WorldWideScience

Sample records for foam fitted aisi

  1. The significance of passivation treatments on AISI 314 foam pieces to be used as substrates for catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Bortolozzi, J.P.; Banus, E.D.; Milt, V.G.; Gutierrez, L.B. [Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Ulla, M.A., E-mail: mulla@fiq.unl.edu.ar [Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina)

    2010-11-01

    Several properties of metallic foams such as their low density, high mechanical strength and good coefficients of heat and mass transfer make them attractive for applications in catalysis. Important modifications in the composition and morphology of the metallic foam surfaces can take place when they are submitted to treatments at high temperatures. These surface changes are due to the migration of some elements from the metallic core to the pore surface, thus inducing a passivation via an oxide layer formation. This new layer avoids further metallic segregation and generates a surface roughness, both effects having a significant impact on the catalytic coating quality. This work analyzes the effects of calcination temperature and time on the chemistry and morphology of the metallic surface corresponding to the AISI 314 stainless steel foams of 50 and 60 ppi. The chemical and morphological surface changes were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray (EDX) analysis and Laser Raman Spectroscopy (LRS). The application of high temperature treatments on AISI 314 foams promotes the formation of a surface layer containing chromium oxide and spinel-type compounds of chromium, iron and manganese. The optimum treatment temperature for this type of structures seems to be 900 deg. C because both the adhesion and thickness of the layer formed are adequate. For the sample with smaller pores (60 ppi) the optimal treatment time is close to 2 h and for that with larger pores (50 ppi) the recommended time is 20 h. Under these conditions, a compromise is found between adhesion, thickness and surface roughness, suitable for the subsequent deposition of catalytic material.

  2. Surface fatigue and failure characteristics of hot-forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

    Science.gov (United States)

    Townsend, Dennis P.

    1987-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground AISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  3. Surface fatigue and failure characteristics of hot forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

    Science.gov (United States)

    Townsend, D. P.

    1986-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground SISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  4. Foaming volume and foam stability

    Science.gov (United States)

    Ross, Sydney

    1947-01-01

    A method of measuring foaming volume is described and investigated to establish the critical factors in its operation. Data on foaming volumes and foam stabilities are given for a series of hydrocarbons and for a range of concentrations of aqueous ethylene-glycol solutions. It is shown that the amount of foam formed depends on the machinery of its production as well as on properties of the liquid, whereas the stability of the foam produced, within specified mechanical limitations, is primarily a function of the liquid.

  5. Parameters affect foaming and foam stability during foam drilling

    Institute of Scientific and Technical Information of China (English)

    Hazaea Mohammed; Youhong SUN; Ould El Houssein Yarbana

    2007-01-01

    The authors presented indoor practice experiments of parameters affect on foaming and foam stability. Experiments were carried out and special equipments were used to determine foaming and foam stability; tests were tabulated and charted. The effects of chemical and physical parameters on foaming and foam stability have been conducted.

  6. Foaming properties of guar foaming albumin

    OpenAIRE

    細見, 典子; Hosomi, Noriko; 原田, 麻子; Harada, Asako; 下山, 亜美; Shimoyama, Ami; 土居, 幸雄; Doi, Yukio

    2009-01-01

    From guar meal we recently isolated an albumin fraction with a high foaming ability, named guar foaming albumin (GFA) . Here, we further characterized the foaming activity, foam stability and surface tension of GFA solutions. Foaming activity and foam stability were estimated by measuring the conductivity of foam using a glass column with a conductivity cell. Surface tension was measured by the drop weight method using a stalagmometer. GFA showed higher foaming activity than casein at any pro...

  7. Spin foams

    CERN Document Server

    Engle, Jonathan

    2013-01-01

    The spin foam framework provides a way to define the dynamics of canonical loop quantum gravity in a spacetime covariant way, by using a path integral over histories of quantum states which can be interpreted as `quantum space-times'. This chapter provides a basic introduction to spin foams aimed principally at beginning graduate students and, where possible, at broader audiences.

  8. Comparative study of high temperature oxidation behaviour in AISI 304 and AISI 439 stainless steels

    Directory of Open Access Journals (Sweden)

    Antônio Claret Soares Sabioni

    2003-06-01

    Full Text Available This work deals with a comparison of high temperature oxidation behaviour in AISI 304 austenitic and AISI 439 ferritic stainless steels. The oxidation experiments were performed between 850 and 950 °C, in oxygen and Ar (100 vpm H2. In most cases, it was formed a Cr2O3 protective scale, whose growth kinetics follows a parabolic law. The exception was for the the AISI 304 steel, at 950 °C, in oxygen atmosphere, which forms an iron oxide external layer. The oxidation resistance of the AISI 439 does not depend on the atmosphere. The AISI 304 has the same oxidation resistance in both atmospheres, at 850 °C, but at higher temperatures, its oxidation rate strongly increases in oxygen atmosphere. Concerning the performance of these steels under oxidation, our results show that the AISI 439 steel has higher oxidation resistance in oxidizing atmosphere, above 850 °C, while, in low pO2 atmosphere, the AISI 304 steel has higher oxidation resistance than the AISI 439, in all the temperature range investigated.

  9. Comparing the Formability of AISI 304 and AISI 202 Stainless Steels

    Science.gov (United States)

    du Toit, M.; Steyn, H. G.

    2012-07-01

    The formability of AISI 202 austenitic stainless steel was compared with that of type AISI 304 stainless steel. Type 202 is a low-nickel austenitic stainless steel alloyed with manganese and nitrogen. In this study, the formability of the two grades was examined using Erichsen cupping tests and room temperature uniaxial tensile tests performed at various angles to the rolling direction. AISI 202 appears to work-harden at a slightly higher rate than AISI 304, even though the austenite in type 202 is more stable than that in 304 with respect to the formation of deformation-induced α' martensite. Although both grades are predicted to be susceptible to earing during deep drawing, AISI 202 displays a higher work-hardening exponent, higher average normal anisotropy, and a higher limiting drawing ratio than AISI 304. Similar cup heights were measured during Erichsen cupping tests, confirming that the two grades have very similar deep drawing properties. The results of this investigation therefore suggest that AISI 202 is a suitable alternative for AISI 304 in applications requiring good deep drawing properties.

  10. Forming foam structures with carbon foam substrates

    Science.gov (United States)

    Landingham, Richard L.; Satcher, Jr., Joe H.; Coronado, Paul R.; Baumann, Theodore F.

    2012-11-06

    The invention provides foams of desired cell sizes formed from metal or ceramic materials that coat the surfaces of carbon foams which are subsequently removed. For example, metal is located over a sol-gel foam monolith. The metal is melted to produce a metal/sol-gel composition. The sol-gel foam monolith is removed, leaving a metal foam.

  11. Foam patterns

    Science.gov (United States)

    Chaudhry, Anil R; Dzugan, Robert; Harrington, Richard M; Neece, Faurice D; Singh, Nipendra P; Westendorf, Travis

    2013-11-26

    A method of creating a foam pattern comprises mixing a polyol component and an isocyanate component to form a liquid mixture. The method further comprises placing a temporary core having a shape corresponding to a desired internal feature in a cavity of a mold and inserting the mixture into the cavity of the mold so that the mixture surrounds a portion of the temporary core. The method optionally further comprises using supporting pins made of foam to support the core in the mold cavity, with such pins becoming integral part of the pattern material simplifying subsequent processing. The method further comprises waiting for a predetermined time sufficient for a reaction from the mixture to form a foam pattern structure corresponding to the cavity of the mold, wherein the foam pattern structure encloses a portion of the temporary core and removing the temporary core from the pattern independent of chemical leaching.

  12. Foam Microrheology

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-09-01

    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.

  13. Foam Micromechanics

    Energy Technology Data Exchange (ETDEWEB)

    Kraynik, A.M.; Neilsen, M.K.; Reinelt, D.A.; Warren, W.E.

    1998-11-03

    Foam evokes many different images: waves breaking at the seashore, the head on a pint of Guinness, an elegant dessert, shaving, the comfortable cushion on which you may be seated... From the mundane to the high tech, foams, emulsions, and cellular solids encompass a broad range of materials and applications. Soap suds, mayonnaise, and foamed polymers provide practical motivation and only hint at the variety of materials at issue. Typical of mukiphase materiaIs, the rheoIogy or mechanical behavior of foams is more complicated than that of the constituent phases alone, which may be gas, liquid, or solid. For example, a soap froth exhibits a static shear modulus-a hallmark of an elastic solid-even though it is composed primarily of two Newtonian fluids (water and air), which have no shear modulus. This apparent paradox is easily resolved. Soap froth contains a small amount of surfactant that stabilizes the delicate network of thin liq- uid films against rupture. The soap-film network deforms in response to a macroscopic strain; this increases interracial area and the corresponding sur- face energy, and provides the strain energy of classical elasticity theory [1]. This physical mechanism is easily imagined but very challenging to quantify for a realistic three-dimensional soap froth in view of its complex geome- try. Foam micromechanics addresses the connection between constituent properties, cell-level structure, and macroscopic mechanical behavior. This article is a survey of micromechanics applied to gas-liquid foams, liquid-liquid emulsions, and cellular solids. We will focus on static response where the foam deformation is very slow and rate-dependent phenomena such as viscous flow can be neglected. This includes nonlinear elasticity when deformations are large but reversible. We will also discuss elastic- plastic behavior, which involves yield phenomena. Foam structures based on polyhedra packed to fill space provide a unify- ing geometrical theme. Because a two

  14. Activated, coal-based carbon foam

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Darren Kenneth; Plucinski, Janusz Wladyslaw

    2004-12-21

    An ablation resistant, monolithic, activated, carbon foam produced by the activation of a coal-based carbon foam through the action of carbon dioxide, ozone or some similar oxidative agent that pits and/or partially oxidizes the carbon foam skeleton, thereby significantly increasing its overall surface area and concurrently increasing its filtering ability. Such activated carbon foams are suitable for application in virtually all areas where particulate or gel form activated carbon materials have been used. Such an activated carbon foam can be fabricated, i.e. sawed, machined and otherwise shaped to fit virtually any required filtering location by simple insertion and without the need for handling the "dirty" and friable particulate activated carbon foam materials of the prior art.

  15. Activated, coal-based carbon foam

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Darren Kenneth [Wheeling, WV; Plucinski, Janusz Wladyslaw [Glen Dale, WV

    2009-06-09

    An ablation resistant, monolithic, activated, carbon foam produced by the activation of a coal-based carbon foam through the action of carbon dioxide, ozone or some similar oxidative agent that pits and/or partially oxidizes the carbon foam skeleton, thereby significantly increasing its overall surface area and concurrently increasing its filtering ability. Such activated carbon foams are suitable for application in virtually all areas where particulate or gel form activated carbon materials have been used. Such an activated carbon foam can be fabricated, i.e. sawed, machined and otherwise shaped to fit virtually any required filtering location by simple insertion and without the need for handling the "dirty" and friable particulate activated carbon foam materials of the prior art.

  16. An investigation on weldability of AISI 304 and AISI 1040 steels on friction welding; Untersuchung der Schweisseignung von AISI 304 und AISI 1040 mittels Reibschweissen

    Energy Technology Data Exchange (ETDEWEB)

    Celik, Sare; Ay, Irfan [Balikesir Univ., Cagis Campus (Turkey). Mechanical Eng. Dept.; Dinc, Dincer [General Directorate of Highways, Canakkale (Turkey); Yaman, Ramazan [Balikesir Univ., Cagis Campus (Turkey). Industrial Eng. Dept.

    2010-04-15

    In welding technology, joining processes of different materials, which have dissimilar crystal structures are difficult. Welding of different materials becomes very important to reduce costs. Furthermore, the friction welding method is processed in lower temperature than the melting temperature. Especially, this is a big advantage to overcome difficulties that occur in the heat affected zone during usage of conventional methods. In this study, the weldability of AISI 304 stainless steel and AISI 1040 carbon steel by friction welding is studied. During the welding process, temperature variations in the welding zones were measured with an infrared temperature measurement device. After welding of the samples, tensile and hardness experiments were carried out. For metallographic investigations, optical microscope and scanning electron microscope (SEM) pictures were taken. Energy dispersive spectroscopy (EDS) analysis was carried out for composition investigations on welding and heat affected zones. As a result, these two steels could be joined by friction welding for industrial usage.

  17. State on AISI 304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    A. Fattah-alhosseini

    2011-01-01

    Full Text Available The passivity and protective nature of the passive films are essentially related to ionic and electronic transport processes, which are controlled by the optical and electronic properties of passive films. In this study, the electrochemical behavior of passive films anodically formed on AISI 304 stainless steel in sulfuric acid solution has been examined using electrochemical impedance spectroscopy. AISI 304 in sulphuric acid solution is characterized by high interfacial impedance, thereby illustrating its high corrosion resistance. Results showed that the interfacial impedance and the polarization resistance (pol initially increase with applied potential, within the low potential passive. However, at a sufficiently high potential passive (>0.4 V, the interfacial impedance and the polarization resistance decrease with increasing potential. An electrical equivalent circuit based on the impedance analysis, which describes the behavior of the passive film on stainless steel more satisfactorily than the proposed models, is presented.

  18. Foam Cushioning

    Science.gov (United States)

    1988-01-01

    One innovation developed by a contractor at Ames Research Center was an open cell polymeric foam material with unusual properties. Intended as padding for aircraft seats the material offered better impact protection against accidents, and also enhanced passenger comfort because it distributed body weight evenly over the entire contact area. Called a slow springback foam, it flows to match the contour of the body pressing against it, and returns to its original shape once the pressure is removed. It has many applications including aircraft cushions and padding, dental stools, and athletic equipment. Now it's used by Dynamic Systems, Inc. for medical applications such as wheel chairs for severely disabled people which allow them to sit for 3-8 hours where they used to be uncomfortable in 15-30 minutes.

  19. Characterization of AISI 4140 borided steels

    Energy Technology Data Exchange (ETDEWEB)

    Campos-Silva, I., E-mail: icampos@ipn.mx [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico); Ortiz-Dominguez, M.; Lopez-Perrusquia, N.; Meneses-Amador, A. [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico); Escobar-Galindo, R. [Instituto de Ciencia de Materiales de Madrid (CSIC), E-28049 Cantoblanco, Madrid (Spain); Martinez-Trinidad, J. [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico)

    2010-02-01

    The present study characterizes the surface of AISI 4140 steels exposed to the paste-boriding process. The formation of Fe{sub 2}B hard coatings was obtained in the temperature range 1123-1273 K with different exposure times, using a 4 mm thick layer of boron carbide paste over the material surface. First, the growth kinetics of boride layers at the surface of AISI 4140 steels was evaluated. Second, the presence and distribution of alloying elements on the Fe{sub 2}B phase was measured using the Glow Discharge Optical Emission Spectrometry (GDOES) technique. Further, thermal residual stresses produced on the borided phase were evaluated by X-ray diffraction (XRD) analysis. The fracture toughness of the iron boride layer of the AISI 4140 borided steels was estimated using a Vickers microindentation induced-fracture testing at a constant distance of 25 {mu}m from the surface. The force criterion of fracture toughness was determined from the extent of brittle cracks, both parallel and perpendicular to the surface, originating at the tips of an indenter impression. The fracture toughness values obtained by the Palmqvist crack model are expressed in the form K{sub C}({pi}/2) > K{sub C} > K{sub C}(0) for the different applied loads and experimental parameters of the boriding process.

  20. 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.

  1. Hot hardness characteristics of ausformed AISI M-50, Matrix 2, WD-65, modified AISI 440-C, and Super Nitralloy

    Science.gov (United States)

    Chevalier, J. L.; Dietrich, M. W.; Zaretsky, E. V.

    1973-01-01

    Short-term hot hardness studies were performed with ausformed AISI M-50, Matrix 2, WD-65, modified AISI 440-C (14-4-1) and case hardened Super Nitralloy. Hardness levels of each material were measured at elevated temperatures in an electric furnace with a low oxygen environment. Test temperatures ranged from 294 to 877 K. The hot hardness characteristics of the ausformed AISI-M-50, Matrix 2 WD-65, and modified AISI 440-C were the same as those determined for high-speed tool steels. Hot hardness for these steels can be predicted within one point Rockwell C. The hot hardness characteristics of both the case and core of Super Nitralloy were superior to AISI 52100 but inferior to the high-speed tool steels. The short-term Rockwell C hardness at temperature for the Super Nitralloy material between 294 and 769 K can be predicted within one point Rockwell C hardness.

  2. Bubble and foam chemistry

    CERN Document Server

    Pugh, Robert J

    2016-01-01

    This indispensable guide will equip the reader with a thorough understanding of the field of foaming chemistry. Assuming only basic theoretical background knowledge, the book provides a straightforward introduction to the principles and properties of foams and foaming surfactants. It discusses the key ideas that underpin why foaming occurs, how it can be avoided and how different degrees of antifoaming can be achieved, and covers the latest test methods, including laboratory and industrial developed techniques. Detailing a variety of different kinds of foams, from wet detergents and food foams, to polymeric, material and metal foams, it connects theory to real-world applications and recent developments in foam research. Combining academic and industrial viewpoints, this book is the definitive stand-alone resource for researchers, students and industrialists working on foam technology, colloidal systems in the field of chemical engineering, fluid mechanics, physical chemistry, and applied physics.

  3. Foams theory, measurements, and applications

    CERN Document Server

    Khan, Saad A

    1996-01-01

    This volume discusses the physics and physical processes of foam and foaming. It delineates various measurement techniques for characterizing foams and foam properties as well as the chemistry and application of foams. The use of foams in the textile industry, personal care products, enhanced oil recovery, firefighting and mineral floatation are highlighted, and the connection between the microstructure and physical properties of foam are detailed. Coverage includes nonaqueous foams and silicone antifoams, and more.

  4. Mechanical and Microstructural Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel AISI 1060

    Directory of Open Access Journals (Sweden)

    Ates H.

    2014-10-01

    Full Text Available Rotary Friction welding is one of the most popular methods of joining similar and dissimilar materials. It is widely used with metals and thermoplastics in a wide variety of aviation, transport and aerospace industrial component designs. This study investigates the influence of friction and upsetting pressures on the hardness, tensile properties and microstructure of the welds. The experimental results showed that as the friction and upsetting pressures increased, the hardness and tensile strength values increased, as well. The tensile fracture of welded joint occurred in the AISI 1060 side. The friction processed joints were evaluated for their integrity and quality aspects by optical and scanning electron microscopy. For the perfect interfacial bonding, sufficient upsetting and friction pressures are necessary to reach the optimal temperature and severe plastic deformation to bring these materials within the attraction range.

  5. Metallurgical and Mechanical Research on Dissimilar Electron Beam Welding of AISI 316L and AISI 4340

    Directory of Open Access Journals (Sweden)

    A. R. Sufizadeh

    2016-01-01

    Full Text Available Dissimilar electron beam welding of 316L austenitic stainless steel and AISI 4340 low alloy high strength steel has been studied. Studies are focused on effect of beam current on weld geometry, optical and scanning electron microscopy, X-ray diffraction of the weld microstructures, and heat affected zone. The results showed that the increase of beam current led to increasing depths and widths of the welds. The optimum beam current was 2.8 mA which shows full penetration with minimum width. The cooling rates were calculated for optimum sample by measuring secondary dendrite arm space and the results show that high cooling rates lead to austenitic microstructure. Moreover, the metallography result shows the columnar and equiaxed austenitic microstructures in weld zone. A comparison of HAZ widths depicts the wider HAZ in the 316L side. The tensile tests results showed that the optimum sample fractured from base metal in AISI 316L side with the UTS values is much greater than the other samples. Moreover, the fractography study presents the weld cross sections with dimples resembling ductile fracture. The hardness results showed that the increase of the beam current led to the formation of a wide softening zone as HAZ in AISI 4340 side.

  6. Shock wave compression behavior of aluminum foam

    Institute of Scientific and Technical Information of China (English)

    程和法; 黄笑梅; 薛国宪; 韩福生

    2003-01-01

    The shock wave compression behavior of the open cell aluminum foam with relative density of 0. 396 was studied through planar impact experiments. Using polyvinylidene fluoride(PVDF) piezoelectric gauge technique, the stress histories and propagation velocities of shock wave in the aluminum foam were measured and analyzed. The results show that the amplitude of shock wave attenuates rapidly with increasing the propagation distance in the aluminum foam, and an exponential equation of the normalized peak stress vs propagation distance of shock wave is established, the attenuation factor in the equation is 0. 286. Furthermore, the Hugoniot relation, νs = 516.85+ 1.27νp,for the aluminum foam is determined by empirical fit to the experimental Hugoniot data.

  7. Polyurethane-Foam Maskant

    Science.gov (United States)

    Bodemeijer, R.

    1985-01-01

    Brown wax previously used to mask hardware replaced with polyurethane foam in electroplating and electroforming operations. Foam easier to apply and remove than wax and does not contaminate electrolytes.

  8. Thermoforming of foam sheet

    NARCIS (Netherlands)

    Akkerman, Remko; Pronk, Ruud M.

    1997-01-01

    Thermoforming is a widely used process for the manufacture of foam sheet products. Polystyrene foam food trays for instance can be produced by first heating the thermoplastic foam sheet, causing the gas contained to build up pressure and expand, after which a vacuum pressure can be applied to draw t

  9. Foam engineering fundamentals and applications

    CERN Document Server

    2012-01-01

    Containing contributions from leading academic and industrial researchers, this book provides a much needed update of foam science research. The first section of the book presents an accessible summary of the theory and fundamentals of foams. This includes chapters on morphology, drainage, Ostwald ripening, coalescence, rheology, and pneumatic foams. The second section demonstrates how this theory is used in a wide range of industrial applications, including foam fractionation, froth flotation and foam mitigation. It includes chapters on suprafroths, flotation of oil sands, foams in enhancing petroleum recovery, Gas-liquid Mass Transfer in foam, foams in glass manufacturing, fire-fighting foam technology and consumer product foams.

  10. Mathematical Modelling of Nitride Layer Growth of Low Temperature Gas and Plasma Nitriding of AISI 316L

    Directory of Open Access Journals (Sweden)

    Triwiyanto A.

    2014-07-01

    Full Text Available This paper present mathematical model which developed to predict the nitrided layer thickness (case depth of gas nitrided and plasma nitrided austenitic stainless steel according to Fick’s first law for pure iron by adapting and manipulating the Hosseini’s model to fit the diffusion mechanism where nitrided structure formed by nitrided AISI 316L austenitic stainless steel. The mathematical model later tested against various actual gas nitriding and plasma nitriding experimental results with varying nitriding temperature and nitriding duration to see whether the model managed to successfully predict the nitrided layer thickness. This model predicted the coexistence of ε-Fe2-3N and γ΄-Fe4N under the present nitriding process parameters. After the validation process, it is proven that the mathematical model managed to predict the nitrided layer growth of the gas nitrided and plasma nitrided of AISI 316L SS up to high degree of accuracy.

  11. A new foam for support of the physically handicapped.

    Science.gov (United States)

    Koreska, J; Albisser, A M

    1975-02-01

    This article is intended to inform professionals in the fields of rehabilitation medicine and biomedical engineering of some of the more significant properities of Temper Foam, a new foam for support of the physically handicapped. The unique properties of this foam are explained in terms of its microstructure, illustrated by scanning electron micrographs and by mechanical tests using an Instron Materials Testing machine. Fourteen non-ambulatory patients with Duchenne muscular dystrophy are using this foam in custom-fitted contoured support systems. Normally, these children show increasing signs of discomfort and skin breakdown due to their inability to alternate areas of weight bearing and high local pressure such as the ischial tuberosities. In our support systems lined with Temper Foam these problems have completely dissappeared. We find that Temper Foam types T-36, T-38 and -41 are ideally suited for patients weighing up to 35 kg. T-41 may be used for patients weighing up to 70 kg.

  12. Shooting in a foam.

    Science.gov (United States)

    Le Goff, Anne; Quéré, David; Clanet, Christophe

    2014-09-21

    We study the motion of a solid sphere after its fast impact on a bath of liquid foam. We identify two regimes of deceleration. At short times, the velocity is still large and the foam behaves similar to a Newtonian fluid of constant viscosity. Then we measure a velocity threshold below which the sphere starts experiencing the foam's elasticity. We interpret this behavior using a visco-elasto-plastic model for foam rheology. Finally we discuss the possibility of stopping a projectile in the foam, and evaluate the capture efficiency.

  13. Foam process models.

    Energy Technology Data Exchange (ETDEWEB)

    Moffat, Harry K.; Noble, David R.; Baer, Thomas A. (Procter & Gamble Co., West Chester, OH); Adolf, Douglas Brian; Rao, Rekha Ranjana; Mondy, Lisa Ann

    2008-09-01

    In this report, we summarize our work on developing a production level foam processing computational model suitable for predicting the self-expansion of foam in complex geometries. The model is based on a finite element representation of the equations of motion, with the movement of the free surface represented using the level set method, and has been implemented in SIERRA/ARIA. An empirically based time- and temperature-dependent density model is used to encapsulate the complex physics of foam nucleation and growth in a numerically tractable model. The change in density with time is at the heart of the foam self-expansion as it creates the motion of the foam. This continuum-level model uses an homogenized description of foam, which does not include the gas explicitly. Results from the model are compared to temperature-instrumented flow visualization experiments giving the location of the foam front as a function of time for our EFAR model system.

  14. Foam consolidation and drainage.

    Science.gov (United States)

    Jun, S; Pelot, D D; Yarin, A L

    2012-03-27

    A theoretical model of foam as a consolidating continuum is proposed. The general model is applied to foam in a gravity settler. It is predicted that liquid drainage from foam in a gravity settler begins with a slow drainage stage. Next, a stage with faster drainage occurs where the drainage rate doubles compared to the initial stage. The experiments conducted within the framework of this work confirmed the theoretical predictions and allowed measurements of foam characteristics. Foams of three different concentrations of Pantene Pro-V Classic Care Solutions shampoo were studied, as well as the addition of polyethylene oxide (PEO) in one case. The shampoo's main foaming components are sodium lauryl sulfate and sodium laureth sulfate. It is shown to what extent foam drainage is slowed down by using higher shampoo concentrations and how it is further decreased by adding polymer (PEO).

  15. Fretting fatigue in AISI 1015 steel

    Indian Academy of Sciences (India)

    R Gnanamoorthy; R Rosi Reddy

    2002-04-01

    A small osillatory movement between two contacting surfaces is termed as fretting and on many occasions it acts as the crack initiation site leading to catastrophic failure of the overall structure. The occurrence of fretting is observed in many engineering structures such as shaft flanges, gas turbines, steel ropes etc. An experimental facility, which can simulate the fretting fatigue in many engineering applications, is the primary requirement of the research program. A laboratory fretting fatigue test facility capable of varying many influencing parameters of fretting fatigue such as slip amplitutde, frequency, contact pressure, etc is designed and developed. Preliminary investigations on plain and fretting fatigue behaviour of AISI 1015 structural steel are reported in this paper. A strength reduction factor of about 1.30 was obtained due to fretting for the test material under the present experimental conditions. Influence of contact load on fretting was also studied. Increasing fretting contact load decreased the fatigue life in the range investigated. Failure analysis showed typical stage I oblique crack growth followed by stage II straight crack perpedicular to the fretting zone.

  16. Optimization of tensile strength of friction welded AISI 1040 and AISI 304L steels according to statistics analysis (ANOVA)

    Energy Technology Data Exchange (ETDEWEB)

    Kirik, Ihsan [Batman Univ. (Turkey); Ozdemir, Niyazi; Firat, Emrah Hanifi; Caligulu, Ugur [Firat Univ., Elazig (Turkey)

    2013-06-01

    Materials difficult to weld by fusion welding processes can be successfully welded by friction welding. The strength of the friction welded joints is extremely affected by process parameters (rotation speed, friction time, friction pressure, forging time, and forging pressure). In this study, statistical values of tensile strength were investigated in terms of rotation speed, friction time, and friction pressure on the strength behaviours of friction welded AISI 1040 and AISI 304L alloys. Then, the tensile test results were analyzed by analysis of variance (ANOVA) with a confidence level of 95 % to find out whether a statistically significant difference occurs. As a result of this study, the maximum tensile strength is very close, which that of AISI 1040 parent metal of 637 MPa to could be obtained for the joints fabricated under the welding conditions of rotation speed of 1700 rpm, friction pressure of 50 MPa, forging pressure of 100 MPa, friction time of 4 s, and forging time of 2 s. Rotation speed, friction time, and friction pressure on the friction welding of AISI 1040 and AISI 304L alloys were statistically significant regarding tensile strength test values. (orig.)

  17. Anaerobic Digestion Foaming Causes

    OpenAIRE

    Ganidi, Nafsika

    2008-01-01

    Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water utilities due to significant impacts on process efficiency and operational costs. Several foaming causes have been suggested over the past few years by researchers. However, the supporting experimental information is limited and in some cases site specific. The present report aimed to provide a better understanding of the anaerobic di...

  18. The science of foaming.

    Science.gov (United States)

    Drenckhan, Wiebke; Saint-Jalmes, Arnaud

    2015-08-01

    The generation of liquid foams is at the heart of numerous natural, technical or scientific processes. Even though the subject of foam generation has a long-standing history, many recent progresses have been made in an attempt to elucidate the fundamental processes at play. We review the subject by providing an overview of the relevant key mechanisms of bubble generation within a coherent hydrodynamic context; and we discuss different foaming techniques which exploit these mechanisms.

  19. Fire-retardant foams

    Science.gov (United States)

    Gagliani, J.

    1978-01-01

    Family of polyimide resins are being developed as foams with exceptional fire-retardant properties. Foams are potentially useful for seat cushions in aircraft and ground vehicles and for applications such as home furnishings and building-construction materials. Basic formulations can be modified with reinforcing fibers or fillers to produce celular materials for variety of applications. By selecting reactants, polymer structure can be modified to give foams with properties ranging from high resiliency and flexibility to brittleness and rigidity.

  20. Shape memory polymer foams

    Science.gov (United States)

    Santo, Loredana

    2016-02-01

    Recent advances in shape memory polymer (SMP) foam research are reviewed. The SMPs belong to a new class of smart polymers which can have interesting applications in microelectromechanical systems, actuators and biomedical devices. They can respond to specific external stimulus changing their configuration and then remember the original shape. In the form of foams, the shape memory behaviour can be enhanced because they generally have higher compressibility. Considering also the low weight, and recovery force, the SMP foams are expected to have great potential applications primarily in aerospace. This review highlights the recent progress in characterization, evaluation, and proposed applications of SMP foams mainly for aerospace applications.

  1. Operator Spin Foam Models

    CERN Document Server

    Bahr, Benjamin; Kamiński, Wojciech; Kisielowski, Marcin; Lewandowski, Jerzy

    2010-01-01

    The goal of this paper is to introduce a systematic approach to spin foams. We define operator spin foams, that is foams labelled by group representations and operators, as the main tool. An equivalence relation we impose in the set of the operator spin foams allows to split the faces and the edges of the foams. The consistency with that relation requires introduction of the (familiar for the BF theory) face amplitude. The operator spin foam models are defined quite generally. Imposing a maximal symmetry leads to a family we call natural operator spin foam models. This symmetry, combined with demanding consistency with splitting the edges, determines a complete characterization of a general natural model. It can be obtained by applying arbitrary (quantum) constraints on an arbitrary BF spin foam model. In particular, imposing suitable constraints on Spin(4) BF spin foam model is exactly the way we tend to view 4d quantum gravity, starting with the BC model and continuing with the EPRL or FK models. That makes...

  2. Breakdown and Evolution of the Protective Oxide Scales of AISI 304 and AISI 316 Stainless Steels under High-Temperature Oxidation

    Directory of Open Access Journals (Sweden)

    K. A. Habib

    2011-01-01

    Full Text Available The failure of the protective oxide scales of AISI 304 and AISI 316 stainless steels has been studied and compared at 1,000°C in synthetic air. First, the isothermal thermogravimetric curves of both stainless steels were plotted to determine the time needed to reach the breakdown point. The different resistance of each stainless steel was interpreted on the basis of the nature of the crystalline phases formed, the morphology, and the surface structure as well as the cross-section structure of the oxidation products. The weight gain of AISI 304 stainless steel was about 8 times greater than that of AISI 316 stainless steel, and AISI 316 stainless steel reached the breakdown point about 40 times more slowly than AISI 304 stainless steel. In both stainless steels, reaching the breakdown point meant the loss of the protective oxide scale of Cr2O3, but whereas in AISI 304 stainless steel the Cr2O3 scale totally disappeared and exclusively Fe2O3 was formed, in AISI 316 stainless steel some Cr2O3 persisted and Fe3O4 was mainly formed, which means that AISI 316 stainless steel is more resistant to oxidation after the breakdown.

  3. The study on the properties of AISI 4140 and AISI 1040 steel rods welded by friction welding

    OpenAIRE

    Thanee Toomprasen; Chawalit Thinvongpituk; Sukangkana Talangkun

    2014-01-01

    This paper is aimed to investigate the properties of joint between AISI 4140 and AISI 1040 welded by friction welding. The specimens were prepared in round shape of 13 mm diameter and 100 mm long. They were welded by friction welding method under the following conditions; friction pressure of 183 MPa, friction time of 12 sec, upset pressure of 428 MPa, upset time of 7 sec. and rotational speed of 1400 rpm. The strength and hardness were tested on the welded area. The result showed finer grain...

  4. 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...

  5. Thermomechanical behaviour of AISI 304 steels; Comportamiento termomecanico de aceros AISI 304

    Energy Technology Data Exchange (ETDEWEB)

    El Wahabi, M.; Garcia, V. G.; Cabrera, J. M.; Prado, J. M.

    2001-07-01

    The hot deformation behaviour of three AISI 304 (H, L and HP) austenitic stainless steel with different carbon contents has been studied. An analysis of the parameters describing their hot flow curves was carried out. No heavy effect of the carbon content was found on most of the latter parameters. However, the work hardening and dynamic recovery behaviour showed clear differences depending on the given alloy, especially at high temperatures and low strain rates where the high carbon steel displayed larger work hardening and dynamic recovery rates than the other steels. The high purity steel (interstitial free) displayed the lower stress levels as its hardening rate was slower than in the other two steels. (Author) 16 refs.

  6. Beer foam physics

    NARCIS (Netherlands)

    Ronteltap, A.D.

    1989-01-01

    The physical aspects of beer foam behavior were studied in terms of the four physical processes, mainly involved in the formation and breakdown of foam. These processes are, bubble formation, drainage, disproportionation and coalescence. In detail, the processes disproportionation and

  7. Beer foam physics.

    NARCIS (Netherlands)

    Ronteltap, L.

    1989-01-01

    The physical aspects of beer foam behavior were studied in terms of the four physical processes, mainly involved in the formation and breakdown of foam. These processes are, bubble formation, drainage, disproportionation and coalescence. In detail, the processes disproportionation and coalescence we

  8. Chronicles of foam films.

    Science.gov (United States)

    Gochev, G; Platikanov, D; Miller, R

    2016-07-01

    The history of the scientific research on foam films, traditionally known as soap films, dates back to as early as the late 17th century when Boyle and Hooke paid special attention to the colours of soap bubbles. Their inspiration was transferred to Newton, who began systematic study of the science of foam films. Over the next centuries, a number of scientists dealt with the open questions of the drainage, stability and thickness of foam films. The significant contributions of Plateau and Gibbs in the middle/late 19th century are particularly recognized. After the "colours" method of Newton, Reinold and Rücker as well as Johhonnot developed optical methods for measuring the thickness of the thinner "non-colour" films (first order black) that are still in use today. At the beginning of the 20th century, various aspects of the foam film science were elucidated by the works of Dewar and Perrin and later by Mysels. Undoubtedly, the introduction of the disjoining pressure by Derjaguin and the manifestation of the DLVO theory in describing the film stability are considered as milestones in the theoretical development of foam films. The study of foam films gained momentum with the introduction of the microscopic foam film methodology by Scheludko and Exerowa, which is widely used today. This historical perspective serves as a guide through the chronological development of knowledge on foam films achieved over several centuries.

  9. Metal foams: A survey

    Institute of Scientific and Technical Information of China (English)

    Michael; F.; Ashby; LU; Tianjian(卢天健)

    2003-01-01

    The current state-of-the-art in the development of cellular metal foams is reviewed, with focus on their fabrication, mechanical/thermal/acoustic properties, and potential applications as lightweight panels, energy absorbers, heat exchangers, and acoustic liners. Foam property charts with scaling relations are presented, allowing scoping and selection through the use of material indices.

  10. Modeling decomposition of rigid polyurethane foam

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, M.L.

    1998-01-01

    Rigid polyurethane foams are used as encapsulants to isolate and support thermally sensitive components within weapon systems. When exposed to abnormal thermal environments, such as fire, the polyurethane foam decomposes to form products having a wide distribution of molecular weights and can dominate the overall thermal response of the system. Decomposing foams have either been ignored by assuming the foam is not present, or have been empirically modeled by changing physical properties, such as thermal conductivity or emissivity, based on a prescribed decomposition temperature. The hypothesis addressed in the current work is that improved predictions of polyurethane foam degradation can be realized by using a more fundamental decomposition model based on chemical structure and vapor-liquid equilibrium, rather than merely fitting the data by changing physical properties at a prescribed decomposition temperature. The polyurethane decomposition model is founded on bond breaking of the primary polymer and formation of a secondary polymer which subsequently decomposes at high temperature. The bond breaking scheme is resolved using percolation theory to describe evolving polymer fragments. The polymer fragments vaporize according to individual vapor pressures. Kinetic parameters for the model were obtained from Thermal Gravimetric Analysis (TGA) from a single nonisothermal experiment with a heating rate of 20 C/min. Model predictions compare reasonably well with a separate nonisothermal TGA weight loss experiment with a heating rate of 200 C/min.

  11. Toughening of phenolic foam

    Science.gov (United States)

    Shen, Hongbin

    2003-06-01

    Phenolic foam has excellent FST performance with relatively low cost, and thus is an attractive material for many applications. However, it is extremely brittle and fragile, precluding it from load-bearing applications. In order to make it tougher and more viable for structural purposes, an effective approach has been proposed and investigated in this study. Composite phenolic foam with short fiber reinforcements resulted in significant improvement in mechanical performance while retaining FST properties comparable to conventional phenolic foam. For example, composite phenolic foam with aramid fibers exhibited a seven-fold increase in peel resistance together with a five-fold reduction in friability. In shear tests, aramid composite foam endured prolonged loading to high levels of strain, indicating the potential for use in structural applications. On the other hand, glass fiber-reinforced phenolic foam produced substantial improvement in the stiffness and strength relative to the unreinforced counterpart. In particular, the Young's modulus of the glass fiber composite foam was increased by as much as 100% relative to the plain phenolic foam in the foam rise direction. In addition, different mechanical behavior was observed for aramid and glass fiber-reinforced foams. In an attempt to understand the mechanical behavior of composite foam, a novel NDT technique, micro-CT, was used to acquire information on fiber length distribution (FLD) and fiber orientation distribution (FOD). Results from micro-CT measurements were compared with theoretical distribution models, achieving various degrees of agreement. Despite some limitations of current micro-CT technology, the realistic observation and measurement of cellular morphology and fiber distribution within composite foams portend future advances in modeling of reinforced polymer foam. To explain the discrepancy observed in shear stiffness between traditional shear test results and those by the short sandwich beam test, a

  12. Novel foaming agent used in preparation process of aluminum foams

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The performances of a novel foaming agent used in the preparation process of aluminum foams were investigated,and the effects of some factors,such as addition of the foaming agent,foaming temperature on the porosity,and appearance of aluminum foams were also discussed.Experimental results show that the novel foaming agent has a wide decomposition temperature range and a mild decomposed rate; the foaming agent has the ability to enhance the viscosity of aluminum melt,as a result,an extra viscosifier such as Ca or SiCp is unnecessary while using this foaming agent; the bubble-free zone in material decreases and the foaming efficiency increases with the increase of foaming agent; the bubble-free zone disappears and the foaming efficiency is near 100% when the addition of foaming agent is more than 1.4wt% ; the porosity of the aluminum foam increases with the increase of foaming agent when the addition of foaming agent is less than 2.2wt% .

  13. The study on the properties of AISI 4140 and AISI 1040 steel rods welded by friction welding

    Directory of Open Access Journals (Sweden)

    Thanee Toomprasen

    2014-06-01

    Full Text Available This paper is aimed to investigate the properties of joint between AISI 4140 and AISI 1040 welded by friction welding. The specimens were prepared in round shape of 13 mm diameter and 100 mm long. They were welded by friction welding method under the following conditions; friction pressure of 183 MPa, friction time of 12 sec, upset pressure of 428 MPa, upset time of 7 sec. and rotational speed of 1400 rpm. The strength and hardness were tested on the welded area. The result showed finer grains. in the welded area. This is the result of friction pressure and upset pressure in the welding process. In addition, the observation result indicated some changes of Ferrite and Pearlite in welded zone. This phase change resulted in the increment of hardness in AISI 4140 at the contact area and adjacent. In part of AISI 1040, the portion of Pearlite and Ferrite are not significantly changed, therefore the value of hardness is almost constant.

  14. Influence of oil and water media on fretting behaviour of AISI 52100 steel rubbing against AISI 1045 steel

    Institute of Scientific and Technical Information of China (English)

    REN Ping-di; CHEN Guang-xiong; ZHU Min-hao; ZHOU Zhong-rong

    2004-01-01

    A series of fretting test were carried out using a DELTA PLINT testing system to study the influence of hydraulic oil and water on fretting behaviour of AISI 52100 steel rubbing against AISI 1045 steel. The test result shows that media hydraulic oil and water have a distinct influence on fretting behaviour of the tested materials. Medium water can lead to shifting of the partial slip regime in the fretting map from a larger displacement amplitude toward a smaller one and enlargement of the mixed slip regime, in comparison with that in ambient atmosphere. While medium hydraulic oil can result in shifting of the partial slip regime from a smaller displacement amplitude toward a larger one. In the gross slip regime, hydraulic oil and water play a positive role as lubrication media. They can clearly decrease the fretting friction coefficient between AISI 52100 and AISI 1045. The test result also demonstrates that this lubrication effect will get better with increasing displacement amplitude and that hydraulic oil is better than water for lubrication. SEM observation of the wear scars displays that the fretting wear mainly results from abrasive wear and delamination of the fretted materials when using these two kinds of substances as lubrication media.

  15. Technology of foamed propellants

    Energy Technology Data Exchange (ETDEWEB)

    Boehnlein-Mauss, Jutta; Kroeber, Hartmut [Fraunhofer Institut fuer Chemische Technologie ICT, Pfinztal (Germany)

    2009-06-15

    Foamed propellants are based on crystalline explosives bonded in energetic reaction polymers. Due to their porous structures they are distinguished by high burning rates. Energy content and material characteristics can be varied by using different energetic fillers, energetic polymers and porous structures. Foamed charges can be produced easily by the reaction injection moulding process. For the manufacturing of foamed propellants a semi-continuous remote controlled production plant in pilot scale was set up and a modified reaction injection moulding process was applied. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  16. The foaming of lavas

    Science.gov (United States)

    Okeefe, J. A.; Walton, W.

    1976-01-01

    Foaming is of great practical and theoretical significance for volcanic processes on the earth, the moon, and perhaps the meteorite parent bodies. The theory of foams agrees with steelmaking experience to indicate that their presence depends on the existence of solutes in the lavas which reduce the surface tension, and are not saturated. These solutes concentrate at the surface, and are called surfactants. The surfactant responsible for the formation of volcanic ash was not identified; it appears to be related to the oxygen partial pressure above the lava. This fact may explain why lunar and meteoritic melts are not observed to foam. Experimental studies are needed to clarify the process.

  17. Micro flows in foams

    Science.gov (United States)

    Koehler, Stephan; Hilgenfeldt, Sascha; Stone, Howard; Weeks, Eric

    2002-11-01

    Foam drainage, the flow of liquid through foams, has been extensively studied macroscopically, on the scale of many bubbles. We use a confocal microscope to determine the flow-field in a single channel, and find good agreement with a model based upon surface rheology (R. A. Leonard and R. Lemlich, AIChE J. 11, p. 25-29 (1965)). The microscopic measurements show different types of flows depending on the type of surfactant used to stabilize the foam, which has also been observed on the macroscopic level. Surprisingly we find very little mixing in the nodes, the regions where four different channels intersect.

  18. Foaming Behaviour, Structure, and Properties of Polypropylene Nanocomposites Foams

    Directory of Open Access Journals (Sweden)

    M. Antunes

    2010-01-01

    Full Text Available This work presents the preparation and characterization of compression-moulded montmorillonite and carbon nanofibre-polypropylene foams. The influence of these nanofillers on the foaming behaviour was analyzed in terms of the foaming parameters and final cellular structure and morphology of the foams. Both nanofillers induced the formation of a more isometric-like cellular structure in the foams, mainly observed for the MMT-filled nanocomposite foams. Alongside their crystalline characteristics, the nanocomposite foams were also characterized and compared with the unfilled ones regarding their dynamic-mechanical thermal behaviour. The nanocomposite foams showed higher specific storage moduli due to the reinforcement effect of the nanofillers and higher cell density isometric cellular structure. Particularly, the carbon nanofibre foams showed an increasingly higher electrical conductivity with increasing the amount of nanofibres, thus showing promising results as to produce electrically improved lightweight materials for applications such as electrostatic painting.

  19. Foaming in stout beers

    OpenAIRE

    Lee, W. T.; M. G. Devereux

    2011-01-01

    We review the differences between bubble formation in champagne and other carbonated drinks, and stout beers which contain a mixture of dissolved nitrogen and carbon dioxide. The presence of dissolved nitrogen in stout beers gives them a number of properties of interest to connoisseurs and physicists. These remarkable properties come at a price: stout beers do not foam spontaneously and special technology, such as the widgets used in cans, is needed to promote foaming. Nevertheless the same m...

  20. 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...

  1. Ultralight metal foams

    Science.gov (United States)

    Jiang, Bin; He, Chunnian; Zhao, Naiqin; Nash, Philip; Shi, Chunsheng; Wang, Zejun

    2015-09-01

    Ultralight (acoustic, vibration, or shock energy damping. However, most of these ultralight materials, especially ultralight metal foams, are fabricated using either expensive materials or complicated procedures, which greatly limit their large-scale production and practical applications. Here we report a simple and versatile method to obtain ultralight monolithic metal foams. These materials are fabricated with a low-cost polymeric template and the method is based on the traditional silver mirror reaction and electroless plating. We have produced ultralight monolithic metal foams, such as silver, nickel, cobalt, and copper via this method. The resultant ultralight monolithic metal foams have remarkably low densities down to 7.4 mg/cm3 or 99.9% porosity. The metal foams have a long flat stress-train curve in compression tests and the densification strain ɛD of the Ni/Ag foam with a porosity of 99.8% can reach 82%. The plateau stress σpl was measured and found to be in agreement with the value predicted by the cellular solids theory.

  2. Weldability of AISI 304 to copper by friction welding

    Energy Technology Data Exchange (ETDEWEB)

    Kirik, Ihsan [Batman Univ. (Turkey); Balalan, Zulkuf [Firat Univ., Elazig (Turkey)

    2013-06-01

    Friction welding is a solid-state welding method, which can join different materials smoothly and is excessively used in manufacturing industry. Friction welding method is commonly used in welding applications of especially cylindrical components, pipes and materials with different properties, for which other welding methods remain incapable. AISI 304 stainless steel and a copper alloy of 99.6 % purity were used in this study. This couple was welded in the friction welding machine. After the welding process, samples were analyzed macroscopically and microscopically, and their microhardness was measured. Tensile test was used to determine the bond strength of materials that were joined using the friction welding method. At the end of the study, it was observed that AISI 304 stainless steel and copper could be welded smoothly using the friction welding method and the bond strength is close to the tensile strength of copper. (orig.)

  3. Laser Welding Of Thin Sheet Of AISI 301 Stainless Steel

    Science.gov (United States)

    Vilar, R.; Miranda, R. M.

    1989-01-01

    Preliminary results of an investigation on laser welding of AISI 301 stainless steel thin sheet are presented. Welds were made with a CO2 continuous wave laser, varying power density and welding speed. The welds were studied by optical and electron scanning microscopy, X-ray diffraction and hardness tests. Experimental results show that under appropriate conditions, sound welds are obtained, with a negligeable heat affected zoneanda fine microstructure in the fusion zone. The fusion zone shows a cellular - dendritic microstructure, with austenite and ferrite as the major constituents. Ferrite, whose content is 5 to 7%, is predominantly intradendritic with both vermicular and acicular morphologies. However some interdendritic ferrite may also be present. The characteristics of the structure suggest that the solidification mode of AISI 301 stainless steel is essentially ferritic.

  4. Tribological and corrosion behaviors of carburized AISI 4340 steel

    Science.gov (United States)

    Thong-on, Atcharawadi; Boonruang, Chatdanai

    2016-01-01

    AISI 4340 steel is widely used in automotive and aircraft industries as gear components. In such applications, surface hardening processes such as carburizing are required in order to improve the life time of the components. There are many studies showing the tribological behavior of the carburized steel, but the corrosion behavior has not yet been clarified. This paper reports on both tribological and corrosion behaviors of the carburized AISI 4340 steel. Factor associated with carburizing, such as the quantities of deposited carbon, dissolved carbon, and formed Cr23C6 and Fe3C, affect the tribological and corrosion behaviors of the steel by improving hardness, friction, lubrication, and wear resistance; but corrosion resistance is reduced. The dissolved carbon affects the formation of the oxide layer of the carburized steel, by obstructing the continuous oxide layer formation and by decreasing the chromium content of the steel, leading to the decrease in the corrosion resistance of the steel.

  5. Magnetic Barkhausen emission in lightly deformed AISI 1070 steel

    Energy Technology Data Exchange (ETDEWEB)

    Capo Sanchez, J., E-mail: jcapo@cnt.uo.edu.cu [Departamento de Fisica, Facultad de Ciencias Naturales, Universidad de Oriente, Av. Patricio Lumumba s/n, 90500 Santiago de Cuba (Cuba); Campos, M.F. de [EEIMVR-Universidade Federal Fluminense, Av. dos Trabalhadores 420, Vila Santa Cecilia, 27255-125 Volta Redonda, RJ (Brazil); Padovese, L.R. [Departamento de Engenharia Mecanica, Escola Politecnica, Universidade de Sao Paulo, Av. Prof. Mello Moraes, 2231, 05508-900 Sao Paulo (Brazil)

    2012-01-15

    The Magnetic Barkhausen Noise (MBN) technique can evaluate both micro- and macro-residual stresses, and provides indication about the relevance of contribution of these different stress components. MBN measurements were performed in AISI 1070 steel sheet samples, where different strains were applied. The Barkhausen emission is also analyzed when two different sheets, deformed and non-deformed, are evaluated together. This study is useful to understand the effect of a deformed region near the surface on MBN. The low permeability of the deformed region affects MBN, and if the deformed region is below the surface the magnetic Barkhausen signal increases. - Highlights: > Evaluated residual stresses by the magnetic Barkhausen technique. > Indication about the relevance of micro-and macro-stress components. > Magnetic Barkhausen measurements were carried out in AISI 1070 steel sheet samples. > Two different sheets, deformed and non-deformed, are evaluated together. > Magnetic Barkhausen signal increases when deformed region is below the surface.

  6. Laser surface hardening of AISI H13 tool steel

    Institute of Scientific and Technical Information of China (English)

    Jae-Ho LEE; Jeong-Hwan JANG; Byeong-Don JOO; Young-Myung SON; Young-Hoon MOON

    2009-01-01

    An attempt was made to improve the surface hardness and wear properties of AISI H13 tool steel through solid solution hardening and refinement of microstructures using a 200 W fiber laser as a heat generating source. The hardness of laser melted zone was investigated. In order to identify the effect of heat input on the laser melting zone, scanning conditions were controlled. The results show that, the hardness of as-received AISI H13 tool steel is approximately Hv 240, and the hardness after laser surface heat treatment is around Hv 480-510. The hardening depth and width are increased with the increase in the heat input applied. Application of experimental results will be considered in tooling industry.

  7. Cutting Forces Analysis in Additive Manufactured AISI H13 Alloy

    OpenAIRE

    Montevecchi, Filippo; Grossi, Niccolò; Takagi, Hisataka; Scippa, Antonio; Sasahara, Hiroyuki; Campatelli, Gianni

    2016-01-01

    Combining Additive Manufacturing (AM) and traditional machining processes is essential to meet components functional requirements. However significant differences arise in machining AM and wrought parts. Previous works highlighted the increasing of tool wear and worse surface finish. In this paper cutting forces are investigated as an indicator of material machinability. Milling cutting force coefficients are identified using mechanistic approach, comparing AISI-H13 wrought and AM specimen. C...

  8. The aluminizing in powder technology of AISI 304 steel

    Science.gov (United States)

    Băitanu, D. B.; Găluşcă, D. G.; Achiţei, D. C.; Minciună, M. G.; Bakri Abdullah, Mohd Mustafa Al

    2016-06-01

    The paper presents a study about the aluminizing treatments applied to AISI 304 stainless steel, with the purpose to improve the corrosion resistance. The aluminizing is realized in a powder medium, composed by aluminium powder (with 99.95% purity), aluminium oxide Al2O3 and ammonium chloride NH4Cl. The structural characterization was made by scanning electronic microscopy to highlight the structure of layer after aluminizing, at different magnitudes.

  9. Study of surface integrity AISI 4140 as result of hard, dry and high speed machining using CBN

    Science.gov (United States)

    Ginting, B.; Sembiring, R. W.; Manurung, N.

    2017-09-01

    The concept of hard, dry and high speed machining can be combined, to produce high productivity, with lower production costs in manufacturing industry. Hard lathe process can be a solution to reduce production time. In lathe hard alloy steels reported problems relating to the integrity of such surface roughness, residual stress, the white layer and the surface integrity. AISI 4140 material is used for high reliable hydraulic system components. This material includes in cold work tool steel. Consideration election is because this material is able to be hardened up to 55 HRC. In this research, the experimental design using CCD model fit with three factors, each factor is composed of two levels, and six central point, experiments were conducted with 1 replications. The experimental design research using CCD model fit.

  10. An Equation of State for Foamed Divinylbenzene (DVB) Based on Multi-Shock Response

    Science.gov (United States)

    Aslam, Tariq; Schroen, Diana; Gustavsen, Richard; Bartram, Brian

    2013-06-01

    The methodology for making foamed Divinylbenzene (DVB) is described. For a variety of initial densities, foamed DVB is examined through multi-shock compression and release experiments. Results from multi-shock experiments on LANL's 2-stage gas gun will be presented. A simple conservative Lagrangian numerical scheme, utilizing total-variation-diminishing interpolation and an approximate Riemann solver, will be presented as well as the methodology of calibration. It has been previously demonstrated that a single Mie-Gruneisen fitting form can replicate foam multi-shock compression response at a variety of initial densities; such a methodology will be presented for foamed DVB.

  11. Dielectric and Radiative Properties of Sea Foam at Microwave Frequencies: Conceptual Understanding of Foam Emissivity

    OpenAIRE

    Gaiser, Peter W.; Anguelova, Magdalena D.

    2012-01-01

    Foam fraction can be retrieved from space-based microwave radiometric data at frequencies from 1 to 37 GHz. The retrievals require modeling of ocean surface emissivity fully covered with sea foam. To model foam emissivity well, knowledge of foam properties, both mechanical and dielectric, is necessary because these control the radiative processes in foam. We present a physical description of foam dielectric properties obtained from the foam dielectric constant including foam skin depth; foam ...

  12. Aqueous foams and foam films stabilised by surfactants. Gravity-free studies

    Science.gov (United States)

    Langevin, Dominique

    2017-01-01

    There are still many open questions and problems in both fundamental research and practical applications of foams. Despite the fact that foams have been extensively studied, many aspects of foam physics and chemistry still remain unclear. Experiments on foams performed under microgravity allow studying wet foams, such as those obtained early during the foaming process. On Earth, wet foams evolve too quickly due to gravity drainage and only dry foams can be studied. This paper reviews the foam and foam film studies that we have performed in gravity-free conditions. It highlights the importance of surface rheology as well as of confinement effects in foams and foam films behaviour.

  13. Surfactant monitoring by foam generation

    Science.gov (United States)

    Mullen, Ken I.

    1997-01-01

    A device for monitoring the presence or absence of active surfactant or other surface active agents in a solution or flowing stream based on the formation of foam or bubbles is presented. The device detects the formation of foam with a light beam or conductivity measurement. The height or density of the foam can be correlated to the concentration of the active surfactant present.

  14. Foaming in stout beers

    CERN Document Server

    Lee, W T

    2011-01-01

    We review the differences between bubble formation in champagne and other carbonated drinks, and stout beers which contain a mixture of dissolved nitrogen and carbon dioxide. The presence of dissolved nitrogen in stout beers gives them a number of properties of interest to connoisseurs and physicists. These remarkable properties come at a price: stout beers do not foam spontaneously and special technology, such as the widgets used in cans, is needed to promote foaming. Nevertheless the same mechanism, nucleation by gas pockets trapped in cellulose fibres, responsible for foaming in carbonated drinks is active in stout beers, but at an impractically slow rate. This gentle rate of bubble nucleation makes stout beers an excellent model system for the scientific investigation of the nucleation of gas bubbles. The equipment needed is very modest, putting such experiments within reach of undergraduate laboratories. Finally we consider the suggestion that a widget could be constructed by coating the inside of a beer...

  15. Long lasting decontamination foam

    Science.gov (United States)

    Demmer, Ricky L.; Peterman, Dean R.; Tripp, Julia L.; Cooper, David C.; Wright, Karen E.

    2010-12-07

    Compositions and methods for decontaminating surfaces are disclosed. More specifically, compositions and methods for decontamination using a composition capable of generating a long lasting foam are disclosed. Compositions may include a surfactant and gelatin and have a pH of less than about 6. Such compositions may further include affinity-shifting chemicals. Methods may include decontaminating a contaminated surface with a composition or a foam that may include a surfactant and gelatin and have a pH of less than about 6.

  16. 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...

  17. Glow Discharge Plasma Nitriding of AISI 304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    A.QAYYUM; M.A.NAVEED; S.ZEB; G.MURTAZA; M.ZAKAULLAH

    2007-01-01

    Glow discharge plasma nitriding of AISI 304 austenitic stainless steel has been carried out for different processing time under optimum discharge conditions established by spectroscopic analysis.The treated samples were analysed by X-ray diffraction(XRD)to explore the changes induced in the crystallographic structure.The XRD pattern confirmed the formation of an expanded austenite phase(γN)owing to incorporation of nitrogen as an interstitial solid solution in the iron lattice.A Vickers microhardness tester was used to evaluate the surface hardness as a function of indentation depth(μm).The results showed clear evidence of surface changes with substantial increase in surface hardness.

  18. A study of cumulative fatigue damage in AISI 4130 steel

    Science.gov (United States)

    Jeelani, S.; Musial, M.

    1986-01-01

    Experimental data were obtained using AISI 4130 steel under stress ratios of -1 and 0. A study of cumulative fatigue damage using Miner's and Kramer's equations for stress ratios of -1 and 0 for low-high, low-high-mixed, high-low, and high-low-mixed stress sequences has revealed that there is a close agreement between the theoretical and experimental values of fatigue damage and fatigue life. Kramer's equation predicts less conservative and more realistic cumulative fatigue damage than the popularly used Miner's rule does.

  19. Mössbauer studies on an AISI 1137 type steel

    Indian Academy of Sciences (India)

    E Güler; H Akta

    2006-06-01

    An AISI 1137 type medium carbon steel was studied by means of scanning electron microscopy and Mössbauer spectroscopy. This steel in as received state at room temperature was ferritic. Different heat treatments on related steel exhibited different microstructures such as pearlite and bainite. Also magnetism of these product phases was determined as 32.7 T and 32.6 T relatively where ferromagnetism of ferritic phase in as received state was 33.05 T. Mössbauer parameters such as isomer shifts and % volumes were also determined before and after transformations.

  20. Plackett-Burman Analysis of Glass Microballoon Filled Syntactic Foams

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jennie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Zachary [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bello, Mollie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cordes, Nikolaus Lynn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-08-21

    Syntactic foams are an important category of composite materials that have abundant applications in a wide variety of fields. The current study utilized a Plackett-Burman (PB) experimental design to investigate the main effects of six variables on properties of syntactic foams formulated from a silicone elastomer and glass microballoons(MB). Findings from this investigation are meant to identify the most significant variables with respect to foam properties. Eight foam samples were created and tested using thermal, physical and mechanical techniques. The data from these tests was then evaluated using a Plackett-Burman response coefficient calculation (RCC). This calculation was applied to determine the statistical significance of the selected variables by comparison with a dummy variable. The data suggests that thermal properties, such as glass transition temperature and coefficient of thermal expansion, do not rely on any of the studied variables. Physical and mechanical measurements however were found to depend heavily on the matrix composition and the vacuum pressure used during mixing. Some variables were found to have little to no effect on any of the studied properties. Ultimately, this data could be used to formulate a comprehensive catalogue of syntactic foams based on their compositions. This type of database would allow customers in industry to identify which syntactic foam would best fit their application according to one or two properties.

  1. Aluminum coating by fluidized bed chemical vapor deposition on austenitic stainless steels AISI 304 and AISI 316

    Directory of Open Access Journals (Sweden)

    Jose Luddey Marulanda-Arevalo

    2015-01-01

    Full Text Available Los revestimientos de aluminio f ueron depositados sobre aceros inoxidables AISI 304 y AISI 316 en el rango de temperatura de 5 60 a 600 °C por deposición química de vapor en lecho fluidizado(CVD – FBR. Se utilizó un lecho que consistía en 10 % de aluminio en polvo y 90 % de lecho inerte (alúmina, el cual fue fluidizado con Ar y como ga ses activadores se utilizó una mezcla de ácido clorhídrico con hidrógeno (HCl/H 2 . En el recubrimiento si n tratamiento térmico están las siguiente s especies: Al 13 Fe 4 , Fe 2 Al 5 , FeAl 2 y Al 5 FeNi, las cuales están presentes para ambos aceros. Además, el tratamiento térmico provoca la difusa de alu minio hacia el sustrato y la difusa de hierro del sustrato haci a la superficie del recubrimiento, haciendo la trans formación de los compuestos ant eriores a FeAl, Fe 2 Al 5 , FeAl 2 , Al 0.99 Fe 0.99 Ni 0.02 , AlNi y el Fe 2 AlCr. Se realizó la simulación termodinámica con el s oftware Thermo Calc para obt ener información de la posible composición y la cantidad de mat erial depositado, para condiciones seleccionadas. Las muestras recubi ertas y sin recubrir, se expus ieron a 750 ºC en una atmósfera d onde el vapor agua se transporta a las muestras usando un flujo de N 2 de 40 ml/min, más 100 % vapor de agua (H 2 O. Los dos sustratos sin revestir se comportaron de manera diferente, ya que el acero AISI 304 soportó bien el a taque y ganó poco peso (0.49 mg/cm 2 , en comparación con el acero AISI 316 que perdió mucho peso (25.4 mg/cm 2 . Los aceros recubiertos ganaron poco de peso durante las mil horas de exposición (0.26 mg/cm 2 y soportaron muy bien el ataque corrosivo en c omparación con sustratos sin r ecubrimiento.

  2. An overview of polyurethane foams in higher specification foam mattresses.

    Science.gov (United States)

    Soppi, Esa; Lehtiö, Juha; Saarinen, Hannu

    2015-02-01

    Soft polyurethane foams exist in thousands of grades and constitute essential components of hospital mattresses. For pressure ulcer prevention, the ability of foams to control the immersion and envelopment of patients is essential. Higher specification foam mattresses (i.e., foam mattresses that relieve pressure via optimum patient immersion and envelopment while enabling patient position changes) are claimed to be more effective for preventing pressure ulcers than standard mattresses. Foam grade evaluations should include resiliency, density, hardness, indentation force/load deflection, progressive hardness, tensile strength, and elongation along with essential criteria for higher specification foam mattresses. Patient-specific requirements may include optimal control of patient immersion and envelopment. Mattress cover characteristics should include breathability, impermeability to fluids, and fire safety and not affect mattress function. Additional determinations such as hardness are assessed according to the guidelines of the American Society for Testing and Materials and the International Organization for Standardization. At this time, no single foam grade provides an optimal combination of the above key requirements, but the literature suggests a combination of at least 2 foams may create an optimal higher specification foam mattress for pressure ulcer prevention. Future research and the development of product specification accuracy standards are needed to help clinicians make evidence-based decisions about mattress use.

  3. Mg Alloy Foam Fabrication via Melt Foaming Method

    Institute of Scientific and Technical Information of China (English)

    Donghui YANC; Changhwan SEO; Bo-Young HUR

    2008-01-01

    For the first time AZ91 (MgAl9Zn1) and AM60 (MgAl6) Mg alloy foams with homogeneous pore structures were prepared successfully via melt foaming method using CaCO3 as blowing agent. It is revealed that the blowing gas to foam the melt is not CO2 but CO, which comes from liquid-solid reaction between Mg melt. The reaction temperature is more than 100℃ lower than CaCO3 decomposition, which makes Mg alloy melts foam into cellular structure much more easily in the temperature range from 690℃ to 750℃.

  4. Development of nonflammable cellulosic foams

    Science.gov (United States)

    Luttinger, M.

    1972-01-01

    The development of a moldable cellulosic foam for use in Skylab instrument storage cushions is considered. Requirements include density of 10 lb cu ft or less, minimal friability with normal handling, and nonflammability in an atmosphere of 70 percent oxygen and 30 percent nitrogen at 6.2 psia. A study of halogenated foam components was made, including more highly chlorinated binders, halogen-containing additives, and halogenation of the cellulose. The immediate objective was to reduce the density of the foam through reduction in inorganic phosphate without sacrificing flame-retarding properties of the foams. The use of frothing techniques was investigated, with particular emphasis on a urea-formaldehyde foam. Halogen-containing flame retardants were deemphasized in favor of inorganic salts and the preparation of phosphate and sulphate esters of cellulose. Utilization of foam products for civilian applications was also considered.

  5. 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....... Moreover, foaming presents adverse environmental impacts owing to the overflowing of the pre-storage or digester tanks. So far, there has never been thoroughly investigation of foaming problem in manure-based digester, which is the main anaerobic digestion applied in Denmark. The purpose of the present...

  6. A comparison of the thermal resistance of a foam neoprene wetsuit to a wetsuit fabricated from aerogel-syntactic foam hybrid insulation

    Energy Technology Data Exchange (ETDEWEB)

    Bardy, Erik [Department of Mechanical and Aerospace Engineering State University of New York at Buffalo 318 Jarvis Hall, Buffalo, NY 14260-4400 (United States); Mollendorf, Joseph [Department of Mechanical and Aerospace Engineering State University of New York at Buffalo 318 Jarvis Hall, Buffalo, NY 14260-4400 (United States); Pendergast, David [Department of Mechanical and Aerospace Engineering State University of New York at Buffalo 318 Jarvis Hall, Buffalo, NY 14260-4400 (United States)

    2006-09-21

    The purpose of this study was to compare the thermal resistance of a wetsuit fabricated from aerogel-syntactic foam hybrid insulation developed by Bardy et al [1] to a foam neoprene wetsuit. The thermal resistance of the hybrid wetsuit and a foam neoprene wetsuit was measured on a human test subject in water at 0.25 MPa (15.25 msw) of hyperbaric pressure. Measurements showed that although certain body regions of the hybrid wetsuit had a higher thermal resistance than foam neoprene, the overall thermal resistance of the hybrid wetsuit was 41% less than a foam neoprene wetsuit, and 51-88% less than predicted values. This was postulated, based on sample testing in water, to be due, in part, to increased heat flow through the hybrid insulation from water filled surface depressions at higher pressures. Other factors may have included water flow over the skin and the presence of thermal bridges in the insulation. Due to a smooth surface and tighter fit, the measured thermal resistance of the foam neoprene wetsuit was within 2-23% of the values predicted using data from Bardy et al [2]. It was concluded that unless the surface depressions can be eliminated, and alternative methods for a tighter fit achieved, foam neoprene provides more thermal protection.

  7. Shape memory polyurethane foams

    Directory of Open Access Journals (Sweden)

    B. K. Kim

    2012-01-01

    Full Text Available Molded flexible polyurethane (PU foams have been synthesized from polypropylene glycol (PPG with different molecular weights (Mw and functionalities (f, and 2,4/2,6-toluene diisocyanate (TDI-80 with water as blowing agent. It was found that the glassy state properties of the foam mainly depended on the urethane group content while the rubbery state properties on the crosslink density. That is, PPG of low MW and low f (more urethane groups provided superior glass state modulus, strength, density, shape fixity and glass transition temperature (Tg, while that of high Mw and high f (higher crosslink density showed high rubbery modulus and shape recovery. Consequently shape fixity of low Mw PPG decreased from 85 to 72% while shape recovery increased from 52 to 63% as the content of high Mw PPG increased from 0 to 40%.

  8. Foams structure and dynamics

    CERN Document Server

    Cantat, Isabelle; Graner, François; Pitois, Olivier; Höhler, Reinard; Elias, Florence; Saint-Jalmes, Arnaud; Rouyer, Florence

    2013-01-01

    This book is the first to provide a thorough description of all aspects of the physico-chemical properties of foams. It sets out what is known about their structure, their stability, and their rheology. Engineers, researchers and students will find descriptions of all the key concepts, illustrated by numerous applications, as well as experiments and exercises for the reader. A solutions manual for lecturers is available via the publisher's web site.

  9. Causal spin foams

    CERN Document Server

    Immirzi, Giorgio

    2016-01-01

    I discuss how to impose causality on spin-foam models, separating forward and backward propagation, turning a given triangulation to a 'causal set', and giving asymptotically the exponential of the Regge action, not a cosine. I show the equivalence of the prescriptions which have been proposed to achieve this. Essential to the argument is the closure condition for the 4-simplices, all made of space-like tetrahedra.

  10. Polyurethane Foam Roofing.

    Science.gov (United States)

    1987-04-01

    underfilled a second or third application of foam may be required to completely fill the void . If a second or third application or pour is required, pour(s...often creates other problems such as pinholes, voids (or "holidays") and cracking. Occasionally, small areas of marginal coating coverage may be found on...which can be worked down into small voids , crevices and pinholes. Suitable caulk sealants can also be used to make corrections. Such corrective

  11. Laser assisted foaming of aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Kathuria, Y.P. [Laser X Co. Ltd., Aichi (Japan)

    2001-09-01

    Recently aluminum foams have evoked considerable interest as an alternative material owing to their wide range of applications ranging from microelectronics, through automobiles to aerospace industries. The manufacturing techniques and characterization methods for aluminum foams require further development to achieve effective and economical use of this material. In this communication the authors demonstrate the feasibility of unidirectional and localized expansion of the aluminum foam using the Nd-YAG/CO{sub 2} laser and powder metallurgy. (orig.)

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

    Science.gov (United States)

    Fang, Qi

    difference existed in water absorption characteristics between foams made of regular and waxy starches. Empirical models were developed to correlate foam water absorption characteristics with relative humidity and polymer content. The developed models fit the data well with relatively small standard errors and uniformly scattered residual plots. Foams with higher polymer content had better abrasion resistance than did foams with lower polymer content.

  13. PERFORMANCE STUDY ON AISI316 AND AISI410 USING DIFFERENT LAYERED COATED CUTTING TOOLS IN CNC TURNING

    Directory of Open Access Journals (Sweden)

    K. RAJA

    2015-01-01

    Full Text Available Stainless steel (SS is used for many commercial and industrial applications owing to its high resistance to corrosion. It is too hard to machine due to its high strength and high work hardening property. A surface property such as surface roughness (SR is critical to the function-ability of machined components. SS is generally regarded as more difficult to machine material and poor SR is obtained during machining. In this paper an attempt has been made to investigate the SR produced by CNC turning on austenitic stainless steel (AISI316 and martensitic stainless steel (AISI410 by different cases of coated cutting tool used at dry conditions. Multilayered coated with TiCN/Al2O3, multilayered coated with Ti(C, N, B and single layered coated with TiAlN coated cutting tools are used. Experiments were carried out by using Taguchi’s L27 orthogonal array. The effect of cutting parameters on SR is evaluated and optimum cutting conditions for minimizing the SR are determined. Analysis of variance (ANOVA is used for identifying the significant parameters affecting the responses. Confirmation experiments are conducted to validate the results obtained from optimization.

  14. Polyurethane Foams with Pyrimidine Rings

    Directory of Open Access Journals (Sweden)

    Kania Ewelina

    2014-09-01

    Full Text Available Oligoetherols based on pyrimidine ring were obtained upon reaction of barbituric acid with glycidol and alkylene carbonates. These oligoetherols were then used to obtain polyurethane foams in the reaction of oligoetherols with isocyanates and water. The protocol of foam synthesis was optimized by the choice of proper kind of oligoetherol and synthetic composition. The thermal resistance was studied by dynamic and static methods with concomitant monitoring of compressive strength. The polyurethane foams have similar physical properties as the classic ones except their enhanced thermal resistance. They stand long-time heating even at 200°C. Moreover thermal exposition of foams results generally in increase of their compressive strength.

  15. Foaming Glass Using High Pressure Sintering

    DEFF Research Database (Denmark)

    Østergaard, Martin Bonderup; Petersen, Rasmus Rosenlund; König, Jakob

    Foam glass is a high added value product which contributes to waste recycling and energy efficiency through heat insulation. The foaming can be initiated by a chemical or physical process. Chemical foaming with aid of a foaming agent is the dominant industrial process. Physical foaming has two...... microscope above maximum foaming temperature gives a suitable foaming temperature for the remaining samples. We show that the foaming kinetics depend on the type of gas and the pressure. A critical pressure of around 20 MPa is found to give the largest expansion for all gasses. Samples are obtained with 100...

  16. Foam Assisted WAG, Snorre Revisit with New Foam Screening Model

    DEFF Research Database (Denmark)

    Spirov, Pavel; Rudyk, Svetlana Nikolayevna; Khan, Arif

    2012-01-01

    on a complex geological model for quick feasibility studies, either for onward practical pilot or as justification for more detailed technical study. The simulation showed that Foam model is applicable. The mismatch between history and actual GOR in some periods of injection is due to the complexity...... as quick reference for future general foam pilot simulations at field scale....

  17. THIRD-GENERATION FOAM BLOWING AGENTS FOR FOAM INSULATION

    Science.gov (United States)

    The report gives results of a study of third-generation blowing agents for foam insulation. (NOTE: the search for third-generation foam blowing agents has led to the realization that, as the number of potential substitutes increases, new concerns, such as their potential to act a...

  18. Average foam life and foaming intensity of foaming phenomenon originating from decomposition reaction

    Energy Technology Data Exchange (ETDEWEB)

    Wu, K.; Wang, Y.; Liang, Z.; Liu, X.; Yao, K.; Zhao, J. [Beijing Univ. of Science and Technology, Metallurgy School (China)

    2003-06-01

    The average foam life anti {tau} and foam intensity i have been defined. The expression of anti {tau} and i were given through the relationship between the gas quantity of carbonate decomposition and time, which could be determined by the mass and heat balance. anti {tau} means the effective foaming endurance time. i is a dimensionless number and means the intensity of the foaming process. With these two parameters and the supplement formation and rupture coefficients (K and k), the foaming process originating from decomposition reaction in the melt can be described quantitatively. Through the experiment in the laboratory, the foam height has been measured during the foaming process originating from reaction of the carbonate decomposition in Na{sub 2}B{sub 4}O{sub 7} melt. By means of the experimental results and through the self-developed calculation program, the foam behaviour parameters (K, k, anti {tau} and i) for the foaming process could be determined under different conditions, such as variations of crucible diameter, added carbonate quantity, initial slag height and foaming agent radius and so on. In this way the foam behaviour of the different foaming processes originating from reaction of carbonate decomposition in Na{sub 2}B{sub 4}O{sub 7} melt would be analysed quantitatively. It was shown that the crucible diameter has little effect on rupture coefficient k, average foam life anti {tau} and foam intensity i, just like the foam caused by blowing gas. However, formation coefficient K was affected by the crucible diameter quite a lot. With increased carbonate and initial slag height, anti {tau} and i increase too. In addition anti {tau} and i are influenced by the particle size of the carbonate added to the Na{sub 2}B{sub 4}O{sub 7} melt. The larger the particle, the lower anti {tau} and i. With addition of the two different sizes of particles, both of them were getting larger. The composition of the melt has also an influence on the foaming process

  19. FoamVis, A Visualization System for Foam Research: Design and Implementation

    OpenAIRE

    Dan R. Lipsa; Roberts, Richard C; Laramee, Robert S

    2015-01-01

    Liquid foams are used in areas such as mineral separation, oil recovery, food and beverage production, sanitation and fire fighting. To improve the quality of products and the efficiency of processes in these areas, foam scientists wish to understand and control foam behaviour. To this end, foam scientists have used foam simulations to model foam behaviour; however, analysing these simulations presents difficult challenges. We describe the main foam research challenges and present the design ...

  20. Dynamic Property of Aluminum Foam

    Directory of Open Access Journals (Sweden)

    S Irie

    2016-09-01

    Full Text Available Aluminum in the foam of metallic foam is in the early stage of industrialization. It has various beneficial characteristics such as being lightweight, heat resistance, and an electromagnetic radiation shield. Therefore, the use of aluminum foam is expected to reduce the weight of equipment for transportation such as the car, trains, and aircraft. The use as energy absorption material is examined. Moreover aluminum foam can absorb the shock wave, and decrease the shock of the blast. Many researchers have reported about aluminum foam, but only a little information is available for high strain rates (103 s-1 or more. Therefore, the aluminum foam at high strain rates hasn't been not characterized yet. The purpose in this research is to evaluate the behavior of the aluminum form in the high-strain rate. In this paper, the collision test on high strain rate of the aluminum foam is investigated. After experiment, the numerical analysis model will be made. In this experiment, a powder gun was used to generate the high strain rate in aluminum foam. In-situ PVDF gauges were used for measuring pressure and the length of effectiveness that acts on the aluminum foam. The aluminum foam was accelerated to about 400 m/s from deflagration of single component powder and the foam were made to collide with the PVDF gauge. The high strain rate deformation of the aluminum form was measured at two collision speeds. As for the result, pressure was observed to go up rapidly when about 70% was compressed. From this result, it is understood that complete crush of the cell is caused when the relative volume is about 70%. In the next stage, this data will be compared with the numerical analysis.

  1. Plasma nitriding of AISI 304L and AISI 316L stainless steels: effect of time in the formation of S phase and the chromium nitrides; Nitretacao a plasma dos acos inoxidaveis AISI 304L e AISI 316L: efeito do tempo na formacao da fase S e dos nitretos de cromo

    Energy Technology Data Exchange (ETDEWEB)

    Souza, D.A. de; Barbosa, G.C.; Pinto, F.A.M.; Gontijo, L.C. [Instituto Federal de Educacao, Ciencia e Tecnologia do Espirito Santo - IFES, Vitoria, ES (Brazil); Canal, G.P.; Cunha, A.G., E-mail: disouzam@yahoo.com.br [Universidade Federal do Espirito Santo (UFES), Vitoria, ES (Brazil). Dept. de Fisica

    2009-07-01

    Plasma nitriding can improve hardness and wear resistance of austenitic stainless steels without losses in corrosion resistance. This fact relies on a nitrided layer constituted only by S phase, without chromium nitrides precipitation. In this work, the effect of nitriding time on phases formed on nitrided layer was investigated in two austenitic stainless steels: AISI 304L e AISI 316L. The samples were nitrided at 420 deg C, using a mixture of 60 % N{sub 2} and 40% H{sub 2}, during 5, 7 and 9 hours. It was noted that chromium nitrides were formed on samples of AISI 304L, nitrided for 7 e 9 hours, while all nitrided samples of AISI 316L showed only formation of S phase. The nitrided layers were characterized using optical microscope and x-ray diffraction. (author)

  2. Investigation of Machinability Characteristics of AISI 316Ti Stainless Steel

    Directory of Open Access Journals (Sweden)

    Yunus Kayır

    2012-01-01

    Full Text Available In this study, many experiments of machinability were carried out on universal turning lathe. The cutting forces that occur during machining of workpieces were measured. A standard dynamometer was used to measure cutting forces. The Dynamometer were assembled on the lathe efficiently. An apart were designed and machined to assembly the dynamometer. Moreover, AISI 316Ti stainless steel parts were turned by carbide cutting tools coated with TiAlN components. Effects of cutting tools with different radius on cutting forces and surface roughness were investigated by using different cutting parameters. Moreover, machined parts' surface roughness was controlled. The experimental results showed that cutting forces increased with the increasing federate, but the surface roughness decreased with increasing the radius of cutting edge.

  3. COLD ROLLING ORTHODONTIC WIRES OF AUSTENITIC STAINLESS STEEL AISI 304

    Directory of Open Access Journals (Sweden)

    Rodrigo Santos Messner

    2013-03-01

    Full Text Available Austenitic stainless steels wires are widely used in the final stages of orthodontic treatment. The objective of this paper is to study the process of conformation of rectangular wires from round wires commercial austenitic stainless steel AISI 304 by the process of cold rolling. The wire quality is evaluated by means of dimensional analysis, microhardness measurements, tensile strength and fractographic analysis of the wires subjected to tensile tests. Also a study on the application of finite element method to simulate the process, comparing the force and rolling stress obtained in the rolling is done. The simulation results are consistent with those obtained in the actual process and the rolled wires show ductile fracture, tensile strength and dimensional variations appropriate to orthodontic standards. The fracture morphology shows the model cup-cone type besides the high deformation and hardness inherent in the cold rolling process.

  4. The Study of Plasma Nitriding of AISI304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; JI Shi-jun; GAO Yu-zhou; SUN Jun-cai

    2004-01-01

    This paper presents results on the plasma nitriding of AISI 304 stainless steel at different temperatures in NH 3 gas. The working pressure was 100~200 Pa and the discharge voltage was 700~800V. The phase of nitrided layer formed on the surface was confirmed by X-ray diffraction. The hardness of the samples was measured by using a Vickers microhardness tester with the load of 50g. After nitriding at about 400 ℃ for two hours a nitrided layer consisting of single γN phase with thickness of 5μm was obtained. Microhardness measurements showed significant increase in the hardness from 240 HV (for untreated samples) up to 950 HV (for nitrided samples at temperature of 420℃). The phase composition, the thickness, the microstructure and the surface topography of the nitrided layer as well as its properties depend essentially on the process parameters.

  5. Fretting of AISI 9310 and selected fretting resistant surface treatments

    Science.gov (United States)

    Bill, R. C.

    1977-01-01

    Fretting wear experiments were conducted with uncoated AISI 9310 mating surfaces, and with combinations incorporating a selected coating to one of the mating surfaces. Wear measurements and SEM observations indicated that surface fatigue, as made evident by spallation and surface crack formation, is an important mechanism in promoting fretting wear to uncoated 9310. Increasing humidity resulted in accelerated fretting, and a very noticeable difference in nature of the fretting debris. Of the coatings evaluated, aluminum bronze with a polyester additive was most effective at reducing wear and minimizing fretting damage to the mating uncoated surface, by means of a selflubricating film that developed on the fretting surfaces. Chromium plate performed as an effective protective coating, itself resisting fretting and not accelerating damage to the uncoated surface.

  6. Experimental survey on the behaviour of AISI 304 steel sheets subjected to perforation

    OpenAIRE

    2010-01-01

    This paper presents and analyzes the behaviour of AISI 304 steel sheets subjected to perforation under a wide range of impact velocities. The relevance of this steel resides in the potential transformation of austenite into martensite during mechanical loading. This process leads to an increase in strength and ductility of the material. It makes the AISI 304 attractive for many engineering applications, especially for building structural elements responsible for absorbing energy under fast lo...

  7. Texture evolution in thin-sheets on AISI 301 metastable stainless steel under dynamic loading

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.Y. [Posco Steels, Pohan, South Korea (Korea, Republic of); Kozaczek, K. [Oak Ridge National Lab., TN (United States); Kulkarni, S.M. [TRW Vehicle Safety Systems, Mesa, AZ (United States); Bastias, P.C.; Hahn, G.T. [Vanderbilt Univ., Nashville, TN (United States)

    1995-05-08

    The evolution of texture in thin sheets of metastable austenitic stainless steel AISI 301 is affected by external conditions such as loading rate and temperature, by inhomogeneous deformation phenomena such as twinning and shear band formation, and by the concurent strain induced phase transformation of the retained austenitc ({gamma}) into martensite ({alpha}). The present paper describes texture measurements on different gauges of AISI 301 prior and after uniaxial stretching under different conditions.

  8. Comportamiento termomecánico de aceros AISI 304

    Directory of Open Access Journals (Sweden)

    El Wahabi, M.

    2001-04-01

    Full Text Available The hot deformation behaviour of three AISI 304 (H, L and HP austenitic stainless steel with different carbon contents has been studied. An analysis of the parameters describing their hot flow curves was carried out. No heavy effect of the carbon content was found on most of the latter parameters. However, the work hardening and dynamic recovery behaviour showed clear differences depending on the given alloy, especially at high temperatures and low strain rates where the high carbon steel displayed larger work hardening and dynamic recovery rates than the other steels. The high purity steel (interstitial free displayed the lower stress levels as its hardening rate was slower than in the other two steels.

    Se llevó a cabo un estudio del comportamiento termomecánico de tres aceros inoxidables austeníticos tipo AISI 304 (H, L y HP con diferentes contenido en carbono, mediante la determinación de los parámetros que describen las etapas de deformación en caliente. No se notó un fuerte efecto del carbono en dichos parámetros, excepto en los que describen los procesos de endurecimiento y de restauración dinámica que muestran una cierta dependencia con la composición química, especialmente a bajos valores del parámetro de Zener-Hollomon, donde el acero de alto carbono (304H endurece y restaura más rápido que el de bajo carbono (304L, alcanzándose valores de tensión de pico similares en ambos casos. El material de alta pureza (libre de intersticiales toma valores de tensión de pico más bajos que los otros aceros, endureciendo más lentamente y con una velocidad de restauración similar a la del 304H.

  9. Linear friction welding of AISI 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Bhamji, Imran, E-mail: imran.bhamji@postgrad.manchester.ac.uk [Manchester Materials Science Centre, University of Manchester, Grosvenor Street, M1 7HS (United Kingdom); Preuss, Michael [Manchester Materials Science Centre, University of Manchester, Grosvenor Street, M1 7HS (United Kingdom); Threadgill, Philip L. [Formerly with TWI Ltd., Cambridge, UK (now retired) (United Kingdom); Moat, Richard J. [Manchester Materials Science Centre, University of Manchester, Grosvenor Street, M1 7HS (United Kingdom); Addison, Adrian C. [TWI Ltd., Cambridge (United Kingdom); Peel, Matthew J. [University of Bristol, Queens Building, University Walk, Bristol BS8 1TR (United Kingdom)

    2010-12-15

    Research highlights: {yields} Linear friction welding is a feasible process for joining AISI316L. {yields} Most welds had tensile strengths superior to the parent material. {yields} Welding parameters had a significant impact on weld microstructure. {yields} Control of microstructure by controlling welding parameters is a process benefit. - Abstract: Linear friction welding is a solid state joining process established as a niche technology for the joining of aeroengine bladed disks. However, the process is not limited to this application, and therefore the feasibility of joining a common engineering austenitic steel, AISI 316L, has been explored. It was found that mechanically sound linear friction welds could be produced in 316L, with tensile properties in most welds exceeding those of the parent material. The mechanical properties of the welds were also found to be insensitive to relatively large changes in welding parameters. Texture was investigated in one weld using high energy synchrotron X-ray diffraction. Results showed a strong {l_brace}1 1 1{r_brace}< 1 1 2 > type texture at the centre of the weld, which is a typical shear texture in face centre cubic materials. Variations in welding parameters were seen to have a significant impact on the microstructures of welds. This was particularly evident in the variation of the fraction of delta ferrite, in the thermo-mechanically affected zone of the welds, with different process parameters. Analysis of the variation in delta ferrite, with different welding parameters, has produced some interesting insights into heat generation and dissipation during the process. It is hoped that a greater understanding of the process could help to make the parameter optimisation process, when welding 316L as well as other materials, more efficient.

  10. Lost Foam Casting in China

    Institute of Scientific and Technical Information of China (English)

    YE Sheng-ping; WU Zhi-chao

    2006-01-01

    @@ 1. Lost Foam Casting Committee of Foundry Institution of Chinese Mechanical Engineering Society (FICMES) From the beginning of the 1990s, China entered a research and expansion climax in lost foam casting technology realm after the United States, Germany, and Japan etc.

  11. Foaming-electrolyte fuel cell

    Science.gov (United States)

    Nanis, L.; Saunders, A. P.

    1970-01-01

    Foam structure feeds fuel gas solution into electrolyte. Fuel gas reacts at static, three-phase interface between fuel gas, electrolyte, and electrode material. The foam forms an electrical contact between main body of electrolyte and the electrode, and aids in removal of by-products of the chemical reaction.

  12. Austenitic Stainless Steel AISI 316L Corrosion Test Research%奥氏体不锈钢AISI 316L腐蚀试验研究

    Institute of Scientific and Technical Information of China (English)

    王金刚; 刘江涛; 程珊珊

    2014-01-01

    在精对苯二甲酸(PTA)生产中,选取干燥机BM302壳体常用材料奥氏体不锈钢AISI 316L为研究对象,在醋酸环境中,对AISI 316L 受Br-及Cl-作用的电化学极化试验和电化学阻抗试验进行腐蚀性试验研究。试验结果表明,Br-或Cl-浓度的增加都会导致AISI 316L不锈钢腐蚀速率增加、击穿电位降低、腐蚀反应电阻减小,导致其耐腐蚀性能下降,腐蚀加剧。为PTA设备腐蚀的现场监测和设备维护提供参考依据。%In purified terephthalic acid (PTA) production, selected the drying machine BM302 shell commonly use material austenitic stainless steel AISI 316L as the research object. In the acetic acid environment, for corrosive test research of AISI 316L, through Br-and Cl-the role of electrochemical polarization test and electrochemical impedance test. The test results show that Br-or Cl-will lead to the increasing of the concentration of seawater AISI 316L stainless steel corrosion rate increase, breakdown voltage is reduced, and the corrosion reaction resistance decreases, and lead to its corrosion resistance drop, corrosion intensifies. That will provide reference for PTA equipment corrosion field monitoring and equipment maintenance.

  13. Spin foams without spins

    Science.gov (United States)

    Hnybida, Jeff

    2016-10-01

    We formulate the spin foam representation of discrete SU(2) gauge theory as a product of vertex amplitudes each of which is the spin network generating function of the boundary graph dual to the vertex. In doing so the sums over spins have been carried out. The boundary data of each n-valent node is explicitly reduced with respect to the local gauge invariance and has a manifest geometrical interpretation as a framed polyhedron of fixed total area. Ultimately, sums over spins are traded for contour integrals over simple poles and recoupling theory is avoided using generating functions.

  14. Effects of X-rays Radiation on AISI 304 Stainless Steel Weldings with AISI 316L Filler Material: A Study of Resistance and Pitting Corrosion Behavior

    Directory of Open Access Journals (Sweden)

    Francisco Javier Cárcel-Carrasco

    2016-04-01

    Full Text Available This article investigates the effect of low-level ionizing radiation, namely X-rays, on the micro structural characteristics, resistance, and corrosion resistance of TIG-welded joints of AISI 304 austenitic stainless steel made using AISI 316L filler rods. The welds were made in two different environments: natural atmospheric conditions and a closed chamber filled with inert argon gas. The influence of different doses of radiation on the resistance and corrosion characteristics of the welds is analyzed. Welded material from inert Ar gas chamber TIG showed better characteristics and lesser irradiation damage effects.

  15. Corrosion and microstructural analysis data for AISI 316L and AISI 347H stainless steels after exposure to a supercritical water environment.

    Science.gov (United States)

    Ruiz, A; Timke, T; van de Sande, A; Heftrich, T; Novotny, R; Austin, T

    2016-06-01

    This article presents corrosion data and microstructural analysis data of austenitic stainless steels AISI 316L and AISI 347H exposed to supercritical water (25 MPa, 550 °C) with 2000 ppb of dissolved oxygen. The corrosion tests lasted a total of 1200 h but were interrupted at 600 h to allow measurements to be made. The microstructural data have been collected in the grain interior and at grain boundaries of the bulk of the materials and at the superficial oxide layer developed during the corrosion exposure.

  16. Corrosion and microstructural analysis data for AISI 316L and AISI 347H stainless steels after exposure to a supercritical water environment

    Directory of Open Access Journals (Sweden)

    A. Ruiz

    2016-06-01

    Full Text Available This article presents corrosion data and microstructural analysis data of austenitic stainless steels AISI 316L and AISI 347H exposed to supercritical water (25 MPa, 550 °C with 2000 ppb of dissolved oxygen. The corrosion tests lasted a total of 1200 h but were interrupted at 600 h to allow measurements to be made. The microstructural data have been collected in the grain interior and at grain boundaries of the bulk of the materials and at the superficial oxide layer developed during the corrosion exposure.

  17. Physical properties of the AISI 348 L{sup *} austenitic stainless steel; Propriedades fisicas do aco inoxidavel austenitico AISI 348 L{sup *}

    Energy Technology Data Exchange (ETDEWEB)

    Teodoro, Celso Antonio; Lucki, Georgi; Silva, Jose Eduardo Rosa da; Terremoto, Luis Antanio Albiac; Castanheira, Myrthes; Damy, Margaret de Almeida [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: cteodoro@ipen.br

    2005-07-01

    The study of radiation damage in metals and alloys, used as structural materials of nuclear reactors has a strategic meaning in nuclear technology, because it allows the performance evaluation of these materials in working conditions of PWR. For this sake it is necessary to know the detrimental structural changes that occur during fast neutron irradiation. The aim of the present work is to show some strain-stress results of the AISI 348 L{sup *} stainless steel utilized as a structural material of the fuel elements of PWR, in comparison with the AISI 304. (author)

  18. Study of residual stresses generated in machining of AISI 4340 steel; Estudo das tensoes residuais geradas na usinagem de aco AISI 4340

    Energy Technology Data Exchange (ETDEWEB)

    Reis, W.P. dos; Fonseca, M.P. Cindra; Serrao, L.F.; Chuvas, T.C.; Oliveira, L.C., E-mail: mcindra@vm.uff.b [Universidade Federal Fluminense (PGMEC/UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Mecanica

    2010-07-01

    Among the mechanical construction steels, AISI 4340 has good harden ability, while combining high strength with toughness and good fatigue strength, making it excellent for application in the metalworking industry, where it can work at different levels and types of requests. Residual stresses are generated in almost all processes of mechanical manufacturing. In this study, the residual stresses generated in different machining processes and heat treatment hardening of AISI 4340 were analyzed by X-ray diffraction, by the sen{sup 2} {psi} method, using Cr{kappa}{beta} radiation and compared. All samples, except for turned and cut by EDM, presented compressive residual stresses in the surface with various magnitudes. (author)

  19. Dielectric and Radiative Properties of Sea Foam at Microwave Frequencies: Conceptual Understanding of Foam Emissivity

    Directory of Open Access Journals (Sweden)

    Peter W. Gaiser

    2012-04-01

    Full Text Available Foam fraction can be retrieved from space-based microwave radiometric data at frequencies from 1 to 37 GHz. The retrievals require modeling of ocean surface emissivity fully covered with sea foam. To model foam emissivity well, knowledge of foam properties, both mechanical and dielectric, is necessary because these control the radiative processes in foam. We present a physical description of foam dielectric properties obtained from the foam dielectric constant including foam skin depth; foam impedance; wavelength variations in foam thickness, roughness of foam layer interfaces with air and seawater; and foam scattering parameters such as size parameter, and refraction index. Using these, we analyze the scattering, absorption, reflection and transmission in foam and gain insights into why volume scattering in foam is weak; why the main absorption losses are confined to the wet portion of the foam; how the foam impedance matching provides the transmission of electromagnetic radiation in foam and maximizes the absorption; and what is the potential for surface scattering at the foam layers boundaries. We put all these elements together and offer a conceptual understanding for the high, black-body-like emissivity of foam floating on the sea surface. We also consider possible scattering regimes in foam.

  20. Comparative study of pulsed Nd:YAG laser welding of AISI 304 and AISI 316 stainless steels

    Science.gov (United States)

    Kumar, Nikhil; Mukherjee, Manidipto; Bandyopadhyay, Asish

    2017-02-01

    Laser welding is a potentially useful technique for joining two pieces of similar or dissimilar materials with high precision. In the present work, comparative studies on laser welding of similar metal of AISI 304SS and AISI 316SS have been conducted forming butt joints. A robotic control 600 W pulsed Nd:YAG laser source has been used for welding purpose. The effects of laser power, scanning speed and pulse width on the ultimate tensile strength and weld width have been investigated using the empirical models developed by RSM. The results of ANOVA indicate that the developed models predict the responses adequately within the limits of input parameters. 3-D response surface and contour plots have been developed to find out the combined effects of input parameters on responses. Furthermore, microstructural analysis as well as hardness and tensile behavior of the selected weld of 304SS and 316SS have been carried out to understand the metallurgical and mechanical behavior of the weld. The selection criteria are based on the maximum and minimum strength achieved by the respective weld. It has been observed that the current pulsation, base metal composition and variation in heat input have significant influence on controlling the microstructural constituents (i.e. phase fraction, grain size etc.). The result suggests that the low energy input pulsation generally produce fine grain structure and improved mechanical properties than the high energy input pulsation irrespective of base material composition. However, among the base materials, 304SS depict better microstructural and mechanical properties than the 316SS for a given parametric condition. Finally, desirability function analysis has been applied for multi-objective optimization for maximization of ultimate tensile strength and minimization of weld width simultaneously. Confirmatory tests have been conducted at optimum parametric conditions to validate the optimization techniques.

  1. Graphene nanoplatelets-reinforced polyetherimide foams prepared by water vapor-induced phase separation

    Directory of Open Access Journals (Sweden)

    H. Abbasi

    2015-05-01

    Full Text Available The present work considers the preparation of medium-density polyetherimide foams reinforced with variable amounts of graphene nanoplatelets (1–10 wt% by means of water vapor-induced phase separation (WVIPS and their characterization . A homogeneous closed-cell structure with cell sizes around 10 µm was obtained, with foams exhibiting zero crystallinity according to X-ray diffraction (XRD. Thermogravimetric analysis under nitrogen showed a two-step thermal decomposition behaviour for both unfilled and graphene-reinforced foams, with foams containing graphene presenting thermal stability improvements, related to a physical barrier effect promoted by the nanoplatelets. Thermo-mechanical analysis indicated that the specific storage modulus of the nanocomposite foams significantly increased owing to the high stiffness of graphene and finer cellular morphology of the foams. Although foamed nanocomposites displayed no further sign of graphene nanoplatelets exfoliation, the electrical conductivity of these foams was significant even for low graphene contents, with a tunnel-like model fitting well to the evolution of the electrical conductivity with the amount of graphene.

  2. Fitness club

    CERN Multimedia

    Fitness club

    2011-01-01

    General fitness Classes Enrolments are open for general fitness classes at CERN taking place on Monday, Wednesday, and Friday lunchtimes in the Pump Hall (building 216). There are shower facilities for both men and women. It is possible to pay for 1, 2 or 3 classes per week for a minimum of 1 month and up to 6 months. Check out our rates and enrol at: http://cern.ch/club-fitness Hope to see you among us! CERN Fitness Club fitness.club@cern.ch  

  3. Mechanical Characterization of Rigid Polyurethane Foams.

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wei-Yang

    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.

  4. 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.

  5. Calibrating the Abaqus Crushable Foam Material Model using UNM Data

    Energy Technology Data Exchange (ETDEWEB)

    Schembri, Philip E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewis, Matthew W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-02-27

    Triaxial test data from the University of New Mexico and uniaxial test data from W-14 is used to calibrate the Abaqus crushable foam material model to represent the syntactic foam comprised of APO-BMI matrix and carbon microballoons used in the W76. The material model is an elasto-plasticity model in which the yield strength depends on pressure. Both the elastic properties and the yield stress are estimated by fitting a line to the elastic region of each test response. The model parameters are fit to the data (in a non-rigorous way) to provide both a conservative and not-conservative material model. The model is verified to perform as intended by comparing the values of pressure and shear stress at yield, as well as the shear and volumetric stress-strain response, to the test data.

  6. Microstructural characterization of an AISI-SAE 4140 steel without nitridation and nitrided; Caracterizacion microestructural de un acero AISI-SAE 4140 sin nitrurar y nitrurado

    Energy Technology Data Exchange (ETDEWEB)

    Medina F, A.; Naquid G, C. [Gerencia de Ciencia de Materiales, Depto. de Sintesis y Caracterizacion de Materiales, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2000-07-01

    It was micro structurally characterized an AISI-SAE 4140 steel before and after of nitridation through the nitridation process by plasma post-unloading microwaves through Optical microscopy (OM), Scanning electron microscopy (SEM) by means of secondary electrons and retrodispersed, X-ray diffraction (XRD), Energy dispersion spectra (EDS) and mapping of elements. (Author)

  7. Study on tempering behaviour of AISI 410 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Gopa, E-mail: gopa_mjs@igcar.gov.in [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Das, C.R.; Albert, S.K.; Bhaduri, A.K.; Thomas Paul, V. [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Panneerselvam, G. [Chemistry Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Dasgupta, Arup [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India)

    2015-02-15

    Martensitic stainless steels find extensive applications due to their optimum combination of strength, hardness and wear-resistance in tempered condition. However, this class of steels is susceptible to embrittlement during tempering if it is carried out in a specific temperature range resulting in significant reduction in toughness. Embrittlement of as-normalised AISI 410 martensitic stainless steel, subjected to tempering treatment in the temperature range of 673–923 K was studied using Charpy impact tests followed by metallurgical investigations using field emission scanning electron and transmission electron microscopes. Carbides precipitated during tempering were extracted by electrochemical dissolution of the matrix and identified by X-ray diffraction. Studies indicated that temper embrittlement is highest when the steel is tempered at 823 K. Mostly iron rich carbides are present in the steel subjected to tempering at low temperatures of around 723 K, whereas chromium rich carbides (M{sub 23}C{sub 6}) dominate precipitation at high temperature tempering. The range 773–823 K is the transition temperature range for the precipitates, with both Fe{sub 2}C and M{sub 23}C{sub 6} types of carbides coexisting in the material. The nucleation of Fe{sub 2}C within the martensite lath, during low temperature tempering, has a definite role in the embrittlement of this steel. Embrittlement is not observed at high temperature tempering because of precipitation of M{sub 23}C{sub 6} carbides, instead of Fe{sub 2}C, preferentially along the lath and prior austenite boundaries. Segregation of S and P, which is widely reported as one of the causes for temper embrittlement, could not be detected in the material even through Auger electron spectroscopy studies. - Highlights: • Tempering behaviour of AISI 410 steel is studied within 673–923 K temperature range. • Temperature regime of maximum embrittlement is identified as 773–848 K. • Results show that type of

  8. Fitness Club

    CERN Multimedia

    Fitness Club

    2011-01-01

    The CERN Fitness Club is organising Zumba Classes on the first Wednesday of each month, starting 7 September (19.00 – 20.00). What is Zumba®? It’s an exhilarating, effective, easy-to-follow, Latin-inspired, calorie-burning dance fitness-party™ that’s moving millions of people toward joy and health. Above all it’s great fun and an excellent work out. Price: 22 CHF/person Sign-up via the following form: https://espace.cern.ch/club-fitness/Lists/Zumba%20Subscription/NewForm.aspx For more info: fitness.club@cern.ch

  9. Spin Foams Without Spins

    CERN Document Server

    Hnybida, Jeff

    2015-01-01

    We formulate the spin foam representation of discrete SU(2) gauge theory as a product of vertex amplitudes each of which is the spin network generating function of the boundary graph dual to the vertex. Thus the sums over spins have been carried out. We focus on the character expansion of Yang-Mills theory which is an approximate heat kernel regularization of BF theory. The boundary data of each $n$-valent node is an element of the Grassmannian Gr(2,$n$) which carries a coherent representation of U($n$) and a geometrical interpretation as a framed polyhedron of fixed total area. Ultimately, sums over spins are traded for contour integrals over simple poles and recoupling theory is avoided using generating functions.

  10. Composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, S.T.; Pekala, R.W.; Kaschmitter, J.L.

    1997-05-06

    Carbon aerogels used as a binder for granulated materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy. 1 fig.

  11. Composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Steven T. (San Leandro, CA); Pekala, Richard W. (Pleasant Hill, CA); Kaschmitter, James L. (Pleasanton, CA)

    1997-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivty and power to system energy.

  12. 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...

  13. Spin Foams and Canonical Quantization

    CERN Document Server

    Alexandrov, Sergei; Noui, Karim

    2011-01-01

    This review is devoted to the analysis of the mutual consistency of the spin foam and canonical loop quantizations in three and four spacetime dimensions. In the three-dimensional context, where the two approaches are in good agreement, we show how the canonical quantization \\`a la Witten of Riemannian gravity with a positive cosmological constant is related to the Turaev-Viro spin foam model, and how the Ponzano-Regge amplitudes are related to the physical scalar product of Riemannian loop quantum gravity without cosmological constant. In the four-dimensional case, we recall a Lorentz-covariant formulation of loop quantum gravity using projected spin networks, compare it with the new spin foam models, and identify interesting relations and their pitfalls. Finally, we discuss the properties which a spin foam model is expected to possess in order to be consistent with the canonical quantization, and suggest a new model illustrating these results.

  14. Mechanical Property of Foamed Metal

    Institute of Scientific and Technical Information of China (English)

    LIU Pei-sheng; SANG Hai-bo

    2004-01-01

    A comprehensive study on the mechanical behavior of foamed metals was demonstrated. The relationship among their mechanical properties, preparation method, porosity and the structure was briefly studied as well.

  15. 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.

  16. Composite and Nanocomposite Metal Foams

    Directory of Open Access Journals (Sweden)

    Isabel Duarte

    2016-01-01

    Full Text Available Open-cell and closed-cell metal foams have been reinforced with different kinds of micro- and nano-sized reinforcements to enhance their mechanical properties of the metallic matrix. The idea behind this is that the reinforcement will strengthen the matrix of the cell edges and cell walls and provide high strength and stiffness. This manuscript provides an updated overview of the different manufacturing processes of composite and nanocomposite metal foams.

  17. Nitriding Process Characterization of Cold Worked AISI 304 and 316 Austenitic Stainless Steels

    Directory of Open Access Journals (Sweden)

    Waldemar Alfredo Monteiro

    2017-01-01

    Full Text Available The nitriding behavior of austenitic stainless steels (AISI 304 and 316 was studied by different cold work degree (0% (after heat treated, 10%, 20%, 30%, and 40% before nitride processing. The microstructure, layer thickness, hardness, and chemical microcomposition were evaluated employing optical microscopy, Vickers hardness, and scanning electron microscopy techniques (WDS microanalysis. The initial cold work (previous plastic deformations in both AISI 304 and 306 austenitic stainless steels does not show special influence in all applied nitriding kinetics (in layer thicknesses. The nitriding processes have formed two layers, one external layer formed by expanded austenite with high nitrogen content, followed by another thinner layer just below formed by expanded austenite with a high presence of carbon (back diffusion. An enhanced diffusion can be observed on AISI 304 steel comparing with AISI 316 steel (a nitrided layer thicker can be noticed in the AISI 304 steel. The mechanical strength of both steels after nitriding processes reveals significant hardness values, almost 1100 HV, on the nitrided layers.

  18. Wear properties of niobium carbide coatings performed by pack method on AISI 1040 steel

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Ugur [Sakarya University, Technical Education Faculty, Department of Metal Education, 54187 Sakarya (Turkey)]. E-mail: ugursen@sakarya.edu.tr

    2005-07-01

    A series of experiments was performed to evaluate tribological properties of niobium carbide coated AISI 1040 steel. In coating process, thermo-reactive diffusion treatment by pack method was performed at the temperatures of 800, 900 and 1000 deg. C for 1-4 h, respectively. Depending on coating process time and temperature, the thickness of niobium carbide layer formed on substrate ranged from 3.4{+-}0.5 to 12{+-}2 {mu}m. The hardness of niobium carbide layers on the steel sample is 1792 HV. The presence of carbides (e.g. NbC, Nb{sub 2}C) formed on the surface of coated AISI 1040 steel was confirmed by X-ray diffraction analysis. Dry wear tests for uncoated and coated AISI 1040 steel against AISI D2 steel were carried out on pin-on-disk configuration and at sliding speed range of 0.5, 1, 2 and 5 m/s, and under 15 N and 30 N loads. The results showed that the average coefficient of friction for coated and uncoated AISI 1040 steel were 0.3 and 0.5, respectively. The specific wear rates for uncoated and coated steel are 4.47x10{sup -5} mm{sup 3}/N.m to 4.29x10{sup -4} and 4.37x10{sup -7} to 3.55x10{sup -5} mm{sup 3}/N.m.

  19. Stability of metallic foams studied under microgravity

    Energy Technology Data Exchange (ETDEWEB)

    Wuebben, Th [University of Bremen (Germany); Stanzick, H [Fraunhofer-Institute (IFAM), Bremen (Germany); Banhart, J [Hahn-Meitner-Institute Berlin, (Germany); Odenbach, S [University of Bremen (Germany)

    2003-01-15

    Metal foams are prepared by mixing a metal powder and a gas-releasing blowing agent, by densifying the mix to a dense precursor and finally foaming by melting the powder compact. The foaming process of aluminium foams is monitored in situ by x-ray radioscopy. One observes that foam evolution is accompanied by film rupture processes which lead to foam coalescence. In order to elucidate the importance of oxides for foam stability, lead foams were manufactured from lead powders having two different oxide contents. The two foam types were generated on Earth and under weightlessness during parabolic flights. The measurements show that the main function of oxide particles is to prevent coalescence, while their influence on bulk viscosity of the melt is of secondary importance.

  20. Plasma post oxidation of nitrocarburized AISI 4140 steel

    Institute of Scientific and Technical Information of China (English)

    LEE Insup

    2006-01-01

    Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of AISI 4140 steel.Plasma nitrocarburizing was conducted for 3 h at 570 ℃ in the nitrogen, hydrogen and methane atmosphere to produce the ε-Fe2-3(N,C) phase.It was found that the compound layer produced by plasma nitrocarburising was predominantly composed of ε-phase, with a small proportion of γ'-Fe4(N,C) phase.The thickness of the compound layer was about 10 μm and the diffusion layer was about 300 μm in thickness, respectively.Plasma post oxidation was performed on the nitrocarburized samples with various oxygen/hydrogen ratio at a constant temperature of 500 ℃ for 1 h.The very thin magnetite (Fe3O4) layer 1-2 μm in thickness on top of the compound layer was obtained by plasma post oxidation.It was confirmed that the corrosion characteristics of the nitrocarburized compound layer can be further improved by the application of the superficial magnetite layer.

  1. AISI waste oxide recycling program. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Aukrust, E.; Downing, K.B.; Sarma, B.

    1995-08-01

    In March 1995 AISI completed a five-year, $60 million collaborative development program on Direct Steelmaking cost-shared by DOE under the Metals Initiative. This program defined an energy-efficient and environmentally-friendly technology to produce hot metal for steelmaking directly from coal and iron ore pellets without incurring the high capital costs and environmental problems associated with traditional coke oven and blast furnace technology. As it becomes necessary to replace present capacity, this new technology will be favored because of reduced capital costs, higher energy efficiency, and lower operating costs. In April 1994, having failed to move forward with a demonstration plant for direct ironmaking, despite substantial efforts by both Stelco and Geneva Steel, an alternative opportunity was sought to commercialize this new technology without waiting until existing ironmaking capacity needed to be replaced. Recycling and resource recovery of steel plant waste oxides was considered an attractive possibility. This led to approval of a ten-month, $8.3 million joint program with DOE on recycling steel plant waste oxides utilizing this new smelting technology. This highly successful trial program was completed in December 1994. The results of the pilot plant work and a feasibility study for a recycling demonstration plant are presented in this final technical report.

  2. Water Impact of Syntactic Foams

    Directory of Open Access Journals (Sweden)

    Adel Shams

    2017-02-01

    Full Text Available Syntactic foams are particulate composite materials that are extensively integrated in naval and aerospace structures as core materials for sandwich panels. While several studies have demonstrated the potential of syntactic foams as energy absorbing materials in impact tests, our understanding of their response to water impact remains elusive. In this work, we attempt a first characterization of the behavior of a vinyl ester/glass syntactic subject to slamming. High-speed imaging is leveraged to elucidate the physics of water impact of syntactic foam wedges in a free-fall drop tower. From the images, we simultaneously measure the deformation of the wedge and the hydrodynamic loading, thereby clarifying the central role of fluid–structure interaction during water impact. We study two different impact heights and microballoon density to assess the role of impact energy and syntactic foam composition on the slamming response. Our results demonstrate that both these factors have a critical role on the slamming response of syntactic foams. Reducing the density of microballoons might help to reduce the severity of the hydrodynamic loading experienced by the wedge, but this comes at the expense of a larger deformation. Such a larger deformation could ultimately lead to failure for large drop heights. These experimental results offer compelling evidence for the role of hydroelastic coupling in the slamming response of syntactic foams.

  3. Microcellular foams made from gliadin.

    Science.gov (United States)

    Quester, S; Dahesh, M; Strey, R

    2014-01-01

    We have generated closed-cell microcellular foams from gliadin, an abundantly available wheat storage protein. The extraction procedure of gliadin from wheat gluten, which involves only the natural solvents water and ethanol, respectively, is described with emphasis on the precipitation step of gliadin which results in a fine dispersion of mostly spherical, submicron gliadin particles composed of myriad of protein molecules. A dense packing of these particles was hydrated and subjected to an atmosphere of carbon dioxide or nitrogen in a high-pressure cell at 250 bar. Subsequent heating to temperatures close to but still below 100 °C followed by sudden expansion and simultaneous cooling resulted in closed-cell microcellular foam. The spherical gliadin templates along with the resulting foam have been analyzed by scanning electron microscope (SEM) pictures. The size distribution of the primary particles shows diameters peaked around 0.54 μm, and the final foam cell size peaks around 1.2 μm, at a porosity of about 80 %. These are the smallest foam cell sizes ever reported for gliadin. Interestingly, the cell walls of these microcellular foams are remarkably thin with thicknesses in the lower nanometer range, thus nourishing the hope to be able to reach gliadin nanofoam.

  4. Development of Defoamers for Confinenment Foam

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D M; Mitchell, A R

    2005-08-10

    Aqueous foam concentrate (AFC) 380 foam was developed by Sandia National Laboratory as a blast mitigation foam for unexploded ordnance (UXO) and its ''engineered foam structure'' is reported to be able to ''envelop chemical or biological aerosols'' [1]. It is similar to commercial fire-fighting foams, consisting mostly of water with small amounts of two alcohols, an ether and surfactant. It also contains xanthan gum, probably, to strengthen the foam film and delay drainage. The concentrate is normally diluted in a 6:94 ratio with water for foaming applications. The diluted solution is normally foamed with air to an expansion factor of about 100 (density 0.01 g/cc), which is called ''dry'' foam. Higher density foam (0.18 > {rho} > 0.03 g/cc) was discovered which had quite different characteristics from ''dry'' foam and was called ''wet'' foam. Some characterization of these foams has also been carried out, but the major effort described in this document is the evaluation, at the small and medium scale, of chemical, mechanical and thermal approaches to defoaming AFC 380 foam. Several chemical approaches to defoaming were evaluated including oxidation and precipitation of the xanthan, use of commercial oil-emulsion or suspension defoamers, pH modification, and cation exchange with the surfactant. Of these the commercial defoamers were most effective. Two mechanical approaches to defoaming were evaluated: pressure and foam rupture with very fine particles. Pressure and vacuum techniques were considered too difficult for field applications but high surface area silica particles worked very well on dry foam. Finally simple thermal techniques were evaluated. An order-disorder transition occurs in xanthan solutions at about 60 C, which may be responsible for the effectiveness of hot air as a defoamer. During defoaming of 55 gallons of foam with hot air, after about 70% of

  5. Development of drilling foams for geothermal applications

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, W.J.; Remont, L.J.; Rehm, W.A.; Chenevert, M.E.

    1980-01-01

    The use of foam drilling fluids in geothermal applications is addressed. A description of foams - what they are, how they are used, their properties, equipment required to use them, the advantages and disadvantages of foams, etc. - is presented. Geothermal applications are discussed. Results of industry interviews presented indicate significant potential for foams, but also indicate significant technical problems to be solved to achieve this potential. Testing procedures and results of tests on representative foams provide a basis for work to develop high-temperature foams.

  6. Experimental investigation on the rheology of foams

    Energy Technology Data Exchange (ETDEWEB)

    Bonilla, L. F. [Univ. Surcolombiana, Neiva, Huila (Colombia); Shah, S. N. [Oklahoma Univ., Norman, OK (United States)

    2000-07-01

    The rheology of foams was investigated using aqueous and gelled foams and employing a pipe-type viscometer. Surfactant at 0.5 per cent concentration was used as the foaming agent. Results indicated that foam fluid rheology can be adequately characterized by the Herschel-Bulkley model. The experimental data served as the starting point for the development of new empirical correlations to predict foam fluid apparent viscosity. The use of these new correlations is expected to provide more accurate estimates of foam fluid rheological properties. 14 refs., 5 tabs., 14 figs.

  7. MECHANISTIC STUDIES OF IMPROVED FOAM EOR PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    William R. Rossen

    2005-03-16

    The objective of this research is to widen the application of foam to enhanced oil recovery (EOR) by investigating fundamental mechanisms of foams in porous media. This research is to lay the groundwork for more-applied research on foams for improved sweep efficiency in miscible gas, steam and surfactant-based EOR. Task 1 investigates the pore-scale interactions between foam bubbles and polymer molecules. Task 2 examines the mechanisms of gas trapping, and interaction between gas trapping and foam effectiveness. Task 3 investigates mechanisms of foam generation in porous media.

  8. Epoxy Foam Encapsulants: Processing and Dielectric Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Linda Domeier; Marion Hunter

    1999-01-01

    The dielectric performance of epoxy foams was investigated to determine if such materials might provide advantages over more standard polyurethane foams in the encapsulation of electronic assemblies. Comparisons of the dielectric characteristics of epoxy and urethane encapsulant foams found no significant differences between the two resin types and no significant difference between as-molded and machined foams. This study specifically evaluated the formulation and processing of epoxy foams using simple methylhydrosiloxanes as the flowing agent and compared the dielectric performance of those to urethane foams of similar density.

  9. Effective Duration of Gas Nitriding Process on AISI 316L for the Formation of a Desired Thickness of Surface Nitrided Layer

    Directory of Open Access Journals (Sweden)

    Mahmoud Hassan R. S.

    2014-07-01

    Full Text Available High temperature gas nitriding performed on AISI 316L at the temperature of 1200°C. The microstructure of treated AISI 316L samples were observed to identify the formation of the microstructure of nitrided surface layer. The grain size of austenite tends to be enlarged when the nitriding time increases, but the austenite single phase structure is maintained even after the long-time solution nitriding. Using microhardness testing, the hardness values drop to the center of the samples. The increase in surface hardness is due to the high nitrogen concentration at or near the surface. At 245HV, the graph of the effective duration of nitriding process was plotted to achieve the maximum depth of nitrogen diffuse under the surface. Using Sigma Plot software best fit lines of the experimental result found and plotted to find out effective duration of nitriding equation as Y=1.9491(1-0.7947x, where Y is the thickness of nitrided layer below the surface and X is duration of nitriding process. Based on this equation, the duration of gas nitriding process can be estimated to produce desired thickness of nitrided layer.

  10. Corrosion Performance of AISI-309 Exposed to Molten Salts V2O5-Na2SO4 at 700°C Applying EIS and Rp Electrochemical Techniques

    Directory of Open Access Journals (Sweden)

    E. F. Diaz

    2015-01-01

    Full Text Available The corrosion performance of AISI-309 exposed 5 days to molten salts 50 mol% V2O5-50 mol% Na2SO4 at 700°C is reported in this paper. Such evaluation was made using three electrochemical techniques: potentiodynamic polarization curve (PC, electrochemical impedance spectroscopy (EIS, and linear polarization resistance (Rp. From PC, the Tafel slopes, Icorr, and Ecorr were obtained. From Nyquist and Bode plots, it was possible to determine two different stages; the first one showed just one loop, which indicated the initial formation of Cr2O3 layer over the metallic surface; after that, the dissolution of Cr2O3 formed a porous layer, which became part of the corrosion products; at the same time a NiO layer combined with sulfur was forming, which was suggested as the second stage, represented by two capacitive loops. EIS plots were in agreement with the physical characterization made from SEM and EDS analyses. Fitting of EIS experimental data allowed us to propose two electrical circuits, being in concordance with the corrosion stages. Parameters obtained from the simulation of EIS data are also reported. From the results, it was stated that AISI-309 suffered intergranular corrosion due to the presence of sulfur, which diffused to the metallic surface through a porous Cr2O3 layer.

  11. 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).

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

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, F., E-mail: florian.rapp@ict.fraunhofer.de, E-mail: anja.schneider@ict.fraunhofer.de; Schneider, A., E-mail: florian.rapp@ict.fraunhofer.de, E-mail: anja.schneider@ict.fraunhofer.de [Fraunhofer Institute for Chemical Technology ICT (Germany); Elsner, P., E-mail: peter.elsner@ict.fraunhofer.de [Fraunhofer Institute for Chemical Technology ICT, Germany and Karlsruhe Institute of Technology KIT (Germany)

    2014-05-15

    Biopolymers are becoming increasingly important to both industry and consumers. With regard to waste management, CO{sub 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)

  13. Surface fatigue life of CBN and vitreous ground carburized and hardened AISI 9310 spur gears

    Science.gov (United States)

    Townsend, Dennis P.; Patel, P. R.

    1988-01-01

    Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9310 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temeprature of 320 K (116 F), an outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used.

  14. EFFECTS OF COPPER ION IMPLANTATION ON ANTIBACTERIAL ACTIVITY OF AISI420 STAINLESS STEEL

    Institute of Scientific and Technical Information of China (English)

    Z.G. Dan; H.W. Ni; B.F. Xu; J. Xiong; P. Y. Xiong

    2005-01-01

    Antibacterial activity of AISI420 stainless steel (SS) implanted by copper was investigated. Ions extracted from a metal vapor vacuum arc (MEVVA) are sourced with 100keV energy and a dose range from 0.2×1017 to 2.0×1017ions .cm-2. The saturation dose of Cu implantation in AISI420 SS and Cu surface concentration were calculated at the energy of 100keV. The effect of dose on the antibacterial activity was analyzed. Results of antibacterial test show that the saturation dose is the optimum implantation dose for best antibacterial activity, which is above 99% against both Escherichia coli and Staphylococcus aureus. Novel phases such as Fe4Cu3 and Cu9.9Fe0.1 were found in the implanted layer by glancing angle X-ray diffraction (GXRD). The antibacterial activity of AISI420 SS attributes to Cu-contained phase.

  15. Evolution of sensitization in stainless steel AISI 304; Evaluacion del grado de sensibilizacion en el acero ionxidable AISI 304

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, O.; Santos, G.

    2003-07-01

    Austenitic stainless steel, when heat-treated at 550-850 degree centigree became susceptible to intergranular corrosion in acids. this phenomenon, know as sensitization, it is result from the precipitation of chrome carbides in the grain boundary, making these areas less resistant to corrosion. Two different electrochemical reactivation tests are compared with a destructive test and related to the classification of its respective microstructures. It was established a quantitative methodology to evaluate the degree of sensitization in AISI 304and also to compare the correspondence of the results with the data of the automatic and portable EPR device for non-destructive field measurement of the degree of sensitization. The used electrochemical techniques were the EPR (Electrochemical Potentiokinetic Reactivation) or single loop test and the PRP (Pasivation Reactivation Potentiokinetic) or double loop test. The destructive test used was boiling, 120 h ferric sulfate-50% sulfuric acid, according to the standard practices ASTM A-262 practices B. The classifications of etch structures were according to the standard practices ASTM A-262 practices B. (Author)

  16. Research on experiment and calculation of foam bursting device

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This research presents experimental data on mechanical foam bursting device, based on the high speed of air fluid impinging insidethe foam bursting device, foam bubbles disrupted as a consequence of pressures changed very quickly as shear force and their impact forces. Experimental data on foam-bursting capacity have been presented. Designed device can provide effective foam bursting on collapse foam.

  17. Changes in porosity of foamed aluminum during solidification

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to control the porosity of foamed aluminum, the changes in the porosity of foamed aluminum melt in the processes of foaming and solidification, the distribution of the porosity of foamed aluminum, and the relationship between them were studied. The results indicated that the porosity of foamed aluminum coincides well with the foaming time.

  18. Stability analysis of uniform equilibrium foam states for EOR processes

    NARCIS (Netherlands)

    Ashoori, E.; Marchesin, D.; Rossen, W.R.

    2011-01-01

    The use of foam for mobility control is a promising mean to improve sweep efficiency in EOR. Experimental studies discovered that foam exhibits three different states (weak foam, intermediate foam, and strong foam). The intermediate-foam state is found to be unstable in the lab whereas the weak- and

  19. Foaming of mixtures of pure hydrocarbons

    Science.gov (United States)

    Robinson, J. V.; Woods, W. W.

    1950-01-01

    Mixtures of pure liquid hydrocarbons are capable of foaming. Nine hydrocarbons were mixed in pairs, in all possible combinations, and four proportions of each combination. These mixtures were sealed in glass tubes, and the foaming was tested by shaking. Mixtures of aliphatic with other aliphatic hydrocarbons, or of alkyl benzenes with other alkyl benzenes, did not foam. Mixtures of aliphatic hydrocarbons with alkyl benzenes did foam. The proportions of the mixtures greatly affected the foaming, the maximum foaming of 12 of 20 pairs being at the composition 20 percent aliphatic hydrocarbon, 80 percent alkyl benzene. Six seconds was the maximum foam lifetime of any of these mixtures. Aeroshell 120 lubricating oil was fractionated into 52 fractions and a residue by extraction with acetone in a fractionating extractor. The index of refraction, foam lifetime, color, and viscosity of these fractions were measured. Low viscosity and high index fractions were extracted first. The viscosity of the fractions extracted rose and the index decreased as fractionation proceeded. Foam lifetimes and color were lowest in the middle fractions. Significance is attached to the observation that none of the foam lifetimes of the fractions or residue is as high as the foam lifetime of the original Aeroshell, indicating that the foaming is not due to a particular foaming constituent, but rather to the entire mixture.

  20. The influence of structural parameters on the permeability of ceramic foams

    Directory of Open Access Journals (Sweden)

    E. A. Moreira

    2004-01-01

    Full Text Available Ceramic foams are a new structural material, characterized by a high porosity and a large surface area and made of megapores interconnected by filaments. This results in a structure with low resistance to fluid flow, making them appropriate for use as a filter. This work studies the influence of several structural parameters, such as porosity, tortuosity, surface area and pore diameter, in predicting the permeability of ceramic foams. Foams with different pore densities were used as porous media. Permeability was measured utilizing water as the flowing fluid. The results show that the predicted permeability scatters widely with the parameters under study. Pore diameter was the structural parameter that best represented the media. An Ergun-type correlation was fitted to the data and represented very well the permeability of the media in all foams under the experimental conditions studied.

  1. Stabilized aqueous foam systems, concentrate for producing a stabilized aqueous foam and method of producing said foam

    Energy Technology Data Exchange (ETDEWEB)

    Rand, P.B.

    This invention comprises a combination of a water soluble polymer of the polyacrylic acid type, a foam stabilizer of dodecyl alcohol, a surfactant, a solvent and water as a concentrate for use in producing stabilized aqueous foams. In another aspect, the invention comprises a solution of the concentrate with water. In still another aspect the invention includes a method of generating stabilized aqueous foams. The stable foams have utility in security systems.

  2. Fitness Club

    CERN Multimedia

    Fitness Club

    2012-01-01

    Open to All: http://cern.ch/club-fitness  fitness.club@cern.ch Boxing Your supervisor makes your life too tough ! You really need to release the pressure you've been building up ! Come and join the fit-boxers. We train three times a week in Bd 216, classes for beginners and advanced available. Visit our website cern.ch/Boxing General Fitness Escape from your desk with our general fitness classes, to strengthen your heart, muscles and bones, improve you stamina, balance and flexibility, achieve new goals, be more productive and experience a sense of well-being, every Monday, Wednesday and Friday lunchtime, Tuesday mornings before work and Thursday evenings after work – join us for one of our monthly fitness workshops. Nordic Walking Enjoy the great outdoors; Nordic Walking is a great way to get your whole body moving and to significantly improve the condition of your muscles, heart and lungs. It will boost your energy levels no end. Pilates A body-conditioning technique de...

  3. Activated flux tungsten inert gas welding of 8 mm-thick AISI 304 austenitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    刘观辉; 刘美华; 易耀勇; 张宇鹏; 罗子艺; 许磊

    2015-01-01

    AISI 304 stainless steel plates were welded with activated flux tungsten inert gas (A-TIG) method by utilizing self-developed activated flux. It is indicated from the experimental results that for 8 mm-thick AISI 304 stainless steel plate, weld joint of full penetration and one-side welding with good weld appearance can be obtained in a single pass without groove preparation by utilizing A-TIG welding. Moreover, activated flux powders do not cause significant effect on the microstructure of TIG weld and the mechanical properties of A-TIG weld joints are also superior to those of C-TIG (conventional TIG) welding.

  4. FLOW STRESS MODEL FOR HARD MACHINING OF AISI H13 WORK TOOL STEEL

    Institute of Scientific and Technical Information of China (English)

    H. Yan; J. Hua; R. Shivpuri

    2005-01-01

    An approach is presented to characterize the stress response of workpiece in hard machining,accounted for the effect of the initial workpiece hardness, temperature, strain and strain rate on flow stress. AISI H13 work tool steel was chosen to verify this methodology. The proposed flow stress model demonstrates a good agreement with data collected from published experiments.Therefore, the proposed model can be used to predict the corresponding flow stress-strain response of AISI H13 work tool steel with variation of the initial workpiece hardness in hard machining.

  5. Development of Flow Stress of AISI H13 Die Steel in Hard Machining

    Institute of Scientific and Technical Information of China (English)

    YAN Hong; QIAN Guohua; HU Qiang

    2007-01-01

    An approach was presented to characterize the stress response of workpiece in hard machining, accounting for the effect of the initial workpiece hardness in addition to temperature, strain and strain rate on flow stress in this paper. AISI H13 die steel was chosen to verify this methodology. The proposed flow stress model demonstrates a good agreement with experimental data. Therefore, the proposed model can be used to predict the corresponding flow stress-strain response of AISI H13 die steel with variation of the initial workpiece hardness in hard machining.

  6. Deformation induced martensite in AISI 316 stainless steel

    Directory of Open Access Journals (Sweden)

    Solomon, N.

    2010-04-01

    Full Text Available The forming process leads to a considerable differentiation of the strain field within the billet, and finally causes the non-uniform distribution of the total strain, microstrusture and properties of the material over the product cross-section. This paper focus on the influence of stress states on the deformation-induced a’ martensitic transformation in AISI Type 316 austenitic stainless steel. The formation of deformation-induced martensite is related to the austenite (g instability at temperatures close or below room temperature. The structural transformation susceptibility is correlated to the stacking fault energy (SFE, which is a function not only of the chemical composition, but also of the testing temperature. Austenitic stainless steels possess high plasticity and can be easily cold formed. However, during cold processing the hardening phenomena always occurs. Nevertheless, the deformation-induced martensite transformation may enhance the rate of work-hardening and it may or may not be in favour of further material processing. Due to their high corrosion resistance and versatile mechanical properties the austenitic stainless steels are used in pressing of heat exchanger plates. However, this corrosion resistance is influenced by the amount of martensite formed during processing. In order to establish the links between total plastic strain, and martensitic transformation, the experimental tests were followed by numerical simulation.

    El proceso de conformación da a lugar a una considerable diferenciación del campo de tensiones dentro de una barra de extrusión y, finalmente, causa una distribución no uniforme de la tensión total, la microestructura y propiedades del material sobre el corte transversal. En este trabajo se estudia la influencia de los estados de tensión sobre la transformación martensítica inducida por deformación en un acero inoxidable austenítico tipo AISI 316. La formación de martensita inducida por

  7. The dynamics of foams with mobile interfaces

    Science.gov (United States)

    Gratton, Michael B.; Davis, Stephen H.

    2011-11-01

    Using a novel technique for resolving nearly singular integrals, we investigate the dynamics of two-dimensional foams with mobile interfaces and an incompressible, inviscid gas phase by a boundary integral method. For foams with small liquid fractions (CMMI-0826703.

  8. Some aspects of image processing using foams

    Energy Technology Data Exchange (ETDEWEB)

    Tufaile, A., E-mail: tufaile@usp.br; Freire, M.V.; Tufaile, A.P.B.

    2014-08-28

    We have explored some concepts of chaotic dynamics and wave light transport in foams. Using some experiments, we have obtained the main features of light intensity distribution through foams. We are proposing a model for this phenomenon, based on the combination of two processes: a diffusive process and another one derived from chaotic dynamics. We have presented a short outline of the chaotic dynamics involving light scattering in foams. We also have studied the existence of caustics from scattering of light from foams, with typical patterns observed in the light diffraction in transparent films. The nonlinear geometry of the foam structure was explored in order to create optical elements, such as hyperbolic prisms and filters. - Highlights: • We have obtained the light scattering in foams using experiments. • We model the light transport in foams using a chaotic dynamics and a diffusive process. • An optical filter based on foam is proposed.

  9. FoamVis, A Visualization System for Foam Research: Design and Implementation

    Directory of Open Access Journals (Sweden)

    Dan R. Lipsa

    2015-03-01

    Full Text Available Liquid foams are used in areas such as mineral separation, oil recovery, food and beverage production, sanitation and fire fighting. To improve the quality of products and the efficiency of processes in these areas, foam scientists wish to understand and control foam behaviour. To this end, foam scientists have used foam simulations to model foam behaviour; however, analysing these simulations presents difficult challenges. We describe the main foam research challenges and present the design of FoamVis, the only existing visualization, exploration and analysis application created to address them. We describe FoamVis’ main features, together with relevant design and implementation notes. Our goal is to provide a global overview and individual feature implementation details that would allow a visualization scientist to extend the FoamVis system with new algorithms and adapt it to new requirements. The result is a detailed presentation of the software that is not provided in previous visualization research papers.

  10. Carbon foam derived from pitches modified with mineral acids by a low pressure foaming process

    Energy Technology Data Exchange (ETDEWEB)

    Tsyntsarski, B.; Petrova, B.; Budinova, T.; Petrov, N.; Krzesinska, M.; Pusz, S.; Majewska, J.; Tzvetkov, P. [Bulgarian Academy of Science, Sofia (Bulgaria). Inst. of Organic Chemistry

    2010-10-15

    Carbon foams with an anisotropic texture and high mechanical strength were produced using precursors obtained after thermo-oxidation treatment of commercial coal-tar pitch with H{sub 2}SO{sub 4} and HNO{sub 3}. The investigations of the relation between the properties of the precursor and the structure of obtained foam indicate, that the composition and softening point of the pitch precursor significantly affect the foaming process, foam structure and foam mechanical strength. The composition and properties of the modified pitches allow foam formation at relatively low pressure and fast heating rate during the foaming process without a stabilization treatment. The foaming process of pitch-based carbon foams, pretreatment of the precursors, and the properties of resultant foams are discussed in this paper.

  11. THE STRUCTURE CONTROL OF ALUMINUM FOAMS PRODUCED BY POWDER COMPACTED FOAMING PROCESS

    Institute of Scientific and Technical Information of China (English)

    X.H. You; F. Wang; L.C. Wang

    2004-01-01

    A new technique, powder compact foaming process for the production of aluminum foams has been studied in this article. According to this method, the aluminum powder is mixed with a powder foaming agent (TiH2). Subsequent to mixing, the powder blend is hot compacted to obtain a dense semi-finished product. Upon heating to temperatures within the range of the melting point, the foaming agent decomposes to evolve gas and the semi-finished product expands into a porous cellular aluminum. Foaming process is the key in this method. Based on experiments, the foaming characteristics were mainly analyzed and discussed. Experiments show that the aluminum-foam with closed pores and a uniform cell structure of high porosity can be obtained using this method by adjusting the foaming parameters: the content of foaming agent and foaming temperature.

  12. Basics of compounding foam dosage forms.

    Science.gov (United States)

    Allen, Loyd V

    2013-01-01

    The purpose of this article is to provide information on the use of foam dosage forms and pharmacists' ability to extemporaneously compound them. The article provides: (1) a discussion on the rationale and advantages of using foams, (2) a differentiation between the various types and structures of foams, (3) a list of the various types of ingredients and examples of each, and (4) a description of the preparation of pharmaceutical foams.

  13. Anaerobic digestion foaming causes – A review

    OpenAIRE

    Ganidi, Nafsika; Tyrrel, Sean F.; Cartmell, Elise

    2009-01-01

    Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water companies due to significant impacts on process efficiency and operational costs. Several foaming causes have been identified over the past few years by researchers. However, the supporting experimental information is limited and in some cases absent. The present report aims to provide a detailed review of the current anaerobic digestion foaming proble...

  14. Electrical Conductivity of Aluminium Alloy Foams

    Institute of Scientific and Technical Information of China (English)

    凤仪; 郑海务; 朱震刚; 祖方遒

    2002-01-01

    Closed-cell aluminium alloy foams were produced using the powder metallurgical technique. The effect of porosityand cell diameter on the electrical conductivity of foams was investigated and the results were compared with anumber of models. It was found that the percolation theory can be successfully applied to describe the dependenceof the electrical conductivity of aluminium alloy foams on the relative density. The cell diameter has a negligibleeffect on the electrical conductivity of foams.

  15. Effect of Foamed Pattern Density on the Lost Foam Process

    OpenAIRE

    T. Pacyniak

    2007-01-01

    The study examines the effect of the foamed polystyrene pattern density on the process of making castings by the lost foam technique with emphasis put on the analysis of simulation tests. The simulation regarded the effect that pattern density is said to have on the mould cavity filling rate, pressure in the gas gap, and size of this gap. For simulation tests of the full mould process, a mathematical model presented in this study was used. For calculations, the author's own algorithm was appl...

  16. An inexpensive strategy for facilitated recovery of metals and fermentation products by foam fractionation process.

    Science.gov (United States)

    Rangarajan, Vivek; Sen, Ramkrishna

    2013-04-01

    Microbial biosurfactants produce foam during aerobic-fermentation processes. The degree of foaminess and foam stability of the lipopeptide-biosurfactant produced by a marine Bacillus megaterium strain were investigated using simulated biosurfactant solution (SBS), biosurfactant broth without cells (BBWOC) and biosurfactant broth with cells (BBWC) in bubble column experiments. The experimental data for foam collapse were fitted using a first-order foam decay model. The first-order rate constant (k), a measure of foam stability, was maximum (k=0.0003 S(-1)) for BBWOC in the pH range 6-9. However, maximum foam stability (k=0.0006 S(-1)) was restricted to pH 7 for BBWC. Foam-based metal removal studies revealed that the metal removal followed a saturation model. The relative binding capacity of each divalent metal was greatly affected by the presence of other divalent metals. The order of lipopeptide binding capacity of the metals was Fe(2+)>Ca(2+)>Mg(2+), with Fe(2+) significantly influencing the foam stability. In case of Fe(2+), Ca(2+) and Mg(2+), maximum metal recovery of 64.7±4.3%, 52±3.1% and 41.4±3.6% respectively was observed at pH 7. The enrichment (E) of the other media components, including cells, was comparatively insignificant. The results of this study have implications in designing and optimizing biosurfactant or protein recovery in situ by foam fractionation as an inexpensive strategy, and also in facilitated metal recovery from industrial effluents and ores. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. The Experimental Investigation of The Effect of Machining Parameters on Burr Formation in Drilling of AISI D2 and AISI D3 Cold Work Steels

    Directory of Open Access Journals (Sweden)

    Yavuz Kaplan

    2011-06-01

    Full Text Available In this study, the effect of changing processing parameters on the burr formation ats the exit end of hole during the drilling process in milling machines of CNC (Computer Numerical Control was examined. . In experimental studies, cold work tool steels (AISI D2, 20 HRC and AISI D3, 28 HRC were drilling by HSS cutting tools with four different lengths in two different diameters (Ø 8 mm and Ø 10 mm. Three different cutting speeds (5 m/min, 10 m/min, 15 m/min and three different feed rates values (0.04 mm/rev, 0.05 mm/rev, 0.06 mm/rev were used in experiments. According to outcomes of the experiment, it was detected that burr height decreases depending on feed rates increase and burr height increases depending on the number of holes, cutting speed and material hardness.

  18. Foam vessel for cryogenic fluid storage

    Science.gov (United States)

    Spear, Jonathan D [San Francisco, CA

    2011-07-05

    Cryogenic storage and separator vessels made of polyolefin foams are disclosed, as are methods of storing and separating cryogenic fluids and fluid mixtures using these vessels. In one embodiment, the polyolefin foams may be cross-linked, closed-cell polyethylene foams with a density of from about 2 pounds per cubic foot to a density of about 4 pounds per cubic foot.

  19. Recycle Glass in Foam Glass Production

    DEFF Research Database (Denmark)

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

    The foam glass industry turn recycle glass into heat insulating building materials. The foaming process is relative insensitive to impurities in the recycle glass. It is therefore considered to play an important role in future glass recycling. We show and discuss trends of use of recycled glasses...... in foam glass industry and the supply sources and capacity of recycle glass....

  20. Carbon dioxide foaming of glassy polymers

    NARCIS (Netherlands)

    Wessling, M.; Borneman, Z.; Boomgaard, van den Th.; Smolders, C.A.

    1994-01-01

    The mechanism of foaming a glassy polymer using sorbed carbon dioxide is studied in detail. A glassy polymer supersaturated with nitrogen forms a microcellular foam, if the polymer is quickly heated above its glass transition temperature. A glassy polymer supersaturated with CO2 forms this foam-like

  1. Bicontinuous nanoporous polymers by carbon dioxide foaming

    NARCIS (Netherlands)

    Krause, B.; Münüklü, P.; van der Vegt, N.F.A.; Wessling, Matthias; Sijbesma, H.P.

    2001-01-01

    We investigate the physical foaming process of glassy poly(ether imide) and poly(ether sulfone) using carbon dioxide and report temperature-concentration diagrams ("foam diagrams") marking out the foaming envelope in which dense CO2-saturated films expand and microvoids are introduced. Two types of

  2. Structure and properties of the Stainless steel AISI 316 nitrided with microwave plasma; Estructura y propiedades del acero inoxidable AISI 316 nitrurado con plasmas de microondas

    Energy Technology Data Exchange (ETDEWEB)

    Becerril R, F

    1999-07-01

    In this work were presented the results obtained by nitridation on stainless steel AISI 316 using a plasma generated through a microwave discharge with an external magnetic field using several moistures hydrogen / nitrogen to form a plasma. The purpose of nitridation was to increase the surface hardness of stainless steel through a phase formation knew as {gamma}N which has been reported that produces such effect without affect the corrosion resistance proper of this material. (Author)

  3. Various Facets of Spacetime Foam

    CERN Document Server

    Ng, Y Jack

    2011-01-01

    Spacetime foam manifests itself in a variety of ways. It has some attributes of a turbulent fluid. It is the source of the holographic principle. Cosmologically it may play a role in explaining why the energy density has the critical value, why dark energy/matter exists, and why the effective dynamical cosmological constant has the value as observed. Astrophysically the physics of spacetime foam helps to elucidate why the critical acceleration in modified Newtonian dynamics has the observed value; and it provides a possible connection between global physics and local galactic dynamics involving the phenomenon of flat rotation curves of galaxies and the observed Tully-Fisher relation. Spacetime foam physics also sheds light on nonlocal gravitational dynamics.

  4. Fitness cost

    DEFF Research Database (Denmark)

    Nielsen, Karen L.; Pedersen, Thomas M.; Udekwu, Klas I.

    2012-01-01

    of each isolate was determined in a growth competition assay with a reference isolate. Significant fitness costs of 215 were determined for the MRSA isolates studied. There was a significant negative correlation between number of antibiotic resistances and relative fitness. Multiple regression analysis...... to that seen in Denmark. We propose a significant fitness cost of resistance as the main bacteriological explanation for the disappearance of the multiresistant complex 83A MRSA in Denmark following a reduction in antibiotic usage.......Denmark and several other countries experienced the first epidemic of methicillin-resistant Staphylococcus aureus (MRSA) during the period 196575, which was caused by multiresistant isolates of phage complex 83A. In Denmark these MRSA isolates disappeared almost completely, being replaced by other...

  5. Influence of gravity on foams

    Science.gov (United States)

    Monnereau, C.; Vignes-Adler, M.; Kronberg, B.

    1999-06-01

    The feasibility of experiments on the physics of foams in microgravity environment was investigated during a parabolic flight campaign. Transient foams from surfactant-free organic liquids and stable foams from a soapy solution of a Sodium Dodecyl Sulfate + Dodecanol mixture were investigated. In 0g, the transient foam is stabilized; whatever the liquid the foam bubbles are spherical and their diameter does not change during the flight. When the gravity constant is equal to 1.8 g, the bubbles of the stable foam become polyhedral and numerous topological transformations could be observed. La faisabilité d'expériences permettant d'étudier la physique de la mousse en microgravité a été démontrée au cours de vols paraboliques. Nous avons testé des mousses de liquides organiques sans tensioactif qui sont éphémères dans le champ terrestre, et des mousses à base d'une solution aqueuse d'un mélange de Dodécyl Sulfate de Sodium et de Dodécanol qui sont au contraire très stables. En microgravité, les mousses éphémères sont stabilisées; quel que soit le liquide, les bulles sont sphériques et leur diamètre reste égal à leur valeur initiale. Lorsqu'au cours de la parabole, la gravité devient égale à 1,8 g, les bulles de la mousse stable dont les films sont très rigides prennent une forme polyédrique ; de très nombreuses transformations topologiques de type T1 ont pu alors être observées.

  6. Thermal Expansion of Polyurethane Foam

    Science.gov (United States)

    Lerch, Bradley A.; Sullivan, Roy M.

    2006-01-01

    Closed cell foams are often used for thermal insulation. In the case of the Space Shuttle, the External Tank uses several thermal protection systems to maintain the temperature of the cryogenic fuels. A few of these systems are polyurethane, closed cell foams. In an attempt to better understand the foam behavior on the tank, we are in the process of developing and improving thermal-mechanical models for the foams. These models will start at the microstructural level and progress to the overall structural behavior of the foams on the tank. One of the key properties for model characterization and verification is thermal expansion. Since the foam is not a material, but a structure, the modeling of the expansion is complex. It is also exacerbated by the anisoptropy of the material. During the spraying and foaming process, the cells become elongated in the rise direction and this imparts different properties in the rise direction than in the transverse directions. Our approach is to treat the foam as a two part structure consisting of the polymeric cell structure and the gas inside the cells. The polymeric skeleton has a thermal expansion of its own which is derived from the basic polymer chemistry. However, a major contributor to the thermal expansion is the volume change associated with the gas inside of the closed cells. As this gas expands it exerts pressure on the cell walls and changes the shape and size of the cells. The amount that this occurs depends on the elastic and viscoplastic properties of the polymer skeleton. The more compliant the polymeric skeleton, the more influence the gas pressure has on the expansion. An additional influence on the expansion process is that the polymeric skeleton begins to breakdown at elevated temperatures and releases additional gas species into the cell interiors, adding to the gas pressure. The fact that this is such a complex process makes thermal expansion ideal for testing the models. This report focuses on the thermal

  7. Quasicrystalline three-dimensional foams

    Science.gov (United States)

    Cox, S. J.; Graner, F.; Mosseri, R.; Sadoc, J.-F.

    2017-03-01

    We present a numerical study of quasiperiodic foams, in which the bubbles are generated as duals of quasiperiodic Frank–Kasper phases. These foams are investigated as potential candidates to the celebrated Kelvin problem for the partition of three-dimensional space with equal volume bubbles and minimal surface area. Interestingly, one of the computed structures falls close to (but still slightly above) the best known Weaire–Phelan periodic candidate. In addition we find a correlation between the normalized bubble surface area and the root mean squared deviation of the number of faces, giving an additional clue to understanding the main geometrical ingredients driving the Kelvin problem.

  8. Heat exchanger using graphite foam

    Science.gov (United States)

    Campagna, Michael Joseph; Callas, James John

    2012-09-25

    A heat exchanger is disclosed. The heat exchanger may have an inlet configured to receive a first fluid and an outlet configured to discharge the first fluid. The heat exchanger may further have at least one passageway configured to conduct the first fluid from the inlet to the outlet. The at least one passageway may be composed of a graphite foam and a layer of graphite material on the exterior of the graphite foam. The layer of graphite material may form at least a partial barrier between the first fluid and a second fluid external to the at least one passageway.

  9. Is Quantum Spacetime Foam Unstable?

    CERN Document Server

    Redmount, I H; Redmount, Ian H.; Suen, Wai-Mo

    1993-01-01

    A very simple wormhole geometry is considered as a model of a mode of topological fluctutation in Planck-scale spacetime foam. Quantum dynamics of the hole reduces to quantum mechanics of one variable, throat radius, and admits a WKB analysis. The hole is quantum-mechanically unstable: It has no bound states. Wormhole wave functions must eventually leak to large radii. This suggests that stability considerations along these lines may place strong constraints on the nature and even the existence of spacetime foam.

  10. Process for epoxy foam production

    Science.gov (United States)

    Celina, Mathias C [Albuquerque, NM

    2011-08-23

    An epoxy resin mixture with at least one epoxy resin of between approximately 60 wt % and 90 wt %, a maleic anhydride of between approximately 1 wt % and approximately 30 wt %, and an imidazole catalyst of less than approximately 2 wt % where the resin mixture is formed from at least one epoxy resin with a 1-30 wt % maleic anhydride compound and an imidazole catalyst at a temperature sufficient to keep the maleic anhydride compound molten, the resin mixture reacting to form a foaming resin which can then be cured at a temperature greater than 50.degree. C. to form an epoxy foam.

  11. Foam Assisted WAG, Snorre Revisit with New Foam Screening Model

    DEFF Research Database (Denmark)

    Spirov, Pavel; Rudyk, Svetlana Nikolayevna; Khan, Arif

    2012-01-01

    This study deals with simulation model of Foam Assisted Water Alternating Gas (FAWAG) method that had been implemented to two Norwegian Reservoirs. Being studied on number of pilot projects, the method proved successful, but Field Scale simulation was never understood properly. New phenomenologic...

  12. Effects of Plasma Nitriding on the Erosion Behavior of AISI 403 Stainless Steel Solid State Particles

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Ji Won; Park, Hee Jin; Baik, Kyeong Ho [Chungnam National University, Daejeon (Korea, Republic of); Kim, In Soo; Yang, Byung Il [Doosan Heavy Industries and Construction Co., Ltd., Changwon (Korea, Republic of)

    2014-01-15

    This study investigated the effects of plasma nitriding on the erosion behavior of AISI 403 stainless steel solid state particles at ambient temperature and 620 ℃ using Fe{sub 3}O{sub 4} erodent particles at impact angles of 15-90°. The plasma nitriding formed a thick hardened layer which had a high microhardness of 1210 ± 15 Hv. At ambient temperature, AISI 403 suffered from severe erosion damage at low impact angles and exhibited ductile erosive behavior, while the nitrided layer experienced no significant damage at any impact angles. For AISI 403, the erosion rates at 620 ℃ were ⁓2 times higher than those obtained at ambient temperature. When eroded at 620 ℃, the nitrided layer exhibited a ductile erosive manner, with a maximum erosion rate occurring at a low impact angle of 30°. The results from high temperature hardness measurement and the observation of the eroded surface are discussed to explain the high-temperature erosion behavior of the nitrided AISI 403 stainless steel.

  13. Micro-structural strengthening mechanism of multiple laser shock processing impacts on AISI 8620 steel

    Energy Technology Data Exchange (ETDEWEB)

    Lu, J.Z. [School of Mechanical Engineering, Jiangsu University, Xuefu Road 301, Jingkou District, Zhenjiang 212013 (China); Zhong, J.W., E-mail: zjw1033@126.com [School of Mechanical Engineering, Jiangsu University, Xuefu Road 301, Jingkou District, Zhenjiang 212013 (China); Luo, K.Y.; Zhang, L.; Dai, F.Z. [School of Mechanical Engineering, Jiangsu University, Xuefu Road 301, Jingkou District, Zhenjiang 212013 (China); Chen, K.M. [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Wang, Q.W.; Zhong, J.S.; Zhang, Y.K. [School of Mechanical Engineering, Jiangsu University, Xuefu Road 301, Jingkou District, Zhenjiang 212013 (China)

    2011-07-25

    Highlights: {yields} LSP can clearly refine coarse grains in the shocked region by dislocation movement. {yields} Micro-structural evolution of AISI 8620 steel after LSP impacts is revealed. {yields} LSP on AISI 8620 steel have grain refinement and dispersion strengthening of carbon. {yields} The results can provide some insights on surface modification of low carbon steel. - Abstract: Micro-structural evolution in the near-surface region of AISI 8620 steel subjected to multiple laser shock processing (LSP) impacts were investigated by means of cross-sectional optical microscopy (OM) and transmission electron microscopy (TEM) observations. Micro-structural evolution process subjected to multiple LSP impacts can be described as follows: (i) the parallel lamellar pearlites are broken into bitty pearlites, and dislocation activities simultaneously led to the formation of dislocation lines (DLs) and dislocation pile-ups in original grains; (ii) bitty pearlites were all broken into Fe{sub 3}C granules, and dislocation movement made Fe{sub 3}C granules disperse near subgrain boundaries and led to subgrain boundaries separating individual cells, and (iii) subgrain boundaries were refined to grain boundaries. Multiple LSP impacts on AISI 8620 steel had dual-function: the refinement of coarse grains in the near-surface region by dislocation movement and dispersion strengthening of C atoms which cut cementite and diffused into the ferrite by moving dislocations.

  14. Influence of temperature on AISI 316L corrosion in phosphoric acid solutions under hydrodynamic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Tovar, R.; Montanes, M.T.; Garcia-Anton, J. [Valencia Univ. Politecnica, Dept. de Ingenieria Quimica y Nuclear. ETSI Industriales, Valencia (Spain); Ben Bachir, A.; Abdelkebir, B.; Elmandoubi, N. [University Mohammed V-Agdal, Lab. Corrosion-Electrochimie, Faculty of Sciences, Rabat (Morocco)

    2009-07-01

    AISI 316L stainless steel, due to its good mechanical properties and corrosion resistance, is widely used in the phosphoric acid industry, including piping lines. However, phosphoric acid (H{sub 3}PO{sub 4}) is a medium-strong acid, and corrosion problems could occur, especially working with concentrated solutions and increasing temperature. Furthermore, fluid flow can increase corrosion rates. The objective of this work is to study the dynamic corrosion of AISI 316L stainless steel in a range of temperature from 25 C to 60 C by means of cyclic potentiodynamic curves. A hydrodynamic circuit was used in order to study dynamic corrosion. The experiments were carried out in an oxygen-free environment at different Reynolds numbers: 1,456, 3,166 and 5,066. The results show that uniform corrosion mechanisms can be expected for AISI 316L stainless steel in 5.5 M H{sub 3}PO{sub 4} solutions, since no hysteresis loop was observed. Moreover, temperature affects the corrosion parameters obtained from the polarization curves. Temperature shifts corrosion potential to nobler values, reduces the passivity region and enhances passivation current density. On the other hand, little influence of Reynolds number was observed on AISI 316L stainless steel corrosion. (authors)

  15. The adhesion of hot-filament CVD diamond films on AISI type 316 austenitic stainless steel

    NARCIS (Netherlands)

    Buijnsters, J.G.; Shankar, P.; Enckevort, W.J.P. van; Schermer, J.J.; Meulen, J.J. ter

    2004-01-01

    Steel ball indentation and scratch adhesion testing of hot filament chemical vapour deposited diamond films onto AISI type 316 austenitic stainless steel substrates using two different interlayer systems, namely chromium nitride and borided steel, have been investigated. In order to compare the adhe

  16. Surface characterization and wear behaviour of laser surface melted AISI 316L stainless steel

    CSIR Research Space (South Africa)

    Kumar, A

    2010-01-01

    Full Text Available The present study concerns an in depth investigation of the influence of laser surface melting of AISI 316L stainless steel using Ar and N2 as shrouding atmosphere. Laser surface melting has been carried out using a 5 kW continuous wave (CW) fibre...

  17. Fitness Club

    CERN Multimedia

    Fitness Club

    2012-01-01

    Get in Shape for Summer with the CERN Fitness Club Saturday 23 June 2012 from 14:30 to 16.30 (doors open at 14.00) Germana’s Fitness Workshop. Build strength and stamina, sculpt and tone your body and get your heart pumping with Germana’s workout mixture of Cardio Attack, Power Pump, Power Step, Cardio Combat and Cross-Training. Where: 216 (Pump room – equipped with changing rooms and showers). What to wear: comfortable clothes and indoor sports shoes + bring a drink! How much: 15 chf Sign up here: https://espace.cern.ch/club-fitness/Lists/Test_Subscription/NewForm.aspx? Join the Party and dance yourself into shape at Marco + Marials Zumba Masterclass. Saturday 30 June 2012 from 15:00 to 16:30 Marco + Mariel’s Zumba Masterclass Where: 216 (Pump room – equipped with changing rooms and showers). What to wear: comfortable clothes and indoor sports shoes + bring a drink! How much: 25 chf Sign up here: https://espace.cern.ch/club-fitness/Lists/Zumba%20...

  18. Fitness Club

    CERN Multimedia

    Fitness Club

    2012-01-01

      The CERN Fitness Club is pleased to announce its new early morning class which will be taking place on: Tuesdays from 24th April 07:30 to 08:15 216 (Pump Hall, close to entrance C) – Facilities include changing rooms and showers. The Classes: The early morning classes will focus on workouts which will help you build not only strength and stamina, but will also improve your balance, and coordination. Our qualified instructor Germana will accompany you throughout the workout  to ensure you stay motivated so you achieve the best results. Sign up and discover the best way to start your working day full of energy! How to subscribe? We invite you along to a FREE trial session, if you enjoy the activity, please sign up via our website: https://espace.cern.ch/club-fitness/Activities/SUBSCRIBE.aspx. * * * * * * * * Saturday 28th April Get in shape for the summer at our fitness workshop and zumba dance party: Fitness workshop with Germana 13:00 to 14:30 - 216 (Pump Hall) Price...

  19. Fitness club

    CERN Multimedia

    Fitness club

    2013-01-01

      Nordic Walking Classes Come join the Nordic walking classes and outings offered by the CERN Fitness Club starting September 2013. Our licensed instructor Christine offers classes for people who’ve never tried Nordic Walking and who would like to learn the technique, and outings for people who have completed the classes and enjoy going out as a group. Course 1: Tuesdays 12:30 - 13:30 24 September, 1 October, 8 October, 15 October Course 2: Tuesdays 12:30 - 13:30 5 November, 12 November, 19 November, 26 November Outings will take place on Thursdays (12:30 to 13:30) from 12 September 2013. We meet at the CERN Club Barracks car park (close to Entrance A) 10 minutes before departure. Prices: 50 CHF for 4 classes, including the 10 CHF Club membership. Payments made directly to instructor. Renting Poles: Poles can be rented from Christine at 5 CHF / hour. Subscription: Please subscribe at: http://cern.ch/club-fitness Looking forward to seeing you among us! Fitness Club FitnessClub@c...

  20. 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

  1. Method of making a cyanate ester foam

    Science.gov (United States)

    Celina, Mathias C.; Giron, Nicholas Henry

    2014-08-05

    A cyanate ester resin mixture with at least one cyanate ester resin, an isocyanate foaming resin, other co-curatives such as polyol or epoxy compounds, a surfactant, and a catalyst/water can react to form a foaming resin that can be cured at a temperature greater than 50.degree. C. to form a cyanate ester foam. The cyanate ester foam can be heated to a temperature greater than 400.degree. C. in a non-oxidative atmosphere to provide a carbonaceous char foam.

  2. Stretching and folding mechanism in foams

    Energy Technology Data Exchange (ETDEWEB)

    Tufaile, Alberto [Escola de Artes, Ciencias e Humanidades, Soft Matter Laboratory, Universidade de Sao Paulo, 03828-000 Sao Paulo, SP (Brazil)], E-mail: tufaile@usp.br; Pedrosa Biscaia Tufaile, Adriana [Escola de Artes, Ciencias e Humanidades, Soft Matter Laboratory, Universidade de Sao Paulo, 03828-000 Sao Paulo, SP (Brazil)

    2008-10-13

    We have described the stretching and folding of foams in a vertical Hele-Shaw cell containing air and a surfactant solution, from a sequence of upside-down flips. Besides the fractal dimension of the foam, we have observed the logistic growth for the soap film length. The stretching and folding mechanism is present during the foam formation, and this mechanism is observed even after the foam has reached its respective maximum fractal dimension. Observing the motion of bubbles inside the foam, large bubbles present power spectrum associated with random walk motion in both directions, while the small bubbles are scattered like balls in a Galton board.

  3. Cognitive fitness.

    Science.gov (United States)

    Gilkey, Roderick; Kilts, Clint

    2007-11-01

    Recent neuroscientific research shows that the health of your brain isn't, as experts once thought, just the product of childhood experiences and genetics; it reflects your adult choices and experiences as well. Professors Gilkey and Kilts of Emory University's medical and business schools explain how you can strengthen your brain's anatomy, neural networks, and cognitive abilities, and prevent functions such as memory from deteriorating as you age. The brain's alertness is the result of what the authors call cognitive fitness -a state of optimized ability to reason, remember, learn, plan, and adapt. Certain attitudes, lifestyle choices, and exercises enhance cognitive fitness. Mental workouts are the key. Brain-imaging studies indicate that acquiring expertise in areas as diverse as playing a cello, juggling, speaking a foreign language, and driving a taxicab expands your neural systems and makes them more communicative. In other words, you can alter the physical makeup of your brain by learning new skills. The more cognitively fit you are, the better equipped you are to make decisions, solve problems, and deal with stress and change. Cognitive fitness will help you be more open to new ideas and alternative perspectives. It will give you the capacity to change your behavior and realize your goals. You can delay senescence for years and even enjoy a second career. Drawing from the rapidly expanding body of neuroscience research as well as from well-established research in psychology and other mental health fields, the authors have identified four steps you can take to become cognitively fit: understand how experience makes the brain grow, work hard at play, search for patterns, and seek novelty and innovation. Together these steps capture some of the key opportunities for maintaining an engaged, creative brain.

  4. Enhanced rhamnolipids production via efficient foam-control using stop valve as a foam breaker.

    Science.gov (United States)

    Long, Xuwei; Shen, Chong; He, Ni; Zhang, Guoliang; Meng, Qin

    2017-01-01

    In this study, a stop valve was used as a foam breaker for dealing with the massive overflowing foam in rhamnolipid fermentation. As found, a stop valve at its tiny opening could break over 90% of the extremely stable rhamnolipid foam into enriched liquid when foam flows through the sharp gap in valve. The efficient foam-control by the stop valve considerably improved the rhamnolipid fermentation and significantly enhanced the rhamnolipid productivity by 83% compared to the regular fermentation. This efficient foam breaking was mainly achieved by a high shear rate in combination with fast separation of air from the collapsed foam. Altogether, the stop valve possessed a great activity in breaking rhamnolipid foam, and the involving mechanism holds the potential for developing efficient foam breakers for industrial rhamnolipid fermentation.

  5. Physisorption of ammonia on AISI 304L stainless steel at different surface temperature under high vacuum conditions

    Directory of Open Access Journals (Sweden)

    A. de Castro

    2016-12-01

    Full Text Available The physisorption of ammonia molecules (sticking on the walls of a stainless steel pipe (AISI 304L has been studied at different wall temperatures (323-473K. The total amount of ammonia that is retained on the walls, once equilibrium is reached, has been measured by differentially-pumped mass spectrometry in gas exposure laboratory experiments. The results show ammonia retentions in the range of μg/cm2 resulting in a multilayer adsorption with lower amounts of stuck ammonia at higher temperatures of the stainless steel surface. The sticking coefficient follows an exponential decay evolution with time. The activation energy of the process has been estimated by an Arrhenius fit, assuming that the characteristic time for this decay is inversely proportional to the kinetic adsorption constant. A value of 0.15eV per ammonia molecule has been obtained, being in agreement with nominal values for the physisorption of small molecules or atoms (CO, N2, Ar… that can be found in the specialized literature. The implication of these results in the possible extrapolation to the ITER vacuum system under nitrogen seeded plasma operation is also addressed.

  6. Non-Aqueous and Crude Oil Foams

    Directory of Open Access Journals (Sweden)

    Blázquez Christian

    2013-12-01

    Full Text Available Foams produced from non-aqueous media are less common than water-based foams but they play an important role in many industries and engineering processes. The low surface tension of hydrocarbon fluids limits the adsorption of common surface activity substances and different compounds and methods must be considered to generate and stabilize oil-based foam. Likewise, the destruction of unwanted non-aqueous based foam requires specific considerations not found with aqueous systems. Of particular interest are petroleum-based foams, which are highly complex due to the wide variety of compounds and gases that can be found. We provide an overview of the major mechanisms known to be important for non-aqueous foam stability with a spotlight on crude-oil foams.

  7. Viscous Control of the Foam Glass Process

    DEFF Research Database (Denmark)

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

    The production of foam glass as heat insulating material is an important industrial process because it enables low-cost recycling of glass waste from a variety of chemical compositions. Optimization of the foaming process of new glass waste compositions is time consuming, since many factors affect...... the foaming process such as temperature, particle size, type and concentration of foaming agent. The foaming temperature is one of the key factors, because even small temperature changes can affect the melt viscosity by several orders of magnitude. Therefore, it is important to establish the viscosity range...... in which the foaming process should take place, particularly when the type of recycled cullet is changed or several types of cullet are mixed in one batch. According to recent glass literature, the foaming process should occur at viscosity 103 to 105 Pa s. However, no systematic studies have hitherto been...

  8. Application of orthogonal array technique and particle swarm optimization approach in surface roughness modification when face milling AISI1045 steel parts

    Science.gov (United States)

    Azadi Moghaddam, Masoud; Kolahan, Farhad

    2016-12-01

    Face milling is an important and common machining operation because of its versatility and capability to produce various surfaces. Face milling is a machining process of removing material by the relative motion between a work piece and rotating cutter with multiple cutting edges. It is an interrupted cutting operation in which the teeth of the milling cutter enter and exit the work piece during each revolution. This paper is concerned with the experimental and numerical study of face milling of AISI1045. The proposed approach is based on statistical analysis on the experimental data gathered using Taguchi design matrix. Surface roughness is the most important performance characteristics of the face milling process. In this study the effect of input face milling process parameters on surface roughness of AISI1045 steel milled parts have been studied. The input parameters are cutting speed ( v), feed rate ( f z ) and depth of cut ( a p ). The experimental data are gathered using Taguchi L9 design matrix. In order to establish the relations between the input and the output parameters, various regression functions have been fitted on the data based on output characteristics. The significance of the process parameters on the quality characteristics of the process was also evaluated quantitatively using the analysis of variance method. Then, statistical analysis and validation experiments have been carried out to compare and select the best and most fitted models. In the last section of this research, mathematical model has been developed for surface roughness prediction using particle swarm optimization (PSO) on the basis of experimental results. The model developed for optimization has been validated by confirmation experiments. It has been found that the predicted roughness using PSO is in good agreement with the actual surface roughness.

  9. 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 an el...... brushing with fluoride toothpaste....

  10. Open-celled polyurethane foam

    Science.gov (United States)

    Russell, L. W.

    1970-01-01

    Open-celled polyurethane foam has a density of 8.3 pounds per cubic foot and a compressive strength of 295 to 325 psi. It is useful as a porous spacer in layered insulation and as an insulation material in vacuum tight systems.

  11. "Grinding" cavities in polyurethane foam

    Science.gov (United States)

    Brower, J. R.; Davey, R. E.; Dixon, W. F.; Robb, P. H.; Zebus, P. P.

    1980-01-01

    Grinding tool installed on conventional milling machine cuts precise cavities in foam blocks. Method is well suited for prototype or midsize production runs and can be adapted to computer control for mass production. Method saves time and materials compared to bonding or hot wire techniques.

  12. Foaming of Ethyl Hydroxyethyl Cellulose

    OpenAIRE

    Carrillo Agilera, Marc

    2015-01-01

    The current depletion of petroleum resources together with environmental issues have led to new approaches in plastic manufacturing. This trend involves using ecofriendly materials coming from renewable resources. Good candidates for this, due to their properties and availability, are the cellulose derivatives. Some of them, such as hydroxypropyl methylcellulose (HPMC), showed in previous studies a promising behavior when making polymeric foams. Unfortunately, the corresponding...

  13. Vacuum forming of thermoplastic foam

    NARCIS (Netherlands)

    Akkerman, Remko; Pronk, Ruud

    1999-01-01

    The process of thermoforming of foam sheet is analyzed using both finite element modeling and experiments. A simple constitutive model for finite tensile deformations of closed cellular material around its glass transition temperature is proposed, starting from well-known results from Gibson and Ash

  14. Multiscale modelling of evolving foams

    Science.gov (United States)

    Saye, R. I.; Sethian, J. A.

    2016-06-01

    We present a set of multi-scale interlinked algorithms to model the dynamics of evolving foams. These algorithms couple the key effects of macroscopic bubble rearrangement, thin film drainage, and membrane rupture. For each of the mechanisms, we construct consistent and accurate algorithms, and couple them together to work across the wide range of space and time scales that occur in foam dynamics. These algorithms include second order finite difference projection methods for computing incompressible fluid flow on the macroscale, second order finite element methods to solve thin film drainage equations in the lamellae and Plateau borders, multiphase Voronoi Implicit Interface Methods to track interconnected membrane boundaries and capture topological changes, and Lagrangian particle methods for conservative liquid redistribution during rearrangement and rupture. We derive a full set of numerical approximations that are coupled via interface jump conditions and flux boundary conditions, and show convergence for the individual mechanisms. We demonstrate our approach by computing a variety of foam dynamics, including coupled evolution of three-dimensional bubble clusters attached to an anchored membrane and collapse of a foam cluster.

  15. Fitness Club

    CERN Multimedia

    Fitness Club

    2012-01-01

    Nordic Walking Classes Sessions of four classes of one hour each are held on Tuesdays. RDV barracks parking at Entrance A, 10 minutes before class time. Session 1 =  11.09 / 18.09 / 25.09 / 02.10, 18:15 - 19:15 Session 2 = 25.09 / 02.10 / 09.10 / 16.10, 12:30 - 13:30 Session 3 = 23.10 / 30.10 / 06.11 / 13.11, 12:30 - 13:30 Session 4 = 20.11 / 27.11 / 04.12 / 11.12, 12:30 - 13:30 Prices 40 CHF per session + 10 CHF club membership 5 CHF/hour pole rental Check out our schedule and enroll at http://cern.ch/club-fitness   Hope to see you among us!  fitness.club@cern.ch In spring 2012 there was a long-awaited progress in CERN Fitness club. We have officially opened a Powerlifting @ CERN, and the number of members of the new section has been increasing since then reaching 70+ people in less than 4 months. Powerlifting is a strength sport, which is simple as 1-2-3 and efficient. The "1-2-3" are the three basic lifts (bench press...

  16. Resistência à corrosão de junta dissimilar soldada pelo processo TIG composta pelos aços inoxidáveis AISI 316L e AISI 444

    Directory of Open Access Journals (Sweden)

    Luis Henrique Guilherme

    2014-03-01

    Full Text Available O aço inoxidável AISI 444 tornou-se uma opção para substituir a liga AISI 316L devido ao seu menor custo e satisfatória resistência à corrosão. Entretanto, o uso da liga AISI 444 no feixe tubular de trocadores de calor acarreta na soldagem de uma junta dissimilar. O presente estudo teve por objetivo avaliar a resistência à corrosão da junta tubo-espelho soldada pelo processo TIG composta pelas ligas AISI 316L e AISI 444. A manufatura das amostras consistiu em replicar o projeto da junta tubo-espelho de trocadores de calor. Realizou-se em juntas soldadas ensaios de sensitização, perda de massa por imersão desde a temperatura ambiente até 90 ºC, e ensaios eletroquímicos de polarização potenciodinâmica nos eletrólitos 0,5 mol/L de HCl e 0,5 mol/L de H2SO4. Os resultados mostraram que a junta dissimilar sofreu corrosão galvânica com maior degradação na zona afetada pelo calor (ZAC do tubo AISI 444. Porém, os mecanismos de corrosão localizada (pite e intergranular demonstraram ser mais ativos para a liga AISI 316L. Conclui-se que a junta dissimilar apresentou melhor resistência à corrosão do que a junta soldada composta unicamente pela liga AISI 316L em temperaturas de até 70 ºC, conforme as condições observadas neste trabalho.

  17. Effect of heat treatment on an AISI 304 austenitic stainless steel evaluated by the ultrasonic attenuation coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Moghanizadeh, Abbas; Farzi, Abolfazl [Islamic Azad Univ., Esfarayen (Iran, Islamic Republic of). Dept. of Civil Engineering

    2016-07-01

    The properties of metals can be substantially changed by various methods, one of them is using heat treatment processes. Moreover, ultrasonic testing is the most preferred and effective, nondestructive testing technique for characterization of mechanical material properties. Austenitic stainless steel AISI 304 serves in many applications due to high strength and corrosion resistance. In certain applications, it is important to evaluate the mechanical properties of AISI 304 stainless steel. In this study, the ultrasonic method (attenuation measurement technique) is used to evaluate the hardness of AISI 304 stainless steel samples which were heat treated at different levels. Due to the heat treatment process, each sample has its specific microstructure and hardness which attenuate ultrasonic waves appropriately. The ultrasonic and hardness test show that it is possible to evaluate the hardness of AISI 304 stainless steel by ultrasonic attenuation coefficient. In addition, the relationship between ultrasonic attenuation coefficients and time of heat treatment is investigated.

  18. 46 CFR 108.463 - Foam rate: Protein.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Foam rate: Protein. 108.463 Section 108.463 Shipping... EQUIPMENT Fire Extinguishing Systems Foam Extinguishing Systems § 108.463 Foam rate: Protein. (a) If the outlets of a protein foam extinguishing system are in a space, the foam rate at each outlet must be at...

  19. Acoustic properties of aluminium foams

    Directory of Open Access Journals (Sweden)

    García, L. E.

    2008-09-01

    Full Text Available The article discusses normal incidence sound absorption by aluminium foam manufactured with powder metallurgy technology. Aluminium foams with different surface morphologies were obtained by varying the type of precursor and adding filler materials during the foaming process. The sound absorption coefficients found for these aluminium foams were compared to the coefficient for commercial foams marketed under the name ALPORAS. The effect of foam thickness on the absorption coefficient was studied for each sample prepared. The combination of good acoustic and mechanical properties makes aluminium foams particularly attractive products. The study included an analysis of the effect of 2-, 5- and 10-cm air gaps on the sound absorption coefficient. The results showed that such gaps, which are routinely used in construction to reduce the reverberation period in indoor premises, raised the low frequency absorption coefficient significantly. This increase was found to depend on aluminium foam density and thickness and the depth of the air gap. In this same line, we have investigated the absorption coefficient of the aluminium foams combined with a mineral fiber panel.Se presenta un estudio del coeficiente de absorción acústica a incidencia normal de espumas de aluminio fabricadas mediante la técnica pulvimetalúrgica. Se fabricaron espumas de aluminio de distinta morfología superficial variando el tipo de precursor y usando materiales de relleno durante el proceso de espumación. Se muestra un estudio comparativo del coeficiente de absorción acústica de las espumas de aluminio fabricadas y las espumas comerciales conocidas como ALPORAS. Para cada muestra fabricada se estudió la influencia del espesor sobre el valor del coeficiente de absorción.El atractivo de las espumas de aluminio radica en que en ellas se combinan interesantes propiedades acústicas y mecánicas. Se analizó el efecto de una cámara de aire de 2, 5 y 10 cm de anchura sobre el

  20. Fitness club

    CERN Multimedia

    Fitness club

    2013-01-01

    Nordic Walking Classes New session of 4 classes of 1 hour each will be held on Tuesdays in May 2013. Meet at the CERN barracks parking at Entrance A, 10 minutes before class time. Dates and time: 07.05, 14.05, 21.05 and 28.05, fom  12 h 30 to 13 h 30 Prices: 40 CHF per session + 10 CHF club membership – 5 CHF / hour pole rental Check out our schedule and enroll at http://cern.ch/club-fitness Hope to see you among us! 

  1. Effect of Foamed Pattern Density on the Lost Foam Process

    Directory of Open Access Journals (Sweden)

    T. Pacyniak

    2007-07-01

    Full Text Available The study examines the effect of the foamed polystyrene pattern density on the process of making castings by the lost foam technique with emphasis put on the analysis of simulation tests. The simulation regarded the effect that pattern density is said to have on the mould cavity filling rate, pressure in the gas gap, and size of this gap. For simulation tests of the full mould process, a mathematical model presented in this study was used. For calculations, the author's own algorithm was applied. The investigations have proved that with decreasing pattern density the pouring rate increases, while pressure in the gas gap and the size of the gap are decreasing. The increasing pouring rate ensures correct making of castings, even if their shapes are very intricate and the wall cross-sections are very small. Smaller size of the gas gap and lower pressure of gases in this gap reduce the risk of mould damage. The author’s own investigations have proved a very significant effect of the density of foamed polystyrene pattern on the casting process, and specially on the mould pouring rate. The best pouring rate is ensured by patterns of the density comprised in a range of ρ2 =18÷25 kg/m3.

  2. Cell Structure Evolution of Aluminum Foams Under Reduced Pressure Foaming

    Science.gov (United States)

    Cao, Zhuokun; Yu, Yang; Li, Min; Luo, Hongjie

    2016-09-01

    Ti-H particles are used to increase the gas content in aluminum melts for reduced pressure foaming. This paper reports on the RPF process of AlCa alloy by adding TiH2, but in smaller amounts compared to traditional process. TiH2 is completely decomposed by stirring the melt, following which reduced pressure is applied. TiH2 is not added as the blowing agent; instead, it is added for increasing the H2 concentration in the liquid AlCa melt. It is shown that pressure change induces further release of hydrogen from Ti phase. It is also found that foam collapse is caused by the fast bubble coalescing during pressure reducing procedure, and the instability of liquid film is related to the significant increase in critical thickness of film rupture. A combination of lower amounts of TiH2, coupled with reduced pressure, is another way of increasing hydrogen content in the liquid aluminum. A key benefit of this process is that it provides time to transfer the molten metal to a mold and then apply the reduced pressure to produce net shape foam parts.

  3. Blood Flow through an Open-Celled Foam

    Science.gov (United States)

    Ortega, Jason; Maitland, Duncan

    2011-11-01

    The Hazen-Dupuit-Darcy (HDD) equation is commonly used in engineering applications to model the pressure gradient of flow through a porous media. One major advantage of this equation is that it simplifies the complex geometric details of the porous media into two coefficients: the permeability, K, and form factor, C. However through this simplification, the flow details within the porous media are no longer accessible, making it difficult to study the phenomena that contribute to changes in K and C due to clotting of blood flow. To obtain a more detailed understanding of blood flow through a porous media, a direct assessment of the complex interstitial geometry and flow is required. In this study, we solve the Navier-Stokes equations for Newtonian and non-Newtonian blood flow through an open-celled foam geometry obtained from a micro-CT scan. The nominal strut size of the foam sample is of O(10e-5) m and the corresponding Reynolds number based upon this length ranges up to O(10). Fitting the pressure gradient vs. Darcy velocity data with the HDD equation demonstrates that both viscous and inertial forces play an important role in the flow through the foam at these Reynolds numbers. Recirculation zones are observed to form in the wake of the pore struts, producing regions of flow characterized by both low shear rates and long fluid residence times, factors of which have been shown in previous studies to promote blood clotting.

  4. 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 size is ≤33 μm (D50). The foams have a homogeneous pore distribution and a major fraction of the pores are smaller than 0.5 mm. Only when using the smallest particles (13 μm) does the pore size increase to 1......–3 mm due to a faster coalescence process. However, by quenching the sample from the foaming to the annealing temperature the pore size is reduced by a factor of 5–10. The foams with an apparent density of

  5. Foam-oil interaction in porous media: implications for foam assisted enhanced oil recovery.

    Science.gov (United States)

    Farajzadeh, R; Andrianov, A; Krastev, R; Hirasaki, G J; Rossen, W R

    2012-11-15

    The efficiency of a foam displacement process in enhanced oil recovery (EOR) depends largely on the stability of foam films in the presence of oil. Experimental studies have demonstrated the detrimental impact of oil on foam stability. This paper reviews the mechanisms and theories (disjoining pressure, coalescence and drainage, entering and spreading of oil, oil emulsification, pinch-off, etc.) suggested in the literature to explain the impact of oil on foam stability in the bulk and porous media. Moreover, we describe the existing approaches to foam modeling in porous media and the ways these models describe the oil effect on foam propagation in porous media. Further, we present various ideas on an improvement of foam stability and longevity in the presence of oil. The outstanding questions regarding foam-oil interactions and modeling of these interactions are pointed out. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Probing nanodispersions of clays for reactive foaming.

    Science.gov (United States)

    Harikrishnan, G; Lindsay, Chris I; Arunagirinathan, M A; Macosko, Christopher W

    2009-09-01

    Nanodispersions of clays in polyurethane components have been prepared. Nanoclays (both natural and organically modified) of various aspect ratios are used. The fillers are dispersed separately in polyurethane components, viz., polyol and polyisocyanate. The nanodispersions are characterized by the combined use of solution rheology, X-ray scattering, cryo-electron microscopy, and IR spectroscopy. Reactive foaming of these nanodispersions is carried out to make polyurethane nanocomposite foams. The status of the dispersion of fillers in components and in foams has been compared to investigate the effect of the foaming process in exfoliation. Interpretation of the results from different characterization techniques describes the state of the dispersion of fillers in components and in foam. The rheological and physicochemical behaviors of nanodispersions are shown to have a significant influence on the properties of nanocomposite foams.

  7. 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.

  8. Picture analysing method of slag foaming behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Juhart, M.; Peter, M.; Koch, K. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Metallurgy; Lamut, J. [Faculty of Natural Science and Technology, Univ. Ljubljana, Ljubljana (Slovenia)

    2001-03-01

    Hot tests of foaming behaviour of steelmaking slags were conducted on a laboratory scale up to 1760 C using a Tammann furnace. The foaming behaviour of the slags was quantified on the basis of a new measuring method. The volume increase and the progress of the foaming process can be continuously observed and calculated by means of picture analysis. The gas content of foaming slags was compared with the results of the measurements performed in steel plants. The influence of the magnesia content on the foaming behaviour is investigated. The chemical composition of the slag is beside the CO evolution the decisive factor influencing slag foaming behaviour. The highest volume increase values observed lie in the region of 2500% in relation to the initial volume. (orig.)

  9. Application and future of solid foams

    Science.gov (United States)

    Bienvenu, Yves

    2014-10-01

    To conclude this series of chapters on solid foam materials, a review of industrial current applications and of mid-term market perspectives centred on manmade foams is given, making reference to natural cellular materials. Although the polymeric foam industrial development overwhelms the rest and finds applications on many market segments, more attention will be paid to the emerging market of inorganic-especially metallic-foams (and cellular materials) and their applications, present or upcoming. It is shown that the final applications of solid foams are primarily linked to transport and the present-day development of the different classes of solid foams is contrasted between functional applications and structural applications. xml:lang="fr"

  10. 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.

  11. 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...... an electronic search for literature published in English between 2003 and 2014. The included papers were assessed for their risk of bias and the results were narratively synthesized due to study heterogeneity. The quality of evidence was expressed according to GRADE. RESULTS: A total of 19 papers were included...... (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...

  12. Models for metallic foam lamellae

    Science.gov (United States)

    Gratton, Michael B.; Davis, Stephen H.

    2010-11-01

    We consider a pure liquid film with two liquid-gas interfaces --- a free film --- in two dimensions. Assuming that the aspect ratio of the film thickness to the arc length of the center-line is small, we develop a set of models using lubrication theory for the evolution of the film including the effects of different gas pressures above and below the liquid as well as strong surface tension. These models show a separation of timescales between center-line relaxation, thickness averaging, and drainage due to an applied pressure gradient along the film. Interpreted in the case of surfactant-free foams, these results show that the lamella separating two bubbles in an unstable foam will quickly assume a center-line that is an arc of a circle. Thereafter, the film will become uniform in thickness and drain due to capillary suction from adjoining Plateau borders.

  13. Análisis experimental del torneado de alta velocidad del acero AISI 1045 // Experimental analysis of high speed turning of AISI 1045 steel gears

    Directory of Open Access Journals (Sweden)

    Luís Wilfredo Hernández‐González

    2012-01-01

    Full Text Available El objetivo de este trabajo es el estudio experimental de la evolución del desgaste del flanco de dosinsertos de carburo recubiertos y un cermet, durante el torneado en seco del acero AISI 1045 con 500 y600 m/min de velocidad de corte. Los resultados fueron comparados utilizando el análisis de varianza y deregresión. La investigación mostró un efecto significativo de la velocidad de corte y del tiempo demaquinado en el desgaste del flanco. El mejor desempeño fue para el carburo recubierto con tres capas,mientras que a elevada velocidad de corte el carburo con dos capas sufrió el mayor desgaste, lo cual sedebe a que cuando pierde sus recubrimientos el substrato del inserto queda desprotegido y el desgastecrece rápidamente por la extremas condiciones del mecanizado por alta velocidad. Además, se planteanrecomendaciones del tiempo de maquinado de los insertos dadas las condiciones de elaboración por altavelocidad.Palabras claves: torneado de alta velocidad, desgaste del flanco, acero AISI 1045, estudio experimental.__________________________________________________________________________AbstractThis work deals with the experimental study of the flank wear evolution of two coating carbide inserts and acermet insert during the dry turning of AISI 1045 steel with 500 and 600 m/min cutting speed. The resultswere compared using the variance and regression analysis. The investigation showed a significant effectof cutting speed and machining time on the flank wear in high speed machining. The three coating layersinsert showed the best performance while the two layers insert had the worst behaviour of the cutting toolwear at high cutting speed, this is because once the coating film is peeled off, the substrate of the insertbecomes uncovered and the wear grows rapidly due to the extreme machining conditions for high speed.Besides, the machining time recommendations of inserts for the cutting conditions at high speed areexposed.Key words: high

  14. Rolling Contact Fatigue Life and Spall Propagation Characteristics of AISI M50, M50 NiL, and AISI 52100. Part 1. Experimental Results (Preprint)

    Science.gov (United States)

    2009-10-01

    factors to the L-P life model are currently used as standard practice to account for improvements in bearing material cleanliness and processing...eleven 12.7 mm diameter ABMA Grade 10 silicon nitride (Si3N4) balls, Ra finish of 6.4 nm and one piece machined silver plated AISI 4340 steel cages...piloted on both sides of the outer ring. The outer ring cage- land shoulders of the M50NiL bearings were titanium nitride (TiN) coated per aerospace

  15. Synthesis of CO2 Copolymer Based Polyurethane Foams

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    CO2-copolymer based polyurethane foams were synthesized and characterized in this paper. The foams were found to have higher strength and lower heat of combustion than the conventional polyether polyurethane foams. They may find wide applications in many fields.

  16. Hydrophobins, beer foaming and gushing

    OpenAIRE

    Shokribousjein, Zahra; Deckers, Sylvie; Gebruers, Kurt; Lorgouilloux, Yannick; Baggerman, Geert; Verachtert, Hubert; Delcour, Jan; Etienne, Pierre; Rock, Jean-Marie; Michiels, Chris; Derdelinckx, Guy

    2011-01-01

    Hydrophobins belong to the most important proteins produced by filamentous fungi. They are surface active and their foaming potential is due to the presence of particular spatial arrangements of hydrophobic and hydrophilic amino acids. However, their presence eventually leads to overfoaming of beers. In beers and other liquids hydrophobin molecules aggregate around hydrophobic carbon dioxide molecules and form nano-structures, containing entrapped carbon dioxide. By pressure relea...

  17. Microcellular foams made from gliadin

    OpenAIRE

    Quester, S; Dahesh, M.; Strey, R.

    2014-01-01

    We have generated closed-cell microcellular foams from gliadin, an abundantly available wheat storage protein. The extraction procedure of gliadin from wheat gluten, which involves only the natural solvents water and ethanol, respectively, is described with emphasis on the precipitation step of gliadin which results in a fine dispersion of mostly spherical, submicron gliadin particles composed of myriad of protein molecules. A dense packing of these particles was hydrated and subjected to an ...

  18. B-Plant canyon fire foam supply

    Energy Technology Data Exchange (ETDEWEB)

    Gainey, T.

    1995-01-01

    A new raw water supply was installed for the B-Plant fire foam system. This document details tests to be performed which will demonstrate that the system can function as designed. The tests include: Verification of the operation of the automatic valves at the cells; Measurement of water flow and pressure downstream of the proportioner; Production of foam, and measurement of foam concentration. Included as an appendix is a copy of the work package resolution (J4 & J4a).

  19. Aqueous foam toxicology evaluation and hazard review

    Energy Technology Data Exchange (ETDEWEB)

    Archuleta, M.M.

    1995-10-01

    Aqueous foams are aggregates of bubbles mechanically generated by passing air or other gases through a net, screen, or other porous medium that is wetted by an aqueous solution of surface-active foaming agents (surfactants). Aqueous foams are important in modem fire-fighting technology, as well as for military uses for area denial and riot or crowd control. An aqueous foam is currently being developed and evaluated by Sandia National Laboratories (SNL) as a Less-Than-Lethal Weapon for the National Institute of Justice (NIJ). The purpose of this study is to evaluate the toxicity of the aqueous foam developed for the NIJ and to determine whether there are any significant adverse health effects associated with completely immersing individuals without protective equipment in the foam. The toxicity of the aqueous foam formulation developed for NIJ is determined by evaluating the toxicity of the individual components of the foam. The foam is made from a 2--5% solution of Steol CA-330 surfactant in water generated at expansion ratios ranging from 500:1 to 1000:1. SteoI CA-330 is a 35% ammonium laureth sulfate in water and is produced by Stepan Chemical Company and containing trace amounts (<0.1%) of 1,4-dioxane. The results of this study indicate that Steol CA-330 is a non-toxic, mildly irritating, surfactant that is used extensively in the cosmetics industry for hair care and bath products. Inhalation or dermal exposure to this material in aqueous foam is not expected to produce significant irritation or systemic toxicity to exposed individuals, even after prolonged exposure. The amount of 1,4-dioxane in the surfactant, and subsequently in the foam, is negligible and therefore, the toxicity associated with dioxane exposure is not significant. In general, immersion in similar aqueous foams has not resulted in acute, immediately life-threatening effects, or chronic, long-term, non-reversible effects following exposure.

  20. Thermal Affects Of Impact Testing Polymer Foams

    Science.gov (United States)

    Roberts, Charles C.

    1984-03-01

    Impacting polymer foams results in a thermal pattern on the surface of the polymer due to energy dissipation and transmission affects. Five polymer foams were tested using two types of ballistic pendulums as impact devices. The transient thermal pattern was recorded on video tape using an infrared scanner. Differing internal energy dissipation mechanisms were detected depending on the type of foam. Temperature distributions were indicative of pendulum penetration, energy dissipation, shock attenuation and transmittance.

  1. Starch/fiber/poly(lactic acid) foam and compressed foam composites

    Science.gov (United States)

    Composites of starch, fiber, and poly(lactic acid) (PLA) were made using a foam substrate formed by dehydrating starch or starch/fiber gels. PLA was infiltrated into the dry foam to provide better moisture resistance. Foam composites were compressed into plastics using force ranging from 4-76MPa. Te...

  2. Shock compression of polyurethane foams

    Directory of Open Access Journals (Sweden)

    Stahl D.B.

    2012-08-01

    Full Text Available Several shock studies have been made on polyurethane materials, both fully dense and distended in the form of foams. However, there is a lack of shock data between the densities of 0.321 and 1.264g/cm3 (fully dense. We present here data obtained from two different types of shock experiments at densities of 0.35, 0.5, 0.68, 0.78, and 0.9g/cm3 in order to fill in the density deficiencies and make it easier to develop an unreacted equation of state (EOS for polyurethane as a function of density. A thermodynamically consistent EOS was developed, based on the Helmholtz free energy, and was used to predict the shock properties of polyurethane materials at densities from 1.264 to 0.348g/cm3. These estimates are compared to the available data. The data match quite close to the predictions and provide a basis for calculating polyurethane foam shock processes. Chemical reaction has been observed at relatively high pressure (21.7 GPa in fully dense polyurethane in an earlier study, and the equation of state presented here is representative of the unreacted polyurethane foam. Lowering the density is expected to drop the shock pressure for chemical reaction, yet there is not enough data to address the low density shock reaction thresholds in this study.

  3. Cells on foam and fiber

    Energy Technology Data Exchange (ETDEWEB)

    Clyde, R. [Clyde Engineering, New Orleans, LA (United States)

    1996-12-31

    Cells grow on high area foam and, when a screen is put around the foam, it is made heavier so it can be fluidized. When foam is rotated in a half full RBC (rotary biological contactor), drops are formed and mass transfer of oxygen to drops is much faster. Most fungi and some mammalian cells need oxygen. Corrugated fibers with holes in the valleys also produce drops. White rot fungus needs oxygen and it degrades many chlorine compounds, azo dyes, PAHs (polycyclic aromatic hydrocarbons), and TNT. Old cardboard boxes are readily available and when buried in soil, oxygen is entrapped. In a lake, the boxes expose high area. Celite entrapped in fibers provides even more area. Fibers have high surface area for immobilizing cells and, when the fibers are rotated, fast reactions occur, converting one chemical to another. Sugar has been fermented to alcohol in 10--15 minutes. Ethanol has high octane and does not need lead. Old cars and trucks still use lead, and high levels have been found in the drinking water of several large cities. Bacteria on fibers can remove lead in a few seconds. When an RBC of plain fiber discs is rotated and a light shone in the tope, the light hits a thin moving film to degrade chlorine compounds and sterilize water. Titania can be fused to the fiberglass discs. Microbes and light remove sulfur from oil. Calcium magnesium acetate is a non-corrosive road deicer. Salt on roads causes millions of dollars damage to bridges and cars.

  4. Microgravity Foam Structure and Rheology

    Science.gov (United States)

    Durian, Douglas J.

    1997-01-01

    To exploit rheological and multiple-light scattering techniques, and ultimately microgravity conditions, in order to quantify and elucidate the unusual elastic character of foams in terms of their underlying microscopic structure and dynamics. Special interest is in determining how this elastic character vanishes, i.e. how the foam melts into a simple viscous liquid, as a function of both increasing liquid content and shear strain rate. The unusual elastic character of foams will be quantified macroscopically by measurement of the shear stress as a function of static shear strain, shear strain rate, and time following a step strain; such data will be analyzed in terms of a yield stress, a static shear modulus, and dynamical time scales. Microscopic information about bubble packing and rearrangement dynamics, from which these macroscopic non-Newtonian properties presumably arise, will be obtained non-invasively by novel multiple-light scattering diagnostics such as Diffusing-Wave Spectroscopy (DWS). Quantitative trends with materials parameters, such as average bubble size, and liquid content, will be sought in order to elucidate the fundamental connection between the microscopic structure and dynamics and the macroscopic rheology.

  5. Oxidation behavior of 26Cr-16Ni and AISI 309 austenitic stainless steels in air flow at 1,173 K

    Energy Technology Data Exchange (ETDEWEB)

    Pipatnukun, Peeraya; Wangyao, Panyawat; Lothongkum, Gobboon [Chulalongkorn Univ., Bangkok (Thailand). Dept. of Metallurgical Engineering

    2015-11-01

    This work investigates the isothermal oxidation behavior of as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309 at 1,173 K in air flow rate of 40 cm{sup 3} x min{sup -1} using thermogravimetric analysis (TGA). In 33 hours, the oxidation resistance declines from high to low are as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309, respectively. The oxidation kinetic results show that the exponential rate constant of the as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309 are 8.79 x 10{sup -6}, 4.02 x 10{sup -5} and 4.35 x 10{sup -5} g x cm{sup -2} x s{sup -n}, respectively. The exponential growth rates of as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309 are 0.42, 0.29 and 0.32, respectively. It indicates that the oxidation kinetic of as cast 26Cr-16Ni approaches a parabolic rate law, but those of as cold-rolled and as cast AISI 309 approach the cubic rate law. The sequence of oxide scale formations on the tested samples is also discussed.

  6. In Situ Observation of Solidification Process of AISI 304 Austenitic Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    HUANG Fu-xiang; WANG Xin-hua; ZHANG Jiong-ming; JI Chen-xi; FANG Yuan; YU Yan

    2008-01-01

    The solidification process of AISI 304 stainless steel during cooling at a rate of 0.05 K/s has been observed in situ using a confocal scanning laser microscope(CSLM).The results show that the δ phase appeared first in liquid steel,as the temperature decreased,the γ phase precipitated prior at δ-grain boundary at 1452.2℃,the liquid steel disappeared at 1431.3℃,and then theγphase precipitated on the δ ferrite.Based on the Scheil-GulliVer solidification model,the solidification processes of AISI 304 stainless steel are simulated using the Scheil model in Thermo-Calc.and the simulation results agree well with the results observed in the experiment.

  7. Characterization of the expanded austenite developed on AISI 316 LM steel by plasma nitriding

    Directory of Open Access Journals (Sweden)

    Keddam M.

    2017-01-01

    Full Text Available AISI 316 LM samples were plasma nitrided at a temperature of 380°C for different times between 0.5 and 8 h in a 85%N2- 15%H2 gas mixture. Different experimental techniques such as: optical microscopy (OM, X- ray diffraction (XRD and glow discharge optical emission spectroscopy (GDOES were used to characterize the expanded austenite layer formed at the surface of AISI 316 LM stainless steel. The microscopical observations revealed the presence of the expanded austenite with a mean layer thickness between 1.90 and 4.31 μm. The growth kinetics of expanded austenite was also investigated. In addition, both the compressive stresses in the expanded austenite layer and the compositional strains were estimated by means of a simple mechanical model based on the XRD results.

  8. Corrosion resistance of the welded AISI 316L after various surface treatments

    Directory of Open Access Journals (Sweden)

    Tatiana Liptáková

    2014-01-01

    Full Text Available The main aim of this work is to monitor the surface treatment impact on the corrosion resistance of the welded stainless steel AISI 316L to local corrosion forms. The excellent corrosion resistance of austenitic stainless steel is caused by the existence of stable, thin and well adhering passive layer which quality is strongly influenced by welding. Therefore surface treatment of stainless steel is very important with regard to its local corrosion susceptibility Surfaces of welded stainless steel were treated by various mechanical methods (grinding, garnet blasting. Surface properties were studied by SEM, corrosion resistance was evaluated after exposition tests in chlorides environment using weight and metalographic analysis. The experimental outcomes confirmed that the mechanical finishing has a significant effect on the corrosion behavior of welded stainless steel AISI 316L.

  9. Experimental study of mechanical properties of friction welded AISI 1021 steels

    Indian Academy of Sciences (India)

    Amit Handa; Vikas Chawla

    2013-12-01

    Friction welding is widely used as a mass production method in various industries. In the present study, an experimental set-up was designed in order to achieve friction welding of plastically deformed AISI 1021 steels. In this study, low alloy steel (AISI 1021) was welded under different welding parameters and afterwards the mechanical properties such as tensile strength, impact strength and hardness were experimentally determined. On the basis of the results obtained from the experimentation, the graphs were plotted. It is the strength of welded joints, which is fundamental property to the service reliability of the weldments and hence present work was undertaken to study the influence of axial pressure and rotational speed in friction welded joints. Axial pressure and rotational speed are the two major parameters which can influence the strength and hence the mechanical properties of the friction welded joints. Thus the axial pressure and rotational speed were taken as welding parameters, which reflect the mechanical properties.

  10. Behavior of AISI SAE 1020 Steel Implanted by Titanium and Exposed to Bacteria Sulphate Deoxidizer

    Science.gov (United States)

    Niño, Ely Dannier V.; Garnica, Hernán; Dugar-Zhabon, Veleriy; Castillo, Genis

    2014-05-01

    A hybrid technology to treat solid surfaces with the pulse high voltage and electric arc discharges of low pressure with a three-dimensional ion implantation technique (3DII) is applied. This technology is used to protect AISI SAE 1020 steel against a microbiological corrosion. The titanium ion implanted steel samples (coupons) are subjected to a medium of bacteria sulphate deoxidizer (BSD) which are very typical of the hydrocarbon industry and are potentially harmful for structures when are in contact with petroleum and some of its derivatives. The used technology aims to find an effective hybrid procedure to minimize the harmful effects of bacteria on AISI SAE 1020 steel. The hybrid technology efficiency of superficial titanium implantation is estimated through the measurements of the point corrosion characteristics obtained after testing both the treated and non-treated coupons. The three-dimensional surface structures of the samples are reconstructed with help of a confocal microscope.

  11. Finite Element Simulation and Experimental Verification of Internal Stress of Quenched AISI 4140 Cylinders

    Science.gov (United States)

    Liu, Yu; Qin, Shengwei; Hao, Qingguo; Chen, Nailu; Zuo, Xunwei; Rong, Yonghua

    2017-03-01

    The study of internal stress in quenched AISI 4140 medium carbon steel is of importance in engineering. In this work, the finite element simulation (FES) was employed to predict the distribution of internal stress in quenched AISI 4140 cylinders with two sizes of diameter based on exponent-modified (Ex-Modified) normalized function. The results indicate that the FES based on Ex-Modified normalized function proposed is better consistent with X-ray diffraction measurements of the stress distribution than FES based on normalized function proposed by Abrassart, Desalos and Leblond, respectively, which is attributed that Ex-Modified normalized function better describes transformation plasticity. Effect of temperature distribution on the phase formation, the origin of residual stress distribution and effect of transformation plasticity function on the residual stress distribution were further discussed.

  12. Evaluation of structural behaviour and corrosion resistant of austenitic AISI 304 and duplex AISI 2304 stainless steel reinforcements embedded in ordinary Portland cement mortars; Evaluacion del comportamiento estructural y de resistencia a la corrosion de armaduras de acero inoxidable austenitico AISI 304 y duplex AISI 2304 embebidas en morteros de cemento Portland

    Energy Technology Data Exchange (ETDEWEB)

    Medina, E.; Cobo, A.; Bastidas, D. M.

    2012-07-01

    The mechanical and structural behaviour of two stainless steels reinforcements, with grades austenitic EN 1.4301 (AISI 304) and duplex EN 1.4362 (AISI 2304) have been studied, and compared with the conventional carbon steel B500SD rebar. The study was conducted at three levels: at rebar level, at section level and at structural element level. The different mechanical properties of stainless steel directly influence the behaviour at section level and structural element level. The study of the corrosion behaviour of the two stainless steels has been performed by electrochemical measurements, monitoring the corrosion potential and the lineal polarization resistance (LPR), of reinforcements embedded in ordinary Portland cement (OPC) mortar specimens contaminated with different amount of chloride over one year time exposure. Both stainless steels specimens embedded in OPC mortar remain in the passive state for all the chloride concentration range studied after one year exposure. (Author) 26 refs.

  13. Finite Element Simulation and Experimental Verification of Internal Stress of Quenched AISI 4140 Cylinders

    Science.gov (United States)

    Liu, Yu; Qin, Shengwei; Hao, Qingguo; Chen, Nailu; Zuo, Xunwei; Rong, Yonghua

    2017-01-01

    The study of internal stress in quenched AISI 4140 medium carbon steel is of importance in engineering. In this work, the finite element simulation (FES) was employed to predict the distribution of internal stress in quenched AISI 4140 cylinders with two sizes of diameter based on exponent-modified (Ex-Modified) normalized function. The results indicate that the FES based on Ex-Modified normalized function proposed is better consistent with X-ray diffraction measurements of the stress distribution than FES based on normalized function proposed by Abrassart, Desalos and Leblond, respectively, which is attributed that Ex-Modified normalized function better describes transformation plasticity. Effect of temperature distribution on the phase formation, the origin of residual stress distribution and effect of transformation plasticity function on the residual stress distribution were further discussed.

  14. Sub-surface Fatigue Crack Growth at Alumina Inclusions in AISI 52100 Roller Bearings

    DEFF Research Database (Denmark)

    Cerullo, Michele

    2014-01-01

    Sub-surface fatigue crack growth at non metallic inclusions is studied in AISI 52100 bearing steel under typical rolling contact loads. A first 2D plane strain finite element analysis is carried out to compute the stress history in the innner race at a characteristic depth, where the Dang Van...... damage factor is highest. Subsequently the stress history is imposed as boundary conditions in a periodic unit cell model, where an alumina inclusion is embedded in a AISI 52100 matrix. Cracks are assumed to grow radially from the inclusion under cyclic loading. The growth is predicted by means...... of irreversible fatigue cohesive elements. Different orientations of the cracks and different matrix-inclusion bonding conditions are analyzed and compared....

  15. Boriding kinetics of Fe2B layers formed on AISI 1045 steel

    Directory of Open Access Journals (Sweden)

    Zuno-Silva J.

    2014-01-01

    Full Text Available In the present work, a diffusion model was suggested to study the growth kinetics of Fe2B layers grown on the AISI 1045 steel by the pack-boriding treatment. The generated boride layers were analyzed by optical microscopy and X-ray diffraction analysis. The applied diffusion model is based on the principle of mass conservation at the (Fe2B/ substrate interface. It was used to estimate the boron diffusion coefficients of Fe2B in the temperature range of 1123-1273 K. A validation of the model was also made by comparing the experimental Fe2B layer thickness obtained at 1253 K for 5 h of treatment with the predicted value. Basing on our experimental results, the boron activation energy was estimated as 180 kJ mol-1 for the AISI 1045 steel.

  16. Study of carbonitriding thermochemical treatment by plasma screen in active with pressures main austenitic stainless steels AISI 409 and AISI 316L; Estudo do tratamento termoquimico de carbonitretacao por plasma em tela ativa com pressoes variaveis nos acos inoxidaveis austenitico AISI 316L e ferririco AISI 409

    Energy Technology Data Exchange (ETDEWEB)

    Melo, M.S.; Oliveira, A.M.; Leal, V.S.; Sousa, R.R.M. de; Alves Junior, C. [Centro Federal de Educacao Tecnologica do Maranhao (CEFET/MA), Sao Luis, MA (Brazil); Centro Federal de Educacao Tecnologica do Piaui (CEFET/PI), Teresina, PI (Brazil); Universidade Federal do Rio Grande do Norte (DF/UFRN), Natal, RN (Brazil). Dept. de Fisica. Labplasma

    2010-07-01

    The technique called Active Screen Plasma Nitriding (ASPN) is being used as an alternative once it offers several advantages with respect to conventional DC plasma. In this method, the plasma does not form directly in the sample's surface but on a screen, in such a way that undesired effects such as the edge effect is minimized. Stainless steels present not very satisfactory wearing characteristics. However, plasma carbonitriding has been used as to improve its resistance to wearing due to the formation of a fine surface layer with good properties. In this work, samples of stainless steel AISI 316L and AISI 409 were treated at pressures of 2.5 and 5 mbar. After the treatments they were characterized by microhardness, microscopy and Xray diffraction. Microscopy and hardness analysis showed satisfactory layers and toughness in those steels. (author)

  17. In Vivo Evaluation of Hydroxyapatite Foams

    Directory of Open Access Journals (Sweden)

    Sepulveda P.

    2002-01-01

    Full Text Available Porous hydroxyapatite manufactured by foaming of aqueous ceramic suspensions and setting via gelcasting of organic monomers was tested for in vivo biocompatibility in rabbit tibia for a period of 8 weeks. The foams provide tortous frameworks and large interconnected pores that support cell attachment and organisation into 3D arrays to form new tissue. The HA foam implants were progressively filled with mature new bone tissue and osteoid after the implanted period, confirming the high osteoconductive potential and high biocompatibility of HA and the suitability of foam network in providing good osteointegration. No immune or inflammatory reactions were detected.

  18. Characterization of low density rigid urethane foam

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, F.N.

    1978-10-01

    The chemical and mechanical properties of a low density, rigid polyurethane foam material taken from a Joint Test Assembly (JTA) after 13 years of storage were measured. Chemical analyses confirmed the composition to be Bendix Rigifoam 6003-1.5, a pentaerythritol/epsilon-caprolactone/tolyene diisocyanate polyurethane foam. Comparison of data from testing thermal and mechanical characteristics with data from a currently manufactured foam of identical composition indicates no degradation of properties had occurred. This information gives added confidence to the stockpile lifetime integrity of the Rigifoam 6003-2 foam system designated for use in other programs.

  19. Heat-regulated foaming in surfactant solutions

    Energy Technology Data Exchange (ETDEWEB)

    Pletnev, M.Y.; Eremina, L.D.; Vlasenko, I.G.

    1984-01-01

    This article examines the mechanism of the foam-inhibiting action resulting from the use of propylene oxide derivatives in solutions both of anionic and of nonionic surfactants. The objective is the creation of a detergent composition with heat-regulated foaming, which would foam well at 30-50/sup 0/ and poorly at 80-90/sup 0/, which is the usual temperature of washing machines. It is demonstrated that foaming can be regulated by the variation of the cloud points of solutions with the aid of additions of polypropylene glycols and their alkyl derivatives or block copolymers in solutions of surfactants. Foaming and foam stability decrease sharply above the cloud points of the solutions due to the foam-inhibiting action of the coacervate phase on the coexisting foam-forming solution. The foam inhibition of polypropylene glycols increases and becomes apparent at lower concentrations with the increase of the average molecular weight of the hydrophobic blocks, the increase of their relative content (in block copolymers with oxyethylene groups), and upon the introduction of alkyl groups.

  20. One-step microwave foaming and curing

    Science.gov (United States)

    Gagliani, J.; Lee, R.; Sorathia, U. A. K.; Wilcoxson, A. L.

    1981-01-01

    Process that combines microwave foaming and curing of polyimide precursors in single step produces fire-resistant foam slabs of much larger volume than has previously been possible. By adding selected conductive fillers to powder precursors and by using high-power microwave oven, foam slabs with dimensions in excess of 61 by 61 by 7.6 cm are made. Typical foaming and curing and curing time is 35 minutes in microwave oven with additional 1 to 2 hour postcure in conventional oven.

  1. AC induction field heating of graphite foam

    Energy Technology Data Exchange (ETDEWEB)

    Klett, James W.; Rios, Orlando; Kisner, Roger

    2017-08-22

    A magneto-energy apparatus includes an electromagnetic field source for generating a time-varying electromagnetic field. A graphite foam conductor is disposed within the electromagnetic field. The graphite foam when exposed to the time-varying electromagnetic field conducts an induced electric current, the electric current heating the graphite foam. An energy conversion device utilizes heat energy from the heated graphite foam to perform a heat energy consuming function. A device for heating a fluid and a method of converting energy are also disclosed.

  2. Recent trends in aluminum foam sandwich technology

    Energy Technology Data Exchange (ETDEWEB)

    Banhart, John [TU Berlin, Materials Science and Technology, Hardenbergstr. 36, 10623 Berlin (Germany); Helmholtz-Centre Berlin, Hahn-Meitner-Platz, 14109 Berlin (Germany); Seeliger, Hans-Wolfgang [Pohltec Metalfoam GmbH, Robert-Bosch-Str. 6D, 50769 Koeln (Germany)

    2012-12-15

    We review the status of aluminum foam sandwich (AFS) technology and discuss both recent improvements of foaming technology and current application strategies. It is concluded that the quality of foams has improved in the past years but the costs are still very much the same. This is why applications in which metal foams have more than one function are more likely to be economically viable. The examples presented include electromagnetic shielding, carrier plates for mirrors, cooking equipment, architectural panels, and blast protection. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. TEPIC - A New High Temperature Structural Foam

    Energy Technology Data Exchange (ETDEWEB)

    Whinner, L L; Goods, S H; Tootle, M L; Neuschwanger, C L

    1998-10-01

    The formulation, processing characteristics, microstructure and mechanical properties of a new structural foam, suitable for use at service temperatures up to 200 degrees C, are reported. In each of the respects, the foam is compared to an existing material, called APO-BMI that is currently in use. When these two foams are directly compared, the new foam, called TEPIC, is found to be superior in its mechanical performance. TEPIC is formulated from a non-carcinogenic isocyanate, a di-functional epoxide, and glass microballoons. Compared to APO-BMI processing, TEPIC processing is facile and economical.

  4. Plasma-Spray Metal Coating On Foam

    Science.gov (United States)

    Cranston, J.

    1994-01-01

    Molds, forms, and other substrates made of foams coated with metals by plasma spraying. Foam might be ceramic, carbon, metallic, organic, or inorganic. After coat applied by plasma spraying, foam left intact or removed by acid leaching, conventional machining, water-jet cutting, or another suitable technique. Cores or vessels made of various foam materials plasma-coated with metals according to method useful as thermally insulating containers for foods, liquids, or gases, or as mandrels for making composite-material (matrix/fiber) parts, or making thermally insulating firewalls in automobiles.

  5. Estimation of Mechanical Properties of Stainless Steel AISI 410 by Small-Punch Testing (Erickson Test)

    Science.gov (United States)

    Hassan, A.-P.

    2014-07-01

    The small-punch testing (SPT) method is used for determining the mechanical properties of AISI 410 (0.14% C, 12% Cr) stainless steel. A thin disc-shaped specimen with known mechanical properties is pressed with a small ball until the appearance of cracks in the former. The load - displacement curves are recorded. Computation of the yield strength and fracture energy by the curve obtained and by known formulas shows good convergence with the characteristics obtained by standard testing.

  6. Friction welding of AA6061 to AISI 4340 using silver interlayer

    OpenAIRE

    Suresh D. Meshram; G. Madhusudhan Reddy

    2015-01-01

    The present work pertains to the study on joining of AA6061 and AISI 4340 through continuous drive friction welding. The welds were evaluated by metallographic examination, X-ray diffraction, electron probe microanalysis, tensile test and microhardness. The study reveals that the presence of an intermetallic compound layer at the bonded interface exhibits poor tensile strength and elongation. Mg in AA6061 near to the interface is found to be favourable for the formation and growth of Fe2Al5 i...

  7. Cathodic cage nitriding of AISI 409 ferritic stainless steel with the addition of CH4

    Directory of Open Access Journals (Sweden)

    Rômulo Ribeiro Magalhães de Sousa

    2012-04-01

    Full Text Available AISI 409 ferritic stainless steel samples were nitrided using the cathodic cage plasma nitriding technique (CCPN, with the addition of methane to reduce chromium precipitation, increase hardness and wear resistance and reduce the presence of nitrides when compared to plasma carbonitriding. Microhardness profiles and X-Ray analysis confirm the formation of a very hard layer containing mainly ε-Fe3N and expanded ferrite phases.

  8. Welding of AA1050 aluminum with AISI 304 stainless steel by rotary friction welding process

    OpenAIRE

    Chen Ying An; Francisco Piorino Neto; Eder Paduan Alves

    2010-01-01

    The purpose of this work was to assess the development of solid state joints of dissimilar material AA1050 aluminum and AISI 304 stainless steel, which can be used in pipes of tanks of liquid propellants and other components of the Satellite Launch Vehicle. The joints were obtained by rotary friction welding process (RFW), which combines the heat generated from friction between two surfaces and plastic deformation. Tests were conducted with different welding process parameters. The results we...

  9. Martensitic transformation during fatigue testing of an AISI 301LN steel

    OpenAIRE

    Mateo García, Antonio Manuel; Fargas Ribas, Gemma

    2012-01-01

    The plastic deformation accumulated during fatigue testing can induce the transformation of austenite to martensite in metastable austenitic stainless steels. To analyze this issue, a metastable austenitic stainless steel grade AISI 301 LN was studied in two different conditions, i.e. annealed and cold rolled. In the first case, the steel was fully austenitic, whereas cold rolled material had almost 30% of martensite. High cycle fatigue tests at a stress ratio of 0.8 were carried out on flat ...

  10. Martensitic Transformation in Ultrafine-Grained Stainless Steel AISI 304L Under Monotonic and Cyclic Loading

    Directory of Open Access Journals (Sweden)

    Heinz Werner Höppel

    2012-02-01

    Full Text Available The monotonic and cyclic deformation behavior of ultrafine-grained metastable austenitic steel AISI 304L, produced by severe plastic deformation, was investigated. Under monotonic loading, the martensitic phase transformation in the ultrafine-grained state is strongly favored. Under cyclic loading, the martensitic transformation behavior is similar to the coarse-grained condition, but the cyclic stress response is three times larger for the ultrafine-grained condition.

  11. Wear resistance of Fe-Nb-Cr-W, Nb, AISI 1020 and AISI 420 coatings produced by thermal spray wire arc; Resistencia al desgaste de recubrimientos Fe-Nb-Cr-W, Nb, AISI 1020 y AISI 420 producidos por proyeccion termica por arco electrico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Covaleda, E. A.; Mercado-Veladia, J. L.; Olaya-Florez, J. J.

    2013-07-01

    The commercial materials 140MXC (with iron, tungsten, chrome, niobium), 530AS (AISI 1015 steel) and 560AS (AISI 420 steel) on AISI 4340 steel were deposited using thermal spray with arc. The aim of work was to evaluate the best strategy abrasive wear resistance of the system coating-substrate using the following combinations: (1) homogeneous coatings and (2) coatings depositing simultaneously 140MXC + 530AS and 140MXC + 560AS. The coatings microstructure was characterized using Optical microscopy, Scanning electron microscopy and Laser con focal microscopy. The wear resistance was evaluated through dry sand rubber wheel test (DSRW). We found that the wear resistance depends on the quantity of defects and the mechanical properties like hardness. For example, the softer coatings have the biggest wear rates and the failure mode was characterized by plastic deformation caused by particles indentation, and the other hand the failure mode at the harder materials was grooving. The details and wear mechanism of the coatings produced are described in this investigation. (Author)

  12. Influence of the surface finishing on electrochemical corrosion characteristics of AISI 316L stainless steel

    Directory of Open Access Journals (Sweden)

    Sylvia Dundeková

    2015-05-01

    Full Text Available Stainless steels from 316 group are very often and successfully uses for medical applications where the good mechanical and chemical properties in combination with non-toxicity of the material assure its safe and long term usage. Corrosion properties of AISI 361L stainless steel are strongly influenced by surface roughness and treatment of the engineering parts (specimens and testing temperature. Electrochemical characteristics of ground, mechanically polished and passivated AISI 316L stainless steel specimens were examined with the aim to identify the polarization resistance evolution due to the surface roughness decrease. Results obtained on mechanically prepared specimens where only natural oxide layer created due to the exposure of the material to the corrosion environment was protecting the materials were compared to the passivated specimens with artificial oxide layer. Also the influence of temperature and stabilization time before measurement were taken into account when discussing the obtained results. Positive influence of decreasing surface roughness was obtained as well as increase of polarization resistance due to the chemical passivation of the surface. Increase of the testing temperature and short stabilization time of the specimen in the corrosion environment were observed negatively influencing corrosion resistance of AISI 316L stainless steel.

  13. Stoichiometric titanium dioxide ion implantation in AISI 304 stainless steel for corrosion protection

    Science.gov (United States)

    Hartwig, A.; Decker, M.; Klein, O.; Karl, H.

    2015-12-01

    The aim of this study is to evaluate the applicability of highly chemically inert titanium dioxide synthesized by ion beam implantation for corrosion protection of AISI 304 stainless steel in sodium chloride solution. More specifically, the prevention of galvanic corrosion between carbon-fiber reinforced plastic (CFRP) and AISI 304 was investigated. Corrosion performance of TiO2 implanted AISI 304 - examined for different implantation and annealing parameters - is strongly influenced by implantation fluence. Experimental results show that a fluence of 5 × 1016 cm-2 (Ti+) and 1 × 1017 cm-2 (O+) is sufficient to prevent pitting corrosion significantly, while galvanic corrosion with CFRP can already be noticeably reduced by an implantation fluence of 5 × 1015 cm-2 (Ti+) and 1 × 1016 cm-2 (O+). Surface roughness, implantation energy and annealing at 200 °C and 400 °C show only little influence on the corrosion behavior. TEM analysis indicates the existence of stoichiometric TiO2 inside the steel matrix for medium fluences and the formation of a separated metal oxide layer for high fluences.

  14. Application of direct laser metal tooling for AISI H13 tool steel

    Institute of Scientific and Technical Information of China (English)

    Jae-Ho LEE; Jeong-Hwan JANG; Byeong-Don JOO; Hong-Sup YIM; Young-Hoon MOON

    2009-01-01

    In the die industry, it is commonly agreed that residual tool life can be successfully extended by timely repair of damaged surfaces. Traditionally, the main repair process is tungsten inert gas (TIG) welding, but a new process called direct laser metal tooling (DLMT) emerges. DLMT is a manual process, of which results depend on the materials of the powders and tools, the laser process and parameters. This technology is a direct-metal freeform fabrication technique in which a 200 W fiber laser is used. AISI H13 tool steel is a suitable material for die casting tools because of the high resistance to thermal fatigue and dimensional stability. In this research, AISI HI3 tool steel was melted with metal powder by fiber laser. Before melting AISI H13, the powders were analyzed with XRF equipment. Then, hardness distribution of laser melted zone was investigated. The microstructure in laser melted zone was discussed. In order to identify the effect of particle size of powder on the melted zone, two types of particle sizes of powders were used. Experimental results show that the mold repair process using DLMT can be applied in the mold repair industry.

  15. Experimental investigation of wear characteristics on TiCN-coated AISI 410 steel

    Science.gov (United States)

    Prabakaran, Vijayasarathi; Sivakumaran, Ilaiyavel; Palimar, Suresh Prabhu

    2016-04-01

    In this work, the dry sliding wear test of uncoated and multilayer TiCN-coated AISI 410 steel against high carbon steel disc recognized at 2.30267 ms-1 sliding speeds and under a three series load of 5, 10 and 20 N at room temperature. On account of the more coherent interface between TiCN and C probably found, there are high hardness and superior wear resistance. Compared to AISI 410 uncoated steel, the presence of C in the multilayer TiCN coatings leads to reduced coefficient of friction and wear loss. The multilayer TiCN coating is characterized by X-ray diffraction analysis, scanning electron microscopy, micro-hardness and pin-on-disc tribometer tests. The more grooving region, pits and ploughing ridge were examined on the worn surface of the AISI 410 uncoated steel. The result shows hard multilayer TiCN-coated particles viewing on the worn surface of the high carbon steel disc.

  16. Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating

    Science.gov (United States)

    Howard, Stanley R.; Korinko, Paul S.

    2008-05-27

    A method of fabricating a heat exchanger includes brush electroplating plated layers for a brazing alloy onto a stainless steel tube in thin layers, over a nickel strike having a 1.3 .mu.m thickness. The resultant Au-18 In composition may be applied as a first layer of indium, 1.47 .mu.m thick, and a second layer of gold, 2.54 .mu.m thick. The order of plating helps control brazing erosion. Excessive amounts of brazing material are avoided by controlling the electroplating process. The reticulated copper foam rings are interference fit to the stainless steel tube, and in contact with the plated layers. The copper foam rings, the plated layers for brazing alloy, and the stainless steel tube are heated and cooled in a vacuum furnace at controlled rates, forming a bond of the copper foam rings to the stainless steel tube that improves heat transfer between the tube and the copper foam.

  17. MECHANISTIC STUDIES OF IMPROVED FOAM EOR PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    William R. Rossen

    2003-03-31

    The objective of this research is to widen the application of foam to enhanced oil recovery (EOR) by investigating fundamental mechanisms of foams in porous media. This research will lay the groundwork for more applied research on foams for improved sweep efficiency in miscible gas, steam and surfactant-based EOR. Task 1 investigates the pore-scale interactions between foam bubbles and polymer molecules. Task 2 examines the mechanisms of gas trapping, and interaction between gas trapping and foam effectiveness. Task 3 investigates mechanisms of foam generation in porous media. Significant progress was made during this period on all three Tasks. Regarding Task 1, we studied the behavior of foam made without polymer, with low-molecular-weight and high-molecular-weight polyacrylamide, and with xanthan polymer in sandpacks. Results consistently showed that polymer does not stabilize foam in porous media per se. Rather, it destabilizes foam to some extent, but may increase the viscosity of water sufficiently to increase the resistance to flow in spite of the lower intrinsic stability of the foam. This is consistent with the hypothesis the motivated our study. Results also showed that polymer shifts behavior from the high-quality foam-flow regime toward the low-quality regime, consistent with our initial hypothesis. Other aspects of the experimental results were puzzling and are discussed in the text of this report. Research on Task 2 included building an apparatus for gas-phase tracer tests for direct measurement of trapped-gas saturation with foam. We also investigated the nature of the low-quality foam regime, which is thought to be controlled by gas trapping and mobilization. In both the studies of polymers and foam and separate studies of CO{sub 2} foam, we observed behavior that seems to be related to the low-quality regime, but shows unexpected trends: specifically, a decrease in pressure gradient with increasing liquid injection rate, at fixed gas injection rate

  18. New decontamination process using foams containing particles

    Energy Technology Data Exchange (ETDEWEB)

    Guignot, S.; Faure, S. [CEA Marcoule, Lab. des Procedes Avances de Decontamination, 30 (France)

    2008-07-01

    One key point in the dismantling of nuclear facilities is the thorough cleaning of radiation- exposed surfaces on which radioactive deposits have formed. This cleaning step is often achieved by successive liquid rinses with specific solutions containing alkaline, acidic, or even oxidizing species depending on whether the aim is to dissolve greasy deposits (like ter-butylphosphate) or to corrode surfaces on micrometric thicknesses. An alternative process to reduce the amount of chemicals and the volume of the resulting nuclear wastes consists in using the same but foamed solutions (1). Carrying less liquid, the resulting foams still display similar kinetics of dissolution rates and their efficiency is determined by their ability to hold sufficient wetnesses during the time required for the decontamination. Classical foam decontamination process illustrated by foam pulverization or circulation in the 90 turned five years ago into a specific static process using high-lifetime viscosified foam at a steady state. One way to slow down the liquid drainage is to raise liquid viscosity by adding organic viscosifiers like xanthan gum (2). In 2005, new studies started on an innovative process proposed by S. Faure and based on triphasic foams containing particles [3]. The aim is to generate new decontamination foams containing less quantities of organics materials (surfactants and viscosifiers). Silica particles are obviously known to stabilize or destabilize foams (4). In the frame of S. Guignot Ph.D., new fundamental studies are initiated in order to clarify the role of silica solid microparticles in these foams. Our final goal is to determine whether this kind of new foam can be stable for several hours for a decontamination process. The results we will report focus on wet foams used for nuclear decontamination and incorporating fumed silica. The study is conducted on a vertical foam column in a pseudo-free drainage configuration, and aims at investigating the influence of

  19. Detailed investigation of the microbial community in foaming activated sludge reveals novel foam formers.

    Science.gov (United States)

    Guo, Feng; Wang, Zhi-Ping; Yu, Ke; Zhang, T

    2015-01-06

    Foaming of activated sludge (AS) causes adverse impacts on wastewater treatment operation and hygiene. In this study, we investigated the microbial communities of foam, foaming AS and non-foaming AS in a sewage treatment plant via deep-sequencing of the taxonomic marker genes 16S rRNA and mycobacterial rpoB and a metagenomic approach. In addition to Actinobacteria, many genera (e.g., Clostridium XI, Arcobacter, Flavobacterium) were more abundant in the foam than in the AS. On the other hand, deep-sequencing of rpoB did not detect any obligate pathogenic mycobacteria in the foam. We found that unknown factors other than the abundance of Gordonia sp. could determine the foaming process, because abundance of the same species was stable before and after a foaming event over six months. More interestingly, although the dominant Gordonia foam former was the closest with G. amarae, it was identified as an undescribed Gordonia species by referring to the 16S rRNA gene, gyrB and, most convincingly, the reconstructed draft genome from metagenomic reads. Our results, based on metagenomics and deep sequencing, reveal that foams are derived from diverse taxa, which expands previous understanding and provides new insight into the underlying complications of the foaming phenomenon in AS.

  20. Detailed investigation of the microbial community in foaming activated sludge reveals novel foam formers

    Science.gov (United States)

    Guo, Feng; Wang, Zhi-Ping; Yu, Ke; Zhang, T.

    2015-01-01

    Foaming of activated sludge (AS) causes adverse impacts on wastewater treatment operation and hygiene. In this study, we investigated the microbial communities of foam, foaming AS and non-foaming AS in a sewage treatment plant via deep-sequencing of the taxonomic marker genes 16S rRNA and mycobacterial rpoB and a metagenomic approach. In addition to Actinobacteria, many genera (e.g., Clostridium XI, Arcobacter, Flavobacterium) were more abundant in the foam than in the AS. On the other hand, deep-sequencing of rpoB did not detect any obligate pathogenic mycobacteria in the foam. We found that unknown factors other than the abundance of Gordonia sp. could determine the foaming process, because abundance of the same species was stable before and after a foaming event over six months. More interestingly, although the dominant Gordonia foam former was the closest with G. amarae, it was identified as an undescribed Gordonia species by referring to the 16S rRNA gene, gyrB and, most convincingly, the reconstructed draft genome from metagenomic reads. Our results, based on metagenomics and deep sequencing, reveal that foams are derived from diverse taxa, which expands previous understanding and provides new insight into the underlying complications of the foaming phenomenon in AS.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shang, J.T. [Key laboratory of MEMS of Ministry of Education, Southeast University, Nanjing 210096 (China)], E-mail: Jshang@seu.edu.cn; Xuming, Chu; Deping, He [School of Materials Science and Engineering, Southeast University, Nanjing 210096 (China)

    2008-06-25

    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.

  2. Foam drilling in natural gas hydrate

    Directory of Open Access Journals (Sweden)

    Wei Na

    2015-01-01

    Full Text Available The key problem of foam drilling in natural gas hydrate is prediction of characteristic parameters of bottom hole. The simulation shows that when the well depth increases, the foam mass number reduces and the pressure increases. At the same depth, pressure in drill string is always higher than annulus. The research findings provide theoretical basis for safety control.

  3. Development of Steel Foam Materials and Structures

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth Kremer; Anthony Liszkiewicz; James Adkins

    2004-10-20

    In the past few years there has been a growing interest in lightweight metal foams. Demands for weight reduction, improved fuel efficiency, and increased passenger safety in automobiles now has manufacturers seriously considering the use of metal foams, in contrast to a few years ago, when the same materials would have been ruled out for technical or economical reasons. The objective of this program was to advance the development and use of steel foam materials, by demonstrating the advantages of these novel lightweight materials in selected generic applications. Progress was made in defining materials and process parameters; characterization of physical and mechanical properties; and fabrication and testing of generic steel foam-filled shapes with compositions from 2.5 wt.% to 0.7 wt.% carbon. A means of producing steel foam shapes with uniform long range porosity levels of 50 to 60 percent was demonstrated and verified with NDE methods. Steel foam integrated beams, cylinders and plates were mechanically tested and demonstrated advantages in bend stiffness, bend resistance, and crush energy absorption. Methods of joining by welding, adhesive bonding, and mechanical fastening were investigated. It is important to keep in mind that steel foam is a conventional material in an unconventional form. A substantial amount of physical and mechanical properties are presented throughout the report and in a properties database at the end of the report to support designer's in applying steel foam in unconventional ways.

  4. Aqueous foams stabilized by chitin nanocrystals

    NARCIS (Netherlands)

    Tzoumaki, M.; Karefyllakis, D.; Moschakis, T.; Biliaderis, C.G.; Scholten, E.

    2015-01-01

    The aim of the present study was to explore the potential use of chitin nanocrystals, as colloidal rod-like particles, to stabilize aqueous foams. Chitin nanocrystals (ChN) were prepared by acid hydrolysis of crude chitin and foams were generated mainly by sonicating the respective dispersions. The

  5. How carbon nanofibers attach to Ni foam.

    NARCIS (Netherlands)

    Chinthaginjala, J.K.; Thakur, D.B.; Seshan, Kulathuiyer; Lefferts, Leonardus

    2008-01-01

    A stable Carbon-Nano-Fiber (CNF) layer was catalytically grown on Ni foam by decomposing ethylene. Scanning electron microscopy of the cross-section of the deposited layer on Ni foam revealed the presence of two distinct carbon layers; an apparently dense layer (‘C-layer’) at the carbon–Ni interface

  6. Method of foaming a liquid metal

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, A.K.; Johnson, C.E.

    1980-01-15

    The addition of a small quantity of barium to liquid metal NaK or sodium has been found to promote foam formation and improve bubble retention in the liquid metal. A stable liquid metal foam will provide a more homogeneous liquid metal flow through the channel of a two-phase liquid metal MHD power generator to improve operating efficiency.

  7. Method of foaming a liquid metal

    Science.gov (United States)

    Fischer, Albert K.; Johnson, Carl E.

    1980-01-01

    The addition of a small quantity of barium to liquid metal NaK or sodium has been found to promote foam formation and improve bubble retention in the liquid metal. A stable liquid metal foam will provide a more homogeneous liquid metal flow through the channel of a two-phase liquid metal MHD power generator to improve operating efficiency.

  8. Injectivity Errors in Simulation of Foam EOR

    NARCIS (Netherlands)

    Leeftink, T.N.; Latooij, C.A.; Rossen, W.R.

    2013-01-01

    Injectivity is a key factor in the economics of foam EOR processes. Poor injectivity of lowmobility foam slows the production of oil and allows more time for gravity segregation of injected gas. The conventional Peaceman equation, when applied in a large grid block, makes two substantial errors in e

  9. Injectivity errors in simulation of foam EOR

    NARCIS (Netherlands)

    Leeftink, T.N.; Latooij, C.A.; Rossen, W.R.

    2014-01-01

    Injectivity is a key factor in the economics of foam enhanced oil recovery (EOR) processes. Poor injectivity of low-mobility foam slows the production of oil and allows more time for gravity segregation of injected gas. The conventional Peaceman equation (1978), when applied in a large grid block, m

  10. Advanced Processing of Hollow Sphere Foams

    Science.gov (United States)

    2007-11-02

    composition is close to that of 405 stainless. Carburization in CO/CO2 atmosphere followed by heat treatment produces foams of either 410 or 420 type...after carburization . A sample with 0.5 wt% carbon at a relative density of 15% indicated a yield strength of 16 MPa. Specific strengths of the foams were

  11. New views on foams from protein solutions

    NARCIS (Netherlands)

    Wierenga, P.A.; Gruppen, H.

    2010-01-01

    The stabilization of foam by proteins has been mostly studied in relation to the food industry. The main aim of the research is to understand the relation between proteins used and the product properties. The molecular properties of proteins and their foam forming and stabilizing properties are typi

  12. Drag Coefficient and Foam in Hurricane Conditions.

    Science.gov (United States)

    Golbraikh, E.; Shtemler, Y.

    2016-12-01

    he present study is motivated by recent findings of saturation and even decrease in the drag coefficient (capping) in hurricane conditions, which is accompanied by the production of a foam layer on the ocean surface. As it is difficult to expect at present a comprehensive numerical modeling of the drag coefficient saturation that is followed by wave breaking and foam production, there is no complete confidence and understanding of the saturation phenomenon. Our semi-empirical model is proposed for the estimation of the foam impact on the variation of the effective drag coefficient, Cd , with the reference wind speed U10 in stormy and hurricane conditions. The proposed model treats the efficient air-sea aerodynamic roughness length as a sum of two weighted aerodynamic roughness lengths for the foam-free and foam-covered conditions. On the available optical and radiometric measurements of the fractional foam coverage,αf, combined with direct wind speed measurements in hurricane conditions, which provide the minimum of the effective drag coefficient, Cd for the sea covered with foam. The present model yields Cd10 versus U10 in fair agreement with that evaluated from both open-ocean and laboratory measurements of the vertical variation of mean wind speed in the range of U10 from low to hurricane speeds. The present approach opens opportunities for drag coefficient modeling in hurricane conditions and hurricane intensity estimation by the foam-coverage value using optical and radiometric measurements.

  13. Expanded polylactide bead foaming - A new technology

    Science.gov (United States)

    Nofar, M.; Ameli, A.; Park, C. B.

    2015-05-01

    Bead foaming technology with double crystal melting peak structure has been recognized as a promising method to produce low-density foams with complex geometries. During the molding stage of the bead foams, the double peak structure generates a strong bead-to-bead sintering and maintains the overall foam structure. During recent years, polylactide (PLA) bead foaming has been of the great interest of researchers due to its origin from renewable resources and biodegradability. However, due to the PLA's low melt strength and slow crystallization kinetics, the attempts have been limited to the manufacturing methods used for expanded polystyrene. In this study, for the first time, we developed microcellular PLA bead foams with double crystal melting peak structure. Microcellular PLA bead foams were produced with expansion ratios and average cell sizes ranging from 3 to 30-times and 350 nm to 15 µm, respectively. The generated high melting temperature crystals during the saturation significantly affected the expansion ratio and cell density of the PLA bead foams by enhancing the PLA's poor melt strength and promoting heterogeneous cell nucleation around the crystals.

  14. Anti-foam System design description

    Energy Technology Data Exchange (ETDEWEB)

    White, M.A.

    1994-09-30

    The Anti-foam System is a sub-system of the 242-A Evaporator facility. The Anti-foam is used within the C-A-1 Vapor-Liquid Separator, to reduce the effect of foaming and reduce fluid bumping while the vapor and liquid are separated within the C-A-1 Vapor-Liquid Separator. Excessive foaming within the vessel may possibly cause the liquid slurry mixture in the evaporator vessel to foul the de-entrainment pads and cause plant shutdown. The Anti-foam System consists of the following primary elements: the Anti-foam Tank and the Metering Pump. The upgrades to Anti-foam System include the following: installation of a new pump, instruments, and valves; and connection of the instruments, pump and agitator associated with the Anti-foam System to the Monitoring and Control System (MCS). The 242-A Evaporator is a waste treatment facility designed to reduce liquid waste volumes currently stored in the Hanford Area double shell Waste Storage Tanks. The evaporator uses evaporative concentration to achieve this volume reduction, returning the concentrated slurry to the double-shell tanks for storage and, at the same time, releasing the process effluent to a retention facilities for eventual treatment and release to the environment.

  15. Low-density, polymer foams as structural models for phase-separation in polymer solutions

    Energy Technology Data Exchange (ETDEWEB)

    Beaucage, G. [Univ. of Cincinnati, OH (United States); Lagasse, R.R.; Aubert, J.H. [Sandia National Labs., Albuquerque, NM (United States)] [and others

    1995-12-31

    Low density polymer foams are produced through nano-scale phase separation of 5 to 15% solutions yielding gels. The gels are solvent exchanged and dried by supercritical extraction. We have found that the morphology of the phase separated gel, the intermediate solvent exchanged gels and the final foams are essentially identical over a wide range of size. Through the combination of several scattering techniques covering many decades of size we can distinguish structural levels in these low-density foams. The combined scattering data spans sizes ranging from 10{mu}m to 1{Angstrom}. A recently developed global fitting approach can describe the multiple levels of structure observed in these complex materials. Several morphological classes of foams are observed. A perplexing feature in the scattering patterns from all of the foams is a 3-dimensional structure with a radius of gyration from 40 to 100{Angstrom}. By variation of the polymer molecular-weight, scattering data supports a model describing this nano-scale structure as partially isolated, collapsed polymer coils. This model indicates that collapsed base structural unit in these morphologies.

  16. Engineered carbon foam for temperature control applications

    Science.gov (United States)

    Almajali, Mohammad Rajab

    The need for advanced thermal management materials is well recognized in the electronics and communication industries. An overall reduction in size of electronic components has lead to higher power dissipation and increased the necessity for innovative cooling designs. In response, material suppliers have developed and are continuing to develop, an increasing number of light weight thermal management materials. The new carbon foam is a low density and high thermal conductivity material which has the potential to radically improve heat transfer, thereby reducing size and weight of equipment while simultaneously increasing its efficiency and capabilities. However, carbon foam exhibits low strength and low heat capacity. The present work is intended to overcome these two main drawbacks using a combinatorial approach: (i) initially, copper coating was carried out to improve the thermo-mechanical properties of carbon foam. The thermal and mechanical properties of coated foam were measured using laser flash technique and compression test, respectively. An analytical model was developed to calculate the effective thermal conductivity. It was observed that the copper-coated carbon foam with 50% porosity can attain a thermal conductivity of 180 W/mK. The results from the analytical model were in a very good agreement with experimental results. The modulus increased from 4.5 MPa to 8.6 MPa and the plateau stress increased from 54 kPa to 171 kPa. The relationships between the measured properties and the copper weight ratio were determined. The above analyses demonstrated the significance of copper coating in tailoring carbon foam properties. (ii) Numerical and experimental studies were performed to analyze the phase change behavior of wax/foam composite encapsulated in metal casing. A two-energy equation model was solved using computational fluid dynamics software (CFD). Interfacial effects at the casing-composite junction and between the wax-foam surfaces and the capillary

  17. Cells on foam and fiber

    Energy Technology Data Exchange (ETDEWEB)

    Clyde, R. [Clyde Engineering, New Orleans, LA (United States)

    1995-11-01

    Cells growing on high area foam and when a screen is put around the foam, it is made heavier so it can be fluidized. When foam is rotated in a half full RBC, drops are formed and mass transfer of oxygen to drops in much faster. Most fungi and some mammalian cells need oxygen. Corrugated fibers with holes in the valleys also produce drops. White rot fungus needs oxygen and it degrades many chlorine compounds, azo dyes, and TNT. Old cardboard boxes are readily available and when buried in soil, oxygen is entrapped. In a lake, the boxes expose high area. Fibers have high surface area for immobilizing cells and when the fibers are rotated, fast reactions occur, converting one chemical to another. Sugar has been fermented to alcohol in 10-15 minutes. Ethanol has high octane and does not need lead. Old cars and trucks still use lead and high levels have been found in the drinking water of several large cities. Bacteria on fibers can remove lead in a few seconds. When an RBC of plain fiber discs is rotated and a light shone in the top the light hits a thin moving film to degrade chlorine compounds. Microbes and light remove sulfur from oil. Calcium magnesium acetate is a non corrosive road deicer. Salt on roads causes millions of dollars damage to bridges and cars. An inexpensive reactor has been made for organization studies of mammalian and plant cells. A magnet is near the bottom but not touching and oxygen is put on the top where there is no seal that can leak.

  18. Biodegradable foam plastics based on castor oil.

    Science.gov (United States)

    Wang, Hong Juan; Rong, Min Zhi; Zhang, Ming Qiu; Hu, Jing; Chen, Hui Wen; Czigány, Tibor

    2008-02-01

    In this work, a simple but effective approach was proposed for preparing biodegradable plastic foams with a high content of castor oil. First of all, castor oil reacted with maleic anhydride to produce maleated castor oil (MACO) without the aid of any catalyst. Then plastic foams were synthesized through free radical initiated copolymerization between MACO and diluent monomer styrene. With changes in MACO/St ratio and species of curing initiator, mechanical properties of MACO foams can be easily adjusted. In this way, biofoams with comparable compressive stress at 25% strain as commercial polyurethane (PU) foams were prepared, while the content of castor oil can be as high as 61 wt %. The soil burial tests further proved that the castor oil based foams kept the biodegradability of renewable resources despite the fact that some petrol-based components were introduced.

  19. Surfactant recovery from water using foam fractionation

    Energy Technology Data Exchange (ETDEWEB)

    Tharapiwattananon, N.; Osuwan, S. [Chulalongkorn Univ., Bangkok (Thailand); Scamehorn, J.F. [Inst. of Oklahoma, Norman, OK (United States)] [and others

    1996-05-01

    The purpose of this study was to investigate the use of foam fractionation to recover surfactant from water. A simple continuous mode foam fractionation was used and three surfactants were studied (two anionic and one cationic). The effects of air flow rate, foam height, liquid height, liquid feed surfactant concentration, and sparger porosity were studied. This technique was shown to be effective in either surfactant recovery or the reduction of surfactant concentration in water to acceptable levels. As an example of the effectiveness of this technique, the cetylpyridinium chloride concentration in water can be reduced by 90% in one stage with a liquid residence time of 375 minutes. The surfactant concentration in the collapsed foam is 21.5 times the feed concentration. This cationic surfactant was easier to remove from water by foam fractionation than the anionic surfactants studied.

  20. Modeling Decomposition of Unconfined Rigid Polyurethane Foam

    Energy Technology Data Exchange (ETDEWEB)

    HOBBS,MICHAEL L.; ERICKSON,KENNETH L.; CHU,TZE YAO

    1999-11-08

    The decomposition of unconfined rigid polyurethane foam has been modeled by a kinetic bond-breaking scheme describing degradation of a primary polymer and formation of a thermally stable secondary polymer. The bond-breaking scheme is resolved using percolation theory to describe evolving polymer fragments. The polymer fragments vaporize according to individual vapor pressures. Kinetic parameters for the model were obtained from Thermal Gravimetric Analysis (TGA). The chemical structure of the foam was determined from the preparation techniques and ingredients used to synthesize the foam. Scale-up effects were investigated by simulating the response of an incident heat flux of 25 W/cm{sup 2} on a partially confined 8.8-cm diameter by 15-cm long right circular cylinder of foam that contained an encapsulated component. Predictions of center, midradial, and component temperatures, as well as regression of the foam surface, were in agreement with measurements using thermocouples and X-ray imaging.

  1. Modeling Decomposition of Unconfined Rigid Polyurethane Foam

    Energy Technology Data Exchange (ETDEWEB)

    CHU,TZE YAO; ERICKSON,KENNETH L.; HOBBS,MICHAEL L.

    1999-11-01

    The decomposition of unconfined rigid polyurethane foam has been modeled by a kinetic bond-breaking scheme describing degradation of a primary polymer and formation of a thermally stable secondary polymer. The bond-breaking scheme is resolved using percolation theory to describe evolving polymer fragments. The polymer fragments vaporize according to individual vapor pressures. Kinetic parameters for the model were obtained from Thermal Gravimetric Analysis (TGA). The chemical structure of the foam was determined from the preparation techniques and ingredients used to synthesize the foam. Scale-up effects were investigated by simulating the response of an incident heat flux of 25 W/cm{sup 2} on a partially confined 8.8-cm diameter by 15-cm long right circular cylinder of foam which contained an encapsulated component. Predictions of center, midradial, and component temperatures, as well as regression of the foam surface, were in agreement with measurements using thermocouples and X-ray imaging.

  2. Method to evaluate foaming in petroleum

    Energy Technology Data Exchange (ETDEWEB)

    Fraga, A.K.; Rezende, D.A.; Santos, R.F.; Mansur, C.R.E. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Macromoleculas], e-mail: celias@ima.ufrj.br

    2011-01-15

    In oil fields, gravitational separation tanks are generally used to separate the oil, gas and water phases, remove emulsifying agents present at the interfaces and permit the coalescence of water droplets associated with the crude oil being pumped. The main problem that influences the performance of these separators is the formation of foam. In this work, a method was developed to evaluate foaming in crude oil in laboratory scale, reproducing the operation conditions in gas-oil separators in real fields. This method was employed with seven crude oil samples, and the performance of silicone anti foams with different molar masses could be tested. The results indicated that the method of evaluating the breakdown of foam in oil by using the Aging Cell apparatus in a roller oven proved to be suitable. It was observed that the oil viscosity is a determining factor in predicting whether or not foam will form. (author)

  3. Autoclave foam concrete: Structure and properties

    Science.gov (United States)

    Mestnikov, Alexei; Semenov, Semen; Strokova, Valeria; Nelubova, Viktoria

    2016-01-01

    This paper describes the technology and properties of autoclaved foam concrete taking into account practical experience and laboratory studies. The results of study of raw materials and analysis of structure and properties of foam-concrete before and after autoclave treatment are basic in this work. Experimental studies of structure and properties of foam concrete are carried out according to up-to-date methods and equipment on the base of the shared knowledge centers. Results of experimental studies give a deep understanding of properties of raw materials, possible changes and new formations in inner layers of porous material providing the improvement of constructional and operational properties of autoclaved foam concrete. Principal directions of technology enhancement as well as developing of production of autoclave foam concretes under cold-weather conditions in Russia climate are justified.

  4. Evaluation of performance of AISI 444 steel for application in distillation towers; Avaliacao do desempenho do aco AISI 444 para aplicacao como 'lining' em torres de destilacao

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, R.F.; Miranda, H.C. de; Farias, J.P. [Universidade Federal do Ceara (DEMM/UFC), Fortaleza, CE (Brazil). Dept. de Engenharia Metalurgica e de Materiais. Lab. de Caracterizacao de Materiais], e-mail: rf.guimaraes@yahoo.com.br

    2008-07-01

    In this work, the behavior of the AISI 444 ferritic stainless steel submitted to thermal fatigue test and their corrosion resistance in heavy crude oil was evaluated. The AWS E309MoL-16 and E316L-17 weld metal was employed as filler metal. Plates of the AISI 444 were welded on ASTM A-516 Gr. 60 plates and submitted to fatigue thermal cycle. Samples were extracted from plates welded and heat treated immersed in heavy crude oil at 300 deg C. Optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive of X-ray analysis (EDX) were used to characterize the microstructure and the corroded surface. The results show that the AISI 444 stainless steels did not present cracks after the thermal fatigue cycle and the heat treated immerse in heavy crude oil. The electrode AWS E309MoL-16 show better corrosion resistance than the AWS E316L-17. (author)

  5. Carbon particle induced foaming of molten sucrose for the preparation of carbon foams

    Energy Technology Data Exchange (ETDEWEB)

    Narasimman, R.; Vijayan, Sujith; Prabhakaran, K., E-mail: kp2952002@gmail.com

    2014-11-15

    Graphical abstract: - Highlights: • An easy method for the preparation of carbon foam from sucrose is presented. • Wood derived activated carbon particles are used to stabilize the molten sucrose foam. • The carbon foams show relatively good mechanical strength. • The carbon foams show excellent CO{sub 2} adsorption and oil absorption properties. • The process could be scaled up for the preparation of large foam bodies. - Abstract: Activated carbon powder was used as a foaming and foam setting agent for the preparation of carbon foams with a hierarchical pore structure from molten sucrose. The rheological measurements revealed the interruption of intermolecular hydrogen bonding in molten sucrose by the carbon particles. The carbon particles stabilized the bubbles in molten sucrose by adsorbing on the molten sucrose–gas interface. The carbon foams obtained at the activated carbon powder to sucrose weight ratios in the range of 0–0.25 had a compressive strength in the range of 1.35–0.31 MPa. The produced carbon foams adsorb 2.59–3.04 mmol/g of CO{sub 2} at 760 mmHg at 273 K and absorb oil from oil–water mixtures and surfactant stabilized oil-in-water emulsions with very good selectivity and recyclability.

  6. Fracture of open- and closed-cell metal foams

    NARCIS (Netherlands)

    Onck, P; van Merkerk, R.; Raaijmakers, A; De Hosson, JTM

    2005-01-01

    Two closed cell aluminium foams and one open cell nickel-chromium foam were subjected to microstructural characterization, in situ fracture tests and fractography. The failure process of the open cell foam was observed to be rather ductile, while that of the closed cell foams was found to be brittle

  7. Fracture of open- and closed-cell metal foams

    NARCIS (Netherlands)

    Onck, P; van Merkerk, R.; Raaijmakers, A; De Hosson, JTM

    2005-01-01

    Two closed cell aluminium foams and one open cell nickel-chromium foam were subjected to microstructural characterization, in situ fracture tests and fractography. The failure process of the open cell foam was observed to be rather ductile, while that of the closed cell foams was found to be

  8. Foam stabilization by solid particle aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Guignot, S.; Faure, S. [CEA Marcoule, Lab. des Procedes Avances de Decontamination, 30 (France); Pitois, O. [UniversiteParis-Est Marne-La-Valle, Lab. Physique des Materiaux Divises et des Interfaces (LPMDI), 77 - Marne la Vallee (France)

    2008-07-01

    During the dismantling of nuclear facilities, radioactive deposits on exposed areas are removed and solubilized by successive rinses of reactive liquid. Using this liquid in a foam state reduces the amount of resulting wastes. During the required decontamination time (1 to 5 hours) the foam has to be sufficiently wet (1). In the Laboratory of Advanced Processes for Decontamination, new formulations are currently studied to slow down the drainage kinetics of these foams, by adding colloidal particles of hydrophilic fumed silica into the classical mixtures of well-defined non ionic foaming surfactants previously used (2). The objective of our study is to shed light on the foam surprising stability induced by these particles. The study focuses on drainage of foams generated by air sparging through a suspension lying on a porous glass. The foaming suspensions contain between 0 and 70 g.L-1 of a fumed silica (Aerosil 380) which is well-known to form gels for concentrations above 200 g.L{sup -1}. In the studied solutions this silica builds up into aggregates of dozens of microns, whose volume-averaged mean diameter after sonication is centred around 300 nm. Under gentle stirring, they display no sign of re-aggregation during 24 h. On a free drainage configuration, a foam that contains particles keeps a significant amount of its initial liquid: up to 60 % during up to 5 hours, in contrast to classical foams that drain out all of their liquid in about 20 minutes. From a rheological point of view, the most concentrated suspensions display a yield stress behaviour. This evidences the structuring of the aggregates into a coherent network that might explain the incomplete drainage of the solutions. For the lowest concentrated solutions, such rheological properties have not been observed although the corresponding foams can retain large amount of solution. This suggests that local concentrations of aggregates can rise owing to their retention by foam channels, until they form

  9. USING BIOPOLYMERS TO STABILIZE THE PROTEIN OXYGEN FOAM

    Directory of Open Access Journals (Sweden)

    N. V. Nepovinnyh

    2013-01-01

    Full Text Available The cottage cheese whey as an oxygen cocktail foaming base and natural juices as a flavoring ingredient are analyzed. The lifetime of foam generated by the serum proteins is not long: foam falls off rapidly; because from the foam liquid is released (syneresis. The effects of plant polysaccharides on the stabilization of the protein foam oxygen cocktail is studied. It was shown that the use of plant polysaccharides (guar gum, high methoxyl citrus pectin, locust been gum prolong the life of the foam up to 20 times, compared with conventional blowing agents. It was found that oxygen foam properties depend on the molecular weight of guar gum.

  10. Metal Foaming Investigated by X-ray Radioscopy

    Directory of Open Access Journals (Sweden)

    Catalina Jiménez

    2011-12-01

    Full Text Available The use of X-ray radioscopy for in-situ studies of metal foam formation and evolution is reviewed. Selected results demonstrate the power of X-ray radioscopy as diagnostic tool for metal foaming. Qualitative analyses of foam nucleation and evolution, drainage development, issues of thermal contact, mold filling, cell wall rupture and more are given. Additionally, quantitative analyses based on series of images of foam expansion yielding coalescence rates, density distributions, etc., are performed by dedicated software. These techniques help us to understand the foaming behavior of metals and to improve both foaming methods and foam quality.

  11. ZrP nanoplates based fire-fighting foams stabilizer

    Science.gov (United States)

    Zhang, Lecheng; Cheng, Zhengdong; Li, Hai

    2015-03-01

    Firefighting foam, as a significant innovation in fire protection, greatly facilitates extinguishments for liquid pool fire. Recently, with developments in LNG industry, high-expansion firefighting foams are also used for extinguishing LNG fire or mitigating LNG leakage. Foam stabilizer, an ingredient in fire-fighting foam, stabilizes foam bubbles and maintains desired foam volume. Conventional foam stabilizers are organic molecules. In this work, we developed a inorganic based ZrP (Zr(HPO4)2 .H2O, Zirconium phosphate) plates functionalized as firefighting foam stabilizer, improving firefighting foam performance under harsh conditions. Several tests were conducted to illustrate performance. The mechanism for the foam stabilization is also proposed. Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA. Mary Kay O'Connor Process Safety Center, Texas A&M University, College Station, TX, 77843-3122

  12. Energy absorbing efficiency of various aluminum foam filled tube

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jin Man; Lee, Won Sik; Ko, Se Hyun [Korea Institute of Industrial Technology, Chonan (Korea, Republic of)

    2005-04-15

    In this study various types of A1 foam filled tubes were fabricated using foam of A1-12wt.%Si by powder metallurgical process. Their energy absorbing efficiencies were investigated with compression test, focusing on the structure and bonding effects between tube and foam. The results show that the energy absorption is affected by structure of A1 foam filled tube. Among fully foam filled tube, partially foam filled tube and A1 hollow tube with the same weight, fully foam filled tube seems to have superior potential for industrial application to energy absorption parts. Also energy absorption efficiency is increased by interaction between tube and foam and especially, bonding between tube and metallic foam gives rise to increase the energy absorption efficiency up to above 1.2 times. This results from the arrest of folding of tube by metallic foam and the change of stress mode from uni-axial to multi-axial during compression.

  13. Wear Evaluation of AISI 4140 Alloy Steel with WC/C Lamellar Coatings Sliding Against EN 8 Using Taguchi Method

    Science.gov (United States)

    Kadam, Nikhil Rajendra; Karthikeyan, Ganesarethinam

    2016-10-01

    The purpose of the experiments in this paper is to use the Taguchi methods to investigate the wear of WC/C coated nitrided AISI 4140 alloy steel. A study of lamellar WC/C coating which were deposited by a physical vapor deposition on nitrided AISI 4140 alloy steel. The investigation includes wear evaluation using Pin-on-disk configuration. When WC/C coated AISI 4140 alloy steel slides against EN 8 steel, it was found that carbon-rich coatings show much lower wear of the countersurface than nitrogen-rich coatings. The results were correlated with the properties determined from tribological and mechanical characterization, therefore by probably selecting the proper processing parameters the deposition of WC/C coating results in decreasing the wear rate of the substrate which shows a potential for tribological application.

  14. Preparation of high-performance ultrafine-grained AISI 304L stainless steel under high temperature and pressure

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2016-08-01

    Full Text Available Bulk ultra-fine grained (UFG AISI 304L stainless steel with excellent mechanical properties was prepared by a high-temperature and high-pressure (HTHP method using nanocrystalline AISI 304L stainless steel powders obtained from ball milling. Samples were sintered in high-pressure conditions using the highest martensite content of AISI 304L stainless steel powders milled for 25 h. Analyses of phase composition and grain size were accomplished by X-ray diffraction and Rietveld refinement. By comparing the reverse martensite transformation under vacuum and HTHP treat, we consider that pressure can effectively promote the change in the process of transformation. Compared with the solid-solution-treated 304L, the hardness and yield strength of the samples sintered under HTHP are considerably higher. This method of preparation of UFG bulk stainless steel may be widely popularised and used to obtain UFG metallic materials with good comprehensive performance.

  15. Corrosion Inhibition of AISI 316L and Modified-AISI 630 Stainless Steel by the New Organic Inhibitor [(CH32N]3PSe in Chloride Media:Electrochemical and Physical Study

    Directory of Open Access Journals (Sweden)

    Yafa ZARGOUNI

    2015-04-01

    Full Text Available We evaluate the effect of the Tris-dimethylaminoselenophosphoramide (SeAPon the corrosion inhibition of modified-AISI 630 and AISI 316L stainless steel (SS in 3 wt. % NaCl. The electrochemical behaviors of tested SS samples are investigated before and after adding the Seep into the chloride media by potentiodynamic polarization technique. The adsorption of SeAP onto both SS surfaces is verified by global discharge optical emission spectroscopy (GDOES.  SeAP is found to be a good inhibitor for SS corrosion, especially when added at a concentration of 0.5 wt. %.

  16. Carburizing plasma in a low temperature austenitic stainless steel AISI 304; Cementacao a plasma em baixa temperatura de um aco inoxidavel austenitico AISI 304

    Energy Technology Data Exchange (ETDEWEB)

    Mota, W.T.; Ramos, F.D.; Rocha, R.C.; Barcelos, M.V.; Barcelos, M.A., E-mail: welber.tmota@gmail.com [Instituto Federal do Espirito Santo (IFES), ES (Brazil)

    2014-07-01

    The industrial use of thermochemical treatment assisted by the cold plasma has been widely employed in recent years, mainly oriented to the excellent results obtained in the surface modification of engineering materials, when compared to more traditional methods. In this work, we studied the plasma carburizing low temperature steel AISI 304 mechanical parts used in construction. The thermochemical treatment was performed at a fixed gas atmosphere 7% CH{sub 4} (g) and 93 % H{sub 2} (g), 350 ° C and times of 1, 3 and 5 hours. Samples being tested for Vickers hardness, abrasive microwear, microstructure evaluation by optical microscopy and SEM and X-ray diffraction. The results show significant improvement in surface hardness, wear resistance and good formation of expanded austenite layer and no identifiers peaks of carbides. The results achieved are due to diffusion/adsorption of carbon present in the gaseous atmosphere to the evaluated samples. (author)

  17. Modification and characterization of the AISI 410 martensitic stainless steels surface; Modificacao e caracterizacao da superficie do aco inoxidavel martensitico AISI 410

    Energy Technology Data Exchange (ETDEWEB)

    Bincoleto, A.V.L. [Universidade Federal de Sao Carlos (PPG-CEM/UFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Nascente, P.A.P. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    Steam turbines are used in the generation of more than half the electric energy produced in the world nowadays. It is important the study which aims to improve the efficiency by means of the optimization of leaks and of the aerodynamic profiles, as well as to maintain the integrity of the components. The martensitic stainless steels are widely employed due to the combination of their good mechanical properties with higher corrosion resistance. However, their lower wear resistance and their poor tribological behavior limit their use, since they decrease the component life time. In order to evaluate the improvement in the performance of the AISI 410 stainless steel, several process of surface modification were employed. Five samples were produced: the first one was not treated, the second one received liquid nitriding, the third, gas nitriding, the forth, thermal aspersion of tungsten carbide, and the fifth, boronizing. The samples were characterized by optical microscopy, surface microhardness, and X-ray diffractometry. (author)

  18. 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.

  19. Damping of liquid sloshing by foams

    CERN Document Server

    Sauret, Alban; Cappello, Jean; Dressaire, Emilie; Stone, Howard A

    2014-01-01

    When a container is set in motion, the free surface of the liquid starts to oscillate or slosh. Such effects can be observed when a glass of wa ter is handled carelessly and the fluid sloshes or even spills over the rims of the container. However, beer does not slosh as readily as water, wh ich suggests that foam could be used to damp sloshing. In this work, we study experimentally the effect on sloshing of a liquid foam placed on top of a liquid bath. We generate a monodisperse two-dimensional liquid foam in a rectangular container and track the motion of the foam. The influence of the foam on the sloshing dynamics is experimentally characterized: only a few layers of bubbles are sufficient to significantly damp the oscill ations. We rationalize our experimental findings with a model that describes the foam contribution to the damping coefficient through viscous dissi pation on the walls of the container. Then we extend our study to confined three-dimensional liquid foam and observe that the behavior of 2D a...

  20. Drainage and Stratification Kinetics of Foam Films

    Science.gov (United States)

    Zhang, Yiran; Sharma, Vivek

    2014-03-01

    Baking bread, brewing cappuccino, pouring beer, washing dishes, shaving, shampooing, whipping eggs and blowing bubbles all involve creation of aqueous foam films. Foam lifetime, drainage kinetics and stability are strongly influenced by surfactant type (ionic vs non-ionic), and added proteins, particles or polymers modify typical responses. The rate at which fluid drains out from a foam film, i.e. drainage kinetics, is determined in the last stages primarily by molecular interactions and capillarity. Interestingly, for certain low molecular weight surfactants, colloids and polyelectrolyte-surfactant mixtures, a layered ordering of molecules, micelles or particles inside the foam films leads to a stepwise thinning phenomena called stratification. Though stratification is observed in many confined systems including foam films containing particles or polyelectrolytes, films containing globular proteins seem not to show this behavior. Using a Scheludko-type cell, we experimentally study the drainage and stratification kinetics of horizontal foam films formed by protein-surfactant mixtures, and carefully determine how the presence of proteins influences the hydrodynamics and thermodynamics of foam films.

  1. Feynman diagrammatic approach to spin foams

    CERN Document Server

    Kisielowski, Marcin; Puchta, Jacek

    2011-01-01

    "The Spin Foams for People Without the 3d/4d Imagination" could be an alternative title of our work. We derive spin foams from operator spin network diagrams} we introduce. Our diagrams are the spin network analogy of the Feynman diagrams. Their framework is compatible with the framework of Loop Quantum Gravity. For every operator spin network diagram we construct a corresponding operator spin foam. Admitting all the spin networks of LQG and all possible diagrams leads to a clearly defined large class of operator spin foams. In this way our framework provides a proposal for a class of 2-cell complexes that should be used in the spin foam theories of LQG. Within this class, our diagrams are just equivalent to the spin foams. The advantage, however, in the diagram framework is, that it is self contained, all the amplitudes can be calculated directly from the diagrams without explicit visualization of the corresponding spin foams. The spin network diagram operators and amplitudes are consistently defined on thei...

  2. Foam-on-Tile Damage Model

    Science.gov (United States)

    Koharchik, Michael; Murphy, Lindsay; Parker, Paul

    2012-01-01

    An impact model was developed to predict how three specific foam types would damage the Space Shuttle Orbiter insulating tiles. The inputs needed for the model are the foam type, the foam mass, the foam impact velocity, the foam impact incident angle, the type being impacted, and whether the tile is new or aged (has flown at least one mission). The model will determine if the foam impact will cause damage to the tile. If it can cause damage, the model will output the damage cavity dimensions (length, depth, entry angle, exit angle, and sidewall angles). It makes the calculations as soon as the inputs are entered (less than 1 second). The model allows for the rapid calculation of numerous scenarios in a short time. The model was developed from engineering principles coupled with significant impact testing (over 800 foam impact tests). This model is applicable to masses ranging from 0.0002 up to 0.4 pound (0.09 up to 181 g). A prior tool performed a similar function, but was limited to the assessment of a small range of masses and did not have the large test database for verification. In addition, the prior model did not provide outputs of the cavity damage length, entry angle, exit angle, or sidewall angles.

  3. TEPIC -- A new high temperature structural foam

    Energy Technology Data Exchange (ETDEWEB)

    L. L. Whinnery; S. H. Goods; M. L. Tootle; C. L. Neuschwanger

    1998-10-01

    The formulation, processing characteristics, microstructure and mechanical properties of a new structural foam, suitable for use at service temperatures up to 200 C, are reported. In each of these respects, the foam is compared to an existing material, called APO-BMI that is currently in use. When these two foams are directly compared, the new foam, called TEPIC, is found to be superior in its mechanical performance. TEPIC is formulated from a non-carcinogenic isocyanate, a di-functional epoxide, and glass microballoons. The authors' approach was to combine chemistries known to form thermally stable products. The principal polymerization products are an oxizolidinone produced by the reaction of the isocyanate with the epoxide and isocyanurate rings formed by the trimerization of the isocyanate. Processing has been examined and large-scale production is discussed in detail. Compared to APO-BMI processing, TEPIC processing is facile and economical. The structure of the foam resembles a traditional rigid polyurethane foam rather than that of the APO-BMI. That is, the foam is comprised of a continuous resin phase rather than weakly bonded glass microballoons. At a density of 0.42 g/cm{sup 3} or greater, maximum pore size in TEPIC was less than 2 mm, as required for the application.

  4. Fabrication of superhydrophobic film by microcellular plastic foaming method

    Science.gov (United States)

    Zhang, Zhen Xiu; Li, Ya Nan; Xia, Lin; Ma, Zhen Guo; Xin, Zhen Xiang; Kim, Jin Kuk

    2014-08-01

    To solve the complicated manufacturing operation and the usage of toxic solvent problems, a simple and novel method to fabricate superhydrophobic film by surface foaming method was introduced in this paper. The superhydrophobic property of the foamed material was obtained at a contact angle >150° and a rolling angle about 8°. The foamed material can instantly generate its superhydrophobicity via peeling process. The effects of blowing agent content, foaming time and peeling rate on the foam structure and superhydrophobicity were studied.

  5. Numerical-experimental analysis of a rin AISI{sub 7}Mg Alloy; Analisis numerico experimental de un rin de aleacion AISi{sub 7}Mg

    Energy Technology Data Exchange (ETDEWEB)

    Sauceda Mesa, Israel; Mata Lucero, Omar; Tirado Delgado, Luis; Ocampo Diaz, Juan de Dios [Universidad Autonoma de Baja California, Mexicali, Baja California (Mexico)

    2005-10-15

    The present work shows the results obtained from an investigation mode on the behaviour of a rin of alloy AISi{sub 7}Mg, which is used in compact Volkswagen's cars. Due to two kind of analysis were realized, firstly an experimental and numerical analysis was done, using a special machine for test the flexionante torque and material fatigue, besides was used an equipment of laser to scanner zone with strength concentrations and the maximum displacement amplitudes. The second analysis was done with the finite element technique, using the software ANSYS and CATIA. The difference between life fatigue cycles obtained from the two analyses was 0.6%. While the time optimize by MEF, was of 85% less than experimental analysis. [Spanish] En el presente trabajo se hicieron investigaciones del comportamiento de un rin de aleacion AISi{sub 7}Mg, el cual es usado en automoviles compactos de volkswagen (VW). Para esto, se realizo analisis experimental y numerico. En el primero se utilizo una maquina para prueba de fatiga de momento flexionante, un equipo de medicion de laser escaner donde se detectaron las zonas de concentraciones de esfuerzos y la maxima amplitud de desplazamiento en el rin. Mientras que en el segundo se obtuvieron los esfuerzos que ocasionaban la fatiga por el elemento finito, utilizando los paquetes de computo Ansys y Catia. La diferencia de los ciclos de vida de fatiga obtenidos entre ambos analisis fue del 0.6%. Mientras que el tiempo que se optimizo por el MEF, fue de un 85% menos que el analisis experimental.

  6. Frog Foam Nest Protein Diversity and Synthesis.

    Science.gov (United States)

    Hissa, Denise Cavalcante; Bezerra, Walderly Melgaço; Freitas, Cléverson Diniz Teixeira De; Ramos, Márcio Viana; Lopes, José Luiz De Souza; Beltramini, Leila Maria; Roberto, Igor Joventino; Cascon, Paulo; Melo, Vânia Maria Maciel

    2016-08-01

    Some amphibian species have developed a breeding strategy in which they deposit their eggs in stable foam nests to protect their eggs and larvae. The frog foam nests are rich in proteins (ranaspumin), especially surfactant proteins, involved in the production of the foam nest. Despite the ecological importance of the foam nests for evolution and species conservation, the biochemical composition, the long-term stability and even the origin of the components are still not completely understood. Recently we showed that Lv-RSN-1, a 23.5-kDa surfactant protein isolated from the nest of the frog Leptodacylus vastus, presents a structural conformation distinct from any protein structures yet reported. So, in the current study we aimed to reveal the protein composition of the foam nest of L. vastus and further characterize the Lv-RSN-1. Proteomic analysis showed the foam nest contains more than 100 of proteins, and that Lv-RSN-1 comprises 45% of the total proteins, suggesting a key role in the nest construction and stability. We demonstrated by Western blotting that Lv-RSN-1 is mainly produced only by the female in the pars convoluta dilata, which highlights the importance of the female preservation for conservation of species that depend on the production of foam nests in the early stages of development. Overall, our results showed the foam nest of L. vastus is composed of a great diversity of proteins and that besides Lv-RSN-1, the main protein in the foam, other proteins must have a coadjuvant role in building and stability of the nest.

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

    DEFF Research Database (Denmark)

    Kougias, Panagiotis; Tsapekos, Panagiotis; Boe, Kanokwan

    . 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...... study was to investigate the effect of organic loading rate on foam formation and also to evaluate the antifoam efficiency of different chemical compounds on foam suppression. Thus, the impact of organic loading rate on anaerobic digestion foaming was studied in a continuous mode experiment...... stability The results obtained from the above experiments showed that the organic loading rate had a significant impact on foam formation. Finally, it was observed that using specific chemical defoamers, the foaming propensity of the substrate was minimized. However, the efficiency of the defoamers varied...

  8. 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.

  9. TIG AISI-316 welds using an inert gas welding chamber and different filler metals: Changes in mechanical properties and microstructure

    Directory of Open Access Journals (Sweden)

    Sánchez, A.

    2010-12-01

    Full Text Available This report analyses the influence of the use of an inert gas welding chamber with a totally inert atmosphere on the microstructure and mechanical properties of austenitic AISI 316L stainless steel TIG welds, using AISI ER316L, AISI 308L and Inconel 625 as filler metals. When compared with the typical TIG process, the use of the inert gas chamber induced changes in the microstructure, mainly an increase in the presence of vermicular ferrite and ferrite stringers, what resulted in higher yield strengths and lower values of hardness. Its effect on other characteristics of the joins, such as tensile strength, depended on the filler metal. The best combination of mechanical characteristics was obtained when welding in the inert gas chamber using Inconel 625 as filler metal.

    En este estudio se analiza la influencia que el uso de una cámara de soldadura de gas inerte tiene sobre la microestructura y las propiedades mecánicas de las soldaduras TIG en el acero inoxidable austenítico AISI-316L cuando se emplean AISI ER316L, AISI 308L e Inconel 625 como materiales de aporte. Cuando se compara con el típico proceso de TIG, el uso de una cámara de gas inerte induce cambios en la microestructura, incrementando la presencia de ferrita vermicular y de laminillas de ferrita, resultando en un aumento del límite elástico y una pérdida de dureza. Su influencia sobre otras características de las soldaduras como la carga de rotura depende de la composición del material de aporte. La mejor combinación de propiedades mecánicas se obtuvo usando el Inconel 625 como material de aporte y soldando en la cámara de gas inerte.

  10. Foam droplet separation for nanoparticle synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Tyree, Corey A.; Allen, Jonathan O. [Arizona State University, Department of Chemical Engineering (United States)], E-mail: joallen@asu.edu

    2008-03-15

    A novel approach to nanoparticle synthesis was developed whereby foam bubble bursting produced aerosol droplets, an approach patterned after the marine foam aerosol cycle. The droplets were dried to remove solvent, leaving nanometer-sized particles composed of precursor material. Nanoparticles composed of sodium chloride (mean diameter, D-bar{sub p} {approx} 100 nm), phosphotungstic acid (D-bar{sub p} {approx} 55 nm), and bovine insulin (D{sub p} {approx} 5-30 nm) were synthesized. Foam droplet separation can be carried out at ambient temperature and pressure. The 'soft' nature of the process makes it compatible with a wide range of materials.

  11. Foam Finishing%发泡涂饰

    Institute of Scientific and Technical Information of China (English)

    Dr. W. Wenzel; K. Pisaric; W. Schwaiger

    2006-01-01

    介绍了发泡剂在制革中的应用.详细给出了发泡剂的生产工艺以及需要不同成革的涂饰配方.结果表明,发泡涂饰对成革性能有明显改善.%The article introduced the application of foam in leather-making. The rules and production process of foam were supplied indetails. It also discussed the finish formulation and possible methods of application for different leather. The foam finishing can evidently improve the properties of leather.

  12. Behaviour of aluminum foam under fire conditions

    Directory of Open Access Journals (Sweden)

    J. Grabian

    2008-07-01

    Full Text Available Taking into account fire-protection requirements it is advantageous for aluminum foam, after melting at a temperature considerably exceeding the melting point, to have a structure of discontinuous suspension of solid inclusions to liquid metal instead of liquid consistency. Continuity of the suspension depends on the solid phase content. The boundary value of the phase determined by J. Śleziona, above which the suspension becomes discontinuous, is provided by the formula (1. Figure 1 presents the relationship graphically. Boundary values of the vs content resulting from the above relationship is too low, taking into account the data obtained from the technology of suspension composites [4]. Therefore, based on the structure assumed for the suspension shown in Figure 2 these authors proposed another way of determining the contents, the value of which is determined by the relationship (3 [5].For purposes of the experimental study presented in the paper two foams have been molten: a commercially available one, made by aluminum foaming with titanium hydride, and a foam manufactured in the Marine Materials Plant of the Maritime University of Szczecin by blowing the AlSi7 +20% SiC composite with argon. Macrophotographs of foam cross-sections are shown in Figure 3. The foams have been molten in the atmosphere of air at a temperature of 750ºC. The products of melting are presented in Figure 4. It appears that molten aluminum foam may have no liquid consistency, being unable to flow, which is a desired property from the point of view of fire-protection. The above feature of the molten foam results from the fact that it may be a discontinuous suspension of solid particles in a liquid metal. The suspended particles may be solid particles of the composite that served for making the foam or oxide membranes formed on extended metal surface of the bubbles included in the foam. The desired foam ability to form a discontinuous suspension after melting may be

  13. Marangoni effects in aqueous polypropylene glycol foams.

    Science.gov (United States)

    Tan, Su Nee; Fornasiero, Daniel; Sedev, Rossen; Ralston, John

    2005-06-15

    The foam behavior of three polypropylene glycols covering the molecular weight range between 192 and 725 g/mol has been examined. Static and dynamic surface tension data, as well as bubble size distribution and retention time in the foam, were incorporated into a simple model of foam stability. The latter clearly indicates that surface tension differences between the plateau border and lamellar region adjacent to the bubble surface are the dominant factor in controlling foamability, causing liquid flow in the direction opposite to liquid drainage, a process termed the Marangoni effect.

  14. Characterization Of Oxide Layers Produced On The AISI 321 Stainless Steel After Annealing

    Directory of Open Access Journals (Sweden)

    Bochnowski W.

    2015-09-01

    Full Text Available In this study, the structure, chemical composition and topography of oxide layers produced on the surface of the AISI 321 austenitic steel in the annealing process were analyzed. Heat treatment was done at 980°C temperature for 1 hour time in different conditions. The annealing was done in a ceramic furnace in oxidation atmosphere and in vacuum furnaces with cylindrical molybdenum and graphite chambers. The analysis was carried out using the following methods: a scanning electron microscope (SEM equipped with an energy-dispersive X-ray spectrometer (EDX, a transmission electron microscope (TEM equipped with an energy-dispersive X-ray spectrometer (EDX, an X-ray diffractometer (XRD, a secondary ion mass spectrometer with time-of-flight mass analyzer (TOF SIMS and an atomic force microscope (AFM. The oxide layer formed during annealing of the AISI 321 steel at 980°C consisted of sub-layers, diversified in the chemical composition. The thickness of the oxidized layer is depended on the annealing conditions. In a ceramic furnace in oxidation atmosphere, the thickness of the oxide layer was of 300-500 nm, in a vacuum furnace with molybdenum and graphite heating chambers, it ranged from 40 to 300 nm and from a few to 50 nm, respectively. TOF SIMS method allows to get average (for the surface of 100 μm × 100 μm depth profiles of concentration of particular elements and elements combined with oxygen. In oxide layers formed in vacuum furnaces there are no iron oxides. Titanium, apart from being bounded with carbon in carbides, is a component of the oxide layer formed on the surface of the AISI 321 steel.

  15. Kinetic study of rigid polyurethane foams thermal decomposition by artificial neural network

    CERN Document Server

    Ferreira, Bárbara D L; Yoshida, Maria Irene; Sebastião, Rita C O

    2016-01-01

    Kinetic models of solid thermal decomposition are traditionally used for individual fit of isothermal decomposition experimental data. However, this methodology can provide unacceptable errors in some cases. To solve this problem, a neural network (MLP) was developed and adopted in this work. The implemented algorithm uses the rate constants as predetermined weights between the input and intermediate layer and kinetic models as activation functions of neurons in the hidden layer. The contribution of each model in the overall fit of the experimental data is calculated as the weights between the intermediate and output layer. In this way, the phenomenon is better described as a sum of kinetic processes. Two rigid polyurethane foam samples: loaded with Al2O3 and no inorganic filler were used in this work. The R3 model described the thermal decomposition kinetic process for all temperatures for both foams with smaller residual error. However, the network residual errors are on average 102 times lower compared to ...

  16. Electrochemical and pitting corrosion resistance of AISI 4145 steel subjected to massive laser shock peening treatment with different coverage layers

    Science.gov (United States)

    Lu, J. Z.; Han, B.; Cui, C. Y.; Li, C. J.; Luo, K. Y.

    2017-02-01

    The effects of massive laser shock peening (LSP) treatment with different coverage layers on residual stress, pitting morphologies in a standard corrosive solution and electrochemical corrosion resistance of AISI 4145 steel were investigated by pitting corrosion test, potentiodynamic polarisation test, and SEM observations. Results showed massive LSP treatment can effectively cause an obvious improvement of pitting corrosion resistance of AISI 4145 steel, and increased coverage layer can also gradually improve its corrosion resistance. Massive LSP treatment with multiple layers was shown to influence pitting corrosion behaviour in a standard corrosive solution.

  17. Resistencia a la abrasión vs. resistencia al impacto del acero aisi 15b30, templado + revenido

    OpenAIRE

    HORACIO SIERRA RESTREPO; DIANA MARCELA TOBÓN

    2008-01-01

    Debido al bajo carbono de los aceros al boro, algunos fabricantes recomiendan el revenido como tratamiento opcional y otros sugieren que no es necesario. Puesto que los aceros al boro son muy utilizados en aplicaciones agrícolas donde tienen exigencias de desgaste e impacto, (p.ej. discos de arados), es, entonces, conveniente evaluar dichas propiedades del acero AISI 15B30 con temple y temple más revenido a diferentes temperaturas y contrastarlo con características del AISI 1030, obtenidas en...

  18. An Electrochemical Impedance Study of AISI 321 Stainless Steel in 0.5 M H2SO4

    Directory of Open Access Journals (Sweden)

    A. Fattah-Alhosseini

    2011-01-01

    Full Text Available The electrochemical behavior of passive films formed on AISI 321 has been examined using electrochemical impedance spectroscopy. AISI 321 is characterized by high interfacial impedance, thereby illustrating its high corrosion resistance. Results showed that the interfacial impedance and the polarization resistance initially increase with applied potential, within the low potential. However, at a sufficiently high potential (>0.6 V, the interfacial impedance and the polarization resistance decrease with increasing potential. The impedance data were adequately represented by an equivalent electrical circuit model based on point defect model, which described the behavior of the passive film on stainless steel more satisfactorily than the proposed models.

  19. PITTING CORROSION OF AISI 316Ti STAINLESS STEEL WITH POLISHED SURFACE

    Directory of Open Access Journals (Sweden)

    Viera Zatkalíková

    2010-05-01

    Full Text Available AISI 316Ti is Cr–Ni–Mo austenitic stainless steel with the high Pitting Resistance Equivalent Number (PREN. The effect of the surface finishing by polishing on the pitting corrosion resistance was tested in aggressive 5% FeCl3 solution. The immersion tests were curried out at the temperature 30, 50, 80 °C. The electrochemical cyclic potentiodynamic tests were carried out in the same solution at temperature 30 and 50 °C. The evaluation of the corrosion resistance arose from the comparison of the results of the immersion and the cyclic potentiodynamic tests.

  20. "CARACTERIZACIÓN Y PROPIEDADES MECANICAS DE LA SOLDADURA DE UN ACERO INOXIDABLE FERRIRICO AISI 430"

    OpenAIRE

    Moreno Rodríguez, Arturo

    2012-01-01

    En la presente trabajo se investiga la soldabilidad del acero inoxidable ferrítico AISI 430. Las propiedades mecánicas y la microestructura se relacionan con las variables operativas del proceso de soldadura, de ahí que jueguen un papel importante para lograr óptimas propiedades. Buscando la mejora de las propiedades mecánicas de las uniones soldadas, posteriormente, se les aplicó un tratamiento térmico post-soldadura. Las uniones se realizaron mediante el proceso de soldadu...

  1. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.

    2005-01-01

    laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  2. The structural characterization of some biomaterials, type AISI 310, used in medicine

    Science.gov (United States)

    Minciuna, M. G.; Vizureanu, P.; Hanganu, C.; Achitei, D. C.; Popescu, D. C.; Focsaneanu, S. C.

    2016-06-01

    Orthopedics biomaterials are intended for implantation in the human body and substituted or help to repair of bones, cartilage or organ transplant, and tendons. At the end of the 20th century, the availability of materials for the manufacture implants used in medicine has been the same as for other industrial applications. The most used metals for manufacturing the orthopedics implants are: stainless steels, cobalt-chrome-molybdenum alloys, titanium and his alloys. The structural researches which are made in this paper, offer a complete analysis of AISI310 stainless steels, using: optical spectrometry, X-ray diffraction and scanning electronic microscopy.

  3. Biaxial fatigue tests of notched specimens for AISI 304L stainless steel

    Directory of Open Access Journals (Sweden)

    G. Beretta

    2016-07-01

    Full Text Available High cycle fatigue tests were conducted for stainless steel AISI 304L. The geometry was a thin walled tube with a passing through hole. The tests were axial, torsional and in-phase axial-torsional, all of them under load control with R = −1. The S-N curves were constructed following the ASTM E739 standard and the fatigues limits were calculated following the method of maximum likelihood proposed by Bettinelli. The crack direction along the surface was analysed, with especial attention to the crack initiation zones. The notch fatigue limits for different hole diameters were compared with the predictions done with a microstructural fracture mechanics model.

  4. Active flux tungsten inert gas welding of austenitic stainless steel AISI 304

    OpenAIRE

    Klobčar, D.; J. Tušek; Bizjak, M.; S. Simončič; V. Lešer

    2016-01-01

    The paper presents the effects of flux assisted tungsten inert gas (A-TIG) welding of 4 (10) mm thick austenitic stainless steel EN X5CrNi1810 (AISI 304) in the butt joint. The sample dimensions were 300 ´ 50 mm, and commercially available active flux QuickTIG was used for testing. In the planned study the influence of welding position and weld groove shape was analysed based on the penetration depth. A comparison of microstructure formation, grain size and ferrit number between TIG welding a...

  5. Estructura cristalina del acero AISI 1045 deformado plásticamente

    Directory of Open Access Journals (Sweden)

    Tomás Fernández Columbié

    2008-01-01

    Full Text Available Se abordó el comportamiento microestructural del acero AISI 1045 endurecido mediante la Deformación Plástica Superficial por rodillo, Se establece el mecanismo de endurecimiento del acero por el deslizamiento de los granos en la red cristalina y se demuestra el fenómeno de la acritud, la cual es producto del tensionamiento de los granos cuando el material es sometido al tensionamiento de su estructura cristalina. Se establece el procedimiento experimental realizado después que las probetas fueron sometidas al proceso de deformación.

  6. Estructura cristalina del acero AISI 1045 deformado plásticamente

    OpenAIRE

    Tomás Fernández Columbié; Isnel Rodríguez González; Dayanis Alcántara Borges

    2008-01-01

    Se abordó el comportamiento microestructural del acero AISI 1045 endurecido mediante la Deformación Plástica Superficial por rodillo, Se establece el mecanismo de endurecimiento del acero por el deslizamiento de los granos en la red cristalina y se demuestra el fenómeno de la acritud, la cual es producto del tensionamiento de los granos cuando el material es sometido al tensionamiento de su estructura cristalina. Se establece el procedimiento experimental realizado después que las probetas fu...

  7. Variación microestructural del acero AISI 1045 endurecido por rodadura

    OpenAIRE

    Esther Fernández-Guilarte; Dayanis Alcántara-Borges; Isnel Rodríguez-González; Tomás Fernández-Columbié

    2010-01-01

    En este trabajo se analiza el comportamiento microestructural del acero AISI 1045, endurecido mediante deformación plástica superficial por rodillo, empleando como variables en el proceso de endurecimiento el número de revoluciones, avance y fuerza del torno 16D20. Se empleó el análisis espectral para determinar la composición química del acero y el Nital como reactivo químico para resaltar la estructura metalográfica después de pulida. Se establecen los parámetros de los regímenes de la defo...

  8. Microstructural changes due to laser surface melting of an AISI 304 stainless steel

    Directory of Open Access Journals (Sweden)

    d?Oliveira A.S.C.M.

    2001-01-01

    Full Text Available Several techniques can be used to improve surface properties. These can involve changes on the surface chemical composition (such as alloying and surface welding processes or on the surface microstructure, such as hardening and melting. In the present work surface melting with a 3kW CO2 cw laser was done to alter surface features of an AISI 304 stainless steel. Microstructure characterisation was done by optical and scanning electron microscopy. Vickers and Knoop microhardness tests evaluated mechanical features after surface melting. Phase transformation during rapid solidification is analysed and discussed.

  9. Estimation of embrittlement during aging of AISI 316 stainless steel TIG welds

    Indian Academy of Sciences (India)

    J Nayak; K R Udupa; K R Hebbar; H V S Nayak

    2004-12-01

    Weldments of AISI grade 316 stainless steel, having a ferrite content of 4–6% and a variety of nitrogen concentrations were prepared using a modified element implant technique. Charpy impact specimens prepared from these weldments were subjected to a variety of aging treatments. Impact toughness decreases with aging time at all aging temperatures. Nitrogen is found to be beneficial to toughness. An empirical relation connecting the aging temperature, aging time and nitrogen content with toughness has been developed which can be used to estimate the time for embrittlement.

  10. 1020 AISI-SAE steel Austenitic Nitrocarburising with alcohol and triethanolamine

    Directory of Open Access Journals (Sweden)

    Álvaro Castro P

    2010-04-01

    Full Text Available The present work shows AISI-SAE 1020 steel's nitrocarbide layer's microstructure and micro-hardness profile following 4 hours at 700ºC using methanol, isopropanol and triethanolamine. The steel was then hardened by quenching it in water and then tempered at 350ºC for 1 hour. Its surface had been partially oxidised by heating it at 400ºC for 1 hour. An example is given of other researchers analysing microstructure and propierties in steel having 0,5% C, using endothermic gas and different amounts of ammoniac.

  11. HTS SQUID application for measuring the magnetic properties of AISI type 316L(N) steel

    Energy Technology Data Exchange (ETDEWEB)

    Park, D.G. E-mail: dgpark@nanum.kaeri.re.kr; Kim, D.W.; Hong, J.H.; Timofeev, V.P.; Kim, C.G

    2000-06-02

    A portable RF HTS SQUID-based susceptometer was used for small-size magnetized sample testing in weak DC (up to 200 A/m) and AC (up to 4 A/m) magnetic fields. The system resolution for the magnetic moment is of the order of 1.6x10{sup -10} A m{sup 2}. The measured DC susceptibility of a tested sample of Gd{sub 88}La{sub 12} agrees well with the value obtained by using a commercial liquid helium susceptometer. The measured volume susceptibility of AISI type 316L(N) steel increases after fatigue due to the microcrack induced by cyclic stress.

  12. Investigating early stages of biocorrosion with XPS: AISI 304 stainless steel exposed to Burkholderia species

    Science.gov (United States)

    Johansson, Leena-Sisko; Saastamoinen, Tuomas

    1999-04-01

    We have investigated the interactions of an exopolymer-producing bacteria, Burkholderia sp. with polished AISI 304 stainless steel substrates using X-ray photoelectron spectroscopy (XPS). Steel coupons were exposed to the pure bacteria culture in a specially designed flowcell for 6 h during which the experiment was monitored in situ with an optical microscope. XPS results verified the formation of biofilm containing extracellular polymer on all the samples exposed to bacteria. Sputter results indicated that some ions needed for metabolic processes were trapped within the biofilm. Changes in the relative Fe concentration and Fe 2p peak shape indicated that also iron had accumulated into the biofilm.

  13. Mechanical Properties of Stellite-6 coated AISI 316L Stainless Steel

    Directory of Open Access Journals (Sweden)

    Pushpinderjit Singh

    2016-01-01

    Full Text Available Present paper describes the mechanical properties of Stellite-6 coated AISI 316 L stainless steel. Specimens were coated using Detonation Gun thermal spray process, with different coating thicknesses of Stellite-6 ranging from 50 µm to 150 µm. Afterwards their properties like tensile strength, impact strength and micro hardness were evaluated on the basis of the results obtained from the experimentation. For comparison of substrate and coated material the graphs were plotted. The coated specimens exhibited superior impact strength and microhardness than that of the bare specimens, whereas the tensile strength of coated specimens decreased marginally with the increase in coating thickness.

  14. Gel cast foam diesel particulate filters

    Energy Technology Data Exchange (ETDEWEB)

    Binner, J.G.P.; Hughes, S. [IPTME, Loughborough Univ., Loughborough (United Kingdom); Sambrook, R.M. [Dytech Corp. Ltd., Dronfield (United Kingdom)

    2004-07-01

    A new manufacturing route for foam ceramics based on gel casting has been developed and is being commercialised. Gel casting employs an organic monomer that is polymerised to cause the in-situ gelation of a foamed aqueous ceramic slurry. The primary advantage is the inherent flexibility of the process; the foams can be near net shape manufactured in a variety of shapes and sizes and after production are simply dried and fired. In addition, the porosity and pore size distribution can be varied to suit the application and a wide range of ceramics can be foamed with densities ranging from 5-40% of theoretical. Applications are diverse and include the potential to be used as diesel particulate filters (DPF). The present work examines this and concludes that filtration efficiencies of {>=}90% are achievable without generating a significant backpressure for the engine. (orig.)

  15. Feynman propagator for spin foam quantum gravity.

    Science.gov (United States)

    Oriti, Daniele

    2005-03-25

    We link the notion causality with the orientation of the spin foam 2-complex. We show that all current spin foam models are orientation independent. Using the technology of evolution kernels for quantum fields on Lie groups, we construct a generalized version of spin foam models, introducing an extra proper time variable. We prove that different ranges of integration for this variable lead to different classes of spin foam models: the usual ones, interpreted as the quantum gravity analogue of the Hadamard function of quantum field theory (QFT) or as inner products between quantum gravity states; and a new class of causal models, the quantum gravity analogue of the Feynman propagator in QFT, nontrivial function of the orientation data, and implying a notion of "timeless ordering".

  16. Multifunctional nanocomposite foams for space applications

    Science.gov (United States)

    Rollins, Diandra J.

    Materials combined with a small amount of nanoparticles offer new possibilities in the synthesizing of multifunctional materials. Graphene nanoplatelets (GnP) are multifunctional nanoreinforcing agents consisting of stacks of graphene sheets with comparable properties to a single graphene layer at an overall lower cost in a more robust form. Such particles have been shown to have good thermal, mechanical and electrical properties. In addition, a low density multifunctional nanocomposite foam has the potential for multiple applications and potential use for the aerospace industry. This dissertation investigates two different microporous (foam) polymers that are modified by the addition of GnP to combat this density effect to improve the foam's macroscopic properties Three sizes of GnP with varying aspect ratio were used to improve the polymeric foams' dielectric, electrical and mechanical properties. (Abstract shortened by ProQuest.).

  17. Dynamic indentation on layered polypropylene foams

    Directory of Open Access Journals (Sweden)

    Viot P.

    2012-08-01

    Full Text Available Foams, and particularly the polypropylene foam, are more and more often used in the area of injury protection and passive safety for its energy absorption capacity. This multi-scale material is constituted of mesoscopic beads with a large variability of the material properties. First, to study the effects of these mesoscopic heterogeneities on both the macroscopic and the local behaviors, numerical simulations on virtual volumes of foam under dynamic loading have been performed. The influence of the organized system of heterogeneities has also been studied in the cases of a random distribution and a multi-layered volume. Experimental dynamic compressive tests have been performed on multi-layered volumes of foam and compared with the results of the Finite Element Method. Second, indentation experiments have also been performed using a cylindrical shape indenter.

  18. Spin foam models as energetic causal sets

    CERN Document Server

    Cortês, Marina

    2014-01-01

    Energetic causal sets are causal sets endowed by a flow of energy-momentum between causally related events. These incorporate a novel mechanism for the emergence of space-time from causal relations. Here we construct a spin foam model which is also an energetic causal set model. This model is closely related to the model introduced by Wieland, and this construction makes use of results used there. What makes a spin foam model also an energetic causal set is Wieland's identification of new momenta, conserved at events (or four-simplices), whose norms are not mass, but the volume of tetrahedra. This realizes the torsion constraints, which are missing in previous spin foam models, and are needed to relate the connection dynamics to those of the metric, as in general relativity. This identification makes it possible to apply the new mechanism for the emergence of space-time to a spin foam model.

  19. Spherical foam growth in Al alloy melt

    Institute of Scientific and Technical Information of China (English)

    SHANG; Jintang; HE; Deping

    2005-01-01

    Due to the demand of high-tech Al alloy foam with spherical pores, high strength and high energy-absorption capacity has become one of the research foci. The aim of this study is to ascertain the growth regularity of spherical foam in Al alloy melt. Three-dimensional packing model such as face-centered cubic is established to study the spherical foam growth. Theoretical results are compared with experimental ones, and the face-centered cubic model corresponds well with the experiment. It is reasonable to assume that the pores have the same radius, the total pore number keeps unchanged and spherical foam grows with face-centered cubic packing mode. This study presents a useful help to control the average pore radius and film thickness.

  20. Open Cell Metal Foams for Beam Liners?

    CERN Document Server

    Croce, R P; Stabile, A

    2013-01-01

    The possible use of open-cell metal foams for particle accelerator beam liners is considered. Available materials and modeling tools are reviewed, potential pros and cons are pointed out, and a study program is outlined.

  1. A Method to Produce Foam Glasses

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a production process of foam glass from a mixture of glass cullet or slag or fly ash with a foaming agent and an oxidizing agent and heating to below 1100 C under low oxygen atmosphere. The invention relates more particularly to a process wherein pure carbon...... or a compound which yields pure carbon as the foaming agent is oxidized by a sufficient amount of an efficient oxidizing agent essentially added to the glass-carbon powder mixture, where the oxidizing agent supplies oxygen in the relevant temperature range, to release CO/CO2 gas mixture in the softened glass...... at elevated temperature, to form a foamed material with CO2 gas filled cells....

  2. Foam inflated rigidized structures for space applications

    Science.gov (United States)

    Lester, D. M.; Warner, M. J.; Blair, M.

    1993-11-01

    Large lightweight stowable structures that can be deployed in space without astronaut extra vehicular activity are vital to expanding space exploration and utilization. To meet this challenge Foam Inflated Rigidized (FIR) structures have been developed by Thiokol Corporation on the Air Forces's Gossamer Baggie Torus program. In this paper the development, proof of concept demonstration of an eight foot diameter octagonal torus, and design application of this technology for structural elements to stabilize the solar collector of a solar thermal rocket are discussed. A FIR structure uses foam to inflate and pre-stress a resin impregnated fabric skin. The predeployed foam used was a solvent swelled polymer that foams immediately when exposed to vacuum due to rapid solvent loss. This property allows a very simple deployment mechanism to be used in erecting these structures. Once inflated, the skin resin is cured using the available ultraviolet radiation. By using high strength and stiffness fiber materials a stiff, strong lightweight structure was produced.

  3. Flame Retardants Used in Flexible Polyurethane Foam

    Science.gov (United States)

    The partnership project on flame retardants in furniture seeks to update the health and environmental profiles of flame-retardant chemicals that meet fire safety standards for upholstered consumer products with polyurethane foam

  4. Dynamic indentation on layered polypropylene foams

    Science.gov (United States)

    Maheo, L.; Viot, P.

    2012-08-01

    Foams, and particularly the polypropylene foam, are more and more often used in the area of injury protection and passive safety for its energy absorption capacity. This multi-scale material is constituted of mesoscopic beads with a large variability of the material properties. First, to study the effects of these mesoscopic heterogeneities on both the macroscopic and the local behaviors, numerical simulations on virtual volumes of foam under dynamic loading have been performed. The influence of the organized system of heterogeneities has also been studied in the cases of a random distribution and a multi-layered volume. Experimental dynamic compressive tests have been performed on multi-layered volumes of foam and compared with the results of the Finite Element Method. Second, indentation experiments have also been performed using a cylindrical shape indenter.

  5. Piezoresistive Foam Sensor Arrays for Marine Applications

    CERN Document Server

    Dusek, Jeff E; Lang, Jeffrey H

    2016-01-01

    Spatially-dense pressure measurements are needed on curved surfaces in marine environments to provide marine vehicles with the detailed, real-time measurements of the near-field flow necessary to improve performance through flow control. To address this challenge, a waterproof and conformal pressure sensor array comprising carbon black-doped-silicone closed-cell foam (CBPDMS foam) was developed for use in marine applications. The response of the CBPDMS foam sensor arrays was characterized using periodic hydrodynamic pressure stimuli from vertical plunging, from which a piecewise polynomial calibration was developed to describe the sensor response. Inspired by the distributed pressure and velocity sensing capabilities of the fish lateral line, the CBPDMS foam sensor arrays have significant advantages over existing commercial sensors for distributed flow reconstruction and control. Experimental results have shown the sensor arrays to have sensitivity on the order of 5 Pascal, dynamic range of 50-500 Pascal; are...

  6. Macroporous polymer foams by hydrocarbon templating

    OpenAIRE

    Shastri, Venkatram Prasad; Martin, Ivan; Langer, Robert

    2000-01-01

    Porous polymeric media (polymer foams) are utilized in a wide range of applications, such as thermal and mechanical insulators, solid supports for catalysis, and medical devices. A process for the production of polymer foams has been developed. This process, which is applicable to a wide range of polymers, uses a hydrocarbon particulate phase as a template for the precipitation of the polymer phase and subsequent pore formation. The use of a hydrocarbon template allows for enhanced control ov...

  7. Silica Foams for Fire Prevention and Firefighting.

    Science.gov (United States)

    Vinogradov, Alexander V; Kuprin, D S; Abduragimov, I M; Kuprin, G N; Serebriyakov, Evgeniy; Vinogradov, Vladimir V

    2016-01-13

    We report the new development of fire-extinguishing agents employing the latest technology of fighting and preventing fires. The in situ technology of fighting fires and explosions involves using large-scale ultrafast-gelated foams, which possess new properties and unique characteristics, in particular, exceptional thermal stability, mechanical durability, and full biocompatibility. We provide a detailed description of the physicochemical processes of silica foam formation at the molecular level and functional comparison with current fire-extinguishing and fire-fighting agents. The new method allows to produce controllable gelation silica hybrid foams in the range from 2 to 30 s up to 100 Pa·s viscosity. Chemical structure and hierarchical morphology obtained by scanning electron microscopy and transmission electron microscopy images develop thermal insulation capabilities of the foams, reaching a specific heat value of more than 2.5 kJ/(kg·°C). The produced foam consists of organized silica nanoparticles as determined by X-ray photoelectron spectroscopy and X-ray diffraction analysis with a narrow particle size distribution of ∼10-20 nm. As a result of fire-extinguishing tests, it is shown that the extinguishing efficiency exhibited by silica-based sol-gel foams is almost 50 times higher than that for ordinary water and 15 times better than that for state-of-the-art firefighting agent aqueous film forming foam. The biodegradation index determined by the time of the induction period was only 3 d, while even for conventional foaming agents this index is several times higher.

  8. Basic Physics Of Foam Stability And Collapse

    Science.gov (United States)

    2012-06-18

    Milton, “ Surfactants and Interfacial Phenomena ”, John Wiley & Sons, New York, 1978, pg. 149-151, 174-178, 200-210. [9] Bergeron, V., Cooper, P...Young for a single soap bubble 6 4.2 ........................................................................... Surfactant transport due to film...research is to understand how to reduce foam formation in oils; there is more fundamental understanding of how surfactants stabilize foams. The stability

  9. Fire resistant resilient foams. [for seat cushions

    Science.gov (United States)

    Gagliani, J.

    1976-01-01

    Primary program objectives were the formulation, screening, optimization and characterization of open-cell, fire resistant, low-smoke emitting, thermally stable, resilient polyimide foams suitable for seat cushions in commercial aircraft and spacecraft. Secondary program objectives were to obtain maximum improvement of the tension, elongation and tear characteristics of the foams, while maintaining the resiliency, thermal stability, low smoke emission and other desirable attributes of these materials.

  10. Espresso coffee foam delays cooling of the liquid phase.

    Science.gov (United States)

    Arii, Yasuhiro; Nishizawa, Kaho

    2017-04-01

    Espresso coffee foam, called crema, is known to be a marker of the quality of espresso coffee extraction. However, the role of foam in coffee temperature has not been quantitatively clarified. In this study, we used an automatic machine for espresso coffee extraction. We evaluated whether the foam prepared using the machine was suitable for foam analysis. After extraction, the percentage and consistency of the foam were measured using various techniques, and changes in the foam volume were tracked over time. Our extraction method, therefore, allowed consistent preparation of high-quality foam. We also quantitatively determined that the foam phase slowed cooling of the liquid phase after extraction. High-quality foam plays an important role in delaying the cooling of espresso coffee.

  11. Additive Manufacturing of Tooling for Refrigeration Cabinet Foaming Processes

    Energy Technology Data Exchange (ETDEWEB)

    Post, Brian K [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nuttall, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cukier, Michael [Whirlpool Corp., Benton Harbor, MI (United States); Hile, Michael [Whirlpool Corp., Benton Harbor, MI (United States)

    2016-07-29

    The primary objective of this project was to leverage the Big Area Additive Manufacturing (BAAM) process and materials into a long term, quick change tooling concept to drastically reduce product lead and development timelines and costs. Current refrigeration foam molds are complicated to manufacture involving casting several aluminum parts in an approximate shape, machining components of the molds and post fitting and shimming of the parts in an articulated fixture. The total process timeline can take over 6 months. The foaming process is slower than required for production, therefore multiple fixtures, 10 to 27, are required per refrigerator model. Molds are particular to a specific product configuration making mixed model assembly challenging for sequencing, mold changes or auto changeover features. The initial goal was to create a tool leveraging the ORNL materials and additive process to build a tool in 4 to 6 weeks or less. A secondary goal was to create common fixture cores and provide lightweight fixture sections that could be revised in a very short time to increase equipment flexibility reduce lead times, lower the barriers to first production trials, and reduce tooling costs.

  12. Drying Spirulina with Foam Mat Drying at Medium Temperature

    Directory of Open Access Journals (Sweden)

    Aji Prasetyaningrum

    2012-10-01

    Full Text Available Spirulina is a single cell blue green microalgae (Cyanobacteria containing many Phytonutrients (Beta-carotene, Chlorophyl, Xanthophyl, Phyocianin using as anti-carcinogen in food. Producing dry spirulina by quick drying process at medium temperature is very important to retain the Phytonutrient quality. Currently, the work is still challenging due to the gel formation that block the water diffusion from inside to the surface.  This research studies the performance of foam-mat drying on production of dry spirulina. In this method the spirulina was mixed with foaming agent (glair/egg albumen, popular as white egg at 2.5% by weight at air velocity 2.2 m/sec. Here, the effect of spirulina thickness and operational temperature on drying time and quality (Beta-carotene and color were observed. The drying time was estimated based on the measurement of water content in spirulina versus time. Result showed that the thicker spirulina, the longer drying time. Conversely, the higher operational temperature, faster drying time. At thickness ranging 1-3 mm and operational temperature below 70oC, the quality of spirulina can fit the market requirement

  13. Additive Manufacturing of Tooling for Refrigeration Cabinet Foaming Processes

    Energy Technology Data Exchange (ETDEWEB)

    Post, Brian K [ORNL

    2016-09-01

    The primary objective of this project was to leverage the Big Area Additive Manufacturing (BAAM) process and materials into a long term, quick change tooling concept to drastically reduce product lead and development timelines and costs. Current refrigeration foam molds are complicated to manufacture involving casting several aluminum parts in an approximate shape, machining components of the molds and post fitting and shimming of the parts in an articulated fixture. The total process timeline can take over 6 months. The foaming process is slower than required for production, therefore multiple fixtures, 10 to 27, are required per refrigerator model. Molds are particular to a specific product configuration making mixed model assembly challenging for sequencing, mold changes or auto changeover features. The initial goal was to create a tool leveraging the ORNL materials and additive process to build a tool in 4 to 6 weeks or less. A secondary goal was to create common fixture cores and provide lightweight fixture sections that could be revised in a very short time to increase equipment flexibility reduce lead times, lower the barriers to first production trials, and reduce tooling costs.

  14. Applications of Polymer Matrix Syntactic Foams

    Science.gov (United States)

    Gupta, Nikhil; Zeltmann, Steven E.; Shunmugasamy, Vasanth Chakravarthy; Pinisetty, Dinesh

    2013-11-01

    A collection of applications of polymer matrix syntactic foams is presented in this article. Syntactic foams are lightweight porous composites that found their early applications in marine structures due to their naturally buoyant behavior and low moisture absorption. Their light weight has been beneficial in weight sensitive aerospace structures. Syntactic foams have pushed the performance boundaries for composites and have enabled the development of vehicles for traveling to the deepest parts of the ocean and to other planets. The high volume fraction of porosity in syntactic foams also enabled their applications in thermal insulation of pipelines in oil and gas industry. The possibility of tailoring the mechanical and thermal properties of syntactic foams through a combination of material selection, hollow particle volume fraction, and hollow particle wall thickness has helped in rapidly growing these applications. The low coefficient of thermal expansion and dimensional stability at high temperatures are now leading their use in electronic packaging, composite tooling, and thermoforming plug assists. Methods have been developed to tailor the mechanical and thermal properties of syntactic foams independent of each other over a wide range, which is a significant advantage over other traditional particulate and fibrous composites.

  15. A crumb rubber modified syntactic foam

    Energy Technology Data Exchange (ETDEWEB)

    Li Guoqiang [Department of Mechanical Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States); Department of Mechanical Engineering, Southern University, Baton Rouge, LA 70813 (United States)], E-mail: guoli@me.lsu.edu; John, Manu [Department of Mechanical Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States)

    2008-02-15

    In this study, the impact response and residual strength of a crumb rubber modified syntactic foam, which contained up to 20% by volume of crumb rubbers, were investigated. The foam had a hybrid microstructure bridging over several length scales. It was formed by dispersing hollow glass beads and crumb rubber particles into a microfiber and nanoclay filled epoxy matrix. Sandwich beam specimens were prepared using the hybrid foam as core and fiber reinforced epoxy as facings. A low velocity impact test using an instrumented drop tower impact machine was conducted on the sandwich beams and control beams made of the foam only. Four-point bending tests were conducted on the impact damaged specimens and control specimens without impact damage. The effect of the hybrid foam on the low velocity impact response and residual strength was evaluated based on the test results. The stress field interaction was evaluated using a finite element analysis. It was found that the rubberized syntactic foam possessed a higher capacity to dissipate impact energy and to retain bending strength. There was a positive composite action between the hollow glass bead particles and crumb rubber particles by means of stress field interaction and reduction in stress concentration.

  16. Polyurethane Foam Impact Experiments and Simulations

    Science.gov (United States)

    Kipp, M. E.; Chhabildas, L. C.; Reinhart, W. D.; Wong, M. K.

    1999-06-01

    Uniaxial strain impact experiments with a rigid polyurethane foam of nominal density 0.22g/cc are reported. A 6 mm thick foam impactor is mounted on the face of a projectile and impacts a thin (1 mm) target plate of aluminum or copper, on which the rear free surface velocity history is acquired with a VISAR. Impact velocities ranged from 300 to 1500 m/s. The velocity record monitors the initial shock from the foam transmitted through the target, followed by a reverberation within the target plate as the wave interacts with the compressed foam at the impact interface and the free recording surface. These one-dimensional uniaxial strain impact experiments were modeled using a traditional p-alpha porous material model for the distended polyurethane, which generally captured the motion imparted to the target by the foam. Some of the high frequency aspects of the data, reflecting the heterogeneous nature of the foam, can be recovered with computations of fully 3-dimensional explicit representations of this porous material.

  17. Dynamic compressive behavior of foamed polyethylene film

    Directory of Open Access Journals (Sweden)

    Tateyama Kohei

    2015-01-01

    Full Text Available The foamed film as the shock absorption material has attracted much attention because it is thin (100 μm ∼ 400 μm and has a closed cell structure. However, the dynamic mechanical properties have not been reported in the foamed film. The purpose of this study is to elucidate the compressive behavior of the foamed polyethylene film at the wide strain rate range. First, the new compressive test apparatus for the dynamic strain rate, the drop-weight testing machine with opposed load cell, was developed, which can be also evaluated the dynamic stress equilibrium of the specimen. It is confirmed that the compressive flow stress increased with increasing the strain rate, regardless of the film thickness. The foamed polyethylene film has the high strain rate sensitivity in the quasi-static deformation. On the other hand, there is almost no change of the strain rate sensitivity in the dynamic and the impact deformation. In order to investigate the mechanism of strain rate dependence, the foamed polyethylene film was observed by X-ray computed tomography scanner before and after compressive test. The fracture of the closed cell only occurred in the quasi-static deformation. It was clarified that the strain rate sensitivity of the foamed film depends strongly on that of the construction material, polyethylene.

  18. Development of Alcoa aluminum foam products

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, J.D.; Crowley, M.D.; Wang, W.; Wilhelmy, D.M.; Hunter, D.E. [Alcoa Technical Center, Alcoa Center, PA (United States)

    2007-07-01

    A new lightweight aluminum foam product was described. The foam was made through the controlled decomposition of carbonate powders within molten aluminum and was able to resist both coalescence and drainage. The fine-celled aluminum foam derived its physical and mechanical properties from the properties of the aluminum alloy matrix from which they were produced. The rheology of the molten aluminum was modified to provide a superior mesostructure. Stabilization was achieved by creating a solid-gas-liquid suspension initiated by the addition of carbonates into an aluminum alloy melt. A cascade of chemical reactions then occurred within the melt to create a foamable suspension. Carbon monoxide (CO) was generated to initiate an additional sequence of chemical reactions which resulted in the formation of solid particles within the liquid metal. CO reacted with liquid Al to form graphite. The graphite then reacted with Al to form aluminum carbide (Al{sub 4}C{sub 3}). The microstructural, mesostructural, and mechanical character of the foams produced under different processing conditions were examined. Details of experimental test procedures were also described. It was concluded that the specific crush energy absorption was as high as 20 kJ/kg. The foam exhibited a bending stiffness that was approximately 20 to 30 times higher than balsa and polymer foams. 14 refs., 2 tabs., 7 figs.

  19. Injectable silk foams for soft tissue regeneration.

    Science.gov (United States)

    Bellas, Evangelia; Lo, Tim J; Fournier, Eric P; Brown, Joseph E; Abbott, Rosalyn D; Gil, Eun S; Marra, Kacey G; Rubin, J Peter; Leisk, Gary G; Kaplan, David L

    2015-02-18

    Soft tissue fillers are needed for restoration of a defect or augmentation of existing tissues. Autografts and lipotransfer have been under study for soft tissue reconstruction but yield inconsistent results, often with considerable resorption of the grafted tissue. A minimally invasive procedure would reduce scarring and recovery time as well as allow the implant and/or grafted tissue to be placed closer to existing vasculature. Here, the feasibility of an injectable silk foam for soft tissue regeneration is demonstrated. Adipose-derived stem cells survive and migrate through the foam over a 10-d period in vitro. The silk foams are also successfully injected into the subcutaneous space in a rat and over a 3-month period integrating with the surrounding native tissue. The injected foams are palpable and soft to the touch through the skin and returning to their original dimensions after pressure is applied and then released. The foams readily absorb lipoaspirate making the foams useful as a scaffold or template for existing soft tissue filler technologies, useful either as a biomaterial alone or in combination with the lipoaspirate.

  20. Foam film permeability: theory and experiment.

    Science.gov (United States)

    Farajzadeh, R; Krastev, R; Zitha, Pacelli L J

    2008-02-28

    The mass transfer of gas through foam films is a prototype of various industrial and biological processes. The aim of this paper is to give a perspective and critical overview of studies carried out to date on the mass transfer of gas through foam films. Contemporary experimental data are summarized, and a comprehensive overview of the theoretical models used to explain the observed effects is given. A detailed description of the processes that occur when a gas molecule passes through each layer that forms a foam film is shown. The permeability of the film-building surfactant monolayers plays an important role for the whole permeability process. It can be successfully described by the models used to explain the permeability of surfactant monolayers on aqueous sub-phase. For this reason, the present paper briefly discusses the surfactant-induced resistance to mass transfer of gases through gas-liquid interface. One part of the paper discusses the experimental and theoretical aspects of the foam film permeability in a train of foam films in a matrix or a cylinder. This special case is important to explain the gas transfer in porous media or in foams. Finally, this paper will highlight the gaps and challenges and sketch possible directions for future research.

  1. 76 FR 19182 - Petition for Rulemaking-Classification of Polyurethane Foam and Certain Finished Products...

    Science.gov (United States)

    2011-04-06

    ... Polyurethane Foam and Certain Finished Products Containing Polyurethane Foam as Hazardous Materials AGENCY... of State Fire Marshals (NASFM). The NASFM petitioned PHMSA to classify polyurethane foam and certain finished products containing polyurethane foam as hazardous material for purposes of transportation...

  2. Structural and Microhardness Changes After Turning of the AISI 1045 Steel for Minimum Quantity Cooling Lubrication

    Science.gov (United States)

    Maruda, Radoslaw W.; Krolczyk, Grzegorz M.; Michalski, Mariusz; Nieslony, Piotr; Wojciechowski, Szymon

    2017-01-01

    This work presents the cooling effect under minimum quantity cooling lubrication and dry cutting on structural changes and microhardness of the ferritic-pearlitic AISI 1045 steel after turning. Due to the fact that the AISI 1045 steel has a two-phase structure, microhardness tests using the Vickers method were conducted with a load of 0.05 HV separately for ferrite and pearlite grains. The tests showed that cooling of the cutting zone under minimum quantity cooling lubrication (MQCL) condition decreased the depth of the hardened layer compared to dry cutting by approximately 40% for both pearlite and ferrite. Scanning electron microscopy analysis revealed that applying MQCL limits the formation of plastic deformations, among others, by reducing the surface crumple zone by approximately 50% compared to dry cutting. As a result of cooling being applied to the cutting zone using the MQCL method, the average diameter of ferrite grains has been decreased in the entire surface area compared to dry cutting. When using dry cutting, clear structural changes of the surface layer were also observed. This may be the result of sulfide inclusions which have formed, causing microcracks on the edge of the hardened layer and surface deformation visible as notches.

  3. Physical and Tribological Properties of Nitrided AISI 316 Stainless Steel Balls

    Directory of Open Access Journals (Sweden)

    Yang Shicai

    2016-01-01

    Full Text Available AISI 316 austenitic stainless steel balls (diameters 5.0 and 12.0 mm, typical hardness 250 HV0.3 and flat samples (20×20×2.0 mm were nitrided by a pulsed glow discharge Ar/N2 plasma. Hardness of the ball surfaces was analysed using Vickers indentation. Thermal stability of the nitrided balls (diameter 12.0 mm was studied using a furnace to heat them in air for 8 hours at temperatures up to 700.0°C and then, after cooling to room temperature, the surface hardness of the heated balls was re-measured. Scanning electron microscopy and X-ray diffraction were used to study the microstructures, composition and phase formation of the nitrided sublayers. Unlubricated pin-on-disc wear testing was used to evaluate the wear resistance of nitrided stainless steel balls (5.0 mm diameter and the results were compared with similar testing on hardened Cr-Steel balls (5 mm diameter with hardness of about 650 HV0.3. All the test results indicated that the nitrided AISI 316 austenitic stainless steel balls have advantages over the hardened Cr-Steel balls in terms of retaining high hardness after heat treatment and high resistance to sliding wear at room temperature under higher counterpart stress. These properties are expected to be beneficial for wide range of bearing applications.

  4. Friction welding of AA6061 to AISI 4340 using silver interlayer

    Directory of Open Access Journals (Sweden)

    Suresh D. Meshram

    2015-09-01

    Full Text Available The present work pertains to the study on joining of AA6061 and AISI 4340 through continuous drive friction welding. The welds were evaluated by metallographic examination, X-ray diffraction, electron probe microanalysis, tensile test and microhardness. The study reveals that the presence of an intermetallic compound layer at the bonded interface exhibits poor tensile strength and elongation. Mg in AA6061 near to the interface is found to be favourable for the formation and growth of Fe2Al5 intermetallics. Introduction of silver as an interlayer through electroplating on AISI 4340 resulted in accumulation of Si at weld interface, replacing Mg at AA6061 side, thereby reducing the width of intermetallic compound layer and correspondingly increasing the tensile strength. Presence of silver at the interface results in partial replacement of Fe–Al based intermetallic compounds with Ag–Al based compounds. The presence of these intermetallics was confirmed by X-ray diffraction technique. Since Ag–Al phases are ductile in nature, tensile strength is not deteriorated and the silicon segregation at weld interface on AA6061 in the joints with silver interlayer acts as diffusion barrier for Fe and further avoids formation of Fe–Al based intermetallics. A maximum tensile strength of 240 MPa along with 4.9% elongation was obtained for the silver interlayer dissimilar metal welds. The observed trends in tensile properties and hardness were explained in relation to the microstructure.

  5. Microstructure and Properties of Plasma Source Nitrided AISI 316 Austenitic Stainless Steel

    Science.gov (United States)

    Li, G. Y.; Lei, M. K.

    2016-11-01

    Plasma source nitriding is a relatively new nitriding technology which can overcome those inherent shortcomings associated with conventional direct current plasma nitriding technology such as the arcing surface damage, the edging effect and the hollow cathode effect. There is considerable study on the properties of nitrided samples for laboratorial scale plasma source nitriding system; however, little information has been reported on the industrial-scale plasma source nitriding system. In this work, AISI 316 austenitic stainless steel samples were nitrided by an industrial-scale plasma source nitriding system at various nitriding temperatures (350, 400, 450 and 500 °C) with a floating potential. A high-nitrogen face-centered-cubic phase (γN) formed on the surface of nitrided sample surface. As the nitriding temperature was increased, the γN phase layer thickness increased, varying from 1.5 μm for the lowest nitriding temperature of 350 °C, to 30 μm for the highest nitriding temperature of 500 °C. The maximum Vickers microhardness of the γN phase layer with a peak nitrogen concentration of 20 at.% is about HV 0.1 N 15.1 GPa at the nitriding temperature of 450 °C. The wear and corrosion experimental results demonstrated that the γN phase was formed on the surface of AISI 316 austenitic stainless steel by plasma source nitriding, which exhibits not only high wear resistance, but also good pitting corrosion resistance.

  6. Improving electrochemical properties of AISI 1045 steels by duplex surface treatment of plasma nitriding and aluminizing

    Energy Technology Data Exchange (ETDEWEB)

    Haftlang, Farahnaz, E-mail: f.haftlang@students.semnan.ac.ir [Department of Metallurgy and Materials Engineering, Faculty of Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Habibolahzadeh, Ali [Department of Metallurgy and Materials Engineering, Faculty of Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Sohi, Mahmoud Heydarzadeh [School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2015-02-28

    Highlights: • AlN coating was applied on AISI 1045 steel via plasma nitriding and aluminizing. • Plasma nitriding and post-aluminizing result in AlN single phase layer on the steel. • PN–Al coated steel had better corrosion resistance than Al–PN one. • Formation of oxide layer provided protection of PN–Al coated steel against corrosion. • Pitting and surface defects was the dominant corrosion mechanism in Al–PN coated steel. - Abstract: Improvement in electrochemical behavior of AISI 1045 steel after applying aluminum nitride coating was investigated in 3.5% NaCl solution, using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) analyses. Aluminum nitride coating was applied on the steel surface by duplex treatment of pack aluminizing and plasma nitriding. Some specimens were plasma nitrided followed by aluminizing (PN–Al), while the others were pack aluminized followed by plasma nitriding (Al–PN). Topological and structural studies of the modified surfaces were conducted using scanning electron microscope (SEM) equipped by energy dispersive X-ray spectroscope (EDS), and X-ray diffractometer (XRD). The electrochemical measurements showed that the highest corrosion and polarization (R{sub p}) resistances were obtained in PN–Al specimens, having single phase superficial layer of AlN. Pitting mechanism was dominant reason of lower corrosion resistance in the Al–PN specimens.

  7. Improvement in cavitation erosion resistance of AISI 316L stainless steel by friction stir processing

    Energy Technology Data Exchange (ETDEWEB)

    Hajian, M. [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Abdollah-zadeh, A., E-mail: zadeh@modares.ac.ir [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Rezaei-Nejad, S.S.; Assadi, H. [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Hadavi, S.M.M. [Department of Materials Science and Engineering, MA University of Technology, Tehran (Iran, Islamic Republic of); Chung, K. [Department of Materials Science and Engineering, Research Institute of Advanced Materials, Engineering Research Institute, Seoul National University, Seoul (Korea, Republic of); Shokouhimehr, M. [Department of Chemical Engineering, College of Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2014-07-01

    Commercial AISI 316L plates with the initial grain size of 14.8 μm were friction stir processed (FSP) with different processing parameters, resulting in two fine-grained microstructures with the grain sizes of 4.6 and 1.7 μm. The cavitation erosion behavior, before and after FSP, was evaluated in terms of incubation time, cumulative mass loss and mean depth of erosion. A separate cavitation erosion test was performed on the transverse cross section of a FSP sample to reveal the effect of grain structure. It was observed that FSP samples, depending on their grain size, are at least 3–6 times more resistant than the base material against cavitation erosion. The improvement in cavitation erosion resistance is attributed to smaller grain structure, lower fraction of twin boundaries, and favorable crystallographic orientation of grains in FSP samples. The finer the grain size, the more cavitation erosion resistance was achieved. Moreover, the microstructures of eroded surfaces were studied using a scanning electron microscope equipped with EBSD, and an atomic force microscope. The mechanisms controlling the cavitation erosion damage in friction stir processed AISI 316L are also discussed.

  8. Dynamic strain ageing of deformed nitrogen-alloyed AISI 316 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Ehrnsten, U.; Toivonen, A. [Materials and Structural Integrity, VTT Technical Research Centre of Finland, Kemistintie 3, P.O. Box 1704, FIN-02044 VTT (Finland); Ivanchenko, M.; Nevdacha, V.; Yagozinskyy, Y.; Haenninen, H. [Department of Mechanical Engineering, Helsinki University of Technology Puumiehenkuja 3, P.O. Box 4200, FIN-02015 HUT (Finland)

    2004-07-01

    Intergranular stress corrosion cracking has occurred in BWR environment in non-sensitized, deformed austenitic stainless steel materials. The affecting parameters are so far not fully known, but deformation mechanisms may be decisive. The effect of deformation and nitrogen content on the behaviour of austenitic stainless steels was investigated. The materials were austenitic stainless steels of AISI 316L type with different amounts of nitrogen (0.03 - 0.18%) and they were mechanically deformed 0, 5 and 20%. The investigations are focused on the dynamic strain ageing (DSA) behaviour. A few crack growth rate measurements are performed on nuclear grade AISI 316NG material with different degrees of deformation (0, 5 and 20%). The effects of DSA on mechanical properties of these materials are evaluated based on peaks in ultimate tensile strength and strain hardening coefficient and minimum in ductility in the DSA temperature range. Additionally, internal friction measurements have been performed in the temperature range of -100 to 600 deg. C for determining nitrogen interactions with other alloying elements and dislocations (cold-worked samples). The results show an effect of nitrogen on the stainless steel behaviour, e.g. clear indications of dynamic strain ageing and changes in the internal friction peaks as a function of nitrogen content and amount of deformation. (authors)

  9. Evaluation of dynamic fracture mechanics in the AISI 316 stainless steel using instrumented Charpy impact testing

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Juliano Daniel de [Empresa Brasileira de Aeronautica S.A. (EMBRAER), Sao Jose dos Campos, SP (Brazil)]. E-mail: juliano.daniel@embraer.com.br; Rodrigues, Bruno Jardim Franca [Novo Nordisk, Montes Claros, MG (Brazil)]. E-mail: brro@novonordisk.com; Vilela, Jefferson Jose; Martins, Geraldo de Paula [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)]. E-mail: gpm@cdtn.br; Carneiro, Jose Rubens Goncalves [Pontificia Universidade Catolica de Minas Gerais (PUC Minas), Belo Horizonte, MG (Brazil)]. E-mail: joserub@pucminas.br

    2007-07-01

    The nuclear power plant's surveillance program is based in Charpy test. But, this test could be used to evaluate integrity's secondary circuit. The steel similar to AISI 316 stainless steel could be used in this circuit. Some secondary circuit's components could be failed in dynamic condition. The dynamic fracture mechanics behavior of the AISI 316 was studied by using instrumented Charpy impact testing. The dynamic fracture toughness (J{sub ld}) could be evaluated by four different methods: compliance changing rate, stretching zone, energy revised and maximum load energy. The tests were made in temperature -196 deg C, room and 200 deg C. At each temperature two specimens were tested. The impact energy was 300 J and the impact velocity was 5.12 m/s. The Charpy specimens 10 x 10 x 50 mm were pre-cracked until 5 mm according to ASTM E-23. Stretching zone size was measured and analyzed by observing the fracture surfaces that were obtained in a scanning electron microscope. The dynamic fracture toughness calculated among four different methods showed a large difference. All studied methods did not agree ASTM E1820 (2001) standard that indicated to plane strain did not occurred in the tip crack. (author)

  10. Improving by postoxidation of corrosion resistance of plasma nitrocarburized AISI 316 stainless steels

    Science.gov (United States)

    Yenilmez, A.; Karakan, M.; Çelik, İ.

    2017-01-01

    Austenitic stainless steels are widely used in several industries such as chemistry, food, health and space due to their perfect corrosion resistance. However, in addition to corrosion resistance, the mechanic and tribological features such as wear resistance and friction are required to be good in the production and engineering of this type of machines, equipment and mechanic parts. In this study, ferritic (FNC) and austenitic (ANC) nitrocarburizing were applied on AISI 316 stainless steel specimens with perfect corrosion resistance in the plasma environment at the definite time (4 h) and constant gas mixture atmosphere. In order to recover corrosion resistance which was deteriorated after nitrocarburizing again, plasma postoxidation process (45 min) was applied. After the duplex treatment, the specimens' structural analyses with XRD and SEM methods, corrosion analysis with polarization method and surface hardness with microhardness method were examined. At the end of the studies, AISI 316 surface hardness of stainless steel increased with nitrocarburizing process, but the corrosion resistance was deteriorated with FNC (570 °C) and ANC (670 °C) nitrocarburizing. With the following of the postoxidation treatment, it was detected that the corrosion resistance became better and it approached its value before the process.

  11. Determination of Proper Austenitization Temperatures for Hot Stamping of AISI 4140 Steel

    Science.gov (United States)

    Samadian, Pedram; Parsa, Mohammad Habibi; Shakeri, Amid

    2014-04-01

    High strength steels are desirable materials for use in automobile bodies in order to reduce vehicle weight and increase the safety of car passengers, but steel grades with high strength commonly show poor formability. Recently, steels with controlled microstructures and compositions are used to gain adequate strength after hot stamping while maintaining good formability during processing. In this study, microstructure evolutions and changes in mechanical properties of AISI 4140 steel sheets resulting from the hot stamping process at different austenitization temperatures were investigated. To determine the proper austenitization temperatures, the results were compared with those of the cold-worked and cold-worked plus quench-tempered specimens. Comparisons showed that the austenitization temperatures of 1000 and 1100 °C are proper for hot stamping of 3-mm-thick AISI 4140 steel sheets due to the resultant martensitic microstructure which led to the yield and ultimate tensile strength of 1.3 and 2.1 GPa, respectively. Such conditions resulted in more favorable simultaneous strength and elongation than those of hot-stamped conventional boron steels.

  12. PARAMETRIC STUDY OF ELECTRICAL DISCHARGE MACHINING OF AISI 304 STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    P. SRINIVASA RAO,

    2010-08-01

    Full Text Available Electrical discharge machining (EDM is widely used process in the production of mould / dies, aerospace, automobile and electronics industries where intricate complex shapes need to be machined in very hard materials. The selection of the AISI 304 stainless steel was made taking into account its use in almost all industrial applicationsfor approximately 50% of the world’s stainless steel production and consumption. In this work, a study has been carried out on the influence of four design factors: current, open-circuit voltage, servo and dutycycle over material removal rate, tool wear rate, surface roughness and hardness on the die-sinking electrical discharge machining of AISI 304 stainless steel. This has been done using design of experiments (DOE, which allows us to carry out theabove-mentioned analysis performing a relatively small number of experiments. In this case, a 3*24-1 mixed level factorial design, whose resolution is V, has been selected due to the number of factors considered in the study. The resolution of this mixed factorial design allows us to estimate all the main effects, two-factor interactions and pure quadratic effects of the four design factors selected to perform this study.

  13. Modeling of the flow stress for AISI H13 Tool Steel during Hard Machining Processes

    Science.gov (United States)

    Umbrello, Domenico; Rizzuti, Stefania; Outeiro, José C.; Shivpuri, Rajiv

    2007-04-01

    In general, the flow stress models used in computer simulation of machining processes are a function of effective strain, effective strain rate and temperature developed during the cutting process. However, these models do not adequately describe the material behavior in hard machining, where a range of material hardness between 45 and 60 HRC are used. Thus, depending on the specific material hardness different material models must be used in modeling the cutting process. This paper describes the development of a hardness-based flow stress and fracture models for the AISI H13 tool steel, which can be applied for range of material hardness mentioned above. These models were implemented in a non-isothermal viscoplastic numerical model to simulate the machining process for AISI H13 with various hardness values and applying different cutting regime parameters. Predicted results are validated by comparing them with experimental results found in the literature. They are found to predict reasonably well the cutting forces as well as the change in chip morphology from continuous to segmented chip as the material hardness change.

  14. Dependence of corrosion properties of AISI 304L stainless steel on the austenite grain size

    Energy Technology Data Exchange (ETDEWEB)

    Sabooni, Soheil; Rashtchi, Hamed; Eslami, Abdoulmajid; Karimzadeh, Fathallah; Enayati, Mohammad Hossein; Raeissi, Keyvan; Imani, Reihane Faghih [Isfahan Univ. of Technology, Isfahan (Iran, Islamic Republic of). Dept. of Materials Engineering; Ngan, Alfonso Hing Wan [The Univ. of Hong Kong (China). Dept. of Mechanical Engineering

    2017-07-15

    The corrosion resistance of austenitic stainless steels is known to be hampered by the loss of chromium available for passive surface layer formation as a result of chromium carbide precipitation at austenite grain boundaries during annealing treatments. Although high-temperature annealing can promote carbide dissolution leading to better corrosion resistance, grain coarsening also results, which would lead to poorer mechanical properties. Processing methods to achieve both good corrosion resistance and mechanical properties are thus highly desirable for austenitic stainless steels. In the present study, we show that the corrosion resistance of AISI 304L stainless steel can be improved by grain refinement into the ultrafine-grained regime. Specifically, samples with different austenite grain sizes in the range of 0.65-12 μm were studied by potentiodynamic polarization and electrochemical impedance spectroscopy tests in a 3.5 wt.% NaCl solution. All samples showed a typical passive behavior with similar corrosion potential, but the corrosion current density decreased significantly with decreasing grain size. The results show that the sample with the finest grain size had the best corrosion resistance due to a higher resistance of the passive layer to pitting attacks. This study indicates that grain refinement which improves mechanical properties can also significantly improve the corrosion resistance of AISI 304L stainless steel.

  15. Statistical regression modeling and machinability study of hardened AISI 52100 steel using cemented carbide insert

    Directory of Open Access Journals (Sweden)

    Amlana Panda

    2017-01-01

    Full Text Available The present study investigates performance and feasibility of application of low cost cemented carbide insert in dry machining of AISI 52100 steel hardened to (55 ± 1 HRC which is rarely researched as far as machining of bearing steel is concerned. Machinability studies i.e. flank wear, surface roughness and morphology analysis of chip has been investigated and statistical regression modeling has been developed. The test has been conducted based on Taguchi L16 OA taking machining parameters like cutting speed, feed and depth of cut. It is observed that uncoated cemented carbide insert performs well at some selected runs (Run 1, 5 and 9 which show its feasibility for hard turning applications. The developed serrated saw tooth chip of burnt blue colour adversely affects the surface quality. Adequacy of the developed statistical regression model has been checked using ANOVA analysis (depending on F value, P value and R2 value and normal probability plot at 95% confidence level. The results of optimal parametric combinations may be adopted while turning hardened AISI 52100 steel under dry environment with uncoated cemented carbide insert.

  16. Fit for purpose: Australia's National Fitness Campaign.

    Science.gov (United States)

    Collins, Julie A; Lekkas, Peter

    2011-12-19

    During a time of war, the federal government passed the National Fitness Act 1941 to improve the fitness of the youth of Australia and better prepare them for roles in the armed services and industry. Implementation of the National Fitness Act made federal funds available at a local level through state-based national fitness councils, which coordinated promotional campaigns, programs, education and infrastructure for physical fitness, with volunteers undertaking most of the work. Specifically focused on children and youth, national fitness councils supported the provision of children's playgrounds, youth clubs and school camping programs, as well as the development of physical education in schools and its teaching and research in universities. By the time the Act was repealed in 1994, fitness had become associated with leisure and recreation rather than being seen as equipping people for everyday life and work. The emergence of the Australian National Preventive Health Agency Act 2010 offers the opportunity to reflect on synergies with its historic precedent.

  17. Study on Apparent Viscosity and Structure of Foaming Slag

    Science.gov (United States)

    Martinsson, Johan; Glaser, Björn; Sichen, Du

    2016-10-01

    Foaming slag was generated using induction heating. The foam was found non-Newtonian having much higher apparent viscosity compared to the dynamic viscosity of pure slag. Quenched foam was examined. The appearance of the foaming slag was very different from silicone oil-gas foam. The size of gas bubbles ranged from 0.1 to 4 mm (while in the case of silicone oil, 1 to 2 mm). The gas fraction in the foam was considerably lower than in the case of silicone oil.

  18. New Approaches to Aluminum Integral Foam Production with Casting Methods

    Directory of Open Access Journals (Sweden)

    Ahmet Güner

    2015-08-01

    Full Text Available Integral foam has been used in the production of polymer materials for a long time. Metal integral foam casting systems are obtained by transferring and adapting polymer injection technology. Metal integral foam produced by casting has a solid skin at the surface and a foam core. Producing near-net shape reduces production expenses. Insurance companies nowadays want the automotive industry to use metallic foam parts because of their higher impact energy absorption properties. In this paper, manufacturing processes of aluminum integral foam with casting methods will be discussed.

  19. NON-AUTOCLAVE FOAM CONCRETE WITH MINERAL ADDITIVES

    Directory of Open Access Journals (Sweden)

    Екатерина Анатольевна Бартеньева

    2017-02-01

    Full Text Available The influence of mineral additives on the properties of technical foam and its physical and mechanical parameters of non-autoclave foam concrete. It is determined that the introduction in its composition of 1% wollastonite and diopside to reduce the density of finished products, to increase their strength. Thus, there is improvement in the foam stability coefficient in the cement paste, increases its multiplicity. This highly dispersed mineral additives can be used as foam and plastics foam concrete stabilizers. The injection of researched additives allows to obtain the insulating foam with a stable space-frame structure.

  20. Compressive properties of open-cell ceramic foams

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-yan; FU Yi-ming; ZENG Xiao-ming

    2006-01-01

    The compressive experiments of two kinds of ceramic foams were completed. The results show that the behavior of ceramic foams made by organic filling method is anisotropic. The stress-strain responses of ceramic foams made by sponge-replication show isotropy and strain rate dependence. The struts brittle breaking of net structure of this ceramic foam arises at the weakest defects of framework or at the part of framework,which causes the initiation and expanding of cracks. The compressive strength of ceramic foam is dependent on the strut size and relative density of foams.

  1. In-situ investigation of martensite formation in AISI 52100 bearing steel at sub-zero Celsius temperature

    DEFF Research Database (Denmark)

    Villa, Matteo; Hansen, Mikkel Fougt; Pantleon, Karen

    2013-01-01

    Martensite formation in AISI 52100 bearing steel at sub-zero Celsius temperature was investigated with Vibrating Sample Magnetometry. The investigation reports the stabilization of retained austenite in quenched samples during storage at room temperature and reveals the thermally activated nature...

  2. Extended X-Ray Absorption Fine Structure Investigation of Carbon Stabilized Expanded Austenite and Carbides in Stainless Steel AISI 316

    DEFF Research Database (Denmark)

    Oddershede, Jette; Christiansen, Thomas; Ståhl, Kenny;

    2011-01-01

    Low temperature carburized AISI 316 stainless steel - carbon expanded austenite - was investigated with EXAFS and synchrotron diffraction together with synthesized carbides of the type M3C2, M7C3 and M23C6. It was found that the chemical environment of carbon expanded austenite is not associated ...

  3. The effect of cladding speed on phase constitution and properties of AISI 431 stainless steel laser deposited coatings

    NARCIS (Netherlands)

    Hemmati, I.; Ocelik, V.; De Hosson, J. Th. M.

    2011-01-01

    Shorter processing time has given impetus to laser cladding technology and therefore in this research the AISI 431 martensitic stainless steel coatings are laser deposited at high cladding speeds, i.e. up to 117 mm/s. The analysis of phase constitution and functional properties of the coatings are p

  4. Surface fatigue life and failure characteristics of EX-53, CBS 1000M, and AISI 9310 gear materials

    Science.gov (United States)

    Townsend, D. P.

    1985-01-01

    Spur gear endurance tests and rolling-element surface fatigue tests are conducted to investigate EX-53 and CBS 1000M steels for use as advanced application gear materials, to determine their endurance characteristics, and to compare the results with the standard AISI 9310 gear material. The gear pitch diameter is 8.89 cm (3.50 in). Gear test conditions are an oil inlet temperature of 320 K (116 F), an oil outlet temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. Bench-type rolling-element fatigue tests are conducted at ambient temperature with a bar specimen speed of 12,500 rpm and a maximum Hertz stress of 4.83 GPa (700 ksi). The EX-53 test gears have a surface fatigue life of twice that of the AISI 9310 spur gears. The CBS 1000M test gears have a surface fatigue life of more than twice that of the AISI 9310 spur gears. However, the CBS 1000M gears experience a 30-percent tooth fracture failure which limits its use as a gear material. The rolling-contact fatigue lines of RC bar specimens of EX-53 and ASISI 9310 are approximately equal. However, the CBS 1000M RC specimens have a surface fatigue life of about 50 percent that of the AISI 9310.

  5. Dynamic Behavior of Hybrid APM (Advanced Pore Morphology Foam and Aluminum Foam Filled Structures

    Directory of Open Access Journals (Sweden)

    Joerg Weise

    2012-06-01

    Full Text Available The aim of this work is to evaluate the effect of different densities of hybrid aluminum polymer foam on the frequency behavior of a foam filled steel structure with different ratios between steel and foam masses. The foam filled structure is composed of three steel tubes with a welded flange at both ends bolted together to form a portal grounded by its free ends. Structure, internal and ground constraints have been designed and manufactured in order to minimize nonlinear effects and to guarantee optimal constraint conditions. Mode shapes and frequencies were verified with finite elements models (FEM to be in the range of experimental modal analysis, considering the frequency measurement range limits for instrumented hammer and accelerometer. Selected modes have been identified with suitable modal parameters extraction techniques. Each structure has been tested before and after filling, in order to compute the percentage variation of modal parameters. Two different densities of hybrid aluminum polymer foam have been tested and compared with structures filled with aluminum foams produced using the powder compact melting technique. All the foam fillings were able to suppress high frequency membrane modes which results in a reduction of environmental noise and an increase in performance of the components. Low frequency modes show an increase in damping ratio only when small thickness steel frames are filled with either Hybrid APM or Alulight foam.

  6. 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

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

    NARCIS (Netherlands)

    Vancso, G.J.; Duvigneau, J.; 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

  8. Microstructure and Electrical Conductivity of CNTs/PMMA Nanocomposite Foams Foaming by Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    YUAN Huan; XIONG Yuanlu; LUO Guoqiang; LI Meijuan; SHEN Qiang; ZHANG Lianmeng

    2016-01-01

    The carbon nanotubes (CNTs)/ polymethylmethacrylate (PMMA) nanocomposite foams were prepared by the anti-solvent precipitation and supercritical foaming method. The morphology and the electrical conductivity of the foams with different kinds of CNTs were investigated. The experimental results showed that all the foams had uniform cell structure, and the cell size changed from 1.9 to 10 μm when the foaming temperature ranged from 50℃ to 95℃. With small cell size (1.9-4.0 μm), the conductivities of the foams were 3.34×10-6-4.16×10-6 S/cm compared with the solid matrix since the introduction of micro cells did not destroy the conductive network. However, when the cell size was biger (4.5-10 μm), the aspect ratio of the CNTs played the dominant role of the conductivity. The foams with short CNTs had higher conductivity, since the short CNTs were hard to stretch and snap by the cells and can well-dispersed in the cell wall and cell edges. The results of this work provided a novel material design method for conductive foams based on the rule of both microstructure and aspect ratio of the CNTs.

  9. Effect of surface modification of silica nanoparticles on foam stability in decontamination foam

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

    Decontamination foam is a non-stable, two-phase fluid with aqueous and gas phases representing not more than 10% and 90% of the total volume, respectively. This formulation can significantly decrease the amounts of chemical reagents and secondary waste. The advantage of decontamination foam is its potentially wide application for metallic walls, overhead surfaces, and the elements of complex components and facilities. In addition, the application of foam allows for remote decontamination processing using only an injection nozzle and the equipment to generate the decontamination foam, which reduces operator exposure to high radioactivity. Solid colloidal particles increase the foam stability in the foam formulation. These particles can be specifically hydrophobized for optimal adsorption at the liquid/gas interface, which creates armor for the bubbles and prevents coalescence by reducing the internal gas transfer. Conversely, hydrophilic particles remain confined in the liquid phase, and to enhance the foam stability. In this study, we aimed to modify the surface of silica nanoparticles with dichlorodimethylsilane (DCDMS) reagents using methods proposed in previous literatures. We plan to investigate further the influence pH and the concentration of chemical reagent in decontamination foam system. In future studies, decontamination tests will be conducted on a surface contaminated with radionuclides such as cesium and cobalt.

  10. A new adding method of foaming agent used for foam dust suppression in underground coal mines

    Institute of Scientific and Technical Information of China (English)

    陆新晓; 沈威; 王德明; 仲晓星; 朱朝炳; 徐超航

    2015-01-01

    To realize a stable addition of foaming agent used for foam technology, a new adding method using the jet cavitation was introduced, and its performance was investigated experimentally under different operating conditions. Experimental results show that the bubble region in the jet device has a constant vapor pressure, which creates a good condition for liquid absorption, while it shrinks with increasing outlet pressure. The liquid absorption amount keeps unchanged when the outlet pressure is lower than a critical value. The critical outlet pressure increases by 40% with decreasing cavitation absorption amount, which is especially suitable for mini-flow quantitative addition of foaming agent used for foam dust suppression. Its effectiveness on suppressing mine dust was evaluated in a heading face of underground coal mines. Field application indicates that the reliable and simple foaming system adopting the new adding method makes a marked dust suppression effect. The working environment of heading face is significantly improved, ensuring the safe tunneling and personal security.

  11. Effect of starch particles on foam stability and dilational viscoelasticity of aqueous-foam

    Institute of Scientific and Technical Information of China (English)

    Yongqiang Zhang; Zhidong Chang; Wenli Luo; Shaonan Gu; Wenjun Li; Jianbo An

    2015-01-01

    Surface dilational rheological behavior and foam stability of starch/surfactant mixed solutions were studied at differ-ent starch concentrations and constant surfactant concentration. The results show that dilational viscoelasticity modulus, dilational elasticity modulus and dilational viscosity modulus increase with the concentration of starch particles. Foam stability increases with dilational viscoelasticity. Foam strength also increases with starch concentra-tion. Starch particles play a positive effect on foam stability and dilational viscoelasticity and the effect becomes more significant as drainage proceeds. Film pictures indicate that the film with 20%(by mass) starch particles is thicker than that without starch. Starch particles gather in Plateau border and resist drainage, making the foam more stable. © 2014 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. Al rights reserved.

  12. Influence of Conditions of Preparing the Foamed Plaster on its Degree of Foaming

    Directory of Open Access Journals (Sweden)

    M. Pawlak

    2007-07-01

    Full Text Available Foamed plaster moulds are used in precision casting process of non-ferrous alloys. Casting from those moulds are characterizedby high dimensional accuracy, very good shape pattering and small surface roughness. However, a drawback of the plaster mould is very low permeability. A substational improvement of this parametr may be achived through physical or phisico-chemical treatment of the plaster slurry or prepared mould. The most advantageous results can be obtained by foaming the slurry. The investigatious comprised evaluation of the influence of mixing parametrs (mixer type, rotation and mixing time, settings the mixer in mixing device and the content of a foaming agent on the degree of foaming of the plaster. The tests were carried out using the α-plaster Hartform-H1 and Alkanol XC as a foaming agent. The structure of a slurry produced after foaming is non-homogeous. Therefore, the investigations were completed by making appropriate of this process. Analysis of the results leads to the conclusion, that the foamed plaster Hartform_H1 reaches the top degree of foaming at the following parameters: the water/plaster ratio W/G=0.55, the content of Alkanol XC a=0.07%, stirring with a perforate disc mixer at the rotation speed nm=4000 rpm during τm=30 s. In turn the top homogeneity of the foamed plaster slurry can be achieved at the rotation speed nu=1400 rpm during τu=30 s., while other parameters are the same as in the foaming process. The obtained results can provide the basis for the elaboration of the industry procedures useful in the production of the plaster moulds for precision casting.

  13. Evaluation of a steady-state test of foam stability

    Science.gov (United States)

    Hutzler, Stefan; Lösch, Dörte; Carey, Enda; Weaire, Denis; Hloucha, Matthias; Stubenrauch, Cosima

    2011-02-01

    We have evaluated a steady-state test of foam stability, based on the steady-state height of a foam produced by a constant velocity of gas flow. This test is mentioned in the book by Bikerman [Foams, Springer, Berlin, 1973] and an elementary theory was developed for it by Verbist et al. [J. Phys. Condens. Matter 8 (1996) p. 3715]. For the study, we used an aqueous solution of the cationic surfactant dodecyl trimethylammonium bromide, C12TAB, at a concentration of two times the critical micelle concentration (2 cmc). During foam generation, bubbles collapse at the top of the column which, in turn, eventually counterbalances the rate of bubble production at the bottom. The resulting balance can be described mathematically by an appropriate solution of the foam drainage equation under specified boundary conditions. Our experimental findings are in agreement with the theoretical predictions of a diverging foam height at a critical gas velocity and a finite foam height in the limit of zero velocity. We identify a critical liquid fraction below which a foam is unstable as an important parameter for characterizing foam stability. Furthermore, we deduce an effective viscosity of the liquid which flows through the foam. Currently unexplained are two experimental observations, namely sudden changes of the steady-state foam height in experiments that run over several hours and a reduction in foam height once an overflow of the foam from the containing vessel has occurred.

  14. Damping capacity and compressive characteristic in some aluminum foams

    Institute of Scientific and Technical Information of China (English)

    程和法; 黄笑梅; 魏建宁; 韩福生

    2003-01-01

    The compressive behavior, energy absorption and damping capacity of Al-28% Zn alloy foam, Al-10% Mg alloy foam and commercial pure aluminum foam with open cell were investigated. The Al-28 % Zn alloy foam exhibits the typical deformation behavior of brittle foam in static compression, and a much higher energy absorption capacity than the Al-10%Mg alloy foam and pure aluminum foam to the densification strain. Over a large plastic strain range, the energy absorption efficiency of the Al-28 % Zn alloy foam keeps nearly constant and above 80%. The experiments on the internal friction of the three foams are also conducted on a multifunction internal friction apparatus (MFIFA). The Al-28%Zn alloy foam exhibits a high damping capacity which is three to four times larger than those of the pure aluminum foam and Al-28%Mg alloy foam around room temperature. The mechanism for the high damping capacity of the foamed Al-28%Zn alloy may be associated with the viscous sliding at the interface between the soft phase α and the brittle rich Zn phase η in its base metal during vibration.

  15. ProFit: Bayesian galaxy fitting tool

    Science.gov (United States)

    Robotham, A. S. G.; Taranu, D.; Tobar, R.

    2016-12-01

    ProFit is a Bayesian galaxy fitting tool that uses the fast C++ image generation library libprofit (ascl:1612.003) and a flexible R interface to a large number of likelihood samplers. It offers a fully featured Bayesian interface to galaxy model fitting (also called profiling), using mostly the same standard inputs as other popular codes (e.g. GALFIT ascl:1104.010), but it is also able to use complex priors and a number of likelihoods.

  16. A Pretty Good Fit

    Science.gov (United States)

    Erickson, Tim

    2008-01-01

    We often look for a best-fit function to a set of data. This article describes how a "pretty good" fit might be better than a "best" fit when it comes to promoting conceptual understanding of functions. In a pretty good fit, students design the function themselves rather than choosing it from a menu; they use appropriate variable names; and they…

  17. Unge, sundhed og fitness

    DEFF Research Database (Denmark)

    Jensen, Jens-Ole

    2003-01-01

    Artiklen redegør for udbredelsen af fitness blandt unge og diskuterer, hvor det er blevet så populært at dyrke fitness.......Artiklen redegør for udbredelsen af fitness blandt unge og diskuterer, hvor det er blevet så populært at dyrke fitness....

  18. 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...

  19. Compact assembly generates plastic foam, inflates flotation bag

    Science.gov (United States)

    1965-01-01

    Device for generating plastic foam consists of an elastomeric bag and two containers with liquid resin and a liquid catalyst. When the walls of the containers are ruptured the liquids come into contact producing foam which inflates the elastomeric bag.

  20. Microbial analysis in biogas reactors suffering by foaming incidents.

    Science.gov (United States)

    Kougias, Panagiotis G; De Francisci, Davide; Treu, Laura; Campanaro, Stefano; Angelidaki, Irini

    2014-09-01

    Foam formation can lead to total failure of digestion process in biogas plants. In the present study, possible correlation between foaming and the presence of specific microorganisms in biogas reactors was elucidated. The microbial ecology of continuous fed digesters overloaded with proteins, lipids and carbohydrates before and after foaming incidents was characterized using 16S rRNA gene sequencing. Moreover, the microbial diversity between the liquid and foaming layer was assessed. A number of genera that are known to produce biosurfactants, contain mycolic acid in their cell wall, or decrease the surface tension of the media, increased their relative abundance after foam formation. Finally, a microorganism similar to widely known foaming bacteria (Nocardia and Desulfotomaculum) was found to increase its relative abundance in all reactors once foam was observed, regardless of the used substrate. These findings suggest that foaming and specific microorganisms might have direct association which requires to be further investigated.

  1. New Flexible FR Polyurethane Foams for Energy Absorption Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of new polyurethane (PU) insulation foams through a non-toxic environmentally friendly composite approach. Target FR foams will exhibit high heat flow...

  2. Mechanical Properties of Electrolyte Jet Electrodeposited Nickel Foam

    Directory of Open Access Journals (Sweden)

    Jinsong Chen

    2013-07-01

    Full Text Available Principles of the preparation of nickel foam by electrolyte jet electrodeposition were introduced, Nickel foam samples with different porosity were fabricated. Effect of different porosity on microhardness and uniaxial tensile properties of nickel foam was discussed. The results show that the microhardness of nickel foam is 320~400 HV, lower than entitative metal clearly. The lower the porosity of nickel foam, the higher the microhardness is. During the process of uniaxial tensile, nickel foam is characterized by three distinct regions, e.g. elastic deforming region, plastic plateau region and densification region. The higher the porosity of nickel foam, the lower the plastic plateau and the poorer the strength of nickel foam, accordingly

  3. New Flexible FR Polyurethane Foams for Energy Absorption Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Project involves development of new flexible FR polyurethane (PU)insulation foams through a non-toxic environmentally friendly composite approach. Foams have...

  4. METHODS OF REDUCTION OF FREE PHENOL CONTENT IN PHENOLIC FOAM

    Directory of Open Access Journals (Sweden)

    Bruyako Mikhail Gerasimovich

    2012-12-01

    method aimed at reduction of toxicity of phenolic foams consists in the introduction of a composite mixture of chelate compounds. Raw materials applied in the production of phenolic foams include polymers FRB-1A and VAG-3. The aforementioned materials are used to produce foams FRP-1. Introduction of 1% aluminum fluoride leads to the 40% reduction of the free phenol content in the foam. Introduction of crystalline zinc chloride accelerates the foaming and curing of phenolic foams. The technology that contemplates the introduction of zeolites into the mixture includes pre-mixing with FRB -1A and subsequent mixing with VAG-3; thereafter, the composition is poured into the form, in which the process of foaming is initiated. The content of free phenol was identified using the method of UV spectroscopy. The objective of the research was to develop methods of reduction of the free phenol content in the phenolic foam.

  5. Shape recovery of PET foams after cold compression

    Science.gov (United States)

    Santo, Loredana; Bellisario, Denise; Quadrini, Fabrizio

    2016-10-01

    In this study, the recovery properties of thermoplastic foam are discussed. The feasibility of using this foam as core for the production of a shape memory sandwich with self-repairing properties is evaluated. PET foams have been extracted from a panel of PET foam in order to test the foam in the three space directions. Small cubic samples were then subjected to memory-recovery cycle. This cycle consisted of a cold compression to reduce the foam sample thickness up to 50%, and a subsequent recovery of the shape by heating the samples in a muffle. This way, it was possible to evaluate the effect of anisotropy on strength, stiffness and shape recovery of the PET foam. Afterwards, compression tests have been repeated to evaluate residual properties of PET foam after cold compression and hot recovery. Results confirm the ability of this class of materials to easily change and recovery their shape.

  6. Rheology of Foam Near the Order-Disorder Phase Transition

    Science.gov (United States)

    Holt, R. Glynn; McDaniel, J. Gregory

    1999-01-01

    Foams are extremely important in a variety of industrial applications. Foams are widely used in fire-fighting applications, and are especially effective in fighting flammable liquid fires. In fact the Fire Suppression System aboard the Space Shuttle utilizes cylinders of Halon foam, which, when fired, force a rapidly expanding foam into the convoluted spaces behind instrument panels. Foams are critical in the process of enhanced oil recovery, due to their surface-active and highly viscous nature. They are also used as drilling fluids in underpressurized geologic formations. They are used as transport agents, and as trapping agents. They are also used as separation agents, where ore refinement is accomplished by froth flotation of the typically lighter and hydrophobic contaminants. The goal of the proposed investigation is the determination of the mechanical and rheological properties of foams, utilizing the microgravity environment to explore foam rheology for foams which cannot exist, or only exist for a short time, in 1g.

  7. Auxetic polyurethane foam: Manufacturing and processing analysis

    Science.gov (United States)

    Jahan, Md Deloyer

    Materials with negative Poisson's ratio are referred to as auxetic materials. They are different from conventional materials in their deformation behavior when responding to external stresses. The cross-section of the materials widens in the lateral direction when being stretched in the longitudinal direction and becomes narrower when being compressed longitudinally. While a number of natural auxetic materials exist, most auxetic materials are synthetic. They show interesting properties and have potential in several important applications. Auxetic materials exhibit better mechanical properties than conventional materials such as enhanced indentation resistance, shear resistance, toughness, damping and energy absorption capacity, sound absorption, variable permeability and capability of producing complex curvature. These properties are beneficial in a wide range of applications including personal protective equipments, sound absorbers, packaging, smart filtration, drug delivery, tissue scaffolding, seat cushioning, etc. A wide range of auxetic materials has been synthesized. They include different polymers, metals, composites and ceramics. Among these, auxetic polyurethane (PU) foam is one of the most widely studied types of auxetic materials. Auxetic PU foams are usually fabricated by altering the microstructure of conventional foams and the unusual mechanical properties originate from the deformation characteristics of the microstructures. Three most important processing parameters in fabricating auxetic PU foam that dictate auxetic behavior are processing temperature, heating time and volumetric compression ratio. This study addresses several important issues in the manufacturing and characterization of auxetic PU foam. First, an improved automatic measuring technique has been developed to determine Poisson's ratio of auxetic PU foam. The technique involves development of a Matlab based image processing program. The second part of the study includes an

  8. Fire-Induced Response in Foam Encapsulants

    Energy Technology Data Exchange (ETDEWEB)

    Borek, T.T.; Chu, T.Y.; Erickson, K.L.; Gill, W.; Hobbs, M.L.; Humphries, L.L.; Renlund, A.M.; Ulibarri, T.A.

    1999-04-02

    The paper provides a concise overview of a coordinated experimental/theoretical/numerical program at Sandia National Laboratories to develop an experimentally validated model of fire-induced response of foam-filled engineered systems for nuclear and transportation safety applications. Integral experiments are performed to investigate the thermal response of polyurethane foam-filled systems exposed to fire-like heat fluxes. A suite of laboratory experiments is performed to characterize the decomposition chemistry of polyurethane. Mass loss and energy associated with foam decomposition and chemical structures of the virgin and decomposed foam are determined. Decomposition chemistry is modeled as the degradation of macromolecular structures by bond breaking followed by vaporization of small fragments of the macromolecule with high vapor pressures. The chemical decomposition model is validated against the laboratory data. Data from integral experiments is used to assess and validate a FEM foam thermal response model with the chemistry model developed from the decomposition experiments. Good agreement was achieved both in the progression of the decomposition front and the in-depth thermal response.

  9. Development of multifunctional shape memory polymer foams

    Science.gov (United States)

    Song, Janice J.; Srivastava, Ijya; Naguib, Hani E.

    2015-05-01

    Shape memory polymers (SMP) are a class of stimuli-responsive materials which are able to respond to external stimulus such as temperature and deformation by changing their shape, and return to their original shape upon reversal or removal of the external stimulus. Although SMP materials have been studied extensively and have been used in a wide range of applications such as medicine, aerospace, and robotics, only few studies have looked at the potential of designing multifunctional SMP foams and blends. In this study, we investigate the feasibility of a design of SMP foam materials and blends. The actuator construct will contain a core SMP epoxy and blend of polylactic acid and polyurethane. The effects of the processing parameters of shape memory polymer (SMP) foams on the shape memory effect (SME) were investigated. The solid state foaming technique was employed to obtain the desired foamed cellular structure. One particular point of interest is to understand how the processing parameters affect the SMP and its glass transition temperature (Tg). By correctly tailoring these parameters it is possible to modify the SMP to have an improved shape memory effect SME.

  10. Purely geometric path integral for spin foams

    CERN Document Server

    Shirazi, Atousa Chaharsough

    2013-01-01

    Spin-foams are a proposal for defining the dynamics of loop quantum gravity via path integral. In order for a path integral to be at least formally equivalent to the corresponding canonical quantization, at each point in the space of histories it is important that the integrand have not only the correct phase -- a topic of recent focus in spin-foams -- but also the correct modulus, usually referred to as the measure factor. The correct measure factor descends from the Liouville measure on the reduced phase space, and its calculation is a task of canonical analysis. The covariant formulation of gravity from which spin-foams are derived is the Plebanski-Holst formulation, in which the basic variables are a Lorentz connection and a Lorentz-algebra valued two-form, called the Plebanski two-form. However, in the final spin-foam sum, one sums over only spins and intertwiners, which label eigenstates of the Plebanski two-form alone. The spin-foam sum is therefore a discretized version of a Plebanski-Holst path integ...

  11. Headspace analysis of foams and fixatives

    Energy Technology Data Exchange (ETDEWEB)

    Harper, Kyle [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Truong, Thanh-Tam [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Magwood, Leroy [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Peters, Brent [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Nicholson, James [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-07-27

    In the process of decontaminating and decommissioning (D&D) older nuclear facilities, special precautions must be taken with removable or airborne contamination. One possible strategy utilizes foams and fixatives to affix these loose contaminants. Many foams and fixatives are already commercially available, either generically or sold specifically for D&D. However, due to a lack of revelant testing in a radioactive environment, additional verification is needed to confirm that these products not only affix contamination to their surfaces, but also will function in a D&D environment. Several significant safety factors, including flammability and worker safety, can be analyzed through the process of headspace analysis, a technique that analyzes the off gas formed before or during the curing process of the foam/fixative, usually using gas chromatography-mass spectrometry (GC-MS). This process focuses on the volatile components of a chemical, which move freely between the solid/liquid form within the sample and the gaseous form in the area above the sample (the headspace). Between possibly hot conditions in a D&D situation and heat created in a foaming reaction, the volatility of many chemicals can change, and thus different gasses can be released at different times throughout the reaction. This project focused on analysis of volatile chemicals involved in the process of using foams and fixatives to identify any potential hazardous or flammable compounds.

  12. Stability of minoxidil in Espumil foam base.

    Science.gov (United States)

    Geiger, Christine M; Sorenson, Bridget; Whaley, Paul A

    2013-01-01

    Minoxidil is a drug used to stimulate hair growth and to slow balding. It is marketed under a number of trade names, including Rogaine, and is available in varying strength dose forms from a number of generic manufacturers. Minoxidil is available in oral and topical forms. In topical form, it can be applied by a metered-spray or rub-on applicator. A hydroalcoholic compounding vehicle can minimize greasiness, itching, burning, and contact dermatitis where low concentrations of ethanol and propylene glycol are present. Espumil Foam Base contains low concentrations of these ingredients and also can form a foam on topical application. Espumil's unique delivery by foam-activating packaging assures simple application to difficult-to-treat areas, and it vanishes quickly after application, keeping it in place and avoiding health skin areas. The objective of this study was to determine the stability of minoxidil in Espumil Foam Base. The studied sample was compounded into a 50-mg/mL solution and stored in a plastic foam-activating bottle at room temperature conditions. Three samples were assayed at each time point out to 90 days by a stability-indicating high-performance liquid chromatography method. The method was validated for its specificity through forced-degradation studies. The beyond-use-date is at least 90 days, based on data collected when this formulation was stored at room temperature, protected from light.

  13. Styrene-based shape memory foam: fabrication and mathematical modeling

    Science.gov (United States)

    Yao, Yongtao; Zhou, Tianyang; Qin, Chao; Liu, Yanju; Leng, Jinsong

    2016-10-01

    Shape memory polymer foam is a promising kind of structure in the biomedical and aerospace field. Shape memory styrene foam with uniform and controlled open-cell structure was successfully fabricated using a salt particulate leaching method. Shape recovery capability exists for foam programming in both high-temperature compression and low-temperature compression (Ashby as well as differential micromechanics theory were applied to predict Young’s modulus and the mechanical behavior of SMP styrene foams during the compression process.

  14. Fitness World - Fremtidig overlevelse

    OpenAIRE

    Rice, Kasper; Klink, Nikolaj; Nielsen, Mie; Carlson, Andre; Boy, Mikkel; Hansen, Alexander

    2015-01-01

    Our project is a case study with Fitness World as a baseline. Our project will enhance Fitness Worlds penetration on their current position on the market. Our empiricism includes both qualitative and quantitative methodical approaches by the use of an expert interview and a questionnaire survey. These methods contribute and generate general knowledge about the fitness culture in Denmark and the customers in the fitness industry. We have stated a possible strategic opportunity for Fitness Worl...

  15. Comparing Acute Bouts of Sagittal Plane Progression Foam Rolling vs. Frontal Plane Progression Foam Rolling.

    Science.gov (United States)

    Peacock, Corey A; Krein, Darren D; Antonio, Jose; Sanders, Gabriel J; Silver, Tobin A; Colas, Megan

    2015-08-01

    Many strength and conditioning professionals have included the use of foam rolling devices within a warm-up routine prior to both training and competition. Multiple studies have investigated foam rolling in regards to performance, flexibility, and rehabilitation; however, additional research is necessary in supporting the topic. Furthermore, as multiple foam rolling progressions exist, researching differences that may result from each is required. To investigate differences in foam rolling progressions, 16 athletically trained males underwent a 2-condition within-subjects protocol comparing the differences of 2 common foam rolling progressions in regards to performance testing. The 2 conditions included a foam rolling progression targeting the mediolateral axis of the body (FRml) and foam rolling progression targeting the anteroposterior axis (FRap). Each was administered in adjunct with a full-body dynamic warm-up. After each rolling progression, subjects performed National Football League combine drills, flexibility, and subjective scaling measures. The data demonstrated that FRml was effective at improving flexibility (p ≤ 0.05) when compared with FRap. No other differences existed between progressions.

  16. The Role of Foaming Agent and Processing Route in Mechanical Performance of Fabricated Aluminum Foams

    Directory of Open Access Journals (Sweden)

    Alexandra Byakova

    2014-01-01

    Full Text Available The results of this study highlight the role of foaming agent and processing route in influencing the contamination of cell wall material by side products, which, in turn, affects the macroscopic mechanical response of closed-cell Al-foams. Several kinds of Al-foams have been produced with pure Al/Al-alloys by the Alporas like melt process, all performed with and without Ca additive and processed either with conventional TiH2 foaming agent or CaCO3 as an alternative one. Damage behavior of contaminations was believed to affect the micromechanism of foam deformation, favoring either plastic buckling or brittle failure of cell walls. No discrepancy between experimental values of compressive strengths for Al-foams comprising ductile cell wall constituents and those prescribed by theoretical models for closed-cell structure was found while the presence of low ductile and/or brittle eutectic domains and contaminations including particles/layers of Al3Ti, residues of partially reacted TiH2, and Ca bearing compounds, results in reducing the compressive strength to values close to or even below those of open-cell foams of the same relative density.

  17. The Role of Foaming Agent and Processing Route in the Mechanical Performance of Fabricated Aluminum Foams

    Directory of Open Access Journals (Sweden)

    Takashi Nakamura

    2012-05-01

    Full Text Available The results of the present study highlight the role of foaming agent and processing route in influencing the contamination of cell wall material by side products, which, in turn, affect the macroscopic mechanical response of closed-cell Al-foams. Several kinds of Al-foams have been produced with pure Al by the Alporas melt process and powder metallurgical technique, all performed either with conventional TiH2 foaming agent or CaCO3 as an alternative. Mechanical characteristics of contaminating products induced by processing additives, all of which were presented in one or another kind of Al-foam, have been determined in indentation experiments. Damage behavior of these contaminations affects the micro-mechanism of deformation and favors either plastic buckling or brittle failure of the cell walls. It is justified that there is no discrepancy between experimental values of compressive strengths for Al-foams comprising ductile Al + Al4Ca eutectic domains and those prescribed by theoretical models for closed-cell structure. However, the presence of low ductile Al + Al3Ti + Al4Ca eutectic domains and brittle particles/layers of Al3Ti, fine CaCO3/CaO particles, Al2O3 oxide network, and, especially, residues of partially reacted TiH2, results in reducing the compressive strength to values close to or even below those of open-cell foams of the same relative density.

  18. Preparation of Aluminum Foam Sandwich by Rolling-bonding/Powder Metallurgy Foaming Technology

    Institute of Scientific and Technical Information of China (English)

    ZU Guoyin; SONG Binna; GUAN Zhihao; WANG Lei; YAO Guangchun

    2011-01-01

    Aluminum foam sandwich was prepared by rolling-bonding/powder metallurgical foaming technology,and the effects of rolling on bond strength of face sheet/powders and powder density were studied.Moreover,the foaming agent,TiH2,was heat treated and a certain amount of Mg was added into powder in an attempt to understand how the stability and uniformity of foam was improved.The experimental results show that the foaming precursors with ideal quality were obtained by rolling-bonding process.When rolling reduction is 67%,the consistency of powders reach to 99.87%.Throughout consideration of the bonding of face sheet/core layer powders and deformation characteristic of powders,the optimum rolling reduction is 60%-70%.Cracks and drainage during foaming were inhibited by heat treatment of foaming agent TiH2 and the addition of a certain amount of Mg.The optimum heat treatment way of TiH2 is that heat preserving 1 hour at 450 ℃;the amount of adding Mg is 1wt%.

  19. Resistencia al desgaste de recubrimientos Fe-Nb-Cr-W, Nb, AISI 1020 y AISI 420 producidos por proyección térmica por arco eléctrico

    Directory of Open Access Journals (Sweden)

    López-Covaleda, E. A.

    2013-10-01

    Full Text Available The commercial materials 140MXC (with iron, tungsten, chrome, niobium, 530AS (AISI 1015 steel and 560AS (AISI 420 steel on AISI 4340 steel were deposited using thermal spray with arc. The aim of work was to evaluate the best strategy abrasive wear resistance of the system coating-substrate using the following combinations: (1 homogeneous coatings and (2 coatings depositing simultaneously 140MXC + 530AS and 140MXC + 560AS. The coatings microstructure was characterized using Optical microscopy, Scanning electron microscopy and Laser confocal microscopy. The wear resistance was evaluated through dry sand rubber wheel test (DSRW. We found that the wear resistance depends on the quantity of defects and the mechanical properties like hardness. For example, the softer coatings have the biggest wear rates and the failure mode was characterized by plastic deformation caused by particles indentation, and the other hand the failure mode at the harder materials was grooving. The details and wear mechanism of the coatings produced are described in this investigation.Mediante proyección térmica de arco eléctrico fueron depositados tres materiales comercialmente conocidos como: 140MXC (a base de hierro, wolframio, cromo y niobio, 530AS (acero AISI 1020 y 560AS (acero AISI 420, sobre acero AISI 4340. Con el objetivo de evaluar la mejor estrategia para incrementar la resistencia al desgaste abrasivo, los recubrimientos fueron depositados de dos formas: (1 monocapas homogéneas de cada material y (2 recubrimientos depositando con alambres disimiles de 140MXC + 530AS y 140MXC + 560AS. Los recubrimientos fueron caracterizados microestructuralmente mediante Difracción de rayos X, Microscopía óptica, Microscopía láser confocal y Microscopía electrónica de barrido. La evaluación de la resistencia al desgaste abrasivo se realizó mediante ensayo con arena seca y rueda de caucho (DSRW. Se encontró que la resistencia al desgaste depende entre otras de las

  20. Understanding about How Different Foaming Gases Effect the Interfacial Array Behaviors of Surfactants and the Foam Properties.

    Science.gov (United States)

    Sun, Yange; Qi, Xiaoqing; Sun, Haoyang; Zhao, Hui; Li, Ying

    2016-08-02

    In this paper, the detailed behaviors of all the molecules, especially the interfacial array behaviors of surfactants and diffusion behaviors of gas molecules, in foam systems with different gases (N2, O2, and CO2) being used as foaming agents were investigated by combining molecular dynamics simulation and experimental approaches for the purpose of interpreting how the molecular behaviors effect the properties of the foam and find out the key factors which fundamentally determine the foam stability. Sodium dodecyl sulfate SDS was used as the foam stabilizer. The foam decay and the drainage process were determined by Foamscan. A texture analyzer (TA) was utilized to measure the stiffness and viscoelasticity of the foam films. The experimental results agreed very well with the simulation results by which how the different gas components affect the interfacial behaviors of surfactant molecules and thereby bring influence on foam properties was described.

  1. Experiments to Populate and Validate a Processing Model for Polyurethane Foam: Additional Data for Structural Foams

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Rekha R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Giron, Nicholas Henry [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Long, Kevin Nicholas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Russick, Edward M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    We are developing computational models to help understand manufacturing processes, final properties and aging of structural foam, polyurethane PMDI. Th e resulting model predictions of density and cure gradients from the manufacturing process will be used as input to foam heat transfer and mechanical models. BKC 44306 PMDI-10 and BKC 44307 PMDI-18 are the most prevalent foams used in structural parts. Experiments needed to parameterize models of the reaction kinetics and the equations of motion during the foam blowing stages were described for BKC 44306 PMDI-10 in the first of this report series (Mondy et al. 2014). BKC 44307 PMDI-18 is a new foam that will be used to make relatively dense structural supports via over packing. It uses a different catalyst than those in the BKC 44306 family of foams; hence, we expect that the reaction kineti cs models must be modified. Here we detail the experiments needed to characteriz e the reaction kinetics of BKC 44307 PMDI-18 and suggest parameters for the model based on these experiments. In additi on, the second part of this report describes data taken to provide input to the preliminary nonlinear visco elastic structural response model developed for BKC 44306 PMDI-10 foam. We show that the standard cu re schedule used by KCP does not fully cure the material, and, upon temperature elevation above 150°C, oxidation or decomposition reactions occur that alter the composition of the foam. These findings suggest that achieving a fully cured foam part with this formulation may be not be possible through therma l curing. As such, visco elastic characterization procedures developed for curing thermosets can provide only approximate material properties, since the state of the material continuously evolves during tests.

  2. Experiments to Populate and Validate a Processing Model for Polyurethane Foam: Additional Data for Structural Foams.

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Rekha R.; Celina, Mathias C.; Giron, Nicholas Henry; Long, Kevin Nicholas; Russick, Edward M.

    2015-01-01

    We are developing computational models to help understand manufacturing processes, final properties and aging of structural foam, polyurethane PMDI. Th e resulting model predictions of density and cure gradients from the manufacturing process will be used as input to foam heat transfer and mechanical models. BKC 44306 PMDI-10 and BKC 44307 PMDI-18 are the most prevalent foams used in structural parts. Experiments needed to parameterize models of the reaction kinetics and the equations of motion during the foam blowing stages were described for BKC 44306 PMDI-10 in the first of this report series (Mondy et al. 2014). BKC 44307 PMDI-18 is a new foam that will be used to make relatively dense structural supports via over packing. It uses a different catalyst than those in the BKC 44306 family of foams; hence, we expect that the reaction kineti cs models must be modified. Here we detail the experiments needed to characteriz e the reaction kinetics of BKC 44307 PMDI-18 and suggest parameters for the model based on these experiments. In additi on, the second part of this report describes data taken to provide input to the preliminary nonlinear visco elastic structural response model developed for BKC 44306 PMDI-10 foam. We show that the standard cu re schedule used by KCP does not fully cure the material, and, upon temperature elevation above 150 o C, oxidation or decomposition reactions occur that alter the composition of the foam. These findings suggest that achieving a fully cured foam part with this formulation may be not be possible through therma l curing. As such, visco elastic characterization procedures developed for curing thermosets can provide only approximate material properties, since the state of the material continuously evolves during tests.

  3. Adjoint-based optimization of a foam EOR process

    NARCIS (Netherlands)

    Namdar Zanganeh, M.; Kraaijevanger, J.F.B.M.; Buurman, H.W.; Jansen, J.D.; Rossen, W.R.

    2012-01-01

    We apply adjoint-based optimization to a Surfactant-Alternating-Gas foam process using a linear foam model introducing gradual changes in gas mobility and a nonlinear foam model giving abrupt changes in gas mobility as function of oil and water saturations and surfactant concentration. For the

  4. Co-doped titanium oxide foam and water disinfection device

    Energy Technology Data Exchange (ETDEWEB)

    Shang, Jian-Ku; Wu, Pinggui; Xie, Rong-Cai

    2016-01-26

    A quaternary oxide foam, comprises an open-cell foam containing (a) a dopant metal, (b) a dopant nonmetal, (c) titanium, and (d) oxygen. The foam has the advantages of a high surface area and a low back pressure during dynamic flow applications. The inactivation of Escherichia coli (E. coli) was demonstrated in a simple photoreactor.

  5. Preparation of PMMA Foam by Supercritical CO2 with Ethanol

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Supercritical CO2 with ethanol as blowing agent foamed poly(methylmethacrylate) (PMMA) fiber at 308.15K and in the pressure range from 12-15MPa. The foam structure was detected using scanning electron microscope. It was found that the concentration of ethanol in the fluid is a major parameter to affect the foam structure.

  6. Foam Fractionation of Lycopene: An Undergraduate Chemistry Experiment

    Science.gov (United States)

    Wang, Yan; Zhang, Mingjie; Hu, Yongliang

    2010-01-01

    A novel experiment for the extraction of lycopene from tomato paste by foam fractionation is described. Foam fractionation is a process for separating and concentrating chemicals by utilizing differences in their surface activities. Extraction of lycopene by foam fractionation is a new method that has not been previously reported in the…

  7. Foam for Enhanced Oil Recovery: Modeling and Analytical Solutions

    NARCIS (Netherlands)

    Ashoori, E.

    2012-01-01

    Foam increases sweep in miscible- and immiscible-gas enhanced oil recovery by decreasing the mobility of gas enormously. This thesis is concerned with the simulations and analytical solutions for foam flow for the purpose of modeling foam EOR in a reservoir. For the ultimate goal of upscaling our mo

  8. Foam for Enhanced Oil Recovery: Modeling and Analytical Solutions

    NARCIS (Netherlands)

    Ashoori, E.

    2012-01-01

    Foam increases sweep in miscible- and immiscible-gas enhanced oil recovery by decreasing the mobility of gas enormously. This thesis is concerned with the simulations and analytical solutions for foam flow for the purpose of modeling foam EOR in a reservoir. For the ultimate goal of upscaling our mo

  9. Developments in the uses of foamed bitumen in road pavements

    NARCIS (Netherlands)

    Jenkins, K.J.; Molenaar, A.A.A.; De Groot, J.L.A.; Van de Ven, M.E.C.

    2000-01-01

    Following the lapse in patent rights on foam-producing nozzles, the use of foamed bitumen for the improvement of road construction materials has become more accessible and as a result, it's use increased considerably in the 1990's. In addition, the applications of foamed bitumen process have diversi

  10. The viscosity window of the silicate glass foam production

    DEFF Research Database (Denmark)

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

    2017-01-01

    in a maximum of foam expansion. The expansion maximum is obtained for different glasses (labware, E-glass, CRT panel, soda-lime-silica) by foaming with CaCO3 at isokom temperature and from literature data. In general, the viscosity window was found to be within 104–106 Pa s when foaming with MnO2 or metal...

  11. Variación microestructural del acero AISI 1045 endurecido por rodadura

    Directory of Open Access Journals (Sweden)

    Esther Fernández-Guilarte

    2010-03-01

    Full Text Available En este trabajo se analiza el comportamiento microestructural del acero AISI 1045, endurecido mediante deformación plástica superficial por rodillo, empleando como variables en el proceso de endurecimiento el número de revoluciones, avance y fuerza del torno 16D20. Se empleó el análisis espectral para determinar la composición química del acero y el Nital como reactivo químico para resaltar la estructura metalográfica después de pulida. Se establecen los parámetros de los regímenes de la deformación plástica superficial por rodillo para evaluar la dureza de los pasadores utilizados en las esteras de los equipos de laboreo minero y se expone una metodología para determinar el tiempo de ejecución del corte de las muestras.

  12. Stress corrosion cracking of AISI 321 stainless steel in acidic chloride solution

    Indian Academy of Sciences (India)

    Yanliang Huang

    2002-02-01

    The stress corrosion cracking (SCC) of AISI 321 stainless steel in acidic chloride solution was studied by slow strain rate (SSR) technique and fracture mechanics method. The fractured surface was characterized by cleavage fracture. In order to clarify the SCC mechanism, the effects of inhibitor KI on SCC behaviour were also included in this paper. A study showed that the inhibition effects of KI on SCC were mainly attributed to the anodic reaction of the corrosion process. The results of strain distribution in front of the crack tip of the fatigue pre-cracked plate specimens in air, in the blank solution (acidic chloride solution without inhibitor KI) and in the solution added with KI measured by speckle interferometry (SPI) support the unified mechanism of SCC and corrosion fatigue cracking (CFC).

  13. Quantifying Cutting and Wearing Behaviors of TiN- and CrNCoated AISI 1070 Steel

    Directory of Open Access Journals (Sweden)

    Ahmet Cakan

    2008-11-01

    Full Text Available Hard coatings such as titanium nitride (TiN and chromium nitride (CrN are widely used in cutting and forming tools against wear and corrosion. In the present study, hard coating films were deposited onto AISI 1070 steels by a cathodic arc evaporation plating (CAVP technique. These samples were subjected to wear in a conventional lathe for investigating the tribological behaviour of coating structure, and prenitrided subsurface composition was characterized using scanning electron microscopy (SEM, line scan analyses and X-ray diffraction (XRD. The wear properties of TiN- and CrNcoated samples were determined using an on-line monitoring system. The results show that TiN-coated samples demonstrate higher wear resistance than CrN-coated samples.

  14. Quantifying Cutting and Wearing Behaviors of TiN- and CrNCoated AISI 1070 Steel.

    Science.gov (United States)

    Cakan, Ahmet; Ozkaner, Vedat; Yildirim, Mustafa M

    2008-11-05

    Hard coatings such as titanium nitride (TiN) and chromium nitride (CrN) are widely used in cutting and forming tools against wear and corrosion. In the present study, hard coating films were deposited onto AISI 1070 steels by a cathodic arc evaporation plating (CAVP) technique. These samples were subjected to wear in a conventional lathe for investigating the tribological behaviour of coating structure, and prenitrided subsurface composition was characterized using scanning electron microscopy (SEM), line scan analyses and X-ray diffraction (XRD). The wear properties of TiN- and CrNcoated samples were determined using an on-line monitoring system. The results show that TiN-coated samples demonstrate higher wear resistance than CrN-coated samples.

  15. Microstructure and Hardness of High Temperature Gas Nitrided AISI 420 Martensitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    Ibrahim Nor Nurulhuda Md.

    2014-07-01

    Full Text Available This study examined the microstructure and hardness of as-received and nitrided AISI 420 martensitic stainless steels. High temperature gas nitriding was employed to treat the steels at 1200°C for one hour and four hours using nitrogen gas, followed by furnace cooled. Chromium nitride and iron nitride were formed and concentrated at the outmost surface area of the steels since this region contained the highest concentration of nitrogen. The grain size enlarged at the interior region of the nitrided steels due to nitriding at temperature above the recrystallization temperature of the steel and followed by slow cooling. The nitrided steels produced higher surface hardness compared to as-received steel due to the presence of nitrogen and the precipitation of nitrides. Harder steel was produced when nitriding at four hours compared to one hour since more nitrogen permeated into the steel.

  16. Effect of plasma nitriding time on surface properties of hard chromium electroplated AISI 1010 steel

    Energy Technology Data Exchange (ETDEWEB)

    Kocabas, Mustafa [Yildiz Technical Univ., Istanbul (Turkey). Metallurgical and Materials Engineering Dept.; Danisman, Murat [Gedik Univ., Istanbul (Turkey). Electrical and Electronic Engineering Dept.; Cansever, Nurhan [Yildiz Technical Univ., Istanbul (Turkey); Uelker, Suekrue [Afyon Kocatepe Univ. (Turkey). Dept. of Mechanical Engineering

    2015-06-01

    Properties of steel can be enhanced by surface treatments such as coating. In some cases, further treatments such as nitriding can also be used in order to get even better results. In order to investigate the properties of nitride layer on hard Cr coated AISI 1010 steel, substrates were electroplated to form hard Cr coatings. Then hard Cr coatings were plasma nitrided at 700 C for 3 h, 5 h and 7 h and nitride phases on the coatings were investigated by X-ray diffraction analysis. The layer thickness and surface properties of nitride films were investigated by scanning electron microscopy. The hardness and adhesion properties of Cr-N phases were examined using nano indentation and Daimler-Benz Rockwell C adhesion tests. The highest measured hardness was 24.1 GPa and all the three samples exhibited poor adhesion.

  17. Diffusion characteristics of plasma nitrided hard chromium on AISI 1010 steel

    Energy Technology Data Exchange (ETDEWEB)

    Danisman, Murat [Gedik Univ., Istanbul (Turkey). Electronic Engineering Dept.; Kocabas, Mustafa; Cansever, Nurhan [Yildiz Technical Univ., Istanbul (Turkey)

    2015-06-01

    In order to investigate the different Cr-N formation characteristics of plasma nitrided hard Cr coatings, Cr was electrodeposited on AISI 1010 steel and plasma nitrided at 600, 700 and 800 C for 3 h, 5 h and 7 h, respectively. Phase analyses of resulting Cr-N phases and grain size of Cr layer before and after nitriding process were calculated by X-ray diffraction analysis. Structure of nitride layer and its thickness were analyzed using scanning electron microscopy micrographs. The micrographs indicated that samples consisted of three distinctive layers. In order to distinguish these layers, scanning electron microscopy and energy dispersive spectroscopy (EDX) analysis were used as well as elemental distribution versus depth was plotted. The Cr-N diffusion was investigated by layer thickness measurements, and diffusion coefficient as well as activation energies were calculated.

  18. Optimization of process parameters of ECM by RSM on AISI 202 steel

    Directory of Open Access Journals (Sweden)

    P. Alex John Britto

    2015-12-01

    Full Text Available The machining of complex shaped designs was difficult earlier, but with the advent of the newer machining processes incorporating in it electrical, chemical & mechanical processes, manufacturing has redefined itself. Especially, the Electrochemical Machining (ECM process is used to machine the hard to cut materials without producing heat and friction. Hence, in this work, the ECM process has been chosen to machine SS AISI 202 steel. This study establishes the effect of process parameters such as voltage, current and concentration of electrolyte on the responses on material removal rate (MRR. In this work, second-order quadratic models were developed for MRR, considering the electrolyte concentration, voltage and current as the machining parameters, using central composite design. The developed models were used for Response Surface Methodology (RSM optimization by desirability function approach to determine the optimum machining parameters.

  19. Martensitic Transformation during Fatigue Testing of an AISI 301LN Stainless Steel

    Science.gov (United States)

    Mateo, A.; Fargas, G.; Zapata, A.

    2012-02-01

    The plastic deformation accumulated during fatigue testing can induce the transformation of austenite to martensite in metastable austenitic stainless steels. To analyze this issue, a metastable austenitic stainless steel grade AISI 301 LN was studied in two different conditions, i.e. annealed and cold rolled. In the first case, the steel was fully austenitic, whereas cold rolled material had almost 30% of martensite. High cycle fatigue tests at a stress ratio of 0.8 were carried out on flat specimens from both steel conditions. Several characterization techniques, including optical microscopy, X-ray diffraction (XRD) and electron back scattered diffraction (EBSD), were used to detect and quantify the martensite induced by the cyclic deformation.

  20. Active flux tungsten inert gas welding of austenitic stainless steel AISI 304

    Directory of Open Access Journals (Sweden)

    D. Klobčar

    2016-10-01

    Full Text Available The paper presents the effects of flux assisted tungsten inert gas (A-TIG welding of 4 (10 mm thick austenitic stainless steel EN X5CrNi1810 (AISI 304 in the butt joint. The sample dimensions were 300 ´ 50 mm, and commercially available active flux QuickTIG was used for testing. In the planned study the influence of welding position and weld groove shape was analysed based on the penetration depth. A comparison of microstructure formation, grain size and ferrit number between TIG welding and A-TIG welding was done. The A-TIG welds were subjected to bending test. A comparative study of TIG and A-TIG welding shows that A-TIG welding increases the weld penetration depth.

  1. Adhesion of composite carbon/hydroxyapatite coatings on AISI 316L medical steel

    Directory of Open Access Journals (Sweden)

    J. Gawroński

    2009-07-01

    Full Text Available In this paper are contains the results of studies concerning the problems associated with increased of hydroxyapatite (HAp adhesion, manufactured by using Pulse Laser Deposition (PLD method, to the austenitic steel (AISI 316L through the coating of carbon interlayer on it. Carbon coating was deposited by Radio Frequency Plasma Assisted Chemical Vapour Deposition (RF PACVD method.Test results unequivocally showed that the intermediate carbon layer in a determined manner increase the adhesion of hydroxyapatite to the metallic substrate. Obtained results give rise to deal with issues of manufacturing composite bilayer – carbon film/HAp – on ready implants, casted from austenitic cast steel by lost-wax process method as well as in gypsum forms.

  2. Analysis of deformation induced martensite in AISI 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Jagarinec, Darko; Kirbis, Peter; Predan, Jozef; Vuherer, Tomaz; Gubeljak, Nenad [Maribor Univ. (Slovenia). Faculty of Mechanical Engineering

    2016-08-01

    Metastable austenite stainless steel AISI 316L is sensitive to cold deformation, where transformation from austenite to martensite occurred. The bending deformation as the formation process leads to tensile and compression throughout the thickness of the billet. Tensile testing of the specimen causes differences in the true stress-strain along the contraction neck prior to fracture as well. The aim of the paper is to find correlation between microhardness as brief inspection parameters and extension of martensitic transformation. The total equivalent plastic strain extend diagram obtained by numerical simulation of bending was compared with tensile true stress-strain diagram. Results show very good correlation between hardness, true strain and martesite content. Therefore, one can conclude that by hardness measurement, it is possible to measure the level of equivalent plastic strain until ultimate tensile stress as a linear correlation between hardness, true strain and martesite content.

  3. An investigation of the aseptic loosening of an AISI 316L stainless steel hip prosthesis.

    Science.gov (United States)

    Godec, Matjaz; Kocijan, Aleksandra; Dolinar, Drago; Mandrino, Djordje; Jenko, Monika; Antolic, Vane

    2010-08-01

    The total replacement of joints by the implantation of permanently indwelling prosthetic components has been one of the major successes of modern surgery in terms of relieving pain and correcting deformity. However, the aseptic loosening of a prosthetic-joint component is the most common reason for joint-revision surgery. Furthermore, it is thought that wear particles are one of the major contributors to the development and perpetuation of aseptic loosening. The aim of the present study was to identify the factors related to the aseptic loosening of an AISI 316L stainless steel total hip prosthesis. The stem was evaluated by x-ray photoelectron spectroscopy, with polished and rough regions being analyzed in order to establish the differences in the chemical compositions of both regions. Specific areas were examined using scanning electron microscopy with energy dispersive x-ray spectroscopy and light microscopy.

  4. Microstructure and Texture Evolutions in AISI 1050 Steel by Flow Forming

    Energy Technology Data Exchange (ETDEWEB)

    Bedekar, Vikram [Timken Technology Center, Canton, OH; Pauskar, Praveen [Ohio State University, Columbus; Shivpuri, Rajiv [Ohio State University, Columbus; Howe, Jane Y [ORNL

    2014-01-01

    Hot rolled and annealed AISI 1050 steel cylindrical coupons were flow formed at different levels of deformation (66% and 90% wall thickness reduction). TEM studies revealed development of ultra fine (sub) grain cell structure due to severe plastic deformation. The transverse subgrain size changed from 10 m (beginning) to 300nm (66% deformation) to 40nm (90% deformation). EBSD study revealed decreased recrystallization fraction at 90% deformation compared with 66% deformation due to orientation pinning from preferred orientation along {002} planes. No evidence of dislocation pinning or cracking was observed on any samples. The aim of the present work is to study the deformation behaviour and microstructural evolution during conventional flow forming process. The study also sheds light on the strengthening behaviour and structural changes during severe straining.

  5. Optimization of Process Parameters in Turning of AISI 8620 Steel Using Taguchi and Grey Taguchi Analysis

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Sharma

    2014-03-01

    Full Text Available The aim of this research is to investigate the optimization of cutting parameters (cutting speed, feed rate and depth of cut for surface roughness and metal removal rate in turning of AISI 8620 steel using coated carbide insert. Experiments have been carried out based on Taguchi L9 standard orthogonal array design with three process parameters namely cutting speed, feed rate and depth of cut for surface roughness and metal removal rate. The objective function has been chosen in relation to surface roughness and metal removal rate for quality target. Optimal parameters contribution of the CNC turning operation was obtained via grey relational analysis. The analysis of variance is applied to identify the most significant factor. Experiment with the optimized parameter setting, which has been obtained from the analysis, are giving to validate the results.

  6. Nitrocarburizing of AISI-304 stainless steel using high-voltage plasma immersion ion implantation

    Science.gov (United States)

    Abd El-Rahman, A. M.; Mohamed, S. H.; Ahmed, M. R.; Richter, E.; Prokert, F.

    2009-05-01

    AISI-304 austenitic stainless steel has been nitrocarburized in N 2 and C 2H 2 ambient using high-voltage plasma immersion ion implantation (PIII) technology. The use of different PIII treatment times revealed important hints with respect to the microstructural, mechanical and corrosion properties of the nitrocarburized layer. Grazing incidence X-ray diffraction (GIXRD) shows the presence of nitride ( γN and CrN) and carbide ( γC and Fe 3C) phases. Glow discharge optical spectroscopy (GDOS) has been used to characterize the elemental depth profiles in which the thickness of the modified layers is derived. Dynamic microindentation method is used for the study of mechanical performance of the nitrocarburized layer as well as the untreated material. The microhardness has been increased to a maximum value of more than nine times compared to that of the untreated one. The corrosion performance is characterized by potentiodynamic polarization technique and was found to be treatment time dependent.

  7. Surface characteristics analysis of dry EDMed AISI D2 steel using modified tool design

    Energy Technology Data Exchange (ETDEWEB)

    Pragadish, N.; Kumar, M. Pradeep [Anna University, Chennai (China)

    2015-04-15

    A modified tool design is proposed which helps in drilling holes without any central core, and also enables the effective removal of the debris particles. Experiments were conducted on AISI D2 Steel using copper electrode as tool in both conventional EDM and dry EDM processes and the performance of both processes is compared. Experiments were designed using Taguchi's L27 orthogonal array. Discharge current (I), gap voltage (V), pulse on time (T{sub ON}), gas pressure (P) and tool rotational speed (N) were chosen as the various input parameters, and their effect on the material removal rate (MRR), surface roughness (SR), surface morphology, microstructure and elemental composition of the machined surface is analyzed. The experimental results show better surface characteristics in the surface machined under dry EDM process.

  8. ANALYSIS OF CUTTING FORCE AND CHIP MORPHOLOGY DURING HARD TURNING OF AISI D2 STEEL

    Directory of Open Access Journals (Sweden)

    X. M. ANTHONY

    2015-03-01

    Full Text Available In this research work AISI D2 tool steel at a hardness of 55 HRC is being used for experimental investigation. Cutting speed, feed rate and depth of cut are the cutting parameters considered for the experimentation along with tool geometry namely, nose radius, clearance angle and rake angle. Three different cutting tool materials are used for experimentation namely multicoated carbide, cermet and ceramic inserts. The cutting force generated during the machining process is being measured using Kistler dynamometer and recorded for further evaluation. The chips produced during the machining process for every experimental trail is also collected for understanding the chip morphology. Based on the experimental data collected Analysis of Variance (ANOVA was conducted to understand the influence of all cutting parameters and tool geometry on cutting force.

  9. Tensile and Impact Properties of Shielded Metal Arc Welded AISI 409M Ferritic Stainless Steel Joints

    Institute of Scientific and Technical Information of China (English)

    K.Shanmugam; A.K.Lakshminarayanan; V.Balasubramanian

    2009-01-01

    The present study is concerned with the effect of filler metals such as austenitic stainless steel, ferritic stainless steel and duplex stainless steel on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure and fracture surface morphology of the joints fabricated by austenitic stainless steel, ferritic stainless steel and duplex stainless steel filler metals were evaluated and the results were reported. From this investigation, it is found that the joints fabricated by duplex stainless steel filler metal showed higher tensile strength and hardness compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Joints fabricated by austenitic stainless steel filler metal exhibited higher ductility and impact toughness compared with the joints fabricated by ferritic stainless steel and duplex stainless steel filler metals.

  10. 3DII implantation effect on corrosion properties of the AISI/SAE 1020 steel

    Energy Technology Data Exchange (ETDEWEB)

    Dulce M., H.J.; Rueda V., Alejandro [Universidad Francisco de Paula Santander, A.A. 1055, Cucuta (Colombia); Dougar-Jabon, Valeri [Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia)

    2005-08-01

    The three dimensional ion implantation technology (3DII) is one of the methods of improving the tribological characteristics and resistance to hydrogen embrittlement processes in metals. In this report, some results concerning the resistance effect of nitrogen ion implantation to oxidation of the sample, made of AISI/SAE 1020 steel, are given. The nitrogen ions were implanted in the discharge chamber of the JUPITER reactor. Both the treated and untreated samples were tested through potential-static measurements, which permitted to determine the corrosion current, the slopes that characterise the braking level of anode and cathode reactions. The polarization resistance near the corrosion potential is calculated. The results of the study encourage to consider the nitrogen ion implantation in high voltage and low pressure discharges as one of the methods of anticorrosive protection which do not change the geometric configuration of the treated steel pieces. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Surface Modification by Nitrogen Plasma Immersion Ion Implantation on Austenitic AISI 304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    Miguel CASTRO-COLIN; William DURRER; Jorge ALPEZ; Enrique RAMIREZ-HOMS

    2016-01-01

    Surfaces of AISI 304 austenitic stainless steel plates nitrided by plasma immersion ion implantation (PIII) technology were studied by means of Auger electron spectroscopy (AES)and X-ray photoelectron spectroscopy (XPS)to determine the effect of the nitriding process on the surface and subjacent layers.Elemental compositions obtained by AES and XPS at varying depths indicate that the saturation of N is relatively constant as a function of depth,indicating the reliability of PIII technology for subsurface saturation.It is concluded that the concentrations of both Cr and O increase with depth,the subjacent oxide is driven by the Ar+ sputtering process used to access the lower layers,and then N is bound to Cr.

  12. The Investigation of Surface Roughness on AISI 1040 Steel with Dry Turning

    Directory of Open Access Journals (Sweden)

    Nergizhan Kavak

    2012-12-01

    Full Text Available In this study, the effect of cutting speed and feed rate on the surface roughness was investigated experimentaly in the machining of AISI 1040 steel being mostly used in industry. Experiments was done by dry turning with uncoated cementite carbite cutting tools at different speeds (46. 91 ve 128 m/dk and feed rates (0.16, 0.22 ve 0.28 mm/dev while cutting depth stays stable at 2 mm. It was observed that workpiece surface quality get worse with the increase of feed rate or decrease of cutting speed. As a result of this work, it was seen that 128 m/min cutting speed and 0.16 mm/rev feed rate for the 2 mm cutting depth are the optimum cutting conditions from the point of surface quality.

  13. Effect of the powder particle size on the wear behavior of boronized AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Guenen, Ali [Mustafa Kemal Univ., Hatay (Turkey). Dept. of Metallurgy and Material Engineering; Kuecuek, Yilmaz; Oege, Mecit; Goek, M. Sabri [Bartin Univ. (Turkey). Dept. of Mechanical Engineering; Er, Yusuf [Firat Univ., Elazig (Turkey); Cay, V. Veli [Dicle Univ., Diyarbakir (Turkey). Civil Aviation Higher School

    2015-06-01

    In this study, the AISI 304 steel specimens were boronized with nanoboron of the size of 10 50 nm and commercial Ekabor 3 powders (<1400 μm) at 950 C to 1000 C for 2 h and 4 h. Boronized steel specimens were characterized via SEM, microhardness and XRD analyses. Abrasive wear behavior of the specimens, boronized at different temperatures and treatment durations, were examined. The fixed ball micro-abrasion tests were carried out using the abrasive slurry, prepared with different SiC powder particle sizes on the boronized specimens at different rotational speeds. The specimens boronized with nanoboron powders exhibited a higher hardness and abrasive wear resistance than the samples boronized with the Ekabor 3 powders.

  14. Evaluation of the corrosion resistance of AISI 316 stainless steel filters

    Directory of Open Access Journals (Sweden)

    Luzinete Pereira Barbosa

    2005-06-01

    Full Text Available In this investigation, the corrosion resistance of AISI 316 SS filters prepared with powders in the size ranges 74-44 µm and 210-105 µm and compacted with pressures of 300 MPa and 400 MPa has been evaluated in naturally aerated 0.5 M H2SO4 solution at 25 °C. Weight loss of filters manufactured with compacting pressure of 400 MPa were significantly higher than that of filters compacted at 300 MPa. The filter compacted at 400 MPa had higher carbon and nitrogen contents compared to those compacted at 300 MPa. The former also had chromium rich precipitates and oxides in the grain boundaries. The pores in filters compacted at 400 MPa were smaller than in filters compacted at 300 MPa. Smaller pores favor the formation of concentration cells and consequently, increased crevice corrosion.

  15. Effect of adhesive geometry on the tensile properties of AISI 1350 steel

    Directory of Open Access Journals (Sweden)

    A. Yasar

    2011-01-01

    Full Text Available It is utilized increasingly to use adhesive bonding in automotive industry to join structural components of metallic materials. The aim of this experimental study is to extend the information available to the automotive design engineer and contribute the better understanding of how the various geometrical shaped of steel parts affect the adhesive bonding. In this study, different types of lap joints, such as butt, step butt, scarf, tubular lap, were used to determine the mechanical strength of SAE/AISI 1350 steel. It has been observed that the cylindrical geometries can be subject to more stress compared to square specimens generally and the geometries with both tensile and shear stress can stand more stress per unit compared with the specimens with only tensile stress.

  16. Effect of Hydrogen and Strain-Induced Martensite on Mechanical Properties of AISI 304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    Sang Hwan Bak

    2016-07-01

    Full Text Available Plastic deformation and strain-induced martensite (SIM, α′ transformation in metastable austenitic AISI 304 stainless steel were investigated through room temperature tensile tests at strain rates ranging from 2 × 10−6 to 2 × 10−2/s. The amount of SIM was measured on the fractured tensile specimens using a feritscope and magnetic force microscope. Elongation to fracture, tensile strength, hardness, and the amount of SIM increased with decreasing the strain rate. The strain-rate dependence of RT tensile properties was observed to be related to the amount of SIM. Specifically, SIM formed during tensile tests was beneficial in increasing the elongation to fracture, hardness, and tensile strength. Hydrogen suppressed the SIM formation, leading to hydrogen softening and localized brittle fracture.

  17. Effect of Carbon and Nitrogen Content on Deformation and Fracture of AISI 304 Austenitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    C. Menapace

    2008-04-01

    Full Text Available The effect of small differences in the content of carbon and nitrogen on the room temperature tensile deformation and fracture behaviour of an AISI 304 stainless steel was studied. In the steel containing the lower amount of carbon and nitrogen, a higher amount of strain induced alfa’ martensite is formed, which increases strain hardening rate and both uniform and total elongation at fracture. The presence of large martensitic areas in the cross section causes strain localization at the austenite/martensite interface, which promotes the nucleation of cracks and their propagation along the interface. This results in a decrease of Ultimate Tensile Strength. Strain induced transformation slightly reduces strain rate sensitivity, as well.

  18. Effect of Plasma Nitriding Temperatures on Characteristics of Aisi 201 Austenitic Stainless Steel

    Science.gov (United States)

    Gao, Yuxin; Zheng, Shaomei

    2016-10-01

    Samples of AISI 201 austenitic stainless steel were produced by plasma nitriding at 350∘C, 390∘C, 420∘C, 450∘C and 480∘C for 5h. Systematic characterization of the nitrided layer was carried out in terms of micrograph observations, phase identification, chemical composition depth profiling, surface microhardness measurements and electrochemical corrosion tests. The results show that the surface hardness and the layer thickness increased with increasing temperature. XRD indicated that a single S-phase layer was formed during low temperature (≤420∘C), while Cr2N or CrN phase was formed besides S-phase when nitrided at 450∘C and 480∘C. The specimen treated at 390∘C presents a much enhanced corrosion resistance compared to the untreated substrate. The corrosion resistance deteriorated for samples treated above 450∘C due to the formation of chromium nitrides.

  19. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.

    2005-01-01

    Unlike in autogenous laser welding, hybrid laser welding of stainless steel could introduce grain boundary carbides due to low cooling rates. Formation of grain boundary carbides leads to reduced corrosion properties. Studies have initially been carried out on hybrid laser welding and subsequent...... laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  20. Fatigue assessment by energy approach during tensile tests on AISI 304 steel

    Directory of Open Access Journals (Sweden)

    A. Risitano

    2017-01-01

    Full Text Available Estimation of the fatigue limit for steel ductile materials using non-destructive methods is a topic of great interest to researchers today. In recent years, the method adopted has implemented infrared sensors to detect the surface temperature and correlate it with the fatigue limit. In previous paper, a new energy approach was proposed to investigate the fatigue limit during tensile test. The numerical procedure proposed by Chrysochoos is adopted to clean infrared images and applied to analyse the surface heat sources during tensile test. AISI 304 specimens with rectangular cross-sections are tested. Moreover fatigue tests at increasing loads were carried out on steel by a stepwise succession, applied to the same specimen, for applying the thermographic method. The predictions of the fatigue limit, obtained by the analysis of the energy evolution during the static tests, were compared with the predictions obtained applying the thermographic method during fatigue tests.

  1. Determining Ms temperature on a AISI D2 cold work tool steel using magnetic Barkhausen noise

    Energy Technology Data Exchange (ETDEWEB)

    Huallpa, Edgar Apaza, E-mail: gared1@gmail.com [Escola Politécnica da Universidade de São Paulo, Av. Prof. Mello Moraes 2463, 05508-030 SP (Brazil); Sánchez, J. Capó, E-mail: jcapo@usp.br [Departamento de Física, Facultad de Ciencias Naturales, Universidad de Oriente, Av. Patricio Lumumba s/n 90500, Santiago de Cuba (Cuba); Padovese, L.R., E-mail: lrpadove@usp.br [Escola Politécnica da Universidade de São Paulo, Av. Prof. Mello Moraes 2463, 05508-030 SP (Brazil); Goldenstein, Hélio, E-mail: hgoldens@usp.br [Escola Politécnica da Universidade de São Paulo, Av. Prof. Mello Moraes 2463, 05508-030 SP (Brazil)

    2013-11-15

    Highlights: ► MBN was used to follow the martensite transformation in a tool steel. ► The results were compared with resistivity experiments. ► The Ms was estimated with Andrews equation coupled to ThermoCalc calculations. The experimental results showed good agreement. -- Abstract: The use of Magnetic Barkhausen Noise (MBN) as a experimental method for measuring the martensite start (Ms) temperature was explored, using as model system a cold-work tool steel (AISI D2) austenitized at a very high temperature (1473 K), so as to transform in sub-zero temperatures. The progress of the transformation was also followed with electrical resistance measurements, optical microscopy and scanning electron microscopy. Both MBN and resistivity measurements showed a change near 230 K during cooling, corresponding to the Ms temperature, as compared with 245 K, estimated with Andrews empirical equation applied to the austenite composition calculated using ThermoCalc.

  2. Dynamic fracture toughness and Charpy impact properties of an AISI 403 martensitic stainless steel

    Science.gov (United States)

    Sreenivasan, P. R.; Ray, S. K.; Mannan, S. L.; Rodriguez, P.

    1996-04-01

    Dynamic fracture toughness and Charpy impact properties of a normalised and tempered AISI 403 martensitic stainless steel obtained from instrumented impact tests are presented. Procedures for estimating dynamic fracture toughness ( KId) from the load-time traces obtained in instrumented tests of unprecracked Charpy V-notch (CVN) specimens are considered. The estimated KId values show reasonable agreement with those obtained from instrumented drop-weight and precracked Charpy tests. Also, except in the upper transition and uppershelf regions, the ASME KIR curve is generally conservative (i.e. gives lower KId values) when compared to the above KId estimates. The conservatism of the ASME KIR at the upper transition and uppershelf temperatures needs verification/validation. The lowest KId values estimated at the lower shelf temperatures for the above steel, namely, 33-42 MPa√m are in good agreement with the reported values of 35-50 MPa√m for the same steel in the literature.

  3. Influence of nitrogen alloying on hydrogen embrittlement in AISI 304-type stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Hannula, S.-P.; Hanninen, H.; Tahtinen, S.

    1984-12-01

    Hydrogen embrittlement of AISI 304-type austenitic stainless steels has been studied with special emphasis on the effects of the nitrogen content of the steels. Hydrogen charging was found to degrade the mechanical properties of all the steels studied, as measured by a tensile test. The fracture surfaces of hydrogen charged specimens were brittle cleavage-like whereas the uncharged specimens showed ductile, dimpled fracture. In sensitized materials transgranular cleavage mode of fracture was replaced by an intergranular mode of fracture and the losses of mechanical properties were higher. Nitrogen alloying decreased the hydrogen-induced losses of mechanical properties by increasing the stabilit of austenite. In sensitized steels the stability of austenite and nitrogen content were found to have only a minor effect on hydrogen embrittlement, except when sensitization had caused ..cap alpha..'-martensite transformation at the grain boundaries.

  4. Influence of nitrogen alloying on hydrogen embrittlement in AISI 304-type stainless steels

    Science.gov (United States)

    Hannula, Simo-Pekka; Hänninen, Hannu; Tähtinen, Seppo

    1984-12-01

    Hydrogen embrittlement of AISI 304-type austenitic stainless steels has been studied with special emphasis on the effects of the nitrogen content of the steels. Hydrogen charging was found to degrade the mechanical properties of all the steels studied, as measured by a tensile test. The fracture surfaces of hydrogen charged specimens were brittle cleavage-like whereas the uncharged specimens showed ductile, dimpled fracture. In sensitized materials transgranular cleavage mode of fracture was replaced by an intergranular mode of fracture and the losses of mechanical properties were higher. Nitrogen alloying decreased the hydrogen-induced losses of mechanical properties by increasing the stability of austenite. In sensitized steels the stability of austenite and nitrogen content were found to have only a minor effect on hydrogen embrittlement, except when sensitization had caused α'-martensite transformation at the grain boundaries.

  5. Influence of Laser Peening on Phase Transformation and Corrosion Resistance of AISI 321 steel

    Science.gov (United States)

    Karthik, D.; Swaroop, S.

    2016-07-01

    The objective of this study is to investigate the influence of laser peening without coating (LPwC) on austenitic to martensitic (γ → α') phase transformation and corrosion behavior of austenitic stainless steel AISI 321 in 3.5% NaCl environment. Results indicate that LPwC induces a large compressive residual stresses of nearly -854 MPa and γ → α' phase transformation of about 18% (volume fraction). Microstructures of peened surface confirmed the γ → α' phase transformation and showed no grain refinement. Hardness increased slightly with a case depth of 900 μm. Despite the smaller surface roughness introduced, corrosion resistance improved after peening due to compressive residual stresses.

  6. Acoustic Emission Methodology to Evaluate the Fracture Toughness in Heat Treated AISI D2 Tool Steel

    Science.gov (United States)

    Mostafavi, Sajad; Fotouhi, Mohamad; Motasemi, Abed; Ahmadi, Mehdi; Sindi, Cevat Teymuri

    2012-10-01

    In this article, fracture toughness behavior of tool steel was investigated using Acoustic Emission (AE) monitoring. Fracture toughness ( K IC) values of a specific tool steel was determined by applying various approaches based on conventional AE parameters, such as Acoustic Emission Cumulative Count (AECC), Acoustic Emission Energy Rate (AEER), and the combination of mechanical characteristics and AE information called sentry function. The critical fracture toughness values during crack propagation were achieved by means of relationship between the integral of the sentry function and cumulative fracture toughness (KICUM). Specimens were selected from AISI D2 cold-work tool steel and were heat treated at four different tempering conditions (300, 450, 525, and 575 °C). The results achieved through AE approaches were then compared with a methodology proposed by compact specimen testing according to ASTM standard E399. It was concluded that AE information was an efficient method to investigate fracture characteristics.

  7. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.

    2005-01-01

    Unlike in autogenous laser welding, hybrid laser welding of stainless steel could introduce grain boundary carbides due to low cooling rates. Formation of grain boundary carbides leads to reduced corrosion properties. Studies have initially been carried out on hybrid laser welding and subsequent...... laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  8. Electrochemical behaviour of iron and AISI 304 stainless steel in simulated acid rain solution

    Energy Technology Data Exchange (ETDEWEB)

    Pilic, Zora; Martinovic, Ivana [Mostar Univ. (Bosnia and Herzegovina). Dept. of Chemistry

    2016-10-15

    The growth mechanism and properties of the oxide films on iron and AISI 304 stainless steel were studied in simulated acid rain (pH 4.5) by means of electrochemical techniques and atomic absorption spectrometry. The layer-pore resistance model was applied to explain a potentiodynamic formation of surface oxides. It was found that the growth of the oxide film on iron takes place by the low-field migration mechanism, while that on the stainless steel takes place by the high-field mechanism. Kinetic parameters were determined. Impedance measurements revealed that Fe surface film has no protective properties at the open circuit potential, while the resistance of stainless steel oxide film is very high. The concentration of the metallic ions released into solution and measured by atomic absorption spectroscopy was in accordance with the results obtained from the electrochemical techniques.

  9. Corrosion behavior of low energy, high temperature nitrogen ion-implanted AISI 304 stainless steel

    Indian Academy of Sciences (India)

    M Ghorannevis; A Shokouhy; M M Larijani; S H Haji Hosseini; M Yari; A Anvari; M Gholipur Shahraki; A H Sari; M R Hantehzadeh

    2007-01-01

    This work presents the results of a low-energy nitrogen ion implantation of AISI 304 type stainless steel (SS) at a moderate temperature of about 500° C. The nitrogen ions are extracted from a Kauffman-type ion source at an energy of 30 keV, and ion current density of 100 A cm-2. Nitrogen ion concentration of 6 × 1017, 8 × 1017 and 1018 ions cm-2, were selected for our study. The X-ray diffraction results show the formation of CrN polycrystalline phase after nitrogen bombardment and a change of crystallinity due to the change in nitrogen ion concentration. The secondary ion mass spectrometry (SIMS) results show the formation of CrN phases too. Corrosion test has shown that corrosion resistance is enhanced by increasing nitrogen ion concentration.

  10. Domain growth kinetics in stratifying foam films

    Science.gov (United States)

    Zhang, Yiran; Sharma, Vivek

    2015-11-01

    Baking bread, brewing cappuccino, pouring beer, washing dishes, shaving, shampooing, whipping eggs and blowing bubbles all involve creation of aqueous foam films. Typical foam films consist of two surfactant-laden surfaces that are ~ 5 nm - 10 micron apart. Sandwiched between these interfacial layers is a fluid that drains primarily under the influence of viscous and interfacial forces, including disjoining pressure. Interestingly, a layered ordering of micelles inside the foam films (thickness growth regimes with characteristic scaling laws. Though several studies have focused on the expansion dynamics of isolated domains that exhibit a diffusion-like scaling, the change in expansion kinetics observed after domains contact with the Plateau border has not been reported and analyzed before.

  11. Aqueous foams stabilised solely by nanoparticles

    Science.gov (United States)

    Langevin, Dominique

    2011-03-01

    Particles are being increasingly used to stabilise foams and emulsions, the corresponding emulsions being known as ``Pickering'' emulsions. One of the peculiarities of these systems is the absence of Ostwald ripening: since the bubbles or drops do not grow (coalescence seems also suppressed) both foams and emulsions are stable over extremely long periods of time (months). These features make particles very interesting surface active agents as compared to standard surfactants or polymers/proteins. The origin of the suppression of ripening can be traced to the unusual behaviour of the interfacial layers made by these particles. The layers are solid-like and the usual characterisation methods (surface tension, surface rheology) are not straightforward to use. In this presentation, we will illustrate these difficulties with experiments made with partially hydrophobic silica nanoparticles. We will also discuss the relevance of foam characterisations methods such as multiple light scattering and X-ray tomography.

  12. Insulating Foams Save Money, Increase Safety

    Science.gov (United States)

    2009-01-01

    Scientists at Langley Research Center created polyimide foam insulation for reusable cryogenic propellant tanks on the space shuttle. Meanwhile, a small Hialeah, Florida-based business, PolyuMAC Inc., was looking for advanced foams to use in the customized manufacturing of acoustical and thermal insulation. The company contacted NASA, licensed the material, and then the original inventors worked with the company's engineers to make a new material that was better for both parties. The new version, a high performance, flame retardant, flexible polyimide foam, is used for insulating NASA cryogenic propellant tanks and shows promise for use on watercraft, aircraft, spacecraft, electronics and electrical products, automobiles and automotive products, recreation equipment, and building and construction materials.

  13. Replacements For Ozone-Depleting Foaming Agents

    Science.gov (United States)

    Blevins, Elana; Sharpe, Jon B.

    1995-01-01

    Fluorinated ethers used in place of chlorofluorocarbons and hydrochlorofluorocarbons. Replacement necessary because CFC's and HCFC's found to contribute to depletion of ozone from upper atmosphere, and manufacture and use of them by law phased out in near future. Two fluorinated ethers do not have ozone-depletion potential and used in existing foam-producing equipment, designed to handle liquid blowing agents soluble in chemical ingredients that mixed to make foam. Any polyurethane-based foams and several cellular plastics blown with these fluorinated ethers used in processes as diverse as small batch pours, large sprays, or double-band lamination to make insulation for private homes, commercial buildings, shipping containers, and storage tanks. Fluorinated ethers proved useful as replacements for CFC refrigerants and solvents.

  14. Velocity Field in a Vertical Foam Film

    Science.gov (United States)

    Seiwert, Jacopo; Kervil, Ronan; Nou, Soniraks; Cantat, Isabelle

    2017-01-01

    The drainage of vertical foam films governs their lifetime. For a foam film supported on a rectangular solid frame, when the interface presents a low resistance to shear, the drainage dynamics involves a complex flow pattern at the film scale, leading to a drainage time proportional to the frame width. Using an original velocimetry technique, based on fluorescent foam films and photobleaching, we measure the horizontal and vertical components of the velocity in a draining film, thus providing the first quantitative experimental evidence of this flow pattern. Upward velocities up to 10 cm /s are measured close to the lateral menisci, whereas a slower velocity field is obtained in the center of the film, with comparable downwards and horizontal components. Scaling laws are proposed for all characteristic velocities, coupling gravitational effects, and capillary suction.

  15. Plasmonic nanoshell synthesis in microfluidic composite foams.

    Science.gov (United States)

    Duraiswamy, Suhanya; Khan, Saif A

    2010-09-01

    The availability of robust, scalable, and automated nanoparticle manufacturing processes is crucial for the viability of emerging nanotechnologies. Metallic nanoparticles of diverse shape and composition are commonly manufactured by solution-phase colloidal chemistry methods, where rapid reaction kinetics and physical processes such as mixing are inextricably coupled, and scale-up often poses insurmountable problems. Here we present the first continuous flow process to synthesize thin gold "nanoshells" and "nanoislands" on colloidal silica surfaces, which are nanoparticle motifs of considerable interest in plasmonics-based applications. We assemble an ordered, flowing composite foam lattice in a simple microfluidic device, where the lattice cells are alternately aqueous drops containing reagents for nanoparticle synthesis or gas bubbles. Microfluidic foam generation enables precisely controlled reagent dispensing and mixing, and the ordered foam structure facilitates compartmentalized nanoparticle growth. This is a general method for aqueous colloidal synthesis, enabling continuous, inherently digital, scalable, and automated production processes for plasmonic nanomaterials.

  16. Plastic Foam Withstands Greater Temperatures And Pressures

    Science.gov (United States)

    Cranston, John A.; Macarthur, Doug

    1993-01-01

    Improved plastic foam suitable for use in foam-core laminated composite parts and in tooling for making fiber/matrix-composite parts. Stronger at high temperatures, more thermally and dimensionally stable, machinable, resistant to chemical degradation, and less expensive. Compatible with variety of matrix resins. Made of polyisocyanurate blown with carbon dioxide and has density of 12 to 15 pounds per cubic feet. Does not contibute to depletion of ozone from atmosphere. Improved foam used in cores of composite panels in such diverse products as aircraft, automobiles, railroad cars, boats, and sporting equipment like surfboards, skis, and skateboards. Also used in thermally stable flotation devices in submersible vehicles. Machined into mandrels upon which filaments wound to make shells.

  17. Prediction of acoustic foam properties by numerical simulation of polyurethane foaming process

    Directory of Open Access Journals (Sweden)

    Abdessalam Hichem

    2016-01-01

    Full Text Available This work aims to model and to simulate the polyurethane foaming process. Models taking into account the two main chemical reactions of the formation of polyurethane, the exothermic effect of these reactions as well as the thermo-rheo-kinetic coupling characterizing this process are proposed and implemented in the software NOGRID-points based on a meshless method (Finite Pointset Method. A prediction of some acoustic foam characteristics is also proposed based on the results of the numerical simulation of the foaming process and semi-phenomenological models.

  18. Effect of Heating Rate on Glass Foaming: Transition to Bulk Foam

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, Pavel R.

    2009-02-15

    Foaming of glass is an undesirable side effect of glass fining. According to a recent experimental study, the gas-phase volume in the melt heated at a constant rate dramatically increased with an increased rate of heating. This observation indicates that an increased rate of heating (a natural consequence of the increased processing rate experienced as a result of transition to oxy-fuel firing) may exert a substantial influence on glass foaming in advanced glass-melting furnaces. This paper attributes this effect to the change of mode of foam formation in response to an increased rate of heating.

  19. Acute effects of self-myofascial release using a foam roller on arterial function.

    Science.gov (United States)

    Okamoto, Takanobu; Masuhara, Mitsuhiko; Ikuta, Komei

    2014-01-01

    Flexibility is associated with arterial distensibility. Many individuals involved in sport, exercise, and/or fitness perform self-myofascial release (SMR) using a foam roller, which restores muscles, tendons, ligaments, fascia, and/or soft-tissue extensibility. However, the effect of SMR on arterial stiffness and vascular endothelial function using a foam roller is unknown. This study investigates the acute effect of SMR using a foam roller on arterial stiffness and vascular endothelial function. Ten healthy young adults performed SMR and control (CON) trials on separate days in a randomized controlled crossover fashion. Brachial-ankle pulse wave velocity (baPWV), blood pressure, heart rate, and plasma nitric oxide (NO) concentration were measured before and 30 minutes after both SMR and CON trials. The participants performed SMR of the adductor, hamstrings, quadriceps, iliotibial band, and trapezius. Pressure was self-adjusted during myofascial release by applying body weight to the roller and using the hands and feet to offset weight as required. The roller was placed under the target tissue area, and the body was moved back and forth across the roller. In the CON trial, SMR was not performed. The baPWV significantly decreased (from 1,202 ± 105 to 1,074 ± 110 cm·s-1) and the plasma NO concentration significantly increased (from 20.4 ± 6.9 to 34.4 ± 17.2 μmol·L-1) after SMR using a foam roller (both p < 0.05), but neither significantly differed after CON trials. These results indicate that SMR using a foam roller reduces arterial stiffness and improves vascular endothelial function.

  20. On The Enhancement of Wear Resistance of Hardened Carbon Tool Steel (AISI 1095) With Cryogenic Quenching

    Institute of Scientific and Technical Information of China (English)

    V.Soundararajan; N.Alagurmurthi; K.Palaniradja

    2004-01-01

    Many experimental investigations reveal that it is very difficult to have a completely martensitic structure by any hardening process. Some amount of austenite is generally present in the hardened steel. This austenite existing along with martensite is normally referred as the retained austenite. The presence of retained austenite greatly reduces the mechanical properties and such steels do not develop maximum hardness even after cooling at rates higher than the critical cooling rates.Strength can be improved in hardened steels containing retained austenite by a process known as cryogenic quenching.Untransformed austenite is converted into martensite by this treatment. This conversion of retained austenite into martensite results in increased hardness, wear resistance and dimensional stability of steel. Wear can be defined as the progressive loss of materials from the operating surface of a body occurring as a result of relative motion at the surface. Hardness, load,speed, surface roughness, temperature are the major factors which influences wear. Many studies on wear indicate that increasing hardness decreases the wear of a material. With this in mind, to study the surface wear on a surface modified(Cryogenic treated) steel material an attempt has been made in this paper. In this study as a Part -I Hardening was carried out on carbon tool steel (AISI 1095) of different L/D ratio with conventional quenchants like purified water, aqueous solution and Hot mineral oil. As a Part -Ⅱ hardening was followed by quenching was carried out as said in Part- I and the hardened specimen were quenched in liquid Nitrogen which is at sub zero condition. The specimens were tested for its microstructure, hardness and wear loss. The results were compared and analyzed. The alloying elements increases the content of retained austenite hence the material used was AISI1095 (Carbon 0.9%, Si 0.2%, Mn0.4% and the rest Iron)