B B; Mekhtiev, K G; Kerimov, R G

1970-01-01

The objectives of this study were to determine characteristics of aqueous foam flow through porous media and to estimate the depth of foam penetration into a formation. Foam was generated by mixing air and 1% solution of surfactant PO-1. Foam density was maintained at 0.14 g/cc in all experiments. The foam was passed through sand columns (800 mm long x 30 mm diam) of permeabilities 26, 39, 80, 111, and 133 darcys. Flow rates were measured at various pressure drops and the relationship between system parameters was expressed analytically and graphically. From the data, distance of foam penetration into a formation as a function of pressure drop and permeability was calculated. The data indicate that under most conditions, foam will penetrate the formation to a negligible distance. This study indicates that when foam is used to remove sand from a well, a negligible loss of foam to the formation occurs.

Multiscale mass-spring models of carbon nanotube foams

NARCIS (Netherlands)

Fraternali, F.; Blesgen, T.; Amendola, A.; Daraio, C.

This article is concerned with the mechanical properties of dense, vertically aligned CNT foams subject to one-dimensional compressive loading. We develop a discrete model directly inspired by the micromechanical response reported experimentally for CNT foams, where infinitesimal portions of the

Uniform Foam Crush Testing for Multi-Mission Earth Entry Vehicle Impact Attenuation

Science.gov (United States)

Patterson, Byron W.; Glaab, Louis J.

2012-01-01

Multi-Mission Earth Entry Vehicles (MMEEVs) are blunt-body vehicles designed with the purpose of transporting payloads from outer space to the surface of the Earth. To achieve high-reliability and minimum weight, MMEEVs avoid use of limited-reliability systems, such as parachutes and retro-rockets, instead using built-in impact attenuators to absorb energy remaining at impact to meet landing loads requirements. The Multi-Mission Systems Analysis for Planetary Entry (M-SAPE) parametric design tool is used to facilitate the design of MMEEVs and develop the trade space. Testing was conducted to characterize the material properties of several candidate impact foam attenuators to enhance M-SAPE analysis. In the current effort, four different Rohacell foams are tested at three different, uniform, strain rates (approximately 0.17, approximately 100, approximately 13,600%/s). The primary data analysis method uses a global data smoothing technique in the frequency domain to remove noise and system natural frequencies. The results from the data indicate that the filter and smoothing technique are successful in identifying the foam crush event and removing aberrations. The effect of strain rate increases with increasing foam density. The 71-WF-HT foam may support Mars Sample Return requirements. Several recommendations to improve the drop tower test technique are identified.

Scaling up the Fabrication of Mechanically-Robust Carbon Nanofiber Foams

Directory of Open Access Journals (Sweden)

William Curtin

2016-02-01

Full Text Available This work aimed to identify and address the main challenges associated with fabricating large samples of carbon foams composed of interwoven networks of carbon nanofibers. Solutions to two difficulties related with the process of fabricating carbon foams, maximum foam size and catalyst cost, were developed. First, a simple physical method was invented to scale-up the constrained formation of fibrous nanostructures process (CoFFiN to fabricate relatively large foams. Specifically, a gas deflector system capable of maintaining conditions supportive of carbon nanofiber foam growth throughout a relatively large mold was developed. ANSYS CFX models were used to simulate the gas flow paths with and without deflectors; the data generated proved to be a very useful tool for the deflector design. Second, a simple method for selectively leaching the Pd catalyst material trapped in the foam during growth was successfully tested. Multiple techniques, including scanning electron microscopy, surface area measurements, and mechanical testing, were employed to characterize the foams generated in this study. All results confirmed that the larger foam samples preserve the basic characteristics: their interwoven nanofiber microstructure forms a low-density tridimensional solid with viscoelastic behavior. Fiber growth mechanisms are also discussed. Larger samples of mechanically-robust carbon nanofiber foams will enable the use of these materials as strain sensors, shock absorbers, selective absorbents for environmental remediation and electrodes for energy storage devices, among other applications.

Areal thermal loading recommendations for nuclear waste repositories in salt

International Nuclear Information System (INIS)

Russell, J.E.

1979-06-01

This document gives a wider understanding of the history of the recommended thermal loadings in salt for both high-level waste (HLW) from fresh UO 2 -fueled, light-water reactors (LWR) with no recycle and spent unreprocessed fuel (SURF) from LWRs. Aspects of the current recommendations that need further study are identified. Finally, an interim set of design thermal-loading recommendations are given that have a common rationale of satisfying performance limits within our current state of knowledge. These recommendations are made on a generic rather than a site-specific basis. 11 figures, 5 tables

Thermal-gradient migration of brine inclusions in salt crystals

International Nuclear Information System (INIS)

Yagnik, S.K.

1982-09-01

It has been proposed that high-level nuclear waste be disposed in a geologic repository. Natural-salt deposits, which are being considered for this purpose, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive-decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms which is undesirable. In this work, thermal gradient migration of both all-liquid and gas-liquid inclusions was experimentally studied in synthetic single crystals of NaCl and KCl using a hot-stage attachment to an optical microscope which was capable of imposing temperature gradients and axial compressive loads on the crystals. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is non-linear.At high axial loads, however, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, three different gas phases (helium, air and argon) were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large angle grain boundaries was observed. 35 figures, 3 tables

Thermal gradient migration of brine inclusions in salt crystals

International Nuclear Information System (INIS)

Yagnik, S.K.

1982-01-01

Natural salt deposits, which are being considered for high-level nuclear wastes repositories, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine (the all-liquid inclusions) migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms which is undesirable. In the present work, thermal gradient migration of both all-liquid and gas-liquid inclusions was experimentally studied in synthetic single crystals of NaCl and KCl using a hot-stage attachment to an optical microscope which was capable of imposing temperature gradients and axial compressive loads on the crystals. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is nonlinear. At high axial loads, however, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, three different gas phases (helium, air and argon) were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large angle grain boudaries was observed

Preparation of Autoclaved Foamed Concrete Block from Fly Ash and Carbide Slag

Directory of Open Access Journals (Sweden)

Tan Xing

2018-01-01

Full Text Available To achieve the comprehensive utilization of solid waste and reduce costs, fly ash, carbide slag, and low-clinker cement were used to produce lightweight foamed concrete block. Granulated blast-furnace slag (GBFS was used as composition correction material in the block. The effects of curing temperature and dosage of low-clinker cement on the performance of foamed concrete block were investigated. The optimal material proportioning is obtained: fly ash 58.5%, carbide slag 20%, GBFS 10%, gypsum 1.5% and low-clinker cement 10%. The proper curing regime is “temperature rising 4h-180°C constant temperature 4h-natural cooling”. The results indicate that the compressive strength of the block reaches 3.55 MPa while the density is 616.9 kg/m3. The performance of the product meets JC/T 1062-2007 (China professional standard of foamed concrete block.

Engineering hierarchical ultrathin CuCo2O4 nanosheets array on Ni foam by rapid electrodeposition method toward high-performance binder-free supercapacitors

Science.gov (United States)

Abbasi, Laleh; Arvand, Majid

2018-07-01

In the present work, we engineer hierarchical ultrathin CuCo2O4 nanosheets arrays on Ni foam through a facile, controllable and low-cost electrodeposition method by controlling deposition time and adjusting precursor's type, as a binder-free electrode for high performance supercapacitors. The effects of deposition time and types of precursors on the morphology of the as-prepared electrodes were investigated by X-ray diffraction, energy dispersive X-ray analysis, field-emission scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. As a results, the CuCo2O4 electrode prepared by nitrate salts at the deposition time of 10 min, includes the most uniform and ultrathin nanosheet arrays and exhibits the highest capacitance performance, such as ultrahigh specific capacitance of 1330 F g-1 at 2 A g-1 with 70% capacitance retention (938 F g-1) at ultrahigh current density of 60 A g-1, excellent cycling stability of 93.6% capacitance retention after 5000CD cycles and the maximum energy density of 29.55 Wh kg-1 at the power density of 0.4 kW kg-1. These superior electrochemical performances have been attributed to its unique structures with direct connected ultrathin nanosheets on the surface of Ni foam and abundant pores provide large electroactive sites for electrochemical reactions, as well as facile electron, ion transport and high electrical conductivity.

Experimental Study for Structural Behaviour of Precast Lightweight Panel (PLP) Under Flexural Load

Science.gov (United States)

Goh, W. I.; Mohamad, N.; Tay, Y. L.; Rahim, N. H. A.; Jhatial, A. A.; Samad, A. A. A.; Abdullah, R.

2017-06-01

Precast lightweight concrete slab is first fabricated in workshop or industrial before construction and then transported to site and installed by skilled labour. It can reduce construction time by minimizing user delay and time for cast-in-situ to increase workability and efficiency. is environmental friendly and helps in resource reduction. Although the foamed concrete has low compressive strength compared to normal weight concrete but it has excellent thermal insulation and sound absorption. It is environmental friendly and helps in resource reduction. To determine the material properties of foamed concrete, nine cubes and six cylindrical specimens were fabricated and the results were recorded. In this study, structural behaviour of precast lightweight panel (PLP) with dry density of 1800 kg/m3 was tested under flexural load. The results were recorded and analysed in terms of ultimate load, crack pattern, load-deflection profiles and strain distribution. Linear Voltage Displacement Transducers (LVDT) and strain gauges were used to determine the deflection and strain distribution of PLP. The theoretical and experimental ultimate load of PLP was analysed and recorded to be 70 and 62 kN respectively, having a difference of 12.9%. Based on the results, it can be observed that PLP can resist the adequate loading. Thus, it can be used in precast industry for construction purposes.

Laser Smoothing and Imprint Reduction with a Foam Layer in the Multikilojoule Regime

International Nuclear Information System (INIS)

Depierreux, S.; Michel, D. T.; Riazuelo, G.; Loiseau, P.; Casanova, M.; Wrobel, R.; Alozy, E.; Soullie, G.; Reverdin, C.; Villette, B.; Labaune, C.; Riconda, C.; Stenz, C.; Nicolaie, P.; Weber, S.; Tikhonchuk, V. T.; Grech, M.; Borisenko, N. G.; Nazarov, W.; Hueller, S.

2009-01-01

This Letter presents first experimental results of the laser imprint reduction in fusion scale plasmas using a low-density foam layer. The experiments were conducted on the LIL facility at the energy level of 12 kJ with millimeter-size plasmas, reproducing the conditions of the initial interaction phase in the direct-drive scheme. The results include the generation of a supersonic ionization wave in the foam and the reduction of the initial laser fluctuations after propagation through 500 μm of foam with limited levels of stimulated Brillouin and Raman scattering. The smoothing mechanisms are analyzed and explained.

Histomorphometric, biochemical and ultrastructural changes in the aorta of salt-loaded stroke-prone spontaneously hypertensive rats fed a Japanese-style diet.

Science.gov (United States)

Baccarani Contri, M; Taparelli, F; Miselli, M; Bacchelli, B; Biagini, G

2003-02-01

It is demonstrated that dietary habits play a role in cardiovascular diseases. In stroke-prone spontaneously hypertensive rats (SHRsp), concomitant salt loading and a Japanese-style diet greatly accelerate hypertension and the appearance of cerebrovascular lesions by directly damaging arterial vessels. A number of studies have characterised medium and small vessel lesions in SHRsp, but little attention has been paid to the changes in the wall structure of large arteries induced by exposure to a salt-enriched diet. The aim of this study was to investigate the effects of a Japanese-style diet and salt loading on the thoracic aorta. Two-month-old SHRsp were kept on a Japanese-style diet with 1% sodium chloride solution replacing tap water. Two months later, they were sacrificed and compared with age-matched or two-month-old control SHRsp kept on a standard diet and tap water in terms of the histomorphometry, ultrastructure and biochemical composition of the thoracic aorta. The vessel was consistently thicker in the four-month-old SHRsp (+20%, p vs two-month-old rats) regardless of diet. The salt-loaded SHRsp showed a significant reduction in elastic fibre density (-20%, p vs two-month-old rats) and an increase in the other matrix components (%), whereas the four-month-old controls showed preserved elastic fibres and a significant increase in the other matrix components (+65%, p vs two-month-old rats). There was a considerable increase in the amounts of 4-OH-proline (+147%), 5-OH-lysine (+174%) and desmosines (+360%) in the four-month-old controls vs their two-month-old counterparts (p two months of treatment.

Safety analysis report for radwaste foam transport cask

International Nuclear Information System (INIS)

Ku, J. H.; Lee, J. C.; Bang, K. S.; Seo, K. S.; Lee, D. W.; Kim, J. H.; Park, S. W.; Lee, J. W.; Kim, K. H.

1999-08-01

For the tests and examinations of radwaste foam which generated in domestic nuclear power plants a radioactive material transport cask is needed to transport the radwaste foam from the power plants to KAERI. This cask should be easy to handle in the facilities and safe to maintain the shielding safety of operators. According to the regulations, it should be verified that this cask maintains the thermal and structural integrities under prescribed load conditions by the regulations. The basic structural functions and the integrities of the cask under required load conditions were evaluated. Therefore, it was verified that the cask is suitable to transport radwaste foam from nuclear power plants to KAERI. (author). 11 refs., 10 tabs., 25 figs

Calculation of density and permeability of compacted crushed salt within an engineered shaft sealing system

International Nuclear Information System (INIS)

Loken, M.; Statham, W.

1997-01-01

Crushed salt from the host Salado Formation is proposed as a sealing material in one component of a multicomponent seal system design for the shafts of the Waste Isolation Pilot Plant (WIPP), a mined geological repository for storage and disposal of transuranic radioactive wastes located near Carlsbad, New Mexico. The crushed salt will be compacted and placed at a density approaching 90% of the intact density of the host Salado salt. Creep closure of the shaft will further compact the crushed salt over time, thereby reducing the crushed-salt permeability from the initial state and creating an effective long-term seal. A structural model and a fluid flow model have been developed to provide an estimate of crushed-salt reconsolidation rate as a function of depth, time, and pore pressure. Model results are obtained in terms of crushed-salt permeability as a function of time and depth within the salt column. Model results indicate that average salt column permeability will be reduced to 3.3 x 10 -20 m 2 in about 100 years, which provides for an acceptable long-term seal component

Three-Dimensional Bi-Continuous Nanoporous Gold/Nickel Foam Supported MnO2 for High Performance Supercapacitors.

Science.gov (United States)

Zhao, Jie; Zou, Xilai; Sun, Peng; Cui, Guofeng

2017-12-19

A three-dimensional bi-continuous nanoporous gold (NPG)/nickel foam is developed though the electrodeposition of a gold-tin alloy on Ni foam and subsequent chemical dealloying of tin. The newly-designed 3D metal structure is used to anchor MnO 2 nanosheets for high-performance supercapacitors. The formed ternary composite electrodes exhibit significantly-enhanced capacitance performance, rate capability, and excellent cycling stability. A specific capacitance of 442 Fg -1 is achieved at a scan rate of 5 mV s -1 and a relatively high mass loading of 865 μg cm -2 . After 2500 cycles, only a 1% decay is found at a scan rate of 50 mV s -1 . A high power density of 3513 W kg -1 and an energy density of 25.73 Wh kg -1 are realized for potential energy storage devices. The results demonstrate that the NPG/nickel foam hybrid structure significantly improves the dispersibility of MnO 2 and makes it promising for practical energy storage applications.

Preparation and characterization of new biologically active polyurethane foams.

Science.gov (United States)

Savelyev, Yuri; Veselov, Vitali; Markovskaya, Ludmila; Savelyeva, Olga; Akhranovich, Elena; Galatenko, Natalya; Robota, Ludmila; Travinskaya, Tamara

2014-12-01

Biologically active polyurethane foams are the fast-developed alternative to many applications of biomedical materials. Due to the polyurethane structure features and foam technology it is possible to incorporate into their structure the biologically active compounds of target purpose via structural-chemical modification of macromolecule. A series of new biologically active polyurethane foams (PUFs) was synthesized with polyethers (MM 2500-5000), polyesters MM (500-2200), 2,4(2,6) toluene diisocyanate, water as a foaming agent, catalysts, foam stabilizers and functional compounds. Different functional compounds: 1,4-di-N-oxy-2,3-bis-(oxymethyl)-quinoxaline (DOMQ), partial sodium salt of poly(acrylic acid) and 2,6-dimethyl-N,N-diethyl aminoacetatanilide hydrochloride were incorporated into the polymer structure/composition due to the chemical and/or physical bonding. Structural peculiarities of PUFs were studied by FTIR spectroscopy and X-ray scattering. Self-adhesion properties of PUFs were estimated by measuring of tensile strength at break of adhesive junction. The optical microscopy method was performed for the PUF morphology studies. Toxicological estimation of the PUFs was carried out in vitro and in vivo. The antibacterial action towards the Gram-positive and Gram-negative bacteria (Escherichia coli ATC 25922, E. coli ATC 2150, Klebsiella pneumoniae 6447, Staphylococcus aureus 180, Pseudomonas aeruginosa 8180, Proteus mirabilis F 403, P. mirabilis 6054, and Proteus vulgaris 8718) was studied by the disc method on the solid nutrient. Physic-chemical properties of the PUFs (density, tensile strength and elongation at break, water absorption and vapor permeability) showed that all studied PUFs are within the operational requirements for such materials and represent fine-cellular foams. Spectral studies confirmed the incorporation of DOMQ into the PUF's macrochain. PUFs are characterized by microheterogeneous structure. They are antibacterially active, non

Polymer foam comprising a polymer and nanoparticles, and nanoparticles for the manufacture of such foam.

NARCIS (Netherlands)

Vancso, Gyula J.; Duvigneau, Joost; Nederkoorn, P.H.J.; Wassing, T.

2014-01-01

A polymer foam is produced comprising a polymer and nanoparticles having a maximum dimensionof 750 nm, which foam has cells with an average cell size of at most 1 µm and a cell density of at least 1012 cells/ml, wherein polymeric grafts have been attached to the nanoparticles. The nanoparticles may

High performance supercapacitors based on three-dimensional ultralight flexible manganese oxide nanosheets/carbon foam composites

Science.gov (United States)

He, Shuijian; Chen, Wei

2014-09-01

The syntheses and capacitance performances of ultralight and flexible MnO2/carbon foam (MnO2/CF) hybrids are systematically studied. Flexible carbon foam with a low mass density of 6.2 mg cm-3 and high porosity of 99.66% is simply obtained by carbonization of commercially available and low-cost melamine resin foam. With the high porous carbon foam as framework, ultrathin MnO2 nanosheets are grown through in situ redox reaction between KMnO4 and carbon foam. The three-dimensional (3D) MnO2/CF networks exhibit highly ordered hierarchical pore structure. Attributed to the good flexibility and ultralight weight, the MnO2/CF nanomaterials can be directly fabricated into supercapacitor electrodes without any binder and conductive agents. Moreover, the pseudocapacitance of the MnO2 nanosheets is enhanced by the fast ion diffusion in the three-dimensional porous architecture and by the conductive carbon foam skeleton as well as good contact of carbon/oxide interfaces. Supercapacitor based on the MnO2/CF composite with 3.4% weight percent of MnO2 shows a high specific capacitance of 1270.5 F g-1 (92.7% of the theoretical specific capacitance of MnO2) and high energy density of 86.2 Wh kg-1. The excellent capacitance performance of the present 3D ultralight and flexible nanomaterials make them promising candidates as electrode materials for supercapacitors.

An approach for characterising cellular polymeric foam structures using computed tomography

Science.gov (United States)

Chen, Youming; Das, Raj; Battley, Mark

2018-02-01

Global properties of foams depend on foam base materials and microstructures. Characterisation of foam microstructures is important for developing numerical foam models. In this study, the microstructures of four polymeric structural foams were imaged using a micro-CT scanner. Image processing and analysis methods were proposed to quantify the relative density, cell wall thickness and cell size of these foams from the captured CT images. Overall, the cells in these foams are fairly isotropic, and cell walls are rather straight. The measured average relative densities are in good agreement with the actual values. Relative density, cell size and cell wall thickness in these foams are found to vary along the thickness of foam panel direction. Cell walls in two of these foams are found to be filled with secondary pores. In addition, it is found that the average cell wall thickness measured from 2D images is around 1.4 times of that measured from 3D images, and the average cell size measured from 3D images is 1.16 times of that measured from 2D images. The distributions of cell wall thickness and cell size measured from 2D images exhibit lager dispersion in comparison to those measured from 3D images.

Influence of salting and drying, and gamma irradiation on the quality and shelf life of salted and dried Silver belly (Leiognathus spp.)

International Nuclear Information System (INIS)

Uikey, Mahendra

2015-01-01

In India about 17% of the total fishes caught are being used for salting and drying. On the global basis, 74% of the marine landings are processed by curing. Fresh Silver belly (Leognathus spp.) were procured from the fish landing centre and washed with potable water. Salting was done using food grade salt in the ratio of 1:3 (Fish to salt) in perforated steel pans by keeping the salt and fish in layer by layer fashion for 24 hrs. Drying of salted fishes was done in solar biomass hybrid drier, the final moisture content in the dried fish was 20.03%. The quality of both fresh, salted and dried fishes were analysed for chemical (Protein, fat, moisture, ash, TVB-N, TMA-N, TBARS, FFA, PV, pH) and microbial quality (TPC, halophilic count). Batches of salted and dried silver bellies were packed in high density polyethylene bags aseptically and exposed to low dose gamma irradiation (1 and 3 kGy), the non-irradiated samples were kept as control and stored at room temperature. The irradiated and control samples were analysed periodically (upto 90 days) for chemical and microbial quality. The results showed that the combined effect of salting and drying, and low dose gamma irradiation had a significant effect on microbial load (p< 0.05). The chemical parameters such as TMA-N, TVB-N and TBARS values for irradiated samples were significantly lower than the non-irradiated samples (p<0.05). The results revealed that the combination of salting and drying, and low dose gamma irradiation resulted in a significant reduction of microbial growth and chemical parameters were within the limit up to 90 days at room temperature. (author)

In situ growth of NiCo2S4 nanotube arrays on Ni foam for supercapacitors: Maximizing utilization efficiency at high mass loading to achieve ultrahigh areal pseudocapacitance

Science.gov (United States)

Chen, Haichao; Jiang, Jianjun; Zhang, Li; Xia, Dandan; Zhao, Yuandong; Guo, Danqing; Qi, Tong; Wan, Houzhao

2014-05-01

Self-standing NiCo2S4 nanotube arrays have been in situ grown on Ni foam by the anion-exchange reaction and directly used as the electrode for supercapacitors. The NiCo2S4 nanotube in the arrays effectively reduces the inactive material and increases the electroactive surface area because of the ultrathin wall, which is quite competent to achieve high utilization efficiency at high electroactive materials mass loading. The NiCo2S4 nanotube arrays hybrid electrode exhibits an ultrahigh specific capacitance of 14.39 F cm-2 at 5 mA cm-2 with excellent rate performance (67.7% retention for current increases 30 times) and cycling stability (92% retention after 5000 cycles) at a high mass loading of 6 mg cm-2. High areal capacitance (4.68 F cm-2 at 10 mA cm-2), high energy density (31.5 Wh kg-1 at 156.6 W kg-1) and high power density (2348.5 W kg-1 at 16.6 Wh kg-1) can be achieved by assembling asymmetric supercapacitor with reduced graphene oxide at a total active material mass loading as high as 49.5 mg. This work demonstrates that NiCo2S4 nanotube arrays structure is a superior electroactive material for high-performance supercapacitors even at a mass loading of potential application-specific scale.

Effect of porosity on physical properties of lightweight cement composite with foamed glass aggregate

Directory of Open Access Journals (Sweden)

Kurpińska Marzena

2017-01-01

Full Text Available This paper reports on a study of physical properties of lightweight cement composite. We investigate the possibility of replacing traditional aggregate with Granulated Ash Aggregate (GAA and above all with Granulated Expanded Glass Aggregate (GEGA. For this purpose, 15 specimens of different percentage share of each aggregate in total aggregate volume were tested: 0%, 25%, 50%, 75% or 100% of foam glass aggregate (GEGA partially replaced by ash aggregate (GAA content in the cement composite. The water-cement ratio was constant and equal to w/c=0.5. Three grain sizes were analyzed: 2mm, 4mm (both GEGA and 8mm (GAA. Numerical simulations of concrete specimen behavior under static loading were conducted with the implementation of elastic plastic model of each component. The study shows a significant impact of grain type and size on physical properties of lightweight concrete. Due to lower density of foamed glass aggregate, specimens shows various apparent density and porosity, which affect concrete properties. Compressive strength of concrete decreases with the increase in foam glass aggregate content; however specimens show different workability and in consequence porosity of lightweight concrete.

Novel wireless health monitor with acupuncture bio-potentials obtained by using a replaceable salt-water-wetted foam-rubber cushions on RFID-tag.

Science.gov (United States)

Lin, Jium-Ming; Lu, Hung-Han; Lin, Cheng-Hung

2014-01-01

This paper proposes a bio-potential measurement apparatus including a wireless device for transmitting acupuncture bio-potential information to a remote control station for health conditions analysis and monitor. The key technology of this system is to make replaceable foam-rubber cushions, double-side conducting tapes, chip and antenna on the radio frequency identification (RFID) tag. The foam-rubber cushions can be wetted with salt-water and contact with the acupuncture points to reduce contact resistance. Besides, the double-side conducting tapes are applied to fix foam-rubber cushions. Thus, one can peel the used cushions or tapes away and supply new ones quickly. Since the tag is a flexible plastic substrate, it is easy to deploy on the skin. Besides, the amplifier made by CMOS technology on RFID chip could amplify the signals to improve S/N ratio and impedance matching. Thus, cloud server can wirelessly monitor the health conditions. An example shows that the proposed system can be used as a wireless health condition monitor, the numerical method and the criteria are given to analyze eleven bio-potentials for the important acupunctures of eleven meridians on a person's hands and legs. Then a professional doctor can know the performance of an individual and the cross-linking effects of the organs.

Study of thermal-gradient-induced migration of brine inclusions in salt. Final report

International Nuclear Information System (INIS)

Olander, D.R.

1984-08-01

Natural salt deposits, which are being considered for high-level waste disposal, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine (the all-liquid inclusions) migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms, which is undesirable. Therefore it is important to consider the migration of brine inclusions in salt under imposed temperature gradients to properly evaluate the performance of a future salt repository for nuclear wastes. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is nonlinear. At high axial loads, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, helium, air and argon were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large-ange grain boundaries was observed

Study of thermal-gradient-induced migration of brine inclusions in salt. Final report

Energy Technology Data Exchange (ETDEWEB)

Olander, D.R.

1984-08-01

Natural salt deposits, which are being considered for high-level waste disposal, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine (the all-liquid inclusions) migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms, which is undesirable. Therefore it is important to consider the migration of brine inclusions in salt under imposed temperature gradients to properly evaluate the performance of a future salt repository for nuclear wastes. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is nonlinear. At high axial loads, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, helium, air and argon were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large-ange grain boundaries was observed.

Strain-rate dependence for Ni/Al hybrid foams

Directory of Open Access Journals (Sweden)

Jung Anne

2015-01-01

Full Text Available Shock absorption often needs stiff but lightweight materials that exhibit a large kinetic energy absorption capability. Open-cell metal foams are artificial structures, which due to their plateau stress, including a strong hysteresis, can in principle absorb large amounts of energy. However, their plateau stress is too low for many applications. In this study, we use highly novel and promising Ni/Al hybrid foams which consist of standard, open-cell aluminium foams, where nanocrystalline nickel is deposited by electrodeposition as coating on the strut surface. The mechanical behaviour of cellular materials, including their behaviour under higher strain-rates, is governed by their microstructure due to the properties of the strut material, pore/strut geometry and mass distribution over the struts. Micro-inertia effects are strongly related to the microstructure. For a conclusive model, the exact real microstructure is needed. In this study a micro-focus computer tomography (μCT system has been used for the analysis of the microstructure of the foam samples and for the development of a microstructural Finite Element (micro-FE mesh. The microstructural FE models have been used to model the mechanical behaviour of the Ni/Al hybrid foams under dynamic loading conditions. The simulations are validated by quasi-static compression tests and dynamic split Hopkinson pressure bar tests.

A case for closed-loop recycling of post-consumer PET for automotive foams.

Science.gov (United States)

Bedell, Matthew; Brown, Matthew; Kiziltas, Alper; Mielewski, Deborah; Mukerjee, Shakti; Tabor, Rick

2018-01-01

Striving to utilize sustainable material sources, polyester polyols made via glycolysis and esterification of recycled polyethylene terephthalate (rPET) scrap were used to synthesize flexible polyurethane (PU) foams typically found in automotive interior applications. The objective of this endeavor was to ascertain if a closed-loop model could be established with the discarded PET feedstock. In five separate formulations, up to 50% of the total polyol content (traditionally derived from petroleum-based feedstock) was replaced with the afore-mentioned sustainable recycled polyols. These foams underwent mechanical, thermal, morphological, and physical characterization testing to determine feasibility for use in an automotive interior. Young's modulus, tensile stress at maximum load, tear resistance, and compression modulus all increased by combined averages of 121%, 67%, 32%, and 150% over the control petroleum-based formulation, respectively, in foams possessing 50% rPET polyol content. Thermal stability also increased with sustainable polyol content; thermogravimetric analysis showed that 50% mass loss temperature increased by an average of 20 °C in foams containing 30% recycled polyol. Properties of density and SAG factor remained within 5% of the control petroleum-based reference foams. After comparing these findings to traditional polyols, a compelling argument can be made for the use of post-consumer automotive and industrial feedstocks in developing high-performing interior automotive PU foams. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of a low-glycemic load vs low-fat diet in obese young adults: a randomized trial.

Science.gov (United States)

Ebbeling, Cara B; Leidig, Michael M; Feldman, Henry A; Lovesky, Margaret M; Ludwig, David S

2007-05-16

The results of clinical trials involving diet in the treatment of obesity have been inconsistent, possibly due to inherent physiological differences among study participants. To determine whether insulin secretion affects weight loss with 2 popular diets. Randomized trial of obese young adults (aged 18-35 years; n = 73) conducted from September 2004 to December 2006 in Boston, Mass, and consisting of a 6-month intensive intervention period and a 12-month follow-up period. Serum insulin concentration at 30 minutes after a 75-g dose of oral glucose was determined at baseline as a measure of insulin secretion. Outcomes were assessed at 6, 12, and 18 months. Missing data were imputed conservatively. A low-glycemic load (40% carbohydrate and 35% fat) vs low-fat (55% carbohydrate and 20% fat) diet. Body weight, body fat percentage determined by dual-energy x-ray absorptiometry, and cardiovascular disease risk factors. Change in body weight and body fat percentage did not differ between the diet groups overall. However, insulin concentration at 30 minutes after a dose of oral glucose was an effect modifier (group x time x insulin concentration at 30 minutes: P = .02 for body weight and P = .01 for body fat percentage). For those with insulin concentration at 30 minutes above the median (57.5 microIU/mL; n = 28), the low-glycemic load diet produced a greater decrease in weight (-5.8 vs -1.2 kg; P = .004) and body fat percentage (-2.6% vs -0.9%; P = .03) than the low-fat diet at 18 months. There were no significant differences in these end points between diet groups for those with insulin concentration at 30 minutes below the median level (n = 28). Insulin concentration at 30 minutes after a dose of oral glucose was not a significant effect modifier for cardiovascular disease risk factors. In the full cohort, plasma high-density lipoprotein cholesterol and triglyceride concentrations improved more on the low-glycemic load diet, whereas low-density lipoprotein cholesterol

Green waste cooking oil-based rigid polyurethane foam

Science.gov (United States)

Enderus, N. F.; Tahir, S. M.

2017-11-01

Polyurethane is a versatile polymer traditionally prepared using petroleum-based raw material. Petroleum, however, is a non-renewable material and polyurethane produced was found to be non-biodegradable. In quest for a more environmentally friendly alternative, wastecooking oil, a highly abundant domestic waste with easily derivatized structure, is a viable candidate to replace petroleum. In this study,an investigation to determine physical and chemical properties of rigid polyurethane (PU) foam from waste cooking oil (WCO) was carried out. WCO was first adsorbed by using coconut husk activated carbon adsorbent prior to be used for polyol synthesis. The purified WCO was then used to synthesize polyol via transesterification reaction to yield alcohol groups in the WCO chains structure. Finally, the WCO-based polyol was used to prepare rigid PU foam. The optimum formulation for PU formation was found to be 90 polyol: 60 glycerol: 54 water: 40 diethanolamine: 23 diisocyanate. The rigid PU foam has density of 208.4 kg/m3 with maximum compressive strength and capability to receive load at 0.03 MPa and 0.09 kN, respectively. WCO-based PU can potentially be used to replace petroleum-based PU as house construction materials such as insulation panels.

Thermo-mechanical modelling of salt caverns due to fluctuating loading conditions.

Science.gov (United States)

Böttcher, N.

2015-12-01

This work summarizes the development and application of a numerical model for the thermo-mechanical behaviour of salt caverns during cyclic gas storage. Artificial salt caverns are used for short term energy storage, such as power-to-gas or compressed air energy storage. Those applications are characterized by highly fluctuating operation pressures due to the unsteady power levels of power plants based on renewable energy. Compression and expansion of the storage gases during loading and unloading stages lead to rapidly changing temperatures in the host rock of the caverns. This affects the material behaviour of the host rock within a zone that extends several meters into the rock mass adjacent to the cavern wall, and induces thermo-mechanical stresses and alters the creep response.The proposed model features the thermodynamic behaviour of the storage medium, conductive heat transport in the host rock, as well as temperature dependent material properties of rock salt using different thermo-viscoplastic material models. The utilized constitutive models are well known and state-of-the-art in various salt mechanics applications. The model has been implemented into the open-source software platform OpenGeoSys. Thermal and mechanical processes are solved using a finite element approach, coupled via a staggered coupling scheme. The simulation results allow the conclusion, that the cavern convergence rate (and thus the efficiency of the cavern) is highly influenced by the loading cycle frequency and the resulting gas temperatures. The model therefore allows to analyse the influence of operation modes on the cavern host rock or on neighbouring facilities.

Polyethoxylated carboxylic surfactant for ion foam flotation: fundamental study from solution to foam

International Nuclear Information System (INIS)

Micheau, Cyril

2013-01-01

Ion foam flotation allows to concentrate ions in a foam phase formed by a soap. For classical systems, the strong interaction between ions and surfactant generally leads to the formation of precipitates and of froth. When the froth collapses, the solid residue thus recovered requires a recycling or conversion. In order to remedy this, the present work uses as collector a polyethoxylated carboxylic surfactant, AKYPO RO 90 VG, which forms soluble ion/surfactant complexes, even with multi-charge ions. This work presents a detailed study of the fundamental mechanisms that govern the extraction of ions by foaming. In the first part, surface activity and acid/base properties of the surfactant in solution are determined by combining numerous independent techniques which are pH-metric dosage, tensiometry and small angle scattering. The evolution of these properties in the presence of different nitrate salts (Nd, Eu, Ca, Sr, Cu, Li, Na, Cs) coupled with electrophoretic measurements give a first approach to selectivity. Finally, all of these data combined with a study of the formation of surfactant/ion complexes allow us to determine the speciation of Nd/AKYPO system as a function of pH. In the second part, the analysis of the foam by conductivity and neutron scattering provides information on the wetness and foam film thickness, parameters governing foam stability. The pH and the nature of the added ions, their number of charge and also their chemical nature thus appear to be major parameters that governed wetness and foam film thickness. The last part is devoted to the understanding of the ion extraction/separation experiments by flotation based on all previous results. It is shown that the flotation of neodymium is strongly related to its speciation, which could lead to its re-extraction or its flotation in precipitated form. It is shown that, neodymium induces a phenomenon of mono-charge ion depletion in the foam. This ionic specificity allows to consider the studied

H1259 Container Foams: Performance Data on Aged Materials

International Nuclear Information System (INIS)

Linda Domeier

2002-01-01

Samples of the three cushioning foams used in the H1259 weapon storage container were obtained in 1997, 1998, 2000 and 2001 and tested for density, compression set and compressive strength using the same procedures specified for acceptance testing. Foams from six containers, all about 30 years old and located at Pantex, were evaluated. The bottom cushioning foam is a General Plastics polyurethane foam and the two side pads are rebonded polyurethane foams. All the tests were carried out at room temperature. When compared to the original acceptance requirements the foams were generally in-spec for density and compressive strength at 10% strain and were generally out-of-spec for compression set and compressive strength at 50% strain. Significant variability was noted in the performance of each foam sample and even more in the container-to-container foam performance. The container-to-container variability remains the major unknown in predicting the long-term suitability of these containers for continued use. The performance of the critical bottom cushion foams was generally more uniform and closer to the specified performance than that of the rebonded foams. It was judged that all the foams were adequate for continued use as storage container foams (not shipping) under controlled conditions to mitigate temperature extremes or high impact. This archived information is important in evaluations of the continued suitability for weapon storage use of the H1259 containers and other containers using the same foam cushions

Foaming in manure based digesters

DEFF Research Database (Denmark)

Kougias, Panagiotis; Boe, Kanokwan; Angelidaki, Irini

2012-01-01

Anaerobic digestion foaming is one of the major problems that occasionally occurred in the Danish full-scale biogas plants, affecting negatively the overall digestion process. The foam is typically formatted in the main biogas reactor or in the pre-storage tank and the entrapped solids in the foam...... cause severe operational problems, such as blockage of mixing devices, and collapse of pumps. Furthermore, the foaming problem is linked with economic consequences for biogas plants, due to income losses derived from the reduced biogas production, extra labour work and additional maintenance costs...... was increased by the addition of glucose in the feeding substrate. During the 2nd and 4th period the organic loading rate was maintained constant, but instead of glucose, higher concentration of Na-oleate or gelatine was added in the feeding substrate. The results obtained from the above experiment showed...

Sands subjected to repetitive vertical loading under zero lateral strain: accumulation models, terminal densities, and settlement

KAUST Repository

Chong, Song Hun; Santamarina, Carlos

2016-01-01

). Repetitive vertical loading tests under zero lateral strain conditions are conducted using three different sands packed at initially low and high densities. Test results show that plastic strain accumulation for all sands and density conditions can

Quasi-static characterisation and impact testing of auxetic foam for sports safety applications

International Nuclear Information System (INIS)

Duncan, Olly; Alderson, Andrew; Foster, Leon; Senior, Terry; Allen, Tom

2016-01-01

This study compared low strain rate material properties and impact force attenuation of auxetic foam and the conventional open-cell polyurethane counterpart. This furthers our knowledge with regards to how best to apply these highly conformable and breathable auxetic foams to protective sports equipment. Cubes of auxetic foam measuring 150 × 150 × 150 mm were fabricated using a thermo–mechanical conversion process. Quasi-static compression confirmed the converted foam to be auxetic, prior to being sliced into 20 mm thick cuboid samples for further testing. Density, Poisson’s ratio and the stress–strain curve were all found to be dependent on the position of each cuboid from within the cube. Impact tests with a hemispherical drop hammer were performed for energies up to 6 J, on foams covered with a polypropylene sheet between 1 and 2 mm thick. Auxetic samples reduced peak force by ∼10 times in comparison to the conventional foam. This work has shown further potential for auxetic foam to be applied to protective equipment, while identifying that improved fabrication methods are required. (paper)

Preparation and characterization of PMMA graded microporous foams via one-step supercritical carbon dioxide foaming

International Nuclear Information System (INIS)

Yuan Huan; Li Junguo; Xiong Yuanlu; Luo Guoqiang; Shen Qiang; Zhang Lianmeng

2013-01-01

Supercritical carbon dioxide (ScCO 2 ) foaming which is inexpensive and environmental friendly has been widely used to prepare polymer-based microporous materials. In this paper, PMMA graded microporous materials were foamed by PMMA matrix after an unstable saturation process which was done under supercritical condition of 28MPa and 50 °C. The scanning electron microscopy (SEM) was utilized to observe the morphology of the graded foam. A gas adsorption model was proposed to predict the graded gas concentration in the different region of the polymer matrix. The SEM results showed that the solid and foam region of the graded foam can be connected without laminated layers. With the increasing thickness position of the graded microporous foam, the cell size increased from 3.4 to 27.5 μm, while the cell density decreased from 1.04 × 10 9 to 1.96 × 10 7 cells/cm 3 . It also found that the gradient microporous structure of the foam came from graded gas concentration which was obtained in the initial saturation process.

Use of open-cell resilient polyurethane foam loaded with crown ether for the preconcentration of uranium from aqueous solutions

International Nuclear Information System (INIS)

Abou-Mesalam, M.M.; El-Naggar, I.M.; Abdel-Hai, M.S.; El-Shahawi, M.S.

2003-01-01

The preconcentration of uranium from aqueous solutions on open-cell resilient polyurethane foams (PUF) impregnated with crown ether as an organic extractant in different conditions was investigated. The data showed that 50 minutes is a sufficient time to attain equilibrium with a maximum extraction percentage for uranium ion on polyurethane foams loaded with crown ether. Also the extraction percentage of uranium is increased markedly with increasing the pH values up to pH ∼ 6 and displayed the lowest extraction at 8 > pH > 6. The different isotherms of uranium sorption have shown that the sorption followed a Freundlich isotherm. Column studies have been carried out in order to extend these studies to the plant scale. From the data of column sorption and breakthrough curves, the height equivalent of theoretical plates (HETP), and breakthrough capacity which affect the efficiency of the column have been calculated and found to be 1.03 mm/plate, 64 ± 5 and 58.3 mg uranium/gram polyurethane foam impregnated with crown ether, respectively. (author)

Automated Production of High Rep Rate Foam Targets

Science.gov (United States)

Hall, F.; Spindloe, C.; Haddock, D.; Tolley, M.; Nazarov, W.

2016-04-01

Manufacturing low density targets in the numbers needed for high rep rate experiments is highly challenging. This report summarises advances from manual production to semiautomated and the improvements that follow both in terms of production time and target uniformity. The production process is described and shown to be improved by the integration of an xyz robot with dispensing capabilities. Results are obtained from manual and semiautomated production runs and compared. The variance in the foam thickness is reduced significantly which should decrease experimental variation due to target parameters and could allow for whole batches to be characterised by the measurement of a few samples. The work applies to both foil backed and free standing foam targets.

Foaming of CRT panel glass powder with Na2CO3

DEFF Research Database (Denmark)

Petersen, Rasmus Rosenlund; König, Jakob; Smedskjær, Morten Mattrup

melt, while Na2O becomes incorporated into the glass structure. We have quantified the melt expansion through density measurements and the Na2O incorporation is indicated by the decrease of the glass transition temperature (Tg) of the final foam glass. The glass foaming quality depends on the foaming......Recycling of cathode ray tube (CRT) glass remains a challenging task. The CRT glass consists of four glass types fused together: Funnel-, neck-, frit- and panel glass. The three former glasses contain toxic lead oxide, and therefore have a low recycling potential. The latter on the other hand...... is lead-free, but since barium and strontium oxide are present, panel glass is incompatible with most common recycling methods. However, foam glass production is a promising approach for the recycling of panel glass waste, since the process parameters can be changed according to the glass waste...

Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

Energy Technology Data Exchange (ETDEWEB)

Karim, Ahmad Fikri Abdul, E-mail: a.fikri-89@yahoo.com; Ariff, Zulkifli Mohamad [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Ismail, Hanafi [Cluster for Polymer Composites (CPC), Science and Engineering Research Centre, Engineering Campus, Universiti Sains Malaysia,14300 Nibong Tebal, Pulau Pinang (Malaysia)

2015-07-22

This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM)

Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

International Nuclear Information System (INIS)

Karim, Ahmad Fikri Abdul; Ariff, Zulkifli Mohamad; Ismail, Hanafi

2015-01-01

This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM)

New Whole-House Solutions Case Study: The Impact of Thermostat Placement in Low-Load Homes in Sunny Climates

Energy Technology Data Exchange (ETDEWEB)

None

2016-02-23

The Building America team IBACOS has found that low-load homes (zero energy ready homes) have differing room-to-room load densities and highly variable load densities throughout the day and year because of solar gains and internal gains.

Density Fluctuation in Aqueous Solutions and Molecular Origin of Salting-Out Effect for CO2

International Nuclear Information System (INIS)

Ho, Tuan Anh; Ilgen, Anastasia

2017-01-01

Using molecular dynamics simulation, we studied the density fluctuations and cavity formation probabilities in aqueous solutions and their effect on the hydration of CO 2 . With increasing salt concentration, we report an increased probability of observing a larger than the average number of species in the probe volume. Our energetic analyses indicate that the van der Waals and electrostatic interactions between CO 2 and aqueous solutions become more favorable with increasing salt concentration, favoring the solubility of CO 2 (salting in). However, due to the decreasing number of cavities forming when salt concentration is increased, the solubility of CO 2 decreases. The formation of cavities was found to be the primary control on the dissolution of gas, and is responsible for the observed CO 2 salting-out effect. Finally, our results provide the fundamental understanding of the density fluctuation in aqueous solutions and the molecular origin of the salting-out effect for real gas.

Separation of uranium by extraction with foamed plastics

International Nuclear Information System (INIS)

Korkisch, J.

1983-07-01

Polyurethane foams are frequently used for the extraction and separation of inorganic and organic species. The attraction of the materials lies in their favourable hydrodynamic properties obviating the need for the forced-flow conditions associated with conventional chromatographic-type column packing of small particles. The research work described has been directed to providing information on the extraction and separation of uranium (and thorium) by an open-cell polyurethane foam from media containing nitrates and from hydrochloric acid systems. The influence of many different experimental parameters (concentrations, acidity, impregnation of the foam with organic extractants) on the extraction was investigated. Based on the results of these investigations two methods were developed to separate uranium from nitric acid solution and from hydrochloric acid solution, respectively. The first uses calcium or aluminium nitrate salting and foam impregnated with Aliquat 336, the second ascorbic acid addition and TOPO-impregnated foam. The methods separate uranium and thorium from each other and from most other elements and can be used analytically or in the purification of uranium from impure plant products such as yellow cake

Experimental Study on Fatigue Performance of Foamed Lightweight Soil

Science.gov (United States)

Qiu, Youqiang; Yang, Ping; Li, Yongliang; Zhang, Liujun

2017-12-01

In order to study fatigue performance of foamed lightweight soil and forecast its fatigue life in the supporting project, on the base of preliminary tests, beam fatigue tests on foamed lightweight soil is conducted by using UTM-100 test system. Based on Weibull distribution and lognormal distribution, using the mathematical statistics method, fatigue equations of foamed lightweight soil are obtained. At the same time, according to the traffic load on real road surface of the supporting project, fatigue life of formed lightweight soil is analyzed and compared with the cumulative equivalent axle loads during the design period of the pavement. The results show that even the fatigue life of foamed lightweight soil has discrete property, the linear relationship between logarithmic fatigue life and stress ratio still performs well. Especially, the fatigue life of Weibull distribution is more close to that derived from the lognormal distribution, in the instance of 50% guarantee ratio. In addition, the results demonstrated that foamed lightweight soil as subgrade filler has good anti-fatigue performance, which can be further adopted by other projects in the similar research domain.

Durability of Low Platinum Fuel Cells Operating at High Power Density

Energy Technology Data Exchange (ETDEWEB)

Polevaya, Olga [Nuvera Fuel Cells Inc.; Blanchet, Scott [Nuvera Fuel Cells Inc.; Ahluwalia, Rajesh [Argonne National Lab; Borup, Rod [Los-Alamos National Lab; Mukundan, Rangachary [Los-Alamos National Lab

2014-03-19

Understanding and improving the durability of cost-competitive fuel cell stacks is imperative to successful deployment of the technology. Stacks will need to operate well beyond today’s state-of-the-art rated power density with very low platinum loading in order to achieve the cost targets set forth by DOE ($15/kW) and ultimately be competitive with incumbent technologies. An accelerated cost-reduction path presented by Nuvera focused on substantially increasing power density to address non-PGM material costs as well as platinum. The study developed a practical understanding of the degradation mechanisms impacting durability of fuel cells with low platinum loading (≤0.2mg/cm2) operating at high power density (≥1.0W/cm2) and worked out approaches for improving the durability of low-loaded, high-power stack designs. Of specific interest is the impact of combining low platinum loading with high power density operation, as this offers the best chance of achieving long-term cost targets. A design-of-experiments approach was utilized to reveal and quantify the sensitivity of durability-critical material properties to high current density at two levels of platinum loading (the more conventional 0.45 mgPt.cm–1 and the much lower 0.2 mgPt.cm–2) across several cell architectures. We studied the relevance of selected component accelerated stress tests (AST) to fuel cell operation in power producing mode. New stress tests (NST) were designed to investigate the sensitivity to the addition of electrical current on the ASTs, along with combined humidity and load cycles and, eventually, relate to the combined city/highway drive cycle. Changes in the cathode electrochemical surface area (ECSA) and average oxygen partial pressure on the catalyst layer with aging under AST and NST protocols were compared based on the number of completed cycles. Studies showed elevated sensitivity of Pt growth to the potential limits and the initial particle size distribution. The ECSA loss

Features of metabolic reactions to various water-salt loads in female rats

Directory of Open Access Journals (Sweden)

Anatoliy I Gozhenko

2018-04-01

Full Text Available Background. In the previous article we reported that screening registered parameters of water-salt, nitrous and lipid metabolism as well as the neuroendocrine-immune complex found 42 among them who in rats subjected to various water-salt loads, significantly different from that of intact rats, but on average the same group of animals that received liquids with different mineralization and chemical composition. The purpose of this article is to find out the features of the reactions of the parameters of metabolism. Materials and methods. Experiment was performed on 58 healthy female Wistar rats 240-290 g divided into 6 groups. Animals of the first group remained intact, using tap water from drinking ad libitum. Instead, the other rats received the same tap water as well as waters Sophiya, Naftussya, Gertsa and its artificial salt analogue through the probe at a dose of 1,5 mL/100 g of body mass for 6 days. The day after the completion of the drinking course in all rats the parameters of water-salt, nitrous and lipid metabolism were registered. Results. Found that 16 metabolic parameters the maximum deviates from the level of intact rats under the influence of the salt analogue of Gertsa water, a smaller, but tangible effect is made by the Gertsa native water, even less effective waters Sofiya and Naftussya, instead of ordinary water is almost ineffective in relation to these metabolic parameters. The other 19 parameters deviates to a maximum extent from the reference level after the use of water Naftussya, fresh water is less effective, whereas quasi-isotonic liquids are practically inactive for these parameters. The remaining 13 parameters in animals that use normal water, deviates from intact control to the same extent as in the previous pattern, which, apparently, is also due to the stressful effects of the load course. Both Naftussya and Gertsa water and its salt analogue prevent the stress deviations of these parameters. Instead, by

Calculating salt loads to Great Salt Lake and the associated uncertainties for water year 2013; updating a 48 year old standard

Science.gov (United States)

Shope, Christopher L.; Angeroth, Cory E.

2015-01-01

Effective management of surface waters requires a robust understanding of spatiotemporal constituent loadings from upstream sources and the uncertainty associated with these estimates. We compared the total dissolved solids loading into the Great Salt Lake (GSL) for water year 2013 with estimates of previously sampled periods in the early 1960s.We also provide updated results on GSL loading, quantitatively bounded by sampling uncertainties, which are useful for current and future management efforts. Our statistical loading results were more accurate than those from simple regression models. Our results indicate that TDS loading to the GSL in water year 2013 was 14.6 million metric tons with uncertainty ranging from 2.8 to 46.3 million metric tons, which varies greatly from previous regression estimates for water year 1964 of 2.7 million metric tons. Results also indicate that locations with increased sampling frequency are correlated with decreasing confidence intervals. Because time is incorporated into the LOADEST models, discrepancies are largely expected to be a function of temporally lagged salt storage delivery to the GSL associated with terrestrial and in-stream processes. By incorporating temporally variable estimates and statistically derived uncertainty of these estimates,we have provided quantifiable variability in the annual estimates of dissolved solids loading into the GSL. Further, our results support the need for increased monitoring of dissolved solids loading into saline lakes like the GSL by demonstrating the uncertainty associated with different levels of sampling frequency.

Potential of Hollow Glass Microsphere as Cement Replacement for Lightweight Foam Concrete on Thermal Insulation Performance

Directory of Open Access Journals (Sweden)

Shahidan Shahiron

2017-01-01

Full Text Available Global warming can be defined as a gradual increase in the overall temperature of the earth’s atmosphere. A lot of research work has been carried out to reduce that heat inside the residence such as the used of low density products which can reduce the self-weight, foundation size and construction costs. Foamed concrete it possesses high flow ability, low self-weight, minimal consumption of aggregate, controlled low strength and excellent thermal insulation properties. This study investigate the characteristics of lightweight foamed concrete where Portland cement (OPC was replaced by hollow glass microsphere (HGMs at 0%, 3%, 6%, 9% by weight. The density of wet concrete is 1000 kg/m3 were tested with a ratio of 0.55 for all water binder mixture. Lightweight foamed concrete hollow glass microsphere (HGMs produced were cured by air curing and water curing in tank for 7, 14 and 28 days. A total of 52 concrete cubes of size 100mm × 100mm × 100mm and 215mm × 102.5mm × 65mm were produced. Furthermore, Scanning Electron Microscope (SEM and X-ray fluorescence (XRF were carried out to study the chemical composition and physical properties of crystalline materials in hollow glass microspheres. The experiments involved in this study are compression strength, water absorption test, density and thermal insulation test. The results show that the compressive strength of foamed concrete has reached the highest in 3% of hollow glass microsphere with less water absorption and less of thermal insulation. As a conclusion, the quantity of hollow glass microsphere plays an important role in determining the strength and water absorption and also thermal insulation in foamed concrete and 3% hollow glass microspheres as a replacement for Portland cement (OPC showed an optimum value in this study as it presents a significant effect than other percentage.

Polyurethane foam loaded with SDS for the adsorption of cationic dyes from aqueous medium: Multivariate optimization of the loading process.

Science.gov (United States)

Robaina, Nicolle F; Soriano, Silvio; Cassella, Ricardo J

2009-08-15

This paper reports the development of a new procedure for the adsorption of four cationic dyes (Rhodamine B, Methylene Blue, Crystal Violet and Malachite Green) from aqueous medium employing polyurethane foam (PUF) loaded with sodium dodecylsulfate (SDS) as solid phase. PUF loading process was based on the stirring of 200mg PUF cylinders with acidic solutions containing SDS. The conditions for loading were optimized by response surface methodology (RSM) using a Doehlert design with three variables that were SDS and HCl concentrations and stirring time. Results obtained in the optimization process showed that the stirring time is not a relevant parameter in the PUF loading, evidencing that the transport of SDS from solution to PUF surface is fast. On the other hand, both SDS and HCl concentrations were important parameters causing significant variation in the efficiency of the resulting solid phase for the removal of dyes from solution. At optimized conditions, SDS and HCl concentrations were 4.0 x 10(-4) and 0.90 mol L(-1), respectively. The influence of stirring time was evaluated by univariate methodology. A 20 min stirring time was established in order to make the PUF loading process fast and robust without losing efficiency. The procedure was tested for the removal of the four cationic dyes from aqueous solutions and removal efficiencies always better than 90% were achieved for the two concentrations tested (2.0 x 10(-5) and 1.0 x 10(-4)mol L(-1)).

Elasticity Modulus and Flexural Strength Assessment of Foam Concrete Layer of Poroflow

Science.gov (United States)

Hajek, Matej; Decky, Martin; Drusa, Marian; Orininová, Lucia; Scherfel, Walter

2016-10-01

Nowadays, it is necessary to develop new building materials, which are in accordance to the principles of the following provisions of the Roads Act: The design of road is a subject that follows national technical standards, technical regulations and objectively established results of research and development for road infrastructure. Foam concrete, as a type of lightweight concrete, offers advantages such as low bulk density, thermal insulation and disadvantages that will be reduced by future development. The contribution focuses on identifying the major material characteristics of foam concrete named Poroflow 17-5, in order to replace cement-bound granular mixtures. The experimental measurements performed on test specimens were the subject of diploma thesis in 2015 and continuously of the dissertation thesis and grant research project. At the beginning of the contribution, an overview of the current use of foam concrete abroad is elaborated. Moreover, it aims to determine the flexural strength of test specimens Poroflow 17-5 in combination with various basis weights of the underlying geotextile. Another part of the article is devoted to back-calculation of indicative design modulus of Poroflow based layers based on the results of static plate load tests provided at in situ experimental stand of Faculty of Civil Engineering, University of Žilina (FCE Uniza). Testing stand has been created in order to solve problems related to research of road and railway structures. Concern to building construction presents a physical homomorphic model that is identical with the corresponding theory in all structural features. Based on the achieved material characteristics, the tensile strength in bending of previously used road construction materials was compared with innovative alternative of foam concrete and the suitability for the base layers of pavement roads was determined.

Design and fabrication of highly open nickel cobalt sulfide nanosheets on Ni foam for asymmetric supercapacitors with high energy density and long cycle-life

Science.gov (United States)

Zha, Daosong; Fu, Yongsheng; Zhang, Lili; Zhu, Junwu; Wang, Xin

2018-02-01

Nickel cobalt sulfides (NiCo-S) are promising electrode materials for high-performance supercapacitors but normally show poor rate capability and unsatisfactory long-term endurance. To overcome these disadvantages, a properly constructed electrode architecture with abundant electron transport channels, excellent electronic conductivity and robust structural stability is required. Herein, considering that in situ transformation can mostly retain the specific structural advantages of the precursors, a two-step strategy is purposefully developed to construct a binder-free electrode composed of interconnected NiCo-S nanosheets on Ni foam (NiCo-S/NF), in which NiCo-S/NF is synthesized via the in situ sulfuration of networked acetate anion-intercalated nickel cobalt layered double hydroxide nanosheets loaded on Ni foam (A-NiCo-LDH/NF). Noticeably, the optimized Ni1Co1-S/NF exhibits an ultrahigh specific capacitance of 2553.9 F g-1 at 0.5 A g-1, excellent rate capability (1898.1 F g-1 at 50 A g-1) and superior cycling stability (nearly 90% capacitance retention after 10,000 cycles). Furthermore, the assembled asymmetric supercapacitor based on Ni1Co1-S/NF demonstrates a high energy density of 58.1 Wh kg-1 at a power density of 796 W kg-1 and impressive long-term durability even after a repeated charge/discharge process as long as 70,000 cycles (∼92% capacitance retention). The attractive properties endow the Ni1Co1-S/NF electrode with significant potential for high-performance energy storage devices.

Fractal-like thickness and topography of the salt layer in a pillows province of the southern North Sea

Science.gov (United States)

Hernandez Maya, K.; Mitchell, N. C.; Huuse, M.

2017-12-01

Salt topography and thickness variations are important for testing theories of how halokinetic deformation proceeds. The ability to predict thickness variations of salt at small scale is also important for reservoir evaluations, as breach of the salt layer can lead to loss of petroleum fluids and can be difficult to evaluate from seismic reflection data. Relevant to these issues, we here report analysis of data on salt layer topography and thickness from the southern North Sea, where the salt is organized into pillows. These data were derived by the Geological Survey of the Netherlands (TNO) from industry 3D seismic reflection data combined with a dense network of well information. Highs and lows in the topography of the upper salt interface occur spaced over a variety of lengthscales. Power spectral analysis of the interface topography reveals a simple inverse power law relationship between power spectral density and spatial wave number. The relationship suggests that the interface is a self-affine fractal with a fractal dimension of 2.85. A similar analysis of the salt layer thickness also suggests a fractal-like power law. Whereas the layer thickness power law is unsurprising as the underlying basement topography dominates the thickness and it also has a fractal-like power spectrum, the salt topography is not so easily explained as not all the basement faults are overlaid by salt pillows, instead some areas of the dataset salt thinning overlies faults. We consider instead whether a spatially varied loading of the salt layer may have caused this fractal-like geometry. Varied density and thickness of overburdening layers seem unlikely causes, as thicknesses of layers and their reflectivities do not vary sympathetically with the topography of the interface. The composition of the salt layer varies with the relative proportions of halite and denser anhydrite and other minerals. Although limited in scope and representing the mobilized salt layer, the information from

Low molecular weight salts combined with fluorinated solvents for electrolytes

Science.gov (United States)

Tikhonov, Konstantin; Yip, Ka Ki; Lin, Tzu-Yuan; Lei, Norman; Guerrero-Zavala, Guillermo; Kwong, Kristie W.

2015-11-10

Provided are electrochemical cells and electrolytes used to build such cells. An electrolyte includes at least one salt having a molecular weight less than about 250. Such salts allow forming electrolytes with higher salt concentrations and ensure high conductivity and ion transport in these electrolytes. The low molecular weight salt may have a concentration of at least about 0.5M and may be combined with one or more other salts, such as linear and cyclic imide salts and/or methide salts. The concentration of these additional salts may be less than that of the low molecular weight salt, in some embodiments, twice less. The additional salts may have a molecular weight greater than about 250. The electrolyte may also include one or more fluorinated solvents and may be capable of maintaining single phase solutions at between about -30.degree. C. to about 80.degree. C.

Prediction of the Stress-Strain Behavior of Open-Cell Aluminum Foam under Compressive Loading and the Effects of Various RVE Boundary Conditions

Science.gov (United States)

Hamidi Ghaleh Jigh, Behrang; Farsi, Mohammad Ali; Hosseini Toudeshky, Hossein

2018-04-01

The prediction of the mechanical behavior of metallic foams with realistic microstructure and the effects of various boundary conditions on the mechanical behavior is an important and challenging issue in modeling representative volume elements (RVEs). A numerical investigation is conducted to determine the effects of various boundary conditions and cell wall cross sections on the compressive mechanical properties of aluminum foam, including the stiffness, plateau stress and onset strain of densification. The open-cell AA6101-T6 aluminum foam Duocel is used in the analyses in this study. Geometrical characteristics including the cell size, foam relative density, and cross-sectional shape and thickness of the cell walls are extracted from images of the foam. Then, the obtained foam microstructure is analyzed as a 2D model. The ligaments are modeled as shear deformable beams with elastic-plastic material behavior. To prevent interpenetration of the nodes and walls inside the cells with large deformations, self-contact-type frictionless interaction is stipulated between the internal surfaces. Sensitivity analyses are performed using several boundary conditions and cells wall cross-sectional shapes. The predicted results from the finite element analyses are compared with the experimental results. Finally, the most appropriate boundary conditions, leading to more consistent results with the experimental data, are introduced.

Prediction of the Stress-Strain Behavior of Open-Cell Aluminum Foam under Compressive Loading and the Effects of Various RVE Boundary Conditions

Science.gov (United States)

Hamidi Ghaleh Jigh, Behrang; Farsi, Mohammad Ali; Hosseini Toudeshky, Hossein

2018-05-01

The prediction of the mechanical behavior of metallic foams with realistic microstructure and the effects of various boundary conditions on the mechanical behavior is an important and challenging issue in modeling representative volume elements (RVEs). A numerical investigation is conducted to determine the effects of various boundary conditions and cell wall cross sections on the compressive mechanical properties of aluminum foam, including the stiffness, plateau stress and onset strain of densification. The open-cell AA6101-T6 aluminum foam Duocel is used in the analyses in this study. Geometrical characteristics including the cell size, foam relative density, and cross-sectional shape and thickness of the cell walls are extracted from images of the foam. Then, the obtained foam microstructure is analyzed as a 2D model. The ligaments are modeled as shear deformable beams with elastic-plastic material behavior. To prevent interpenetration of the nodes and walls inside the cells with large deformations, self-contact-type frictionless interaction is stipulated between the internal surfaces. Sensitivity analyses are performed using several boundary conditions and cells wall cross-sectional shapes. The predicted results from the finite element analyses are compared with the experimental results. Finally, the most appropriate boundary conditions, leading to more consistent results with the experimental data, are introduced.

Plasticity and damage in aluminum syntactic foams deformed under dynamic and quasi-static conditions

Energy Technology Data Exchange (ETDEWEB)

Balch, Dorian K. [Northwestern University, Evanston, IL (United States); O' Dwyer, John G. [Waterford Institute of Technology (Ireland); Davis, Graham R. [Queen Mary, University of London (United Kingdom); Cady, Carl M. [Los Alamos National Laboratory, Los Alamos, NM (United States); Gray, George T. [Los Alamos National Laboratory, Los Alamos, NM (United States); Dunand, David C. [Northwestern University, Evanston, IL (United States)]. E-mail: dunand@northwestern.edu

2005-01-25

Syntactic foams were fabricated by liquid metal infiltration of commercially pure and 7075 aluminum into preforms of hollow ceramic microspheres. The foams exhibited peak strengths during quasi-static compression ranging from -100 to -230 MPa, while dynamic compression loading showed a 10-30% increase in peak strength magnitude, with strain rate sensitivities similar to those of aluminum-matrix composite materials. X-ray tomographic investigation of the post-compression loaded foam microstructures revealed sharp differences in deformation modes, with the unalloyed-Al foam failing initially by matrix deformation, while the alloy-matrix foams failed more abruptly through the formation of sharp crush bands oriented at about 45 deg. to the compression axis. These foams displayed pronounced energy-absorbing capabilities, suggesting their potential use in packaging applications or for impact protection; proper tailoring of matrix and microsphere strengths would result in optimized syntactic foam properties.

Primary and Reflected Compaction Waves in a Foam Rod Due to an Axial Impact by a Small Mass

Directory of Open Access Journals (Sweden)

D. Karagiozova

Full Text Available AbstractThe propagation of compaction waves in a stationary foam block subjected to an impact by a small mass is studied in order to examine the mechanism of compaction within the primary and reflected stress waves. The analysis is focused on aluminium strain rate insensitive foam that exhibits strain hardening under quasistatic compression. A theoretical approach is applied using a uniaxial model of compaction in which the compacted strains, being functions of the velocity variation, are not predefined but are obtained as a part of the solution. The present approach allows one to obtain the strain histories and strain distributions within the primary compaction wave as well as within the reflected wave, which propagates in a media with non-uniform density increasing monotonically in the direction of loading. FE simulations considering aluminium based foam Cymat with density 411.5 kg/m3 are carried out in order to verify the proposed theoretical model. A comparison between the impact velocity attenuation predicted by the present model and classical Rigid Perfectly-Plastic Locking material model for cellular materials is discussed.

High insulation foam glass material from waste cathode ray tube panel glass

DEFF Research Database (Denmark)

König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

. In general CRT consists of two types of glasses: barium/strontium containing glass (panel glass) and lead containing glass (funnel and panel glass). In this work we present the possibility to produce high performance insulation material from the recycled lead-free glass. We studied the influence of foaming...... between 750 and 850°C. We investigated the influence of milling time, particle size, foaming and oxidizing agent concentrations, temperature and time on the foaming process, foam density, foam porosity and homogeneity. Only moderate foaming was observed in carbon containing samples, while the addition...... of the oxidizing agent greatly improved the foaming quality. The results showed that the amount of oxygen available from the glass is not sufficient to combust all of the added carbon, therefore, additional oxygen was supplied via manganese reduction. In general, a minimum in the foam glass density was observed...

A complete process for the treatment of low level radioactive wastes using composite ion exchange resins based on polyurethane foam

International Nuclear Information System (INIS)

Rao, S.V.S.; Mani, A.G.S.; Lakshmi, R.; Sinha, P.K.

2007-01-01

The CFC-PU foam and HMO-PU foams have been employed for the removal of radioactive cesium and strontium respectively from actual Cat. III radioactive liquid waste received from reprocessing plant. Batch studies have been carried out in order to optimize the loading of above chemicals. The results of column and batch studies have indicated that there is a good agreement between them. After passing about 1000 bed volumes, the average DF and volume reduction factor obtained were 20 and 200 respectively. A method has been developed for the wet digestion of spent resins in alkaline KMnO 4 medium. The digested foam has been immobilized in cement matrix and the matrices were characterized with respect to compressive strength and leach resistance. (author)

Blast-Resistant Improvement of Sandwich Armor Structure with Aluminum Foam Composite

OpenAIRE

Yang, Shu; Qi, Chang

2013-01-01

Sandwich armor structures with aluminum foam can be utilized to protect a military vehicle from harmful blast load such as a landmine explosion. In this paper, a system-level dynamic finite element model is developed to simulate the blast event and to evaluate the blast-resistant performance of the sandwich armor structure. It is found that a sandwich armor structure with only aluminum foam is capable of mitigating crew injuries under a moderate blast load. However, a severe blast load causes...

Investigation of low-frequency-oscillating water flow in metal foam with 10 pores per inch

Science.gov (United States)

Bağcı, Ö.; Arbak, A.; De Paepe, M.; Dukhan, N.

2018-01-01

In this study, oscillating water flow in metal foam with open cells is investigated experimentally. The metal foam sample has a porosity of 88% and 10 pores. The water was oscillated in the test section with three frequencies between 0.116 Hz and 0.348 Hz, which are considered low for water oscillation, and three flow displacements ranging between 74.35 mm and 111.53 mm. The combinations of frequencies of displacements were studied for their impacts of dimensional and non-dimensional pressure loss quantities. To this purpose, friction factor was correlated as a function of kinetic Reynolds number. The same metal foam sample was studied by exposing it to steady-state water flow to investigate its permeability and drag coefficient in low-velocity flow regimes. The friction factor distribution for oscillating flow was found to be over that found for steady state. The outcomes of the study are important for studying heat transfer under the same flow conditions.

Intertwined nanocarbon and manganese oxide hybrid foam for high-energy supercapacitors.

Science.gov (United States)

Wang, Wei; Guo, Shirui; Bozhilov, Krassimir N; Yan, Dong; Ozkan, Mihrimah; Ozkan, Cengiz S

2013-11-11

Rapid charging and discharging supercapacitors are promising alternative energy storage systems for applications such as portable electronics and electric vehicles. Integration of pseudocapacitive metal oxides with single-structured materials has received a lot of attention recently due to their superior electrochemical performance. In order to realize high energy-density supercapacitors, a simple and scalable method is developed to fabricate a graphene/MWNT/MnO2 nanowire (GMM) hybrid nanostructured foam, via a two-step process. The 3D few-layer graphene/MWNT (GM) architecture is grown on foamed metal foils (nickel foam) via ambient pressure chemical vapor deposition. Hydrothermally synthesized α-MnO2 nanowires are conformally coated onto the GM foam by a simple bath deposition. The as-prepared hierarchical GMM foam yields a monographical graphene foam conformally covered with an intertwined, densely packed CNT/MnO2 nanowire nanocomposite network. Symmetrical electrochemical capacitors (ECs) based on GMM foam electrodes show an extended operational voltage window of 1.6 V in aqueous electrolyte. A superior energy density of 391.7 Wh kg(-1) is obtained for the supercapacitor based on the GMM foam, which is much higher than ECs based on GM foam only (39.72 Wh kg(-1) ). A high specific capacitance (1108.79 F g(-1) ) and power density (799.84 kW kg(-1) ) are also achieved. Moreover, the great capacitance retention (97.94%) after 13 000 charge-discharge cycles and high current handability demonstrate the high stability of the electrodes of the supercapacitor. These excellent performances enable the innovative 3D hierarchical GMM foam to serve as EC electrodes, resulting in energy-storage devices with high stability and power density in neutral aqueous electrolyte. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modeling of low-capillary number segmented flows in microchannels using OpenFOAM

NARCIS (Netherlands)

Hoang, D.A.; Van Steijn, V.; Portela, L.M.; Kreutzer, M.T.; Kleijn, C.R.

2012-01-01

Modeling of low-Capillary number segmented flows in microchannels is important for the design of microfluidic devices. We present numerical validations of microfluidic flow simulations using the volume-of-fluid (VOF) method as implemented in OpenFOAM. Two benchmark cases were investigated to ensure

Utilization of fly ash and ultrafine GGBS for higher strength foam concrete

Science.gov (United States)

Gowri, R.; Anand, K. B.

2018-02-01

Foam concrete is a widely accepted construction material, which is popular for diverse construction applications such as, thermal insulation in buildings, lightweight concrete blocks, ground stabilization, void filling etc. Currently, foam concrete is being used for structural applications with a density above 1800kg/m3. This study focuses on evolving mix proportions for foam concrete with a material density in the range of 1200 kg/m3 to 1600 kg/m3, so as to obtain strength ranges that will be sufficient to adopt it as a structural material. Foam concrete is made lighter by adding pre-formed foam of a particular density to the mortar mix. The foaming agent used in this study is Sodium Lauryl Sulphate and in order to densify the foam generated, Sodium hydroxide solution at a normality of one is also added. In this study efforts are made to make it a sustainable construction material by incorporating industrial waste products such as ultrafine GGBS as partial replacement of cement and fly ash for replacement of fine aggregate. The fresh state and hardened state properties of foam concrete at varying proportions of cement, sand, water and additives are evaluated. The proportion of ultrafine GGBS and fly ash in the foam concrete mix are varied aiming at higher compressive strength. Studies on air void-strength relationship of foam concrete are also included in this paper.

Geometry anisotropy and mechanical property isotropy in titanium foam fabricated by replica impregnation method

International Nuclear Information System (INIS)

Manonukul, Anchalee; Srikudvien, Pathompoom; Tange, Makiko; Puncreobutr, Chedtha

2016-01-01

Polyurethane (PU) foams have both geometry and mechanical property anisotropy. Metal foams, which are manufacturing by investment casting or melt deposition method and using PU foam as a template, also have mechanical property anisotropy. This work studied the mechanical properties in two directions of titanium foam with four different cell sizes fabricated using the replica impregnation method. The two directions are (1) the loading direction parallel to the foaming direction where the cells are elongated (EL direction) and (2) the loading direction perpendicular to the foaming direction where the cell are equiaxed (EQ direction). The results show that the compression responses for both EL and EQ directions are isotropy. Micrographs and X-ray micro-computed tomography show that the degree of geometry anisotropy is not strong enough to results in mechanical property anisotropy.

Geometry anisotropy and mechanical property isotropy in titanium foam fabricated by replica impregnation method

Energy Technology Data Exchange (ETDEWEB)

Manonukul, Anchalee, E-mail: anchalm@mtec.or.th [National Metal and Materials Technology Center (MTEC), National Science and Technology Development Agency (NSTDA), 114 Thailand Science Park, Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Srikudvien, Pathompoom [National Metal and Materials Technology Center (MTEC), National Science and Technology Development Agency (NSTDA), 114 Thailand Science Park, Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Tange, Makiko [Taisei Kogyo Thailand Co., Ltd., Room INC2d-409, Innovation Cluster 2 Building, Tower D, 141 Thailand Science Park, Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Puncreobutr, Chedtha [Department of Metallurgical Engineering, Faculty of Engineering, Chulalongkorn University, Pathumwan, Bangkok 10330 (Thailand)

2016-02-08

Polyurethane (PU) foams have both geometry and mechanical property anisotropy. Metal foams, which are manufacturing by investment casting or melt deposition method and using PU foam as a template, also have mechanical property anisotropy. This work studied the mechanical properties in two directions of titanium foam with four different cell sizes fabricated using the replica impregnation method. The two directions are (1) the loading direction parallel to the foaming direction where the cells are elongated (EL direction) and (2) the loading direction perpendicular to the foaming direction where the cell are equiaxed (EQ direction). The results show that the compression responses for both EL and EQ directions are isotropy. Micrographs and X-ray micro-computed tomography show that the degree of geometry anisotropy is not strong enough to results in mechanical property anisotropy.

Salidroside protects against foam cell formation and apoptosis, possibly via the MAPK and AKT signaling pathways.

Science.gov (United States)

Ni, Jing; Li, Yuanmin; Li, Weiming; Guo, Rong

2017-10-10

Foam cell formation and apoptosis are closely associated with atherosclerosis pathogenesis. We determined the effect of salidroside on oxidized low-density lipoprotein (ox-LDL)-induced foam cell formation and apoptosis in THP1 human acute monocytic leukemia cells and investigated the associated molecular mechanisms. THP1-derived macrophages were incubated with salidroside for 5 h and then exposed to ox-LDL for 24 h to induce foam cell formation. Cytotoxicity, lipid deposition, apoptosis, and the expression of various proteins were tested using the CCK8 kit, Oil Red O staining, flow cytometry, and western blotting, respectively. Ox-LDL treatment alone promoted macrophage-derived foam cell formation, while salidroside treatment alone inhibited it (p foam cell formation and apoptosis, partly by regulating the MAPK and Akt signaling pathways.

Microcellular foams via phase separation

International Nuclear Information System (INIS)

Young, A.T.

1985-01-01

A study of wide variety of processes for making plastic foams shows that phase separation processes for polymers from solutions offers the most viable methods for obtaining rigid plastic foams which met the physical requirements for fusion target designs. Four general phase separation methods have been shown to give polymer foams with densities less than 0.1 g/cm 3 and cell sizes of 30μm or less. These methods involve the utilization of non-solvent, chemical or thermal cooling processes to achieve a controlled phase separation wherein either two distinct phases are obtained where the polymer phase is a continuous phase or two bicontinuous phases are obtained where both the polymer and solvent are interpenetrating, continuous, labyrinthine phases. Subsequent removal of the solvent gives the final foam structure

Modification of Foamed Articles Based on Cassava Starch

International Nuclear Information System (INIS)

Ponce, P.

2006-01-01

This work reports the influence of radiation, plasticizers and poly vinyl alcohol (PVA) on the barrier properties [water vapour permeability (WVP)) and mechanical properties (tensile strength and elongation; compression resistance and flexibility) of foamed articles based on cassava starch. The starch foam was obtained by thermopressing process. Poly ethylene glycol (PEG, 300) was selected as plasticizer and water was necessary for the preparation of the foams. The foamed articles based on cassava starch were irradiated at low doses of 2 and 5 kGy, commonly used in food irradiation. The mechanical properties of starch foams are influenced by the plasticizer concentration and by irradiation dose. An increase in PEG content showed a considerable increase in elongation percentage and a decrease in the tensile strength of the foams; also increase the permeability of the foams in water. After irradiation, the barrier properties and mechanical properties of the foams were improved due to chemical reactions among polymer molecules. Irradiated starch cassava foams with poly vinyl alcohol (PVA) have good flexibility and low water permeability. WVP can be reduced by low doses of gamma radiation

Tooling Foam for Structural Composite Applications

Science.gov (United States)

DeLay, Tom; Smith, Brett H.; Ely, Kevin; MacArthur, Doug

1998-01-01

Tooling technology applications for composite structures fabrication have been expanded at MSFC's Productivity Enhancement Complex (PEC). Engineers from NASA/MSFC and Lockheed Martin Corporation have developed a tooling foam for use in composite materials processing and manufacturing that exhibits superior thermal and mechanical properties in comparison with other tooling foam materials. This tooling foam is also compatible with most preimpregnated composite resins such as epoxy, bismaleimide, phenolic and their associated cure cycles. MARCORE tooling foam has excellent processability for applications requiring either integral or removable tooling. It can also be tailored to meet the requirements for composite processing of parts with unlimited cross sectional area. A shelf life of at least six months is easily maintained when components are stored between 50F - 70F. The MARCORE tooling foam system is a two component urethane-modified polyisocyanurate, high density rigid foam with zero ozone depletion potential. This readily machineable, lightweight tooling foam is ideal for composite structures fabrication and is dimensionally stable at temperatures up to 350F and pressures of 100 psi.

Manufacturing of Cast Metal Foams with Irregular Cell Structure

Directory of Open Access Journals (Sweden)

Kroupová I.

2015-06-01

Full Text Available Metallic foams are materials of which the research is still on-going, with the broad applicability in many different areas (e.g. automotive industry, building industry, medicine, etc.. These metallic materials have specific properties, such as large rigidity at low density, high thermal conductivity, capability to absorb energy, etc. The work is focused on the preparation of these materials using conventional casting technology (infiltration method, which ensures rapid and economically feasible method for production of shaped components. In the experimental part we studied conditions of casting of metallic foams with open pores and irregular cell structure made of ferrous and nonferrous alloys by use of various types of filler material (precursors.

Creep of sandwich beams with metallic foam cores

International Nuclear Information System (INIS)

Kesler, O.; Crews, L.K.; Gibson, L.J.

2003-01-01

The steady state creep deflection rates of sandwich beams with metallic foam cores were measured and compared with analytical and numerical predictions of the creep behavior. The deflection rate depends on the geometry of the sandwich beam, the creep behavior of the foam core and the loading conditions (stress state, temperature). Although there was a considerable scatter in the creep data (both of the foams and of the sandwich beams made using them), the data for the sandwich beams were fairly well described by the analysis

Creep of sandwich beams with metallic foam cores

Energy Technology Data Exchange (ETDEWEB)

Kesler, O.; Crews, L.K.; Gibson, L.J

2003-01-20

The steady state creep deflection rates of sandwich beams with metallic foam cores were measured and compared with analytical and numerical predictions of the creep behavior. The deflection rate depends on the geometry of the sandwich beam, the creep behavior of the foam core and the loading conditions (stress state, temperature). Although there was a considerable scatter in the creep data (both of the foams and of the sandwich beams made using them), the data for the sandwich beams were fairly well described by the analysis.

Low-Salt Intake during Mating or Gestation in Rats Is Associated with Low Birth and Survival Rates of Babies

Directory of Open Access Journals (Sweden)

Ranna Chou

2014-01-01

Full Text Available We investigated the influence of maternal salt restriction during mating or gestation on birth rate and offspring growth in Dahl salt-sensitive rats (DS. DS were divided into 5 groups: DS fed a low-salt (0.3% NaCl, w/w (DS-low or high-salt (4% NaCl, w/w diet (DS-high during mating and DS-high or DS-low during gestation, and DS fed regular chow (0.75% NaCl, w/w (DS-regular throughout mating and gestation. During the unspecified periods, the rats were given regular chow. DS-low during mating delivered fewer infants than high-salt mothers (P<0.05. The birth rate on regular chow was 87%. Six out of 11 DS-low rats during pregnancy produced pups while the rats fed a high-salt diet all delivered pups (P<0.025. The pup survival rate was 67% for high-salt mothers during mating and 54% for mothers on a low-salt diet. The pup survival rate was 95% for mothers on a high-salt diet during pregnancy and 64% for mothers on a low-salt diet (P<0.0001. Seven out of 8 DS-regular rats during mating delivered 59 neonates. However, 66% of the neonates survived. A low-salt diet during mating or pregnancy lowers birth rate and the neonates from low-salt mothers during pregnancy were more likely to die than those from high-salt mothers.

Churn-annular foam flow: experiments and modelling

NARCIS (Netherlands)

Westende, J.M.C. van 't; Shoeibi Omrani, P.; Vercauteren, F.F.; Nennie, E.D.

2016-01-01

Foam assisted lift is a deliquification method in the oil and gas industry, which aims to prevent or postpone countercurrent gas-liquid flow in maturing gas wells or to assist in removing downhole accumulated liquids. The creation of foam reduces the density of the liquid that needs to be

Foaming of CRT panel glass powder using Na2CO3

DEFF Research Database (Denmark)

Petersen, Rasmus Rosenlund; König, Jakob; Smedskjær, Morten Mattrup

2014-01-01

The recycling of glass from obsolete cathode ray tubes (CRT) has hitherto only occurred to a very limited extent, but the production of foam glass used as an insulation material component has recently been proposed as a promising recycling method. CRT panel glass has high recycling potential due...... to its non-hazardous composition. Here we report on the foaming of CRT panel glass using Na2CO3 as the foaming agent. We explore how heat treatment temperature and concentration of Na2CO3 affect the density and porosity of the foam glasses, and whether Na2O is incorporated in the glass network....... The optimum foaming temperature for minimising density and maximising closed porosity is found to be between 1023 and 1123 K. The pore structure depends on the amount of added Na2CO3, viz, the pores generally become more open with increasing Na2CO3 content. A minimum density of 0·28 g/cm3 is found when 14 wt...

Detection and Characterization of Flaws in Sprayed on Foam Insulation with Pulsed Terahertz Frequency Electromagnetic Waves

Science.gov (United States)

Winfree, William P.; Madaras, Eric I.

2005-01-01

The detection and repair of flaws such as voids and delaminations in the sprayed on foam insulation of the external tank reduces the probability of foam debris during shuttle ascent. The low density of sprayed on foam insulation along with it other physical properties makes detection of flaws difficult with conventional techniques. An emerging technology that has application for quantitative evaluation of flaws in the foam is pulsed electromagnetic waves at terahertz frequencies. The short wavelengths of these terahertz pulses make them ideal for imaging flaws in the foam. This paper examines the application of terahertz pulses for flaw detection in foam characteristic of the foam insulation of the external tank. Of particular interest is the detection of voids and delaminations, encapsulated in the foam or at the interface between the foam and a metal backing. The technique is shown to be capable of imaging small voids and delaminations through as much as 20 cm of foam. Methods for reducing the temporal responses of the terahertz pulses to improve flaw detection and yield quantitative characterizations of the size and location of the flaws are discussed.

Porous materials based on foaming solutions obtained from industrial waste

Science.gov (United States)

Starostina, I. V.; Antipova, A. N.; Ovcharova, I. V.; Starostina, Yu L.

2018-03-01

This study analyzes foam concrete production efficiency. Research has shown the possibility of using a newly-designed protein-based foaming agent to produce porous materials using gypsum and cement binders. The protein foaming agent is obtained by alkaline hydrolysis of a raw mixture consisting of industrial waste in an electromagnetic field. The mixture consists of spent biomass of the Aspergillus niger fungus and dust from burning furnaces used in cement production. Varying the content of the foaming agent allows obtaining gypsum binder-based foam concretes with the density of 200-500 kg/m3 and compressive strength of 0.1-1.0 MPa, which can be used for thermal and sound insulation of building interiors. Cement binders were used to obtain structural and thermal insulation materials with the density of 300-950 kg/m3 and compressive strength of 0.9-9.0 MPa. The maximum operating temperature of cement-based foam concretes is 500°C because it provides the shrinkage of less than 2%.

Mechanical properties and impact behavior of a microcellular structural foam

Directory of Open Access Journals (Sweden)

M. Avalle

Full Text Available Structural foams are a relatively new class of materials with peculiar characteristics that make them very attractive in some energy absorption applications. They are currently used for packaging to protect goods from damage during transportation in the case of accidental impacts. Structural foams, in fact, have sufficient mechanical strength even with reduced weight: the balance between the two antagonist requirements demonstrates that these materials are profitable. Structural foams are generally made of microcellular materials, obtained by polymers where voids at the microscopic level are created. Although the processing technologies and some of the material properties, including mechanical, are well known, very little is established for what concerns dynamic impact properties, for the design of energy absorbing components made of microcellular foams. The paper reports a number of experimental results, in different loading conditions and loading speed, which will be a basis for the structural modeling.

Fluoride Rinses, Gels and Foams

DEFF Research Database (Denmark)

Twetman, Svante; Keller, Mette K

2016-01-01

AIM: The aim of this conference paper was to systematically review the quality of evidence and summarize the findings of clinical trials published after 2002 using fluoride mouth rinses, fluoride gels or foams for the prevention of dental caries. METHODS: Relevant papers were selected after...... (6 on fluoride mouth rinse, 10 on fluoride gel and 3 on fluoride foam); 6 had a low risk of bias while 2 had a moderate risk. All fluoride measures appeared to be beneficial in preventing crown caries and reversing root caries, but the quality of evidence was graded as low for fluoride mouth rinse......, moderate for fluoride gel and very low for acidulated fluoride foam. No conclusions could be drawn on the cost-effectiveness. CONCLUSIONS: This review, covering the recent decade, has further substantiated the evidence for a caries-preventive effect of fluoride mouth rinse, fluoride gel and foam...

Ablative overlays for Space Shuttle leading edge ascent heat protection

Science.gov (United States)

Strauss, E. L.

1975-01-01

Ablative overlays were evaluated via a plasma-arc simulation of the ascent pulse on the leading edge of the Space Shuttle Orbiter. Overlay concepts included corkboard, polyisocyanurate foam, low-density Teflon, epoxy, and subliming salts. Their densities ranged from 4.9 to 81 lb per cu ft, and the thicknesses varied from 0.107 to 0.330 in. Swept-leading-edge models were fabricated from 30-lb per cu ft silicone-based ablators. The overlays were bonded to maintain the surface temperature of the base ablator below 500 F during ascent. Foams provided minimum-weight overlays, and subliming salts provided minimum-thickness overlays. Teflon left the most uniform surface after ascent heating.

Continued Optimization of Low-Density Foam-Reinforced Ablatives for High-Velocity, High Heat Flux Earth Return Missions,, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — In previous work for NASA, Ultramet and ARA Ablatives Laboratory developed and demonstrated advanced foam-reinforced carbon/phenolic ablators that offer...

Investigation of gating parameter, temperature and density effects on mold filling in the lost foam casting (LFC process by direct observation method

Directory of Open Access Journals (Sweden)

A. Sharifi

2013-03-01

Full Text Available Mold filling sequence of A356 aluminum alloy was investigated with the aid of direct observation method (photography method. The results show that increase of the foam density causes decrease of the filling rate and increase of the filling time. Foam density has more pronounced effect on mold filling rate rather than pouring temperature. Gating design also affects the profile of molten metal advancement in the mold. The results show that the higher filling rate was obtained with G2 gating than with other gating system. Regarding the mold filling pattern, G3 gating system has more effective contact interface than G2 gating system and has lower filling time. Filling time in G4 gating and G1 gating system are nearly the same.

Insert Design and Manufacturing for Foam-Core Composite Sandwich Structures

Science.gov (United States)

Lares, Alan

Sandwich structures have been used in the aerospace industry for many years. The high strength to weight ratios that are possible with sandwich constructions makes them desirable for airframe applications. While sandwich structures are effective at handling distributed loads such as aerodynamic forces, they are prone to damage from concentrated loads at joints or due to impact. This is due to the relatively thin face-sheets and soft core materials typically found in sandwich structures. Carleton University's Uninhabited Aerial Vehicle (UAV) Project Team has designed and manufactured a UAV (GeoSury II Prototype) which features an all composite sandwich structure fuselage structure. The purpose of the aircraft is to conduct geomagnetic surveys. The GeoSury II Prototype serves as the test bed for many areas of research in advancing UAV technologies. Those areas of research include: low cost composite materials manufacturing, geomagnetic data acquisition, obstacle detection, autonomous operations and magnetic signature control. In this thesis work a methodology for designing and manufacturing inserts for foam-core sandwich structures was developed. The results of this research work enables a designer wishing to design a foam-core sandwich airframe structure, a means of quickly manufacturing optimized inserts for the safe introduction of discrete loads into the airframe. The previous GeoSury II Prototype insert designs (v.1 & v.2) were performance tested to establish a benchmark with which to compare future insert designs. Several designs and materials were considered for the new v.3 inserts. A plug and sleeve design was selected, due to its ability to effectively transfer the required loads to the sandwich structure. The insert material was chosen to be epoxy, reinforced with chopped carbon fibre. This material was chosen for its combination of strength, low mass and also compatibility with the face-sheet material. The v.3 insert assembly is 60% lighter than the

Effect of Cerium(IV)-Surfactant Reaction in Foam Decontamination

Energy Technology Data Exchange (ETDEWEB)

Yang, Han Beom; Jung, Chong-Hun; Yoon, In-Ho; Kim, Chorong; Choi, Wang-Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

Using foams allows the decommissioning of complex shaped facilities. The decontamination foam comprises at least one surfactant to generate the foam and one or more chemical reactants to achieve the dissolution of the contaminants at the solid surface. In order to improve the efficiency of decontamination foam, the present study attempts to find the optimum condition of chemical reagents to the foaming solution. The corrosion rate of radioactive nuclides contaminated stainless steel metal is very important factor for the foam decontamination process. The goal of this study is to develop the decontamination process for contaminated stainless steel in medium of nitric acid. Stainless steel needs a strong oxidizing agent such as Ce(IV) ion and the effects of cerium(IV). Surfactant interaction involved in foam decontamination and finally the improvement brought by formulation science. The formulation of foams loaded with strong oxidizing reagents such as Ce(IV) is an important factor. The enhanced decontamination properties of nitric acid with Ce(IV) additive on stainless steel is well known in liquid mediums. stainless steel metal is an important aspect in the foam decontamination process.

Effect of Cerium(IV)-Surfactant Reaction in Foam Decontamination

International Nuclear Information System (INIS)

Yang, Han Beom; Jung, Chong-Hun; Yoon, In-Ho; Kim, Chorong; Choi, Wang-Kyu

2015-01-01

Using foams allows the decommissioning of complex shaped facilities. The decontamination foam comprises at least one surfactant to generate the foam and one or more chemical reactants to achieve the dissolution of the contaminants at the solid surface. In order to improve the efficiency of decontamination foam, the present study attempts to find the optimum condition of chemical reagents to the foaming solution. The corrosion rate of radioactive nuclides contaminated stainless steel metal is very important factor for the foam decontamination process. The goal of this study is to develop the decontamination process for contaminated stainless steel in medium of nitric acid. Stainless steel needs a strong oxidizing agent such as Ce(IV) ion and the effects of cerium(IV). Surfactant interaction involved in foam decontamination and finally the improvement brought by formulation science. The formulation of foams loaded with strong oxidizing reagents such as Ce(IV) is an important factor. The enhanced decontamination properties of nitric acid with Ce(IV) additive on stainless steel is well known in liquid mediums. stainless steel metal is an important aspect in the foam decontamination process

Experiments, modeling and simulation of the magnetic behavior of inhomogeneously coated nickel/aluminum hybrid foams

Energy Technology Data Exchange (ETDEWEB)

Jung, A., E-mail: anne.jung@mx.uni-saarland.de [Universität des Saarlandes, Institute of Applied Mechanics, Campus A4 2, 66123 Saarbrücken (Germany); Klis, D., E-mail: d.klis@lte.uni-saarland.de [Universität des Saarlandes, Laboratory for Electromagnetic Theory, Campus C6 3, 66123 Saarbrücken (Germany); Goldschmidt, F., E-mail: f.goldschmidt@mx.uni-saarland.de [Universität des Saarlandes, Institute of Applied Mechanics, Campus A4 2, 66123 Saarbrücken (Germany)

2015-03-15

Open-cell metal foams are used as lightweight construction elements, energy absorbers or as support for catalytic coatings. Coating of open-cell metal foams is not only used for catalytic applications, but it leads also to tremendous increase in stiffness and energy absorption capacity. A non-line of sight coating technique for complex 3D structures is electrodeposition. Unfortunately, due to the 3D porosity and the related problems in mass transport limitation during the deposition, it is not possible to produce homogeneously coated foams. In the present contribution, we present a semi-non-destructive technique applicable to determine the coating thickness distribution of magnetic coatings by measuring the remanent magnetic field of coated foams. In order to have a closer look at the mass transport mechanism, a numerical model was developed to predict the field scans for different coating thickness distributions in the foams. For long deposition times the deposition reaches a steady state whereas a Helmholtz equation is sufficient to predict the coating thickness distribution. The applied current density could be identified as the main influencing parameter. Based on the developed model, it is possible to improve the electrodeposition process and hence the homogeneity in the coating thickness of coated metal foams. This leads to enhanced mechanical properties of the hybrid foams and contributes to better and resource-efficient energy absorbers and lightweight materials. - Highlights: • Production of hybrid foams by electrodeposition of nickel on open-cell metal foams. • Magnetic field scans for visualization of spatial coating thickness distribution. • Modeling of magnetic fields of inhomogeneously coated hybrid foams. • Investigation of mass transport limitation during coating by a Helmholtz equation. • Increasing coating homogeneity by use of low current densities and deposition rates.

High-Potential Metalless Nanocarbon Foam Supercapacitors Operating in Aqueous Electrolyte.

Science.gov (United States)

Liu, Chueh; Li, Changling; Ahmed, Kazi; Mutlu, Zafer; Lee, Ilkeun; Zaera, Francisco; Ozkan, Cengiz S; Ozkan, Mihrimah

2018-04-01

Light-weight graphite foam decorated with carbon nanotubes (dia. 20-50 nm) is utilized as an effective electrode without binders, conductive additives, or metallic current collectors for supercapacitors in aqueous electrolyte. Facile nitric acid treatment renders wide operating potentials, high specific capacitances and energy densities, and long lifespan over 10 000 cycles manifested as 164.5 and 111.8 F g -1 , 22.85 and 12.58 Wh kg -1 , 74.6% and 95.6% capacitance retention for 2 and 1.8 V, respectively. Overcharge protection is demonstrated by repetitive cycling between 2 and 2.5 V for 2000 cycles without catastrophic structural demolition or severe capacity fading. Graphite foam without metallic strut possessing low density (≈0.4-0.45 g cm -3 ) further reduces the total weight of the electrode. The thorough investigation of the specific capacitances and coulombic efficiencies versus potential windows and current densities provides insights into the selection of operation conditions for future practical devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Compressive Deformation Behavior of Closed-Cell Micro-Pore Magnesium Composite Foam

Directory of Open Access Journals (Sweden)

Jing Wang

2018-05-01

Full Text Available The closed-cell micro-pore magnesium composite foam with hollow ceramic microspheres (CMs was fabricated by a modified melt foaming method. The effect of CMs on the compressive deformation behavior of CM-containing magnesium composite foam was investigated. Optical microscopy and scanning electron microscopy were used for observation of the microstructure. Finite element modeling of the magnesium composite foam was established to predict localized stress, fracture of CMs, and the compressive deformation behavior of the foam. The results showed that CMs and pores directly affected the compressive deformation behavior of the magnesium composite foam by sharing a part of load applied on the foam. Meanwhile, the presence of Mg2Si phase influenced the mechanical properties of the foam by acting as the crack source during the compression process.

Foam Transport in Porous Media - A Review

Energy Technology Data Exchange (ETDEWEB)

Zhang, Z. F.; Freedman, Vicky L.; Zhong, Lirong

2009-11-11

Amendment solutions with or without surfactants have been used to remove contaminants from soil. However, it has drawbacks such that the amendment solution often mobilizes the plume, and its movement is controlled by gravity and preferential flow paths. Foam is an emulsion-like, two-phase system in which gas cells are dispersed in a liquid and separated by thin liquid films called lamellae. Potential advantages of using foams in sub-surface remediation include providing better control on the volume of fluids injected, uniformity of contact, and the ability to contain the migration of contaminant laden liquids. It is expected that foam can serve as a carrier of amendments for vadose zone remediation, e.g., at the Hanford Site. As part of the U.S. Department of Energy’s EM-20 program, a numerical simulation capability will be added to the Subsurface Transport Over Multiple Phases (STOMP) flow simulator. The primary purpose of this document is to review the modeling approaches of foam transport in porous media. However, as an aid to understanding the simulation approaches, some experiments under unsaturated conditions and the processes of foam transport are also reviewed. Foam may be formed when the surfactant concentration is above the critical micelle concentration. There are two main types of foams – the ball foam (microfoam) and the polyhedral foam. The characteristics of bulk foam are described by the properties such as foam quality, texture, stability, density, surface tension, disjoining pressure, etc. Foam has been used to flush contaminants such as metals, organics, and nonaqueous phase liquids from unsaturated soil. Ball foam, or colloidal gas aphrons, reportedly have been used for soil flushing in contaminated site remediation and was found to be more efficient than surfactant solutions on the basis of weight of contaminant removed per gram of surfactant. Experiments also indicate that the polyhedral foam can be used to enhance soil remediation. The

Applicability of Solid Solution Heat Treatments to Aluminum Foams

Directory of Open Access Journals (Sweden)

Miguel Rodríguez-Pérez

2012-12-01

Full Text Available Present research work evaluates the influence of both density and size on the treatability of Aluminum-based (6000 series foam-parts subjected to a typical solid solution heat treatment (water quenching. The results are compared with those obtained for the bulk alloy, evaluating the fulfilment of cooling requirements. Density of the foams was modeled by tomography analysis and the thermal properties calculated, based on validated density-scaled models. With this basis, cooling velocity maps during water quenching were predicted by finite element modeling (FEM in which boundary conditions were obtained by solving the inverse heat conduction problem. Simulations under such conditions have been validated experimentally. Obtained results address incomplete matrix hardening for foam-parts bigger than 70 mm in diameter with a density below 650 kg/m3. An excellent agreement has been found in between the predicted cooling maps and final measured microhardness profiles.

Pd-Pt loaded graphene aerogel on nickel foam composite as binder-free anode for a direct glucose fuel cell unit

Science.gov (United States)

Tsang, Chi Him A.; Leung, D. Y. C.

2017-09-01

Fabrication of electrocatalyst for direct glucose fuel cell (DGFC) operation involves destructive preparation methods with the use of stabilizer like binder, which may cause activity depreciation. Binder-free electrocatalytic electrode becomes a possible solution to the above problem. Binder-free bimetallic Pd-Pt loaded graphene aerogel on nickel foam plates with different Pd/Pt ratios (1:2.32, 1:1.62, and 1:0.98) are successfully fabricated through a green one-step mild reduction process producing a Pd-Pt/GO/nickel form plate (NFP) composite. Anode with the binder-free electrocatalysts exhibit a strong activity in a batch type DGFC unit under room temperature. The effects of glucose and KOH concentrations, and the Pd/Pt ratios of the electrocatalyst on the DGFC performance are also studied. Maximum power density output of 1.25 mW cm-2 is recorded with 0.5 M glucose/3 M KOH as the anodic fuel, and Pd1Pt0.98/GA/NFP as catalyst, which is the highest obtained so far among other types of electrocatalyst.

Thermal Transport in High-Strength Polymethacrylimide (PMI) Foam Insulations

Science.gov (United States)

Qiu, L.; Zheng, X. H.; Zhu, J.; Tang, D. W.; Yang, S. Y.; Hu, A. J.; Wang, L. L.; Li, S. S.

2015-11-01

Thermal transport in high-strength polymethacrylimide (PMI) foam insulations is described, with special emphasis on the density and temperature effects on the thermal transport performance. Measurements of the effective thermal conductivity are performed by a freestanding sensor-based 3ω method. A linear relationship between the density and the effective thermal conductivity is observed. Based on the analysis of the foam insulation morphological structures and the corresponding geometrical cell model, the quantitative contribution of the solid conductivity and the gas conductivity as well as the radiative conductivity to the total effective thermal conductivity as a function of the density and temperature is calculated. The agreement between the curves of the results from the developed model and experimental data indicate the model can be used for PMI foam insulating performance optimization.

Properties of Foamed Mortar Prepared with Granulated Blast-Furnace Slag

OpenAIRE

Zhao, Xiao; Lim, Siong-Kang; Tan, Cher-Siang; Li, Bo; Ling, Tung-Chai; Huang, Runqiu; Wang, Qingyuan

2015-01-01

Foamed mortar with a density of 1300 kg/m3 was prepared. In the initial laboratory trials, water-to-cement (w/c) ratios ranging from 0.54 to 0.64 were tested to determine the optimal value for foamed mortar corresponding to the highest compressive strength without compromising its fresh state properties. With the obtained optimal w/c ratio of 0.56, two types of foamed mortar were prepared, namely cement-foamed mortar (CFM) and slag-foamed mortar (SFM, 50% cement was replaced by slag weight). ...

Removal of salt from high-level waste tanks by density-driven circulation or mechanical agitation

International Nuclear Information System (INIS)

Kiser, D.L.

1981-01-01

Twenty-two high-level waste storage tanks at the Savannah River Plant are to be retired in the tank replacement/waste transfer program. The salt-removal portion of this program requires dissolution of about 19 million liters of salt cake. Steam circulation jets were originally proposed to dissolve the salt cake. However, the jets heated the waste tank to 80 to 90 0 C. This high temperature required a long cooldown period before transfer of the supernate by jet, and increased the risk of stress-corrosion cracking in these older tanks. A bench-scale investigation at the Savannah River Laboratory developed two alternatives to steam-jet circulation. One technique was density-driven circulation, which in bench tests dissolved salt at the same rate as a simulated steam circulation jet but at a lower temperature. The other technique was mechanical agitation, which dissolved the salt cake faster and required less fresh water than either density-driven circulation or the simulated steam circulation jet. Tests in an actual waste tank verified bench-scale results and demonstrated the superiority of mechanical agitation

Mass transfer measurements in foams

International Nuclear Information System (INIS)

Leblond, J.G.; Fournel, B.

2004-01-01

Full text of publication follows:This study participates to the elaboration of a method for decontamination of the inside surfaces of steel structures (pipes, tanks,...). The solution which has been chosen is to attack the surface of the structure by a dipping solution. In order to reduce the quantity of product to be recovered and treated at the end of the cleaning process, the active solution will be introduced as a foam. During its free or forced drainage the foam supplies an active liquid film along the structure surfaces. It was important to know if the transfers of the dipping liquid inside the foam and between foam and wall film are sufficient to allow a correct supplying of the active liquid at the wall and a correct dragging of the dipped products. The objective of this work is to develop a numerical model which simulates the various transfers. However such a modeling cannot be performed without a thorough knowledge of the different transfer parameters in the foam and in the film. The following study has been performed on a model foam (foaming water + air) held in a smooth vertical glass pipe and submitted to a forced drainage by the foaming water (water + surfactants). The liquid transfer involves the dispersion of the drainage liquid inside the foam and the transfer between the foam and the liquid film flowing down at the wall. The different transfers has been analyzed by NMR using a PFGSE-NMR sequence, which allows to determine the propagator, i.e., the probability density of the liquid particle displacements during a given time interval Δt, along a selected direction. This study allowed to measure, firstly, the mean liquid and the liquid dispersion in the foam along the vertical and horizontal direction, and secondly, the vertical mean velocity in the parietal liquid film. (authors)

Multifunctional Stiff Carbon Foam Derived from Bread.

Science.gov (United States)

Yuan, Ye; Ding, Yujie; Wang, Chunhui; Xu, Fan; Lin, Zaishan; Qin, Yuyang; Li, Ying; Yang, Minglong; He, Xiaodong; Peng, Qingyu; Li, Yibin

2016-07-06

The creation of stiff yet multifunctional three-dimensional porous carbon architecture at very low cost is still challenging. In this work, lightweight and stiff carbon foam (CF) with adjustable pore structure was prepared by using flour as the basic element via a simple fermentation and carbonization process. The compressive strength of CF exhibits a high value of 3.6 MPa whereas its density is 0.29 g/cm(3) (compressive modulus can be 121 MPa). The electromagnetic interference (EMI) shielding effectiveness measurements (specific EMI shielding effectiveness can be 78.18 dB·cm(3)·g(-1)) indicate that CF can be used as lightweight, effective shielding material. Unlike ordinary foam structure materials, the low thermal conductivity (lowest is 0.06 W/m·K) with high resistance to fire makes CF a good candidate for commercial thermal insulation material. These results demonstrate a promising method to fabricate an economical, robust carbon material for applications in industry as well as topics regarding environmental protection and improvement of energy efficiency.

Comparison of blueberry powder produced via foam-mat freeze-drying versus spray-drying: evaluation of foam and powder properties.

Science.gov (United States)

Darniadi, Sandi; Ho, Peter; Murray, Brent S

2018-03-01

Blueberry juice powder was developed via foam-mat freeze-drying (FMFD) and spray-drying (SD) via addition of maltodextrin (MD) and whey protein isolate (WPI) at weight ratios of MD/WPI = 0.4 to 3.2 (with a fixed solids content of 5 wt% for FMFD and 10 wt% for SD). Feed rates of 180 and 360 mL h -1 were tested in SD. The objective was to evaluate the effect of the drying methods and carrier agents on the physical properties of the corresponding blueberry powders and reconstituted products. Ratios of MD/WPI = 0.4, 1.0 and 1.6 produced highly stable foams most suitable for FMFD. FMFD gave high yields and low bulk density powders with flake-like particles of large size that were also dark purple with high red values. SD gave low powder recoveries. The powders had higher bulk density and faster rehydration times, consisting of smooth, spherical and smaller particles than in FMFD powders. The SD powders were bright purple but less red than FMFD powders. Solubility was greater than 95% for both FMFD and SD powders. The FMFD method is a feasible method of producing blueberry juice powder and gives products retaining more characteristics of the original juice than SD. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Cellular morphology of organic-inorganic hybrid foams based on alkali alumino-silicate matrix

Science.gov (United States)

Verdolotti, Letizia; Liguori, Barbara; Capasso, Ilaria; Caputo, Domenico; Lavorgna, Marino; Iannace, Salvatore

2014-05-01

Organic-inorganic hybrid foams based on an alkali alumino-silicate matrix were prepared by using different foaming methods. Initially, the synthesis of an inorganic matrix by using aluminosilicate particles, activated through a sodium silicate solution, was performed at room temperature. Subsequently the viscous paste was foamed by using three different methods. In the first method, gaseous hydrogen produced by the oxidization of Si powder in an alkaline media, was used as blowing agent to generate gas bubbles in the paste. In the second method, the porous structure was generated by mixing the paste with a "meringue" type of foam previously prepared by whipping, under vigorous stirring, a water solution containing vegetal proteins as surfactants. In the third method, a combination of these two methods was employed. The foamed systems were consolidated for 24 hours at 40°C and then characterized by FTIR, X-Ray diffraction, scanning electron microscopy (SEM) and compression tests. Low density foams (˜500 Kg/m3) with good cellular structure and mechanical properties were obtained by combining the "meringue" approach with the use of the chemical blowing agent based on Si.

The use of castor oil polyurethane foam in impact limiters for radioactive materials packages

International Nuclear Information System (INIS)

Mouro, R.P.; Neto, M.M.

2003-01-01

This paper presents ongoing research aiming to assess the use of a 'bio based' polyurethane foam as filling material in impact limiters for transport packages in the nuclear field. The foam is made from castor oil, which replaces the petroleum based polyols in the manufacture of polyurethane products, with good environmental advantages. The research comprises the selection of the cellular material, its structural characterisation by mechanical laboratory tests, the development of a case study, preliminary determination of the best foam density for the case study, performance of the case and its numerical simulation using the finite element method. Prototypes with foam density that is pre-determined as ideal, as well as prototypes using lighter and heavier foams, were tested for comparison. The results obtained validate the research methodology, as expectations about the ideal foam density were confirmed by the drop tests and the numerical simulation. (author)

Cellular Response to Doping of High Porosity Foamed Alumina with Ca, P, Mg, and Si

Directory of Open Access Journals (Sweden)

Edwin Soh

2015-03-01

Full Text Available Foamed alumina was previously synthesised by direct foaming of sulphate salt blends varying ammonium mole fraction (AMF, foaming heating rate and sintering temperature. The optimal product was produced with 0.33AMF, foaming at 100 °C/h and sintering at 1600 °C. This product attained high porosity of 94.39%, large average pore size of 300 µm and the highest compressive strength of 384 kPa. To improve bioactivity, doping of porous alumina by soaking in dilute or saturated solutions of Ca, P, Mg, CaP or CaP + Mg was done. Saturated solutions of Ca, P, Mg, CaP and CaP + Mg were made with excess salt in distilled water and decanted. Dilute solutions were made by diluting the 100% solution to 10% concentration. Doping with Si was done using the sol gel method at 100% concentration only. Cell culture was carried out with MG63 osteosarcoma cells. Cellular response to the Si and P doped samples was positive with high cell populations and cell layer formation. The impact of doping with phosphate produced a result not previously reported. The cellular response showed that both Si and P doping improved the biocompatibility of the foamed alumina.

Hydrothermal growth of hierarchical Ni3S2 and Co3S4 on a reduced graphene oxide hydrogel@Ni foam: a high-energy-density aqueous asymmetric supercapacitor.

Science.gov (United States)

Ghosh, Debasis; Das, Chapal Kumar

2015-01-21

Ni foam@reduced graphene oxide (rGO) hydrogel-Ni3S2 and Ni foam@rGO hydrogel-Co3S4 composites have been successfully synthesized with the aid of a two-step hydrothermal protocol, where the rGO hydrogel is sandwiched between the metal sulfide and Ni foam substrate. Sonochemical deposition of exfoliated rGO on Ni foam with subsequent hydrothermal treatment results in the formation of a rGO-hydrogel-coated Ni foam. Then second-time hydrothermal treatment of the dried Ni@rGO substrate with corresponding metal nitrate and sodium sulfide results in individual uniform growth of porous Ni3S2 nanorods and a Co3S4 self-assembled nanosheet on a Ni@rGO substrate. Both Ni@rGO-Ni3S2 and Ni@rGO-Co3S4 have been electrochemically characterized in a 6 M KOH electrolyte, exhibiting high specific capacitance values of 987.8 and 1369 F/g, respectively, at 1.5 A/g accompanied by the respective outstanding cycle stability of 97.9% and 96.6% at 12 A/g over 3000 charge-discharge cycles. An advanced aqueous asymmetric (AAS) supercapacitor has been fabricated by exploiting the as-prepared Ni@rGO-Co3S4 as a positive electrode and Ni@rGO-Ni3S2 as a negative electrode. The as-fabricated AAS has shown promising energy densities of 55.16 and 24.84 Wh/kg at high power densities of 975 and 13000 W/kg, respectively, along with an excellent cycle stability of 96.2% specific capacitance retention over 3000 charge-discharge cycles at 12 A/g. The enhanced specific capacitance, stupendous cycle stability, elevated energy density, and a power density as an AAS of these electrode materials indicate that it could be a potential candidate in the field of supercapacitors.

Fracture Behavior of Adhesive-Bonded Aluminum Foam with Double Cantilever Beam

Energy Technology Data Exchange (ETDEWEB)

Bang, Hye-jin; Lee, Sang-kyo; Cho, Chongdu; Choi, Hae-kyu [Inha University, Incheon (Korea, Republic of); Cho, Jae-ung [Kongju University, Gongju (Korea, Republic of)

2014-05-15

In this study, closed-cell aluminum foam with an initial crack was investigated to produce an axial load-time graph. Using the 10-kN Landmarks of MTS Corporation, a 15-mm/min velocity of mode I shape was applied to the aluminum foam specimen using the displacement control method. ABAQUS 6.10 simulation was used to model and analyze the identical model in three dimensions under conditions identical to those of the experiment. The energy release rate was calculated on the basis of an axial load-displacement graph obtained from the experiment and a transient image of the crack length, and then an FE model was analyzed on the basis of this fracture energy condition. The relation between load and displacement was discussed; it was found that the aluminum foam deformed somewhat less than the adhesive layer owing to the difference in elastic modulus.

Fracture Behavior of Adhesive-Bonded Aluminum Foam with Double Cantilever Beam

International Nuclear Information System (INIS)

Bang, Hye-jin; Lee, Sang-kyo; Cho, Chongdu; Choi, Hae-kyu; Cho, Jae-ung

2014-01-01

In this study, closed-cell aluminum foam with an initial crack was investigated to produce an axial load-time graph. Using the 10-kN Landmarks of MTS Corporation, a 15-mm/min velocity of mode I shape was applied to the aluminum foam specimen using the displacement control method. ABAQUS 6.10 simulation was used to model and analyze the identical model in three dimensions under conditions identical to those of the experiment. The energy release rate was calculated on the basis of an axial load-displacement graph obtained from the experiment and a transient image of the crack length, and then an FE model was analyzed on the basis of this fracture energy condition. The relation between load and displacement was discussed; it was found that the aluminum foam deformed somewhat less than the adhesive layer owing to the difference in elastic modulus

A general synthesis strategy for the multifunctional 3D polypyrrole foam of thin 2D nanosheets

Science.gov (United States)

Xue, Jiangli; Mo, Maosong; Liu, Zhuming; Ye, Dapeng; Cheng, Zhihua; Xu, Tong; Qu, Liangti

2018-05-01

A 3D macroporous conductive polymer foam of thin 2D polypyrrole (PPy) nanosheets is developed by adopting a novel intercalation of guest (monomer Py) between the layers of the lamellar host (3D vanadium oxide foam) template-replication strategy. The 3D PPy foam of thin 2D nanosheets exhibits diverse functions including reversible compressibility, shape memory, absorption/adsorption and mechanically deformable supercapacitor characteristics. The as-prepared 3D PPy foam of thin nanosheets is highly light weight with a density of 12 mg·cm-3 which can bear the large compressive strain up to 80% whether in wet or dry states; and can absorb organic solutions or extract dye molecules fast and efficiently. In particular, the PPy nanosheet-based foamas a mechanically deformable electrode material for supercapacitors exhibits high specific capacitance of 70 F·g-1 at a fast charge-discharge rate of 50 mA·g-1, superior to that of any other typical pure PPy-based capacitor. We envision that the strategy presented here should be applicable to fabrication of a wide variety of organic polymer foams and hydrogels of low-dimensional nanostructures and even inorganic foams and hydrogels of low-dimensional nanostructures, and thus allow for exploration of their advanced physical and chemical properties.

Amalgamation of Chlamydia pneumoniae inclusions with lipid droplets in foam cells in human atherosclerotic plaque.

Science.gov (United States)

Bobryshev, Yuri V; Killingsworth, Murray C; Tran, Dihn; Lord, Reginald

2008-07-01

Chlamydia pneumoniae (Chlamydophila pneumoniae) infect macrophages and accelerates foam cell formation in in vitro experiments, but whether this might occur in human atherosclerosis is unknown. In the present study, we examined 17 carotid artery segments, obtained by endarterectomy, in which the presence of C. pneumoniae was confirmed by both polymerase chain reaction and immunohistochemistry. Electron microscopy demonstrated the presence of structures with the appearance of elementary, reticulate and aberrant bodies of C. pneumoniae in the cytoplasm of macrophage foam cells. The volume of the cytoplasm that was free from vacuoles and lipid droplets in C. pneumoniae-infected foam cells was dramatically reduced, and a phenomenon of the amalgamation of C. pneumoniae inclusions with lipid droplets was detected. Double immunohistochemistry showed that C. pneumoniae-infected foam cells contained a large number of oxidized low-density lipoproteins. The observations provide support to the hypothesis that C. pneumoniae could affect foam cell formation in human atherosclerosis.

Polyimide Foams Offer Superior Insulation

Science.gov (United States)

2012-01-01

At Langley Research Center, Erik Weiser and his colleagues in the Advanced Materials and Processing Branch were working with a new substance for fabricating composites for use in supersonic aircraft. The team, however, was experiencing some frustration. Every time they tried to create a solid composite from the polyimide (an advanced polymer) material, it bubbled and foamed. It seemed like the team had reached a dead end in their research - until they had another idea. "We said, This isn t going to work for composites, but maybe we could make a foam out of it," Weiser says. "That was kind of our eureka moment, to see if we could go in a whole other direction. And it worked." Weiser and his colleagues invented a new kind of polyimide foam insulation they named TEEK. The innovation displayed a host of advantages over existing insulation options. Compared to other commercial foams, Weiser explains, polyimide foams perform well across a broad range of temperatures, noting that the NASA TEEK foams provide effective structural insulation up to 600 F and down to cryogenic temperatures. The foam does not burn or off-gas toxic fumes, and even at -423 F - the temperature of liquid hydrogen - the material stays flexible. The inventors could produce the TEEK foam at a range of densities, from 0.5 pounds per cubic foot up to 20 pounds per cubic foot, making the foam ideal for a range of applications, including as insulation for reusable launch vehicles and for cryogenic tanks and lines. They also developed a unique, friable balloon format for manufacturing the foam, producing it as hollow microspheres that allowed the foam to be molded and then cured into any desired shape - perfect for insulating pipes of different sizes and configurations. The team s originally unplanned invention won an "R&D 100" award, and a later form of the foam, called LaRC FPF-44 (Spinoff 2009), was named "NASA Invention of the Year" in 2007.

Analysis of compaction shock interactions during DDT of low density HMX

Science.gov (United States)

Rao, Pratap T.; Gonthier, Keith A.

2017-01-01

Deflagration-to-Detonation Transition (DDT) in confined, low density granular HMX occurs by a complex mechanism that involves compaction shock interactions within the material. Piston driven DDT experiments indicate that detonation is abruptly triggered by the interaction of a strong combustion-supported secondary shock and a piston-supported primary (input) shock, where the nature of the interaction depends on initial packing density and primary shock strength. These interactions influence transition by affecting dissipative heating within the microstructure during pore collapse. Inert meso-scale simulations of successive shock loading of low density HMX are performed to examine how dissipation and hot-spot formation are affected by the initial density, and the primary and secondary shock strengths. This information is used to formulate an ignition and burn model for low density HMX that accounts for the effect of shock densensitization on burn. Preliminary DDT predictions are presented that illustrate how primary shock strength affects the transition mechanism.

Synthesis of Various Silica Nanoparticles for Foam Stability

International Nuclear Information System (INIS)

Yoon, Suk Bon; Yoon, Inho; Jung, Chonghun; Kim, Chorong; Choi, Wangkyu; Moon, Jeikwon

2013-01-01

The synthesis of the non-porous silica nanoparticles with uniform sizes has been reported through the Sto ber method, the synthesis of meso porous silica nanoparticles with a specific morphology such as core-shell, rod-like, and hexagonal shapes is not so common. As a synthetic strategy for controlling the particle size, shape, and porosity, the synthesis of core-shell silicas with meso porous shells formed on silica particle cores through the self-assembly of silica precursor and organic templates or spherical meso porous silicas using modified Sto ber method was also reported. Recently, in an effort to reduce the amount of radioactive waste and enhance the decontamination efficiency during the decontamination process of nuclear facilities contaminated with radionuclides, a few research for the preparation of the decontamination foam containing solid nanoparticles has been reported. In this work, the silica nanoparticles with various sizes, shapes, and structures were synthesized based on the previous literatures. The resulting silica nanoparticles were used to investigate the effect of the nanoparticles on the foam stability. In a study on the foam stability using various silica nanoparticles, the results showed that the foam volume and liquid volume in foam was enhanced when using a smaller size and lower density of the silica nanoparticles. Silica nanoparticles with various sizes, shapes, and structures such as a non-porous, meso porous core-shell, and meso porous silica were synthesized to investigate the effect of the foam stability. The sizes and structural properties of the silica nanoparticles were easily controlled by varying the amount of silica precursor, surfactant, and ammonia solution as a basic catalyst. The foam prepared using various silica nanoparticles showed that foam the volume and liquid volume in the foam were enhanced when using a smaller size and lower density of the silica nanoparticles

Data characterizing tensile behavior of cenosphere/HDPE syntactic foam.

Science.gov (United States)

Kumar, B R Bharath; Doddamani, Mrityunjay; Zeltmann, Steven E; Gupta, Nikhil; Ramakrishna, Seeram

2016-03-01

The data set presented is related to the tensile behavior of cenosphere reinforced high density polyethylene syntactic foam composites "Processing of cenosphere/HDPE syntactic foams using an industrial scale polymer injection molding machine" (Bharath et al., 2016) [1]. The focus of the work is on determining the feasibility of using an industrial scale polymer injection molding (PIM) machine for fabricating syntactic foams. The fabricated syntactic foams are investigated for microstructure and tensile properties. The data presented in this article is related to optimization of the PIM process for syntactic foam manufacture, equations and procedures to develop theoretical estimates for properties of cenospheres, and microstructure of syntactic foams before and after failure. Included dataset contains values obtained from the theoretical model.

Ceramic Foams from Pre-Ceramic Polymer Routes for Reusable Acreage Thermal Protection System Applications

Science.gov (United States)

Stackpoole, Mairead; Chien, Jennifer; Schaeffler, Michelle

2004-01-01

Contents include the following: Motivation. Current light weight insulation. Advantages of preceramic-polymer-derived ceramic foams. Rigid insulation materials. Tailor foam microstructures. Experimental approach. Results: sacrificial materials, sacrificial fillers. Comparison of foam microstructures. Density of ceramic foams. Phase evolution and properties: oxidation behavior. mechanical properties, aerothermal performance. Impact damage of microcellular foams. Conclusions.

A review of low add-on and foam application techniques

CSIR Research Space (South Africa)

Van der Walt, GHJ

1984-02-01

Full Text Available -February 1984 This application system consists of four major components: the engraved roller (A), a rubber roller (B), a doctor blade (C), and the liquor The engraved roller rotates in the liquor bath (D) where its cavities are ffled with Liquor...".'". 5.2 Different Systems for the AppUeatioa of Foam There are several basic mechanisms for the application of foam to textiles. The foam can be applied either to one side or both sides of the fabric. In the former case a doctor blade or knife, or a...

Real-Time Monitoring of Low-Level Mixed-Waste Loading during Polyethylene Microencapsulation using Transient Infrared Spectroscopy

International Nuclear Information System (INIS)

Jones, Roger W.; Kalb, Paul D.; McClelland, John F.; Ochiai, Shukichi

1999-01-01

In polyethylene microencapsulation, low-level mixed waste (LLMW) is homogenized with molten polyethylene and extruded into containers, resulting in a lighter, lower-volume waste form than cementation and grout methods produce. Additionally, the polyethylene-based waste form solidifies by cooling, with no risk of the waste interfering with cure, as may occur with cementation and grout processes. We have demonstrated real-time monitoring of the polyethylene encapsulation process stream using a noncontact device based on transient infrared spectroscopy (TIRS). TIRS can acquire mid-infrared spectra from solid or viscous liquid process streams, such as the molten, waste-loaded polyethylene stream that exits the microencapsulation extruder. The waste loading in the stream was determined from the TIRS spectra using partial least squares techniques. The monitor has been demonstrated during the polyethylene microencapsulation of nitrate-salt LLMW and its surrogate, molten salt oxidation LLMW and its surrogate, and flyash. The monitor typically achieved a standard error of prediction for the waste loading of about 1% by weight with an analysis time under 1 minute

Physiochemical properties and reproducibility of air-based sodium tetradecyl sulphate foam using the Tessari method.

Science.gov (United States)

Watkins, Mike R; Oliver, Richard J

2017-07-01

Objectives The objectives were to examine the density, bubble size distribution and durability of sodium tetradecyl sulphate foam and the consistency of production of foam by a number of different operators using the Tessari method. Methods 1% and 3% sodium tetradecyl sulphate sclerosant foam was produced by an experienced operator and a group of inexperienced operators using either a 1:3 or 1:4 liquid:air ratio and the Tessari method. The foam density, bubble size distribution and foam durability were measured on freshly prepared foam from each operator. Results The foam density measurements were similar for each of the 1:3 preparations and for each of the 1:4 preparations but not affected by the sclerosant concentration. The bubble size for all preparations were very small immediately after preparation but progressively coalesced to become a micro-foam (foams developed liquid more rapidly when made in a 1:3 ratio (37 s) than in a 1:4 ratio (45 s) but all combinations took similar times to reach 0.4 ml liquid formation. For all the experiments, there was no statistical significant difference between operators. Conclusions The Tessari method of foam production for sodium tetradecyl sulphate sclerosant is consistent and reproducible even when made by inexperienced operators. The best quality foam with micro bubbles should be used within the first minute after production.

The hydrodynamic and radiative properties of low-density foams heated by x-rays

Czech Academy of Sciences Publication Activity Database

Rosmej, O. N.; Suslov, N.; Martsovenko, D.; Vergunova, G.; Borisenko, N.; Orlov, N.; Rienecker, T.; Klír, Daniel; Řezáč, Karel; Orekhov, A.; Borisenko, L.; Krouský, Eduard; Pfeifer, Miroslav; Dudžák, Roman; Maeder, R.; Schaechinger, M.; Schoenlein, A.; Zaehter, S.; Jacoby, J.; Limpouch, J.; Ullschmied, Jiří; Zhidkov, N.

2015-01-01

Roč. 57, č. 9 (2015), č. článku 094001. ISSN 0741-3335 R&D Projects: GA MŠk(CZ) LG13029; GA MŠk LM2010014 Grant - others:FP7(XE) 284464 Program:FP7 Institutional support: RVO:61389021 Keywords : hohlraum * low density polymer aerogel * opacity * Planckian radiation * plasma * x-rays Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.404, year: 2015 http://iopscience.iop.org/article/10.1088/0741-3335/57/9/094001;jsessionid=E4079D2364DFCC5CA64FBF3B9F73D180.c2.iopscience.cld.iop.org

On-Demand Microwave-Assisted Fabrication of Gelatin Foams

Directory of Open Access Journals (Sweden)

Shane D. Frazier

2018-05-01

Full Text Available Ultraporous gelatin foams (porosity >94%, ρ ≈ 0.039–0.056 g/cm3 have been fabricated via microwave radiation. The resulting foam structures are unique with regard to pore morphology (i.e., closed-cell and exhibit 100% macroporosity (pore size 332 to 1700 μm, presence of an external skin, and densities similar to aerogels. Results indicate that the primary foaming mechanism is governed by the vaporization of water that is tightly bound in secondary structures (i.e., helices, β-turns, β-sheets that are present in dehydrated gelatin films but not present in the foams after microwave radiation (700 Watts.

RF Loads for Energy Recovery

CERN Document Server

Federmann, S; Caspers, F

2012-01-01

Different conceptional designs for RF high power loads are presented. One concept implies the use of solid state rectifier modules for direct RF to DC conversion with efficiencies beyond 80%. In addition, robust metallic low-Q resonant structures, capable of operating at high temperatures (>150 ◦C) are discussed. Another design deals with a very high temperature (up to 800 ◦C) air cooled load using a ceramic foam block inside a metal enclosure. This porous ceramic block is the microwave absorber and is not brazed to the metallic enclosure.

Pitch-based carbon foam and composites and use thereof

Science.gov (United States)

Klett, James W.; Burchell, Timothy D.; Choudhury, Ashok

2006-07-04

A thermally conductive carbon foam is provided, normally having a thermal conductivity of at least 40 W/mK. The carbon foam usually has a specific thermal conductivity, defined as the thermal conductivity divided by the density, of at least about 75 Wcm.sup.3/m.degree. Kgm. The foam also has a high specific surface area, typically at least about 6,000 m.sup.2/m.sup.3. The foam is characterized by an x-ray diffraction pattern having "doublet" 100 and 101 peaks characterized by a relative peak split factor no greater than about 0.470. The foam is graphitic and exhibits substantially isotropic thermal conductivity. The foam comprises substantially ellipsoidal pores and the mean pore diameter of such pores is preferably no greater than about 340 microns. Other materials, such as phase change materials, can be impregnated in the pores in order to impart beneficial thermal properties to the foam. Heat exchange devices and evaporatively cooled heat sinks utilizing the foams are also disclosed.

Preparation of sintered foam materials by alkali-activated coal fly ash.

Science.gov (United States)

Zhao, Yelong; Ye, Junwei; Lu, Xiaobin; Liu, Mangang; Lin, Yuan; Gong, Weitao; Ning, Guiling

2010-02-15

Coal fly ash from coal fired power stations is a potential raw material for the production of ceramic tiles, bricks and blocks. Previous works have demonstrated that coal fly ash consists mainly of glassy spheres that are relatively resistant to reaction. An objective of this research was to investigate the effect of alkali on the preparation process of the foam material. Moreover, the influence of foam dosage on the water absorption, apparent density and compressive strength was evaluated. The experimental results showed that homogenous microstructures of interconnected pores could be obtained by adding 13 wt.% foaming agent at 1050 degrees C, leading to foams presenting water absorption, apparent density and compressive strength values of about 126.5%, 0.414 g/cm(3), 6.76 MPa, respectively.

Generalization of the memory integer model for the analysis of the quasi-static behaviour of polyurethane foams

International Nuclear Information System (INIS)

Jmal, Hamdi; Ju, Ming Lei; Dupuis, Raphael; Aubry, Evelyne

2014-01-01

Polyurethane foam is a cellular material characterized by an interesting mechanical spectrum of properties: low density, capacity to absorb the deformation energy and low stiffness. This spectrum of properties makes polyurethane foam commonly used in many thermal, acoustic and comfort applications. Several models, such as memory, hyper-elastic and pseudo-elastic models have been developed in the literature to describe the mechanical response of polyurethane foam under quasi-static and dynamic test conditions. The main disadvantage of these models is the dependence of their parameters against the test conditions (strain rate, maximum compression level, etc). This affects the general character of their representativeness to the quasi-static and dynamic behaviours of polyurethane foam. The main goal of this article is to implement reliable mechanical model which is able to provide the quasi-static response of the polyurethane foam under different strain rates and large compressive deformation. The dimensional parameters of our model can be expressed by the product of two independent parts; the first contain only the test conditions and the second define the dimensionless and invariant parameters that characterize the foam material. The developed model has been proposed after several experimental studies allowing the apprehension of the quasi-static behaviour (through unidirectional compression tests). The polyurethane foam, under large deformations, exhibits a nonlinear elastic behaviour and viscoelastic behaviour. To assess the ability of our model to be a general representation, three industrial polyurethane foams have been considered.

saltPAD: A New Analytical Tool for Monitoring Salt Iodization in Low Resource Settings

Directory of Open Access Journals (Sweden)

Nicholas M. Myers

2016-03-01

Full Text Available We created a paper test card that measures a common iodizing agent, iodate, in salt. To test the analytical metrics, usability, and robustness of the paper test card when it is used in low resource settings, the South African Medical Research Council and GroundWork performed independ‐ ent validation studies of the device. The accuracy and precision metrics from both studies were comparable. In the SAMRC study, more than 90% of the test results (n=1704 were correctly classified as corresponding to adequately or inadequately iodized salt. The cards are suitable for market and household surveys to determine whether salt is adequately iodized. Further development of the cards will improve their utility for monitoring salt iodization during production.

High coupling efficiency of foam spherical hohlraum driven by 2ω laser light

Science.gov (United States)

Chen, Yao-Hua; Lan, Ke; Zheng, Wanguo; Campbell, E. M.

2018-02-01

The majority of solid state laser facilities built for laser fusion research irradiate targets with third harmonic light (0.35 μm) up-converted from the fundamental Nd wavelength at 1.05 μm. The motivation for this choice of wavelength is improved laser-plasma coupling. Significant disadvantages to this choice of wavelength are the reduced damage threshold of optical components and the efficiency of energy conversion to third harmonic light. Both these issues are significantly improved if second harmonic (0.53 μm) radiation is used, but theory and experiments have shown lower optical to x-ray energy conversion efficiency and increased levels of laser-plasma instabilities, resulting in reduced laser-target coupling. In this letter, we propose to use a 0.53 μm laser for the laser ignition facilities and use a low density foam wall to increase the coupling efficiency from the laser to the capsule and present two-dimensional radiation-hydrodynamic simulations of 0.53 μm laser light irradiating an octahedral-spherical hohlraum with a low density foam wall. The simulations show that the reduced optical depth of the foam wall leads to an increased laser-light conversion into thermal x-rays and about 10% higher radiation flux on the capsule than that achieved with 0.35 μm light irradiating a solid density wall commonly used in laser indirect drive fusion research. The details of the simulations and their implications and suggestions for wavelength scaling coupled with innovative hohlraum designs will be discussed.

Pullout strength of bone-patellar tendon-bone allograft bone plugs: a comparison of cadaver tibia and rigid polyurethane foam.

Science.gov (United States)

Barber, F Alan

2013-09-01

To compare the load-to-failure pullout strength of bone-patellar tendon-bone (BPTB) allografts in human cadaver tibias and rigid polyurethane foam blocks. Twenty BPTB allografts were trimmed creating 25 mm × 10 mm × 10 mm tibial plugs. Ten-millimeter tunnels were drilled in 10 human cadaver tibias and 10 rigid polyurethane foam blocks. The BPTB anterior cruciate ligament allografts were inserted into these tunnels and secured with metal interference screws, with placement of 10 of each type in each material. After preloading (10 N), cyclic loading (500 cycles, 10 to 150 N at 200 mm/min) and load-to-failure testing (200 mm/min) were performed. The endpoints were ultimate failure load, cyclic loading elongation, and failure mode. No difference in ultimate failure load existed between grafts inserted into rigid polyurethane foam blocks (705 N) and those in cadaver tibias (669 N) (P = .69). The mean rigid polyurethane foam block elongation (0.211 mm) was less than that in tibial bone (0.470 mm) (P = .038), with a smaller standard deviation (0.07 mm for foam) than tibial bone (0.34 mm). All BPTB grafts successfully completed 500 cycles. The rigid polyurethane foam block showed less variation in test results than human cadaver tibias. Rigid polyurethane foam blocks provide an acceptable substitute for human cadaver bone tibia for biomechanical testing of BPTB allografts and offer near-equivalent results. Copyright © 2013 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Auxetic Polyurethane Foam (Fabrication, Properties and Applications)