WorldWideScience

Sample records for plastic foam covering

  1. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Buoyant apparatus with plastic foam buoyancy. 160.010-5... Vessels § 160.010-5 Buoyant apparatus with plastic foam buoyancy. (a) Buoyant apparatus with plastic foam buoyancy must have a plastic foam body with an external protective covering. The body may be reinforced...

  2. 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.

  3. 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.

  4. 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.

  5. A review of biodegradation of synthetic plastic and foams.

    Science.gov (United States)

    Gautam, R; Bassi, A S; Yanful, E K

    2007-04-01

    Synthetic polymeric foams have pervaded every aspect of modern life. Although foams provide numerous benefits, they also cause a significant environmental litter problem because of their recalcitrant and xenobiotic nature. Biodegradation may provide solution to the problem, but not enough is known about the biodegradation process of synthetic plastic and plasticbased foams. This review has been written to provide an overview of the current state of plastic foam biodegradation. Several biodegradation pathways of a few select synthetic polymers are also presented along with a discussion on some of the physico-chemical factors that can influence the biodegradation of plastic foams.

  6. High strain rate loading of polymeric foams and solid plastics

    Science.gov (United States)

    Dick, Richard D.; Chang, Peter C.; Fourney, William L.

    2000-04-01

    The split-Hopkinson pressure bar (SHPB) provided a technique to determine the high strain rate response for low density foams and solid ABS and polypropylene plastics. These materials are used in the interior safety panels of automobiles and crash test dummies. Because the foams have a very low impedance, polycarbonate bars were used to acquire the strain rate data in the 100 to 1600 l/s range. An aluminum SPHB setup was used to obtain the solid plastics data which covered strain rates of 1000 to 4000 l/s. The curves for peak strain rate versus peak stress for the foams over the test range studied indicates only a slight strain rate dependence. Peak strain rate versus peak stress curves for polypropylene shows a strain rate dependence up to about 1500 l/s. At that rate the solid poly propylene indicates no strain rate dependence. The ABS plastics are strain rate dependent up to 3500 l/s and then are independent at larger strain rates.

  7. VISCO-ELASTIC (PLASTIC) EFFECTS AND FAILURE BEHAVIOR OF PUR FOAMED PLASTICS

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The viscous effects and failure behavior of PUR foamed plastics are investigated by the cycling loading and preloading experiments. On the basis of static and dynamic compressive experiments, the SEM analysis is given for the PUR foamed plastics specimens which have been tested and the deformation as well as failure mechanisms are determined at the same time. In addition, the relaxation characteristics and the failure criterion of foamed plastics are discussed adequately.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-01

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

  9. Polyurethane foam-covered breast implants: a justified choice?

    Science.gov (United States)

    Scarpa, C; Borso, G F; Vindigni, V; Bassetto, F

    2015-01-01

    Even if the safety of the polyurethane prosthesis has been the subject of many studies and professional and public controversies. Nowadays, polyurethane covered implants are very popular in plastic surgery for the treatment of capsular contracture. We have identified 41 papers (1 is a communication of the FDA) by using search browsers such as Pubmed, Medline, and eMedicine. Eleven manuscripts have been used for an introduction, and the remaining thirty have been subdivided into three tables whose results have been summarized in three main chapters: (1) capsular formation and contracture, (2) complications, (3) biodegradation and cancer risk. (1) The polyurethanic capsule is a well defined foreign body reaction characterized by synovial metaplasia, a thin layer of disarranged collagen fibers and a high vascularization. These features make possible a "young" capsule and a low occurrence of capsular contracture even over a long period (10 years); (2) the polyurethane implants may be difficult to remove but there is no evidence that they cause an increase in the other complications; (3) there is no evidence of polyurethane related cancer in long-term studies (after 5 years). Polyurethane foam covered breast implants remain a valid choice for the treatment of capsular contracture even if it would be very useful to verify the ease of removal of the prosthesis and to continue investigations on biodegradation products.

  10. WATER-BLOWN POLYURETHANE RIGID FOAMS MODIFIED BY CHEMICAL PLASTICATION

    Institute of Scientific and Technical Information of China (English)

    YU Ming; XU Qiang

    2006-01-01

    Water-blown polyurethane rigid foams are getting more and more attention, because the traditional blowing agent HCFC141b has already been abolished to prevent the ozone layer from destruction. However, the polyurethane rigid foams blown by water have serious defects, i.e. friability and resulting lower adhesion strength. Thus, the purpose of this study is to resolve the problems by chemical plastication. The maleate was added to polyol-premix containing water or to polyisocyanate,with both of which maleate does not react. To prove the reaction when polyol-premix and polyisocyanate were mixed, the model composite was synthesized and analyzed by IR, NMR and ESI (MS). Furthermore, a series of water-blown polyurethane rigid foams added different amount maleate were successfully prepared. By testing impact strength and adhesion strength of the foams, the actual effect of adding maleate was obtained.

  11. Elasticity and plasticity : foams near jamming

    NARCIS (Netherlands)

    Siemens, Alexander Oltmann Nicolaas

    2013-01-01

    Many materials, like foams, emulsions, suspensions and granular media obtain finite rigidity once their constituent particles are brought in contact. Nevertheless, all these materials can be made to flow by the application of relatively small stresses. By varying thermodynamic (temperature or densit

  12. Response of Polypmeric Foams and ABS Plastics to High Strain Rate Loading

    Science.gov (United States)

    Dick, Richard; Chang, Peter; Fourney, William

    1999-06-01

    The split-Hopkinson pressure bar (SHPB) technique was utilized to obtain high strain rate response data for low-density foams and solid ABS and polypropylene plastics. General Motors provided the materials for this study. These materials are used in the interior panels of automobiles. Because the foams have a very low impedance, polycarbonate bars were used to acquire the strain rate data in the 100 to 1600 per second range. An aluminum SHPB was used to obtain the solid plastics data that covered strain rates of 1000 to 4000 pre second. The experimental data indicate that the foams over the test range are only slightly strain rate dependent while the polypropylene appears to be strain rate independent above 1000 per second and the ABS plastics are strain rate independent above 3000 per second. The projectile length was varied to provide a wide range of induced strains ranging from 10 to 70 per cent for the foams and up to 20 per cent for the plastic materials.

  13. Plastic flow of foams and emulsions in a channel

    CERN Document Server

    Dollet, B; Sbragaglia, M

    2014-01-01

    In order to understand the flow profiles of complex fluids, a crucial issue concerns the emergence of spatial correlations among plastic rearrangements exhibiting cooperativity flow behaviour at the macroscopic level. In this paper, the rate of plastic events in a Poiseuille flow is experimentally measured on a confined foam in a Hele-Shaw geometry. The correlation with independently measured velocity profiles is quantified. To go beyond a limitation of the experiments, namely the presence of wall friction which complicates the relation between shear stress and shear rate, we compare the experiments with simulations of emulsion droplets based on the lattice-Boltzmann method, which are performed both with, and without, wall friction. Our results indicate a correlation between the localisation length of the velocity profiles and the localisation length of the number of plastic events. Finally, unprecedented results on the distribution of the orientation of plastic events show that there is a non-trivial correla...

  14. STOCHASTIC ELASTO-PLASTIC FRACTUREANALYSIS OF ALUMINUM FOAMS

    Institute of Scientific and Technical Information of China (English)

    Shiyong Sun; Haoran Chen; Xiaozhi Hu; Zhanjun Wu

    2009-01-01

    ModelI quasi-static nonlinear fracture of aluminum foams is analyzed by considering the effect of microscopic heterogeneity. Firstly, a continuum constitutive model is adopted to account for the plastic compressibility of the metallic foams. The yield strain modeled by a two-parameter Weibull-type function is adopted in the constitutive model. Then, a modified cohesive zone model is established to characterize the fracture behavior of aluminum foams with a cohesive zone ahead of the initial crack. The tensile traction versus local crack opening displacement relation is employed to describe the softening characteristics of the material. And a Weibull statistical model for peak bridging stress within the fracture process zone is used for considering microscopic heterogeneity of aluminum foams. Lastly, the influence of stochastic parameters on the curve of stress-strain is given. Numerical examples are given to illustrate the numerical model presented in this paper and the effects of WeibuU parameters and material properties on J-integral are discussed.

  15. 7 CFR 2902.17 - Plastic insulating foam for residential and commercial construction.

    Science.gov (United States)

    2010-01-01

    ... BIOBASED PRODUCTS FOR FEDERAL PROCUREMENT Designated Items § 2902.17 Plastic insulating foam for... preference for qualifying biobased plastic insulating foam for residential and commercial construction. By... items to be procured shall ensure that the relevant specifications require the use of biobased...

  16. Compressive and Fracture Properties of Syntactic Foam Filled with Hollow Plastic Bead(HPC)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The compressive mechanical properties of syntactic foams reinforced by hollow plastic beads were studied by the quasi-static compression test. The failure mechanism of syntactic foams was also investigated by macroscopic and microscopic observation on the fractured specimens. The experimental results show that the density of syntactic foams is still the key factor affecting their mechanical properties. The macroscopic and microscopic observation on the fractured specimens indicates that the main failure mode is the elastic-plastic collapse caused by shear.

  17. 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.

  18. A PVC-foam material model based on a thermodynamically elasto-plastic-damage framework exhibiting failure and crushing

    NARCIS (Netherlands)

    Gielen, A.W.J.

    2008-01-01

    A well known foam for naval sandwiches is PVC (polyvinyl chloride) foam. This foam exhibits elasto-damage behavior under tension and elasto-plastic behavior under compression. A proper material model is required for the prediction of the failure and post-failure behavior of these sandwiches during (

  19. Experimental investigation of supersonic radiation propagation in low-density plastic and copper-doped foams

    Institute of Scientific and Technical Information of China (English)

    JIANG; Shaoen; XU; Yan; DING; Yongkun; LAI; Dongxian; ZHEN

    2005-01-01

    Eight beams of 0.35 μm laser with pulse duration of 1 ns and total energy of 2 kJ enter into a hohlraum to create intense X-ray radiation of 140 eV on the Shenguang Ⅱ laser facility. Plastic foam (C6H12) and copper-doped foam (C6H12Cu0.394) with a density of 50 mg/cm3 are heated by X-ray radiation emitted from the hohlraum. The breakout time of the radiation wave is measured by a tri-chromatic streaked X-ray spectrometer (TCS) that consists of a set of three imaging pinholes and an array of three transmission gratings coupled with an X-ray streak camera (XSC). At one shot, the simultaneous measurements of the delay of the drive source and the radiation transport at two energies (210 eV, 840 eV) through the foam have been made for the first time. The experimental results indicate that the time delays vary with photon energies. With a transmission grating spectrometer (TGS), the spectra transmitting foams were measured, and the lower limit of the optical depth was measured. The radiation at energy of 210 eV propagates through plastic foam at a faster velocity, compared with the radiation at energy of 840 eV; while the results of copper-doped foam are reverse. The optical depth in the plastic foam is less than 1, and in the doped foam it is more than 1.

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

    Directory of Open Access Journals (Sweden)

    En-Bo Wei

    2014-11-01

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

  1. 化学氧化-铁离子覆盖改性聚氨酯泡沫塑料填料的特性%Characteristics of polyurethane(PU) foam plastics bio-carrier modified by chemical oxidation-surface covering with iron ion

    Institute of Scientific and Technical Information of China (English)

    杜振峰; 王芬; 成国栋; 林梦炜; 季民

    2012-01-01

    A surface modification method,chemical oxidation-surface covering with iron ion,was used to modify the polyurethane(PU) foam plastics bio-carrier.And surface properties of the bio-carrier,speed of biofilm formation,quantity of biological film and performance of treating wastewater were investigated before and after modification.The results showed that the ratio of the hydrophobic C-C,C-H bond on the surface of the modified bio-carrier was reduced by 15.81%,and the ratio of the hydrophilic C-O bond on the surface of the modified bio-carrier has increased by 16.17%.The dynamic contact angle of water against the bio-carrier surface was decreased by 10.46°.The surface roughness and hydrophilicity of the bio-carrier were enhanced.Comparing modified bio-carrier with the original bio-carrier,the quantity of biofilm increased by 60%,and the average growth rate of biological film increased by 50%.But the TTC-DHA of modified bio-carrier hardly increased.At the stage of biofilm formation,the performance of COD and ammonia removal of the modified bio-carrier was better than the original bio-carrier.After completion of biofilm formation,the removal efficiency of COD was almost the same,but the removal efficiency of ammonia increased by 10%.%采用化学氧化-铁离子覆盖改性方法对普通聚氨酯泡沫塑料填料进行改性,研究改性前后填料的表面特性、挂膜速度、生物膜量以及废水处理等性能。结果表明,改性填料表面的疏水性基团C—C、C—H比例下降了15.81%,亲水性基团C—O比例增加了16.17%,填料表面与蒸馏水的动态接触角减少了10.46°,其表面粗糙度以及亲水性提高。与未改性填料相比,改性填料生物膜量提高60%,生物膜平均每天生长量提高50%,但其生物膜脱氢酶活性并未明显提高。挂膜初期改性填料的COD和氨氮去除效果明显占优,挂膜完成后,改性填料对氨氮去除率比未改性填料高10%。

  2. Mechanisms of nanoclay-enhanced plastic foaming processes: effects of nanoclay intercalation and exfoliation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Anson; Wijnands, Stephan F. L.; Kuboki, Takashi; Park, Chul B., E-mail: park@mie.utoronto.ca [University of Toronto, Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering (Canada)

    2013-08-15

    The foaming behaviors of high-density polypropylene-nanoclay composites with intercalated and exfoliated nanoclay particles blown with carbon dioxide were examined via in situ observation of the foaming processes in a high-temperature/high-pressure view-cell. The intercalated nanoclay particles were 300-600 nm in length and 50-200 nm in thickness, while the exfoliated nanoclay particles were 100-200 nm in length and 1 nm in thickness. Contrary to common belief, it was discovered that intercalated nanoclay yielded higher cell density than exfoliated nanoclay despite its lower particle density. This was attributed to the higher tensile stresses generated around the larger and stiffer intercalated nanoclay particles, which led to increase in supersaturation level for cell nucleation. Also, the coupling agent used to exfoliate nanoclay would increase the affinity between polymer and surface of nanoclay particles. Consequently, the critical work needed for cell nucleation would be increased; pre-existing microvoids, which could act as seeds for cell nucleation, were also less likely to exist. Meanwhile, exfoliated nanoclay had better cell stabilization ability to prevent cell coalescence and cell coarsening. This investigation clarifies the roles of nanoclay in plastic foaming processes and provides guidance for the advancement of polymer nanocomposite foaming technology.

  3. Histopathological reaction over prosthesis surface covered with silicone and polyurethane foam implanted in rats

    OpenAIRE

    Jorge Wagenführ-Júnior; Jurandir Marcondes Ribas Filho; Marcelo Mazza do Nascimento; Fernanda Marcondes Ribas; Marcus Vinícius Wanka; Andressa de Lima Godoi

    2012-01-01

    PURPOSES: To evaluate whether polyurethane foam leads more intense foreign-body reaction than silicone foam. To compare the vascularization of the capsules surrounding the foam implants. To investigate if the capsule of polyurethane foam implanted has greater amount of collagen than that of silicone foam. METHODS: Sixty-four young male Wistar rats were allocated into two groups: polyurethane foam and silicone foam. Subcutaneous discs were implanted into the dorsum of the animals in both group...

  4. [Reducing nutrients loss by plastic film covering chemical fertilizers].

    Science.gov (United States)

    Chen, Huo-jun; Wei, Ze-bin; Wu, Qi-tang; Zeng, Shu-cai

    2010-03-01

    With the low utilization rate of fertilizers by crop and the growing amount of fertilizer usage,the agricultural non-point source pollution in China is becoming more and more serious. The field experiments planting corns were conducted, in which the applied chemical fertilizers were recovered with plastic film to realize the separation of fertilizers from rain water. In the experiments, the influences of different fertilizing treatments on the growing and production of sweet corn were observed. The fertilizer utilization rate and the nutrient contents in surface run-off water with and without the film covering were also determined. Results showed that, with only 70% of the normal amount of fertilizers,the sweet corn could already get high yield under the experimental soil conditions. Soil analysis after corn crops showed that the amounts of available N, P and K in the soil increased obviously with the film-covering, and the decreasing order was: 100% fertilizers with film-covering > 70% fertilizers with film-covering > 100% fertilizers, 70% fertilizers > no fertilizer. The average utilization coefficients of fertilizers by the crop were 42%-87%, 0%-3%, 5%-15% respectively for N, P and K. It was higher with film-covering than that without covering, especially for the high fertilization treatment. Analysis of water samples collected for eight run-off events showed that, without film-covering, N, P and K average concentrations in the runoff waters with fertilizations were 27.72, 2.70 and 7.07 mg x L(-1), respectively. And they were reduced respectively by 39.54%, 28.05%, 43.74% with the film-covering. This can give significant benefits to the decrease of agricultural non-point source pollution and water eutrophication.

  5. Hydrothermal deposition of manganese dioxide nanosheets on electrodeposited graphene covered nickel foam as a high-performance electrode for supercapacitors

    Science.gov (United States)

    Li, Yiju; Cao, Dianxue; Wang, Ying; Yang, Sainan; Zhang, Dongming; Ye, Ke; Cheng, Kui; Yin, Jinling; Wang, Guiling; Xu, Yang

    2015-04-01

    In this paper, the graphene oxide nanosheets are simultaneously reduced and deposited on nickel foam (denoted as Ni-foam@GNS) by one step electrodeposition method. The interconnected crumpled graphene nanosheets grown on Ni foam serve as a three-dimensional (3D) conductive skeleton for hydrothermal deposition of MnO2 nanosheets by in-situ redox reaction. The MnO2 nanosheets anchored on the graphene covered nickel foam (denoted as Ni-foam@GNS@MnO2) show unique 3D porous interconnected networks. The samples are characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), N2 adsorption-desorption measurements and fourier transform infrared spectroscopy (FT-IR). The capacitive performances are researched by cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS). The results reveal that the Ni-foam@GNS@MnO2 electrode exhibits a high specific capacitance of 462 F g-1 at 0.5 A g-1 and excellent capacitance retention of 93.1% after 5000 cycles at 10 A g-1. Furthermore, the Ni-foam@GNS@MnO2 electrode delivers a high energy density of 26.1 Wh kg-1 even at a high power density of 3981 W kg-1. These results demonstrate that the Ni-foam@GNS@MnO2 composite offers great promise in large-scale energy storage device applications.

  6. Study Progress of Polylactic Acid Foamed Plastics%聚乳酸泡沫塑料的研究进展

    Institute of Scientific and Technical Information of China (English)

    杨志云; 蔡业彬; 张铱鈖

    2014-01-01

    This paper reviews the progress in studies on polylactic acid foamed plastics ,namely the environmental foamed plastics .It in-cludes the studies researched by the domestic and overseas scholars on the polylactic acid foaming performance ,process conditions ,bubble hole form and so on .Some existing problems are put forward and the study on polylactic acid foamed technology in the future is prospected in this paper .Continuous extrusion of microcellular foam of polyactic (PLA) will be the goal and direction in the future .To achieve the goal will accelerate the industrialization process of microcellular plastics polyactic (PLA) .%文章介绍了环保型泡沫塑料---聚乳酸泡沫塑料当前的研究进展,主要包括国内外学者对聚乳酸的发泡性能、工艺条件和泡孔形态等研究,并提出了目前存在的问题,对未来聚乳酸发泡技术的研究进行了展望。连续挤出微孔的聚乳酸泡沫塑料将成为未来的研究热点和方向,其不断发展也将加快推动聚乳酸微孔塑料的工业化进程。

  7. Size selective isocyanate aerosols personal air sampling using porous plastic foams

    Energy Technology Data Exchange (ETDEWEB)

    Cong Khanh Huynh; Trinh Vu Duc, E-mail: chuynh@hospvd.c [Institut Universitaire Romand de Sante au Travail (IST), 21 rue du Bugnon - CH-1011 Lausanne (Switzerland)

    2009-02-01

    As part of a European project (SMT4-CT96-2137), various European institutions specialized in occupational hygiene (BGIA, HSL, IOM, INRS, IST, Ambiente e Lavoro) have established a program of scientific collaboration to develop one or more prototypes of European personal samplers for the collection of simultaneous three dust fractions: inhalable, thoracic and respirable. These samplers based on existing sampling heads (IOM, GSP and cassettes) use Polyurethane Plastic Foam (PUF) according to their porosity to support sampling and separator size of the particles. In this study, the authors present an original application of size selective personal air sampling using chemical impregnated PUF to perform isocyanate aerosols capturing and derivatizing in industrial spray-painting shops.

  8. Corn Growth as Affected by Plastic Cover Under Drip Irrigation Condition in the Desert

    Institute of Scientific and Technical Information of China (English)

    WANGXUE-FENG; U.SHANI

    1994-01-01

    Plastic cover,as a method to minimize soil water evaporation and improve water use efficiency,was used for corn during the whole growing period in a desert area.Field Studies were conducted to determine the effect of plastic covering nmanagement on corn growth and rooting pattern and its relationship with changes in climate.Four treatments.0) bared soil without cover,1) covering one side of the crop,2) covering both sides of the crop,and 3) covering the surface totally,were established on a sandy loam soil.Results showed that treatment 0 was significantly different from others and revealed that plastic covering was not always good to corn growht.Improper usage of plastic cover might weaken root development and thereafter lower the total yield of the crop.Suitable practices cvombining different methods discussed could not only improve water use efficiency but also increase the crop yield.

  9. Histopathological reaction over prosthesis surface covered with silicone and polyurethane foam implanted in rats.

    Science.gov (United States)

    Wagenführ-Júnior, Jorge; Ribas Filho, Jurandir Marcondes; Nascimento, Marcelo Mazza do; Ribas, Fernanda Marcondes; Wanka, Marcus Vinícius; Godoi, Andressa de Lima

    2012-12-01

    To evaluate whether polyurethane foam leads more intense foreign-body reaction than silicone foam. To compare the vascularization of the capsules surrounding the foam implants. To investigate if the capsule of polyurethane foam implanted has greater amount of collagen than that of silicone foam. Sixty-four young male Wistar rats were allocated into two groups: polyurethane foam and silicone foam. Subcutaneous discs were implanted into the dorsum of the animals in both groups. The capsules were assessed 28 days, two months, three months and six months postoperatively. Microscopic analysis with H&E stain was performed to evaluate the acute and chronic inflammatory process, foreign-body reaction and neovascularization. The analysis with picrosirius red was performed using the ImageProPlus software, to measure the number of vessels and collagen types I and III. There were no statistical differences between the two groups regarding the acute and chronic inflammatory processes. All rats from the polyurethane group, in all times, exhibited moderate or intense foreign-body reaction, with statistic significant difference (p=0.046) when compared with the silicone group, in which the reaction was either mild or nonexistent at two months. Vascular proliferation was significantly different between the groups at 28 days (p=0.0002), with the polyurethane group displaying greater neovascularization with H&E stain. Similar results were obtained with picrosirius red, which revealed in the polyurethane group a much greater number of vessels than in the silicone group (p=0.001). The collagen area was larger in the polyurethane group, significantly at 28 days (p=0.001) and at two months (p=0.030). Polyurethane foam elicited more intense foreign-body reaction when compared with silicone foam. The number of vessels was higher in the capsules of the polyurethane foam implants 28 days after the operation. The capsule of the polyurethane foam implants showed a greater amount of collagen

  10. A finite deformation coupled plastic-damage model for simulating fracture of metal foams

    OpenAIRE

    Pan, Hao; Abu Al-Rub, Rashid

    2014-01-01

    Metal foams are a novel class of lightweight materials with unique mechanical, thermal, and acoustical properties. The low ductility of metal foams hinders the possibilities of applying secondary forming techniques to shape metal foam sandwich panels into desired industrial components. An important factor is the limited studies on their macroscopic damage and fracture behavior under complex loading conditions. There exist numerous mechanistic micromechanics models describing the fracture beha...

  11. Anatomy, chlorophyll content and photosynthetic potential in grapevine leaves under plastic cover

    Directory of Open Access Journals (Sweden)

    Geraldo Chavarria

    2012-09-01

    Full Text Available The present study evaluated the anatomy, chlorophyll content and photosynthetic potential of grapevine leaves grown under plastic cover. The experiment was carried out in vineyards of Moscato Giallo cultivar covered and uncovered with plastic. A block design with 10 selected plants was used for each area (covered and uncovered. Twelve leaves (six of them fully exposed to solar radiation and six grown under shaded conditions were collected from each area and were fixed and analyzed microscopically (thickness of the adaxial and abaxial epidermis and of the palisade and spongy parenchymas. Chlorophyll content and photosynthetic potential were determined in the vineyard at veraison and after harvest. Plastic covering increased the thickness of the palisade parenchyma in exposed and shaded leaves due to solar radiation restriction. However, the leaves from the covered vineyard did not have the same response to the restriction of solar radiation, as observed in the uncovered vineyard. The thickness of the adaxial and abaxial epidermis and of the spongy parenchyma did not vary due to solar radiation restriction. Chlorophyll content increased in the leaves of covered plants. The photosynthetic potential of the vines is not affected by solar radiation restriction imposed by plastic cover due to anatomical modification in leaves.

  12. Suffocation caused by plastic wrap covering the face combined with nitrous oxide inhalation

    DEFF Research Database (Denmark)

    Leth, Peter Mygind; Astrup, Birgitte Schmidt

    2017-01-01

    Suicide using a combination of a plastic bag over the head and inhalation of a non-irritating gas, such as helium, argon or nitrogen, has been reported in the literature. Here an unusual suicide method in a 17-year old man by suffocation from covering the face with household plastic wrap, combined...... with headspace-gas chromatography-mass spectrometry (headspace-GCMS). The cause of death was assumed to be suffocation caused by plastic wrap covering the face, combined with nitrous oxide inhalation. Suicide was suspected because of a history of depression for several months. Nitrous oxide, also known...... as laughing gas, has a euphoric effect and is used as a recreational inhalant drug that can be purchased legally. Deaths caused by recreational nitrous oxide abuse are rare but may occur if used in combination with a plastic bag over the head. This is the first report of suicide by suffocation by external...

  13. Silicone foam molding method for sealing timing belt cover gasket; Timing belt gasket no happo silicone gomu tofu gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Y.; Kagosaki, T.; Omura, S.; Yamaguchi, H. [Toyota Motor Corp., Aichi (Japan)

    1995-04-20

    An automated assembly of a timing belt cover gasket succeeded by changing a gasket material from molding rubber to silicone foam rubber and making a coating application process with the change. Since a conventional molding rubber gasket was unstable to shape and difficult to integrate in the automation, a method was examined for applying a liquid silicone foam rubber, a building material. A silicone foam rubber as a building material had problems such that reaction was fast after two liquids were mixed, that hardening occurred in the mixed part, and that the viscosity was so low as to make a 3-dimensional application impossible. Consequently, a material was developed for a two-liquid heat setting type that commenced reaction by heating. An application process excellent in quality and yield was completed. In the system containing a device for mixing and discharging two liquids, by enlarging the bore diameter of a discharge nozzle, cutting liquid at the tip end of the nozzle, making a mixer with a small number of revolution and small capacity, using the material in which reaction starting temperature was raised to suppress the reaction inside the mixer, and so on. Thus, the automation was successfully carried out. 16 figs., 1 tab.

  14. Microclimatic changes caused by different plastic coverings in greenhouses cultivated with cherry tomato in southern Brazil

    Directory of Open Access Journals (Sweden)

    Ester Holcman

    2015-06-01

    Full Text Available In regions with intense solar radiation it is common the use of aluminated covers in greenhouses, with the aim of reducing the inside temperature. However, the use of these covers reduces photosynthetic active radiation (PAR transmitted into the greenhouse. The objective of the present study was to evaluate the influence of different covers on microclimate in greenhouses cultivated with cherry tomato during three growing seasons. The environment I was covered with plastic film anti-UV and with thermo-reflective screen (40% disposed internally. The environment II was covered with diffusive plastic film (55%. The transmitted solar radiation to the interior of covered environments was, on average, 5.5 MJ m-2 day-1 in the environment I and 8.2 MJ m-2 day-1 in environment II. The air temperature in environment II was, on average, 1°C higher than external conditions. The highest difference for the relative humidity (RH was also observed between environment II and the outside conditions, with 10.7% for the minimum RH during the first growing period. Considering all growing periods, the diffusive plastic film provided higher solar energy availability inside the greenhouse than the plastic film with thermo-reflective screen, without causing major changes in air temperature and relative humidity, and promoting greater productivity of tomato grown under this environment for the three periods evaluated.

  15. 21 CFR 178.3010 - Adjuvant substances used in the manufacture of foamed plastics.

    Science.gov (United States)

    2010-04-01

    ...: ADJUVANTS, PRODUCTION AIDS, AND SANITIZERS Certain Adjuvants and Production Aids § 178.3010 Adjuvant... weight of finished foamed polyethylene. 1,1-Difluoroethane (CAS Reg. No. 75-37-6) For use as a blowing...

  16. Mapping Rural Areas with Widespread Plastic Covered Vineyards Using True Color Aerial Data

    Directory of Open Access Journals (Sweden)

    Eufemia Tarantino

    2012-06-01

    Full Text Available Plastic covering is used worldwide to protect crops against damaging growing conditions. This agricultural practice raises some controversial issues. While it significantly impacts on local economic vitality, plasticulture also shows several environmental affects. In the Apulia Region (Italy the wide-spreading of artificial plastic coverings for vineyard protection has showed negative consequences on the hydrogeological balance of soils as well as on the visual quality of rural landscape. In order to monitor and manage this phenomenon, a detailed site mapping has become essential. In this study an efficient object-based classification procedure from Very High Spatial Resolution (VHSR true color aerial data was developed on eight test areas located in the Ionian area of the Apulia Region in order to support the updating of the existing land use database aimed at plastic covered vineyard monitoring.

  17. The contribution of Landsat 8 TIRS sensor data to the identification of plastic covered vineyards

    Science.gov (United States)

    Novelli, Antonio; Tarantino, Eufemia

    2015-06-01

    Plastic covering is a common practice in agricultural fields. From an agronomic point of view, plastic coverings offer many advantages against unfavourable growing conditions. This explains their widespread utilization with consequent positive impact on local economy. On the other hand, plasticulture raises both environmental and landscape issues. In the Apulia Region (Italy) the wide implementation of such practice generally relates to vineyard cultivation. Continuous vineyard protection has resulted in negative effects on the hydrogeological balance of soils, causing a deep modification of the traditional rural landscape and therefore affecting its quality. To guarantee both the protection of local economy as well as the preservation of local environment and landscape features, a detailed site mapping of the areas involved is necessary. Indeed, the quantification of this phenomenon is essential in the periodic updating of the existing land use database and in the development of local policies. In this study we evaluate the potential of the novel Thermal Infrared Sensor bands (TIRS) provided by the LANDSAT 8 mission in plasticulture discrimination. Using the evident anomaly retrieved in the study area on the Quality Assessment (QA) band, a fast procedure involving TIRS data was developed, proposing a new index (Plastic Surface Index- PSI) able to emphasize plasticulture. For the aim of this study, two different acquisition dates on a test area in the Apulia region (Italy) were analyzed, one in the growing season with high plastic covering density and one in the post-harvest period with low plastic cover density.

  18. 纳米片层石墨填充聚氨酯泡沫塑料的制备和电学性能%Preparation and Electrical properties of Polyurethane/graphite Nanosheet Foam Plastics

    Institute of Scientific and Technical Information of China (English)

    CHEN Dan-qing; CAI Jin-chao; CHEN Guo-hua

    2008-01-01

    Using polyester polyol and diphenylmethane diisocyanate(MDI)as basic component,and using graphite as conduct.ive filler,polyurethane/graphite nanosheet foam plastics is produced by filling mould curing reaction.Also the electrical properties of the foam plastics are studied.

  19. INVESTIGATION ON THE FRACTURE PROPERTIES[1mm] OF POLYURETHANE RIGID FOAM PLASTICS%聚氨酯泡沫塑料的强度与断裂韧性

    Institute of Scientific and Technical Information of China (English)

    卢子兴; 高镇同; 朱汪鲲; 寇长河

    2000-01-01

    As one kind of structural material, it is indispensable to undergotensile loadingin use for high-density foam plastics. So, it is an important work toinvestigate its tensile fracture properties and to determine its tensilefracture strength as well as the fracture toughness for engineeringapplications. In this paper,the tensile experiments have been done for the polyurethane rigid foam plastics of threedifferent densities. Their tensile fracture strength and fracturetoughness were determined byspecimens without and with a notch, respectively. In order to investigate thetensile fracture mechanism, the SEM analyses have been conducted forthe broken specimens. In addition, the theoretical prediction for fracturetoughness of polyurethane rigid foam plastics is also discussed in this paper. Finally,the following conclusions can be drawn:   1) The Young's modulus and tensile fracture strength of polyurethane rigid foamplastics increase with its density.   2) The fracture toughness of polyurethane rigid foam plastics alsoincreases with itsdensity.   3) It is shown by SEM analyses that the cell failure of foam plasticsgenerally originates from the edge of penetrating holes on the cell walland its breaking basically belongs to one kind of britle fracture.   4) The fracture toughness of polyurethane rigid foam plastics has a direct bearing onthe cell size of it.   5) The micro-defects (or voids) exert a larger effect on the practicalstrength of foam plastics, but they hardly affect its fracturetoughness.%针对3种密度的聚氨酯泡沫塑料进行了拉伸实验.通过无缺口试件确定了3种密度泡沫塑料的拉伸断裂强度, 而利用有缺口试件确定了这些材料的拉伸断裂韧性.为了研究高密度泡沫塑料的拉伸断裂机制, 还对破坏后试件进行了扫描电镜分析.此外,还简要讨论了泡沫塑料拉伸断裂力学性能的理论预测问题.

  20. The Foam Plastics Characteristics and Application of Rigid Polyurethane%硬质聚氨酯泡沫塑料特性及其应用

    Institute of Scientific and Technical Information of China (English)

    张禹; 孙凤彬; 李永毅; 王长春

    2014-01-01

    This article introduces the bubble pore structure fo-rm of rigid polyurethane foam plastics, probes into the rigid polyurethane foam physical properties of thermal insulation and dynamic properties, and introduces the application in the project structure cold-proof and vibration isolation.%本文介绍了硬质聚氨酯泡沫塑料的泡孔结构形式,探讨了硬质聚氨酯泡沫塑料保温隔热等物理特性以及动力性能,介绍了其在工程结构防寒、隔振中的应用。

  1. Determination of Trace Amounts of Gold in Soil Sample Using Plastic Foam Enrichment-ICP-MS Method%泡塑富集ICP-MS测定土壤中痕量金

    Institute of Scientific and Technical Information of China (English)

    余波

    2008-01-01

    The aim of this study is to determine the trace amount of gold in soil sample using plastic foam enrichment-ICP-MS method. The national standard reference materials including GAu-2,GAu-10,GAu-11 and GAu-13 were used for parallel determination by ICPMS. The results showed that the method performed well in detection limit, precision and accuracy, indicating that the plastic foam enrichment-ICP-MS method could be used to determine the trace amounts of gold in soil sample.

  2. A plastic indentation model for sandwich beams with metallic foam cores

    Institute of Scientific and Technical Information of China (English)

    Zhong-You Xie; Ji-Lin Yu; Zhi-Jun Zheng

    2011-01-01

    Light weight high performance sandwich composite structures have been used extensively in various load bearing applications.Experiments have shown that the indentation significantly reduces the load bearing capacity of sandwiched beams.In this paper,the indentation behavior of foam core sandwich beams without considering the globally axial and flexural deformation was analyzed using the principle of virtual velocities.A concisely theoretical solution of loading capacity and denting profile was presented.The denting load was found to be proportional to the square root of the denting depth.A finite element model was established to verify the prediction of the model.The load-indentation curves and the profiles of the dented zone predicted by theoretical model and numerical simulation are in good agreement.

  3. 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 ...

  4. Effect of Covered Metallic Stents Compared With Plastic Stents on Benign Biliary Stricture Resolution

    Science.gov (United States)

    Coté, Gregory A.; Slivka, Adam; Tarnasky, Paul; Mullady, Daniel K.; Elmunzer, B. Joseph; Elta, Grace; Fogel, Evan; Lehman, Glen; McHenry, Lee; Romagnuolo, Joseph; Menon, Shyam; Siddiqui, Uzma D.; Watkins, James; Lynch, Sheryl; Denski, Cheryl; Xu, Huiping; Sherman, Stuart

    2017-01-01

    IMPORTANCE Endoscopic placement of multiple plastic stents in parallel is the first-line treatment for most benign biliary strictures; it is possible that fully covered, self-expandable metallic stents (cSEMS) may require fewer endoscopic retrograde cholangiopancreatography procedures (ERCPs) to achieve resolution. OBJECTIVE To assess whether use of cSEMS is noninferior to plastic stents with respect to stricture resolution. DESIGN, SETTING, AND PARTICIPANTS Multicenter (8 endoscopic referral centers), open-label, parallel, randomized clinical trial involving patients with treatment-naive, benign biliary strictures (N = 112) due to orthotopic liver transplant (n = 73), chronic pancreatitis (n = 35), or postoperative injury (n = 4), who were enrolled between April 2011 and September 2014 (with follow-up ending October 2015). Patients with a bile duct diameter less than 6 mm and those with an intact gallbladder in whom the cystic duct would be overlapped by a cSEMS were excluded. INTERVENTIONS Patients (N = 112) were randomized to receive multiple plastic stents or a single cSEMS, stratified by stricture etiology and with endoscopic reassessment for resolution every 3 months (plastic stents) or every 6 months (cSEMS). Patients were followed up for 12 months after stricture resolution to assess for recurrence. MAIN OUTCOMES AND MEASURES Primary outcome was stricture resolution after no more than 12 months of endoscopic therapy. The sample size was estimated based on the noninferiority of cSEMS to plastic stents, with a noninferiority margin of −15%. RESULTS There were 55 patients in the plastic stent group (mean [SD] age, 57 [11] years; 17 women [31%]) and 57 patients in the cSEMS group (mean [SD] age, 55 [10] years; 19 women [33%]). Compared with plastic stents (41/48, 85.4%), the cSEMS resolution rate was 50 of 54 patients (92.6%), with a rate difference of 7.2% (1-sided 95% CI, −3.0% to ∞; P < .001). Given the prespecified noninferiority margin of −15%, the

  5. Preparation of Rigid Cross-Linking PVC Foam Plastics%硬质交联PVC泡沫塑料的制备

    Institute of Scientific and Technical Information of China (English)

    王雁国; 汪艳; 张慧

    2014-01-01

    Based on polyvinyl chloride(PVC) resin,rigid cross-linking PVC foam plastics with special performance were prepared by isocyanate and melamine which were used as the cross-linking agent and maleic anhydride which was used as the grafting agent. It is confirmed that the cross-linking reaction happen in the boiling process phase by infrared spectrum analysis, thermal gravimetric analysis,thermal mechanical analysis and gel content measurement. It also shows that the glass transition temperature of the foam plastics is at about 180℃. Dosage of maleic anhydride was studied on the influence of the gel content of the foam plastics,the amount of maleic anhydride has less effect on the degree of cross-linking in plasticization and molding phase and the gel content of the foam plastics is increased with the increase of dosage of maleic anhydride. Bubble pore diameter were measured by optical microscope. It shows that the distribution of bubble pore diameter are homogeneous,the bubble pore diameter of the foam plastics for the density of 60 kg/m3 are mainly distributed in 100~130 μm and the density of 90 kg/m3 are mainly distributed in 70~80 μm. By the determination of the mechanical properties of the foam plastics,it shows that the foam plastics has the same mechanical properties as the Swiss Airex C70 products.%以聚氯乙烯(PVC)为基体,马来酸酐为接枝剂,异氰酸酯、三聚氰胺为交联剂,制备出性能优异的硬质交联PVC泡沫塑料;通过红外光谱、热失重和热机械分析及凝胶含量测定对硬质交联PVC泡沫塑料进行分析,证实交联反应发生在水煮工艺阶段,玻璃化转变温度在180℃左右;研究了马来酸酐用量对硬质交联PVC泡沫塑料凝胶含量的影响,马来酸酐的用量在塑化成型阶段对交联度的影响较小,硬质交联PVC泡沫塑料的凝胶含量随着马来酸酐用量的增加而增大;用光学显微镜对硬质交联PVC泡沫塑料的泡孔直径进行了

  6. 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.

  7. 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.

  8. Assessing the suitability of recycled plastics used as agricultural soil covers: migration study and experimental harvest.

    Science.gov (United States)

    Nerín, C; Batlle, R

    1999-01-01

    The present work is focused on evaluating the suitability of recycling postconsumer agricultural plastic films again for the same use. The criteria to assess the suitability was based on migration study. Both overall and specific migration tests were performed, and the results obtained (ranging from 0.14 to 1.27 mg/dm(2) for overall migration and from not detectable to 6.98 microg/dm(2) for specific migration) show how, from this point of view, the recycled material can be safely proposed to be used again as agricultural soil covers. A theoretical discussion about the migration process is also presented and a simple mathematical model was applied to the data obtained, showing how total migration which is experimentally detected is theoretically predictable. These conclusions found were used to design and develop a controlled crop of tomato by using this recycled film. The use of the recycled plastic in the whole process and the behavior and properties of the pesticides absorbed in the postconsumer film are discussed.

  9. The treatment of a polyurethane rigid foam floor piece by Ger van Elk: a study in the conservation of plastics

    NARCIS (Netherlands)

    Snijders, E.; Weerdenbrug, S.; Timmermans, R.; Bridgland, J.

    2011-01-01

    Plint serie [Baseboard Series] (1967) by the Dutch artist Ger van Elk is a floor sculpture of painted polyurethane foam in the collection of the Stedelijk Museum Amsterdam. By 2007, the artwork was in a bad state: a point had broken off and there were dents and holes in the polyurethane foam and lac

  10. 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

  11. The Effect of Plastic Cover on Regulation of Vital Signs in Preterm Infants: A Randomized Cross-over Clinical Trial

    Directory of Open Access Journals (Sweden)

    Leila Valizadeh

    2017-06-01

    Full Text Available Background: Considering the susceptibility of preterm infants to disturbances of vital signs, this study was conducted to investigate the effects of using plastic covers on regulation of vital signs in preterm neonates.Methods: This randomized, cross-over, clinical trial was carried out on 80 preterm infants admitted to neonatal intensive care unit (NICU of Taleghani Hospital, Tabriz, Iran. The study was conducted in two days (on the second and third days of the infants’ life. In group 1, plastic cover was used during the first day followed by the use of blanket on the second day, while the order was reversed in group 2. Digital thermometer was used to measure the infants’ axillary temperature. Heart rate and oxygen saturation were measured through monitoring. To analyze the data, descriptive (Mean and SE, 95%CI and inferential statistics (repeated measurement and ANCOVA tests were used in SPSS version 13 and MiniTab software.Results: Fourteen infants who were covered with blanket were found to suffer from hypothermia, while no infant with a plastic cover encountered this problem. The percentage of arterial blood oxygen saturation in the group with plastic covers was higher, and as a result, the infants received less oxygen supplements. However, no statistically significant differences were observed in heart rate between the groups.Conclusion: Use of plastic cover during NICU stay prevented hypothermia in premature infants, with the arterial blood oxygen saturation being within the normal limits. Yet, it did not seem to have a significant effect on other vital signs.

  12. Optimising the use of plastic protective covers in field grown melon on a farm scale

    Directory of Open Access Journals (Sweden)

    Paolo Benincasa

    2014-01-01

    Full Text Available This in-farm research study was aimed at evaluating new strategies in the use of plastic protective covers in field grown melon in order to expand the production period and reduce costs. Four experiments were set up in 2010 and repeated in 2011 in Central Italy, in an inland region with a temperate climate. We evaluated: i the use of high tunnels for two growing cycles per year, i.e. for very early and very late production (target transplanting in late winter and mid-summer, respectively, for either one year or two consecutive years, and the use of grafted plants in the second year as an alternative to normal plants to prevent soil born diseases; ii the use of ethylene-vinyl-acetate film low tunnels alone or combined with non-woven floating row covers for transplanting in early spring; iii the use of non-woven low tunnels for transplanting in mid-spring; iv the use of biodegradable and conventional polyethylene ground mulch films, both in the presence of nonwoven low tunnels. As far as the non-woven cover is concerned, we adopted the strategy of removing later with respect to usual practices, i.e. ten days after the onset of first pistillate flowers. This was based on the evidence that covers hamper honeybee circulation, which may be exploited on a farm-scale to delay pollination until an adequate number of pistillate flowers set, in order to shorten scaled fruit ripening and harvest. Our results demonstrate that high tunnels may be used for at least four consecutive melon growing cycles (early and late productions for two years with good off-season yields and no appreciable drawbacks in terms of disease scale-up, irrespective of the use of normal or grafted plants. The non-woven low tunnel was effective in hampering honeybee circulation and its delayed removal allowed the harvest period to be halved, a more uniform fruit size to be obtained, and labour productivity of harvest to be increased. This had positive implications on the management of

  13. Utilization of profilometry, SEM, AFM and contact angle measurements in describing surfaces of plastic floor coverings and explaining their cleanability

    Science.gov (United States)

    Kuisma, R.; Pesonen-Leinonen, E.; Redsven, I.; Kymäläinen, H.-R.; Saarikoski, I.; Sjöberg, A.-M.; Hautala, M.

    2005-06-01

    The tendency to soil and cleanability of ten commercial plastic floor coverings: eight vinyl (PVC) floor coverings, one vinyl composite tile and one plastic composite tile, were examined. Floor coverings were soiled with inorganic, organic and biological soil. The cleanability was measured both by bioluminescence of ATP (adenosine triphosphate) and colorimetrically. The surface topography was studied by AFM, SEM and with a profilometer. From the 2D- and 3D-profilometric measurements several characteristic parameters of the surface profiles were extracted. The tendency to soil and cleanability were compared with the characteristics of the surface. A weak correlation was found between roughness and soilability but no correlation between roughness and cleanability. Roughness had no correlation with contact angle.

  14. The effect of coverings, including plastic bags and wraps, on mortality and morbidity in preterm and full-term neonates.

    Science.gov (United States)

    Oatley, H K; Blencowe, H; Lawn, J E

    2016-05-01

    Neonatal hypothermia is an important risk factor for mortality and morbidity, and is common even in temperate climates. We conducted a systematic review to determine whether plastic coverings, used immediately following delivery, were effective in reducing the incidence of mortality, hypothermia and morbidity. A total of 26 studies (2271 preterm and 1003 term neonates) were included. Meta-analyses were conducted as appropriate. Plastic wraps were associated with a reduction in hypothermia in preterm (⩽29 weeks; risk ratio (RR)=0.57; 95% confidence interval (CI) 0.46 to 0.71) and term neonates (RR=0.76; 95% CI 0.60 to 0.96). No significant reduction in neonatal mortality or morbidity was found; however, the studies were underpowered for these outcomes. For neonates, especially preterm, plastic wraps combined with other environmental heat sources are effective in reducing hypothermia during stabilization and transfer within hospital. Further research is needed to quantify the effects on mortality or morbidity, and investigate the use of plastic coverings outside hospital settings or without additional heat sources.

  15. The effect of coverings, including plastic bags and wraps, on mortality and morbidity in preterm and full-term neonates

    Science.gov (United States)

    Oatley, H K; Blencowe, H; Lawn, J E

    2016-01-01

    Neonatal hypothermia is an important risk factor for mortality and morbidity, and is common even in temperate climates. We conducted a systematic review to determine whether plastic coverings, used immediately following delivery, were effective in reducing the incidence of mortality, hypothermia and morbidity. A total of 26 studies (2271 preterm and 1003 term neonates) were included. Meta-analyses were conducted as appropriate. Plastic wraps were associated with a reduction in hypothermia in preterm (⩽29 weeks; risk ratio (RR)=0.57; 95% confidence interval (CI) 0.46 to 0.71) and term neonates (RR=0.76; 95% CI 0.60 to 0.96). No significant reduction in neonatal mortality or morbidity was found; however, the studies were underpowered for these outcomes. For neonates, especially preterm, plastic wraps combined with other environmental heat sources are effective in reducing hypothermia during stabilization and transfer within hospital. Further research is needed to quantify the effects on mortality or morbidity, and investigate the use of plastic coverings outside hospital settings or without additional heat sources. PMID:27109095

  16. 腰果酚改性焦油粗酚酚醛泡沫塑料的研究%Study on Cardanol Modiifed Tar Crude Phenol Phenolic Foam Plastics

    Institute of Scientific and Technical Information of China (English)

    李红标; 张晓丹; 沈国鹏

    2014-01-01

    为降低酚醛泡沫塑料的成本,改善其性能,以焦油粗酚、苯酚、多聚甲醛为原材料,腰果酚为改性剂,合成可发性腰果酚改性焦油粗酚酚醛树脂,发泡制备出腰果酚改性焦油粗酚酚醛泡沫塑料。研究了腰果酚用量对改性焦油粗酚酚醛泡沫塑料保温性能、阻燃性能、吸水率、力学性能和耐热稳定性等的影响,并通过傅立叶变换红外光谱仪对合成改性焦油粗酚酚醛树脂进行了表征,通过生物显微镜、热重分析仪对改性焦油粗酚酚醛泡沫塑料的微观结构和耐热稳定性进行表征。结果表明,腰果酚的加入使改性焦油粗酚酚醛泡沫塑料的综合性能有较大改善,当腰果酚占混合酚的质量分数为15%时,改性焦油粗酚酚醛泡沫塑料的综合性能最佳,吸水率为4.51%,压缩强度为0.31 MPa,弯曲强度为0.55 MPa,导热系数为0.036 W/(m · K),极限氧指数为35.2%。改性焦油粗酚酚醛泡沫塑料的保温、阻燃性能和耐热稳定性较好,泡孔致密均匀。%In order to reduce the cost and improve the performance of phenolic foam plastics,the foamable tar crude phenol phenolic resin modified with cardanol was synthesized by using tar crude phenol,phenol,paraformaldehyde as materials,cardanol as modifier. Then tar crude phenol phenolic foam plastics modified with cardanol was prepared by foaming. The effects of the amount of cardanol on heat preservation,fire retardancy,water absorption,mechanical properties and thermal stabilities of the modified foam plastics were investigated,the modified tar crude phenol phenolic resin was characterized by fourier transform infrared spectrometer, the microscopic structure and thermal stabilities of the modified foam plastics were characterized by biological microscope and thermo gravimetric analyzer. The results show that the comprehensive properties of the modified foam plastics is improved greatly by cardanol

  17. Structural applications of metal foams considering material and geometrical uncertainty

    Science.gov (United States)

    Moradi, Mohammadreza

    Metal foam is a relatively new and potentially revolutionary material that allows for components to be replaced with elements capable of large energy dissipation, or components to be stiffened with elements which will generate significant supplementary energy dissipation when buckling occurs. Metal foams provide a means to explore reconfiguring steel structures to mitigate cross-section buckling in many cases and dramatically increase energy dissipation in all cases. The microstructure of metal foams consists of solid and void phases. These voids have random shape and size. Therefore, randomness ,which is introduced into metal foams during the manufacturing processes, creating more uncertainty in the behavior of metal foams compared to solid steel. Therefore, studying uncertainty in the performance metrics of structures which have metal foams is more crucial than for conventional structures. Therefore, in this study, structural application of metal foams considering material and geometrical uncertainty is presented. This study applies the Sobol' decomposition of a function of many random variables to different problem in structural mechanics. First, the Sobol' decomposition itself is reviewed and extended to cover the case in which the input random variables have Gaussian distribution. Then two examples are given for a polynomial function of 3 random variables and the collapse load of a two story frame. In the structural example, the Sobol' decomposition is used to decompose the variance of the response, the collapse load, into contributions from the individual input variables. This decomposition reveals the relative importance of the individual member yield stresses in determining the collapse load of the frame. In applying the Sobol' decomposition to this structural problem the following issues are addressed: calculation of the components of the Sobol' decomposition by Monte Carlo simulation; the effect of input distribution on the Sobol' decomposition

  18. Lost Foam Casting Process of Gray Cast Iron Flywheel Cover%灰铸铁飞轮壳体消失模铸造工艺

    Institute of Scientific and Technical Information of China (English)

    孟兆亚; 王建民; 史家全; 孙洪超

    2011-01-01

    以灰铸铁飞轮壳体为例,系统的阐述了消失模铸造的工艺过程和工艺参数.采用阶梯式浇注系统,雨淋式加沙法,浇道比为F内∶F横∶F直=1.0∶1.2:1.4,浇注时负压为0.040~0.055 MPa.浇注温度控制在1 470~1 480℃.生产出的飞轮壳体铸件,石墨分布较均匀,基体组织为珠光体加铁素体,抗拉强度达200 MPa以上.%The article systematically interpreted the process and parameter of lost foam casting,taking gray cast iron flywheel cover for example.Step gating system and raining wise sand filling was adopted.The gating ratio was F内: F横: F直 = 1.0: 1.2: 1.4.The negative pressure was 0.04 ~0.055 MPa during pouring.And the pouring temperature was controlled at 1 470~ 1 480 ℃.With uniformly distributed graphite, matrix of the flywheel cover casting was pearlite and ferrite.Its tensile strength was higher than 200 MPa.

  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. Potencial produtivo de videiras cultivadas sob cobertura de plástico Yield potential of grapevine cultivated under plastic cover

    Directory of Open Access Journals (Sweden)

    Geraldo Chavarria

    2009-02-01

    Full Text Available O objetivo deste trabalho foi avaliar a influência do uso de cobertura de plástico sobre os componentes do rendimento da videira (Vitis vinifera L. cultivar Moscato Giallo. O experimento foi realizado nas safras 2005/2006 e 2006/2007, em Flores da Cunha, RS, em duas áreas de vinhedo, uma com cobertura de plástico impermeável e outra sem cobertura (controle. O microclima foi avaliado quanto à temperatura e umidade relativa do ar, radiação fotossinteticamente ativa e velocidade do vento próximo ao dossel vegetativo e a os cachos. A avaliação dos componentes de rendimento ocorreu em delineamento experimental inteiramente ao acaso, e foram identificadas dez plantas marcadas aleatoriamente em cada área. Avaliaram-se a produção por planta e por hectare, o número de cachos por planta e por metro quadrado, o número de sarmentos por metro quadrado, a massa e comprimento de cacho, a massa de engaço, o número de bagas por cacho, o diâmetro transversal de bagas e a relação entre massa de película e massa de polpa. Acobertura de plástico possibilita aumento na produtividade, não afeta a relação entre massa de casca e massa de polpa das bagas e favorece a estabilidade de produção, independentemente das condições meteorológicas no ciclo.The objective of this work was to evaluate the effect of plastic cover on the yield components of grapevine (Vitis vinifera L. cultivar Moscato Giallo. The experiment was carried out in 2005/2006 and 2006/2007 crop seasons, in Flores da Cunha, RS, Brazil, in two vineyard areas, one covered with an impermeable plastic film and other without covering (control. The microclimate was evaluated in terms of air temperature, air relative humidity, photosynthetically active radiation and wind speed above canopy and close to clusters. The yield components were evaluated in a completely randomized design, in ten plants randomly selected in each area. Measures were made for production per plant, yield per

  1. F-15B in on ramp with close-up of test panels covered with advanced spray-on foam insulation materia

    Science.gov (United States)

    1999-01-01

    Test panels covered with an advanced foam insulation material for the Space Shuttle's giant external fuel tank were test flown aboard an F-15B research aircraft at NASA's Dryden Flight Research Center, Edwards, Calif. Six panels were mounted on the left side of a heavily instrumented Flight Text Fixture mounted underneath the F-15B's fuselage. Insulation on this panel was finely machined over a horizontal rib structure to simulate in-line airflow past the tank; other panels had the ribs mounted vertically or had the insulation left in a rough as-sprayed surface. The tests were part of an effort by NASA's Marshall Space Flight Center to determine why small particles of the new insulation flaked off the tank on recent Shuttle missions. The tests with Dryden's F-15B were designed to replicate the pressure environment the Shuttle encounters during the first minute after launch. No noticeable erosion of the insulation material was noted after the flight experiment at Dryden.

  2. 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...

  3. 塑料水杯盖注塑模具设计%Development of Injection Mold for Plastic Cup Cover

    Institute of Scientific and Technical Information of China (English)

    李润娟; 张艳霞

    2014-01-01

    The 3D shape of the plastic cup cover is generated by the software UG.Based on the analysis of the structure process of the plastic parts, The gate location and the mould joint are selected,the core and cavity of the mould structure are designed.A large number of computer aided design is used in the course of design, which shorts the development cycle and reduces production cost.%利用UG软件对塑料水杯盖进行了产品的三维造型,在对塑件结构工艺性分析的基础上,进行了浇口位置和分型面的选择,型芯、型腔、模具等结构的设计,设计过程中采用了大量计算机辅助模具设计,缩短了开发周期,降低了生产成本。

  4. Influence of Covering Reused Broiler Litter with Plastic Canvas on Litter Characteristics and Bacteriology and the Subsequent Immunity and Microbiology of Broilers

    Directory of Open Access Journals (Sweden)

    D Mesa

    Full Text Available ABSTRACT In broiler production, the litter is reused for consecutives flocks, and it is treated during down time between flocks to reduce its microbial load. Although covering the litter with a plastic canvas is a common litter treatment in the field, there is little scientific information available on its efficacy. The aim of this study was to evaluate the effects of covering broiler litter with a plastic canvas for eight days on litter microbiological, physical, and chemical parameters, and on the intestinal microbiota and immunity of broilers. In the first trial, reused litter from a previous flock was distributed into three treatments, with six replicates each: L1 (negative control, litter free from Salmonella Enteritidis (SE and Eimeria maxima (EM and not covered, L2 (positive control, litter with SE and EM, and not covered, and L3 (litter with SE and EM, and covered with plastic canvas for eight days. Litter total bacteria, Enterobacteria, Lactobacillus, SE, and EM counts, and litter pH, temperature, moisture, and ammonia emission were determined on days 1 and 8. In the second trial, broilers were housed on those litters according to the treatments described above, and their intestinal microbiota, gut CD4+ and CD8+ lymphocytes and macrophages, and liver and intestinal pro-inflammatory interleukin (IFN-γ, IL-1β e IL-18 levels were evaluated on days 14 and 28. A significant reduction of litter bacterial populations was observed in the litter covered with plastic canvas. A significantly higher mRNA IFN-γ gene expression (12.5-fold was observed in the jejunum and liver of broilers reared on the litter with Enterobacteria counts. No EM reduction was observed in the covered litter. Covering reused broiler litter with plastic canvas reduces initial litter bacterial load as a result of the interaction between physical and chemical parameters.

  5. Thermo-mechanical response of rigid plastic laminates for greenhouse covering

    Directory of Open Access Journals (Sweden)

    Silvana Fuina

    2016-09-01

    Full Text Available Innovation in the field of protected crops represents an argument of great applied and theoretical research attention due to constantly evolving technologies and automation for higher quality flower and vegetable production and to the corresponding environmental and economic impact. The aim of this paper is to provide an analysis of some thermomechanical properties of rigid polymeric laminates for greenhouses claddings, including innovative tests such as the thermographic ones. Four types of laminates have been analysed: two polycarbonates, a polymethylmethacrylate and a polyethylene terephthalate (PET. The tests gave interesting results on different important properties, such as radiometric properties, limit stresses, strains and ductility. Moreover, a direct comparison of infrared images and force elongation curves gave important information on the relation of the (localised or homogeneous damage evolution, with both an applicative and theoretical implication. Finally, even if to the authors knowledge at present there are no examples of using PET for covering greenhouses, the results of this paper indicates the thermomechanical and radiometric characteristics of this material make it interesting for agricultural applications.

  6. Performance Analysis of a Fiber Reinforced Plastic Oil Cooler Cover Considering the Anisotropic Behavior of the Fiber Reinforced PA66

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2016-09-01

    Full Text Available In this paper, a simulation method based on an orthogonal anisotropic material is proposed. A numerical example using a simple plate is presented to show the difference in the static performance between the orthogonal anisotropic and the isotropic models. Comparing with the tested modal data of a diesel engine oil cooler cover made by glass fiber reinforced polyamide 66 (PA66, the proposed simulation method was confirmed to be much closer to reality than the general isotropic model. After that, a comprehensive performance comparison between the plastic oil cooler covers with the orthogonal anisotropic and the isotropic fiber orientations was carried out including a static deformation and stress analysis under a pressure-temperature coupled load, a forced response analysis, and an acoustic analysis under real operating conditions. The results show that the stress, the deformation, the peak vibration velocity, and the overall sound power level of the orthogonal anisotropic model are different from that obtained with the isotropic model. More importantly, the proposed method can provide a much more detailed frequency content compared to the isotropic model.

  7. Cover Plastic Planting Technology of Spring Virus-free Potato%春季脱毒马铃薯地膜覆盖栽培技术

    Institute of Scientific and Technical Information of China (English)

    张金龙

    2012-01-01

    The paper introduced cover plastic planting technology of spring virus-free potato,such as plowing soil deeply,cutting into parts and sprouting,cover plastic cultivation,fertilizing basic fertilizer,field management,pest control and so on,in order to provide a reference.%介绍春季脱毒马铃薯地膜覆盖栽培技术,包括土壤深翻、切块催芽、覆膜栽培、施基肥、田间管理、病虫害防治等方面内容,以供参考。

  8. 聚氨酯泡沫塑料填料的改性试验研究%Experimental Study on Modification of Polyurethane Foam Plastics Carriers

    Institute of Scientific and Technical Information of China (English)

    成国栋; 王芬; 李超; 汪泳; 赵贞地; 季民

    2012-01-01

    The conventional polyurethane foam plastic carrier was modified by chemical oxidation and gelatin protein grafting technology, and the surface physicochemical properties of the carrier, the speed of biofilm formation, the quantity of biofilm and the performance in treating wastewater were investigated before and after the modification. The results showed that the ratio of C - 0 bond on surface of the modified carrier was increased by 47. 86% , and the ratios of C - C and C - H bonds on surface of the modified carrier were reduced by 50. 66%. Hydrophilicity and surface roughness of the carrier were increased after the modification. Compared with the original carrier, the quantity of biofilm on the modified carrier was increased by 30% , the average growth rate of biofilm was increased by 47% , and the removal rates of COD and ammonia nitrogen were increased.%采用化学氧化-明胶蛋白接枝技术对普通聚氨酯泡沫塑料填料进行改性,并对改性前后填料的表面特性、挂膜速度、生物膜量及除污性能等进行研究.结果发现,改性填料表面的C-O键所占比例提高了47.86%,C-C、C-H键所占比例下降了50.66%;改性填料的表面粗糙度以及亲水性提高;与未改性填料相比,改性填料的生物膜量提高了30%,生物膜量的平均增长速率提高了47%;与未改性填料相比,改性填料对COD和氨氮的去除率均有所提高.

  9. EVAC对PE基木塑微发泡复合材料性能影响的研究%INFLUENCE OF EVAC ON PROPERTIES OF PE BASED WOOD PLASTIC MICRO-FOAMED COMPOSITE

    Institute of Scientific and Technical Information of China (English)

    蔡建臣; 薛平; 祁宗; 丁筠; 金晓明

    2011-01-01

    PE based wood plastic micro-foamed composite was prepared with EVAC as modifier by a conical twin screw extruder. The effect of different EVAC content on the mechanical properties were studied, combined wtth SEM observation of cross-section morphology of composite materials. The results showed that the tensile strength, bending strength and impact strength of the PE based wood plastic micro-foamed composite increased with the increase of EVAC content. EVAC can improve the interfacial compatibilization between the wood flour and polymer, the optimum dosage of EVAC was 12.5% of wood flour content. In addition, this paper discussed the role of EVAC in the micro-foamed process of PE based wood plastic composite.%使用乙烯-乙酸乙烯酯塑料(EVAC)作为改性剂,通过锥形双螺杆成型机制备了聚乙烯(PE)基木塑微发泡复合材料.研究了EVAC用量对复合材料力学性能的影响,并且运用扫描电子显微镜观察了复合材料断面的微观形貌.结果表明,PE基木塑微发泡复合材料的拉伸强度、弯曲强度、冲击强度均随FVAC用量的增加而增大,EVAC可以提高PE/木粉界面之间的相容性,其最佳用量为木粉含量的12.5%.探讨了EVAC在PE基木塑微发泡复合材料微发泡过程中所起的作用.

  10. Research on Properties of Rigid Polyurethane Foam Plastics Modiifed by Composite Flame Retardant%复合阻燃剂阻燃硬质聚氨酯泡沫塑料的性能研究

    Institute of Scientific and Technical Information of China (English)

    张忠厚; 王银涛; 杨光; 冯丽; 闫春绵

    2014-01-01

    Rigid polyurethane(PUR-R) foam plastics modified by composite flame retardant were prepared. Effects of composite flame retardant dimethyl methylphosphonate(DMMP),trichloropropylphosphate(TCPP),expandable graphite(EG) and aluminum hydroxide(ATH) on the properties of PUR-R foam plastics modified by composite flame retardant were studied. The optimum proportion of the composite flame retardant was determined with orthogonal experiment. The limited oxygen index(LOI), the smoke density rating and the compressive strength were obtained by LOI instrument,smoke density determinator and material testing machine. The results show that when the mass ratio of DMMP,TCPP,EG,ATH are 2∶2∶3∶3,12 phr composite flame retardant is added to 25 phr polyether polyols,the LOI,the smoke density rating and the compressive strength of PUR-R foam plastics modified by composite flame retardant are 26.3%,77.63 and 0.18 MPa respectively,PUR-R foam plastics modified by composite flame retardant have better comprehensive properties .%制备了复合阻燃剂阻燃硬质聚氨酯(PUR-R)泡沫塑料,研究了复合阻燃剂甲基膦酸二甲酯(DMMP)、三(2-氯异丙基)磷酸酯(TCPP)、可膨胀型石墨(EG)和氢氧化铝(ATH)对PUR-R泡沫塑料阻燃性能的影响,采用正交试验确定了复合阻燃剂的最佳配比。用极限氧指数(LOI)测定仪、烟密度测定仪和万能试验机测定了阻燃PUR-R泡沫塑料的LOI、烟密度等级和压缩强度,结果表明,当DMMP,TCPP,EG,ATH的质量比为2∶2∶3∶3时,在25份聚醚多元醇中添加12份复合阻燃剂,制备的阻燃PUR-R泡沫塑料的LOI达26.3%,烟密度等级为77.63,压缩强度为0.18 MPa,阻燃PUR-R泡沫塑料具有良好的综合性能。

  11. 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.

  12. 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.

  13. 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.

  14. Numerical Simulation on Lost Foam Casting of Gray Cast Iron Box Cover%灰铸铁箱盖的消失模铸造数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    李建军; 杜晓明

    2013-01-01

    The lost foam casting process of gray cast iron box cover was simulated by using the numerical simulation method. The properties of the mould filling and solidification for lost foam casting were studied. And the comparison of the simulated results with the practical casting was carried out. The results show that the bottom gating system is used for the casting, pouring temperature is 1400℃, foam density is 13 kg/m3, vacuum is 0.04 MPa, coating thickness is 0.5 mm and coating permeability is 9.5×l0-9m/(Pa·s).%采用数值模拟方法对灰铸铁箱盖的消失模铸造过程进行了模拟.研究了消失模铸造的充填与凝固特性,并与实际生产进行了对比.结果表明,该件采用底注式浇注系统,浇注温度为1400℃,泡沫模样密度为13 kg/m3,负压度为0.04MPa,涂料厚度为0.5mm,涂料透气性为9.5× 10-9m2/(pa.s).

  15. 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...

  16. The Effect of Plastic-Covered Ridge and Furrow Planting on the Grain Filling and Hormonal Changes of Winter Wheat

    Institute of Scientific and Technical Information of China (English)

    LIU Yang; HAN Juan; WEN Xiao-xia; WU Wei; GUO Qiang; ZENG Ai; LIAO Yun-cheng

    2013-01-01

    Although plastic-covered ridge and furrow planting (RF) has been reported to produce substantial increases in the grain weight of winter wheat, the underlying mechanism is not yet understood. The present study used two cultivars, Xinong 538 and Zhoumai 18, and RF and traditional lfatten planting (TF, control) with the objective of investigating the effect of RF on wheat grain iflling and the possible relationship of hormonal changes in the wheat grains under RF to grain iflling. The results indicated that RF signiifcantly increased the grain weight, although the effects on grain iflling were different: RF signiifcantly increased the grain-iflling rate and grain weight of inferior grains, whereas RF had no signiifcant effect on grain-iflling rate and grain weight of superior grains. The ifnal grain weight of inferior grains under RF was 39.1 and 50.7 mg for Xinong 538 and Zhoumai 18, respectively, 3.6 and 3.4 mg higher than the values under TF. However, the ifnal grain weight of superior grains under RF was only 0.6 and 0.8 mg higher than under TF for Xinong 538 and Zhoumai 18, respectively. RF signiifcantly decreased the ethylene and gibberellic acid content in the inferior grains and increased the indole-3-acetic acid, abscisic acid and zeatin+zeatin riboside content in the inferior grains; however, no signiifcant difference between RF and TF was observed for the hormonal content in the superior grains. Based on these results, we concluded that RF signiifcantly modulated hormonal changes in the inferior grains and, thus, affected the grain iflling and grain weight of the inferior grains;in contrast, RF had no signiifcant effect on grain iflling, grain weight and hormonal changes in the superior wheat grains.

  17. Preparation of Grapheme Oxide and Grapheme Oxide Based Phenolic Foam Plastics%氧化石墨烯的制备及其改性酚醛泡沫塑料

    Institute of Scientific and Technical Information of China (English)

    方红霞; 吴强林; 吴沁然; 潘乐; 冯晓云; 韩信

    2013-01-01

    以改进的Hummers法为基础,重点探究了高温阶段不同的保温时间与保温温度对氧化石墨烯活性的影响,并通过傅立叶变换红外光谱和X射线衍射对氧化后的石墨烯进行结构分析。结果表明,当高温阶段的保温时间为20 min,保温温度为80℃或85℃时,氧化石墨烯(GO)的氧化程度最高,采用改进的Hummers法获得的GO具有较高活性和更为规整的结晶结构。采用原位发泡制备了酚醛树脂/GO泡沫塑料。结果表明,GO的加入能有效地提高泡沫塑料的耐热性能、阻燃性能,并改善其防水性能。%Based on a modiifed Hummers method,the effects of different holding time and different holding temperature at the high-temperature stage on the properties of graphene oxide(GO) were studied. The results show that when holding time and holding temperature are 20 min and 80℃or 85℃at the high temperature stage, the oxidation degeree of GO is highest. FTIR and XRD analyses show that GO approached by the modiifed Hummers method has higher activity and crystallinity as well. Compared with the traditional phenolic foam plastic,the PF/GO foam plastic prepared by in situ foaming has better mechanical properties,thermal properties and waterproof performance.

  18. Comparison of surface emissions and subsurface distribution of cis- and trans-1,3-dichloropropene and chloropicrin in sandy field beds covered with four different plastic films.

    Science.gov (United States)

    Ou, Li-Tse; Thomas, John E; Allen, L Hartwell; Vu, Joseph C; Dickson, Donald W

    2008-06-01

    The purpose of this study was to conduct a field study at a Florida field site on surface emissions and subsurface distribution of cis-and trans-1,3-dichloropropene (1,3-D) and chloropicrin (CP) in raised beds injected with Telone C35 with four replications. A total of 16 beds were applied with Telone C35 by chisel injection and covered with four different plastic films, 4 beds for each film. Each bed was installed with five 20-cm long soil pore air probes and a surface air collection pan at arbitrarily locations along the length of each bed for sampling soil pore air and surface air, respectively, for analysis of the three biologically active compounds, cis- and trans-1,3-D and CP. We found that average concentrations of the three compounds at 20-cm depth among the beds covered with four different plastic films generally were not statistically different. Among the four beds covered with the same plastic film, average concentrations of the three compounds were statistically different only in the four metallic PE covered beds at 5 and 24 hours after injection. Volatilization rates of the three compounds among the beds covered with four different plastic films, with the exception of CP at 48 hours after injection, were not statistically different. It appeared that initial upward diffusion and volatilization flux were influenced by solar radiation. Initial subsurface concentrations of the three compounds and volatilization flux, especially cis-1,3-D, were greater in the beds on the east side of the field than that in the beds on the west side of the field. Whether or not difference in initial subsurface concentrations of the compounds between east side beds and west side beds may influence fumigant efficacy remains to be determined.

  19. Plasticity theory

    CERN Document Server

    Lubliner, Jacob

    2008-01-01

    The aim of Plasticity Theory is to provide a comprehensive introduction to the contemporary state of knowledge in basic plasticity theory and to its applications. It treats several areas not commonly found between the covers of a single book: the physics of plasticity, constitutive theory, dynamic plasticity, large-deformation plasticity, and numerical methods, in addition to a representative survey of problems treated by classical methods, such as elastic-plastic problems, plane plastic flow, and limit analysis; the problem discussed come from areas of interest to mechanical, structural, and

  20. 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

  1. 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.

  2. 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.

  3. Alterações micrometeorológicas em vinhedos pelo uso de coberturas de plástico Micrometeorological alterations in vineyards by using plastic covering

    Directory of Open Access Journals (Sweden)

    Loana Silveira Cardoso

    2008-04-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos da cobertura de plástico sobre alguns elementos meteorológicos que formam o microclima de vinhedos de Vitis vinifera L., cultivar Moscato Giallo, em Flores da Cunha, na Serra Gaúcha. O experimento foi conduzido na safra 2005/2006, com os tratamentos: fileiras de plantas descobertas; e fileiras de plantas cobertas com plástico transparente tipo ráfia, com 160 µm de espessura. Medições contínuas de radiação fotossinteticamente ativa, temperatura e umidade do ar, e velocidade do vento foram realizadas: acima da cobertura; entre a cobertura e o dossel; sobre o dossel descoberto; e junto aos cachos de ambos tratamentos. Estimou-se a evapotranspiração de referência nos dois tratamentos. Da radiação fotossinteticamente ativa incidente, 67,5% chegou ao dossel coberto, 16% atingiu os cachos cobertos e 36% chegou aos cachos descobertos. A cobertura aumentou em 3,4ºC as temperaturas máximas do ar junto às plantas. A umidade relativa do ar diurna foi menor, enquanto a pressão de vapor e o deficit de saturação foram superiores debaixo da cobertura. A velocidade do vento foi reduzida pela cobertura em 88%. No ambiente coberto, a evapotranspiração de referência foi 65% daquela do ambiente externo. Embora aumente as temperaturas diurnas, a cobertura de plástico promoveu redução na demanda evaporativa do vinhedo.The objective of this work was to evaluate the effects of plastic covering on the microclimate of vineyards (Vitis vinifera L., cultivar Moscato Giallo, in Serra Gaúcha region in Rio Grande do Sul State, Brazil. The experiment was performed in Flores da Cunha, RS, during the 2005/2006 growing season. It comprised uncovered and covered rows of vines, using a 160 µm thick plastic film. Photossinthetically active radiation (PAR, air temperature and humidity, and wind velocity were monitored: over the plastic covering; between the film and the canopy; over the uncovered canopy

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  8. Comportamento vegetativo e produtivo de videiras 'Cabernet sauvignon' cultivadas sob cobertura plástica Vegetative growth and yield of 'Cabernet sauvignon' grapevine under overhead plastic covering

    Directory of Open Access Journals (Sweden)

    Clenilso Sehnen Mota

    2008-03-01

    Full Text Available O uso de cobertura plástica no cultivo de videira encontra-se em expansão no Rio Grande do Sul, por ser uma alternativa que visa a proteger as plantas da precipitação pluvial e do granizo. O objetivo deste estudo foi avaliar os impactos de uma cobertura plástica translúcida e impermeável sobre a fenologia, o crescimento (de ramos, folhas, cachos e bagas e a produtividade em videiras 'Cabernet Sauvignon' (Vitis vinifera L., com cinco anos de idade, conduzidas em sistema 'Y', sobre porta-enxerto Paulsen 1103. O experimento, conduzido no município de Caxias do Sul-RS, seguiu o delineamento em blocos ao acaso, tendo os tratamentos sem e com cobertura plástica, com quatro repetições de 15 plantas (unidade experimental. As alterações microclimáticas impostas pela cobertura plástica não foram expressivas para alterar a fenologia da videira. As plantas cultivadas sob cobertura plástica apresentaram maiores valores de comprimento e massa fresca de ramos e de área, e massa seca foliar em comparação às plantas descobertas. O peso e o diâmetro de bagas foram superiores nas videiras cobertas apenas no início do ciclo e não diferiram próximo da colheita. As demais variáveis analisadas não foram afetadas pela cobertura plástica. A cobertura plástica interferiu no crescimento vegetativo das plantas, mas não afetou a produção.There is an increasing adoption of overhead plastic covering for grapevines in the State of Rio Grande do Sul, Southern Brazil, to protect the plants from rain and hail storms. This study was carried out to evaluate the impacts of overhead plastic covering with a translucent and water-proof plastic film on phenological, growth (of branch, leaves, clusters, and berries, and yield attributes of five years old 'Cabernet Sauvignon' grapevines (Vitis vinifera L. on Paulsen 1103 rootstock raised as 'Y' management system. The experiment was carried out in Caxias do Sul, State of Rio Grande do Sul, and followed a

  9. Emissions and distribution of methyl bromide in field beds applied at two rates and covered with two types of plastic mulches.

    Science.gov (United States)

    Ou, Li-Tse; Thomas, John E; Allen, L Hartwell; Vu, Joseph C; Dickson, Donald W

    2007-01-01

    A field experiment was conducted to compare two plastic mulches and two application rates on surface emissions and subsurface distribution of methyl bromide (MBr) in field beds in Florida. Within 30 minutes after injection of MBr to 30 cm depth, MBr had diffused upward to soil surface in all beds covered with polyethylene film (PE) or virtually impermeable film (VIF) and applied at a high rate (392 kg/ha) and a low rate (196 kg/ha). Due to the highly permeable nature of PE, within 30 minutes after injection, MBr volatilized from the bed surfaces of the two PE-covered beds into the atmosphere. The amount of volatilization was greater for the high rate-treatment bed. On the other hand, volatilization of MBr from the bed surfaces of the two VIF-covered beds were negligible. Volatilization losses occurred from the edges of all the beds covered with PE or VIF and were greater from the high rate-treatment beds. Initial vertical diffusion of MBr in the subsurface of the beds covered with PE or VIF was mainly upward, as large concentrations of MBr were detected from near bed surfaces to 20 cm depth in these beds 30 minutes after injection and little or no MBr was found at 40 cm depth. The two VIF-covered beds exhibited greater MBr concentrations and longer resident times in the root zone (0.5-40 cm depth) than corresponding PE-covered beds. Concentrations of MBr in the root zone of the high rate-treatment beds were 3.6-6.1 times larger than the low rate-treatment beds during the first days after application. In conclusion, VIF promoted retention of MBr in the root zone and, if volatilization loss from bed edges can be blocked, volatilization loss from VIF-covered beds should be negligible.

  10. Design of Plastic Injection Mold for the New Switch Cover%新型开关盖注射模设计

    Institute of Scientific and Technical Information of China (English)

    洪晓燕

    2012-01-01

    This paper described design steps of injection mold of a new switch cover, including plastic process analysis, determine of molding project, choice of injection machine, the overall structure design of the mold, molding size calculations and so on.%阐述了新型开关盖注射模的设计步骤,主要包括塑件工艺性分析、成型方案的确定、注塑机的选择与校核、模具的总体结构设计、成型尺寸的计算等方面。

  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. 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...

  14. Persistence, distribution, and emission of Telone C35 injected into a Florida sandy soil as affected by moisture, organic matter, and plastic film cover.

    Science.gov (United States)

    Thomas, J E; Ou, L T; Allen, L H; McCormack, L A; Vu, J C; Dickson, D W

    2004-05-01

    With the phase-out of methyl bromide scheduled for 2005, alternative fumigants are being sought. This study of Telone C35, a mixture of (Z)- and (E)-1,3-dichloropropene (1,3-D) with chloropicirin (CP), focuses on its emissions, distribution, and persistence in Florida sandy soil in microplots with different soil-water and organic matter carbon (C) content with and without two different plastic film mulches. The addition of CP did not affect the physical behavior of the isomers of 1,3-D. Slower subsurface dispersion and longer residence time of the mixed fumigant occurred at higher water content. An increase in the percent organic carbon in the soil led to a more rapid decrease for chloropicirin than for 1,3-dichloropene isomers. The use of a virtually impermeable film (VIF) for soil cover provided a more even distribution and longer persistence under all the conditions studied in comparison to polyethylene (PE) film cover or no cover. The conditions of near field capacity water content, low organic matter, and a virtually impermeable film cover yielded optimum conditions for the distribution, emission control, and persistence of Telone C35 in a Florida sandy soil.

  15. 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.

  16. Injection Mould Design Delphi Plastic End Cover%小议塑料端盖注射模设计

    Institute of Scientific and Technical Information of China (English)

    王琳

    2015-01-01

    The design detail of a plastic mold, molding characteristics from product and process analysis, to determine the performance of injection molding materials and sub-surface selection and gating system, injection machine selection and verification, side parting aspects of the work and molded parts, such as the size of the calculation are described.%详细地介绍了一个塑料制品成型模具,从制品的成型特点和工艺性分析、注射材料的成型性能和分型面的选择和浇注系统的确定、注射机的选择和校核、侧面分型以及成型零件工作尺寸的计算等方面进行了说明。

  17. Bone Regeneration after Treatment with Covering Materials Composed of Flax Fibers and Biodegradable Plastics: A Histological Study in Rats.

    Science.gov (United States)

    Gredes, Tomasz; Kunath, Franziska; Gedrange, Tomasz; Kunert-Keil, Christiane

    2016-01-01

    The aim of this study was to examine the osteogenic potential of new flax covering materials. Bone defects were created on the skull of forty rats. Materials of pure PLA and PCL and their composites with flax fibers, genetically modified producing PHB (PLA-transgen, PCL-transgen) and unmodified (PLA-wt, PCL-wt), were inserted. The skulls were harvested after four weeks and subjected to histological examination. The percentage of bone regeneration by using PLA was less pronounced than after usage of pure PCL in comparison with controls. After treatment with PCL-transgen, a large amount of new formed bone could be found. In contrast, PCL-wt decreased significantly the bone regeneration, compared to the other tested groups. The bone covers made of pure PLA had substantially less influence on bone regeneration and the bone healing proceeded with a lot of connective tissue, whereas PLA-transgen and PLA-wt showed nearly comparable amount of new formed bone. Regarding the histological data, the hypothesis could be proposed that PCL and its composites have contributed to a higher quantity of the regenerated bone, compared to PLA. The histological studies showed comparable bone regeneration processes after treatment with tested covering materials, as well as in the untreated bone lesions.

  18. Bone Regeneration after Treatment with Covering Materials Composed of Flax Fibers and Biodegradable Plastics: A Histological Study in Rats

    Science.gov (United States)

    Gedrange, Tomasz

    2016-01-01

    The aim of this study was to examine the osteogenic potential of new flax covering materials. Bone defects were created on the skull of forty rats. Materials of pure PLA and PCL and their composites with flax fibers, genetically modified producing PHB (PLA-transgen, PCL-transgen) and unmodified (PLA-wt, PCL-wt), were inserted. The skulls were harvested after four weeks and subjected to histological examination. The percentage of bone regeneration by using PLA was less pronounced than after usage of pure PCL in comparison with controls. After treatment with PCL-transgen, a large amount of new formed bone could be found. In contrast, PCL-wt decreased significantly the bone regeneration, compared to the other tested groups. The bone covers made of pure PLA had substantially less influence on bone regeneration and the bone healing proceeded with a lot of connective tissue, whereas PLA-transgen and PLA-wt showed nearly comparable amount of new formed bone. Regarding the histological data, the hypothesis could be proposed that PCL and its composites have contributed to a higher quantity of the regenerated bone, compared to PLA. The histological studies showed comparable bone regeneration processes after treatment with tested covering materials, as well as in the untreated bone lesions. PMID:27597965

  19. 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.

  20. Evolution of shock through a void in foam

    Science.gov (United States)

    Kim, Y.; Smidt, J. M.; Murphy, T. J.; Douglass, M. R.; Devolder, B. G.; Fincke, J. R.; Schmidt, D. W.; Cardenas, T.; Newman, S. G.; Hamilton, C. E.; Sedillo, T. J.; Los Alamos, NM 87544 Team

    2016-10-01

    Marble implosion is an experimental campaign intended to study the effects of heterogeneous mix on fusion burn. A spherical capsule is composed of deuterated plastic foam of controlled pore (or void) size with tritium fill in pores. As capsule implosion evolves, the initially separated deuterium and tritium will mix, producing DT yields. Void evolution during implosion is of interest for the Marble campaign. A shock tube, driven by the laser at Omega, was designed to study the evolution of a shock through a foam-filled ``void'' and subsequent void evolution. Targets were comprised of a 100 mg/cc CH foam tube containing a 200-µm diameter, lower density doped foam sphere. High-quality, radiographic images were obtained from both 2% iodine-doped in plastic foam and 15% tin-doped in aerogel foam. These experiments will be used to inform simulations.

  1. Foamed plastics in buried pipes. PE tubes - unsuitable for heat pumps?; Wenn's im Erdreich schaeumt.... PE-Sonden fuer Waermepumpen ungeeignet?

    Energy Technology Data Exchange (ETDEWEB)

    Ameling, Werner [Fachhochschule Trier (Germany). Technische Gebaeudeausruestung; Omnium Technic (Germany)

    2009-06-15

    The gas permeability of plastic tubes has become a matter of discussion. The focus is currently on PE tubes of soil-to-water heat pumps. If a heat pump system with vertical probes is switched on again after a longer period of standstill, start-up problems may ensue especially in regions with underground CO2 sources or CO2 stores. (orig.)

  2. Evaluation of retail fresh meat packagings covered with stretch films of plasticized PVC and non-PVC alternatives

    DEFF Research Database (Denmark)

    Petersen, Jens Højslev; Togeskov, P.; Hallas, J.

    2004-01-01

    The characteristics and performance of several non-PVC stretch films were compared to those of plasticized PVC. Initially the main polymer components Of the film were identified by infrared spectrometry and differential scanning calorimetry. The differences between films in mechanical properties,...... (thiobarbituric acid reactive substances) through a prolonged shelf-life test. No differences in meat quality during normal shelf-life were seen as a function of the film used....... to legislation. The potential for specific migration was investigated by solvent extraction followed by gas chromatography. Twenty-four components were identified, of which 11 could be compared to relevant migration limits based on evaluations of the EU Scientific Committee for Food. The release of solvents...... was estimated by direct thermal desorption at 100degreesC. Four films of different composition were used in a storage experiment with fresh beef. The meat quality was followed by measurements of colour, microbiological quality (total colony forming units and lactic acid bacteria) and lipid oxidation...

  3. 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.

  4. 不同种类木纤维对PE基微孔发泡木塑复合材料的性能影响%The Influence of Different Kinds of Wood Fiber on the Properties of PE based Microcellular Foaming Wood and Plastic Composite

    Institute of Scientific and Technical Information of China (English)

    葛正浩; 石美浓; 陈伟博; 杜晓龙

    2012-01-01

    PE base microporous foam wood fiber/plastic composite was prepared by extrusion, injection molding process. Density , bending strength, tensile strength and impact strength of the PE base microporous foam wood fiber/plastic were researched from different types of wood fiber. The experiment results showed that wood flour filler made of wood-plastic micropore foam composite density was best,the impact strength of bamboo and straw powder were superior to wood powder,and bamboo powder composites had produced the best mechanical properties.%采用挤出、注塑成型工艺制备PE基木纤维/塑料微孔发泡复合材料.从不同木纤维的种类对PE基木纤维/塑料微孔发泡复合材料的密度、冲击强度、弯曲强度、拉伸强度进行研究.实验结果表明:以木粉为填料所制得的木塑微孔发泡复合材料密度最佳;竹粉和秸秆粉的冲击强度都优于木粉,且竹粉所制得的复合材料具有最佳的力学性能.

  5. Ultrasonic Measurement of Elastic Modulus of Kelvin Foam

    Directory of Open Access Journals (Sweden)

    Oh Sukwon

    2016-01-01

    Full Text Available Elastic modulus of 3D-printed Kelvin foam plate is investigated by measuring the acoustic wave velocity of 1 MHz ultrasound. An isotropic tetrakaidecahedron foam of 3 mm unit cell is designed and printed layer upon layer to fablicate a Kelvin foam plate of 14mm thickness by 3D CAD/printer using ABS plastic. The Kelvin foam plate is filled completely with paraffin wax for impedance matching, so that acoustic wave may propagate through the porous foam plate. The acoustic wave velocity of the foam plate is measured using the time-of-flight (TOF method to calculate the elastic modulus of the Kelvin foam plate based on acousto-elasticity.

  6. 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.

  7. 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.

  8. Thermal, chemical, and mechanical response of rigid polyurethane foam

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, M.L.

    1997-12-01

    Rigid polyurethane foams are frequently 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. Mechanical response of the decomposing foam, such as thermal expansion under various loading conditions created by gas generation, remains a major unsolved problem. A constitutive model of the reactive foam is needed to describe the coupling between mechanical response and chemical decomposition of foam exposed to environments such as fire. Towards this end, a reactive elastic-plastic constitutive model based on bubble mechanics describing nucleation, decomposition chemistry, and elastic/plastic mechanical behavior of rigid polyurethane foam has been developed. A local force balance, with mass continuity constraints, forms the basis of the constitutive model requiring input of temperature and the fraction of the material converted to gas. This constitutive model provides a stress-strain relationship which is applicable for a broad class of reacting materials such as explosives, propellants, pyrotechnics, and decomposing foams. The model is applied to a block of foam exposed to various thermal fluxes. The model is also applied to a sphere of foam confined in brass. The predicted mechanical deformation of the foam block and sphere are shown to qualitatively agree with experimental observations.

  9. APPLICATION OF POLYETHYLENE FOAM PLASTIC SHEET IN WATERPROOF PROTECTION LAYER%聚乙烯泡沫塑料片材在防水保护层中的应用

    Institute of Scientific and Technical Information of China (English)

    吕文良

    2011-01-01

    新型聚乙烯泡沫塑料片材防水保护层区别于传统材料,既可满足图集和施工要求,又可大大降低成本.在某工程地下室防水保护层施工中采用了横向粘贴方法,并与其他保护层进行技术经济对比分析,提出了实践过程中需探讨的几个问题.%The waterproof protection layer made of new polyethylene foam plastic sheet is different from traditional material. It can not only satisfy the drawing collection and construction requirements, but also reduce the cost greatly. During the construction of basement waterproof layer in this engineering, transverse sticking method is adopted, technical and economic comparison and analysis are made with other protective layer. Finally, several problems which shall be discussed in practice are put forward.

  10. Uso de cubiertas plásticas para solarización de estiércol bovino Use of plastic covers for solarization cattle manure

    Directory of Open Access Journals (Sweden)

    Cirilo Vázquez Vázquez

    Full Text Available El presente trabajo se realizó con la finalidad de evaluar cubiertas plásticas, para emplearlas en la solarización de estiércol bovino, como un método activo que pueda lograr la inactivación de patógenos, para obtener un residuo orgánico e inocuo. En los meses de junio y julio de 2004, se compararon tratamientos de pilas de estiércol cubiertas con plástico transparente sin albedo de 100 µm de grosor, una con cubierta sencilla, otra con cubierta doble y un testigo sin cubrir. Se tomaron muestras del estiércol solarizado y sin solarizar, para realizar la siembra en medios de cultivo de papa-dextrosa-agar, para detectar hongos coprofilos así como para detectar Escherichia coli y Salmonella spp. Los resultados mostraron mayor homogeneidad de temperatura en la pila con doble cubierta en el plano vertical, con 62 ºC a 30 cm de profundidad y 60 ºC a 90 cm, la cubierta sencilla alcanzó una temperatura de 61.5 ºC en el estrato superior y 58 ºC a 90 cm de profundidad, el testigo mostró mayor heterogeneidad con valores de 58 ºC a 30 cm y 47 °C a 90 cm con una variación de 11 ºC. Los resultados de los análisis previos a la solarización mostraron presencia de la bacteria Escherichia coli y Salmonella spp., en muestreos posteriores sólo en el testigo se encontró a estos patógenos.The present work was carried out with the purpose of evaluating plastic covers, to use them in solarization of bovine manure, as an active method that can achieve pathogens deactivation, to obtain an organic and innocuous residual. In months of June and July of 2004, were compared stack treatments of manure covered with transparent plastic without albedo of 100 µm thickness, one with single cover, another with double cover and without cover a control one. Samples of solarized manure and without solarization were taken, to carry out sowing in culture media of potato-dextrose-agar, to detect coprophilous fungi as well as to detect Escherichia coli and

  11. Climate under cover

    CERN Document Server

    Takakura, Tadashi

    2002-01-01

    1.1. INTRODUCTION Plastic covering, either framed or floating, is now used worldwide to protect crops from unfavorable growing conditions, such as severe weather and insects and birds. Protected cultivation in the broad sense, including mulching, has been widely spread by the innovation of plastic films. Paper, straw, and glass were the main materials used before the era of plastics. Utilization of plastics in agriculture started in the developed countries and is now spreading to the developing countries. Early utilization of plastic was in cold regions, and plastic was mainly used for protection from the cold. Now plastic is used also for protection from wind, insects and diseases. The use of covering techniques started with a simple system such as mulching, then row covers and small tunnels were developed, and finally plastic houses. Floating mulch was an exception to this sequence: it was introduced rather recently, although it is a simple structure. New development of functional and inexpensive films trig...

  12. 废旧聚苯乙烯泡沫塑料的回收与再生方法∗%Polystyrene Foamed Plastic Recovery and Regeneration Process Research

    Institute of Scientific and Technical Information of China (English)

    左艳梅; 傅智盛

    2015-01-01

    Polystyrene foam has a low density,low water absorption,good acid and heat insulation,shock,etc. So it is widely used as machinery,household appliances,precision instruments,glassware cushion packaging and snack food packaging. Because of its large size, light weight, chemically more stable, resulting in a waste of resources. This paper focuses on the energy and resource shortages today,waste Styrofoam how to change waste into treasure, which is reasonable recycling,resource conservation,achieve a reduction of environmental pollution.%聚苯乙烯泡沫塑料具有密度低、吸水率低、耐酸碱、隔热隔音性好、防震等优点,被广泛用做机械设备、家用电器、精密仪器仪表、玻璃器皿的缓冲包装及快餐食品的包装。由于其体积大、重量轻、化学性质比较稳定,造成资源的浪费。该文着重研究在能源和资源面临短缺的今天,废弃聚苯乙烯泡沫塑料如何变废为宝,将其进行合理的再生利用,节约资源,实现减少环境污染。

  13. 马铃薯大棚套黑膜覆盖栽培技术%Planting Potato Using Black Plastic Film Mulching in an Anti-fogging Agricultural Plastic Film Covered Tunnel

    Institute of Scientific and Technical Information of China (English)

    林长治

    2013-01-01

    Potato has become a main crop in winter cropping system in Changle, but due to differences in cultivation, management and variation in annual climate conditions, potato yield and quality vary to a large extent. Planting potato using black plastic film mulching combined with drip irrigation under the mulching for fertigation in an anti-fogging agricultural plastic film covered tunnel provides potato a stable entironments for growth, and thereby increasing yield and quality of potato. Also by using this technique, potato could be marketed more than a month earlier. Therefore, the profit could be increased for potato farmers.%马铃薯已成为长乐市冬季农业生产的主要作物,但由于栽培技术与管理水平差异,年际气候变化较大,产量和品质也大不相同。马铃薯大棚套黑膜覆盖栽培技术通过构建温室大棚覆盖塑料无滴膜,起垄播种后覆盖黑色地膜,膜下铺设灌溉和施肥用的滴灌带等方法,为马铃薯生长发育提供了一个相对稳定的生态环境,可有效地提高马铃薯的产量和品质,且比露地栽培提早一个多月上市,稳定增加农户种植效益。

  14. 微发泡木塑复合材料耐腐性能的研究%Research on Decay Resistance of Micro-foamed Wood Plastic Composites

    Institute of Scientific and Technical Information of China (English)

    朱远; 姜志宏

    2012-01-01

    Experiments were conducted on nature decay resistance of wood plastic composites (WPCs) with S different wood and plastic ratios. The results showed that nature decay resistance of WPCs was strong, the mass loss rate of specimens decayed increased with wood flour content, but always less than 3,5%. Analysis of variance demonstrated that wood flour content had great effect on mass loss rate of WPCs. Exponential function y = a x exp(x/b)+c could well fit the mean mass loss rate of 5 kinds of WPCs with determination coefficient of 0.92358. Analysis of SEM and DSC showed that wood-rotting fimgi mainly decayed the wood component of the specimens.%研究了5种不同木塑比的木塑复合材料的天然耐腐性能.结果表明:①木塑复合材料的天然耐腐性能为强耐腐等级,受菌侵染后质量损失率随着木粉含量的提高而增大,但均小于3.5%,方差分析表明,木粉含量对试件质量损失率的影响高度显著,指数函数y=a×exp(x/b)+c对5种木塑材料的平均质量损失率拟合结果较好,决定系数R2为0.923 58;②通过SEM和DSC分析,木塑材料受菌侵染后,主要是木质材料受到了破坏.

  15. Utilização de diferentes filmes plásticos como cobertura de abrigos para cultivo protegido = Use of different greenhouses plastic film as cover

    Directory of Open Access Journals (Sweden)

    José Weselli de Sá Andrade

    2011-07-01

    Full Text Available O presente projeto foi desenvolvido na Faculdade de Engenharia – Unesp, Campus de Ilha Solteira, no município de Ilha Solteira, Estado de São Paulo. Estudou-se o comportamento do ambiente em duas condições de ambiente protegido, com cobertura plástica do solo e em solo nu. Avaliaram-se as médias, por quinquídio, dos valores médios,máximos e mínimos diários de temperatura e umidade relativa do ar. As médias, por quinquídio, dos: valores médios diários de déficit de saturação de vapor d’água; dos totais diários de densidade de fluxo de radiação; das transmitâncias à radiação, em cada abrigo e asregressões lineares para estimativa dos totais diários de radiação no interior dos abrigos, em função do total diário de radiação em campo aberto. O ambiente protegido reduziu em relação ao campo aberto a densidade de fluxo de radiação solar, com maior intensidade, no abrigo coberto com filme plástico térmico difusor de luz. O maior efeito dos abrigos ocorreu sobre as temperaturas máximas, tendo maiores valores a estufa coberta com filme de polietileno convencional. Não ocorreram diferenças para umidade relativa do ar entre as estufas. O mulching plástico preto aumentou a temperatura do solo a 6 e 12 cm de profundidade.This project was developed in the Faculty of Engineering - Unesp, Campus of Ilha Solteira, in the municipality of Ilha Solteira – São Paulo State. We studied the environmental behavior under two conditions of protected environment, with plastic covering the soil and bare soil. It was evaluated the quinquidial averages, averages values, maximum and minimum daily temperature and relative humidity; quinquidial averages of the daily average values of deficiency of saturation of water vapor; the density of total daily flow of radiation; from transmission to radiation in each shelter and the linear regressions to estimate the total daily radiation inside the shelter, according to the daily total

  16. Coal-based carbon foams. Influence of the precursor coal

    Energy Technology Data Exchange (ETDEWEB)

    Montserrat Calvo; Roberto Garcia; Sabino R. Moinelo [Instituto Nacional del Carbon (CSIC), Oviedo (Spain)

    2007-07-01

    Carbon foams were obtained from several bituminous coals with different plasticity and volatile matter content by a two-stage thermal process. The first stage, a controlled carbonisation treatment under pressure at 450-500{sup o}C, is responsible for the final textural properties of the foam. In the second stage the carbonisation product was baked at 1100{sup o}C. The foams produced display a macroporous texture with plasticity, volatile matter content and maceral composition of the precursor coals having an influence on the apparent density and the pore size of the resultant porous products. 7 refs., 4 figs., 3 tabs.

  17. Absolute Hugoniot measurements for CH foams in the 1.5-8 Mbar range

    Science.gov (United States)

    Aglitskiy, Y.; Velikovich, A. L.; Schmitt, A. J.; Karasik, M.; Serlin, V.; Weaver, J. L.; Oh, J.; Obenschain, S. P.

    2016-10-01

    We report the absolute Hugoniot measurements for dry CH foams at 10% of solid polystyrene density. The 400 μm thick, 500 μm wide planar foam slabs covered with a 10 μm solid plastic ablator were driven with 4 ns long Nike KrF laser pulses whose intensity was varied between 10 and 50 TW/cm2. The trajectories of the shock front and the ablative piston, as well as the rarefaction fan emerging after the shock breakout from the rear surface of the target were clearly observed using the side-on monochromatic x-ray imaging radiography. From these measurements the shock density compression ratio and the shock pressure are evaluated directly. The observed compression ratios varied between 4 and 8, and the corresponding shock pressures - between 1.5 and 8 Mbar. The data was simulated with the FASTRAD3D hydrocode, using standard models of inverse bremsstrahlung absorption, flux-limited thermal conduction, and multi-group radiation diffusion. The demonstrated diagnostics technique applied in a cryo experiment would make it possible to make the first absolute Hugoniot measurements for liquid deuterium or DT-wetted CH foams, which is relevant for designing the wetted-foam indirect-drive ignition targets for NIF. This work was supported by the US DOE/NNSA.

  18. Nitrous oxide emissions from soils amended by cover-crops and under plastic film mulching: Fluxes, emission factors and yield-scaled emissions

    Science.gov (United States)

    Kim, Gil Won; Das, Suvendu; Hwang, Hyun Young; Kim, Pil Joo

    2017-03-01

    Assessment of nitrous oxide (N2O) emission factor (EF) for N2O emission inventory from arable crops fertilized with different nitrogen sources are under increased scrutiny because of discrepancies between the default IPCC EFs and low EFs reported by many researchers. Mixing ratio of leguminous and non-leguminous cover crop residues incorporation and plastic film mulching (PFM) in upland soil has been recommended as a vital agronomic practice to enhance yield and soil quality. However, how these practices together affect N2O emissions, yield-scaled emissions and the EFs remain uncertain. Field experiments spanning two consecutive years were conducted to evaluate the effects of PFM on N2O emissions, yield-scaled emissions and the seasonal EFs in cover crop residues amended soil during maize cultivation. The mixture of barley (Hordeum vulgare) and hairy vetch (Vicia villosa) seeds with 75% recommended dose (RD 140 kg ha-1) and 25% recommended dose (RD 90 kg ha-1), respectively, were broadcasted during the fallow period and 0, 25, 50 and 100% of the total aboveground harvested biomass that correspond to 0, 76, 152 and 304 kg N ha-1 were incorporated before maize transplanting. It was found that the mean seasonal EFs from cover crop residues amended soil under No-mulching (NM) and PFM were 1.13% (ranging from 0.81 to 1.23%) and 1.49% (ranging from 1.02 to 1.63%), respectively, which are comparable to the IPCC (2006) default EF (1%) for emission inventories of N2O from crop residues. The emission fluxes were greatly influenced by NH4+sbnd N, NO3--N, DOC and DON contents of soil. The cumulative N2O emissions markedly increased with the increase in cover crop residues application rates and it was more prominent under PFM than under NM. However, the yield-scaled emissions markedly decreased under PFM compared to NM due to the improved yield. With relatively low yield-scaled N2O emissions, 25% biomass mixing ratio of barley and hairy vetch (76 kg N ha-1) under PFM could be

  19. 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.

  20. Laser micromachined wax-covered plastic paper as both sputter deposition shadow masks and deep-ultraviolet patterning masks for polymethylmethacrylate-based microfluidic systems

    Science.gov (United States)

    Fan, Yiqiang; Li, Huawei; Yi, Ying; Foulds, Ian G.

    2013-10-01

    We report a technically innovative method of fabricating masks for both deep-ultraviolet (UV) patterning and metal sputtering on polymethylmethacrylate (PMMA) for microfluidic systems. We used a CO laser system to cut the required patterns on wax-covered plastic paper; the laser-patterned wax paper will either work as a mask for deep-UV patterning or as a mask for metal sputtering. A microfluidic device was also fabricated to demonstrate the feasibility of this method. The device has two layers: the first layer is a 1-mm thick PMMA substrate that was patterned by deep-UV exposure to create microchannels. The mask used in this process was the laser-cut wax paper. The second layer, also a 1-mm thick PMMA layer, was gold sputtered with patterned wax paper as the shadow mask. These two pieces of PMMA were then bonded to form microchannels with exposed electrodes. This process is a simple and rapid method for creating integrated microfluidic systems that do not require cleanroom facilities.

  1. Design of Precision Plastic Injection Mold for Mobile Phone Cover%手机面盖精密注塑模具设计

    Institute of Scientific and Technical Information of China (English)

    张维合

    2012-01-01

    The design key points and instructions of a plastic injection mold for mobile phone cover with thin wall were introduced. Fixed mold slant lifting was adopted for inside molding, while "slant leader pin + slider" was adopted for outside core pulling and the secondary ejection was adopted. The classic exhaust air system and guide position system were designed. The structure of the mold was tight and the rigidity was excellent, it was a precision mold with long lifetime.%介绍了一款薄壁手机面盖注塑模具的设计要点和注意事项,模具采用定模斜顶进行内侧成型,动模则采用“斜导柱+滑块”进行外侧抽芯,采用二次脱模结构,设计了先进的模具排气系统和导向定位系统,该模具结构紧凑,刚性极佳,是一副长寿命的精密注塑模具.

  2. Laser micromachined wax-covered plastic paper as both sputter deposition shadow masks and deep-ultraviolet patterning masks for polymethylmethacrylate-based microfluidic systems

    KAUST Repository

    Fan, Yiqiang

    2013-12-16

    We report a technically innovative method of fabricating masks for both deep-ultraviolet (UV) patterning and metal sputtering on polymethylmethacrylate (PMMA) for microfluidic systems. We used a CO2 laser system to cut the required patterns on wax-covered plastic paper; the laser-patterned wax paper will either work as a mask for deep-UV patterning or as a mask for metal sputtering. A microfluidic device was also fabricated to demonstrate the feasibility of this method. The device has two layers: the first layer is a 1-mm thick PMMA substrate that was patterned by deep-UV exposure to create microchannels. The mask used in this process was the laser-cut wax paper. The second layer, also a 1-mm thick PMMA layer, was gold sputtered with patterned wax paper as the shadow mask. These two pieces of PMMA were then bonded to form microchannels with exposed electrodes. This process is a simple and rapid method for creating integrated microfluidic systems that do not require cleanroom facilities.

  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. 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.

  5. 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.

  6. 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.

  7. Healing reaction to mammary prostheses covered by textured silicone and silicone foam in rats Reação capsular aos revestimentos de próteses mamárias de silicone texturizado e espuma de silicone em ratos

    Directory of Open Access Journals (Sweden)

    Cynthia Maria S. Rojas Balderrama

    2009-10-01

    Full Text Available PURPOSE: To compare the capsular reaction to two different coverings of silicone prosthesis through the biophysical characteristic of adherence and microscopical aspects of the inflammatory reaction and collagen formation. METHODS: Thirty two Wistar rats were used. In the dorsum of each animal a silicone elastomer with a smooth superficies and another coated with texturized silicone (Mentor was implanted. Another one, with the same smooth superficies and other coated with silicone foam (Lifesil, making up in each side, of the dorsum, the texturized and silicone foam group respectively. The animals were split into four groups to be evaluated at 7, 14, 30 and 60 days. On the evaluation dates the implant adherence was verified witch a tensiometer and the values in kgf were obtained. The material was sent to histological analysis with hematoxilin-eosin and picrosirius colorations, to evaluate the inflammatory reaction and collagen synthesis, respectively. The obtained data were submitted to statistical treatment. RESULTS: There was more adherence of the tissue to the silicone foam (POBJETIVO: Comparar a reação capsular de dois revestimentos de próteses de silicone através da característica biofísica de aderência e dos aspectos microscópicos de reação inflamatória e formação de colágeno. MÉTODOS: Implantaram-se no dorso de 32 ratos duas membranas de silicone ambas possuindo uma superfície lisa e outra diferindo em sua estrutura. Estes revestimentos foram de espuma de silicone (LifeSil ou silicone texturizado (Mentor. Os dois grupos foram divididos em quatro sub-grupos conforme o tempo de pós-operatório avaliado: 7, 14, 30 e 60 dias. Obteve-se material para análise biofísica de aderência, a qual foi realizada com tensiômetro para obtenção de valores em kgf. O estudo microscópico da reação inflamatória e síntese de colágeno foi realizado com colorações de hematoxilina-eosina e picrosirius. Os dados foram submetidos a

  8. 33 CFR 183.552 - Plastic encased fuel tanks: Installation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Plastic encased fuel tanks... § 183.552 Plastic encased fuel tanks: Installation. (a) Each fuel tank encased in cellular plastic foam or in fiber reinforced plastic must have the connections, fittings, and labels accessible...

  9. 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

  10. 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.

  11. 46 CFR 179.240 - Foam flotation material.

    Science.gov (United States)

    2010-10-01

    ..., see 46 CFR 175.600). The fire resistance test is not required. (2) Foam may be installed only in void... area that may be exposed to water; and (ii) Have a protective cover, approved by the cognizant OCMI, to protect it from damage; (7) A water submergence test must be conducted on the foam for a period of at...

  12. 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.

  13. 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).

  14. Coalescence In Draining Foams Made of Very Small Bubbles

    Science.gov (United States)

    Briceño-Ahumada, Zenaida; Drenckhan, Wiebke; Langevin, Dominique

    2016-03-01

    We studied the stability of foams containing small bubbles (radius ≲ 50 μ m ). The foams are made from aqueous surfactant solutions containing various amounts of glycerol. The foams start breaking at their top, when the liquid volume fraction has decreased sufficiently during liquid drainage. Unlike in foams with larger bubbles, the liquid fraction at which the foam destabilizes is surprisingly high. In order to interpret this observation we propose that film rupture occurs during reorganization events (T 1 ) induced by bubble coarsening, which is particularly rapid in the case of small bubbles. New films are therefore formed rapidly and if their thickness is too small, they cannot be sufficiently covered by surfactant and they break. Using literature data for the duration of T 1 events and the thickness of the new films, we show that this mechanism is consistent with the behavior of the foams studied.

  15. 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.

  16. Armazenamento refrigerado da uva de mesa 'Romana' (A1105 cultivada sob cobertura plástica Cold storage of 'Romana' (A1105 table grape cultivated under plastic cover

    Directory of Open Access Journals (Sweden)

    Jorge Lulu

    2005-08-01

    Full Text Available A videira é uma das principais fruteiras cultivadas em todo o mundo e atualmente a preferência por uvas do tipo "sem sementes" ou "apirênicas" vem aumentando gradativamente no mercado interno brasileiro. A cultivar 'Romana' (A1105 tem mostrado grande potencial como nova alternativa de uva de mesa apirênica na região de Jundiaí - SP. No entanto, a qualidade dos cachos tem sido afetada pela ocorrência de chuvas na época da colheita, propiciando a incidência de rachaduras nas bagas ("cracking" e podridões. Visando a solucionar essa dificuldade, foram conduzidos experimentos de campo em vinhedo cultivado em cortina dupla e sob cobertura plástica. Após a colheita, foram coletadas oito amostras com seis cachos cada, que foram armazenadas a 3 ºC e submetidas a avaliações de qualidade por um período máximo de 36 dias. A perda de massa ultrapassou o valor de 6% após três semanas de armazenamento refrigerado, quando apresentou sinais de murchamento das bagas, concluindo-se que o período máximo de armazenamento em câmara fria para a cultivar 'Romana' (A1105 foi de 21 dias.The grapevine is one of the most cultivated fruit crop and nowadays the preference for seedless grapes is gradualy increasing in the Brazilian internal market. The table grape cultivar 'Romana' (A1105 has been showing potential as a new option for the growers from Jundiaí - SP, Brazil, as a seedless grape. However the bunch quality has been affected by rain at the harvest allowing the incidence of cracking and bunch rot. Aiming to solve this problem a field trial was carried out with grapes cultivated under plastic cover and Geneva Double Curtain training system. After harvest, eight samples of six bunches each were taken and stored at 3 ºC and evaluated for quality during a period of 36 days. After three weeks of storage, the weight loss was higher than 6%, showing bunch fade and the rot bunch increased significantly. It was concluded that maximum shelf life for

  17. Mechanical properties and network structure of wheat gluten foams.

    Science.gov (United States)

    Blomfeldt, Thomas O J; Kuktaite, Ramune; Johansson, Eva; Hedenqvist, Mikael S

    2011-05-09

    This Article reports the influence of the protein network structure on the mechanical properties of foams produced from commercial wheat gluten using freeze-drying. Foams were produced from alkaline aqueous solutions at various gluten concentrations with or without glycerol, modified with bacterial cellulose nanosized fibers, or both. The results showed that 20 wt % glycerol was sufficient for plasticization, yielding foams with low modulus and high strain recovery. It was found that when fibers were mixed into the foams, a small but insignificant increase in elastic modulus was achieved, and the foam structure became more homogeneous. SEM indicated that the compatibility between the fibers and the matrix was good, with fibers acting as bridges in the cell walls. IR spectroscopy and SE-HPLC revealed a relatively low degree of aggregation, which was highest in the presence of glycerol. Confocal laser scanning microscopy revealed distinct differences in HMW-glutenin subunits and gliadin distributions for all of the different samples.

  18. Visualization of the Crystallization in Foam Extrusion Process

    Science.gov (United States)

    Tabatabaei Naeini, Alireza

    In this study, crystal formation of polypropylene (PP) and poly lactic acid (PLA) in the presence of CO2 in foam extrusion process was investigated using a visualization chamber and a CCD camera. The role of pre-existing crystals on the foaming behavior of PP and PLA were studied by characterizing the foam morphology. Visualization results showed that crystals formed within the die before foaming and these crystals affect the cell nucleation behavior and expansion ratio of PP and PLA significantly. Due to the fast crystallization kinetics of PP, crystallinity should be optimum to achieve uniform cell structure with high cell density and high expansion ratio. In PLA, enhancement of crystallinity is crucial for getting foam with a high expansion ratio. It was also visualized that CO2 significantly suppresses the crystallization temperature in PP through the plasticization effect as well as its influence on flow induced crystallinity.

  19. Efeito do microclima na qualidade da uva de mesa 'Romana' (A 1105 cultivada sob cobertura plástica Effect of microclimate in the quality of 'Romana' (A 1105 table grape cultivated under plastic cover

    Directory of Open Access Journals (Sweden)

    Jorge Lulu

    2005-12-01

    period, leading to incidence of berry cracking and rot. Aiming to verify the possibility of growing this table grape under plastic cover conditions a field trial was done in a vineyard grown in Jundiaí, aiming to quantify microclimatic parameters inside and outside of the protected environment; the bunch quality at harvest and the period of cold storage of bunchs (post-harvest time. The average values of solar radiation transmissivity were decreasing as follow: effect of the plastic cover only> effect of the grapevine training system only> and combined effect of the plastic cover and training system. Analising the bunch quality parameters at harvest, significantly lower values of bunch rot were found for the plastic cover treatment in relation to the open sky grapevines. Also, the bunch weight was higher in the plastic cover treatment. The defects like deep and superficial damage were lower for the bunch harvested in the plastic cover treatment. So, it was concluded that the use of plastic cover for the 'Romana' (A 1105 table grape led to a better bunch quality, mainly due to the reduction of rot bunch incidence.

  20. 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.

  1. Deformation behavior of open-cell stainless steel foams

    Energy Technology Data Exchange (ETDEWEB)

    Kaya, A.C., E-mail: a.kaya@campus.tu-berlin.de; Fleck, C.

    2014-10-06

    This study presents the deformation and cell collapse behavior of open-cell stainless steel foams. 316L stainless-steel open-cell foams with two porosities (30 and 45 pores per inch, ppi) were produced with the pressureless powder metallurgical method, and tested in quasi-static compression. As a result of the manufacturing technique, 316L stainless steel open-cell foams have a high amount of microporosity. The deformation behavior was investigated on a macroscopic scale by digital image correlation (DIC) evaluation of light micrographs and on the microscopic scale by in situ loading of cells in the scanning electron microscope. The deformation behavior of the metal foams was highly affected by microstructural features, such as closed pores and their distribution throughout the foam specimen. Moreover, the closed pores made a contribution to the plateau stress of the foams through cell face stretching. Strut buckling and bending are the dominant mechanisms in cell collapse. Although there are edge defects on the struts, the struts have an enormous plastic deformation capability. The cell size of the steel foams had no significant effect on the mechanical properties. Due to the inhomogeneities in the microstructure, the measured plateau stresses of the foams showed about 20% scatter at the same relative density.

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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...

  7. Laser interaction with low-density carbon foam

    Indian Academy of Sciences (India)

    S Chaurasia; S Tripathi; D S Munda; G Mishra; C G Murali; N K Gupta; L J Dhareshwar; A K Rossall; G J Tallents; Rashmi Singh; D K Kohli; R K Khardekar

    2010-12-01

    Experiments were performed with a 15 J/500 ps Nd:glass laser ( = 1064 nm) focussed to an intensity > 1014 W/cm2 . X-ray emissions from carbon foam and 5 % Pt-doped carbon foam of density 150–300 mg/cc were compared with that of the solid carbon targets. The thickness of the carbon foam was 15 m on a graphite substrate. X-ray emission was measured using semiconductor X-ray diodes covered with various filters having transmissions in different X-ray spectral ranges. It covered X-ray spectrum of 0.8–8.5 keV range. The X-ray emission in the soft X-ray region was observed to increase to about 1.8 times and 2.3 times in carbon foam and Pt-doped foam, respectively with respect to solid carbon. In hard X-rays, there was no measurable difference amongst the carbon foam, Pt-doped carbon foam and solid carbon. Scanning electron microscope (SEM) analysis demonstrates that foam targets smoothens the crater formed by the laser irradiation.

  8. C-Streams. Material and energy flows of non-energy use throughout the life cycle, and CO{sub 2} abatement by products of the chemical industry - Current situation and perspectives. Vol. 2. The use of plastic foams for thermal insulation of buildings and the resulting effects on energy demand and carbon dioxide emission; C-STROeME. Material- und Energiestroeme des nichtenergetischen Verbrauchs ueber den Lebenszyklus und CO{sub 2}-Minderung durch Produkte der Chemischen Industrie - Stand und Perspektiven. Bd. 2. Einfluss des Einsatzes von Kunststoffen auf den Energiebedarf und die energiebedingten CO{sub 2}-Emissionen im Bereich der Waermedaemmung

    Energy Technology Data Exchange (ETDEWEB)

    Marscheider-Weidemann, F.; Reichert, J.

    1999-06-01

    The aim of this study is to analyse the net balances with regard to energy and CO{sub 2} for plastic foams used in thermal insulation. To this end, the energy demand required to produce the foams is determined first of all, and a calculation is then made of the amount of energy saved through the reduction in heat demand. By calculating the difference between these two totals the net balance is established. By analogy, the net CO{sub 2} emissions are also determined. All calculations are based on the total annual sales volumes in Germany of polyurethane foam (PUR), expanded polystyrene foam (EPS) and polystyrene extruder foam (XPS). Data published by the Association of Plastics Manufacturers in Europe (APME) are used to calculate the energy needed to manufacture these foams. To determine the amount of energy saved by using these insulating materials, the sales volumes in cubic metres (m{sup 3}) are first of all converted to square metres (m{sup 2}) based on the average insulation thicknesses as published in the literature. Subsequently, the various insulation materials are allocated first of all to different types of buildings and then to a specific application, i.e. walls, roof or cellar. By using average values for heat conduction (both with and without insulation) a calculation is finally made of the energy saving and reduction in emissions of CO{sub 2} that have been achieved from applying the foams. Because of their historical relevance in environmental policy, the use of CFCs as foaming agents has also been taken into account in this study. (orig.)

  9. Damage to thermal insulation foams in low-slope roof systems caused by simulated foot traffic

    National Research Council Canada - National Science Library

    Liu, Karen K; Booth, R. J

    1999-01-01

    The results indicated that common.ly used foam plastic roof insulations will be damaged if exposed to foot traffic, and that their protection with fibrous overlay boards as recommended by roofing contractor associations continues...

  10. Methods of Cold Soaking, Foam Plastics Enrichment and Inductive Coupling Plasma Atomic Emission Spectrometry%冷浸取--泡塑富集-电感耦合等离子体发射光谱法测定化探样品中的超痕量金铂钯研究

    Institute of Scientific and Technical Information of China (English)

    闵慧英; 袁蕙霞; 郭玉翠

    2015-01-01

    建立了冷浸--泡沫塑料富集,采用 ICP-AES 测定地球化学勘探样品中超痕量金、铂、钯的方法,并试验了冷浸取、泡沫塑料富集时各种因素的影响;确定了采用氯化钠、盐酸和高锰酸钾冷浸取分解试样,以泡沫塑料富集、灰化,残渣用王水溶解,用电感耦合等离子体发射光谱法测定的条件。该方法检出限分别为:Au 0.039ng/g,Pt 0.040ng/g,Pd 0.058ng/g;回收率为95.6%~102.5%之间;测量精密度( RSD%)为:Au 4.85%,Pt 5.76%,Pd 6.45%。采用该方法测定了国家一级地球化学标准物质中的痕量 Au,Pt,Pd,测定值与标准值符合规范要求。%In this paper, we set up the enrichment of cold soaking foam plastics by adopting the method of ICP-AES to test the ultra-trace of gold, platinum and palladium from the geochemical exploration sample and studied all kinds of effective factors in cold soaking foam plastics enrichment. And we confirmed the requirements of using sodi-um chloride, hydrochloric acid and potassium permanganate cold soak-ing to decompose the sample, using foam plastics to enrich and ash, aqua regia to dissolve residue, and measuring by inductive coupling Plasma Atomic Emission Spectrometry. The detection limits of this method are as follows: detection limit: Au 0.039ng/g, Pt 0.040ng/g, Pd 0.058ng/g; recovery rate: between 95.9% and 102.2%; relative stan-dard deviation (RSD%): Au 4.85%,Pt 5.76%,Pd 6.45%.We tested the trace amount of Au, Pt and Pd in the country-level geochemistry stan-dard substance. The measured value is consistent with the normalized value.

  11. 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...

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. Journal of CHINA PLASTICS

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Journal of CHINA PLASTICS was authorized and approved by The State Committee of Science and Technology of China and The Bureau of News Press of China, and published by The China Plastics Processing Industry Association,Beijing Technology and Business University and The Institute of Plastics Processing and Application of Light Industry, distributed worldwide. Since its birth in 1987, CHINA PLASTICS has become a leading magazine in plastics industry in China, a national Chinese core journal and journal of Chinese scientific and technological article statistics. It is covered by CA.

  17. Aktau Plastics Plant Explosives Material Report

    Energy Technology Data Exchange (ETDEWEB)

    CASE JR.,ROGER S.

    1999-12-01

    The U.S. Department of Energy (DOE) has been cooperating with the Republic of Kazakhstanin Combined Threat Reduction (CTR) activities at the BN350 reactor located at the Mangyshlak Atomic Energy Complex (MAEC) in the city of Aktau, Kazakhstan since 1994. DOE contract personnel have been stationed at this facility for the last two years and DOE representatives regularly visit this location to oversee the continuing cooperative activities. Continued future cooperation is planned. A Russian news report in September 1999 indicated that 75 metric tons of organic peroxides stored at the Plastics Plant near Aktau were in danger of exploding and killing or injuring nearby residents. To ensure the health and safety of the personnel at the BN350 site, the DOE conducted a study to investigate the potential danger to the BN350 site posed by these materials at the Plastics Plant. The study conclusion was that while the organic peroxides do have hazards associated with them, the BN350 site is a safe distance from the Plastics Plant. Further, because the Plastics Plant and MAEC have cooperative fire-fighting agreements,and the Plastics Plant had exhausted its reserve of fire-fighting foam, there was the possibility of the Plastics Plant depleting the store of fire-fighting foam at the BN350 site. Subsequently, the DOE decided to purchase fire-fighting foam for the Plastics Plant to ensure the availability of free-fighting foam at the BN350 site.

  18. Permeability studies on 3D Ni foam/graphene composites

    Science.gov (United States)

    Yang, Zhuxian; Chen, Hongmei; Wang, Nannan; Xia, Yongde; Zhu, Yanqiu

    2017-09-01

    This study investigates the permeability of new 3D Ni foam/graphene composites (Ni foam covered with graphene) using compressed air, Ar and N2 as the probe gases. The results show that the introduction of graphene on the surface of Ni foam via in situ chemical vapour deposition is not detrimental to the permeability of the composites; on the contrary, in some cases it improves permeability. A modified Ergun-type correlation has been proposed, which represents very well the permeability of the Ni foam/graphene composites, especially at flow rates higher than 0.3 m s-1. Further studies show that graphene also helps to improve the thermal conductivity of the composite. These results suggest that the graphene involvement will make the Ni foam/graphene composite a good candidate for potential applications such as filters or heat exchangers suitable for working under harsh conditions such as at high temperatures, in corrosive environments, etc.

  19. Plastic debris in 29 Great Lakes tributaries: Relations to watershed attributes and hydrology

    Science.gov (United States)

    Baldwin, Austin K.; Corsi, Steven; Mason, Sherri A.

    2016-01-01

    Plastic debris is a growing contaminant of concern in freshwater environments, yet sources, transport, and fate remain unclear. This study characterized the quantity and morphology of floating micro- and macroplastics in 29 Great Lakes tributaries in six states under different land covers, wastewater effluent contributions, population densities, and hydrologic conditions. Tributaries were sampled three or four times each using a 333 μm mesh neuston net. Plastic particles were sorted by size, counted, and categorized as fibers/lines, pellets/beads, foams, films, and fragments. Plastics were found in all 107 samples, with a maximum concentration of 32 particles/m3 and a median of 1.9 particles/m3. Ninety-eight percent of sampled plastic particles were less than 4.75 mm in diameter and therefore considered microplastics. Fragments, films, foams, and pellets/beads were positively correlated with urban-related watershed attributes and were found at greater concentrations during runoff-event conditions. Fibers, the most frequently detected particle type, were not associated with urban-related watershed attributes, wastewater effluent contribution, or hydrologic condition. Results from this study add to the body of information currently available on microplastics in different environmental compartments, including unique contributions to quantify their occurrence and variability in rivers with a wide variety of different land-use characteristics while highlighting differences between surface samples from rivers compared with lakes.

  20. Plastic Debris in 29 Great Lakes Tributaries: Relations to Watershed Attributes and Hydrology.

    Science.gov (United States)

    Baldwin, Austin K; Corsi, Steven R; Mason, Sherri A

    2016-10-04

    Plastic debris is a growing contaminant of concern in freshwater environments, yet sources, transport, and fate remain unclear. This study characterized the quantity and morphology of floating micro- and macroplastics in 29 Great Lakes tributaries in six states under different land covers, wastewater effluent contributions, population densities, and hydrologic conditions. Tributaries were sampled three or four times each using a 333 μm mesh neuston net. Plastic particles were sorted by size, counted, and categorized as fibers/lines, pellets/beads, foams, films, and fragments. Plastics were found in all 107 samples, with a maximum concentration of 32 particles/m(3) and a median of 1.9 particles/m(3). Ninety-eight percent of sampled plastic particles were less than 4.75 mm in diameter and therefore considered microplastics. Fragments, films, foams, and pellets/beads were positively correlated with urban-related watershed attributes and were found at greater concentrations during runoff-event conditions. Fibers, the most frequently detected particle type, were not associated with urban-related watershed attributes, wastewater effluent contribution, or hydrologic condition. Results from this study add to the body of information currently available on microplastics in different environmental compartments, including unique contributions to quantify their occurrence and variability in rivers with a wide variety of different land-use characteristics while highlighting differences between surface samples from rivers compared with lakes.

  1. Nanoclay reinforced thermoplastic toughened epoxy hybrid syntactic foam: Surface morphology, mechanical and thermo mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Asif, A. [Propellants and Special Chemicals Group, Propellants Polymers Chemicals and Materials Entity, Vikram Sarabhai Space Centre, Trivandrum 695022 (India); Rao, V. Lakshmana, E-mail: rao_vl@yahoo.co.in [Propellants and Special Chemicals Group, Propellants Polymers Chemicals and Materials Entity, Vikram Sarabhai Space Centre, Trivandrum 695022 (India); Ninan, K.N. [Propellants and Special Chemicals Group, Propellants Polymers Chemicals and Materials Entity, Vikram Sarabhai Space Centre, Trivandrum 695022 (India)

    2010-09-15

    Epoxy hybrid syntactic foams were prepared with diglycidyl ether of bisphenol A (DGEBA) epoxy resin, diamino diphenyl sulfone (DDS), hydroxyl terminated polyether ether ketone having pendant methyl group (PEEKMOH), microballoon and nanoclay. The density of the foam was maintained between 0.6 and 0.72 g/cc for all compositions. Fracture toughness, tensile, flexural and compressive properties of the foam were evaluated with respect to clay and PEEKMOH concentrations. Morphology by X-ray diffraction revealed that the clay particles within the epoxy resin were intercalated for all the compositions of the syntactic foam. Fracture toughness and mechanical properties of the syntactic foam were significantly improved by the addition of nanoclay. A further enhancement in fracture toughness and mechanical properties was observed by the addition of PEEKMOH. The hybrid epoxy syntactic foam thus prepared exhibited 58%, 77% and 38% improvement in compressive strength, percentage elongation and fracture toughness, respectively, compared to the neat epoxy syntactic foam. The specific mechanical properties were found to be higher for the epoxy hybrid syntactic foam containing 3 wt% nanoclay and 3 wt% of PEEKMOH combination. The storage and loss modulus of the syntactic foam were also increased by the addition of nanoclay and PEEKMOH. A marginal improvement in T{sub g} was observed with clay incorporated syntactic foam. SEM analysis revealed that increased microcracking, crack path deflection, matrix deformation, plastic deformation, rupture of microballoons and debonded microspheres influencing on fracture toughness and mechanical properties of epoxy hybrid syntactic foam.

  2. 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

  3. 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% .

  4. Study on plastic sheet-covered cultivation technique on pollution-free potato%无公害马铃薯地膜覆盖栽培技术

    Institute of Scientific and Technical Information of China (English)

    吴文星

    2015-01-01

    从田块选择、品种选择、播前准备、播种、田间管理、病虫害防治及采收等方面总结了无公害马铃薯地膜覆盖栽培技术.%In this paper,the plastic sheet-coVered cultiVation techniques on pollution-free potato were summarized from the aspects of field selection,Variety selection,pretreatment before sowing,sowing,field management,disease and pest control, harVesting,and so on.

  5. Indentation of aluminium foam at low velocity

    Directory of Open Access Journals (Sweden)

    Shi Xiaopeng

    2015-01-01

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

  6. Industrialization of Technology on Bio-degradable Plastics

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ On August 14, 2004, aresearch project titled "Preparation of Aliphatic Ester Polycarbonate and Degradable Foam Plastics by Using Carbon Dioxide" passed its technical appraisal by experts under the sponsorship of the National Bureau of Environmental Protection.

  7. 塑料薄膜覆盖对牛粪便温室气体排放的影响%Effects of plastic sheet covering on greenhouse gas emission from beef cattle manure during storage

    Institute of Scientific and Technical Information of China (English)

    孙凯佳; 戚鑫; 付彤; 李改英; 廉红霞; 高腾云

    2015-01-01

    为控制短期贮存畜禽粪便的温室气体排放,该文研究了塑料薄膜覆盖对肉牛粪便短期贮存过程中温室气体排放量的影响。试验采用静态箱-气相色谱法观测了秋季(日均22.87℃)肉牛粪便自然露天堆放(对照组)和塑料薄膜覆盖堆放(覆盖组)时温室气体的排放通量。结果表明:秋季覆盖塑料薄膜贮存粪便可使N2O和CO2的日均排放通量分别降低94.85%(P<0.01)和88.85%(P<0.01),并在试验前期(0~9 d)使CH4的日均排放通量降低了43.37%(P<0.05),但随后的10~30 d,覆盖组粪便CH4的日均排放通量极显著高于对照组(P<0.01)。结论:当环境温度在17.23~30.35℃时,覆盖塑料薄膜可以降低堆放贮存(0~30 d)粪便N2O和CO2的排放通量以及堆放初期(0~9 d)CH4的排放通量。因此,塑料薄膜覆盖贮存法可显著降低粪便堆放初期的温室气体排放。%In order to assess the effects of plastic sheet covering on CH4, N2O and CO2 emissions during short-term storage of beef cattle manure, the greenhouse gas emission rate was investigated in autumn (September 7, 2013 - October 6, 2013, average air temperature was 22.87℃) by the static chamber - gas chromatography (GC) method. Meanwhile, ambient air temperatures and manure temperatures (10 cm below the surface) were measured every 5 minutes using automatic temperature recorder. On the first day, manure samples were collected from the Simmental beef cattle (18-19 months old, average weight of 500 kg), mixed, homogenized and divided into 6 replicate piles (the length, width and height of every pile were 100, 100 and 20 cm, respectively). Every pile had 2 sampling sites. The following two different treatments were included in this experiment: natural storage group (control group) and plastic sheet cover storage group (covering group), and every group included 3 replicate piles and a total of 6 sampling sites. The

  8. 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.)

  9. 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.

  10. 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.

  11. 聚丙烯塑料输液瓶拉环盖内面无菌可靠性调查%The asepsis security of the interior covers of polypropylene plastic dropping bottle

    Institute of Scientific and Technical Information of China (English)

    徐雪芬

    2008-01-01

    目的 探讨聚丙烯甥料输液瓶拉环盖内面的无菌可靠性.方法 将聚丙烯塑料输液瓶随机分为2组:对照组42瓶用生理盐水棉签直接采集开启后的聚丙烯塑料输液瓶拉环盖内面样本,实验组42瓶分别用0.5%碘伏、75%乙醇棉签常规消毒开启后的聚丙烯甥料输液瓶拉环盖内面,待干燥后用生理盐水棉签采集样本.所取样本均由主管检验师接种于无菌普通琼脂营养平板.置于37℃恒温培养箱内培养,以观察细菌生长情况.结果 2组细菌生长差异有统计学意义,X2=46.791,P<0.01.结论 聚丙烯塑料输液瓶拉环盖内面必须严格执行常规消毒后方能应用于临床.%Objective To study the asepsis security of the interior cover of polypropylene plastic dropping bottle.Methods The whole samples were divided randomly into two groups,each group included 42 polypropylene plastic dropping bottles,Samples of the control group were collected from the interior covers of dropping bottles wiping with sterile normal saline cotton swabs.Samples of the experimental group were also collected from the interior covers wiping with sterile normal saline cotton swabs aher disinfected by 0.5%iodophors and 75%alcohol respectively.All samples were inoculated on the aseptic plain agar nutrition flat plate.then incubated in 37℃ incubaton to observe the growth of bacteria.Results There Was statistical significance between the two groups in the growth of bacteria,χ2=46.791,P<0.01.Conclusions The interior covers of polypropylene plastic dropping bottle should be disinfected strictly before they are used in clinic.

  12. 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.

  13. Disponibilidade hídrica, radiação solar e fotossíntese em videiras 'Cabernet Sauvignon' sob cultivo protegido Water supply, solar radiation and photosynthesis in 'Cabernet Sauvignon' grapevines under plastic covering

    Directory of Open Access Journals (Sweden)

    Clenilso Sehnen Mota

    2009-06-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos da cobertura de videira 'Cabernet Sauvignon' com lona plástica translúcida sobre a disponibilidade de luz e água, a concentração foliar de clorofila e a fotossíntese. As plantas com cinco anos de idade foram conduzidas em sistema 'Y' sobre porta-enxerto Paulsen 1103. O experimento seguiu o delineamento em blocos ao acaso, com dois tratamentos (plantas sem e com cobertura plástica e quatro repetições de 15 plantas (unidade experimental. A cobertura plástica reduziu o suprimento às plantas de radiações ultravioleta (UV, azul, verde, vermelho, vermelho distante e total (300-750 nm, bem como a disponibilidade hídrica nas camadas superficiais do solo (0-30 cm. As plantas cobertas apresentaram maior taxa fotossintética máxima e condutância estomática em relação às plantas descobertas. Os pontos de compensação e de saturação de luz, a eficiência quântica aparente, a respiração no escuro, a concentração foliar de clorofilas e o potencial hídrico foliar de base não foram influenciados pelo uso da cobertura plástica. A cobertura plástica reduziu a radiação e a disponibilidade hídrica nas camadas superficiais do solo, porém favoreceu a assimilação foliar de CO2.The objective of this work was to assess the effects of translucent plastic overhead cover on light and water supply of vineyard and leaf chlorophyll content and photosynthesis in grapevines. Five-year-old 'Cabernet Sauvignon' grapevines (Vitis vinifera L. grafted on Paulsen 1103 rootstock and raised as 'Y' management system were used. The experiment followed a randomized block design, with two treatments (uncovered and covered plants and four replicates of 15 plants (experimental unit. The plastic cover reduced the supply of ultraviolet (UV, blue, green, red, far red, and total (300-750 nm radiation to the plants, as well as the water availability at the superficial soil layers (0-30 cm. Covered plants had

  14. Synthesis of palm oil fatty acid as foaming agent for firefighting application

    Science.gov (United States)

    Rivai, M.; Hambali, E.; Suryani, A.; Fitria, R.; Firmansyah, S.; Pradesi, J.

    2017-05-01

    Many factors including natural factor, human carelessness, new land clearance or agricultural burning/act of vandalism and ground fire are suspected as the causes of forest fire. Foam, which cools the fire down, covers the burning material/fuel, and avoids contact between burning materials with oxygen, is an effective material used to fight large-scale fires. For this purpose, surfactant which can facilitate foam formation and inhibit the spread of smoke is required. This study was aimed at producing prototype product of foaming agent from palm oil and its formulation as a fire fighting material. Before the formulation stage, the foaming agent was resulted from saponification process of oleic, lauric, and palmitic acids by using NaOH and KOH alkaline. Foam stability was used as the main indicator of foaming agent. Results showed that potassium palmitate had the highest foam stability of 82% until the 3rd day. The best potassium palmitate concentration was 7%.

  15. 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...

  16. 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...

  17. 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.

  18. Plastic Surgery

    Science.gov (United States)

    ... Surgery? A Week of Healthy Breakfasts Shyness Plastic Surgery KidsHealth > For Teens > Plastic Surgery Print A A ... forehead lightened with a laser? What Is Plastic Surgery? Just because the name includes the word "plastic" ...

  19. Feasibility Study: Hollow Plastic Spheres to Increase Hydraulic Fluid Compressibility

    Science.gov (United States)

    1982-07-01

    MICROMECHANICS FAILURE CRITERIA FOR COMPOSITES ; AUTHOR: GREESCZUK, LONCIN, B. 5. POISSON’S RATIO FOR RIGID PLASTIC FOAMS; AUTHOR: RINDE...S.A. Thuysbaert A.Stevens N4 Schwartz SPRL Schulmon Plastics SA Polytexco PVBA Polyform SA Plastiques Manufactures Plastimetal PVBA S.A...Plastics Corp. Plastiques GM Ltd. Rochevert, Inc. Polysar Limited, Kayson Plastics Div. Canlew Chemicals, Ltd. 4th Fl., 8-1, Hong Chou S. Rd., Sec. 1

  20. The microstructural origin of strain hardening in two-dimensional open-cell metal foams

    NARCIS (Netherlands)

    Mangipudi, K. R.; van Buuren, S. W.; Onck, P. R.

    2010-01-01

    This paper aims at elucidating the microstructural origin of strain hardening in open-cell metal foams. We have developed a multiscale model that allows to study the development of plasticity at two length scales: (i) the development of plastic zones inside individual struts (microscopic scale) and

  1. Creative Design of Hot Runner Inverse-Installing Injection Mold for Plastic Cover%塑料面板的热流道倒装注塑模的创新设计

    Institute of Scientific and Technical Information of China (English)

    陈鹏; 刘仕昌; 徐秋红

    2013-01-01

    By analyzing the structure and the process characters of plastic cover,the mold structural design,working principle and design points,as well as the application of hot runner in this mold were introduced respectively. Proved by enterprise production practice,the mold structure design is reasonable,and can meet the requirements of the product structure and manufacturability.%通过对塑料面板的结构和工艺性分析,介绍了其注塑模的结构设计、工作原理、设计要点及热流道系统在该注塑模中的应用。经企业生产验证,注塑模结构设计合理,满足塑料面板的结构和工艺性要求。

  2. An Experiment on Prevention of Fruit Green Return for Summer Orange with Fruit Bagging and Plastic Film Covering%果实套袋与树冠盖膜防止夏橙果实返绿试验初报

    Institute of Scientific and Technical Information of China (English)

    卢柱雄; 王宣英; 李全德; 廖延华

    2011-01-01

    An experiment on prevention of fruit green return for summer orange with fruit bagging and plastic film covering had been held. The results showed that, the effect on prevention of fruit green return for fruit bagging treatment was extremely remarkable. It would provide a reliable basis for further study of fruit bagging and effectively prevent summer orange fruit green returning.%对夏橙进行田间果实套袋与树冠盖膜防止夏橙果实返绿试验。结果表明,果实套袋处理防止果实返绿效果极其显著,为进一步研究果实套袋、有效防止夏橙果实返绿提供可靠依据。

  3. 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.

  4. 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.

  5. Fabrication of aluminum foam from aluminum scrap Hamza

    Directory of Open Access Journals (Sweden)

    O. A. Osman1 ,

    2015-02-01

    Full Text Available In this study the optimum parameters affecting the preparation of aluminum foam from recycled aluminum were studied, these parameters are: temperature, CaCO3 to aluminum scrap wt. ratio as foaming agent, Al2O3 to aluminum scrap wt. ratio as thickening agent, and stirring time. The results show that, the optimum parameters are the temperature ranged from 800 to 850oC, CaCO3 to aluminum scrap wt. ratio was 5%, Al2O3 to aluminum scrap wt. ratio was 3% and stirring time was 45 second with stirring speed 1200 rpm. The produced foam apparent densities ranged from 0.40-0.60 g/cm3. The microstructure of aluminum foam was examined by using SEM, EDX and XRD, the results show that, the aluminum pores were uniformly distributed along the all matrices and the cell walls covered by thin oxide film.

  6. Light weight polarized polypropylene foam for noise shielding

    Science.gov (United States)

    Zelfer, Travis J.; Warne, Derik S.; Korde, Umesh A.

    2009-03-01

    The high levels of noise generated during launch can destroy sensitive equipment on space craft. Passive damping systems, like acoustic blankets, work to reduce the high frequency noise but do little to the low frequency noise (foams with high piezoelectric coupling constants are being used as new types of actuators and sensors. Further impedance control through the inverse piezoelectric effect will lead to a new "semi-active" approach that will reduce low frequency noise levels. Combining layers of conventional nonpiezoelectric foam and ferroelectret materials with a multiple loop feedback system will give a total damping effect that is adaptable over a wide band of low frequencies. This paper covers the manufacturing methods that were used to make polarized polypropylene foam, to test the foam for its polarized response and its noise shielding ability.

  7. Condições microclimáticas em um parreiral irrigado coberto com tela plástica Microclimate conditions inside an irrigated vineyard covered with a plastic screen

    Directory of Open Access Journals (Sweden)

    Marco Antônio Fonseca Conceição

    2009-06-01

    Full Text Available A região de Jales é uma das principais produtoras de uvas de mesa do Estado de São Paulo. As videiras da região são irrigadas e conduzidas, normalmente, no sistema latada, sendo comum, também, a utilização de coberturas com telas plásticas para a proteção contra granizo, pássaros e morcegos. Entretanto, a irrigação, o sistema de condução e a cobertura plástica podem modificar as condições microclimáticas no parreiral. O presente trabalho teve como objetivo comparar as condições meteorológicas no interior de um parreiral de uvas, na região de Jales, com as registradas a céu aberto. As avaliações foram realizadas na Estação Experimental de Viticultura Tropical da Embrapa Uva e Vinho, em Jales-SP, em uma área conduzida no sistema latada, coberta com tela plástica de polietileno e irrigada por microaspersão. Os dados meteorológicos foram registrados fora e no interior do parreiral, empregando-se dois sistemas automáticos de aquisição de dados, com registros efetuados a cada 15 minutos. Verificou-se que o uso da cobertura de tela plástica reduziu em 20%, em média, a radiação solar incidente (Rs acima do dossel. Os valores de Rs abaixo do dossel, durante o período de maior expansão foliar, chegaram a ser inferiores a 20% dos registrados a céu aberto. A temperatura e a umidade relativa do ar no interior do parreiral não apresentaram, em geral, diferenças para os valores registrados na estação meteorológica. Durante a irrigação, a temperatura do ar foi reduzida em 3%, e a umidade relativa do ar aumentou em 4%, em média, no interior do parreiral.Jales is one of the most important table grape producing regions of São Paulo State, Brazil. The grapevines are usually irrigated and cultivated using the pergola training system and, also, covered with a plastic screen to protect against hail, birds and bat attacks. Nevertheless, the irrigation, the training system and the plastic covering modify the

  8. 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...

  9. Aspiration tests in aqueous foam using a breathing simulator

    Energy Technology Data Exchange (ETDEWEB)

    Archuleta, M.M.

    1995-12-01

    Non-toxic aqueous foams are being developed by Sandia National Laboratories (SNL) for the National Institute of Justice (NIJ) for use in crowd control, cell extractions, and group disturbances in the criminal justice prison systems. The potential for aspiration of aqueous foam during its use and the resulting adverse effects associated with complete immersion in aqueous foam is of major concern to the NIJ when examining the effectiveness and safety of using this technology as a Less-Than-Lethal weapon. This preliminary study was designed to evaluate the maximum quantity of foam that might be aspirated by an individual following total immersion in an SNL-developed aqueous foam. A.T.W. Reed Breathing simulator equipped with a 622 Silverman cam was used to simulate the aspiration of an ammonium laureth sulfate aqueous foam developed by SNL and generated at expansion ratios in the range of 500:1 to 1000:1. Although the natural instinct of an individual immersed in foam is to cover their nose and mouth with a hand or cloth, thus breaking the bubbles and decreasing the potential for aspiration, this study was performed to examine a worst case scenario where mouth breathing only was examined, and no attempt was made to block foam entry into the breathing port. Two breathing rates were examined: one that simulated a sedentary individual with a mean breathing rate of 6.27 breaths/minute, and one that simulated an agitated or heavily breathing individual with a mean breathing rate of 23.7 breaths/minute. The results of this study indicate that, if breathing in aqueous foam without movement, an air pocket forms around the nose and mouth within one minute of immersion.

  10. Rheology of Foam Near the Order-Disorder Transition

    Science.gov (United States)

    Holt, R. Glynn; McDaniel, J. Gregory

    2001-01-01

    The first part of our research results are summarized in the recent journal publication: J. Gregory McDaniel and R. Glynn Holt, 'Measurement of aqueous foam rheology by acoustic levitation', Phys. Rev. E 61, 2204 (2000). This aspect of the work was a combination of experiment and analysis. We built a levitation system capable of acoustically levitating small samples of aqueous foam of arbitrary gas and liquid volume fractions. We then modulated the acoustic field to induce normal mode oscillations of the foam samples. The observables from the experiment were frequency and mode number. For dry (roughly > 70% gas by volume) foams and small deformations, we developed an effective medium, normal-modes analysis which took the frequency and mode number from experiment, and gave us the shear elastic modulus of the foam as a function of Poisson's ratio. The second part of our results may be found in a soon-to-be submitted manuscript 'Dynamics of aqueous foam drops', I.Sh. Akhatov, J.G. McDaniel and R.G. Holt, describing our modeling in the wet foam limit by considering the acoustic problem. This aspect of the research is purely theoretical. Beginning from a mass-conserving mixture law, the fully nonlinear equations of motion for a wet (roughly < 10% gas by volume) foam drop of initially spherical shape were derived. The frequencies for normal mode oscillations were derived in the linear inviscid limit. The nonlinear equations were numerically solved to elicit the motion of a foam drop under acoustic excitation. The role of the time-varying void fraction in breathing-mode oscillations is of particular interest. As of the end of the current (NAG#3-2121) grant, this work was not yet concluded. We continue to work on this aspect in order to extend the analysis to cover the transition regime of gas volume fractions, as well as to compare to experiments in the wet regime.

  11. 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.

  12. 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...

  13. Flutuação populacional de adultos de Anastrepha fraterculus (Wied. em cultivo protegido e convencional de videira Anastrepha fraterculus (Wied. adult seasonal fluctuation in plastic covering and conventional grapevine cultivation

    Directory of Open Access Journals (Sweden)

    Geraldo Chavarria

    2009-09-01

    Full Text Available A mosca-das-frutas sul-americana, Anastrepha fraterculus (Wiedemann, 1830 (Diptera: Tephritidae, é considerada praga-chave das fruteiras de clima temperado na região Sul do Brasil. No entanto, poucas informações encontram-se disponíveis quando a espécie está associada à cultura da videira. Neste trabalho, foi avaliado o efeito da cobertura plástica sobre a população de adultos de A. fraterculus durante o ciclo de cultivo da videira cv. Moscato Giallo. O experimento foi conduzido nos ciclos de 2005/06 e 2006/07, em vinhedo comercial localizado em Flores da Cunha-RS (latitude 29° 06' sul, longitude 51° 20' oeste e altitude de 541 m, coberto com plástico impermeável tipo ráfia (160 µm de 12 fileiras com 35 m, deixando-se cinco fileiras sem cobertura (controle. Os adultos foram monitorados nas duas áreas com armadilhas McPhail, utilizando-se como atrativo de proteína hidrolisada (BioAnastrepha® a 5%, no período de outubro a abril, nos dois ciclos. O pico populacional da espécie, nos dois ciclos, foi observado no período de maturação da uva. Não foram registradas diferenças significativas nas capturas entre as áreas, concluindo-se que a cobertura plástica não afeta a mobilidade e a flutuação populacional de A. fraterculus em cultivo protegido de videira.The South American Fruit Fly Anastrepha fraterculus (Wiedemann, 1830 (Diptera: Tephritidae is one of the most important pests of temperate fruits in Southern Brazil. Little information regarded to pest damage is available when this insect is associated with vineyards. In this work was evaluated the plastic cover effect on seasonal fluctuation of A. fraterculus adults in vineyards of cv. Moscato Giallo. The experiment was conducted on 2005/06 and 2006/07 seasons in a vineyard located in Flores da Cunha, RS (latitude 29° 06' South, longitude 51° 20' West and altitude 541 m, covered with an impermeable plastic cloth (2.65 m x 160 µm, in 12 rows with 35 m, with five rows

  14. Ultrasound estimation and FE analysis of elastic modulus of Kelvin foam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nohyu; Yang, Seung Yong [School of Mechatronics Engineering, Korea University of Technology and Education, Cheonan (Korea, Republic of)

    2016-02-15

    The elastic modulus of a 3D-printed Kelvin foam plate is investigated by measuring the acoustic wave velocity of 1 MHz ultrasound. An isotropic tetrakaidecahedron foam with 3 mm unit cell is designed and printed layer upon layer to fabricate a Kelvin foam plate of 14 mm thickness with a 3D CAD/printer using ABS plastic. The Kelvin foam plate is completely filled with paraffin wax for impedance matching, so that the acoustic wave may propagate through the porous foam plate. The acoustic wave velocity of the foam plate is measured using the time-of-flight (TOF) method and is used to calculate the elastic modulus of the Kelvin foam plate based on acousto-elasticity. Finite element method (FEM) and micromechanics is applied to the Kelvin foam plate to calculate the theoretical elastic modulus using a non-isotropic tetrakaidecahedron model. The predicted elastic modulus of the Kelvin foam plate from FEM and micromechanics model is similar, which is only 3-4% of the bulk material. The experimental value of the elastic modulus from the ultrasonic method is approximately twice as that of the numerical and theoretical methods because of the flexural deformation of the cell edges neglected in the ultrasonic method.

  15. Produtividade e qualidade da uva 'Cabernet Sauvignon'produzida sob cobertura de plástico em cultivo orgânico Productivity and quality of grape 'Cabernet Sauvignon' produced in organic sistem under plastic covering

    Directory of Open Access Journals (Sweden)

    Alessandra Maria Detoni

    2007-01-01

    quality of the grape 'Cabernet Sauvignon' cultivated under covering of plastic in organic production system. The experiment was accomplished in an organic orchard in the west area of the state of Paraná; the plants were conducted in espalier system, with plastic covering in the planting line. It was evaluated tenor of soluble solids (SS, titrable acidity (TA, pH, total antocyanins, productivity, number of bunches for plant and medium bunch weight. They were not found significant differences in the tenor of SS (17.3ºBrix, however the fruits under the covering presented larger tenors of TA and pH, 1.14 g 100 mL-1 and 3.4 respectively, that those picked from plants without the plastic covering, which presented TA of 0.87 g 100 mL-1 and pH of 3.5. The largest tenor of total antocyanins was verified in the plants out of the covering, with 22.8 mg L-1. In the protected plants, the production was larger (1769 g plant-1 than in the plants without covering (492 g plant-1, which presented high index of diseases. It is concluded that the plastic covering makes possible the cultivation of grape 'Cabernet Sauvignon' in the organic production system, for providing a decrease in the incidence of diseases.

  16. Using egg albumin foam to extinguish fires

    Directory of Open Access Journals (Sweden)

    Hytham A. Alsaati

    2003-12-01

    Full Text Available Oil, coal and chemical fires are often difficult to put out using water. In certain hydrocarbon fires, protein foam can extinguish fires better than water by keeping air (oxygen away from the flames and by ''blowing'' the flame away from its fuel source. Egg albumin is a relatively inexpensive protein and is representative of foaming proteins, which are candidates for use as fire suppression agents. This paper begins to deal with the effect of the foam bulk pH, foam protein concentration and generating air flow rate into the foam on the fire extinguishing time in laboratory experiments. A Bunsen burner was used to generate a small, controlled laboratory fire within a plastic container, which represented a point source in a partially open room in the experiments. The Bunsen burner represents a gaseous hydrocarbon fire, which can be difficult to extinguish. Both a low pH foam and one made with a high air flow rate favor a reduction in time required to put out the Bunsen burner flame.Chamas produzidas por óleo, carvão e produtos químicos (incêndios provocados são difíceis de ser extinguidos com água. Algumas chamas de hidrocarbonetos podem ser extinguidas por espumas protéicas melhor do que a manutenção de ar (oxigênio fora do alcance das chamas ou pelo sopramento da chama para longe da sua fonte. Albumina de ovo é uma proteína relativamente barata e é representativa dentre as proteínas usadas como espuma para a (supressão extinção de agentes causadores de incêndio. Este artigo trata do estudo do efeito do pH e concentração da espuma protéica, além da geração de ar no interior da espuma, sobre o tempo de extinção de incêndio em experimentos laboratoriais. Nos experimentos um bico de Bunsen foi usado para gerar uma pequena chama, controlada em um container de plástico, representando uma fonte pontual em um ambiente parcialmente aberto. A chama do bico de Bunsen representa uma chama gasosa de hidrocarbonetos, que são dif

  17. Mechanical properties of tannin-based rigid foams undergoing compression

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-25

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

  18. Novel Foams Based on Freeze-Dried Renewable Vital Wheat Gluten

    DEFF Research Database (Denmark)

    Blomfeldt, Thomas O.J.; Olsson, Richard T.; Menon, Mohan

    2010-01-01

    A new way of producing rigid or semi-rigid foams from vital wheat gluten using a freeze-drying process is reported. Water/gluten-based mixtures were frozen and freeze-dried. Different foam structures were obtained by varying the mixing process and wheat gluten concentration, or by adding glycerol...... or bacterial cellulose nanofibers. MIP revealed that the foams had mainly an open porosity peaking at 93%. The average pore diameter ranged between 20 and 73 µm; the sample with the highest wheat gluten concentration and no plasticizer had the smallest pores. Immersion tests with limonene revealed...

  19. Rigid polyurethane/oil palm fibre biocomposite foam

    Science.gov (United States)

    Alis, Adilah; Majid, Rohah A.; Nasir, Izzah Athirah Ahmad; Mustaffa, Nor Syatika; Hassan, Wan Hasamuddin Wan

    2017-07-01

    Rigid polyurethane (PU) biocomposite foam had been successfully prepared by reacting palm oil-derived polyol (PO-p) with polymeric 4, 4-diphenylmethane diisocynate (p-MDI). Two types of alkali-treated oil palm fibres namely, empty fruit bunch (EFB) and palm pressed fibre (PPF) were used as fillers to be incorporated into PU foam at 2.5 wt%, 5 wt% and 7.5 wt% fibre loadings. The effects of these fibres on surface morphology, compressive strength and thermal transition behaviours of biocomposite foams were investigated. Fourier transform infra-red (FTIR) analysis confirmed the formation of urethane linkages (-NHCOO) in all samples at 1530-1540 cm-1. Differential scanning calorimetry (DSC) analysis showed the average melting peak temperature (Tm) of biocomposite foams (132°C) were lower Tm than that of pure PU foam (161.67°C) and the increase amount of fibres did not give significant effect on the Tm of both biocomposite systems. Meanwhile, the microscopic images of PU-PPF foams exhibited smaller and uniform cell size morphologies compared with the PU-EFB foams that had coarse and irregular cell sizes, especially at 7.5wt% EFB. These findings were manifested with the gradually increase of compressive strength of PU-PPF at all PPF ratios while for PU-EFB system, the compressive strength increased up to 5 wt% before reduced at 7.5 wt% loading. It was thought due to the residual oil in PPF fibre had plasticized the PU matrix to a little extent, thus helping the dispersion of PPF fibre across the matrix.

  20. Structure and Compressive Properties of Invar-Cenosphere Syntactic Foams

    Directory of Open Access Journals (Sweden)

    Dung Luong

    2016-02-01

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

  1. 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℃.

  2. THE RESEARCH AND DESIGN FOR MULTIFUNCTIONAL PLASTIC SPIRAL COVER PRODUCTION LINE%多功能塑料螺旋护套生产线的研发设计

    Institute of Scientific and Technical Information of China (English)

    王镇江

    2011-01-01

    The multifunctional plastic spiral cover production line used for protecting high-pressure soft pipe was researched.Changing thick section extruding, an unique soft shaft revolving forming technology was adopted in this line. The results after use showed that the machine forming was excellent. Products fully met the requirements of engineering machinery industry and obtained better social and economic benefits.%研制了一种高压软管用多功能塑料螺旋保护套的生产线.该生产线采用变厚截面塑料挤出,是一种独特的软轴旋转成型技术.用户使用后证明,该生产线成型性能优良.生产的产品完全符合工程机械行业的要求,取得了较好的社会效益和经济效益.

  3. 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.

  4. 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...

  5. 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%.

  6. 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.

  7. 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.

  8. 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

  9. 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.)

  10. 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.

  11. 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...

  12. 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....

  13. 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...

  14. 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

  15. 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 ...

  16. 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.

  17. Supercritical CO2 Foaming of Thermoplastic Materials Derived from Maize: Proof-of-Concept Use in Mammalian Cell Culture Applications

    Science.gov (United States)

    Trujillo-de Santiago, Grissel; Portales-Cabrera, Cynthia Guadalupe; Portillo-Lara, Roberto; Araiz-Hernández, Diana; Del Barone, Maria Cristina; García-López, Erika; Rojas-de Gante, Cecilia; de los Angeles De Santiago-Miramontes, María; Segoviano-Ramírez, Juan Carlos; García-Lara, Silverio; Rodríguez-González, Ciro Ángel; Alvarez, Mario Moisés; Di Maio, Ernesto; Iannace, Salvatore

    2015-01-01

    Background Foams are high porosity and low density materials. In nature, they are a common architecture. Some of their relevant technological applications include heat and sound insulation, lightweight materials, and tissue engineering scaffolds. Foams derived from natural polymers are particularly attractive for tissue culture due to their biodegradability and bio-compatibility. Here, the foaming potential of an extensive list of materials was assayed, including slabs elaborated from whole flour, the starch component only, or the protein fraction only of maize seeds. Methodology/Principal Findings We used supercritical CO2 to produce foams from thermoplasticized maize derived materials. Polyethylene-glycol, sorbitol/glycerol, or urea/formamide were used as plasticizers. We report expansion ratios, porosities, average pore sizes, pore morphologies, and pore size distributions for these materials. High porosity foams were obtained from zein thermoplasticized with polyethylene glycol, and from starch thermoplasticized with urea/formamide. Zein foams had a higher porosity than starch foams (88% and 85%, respectively) and a narrower and more evenly distributed pore size. Starch foams exhibited a wider span of pore sizes and a larger average pore size than zein (208.84 vs. 55.43 μm2, respectively). Proof-of-concept cell culture experiments confirmed that mouse fibroblasts (NIH 3T3) and two different prostate cancer cell lines (22RV1, DU145) attached to and proliferated on zein foams. Conclusions/Significance We conducted screening and proof-of-concept experiments on the fabrication of foams from cereal-based bioplastics. We propose that a key indicator of foamability is the strain at break of the materials to be foamed (as calculated from stress vs. strain rate curves). Zein foams exhibit attractive properties (average pore size, pore size distribution, and porosity) for cell culture applications; we were able to establish and sustain mammalian cell cultures on zein

  18. Supercritical CO2 foaming of thermoplastic materials derived from maize: proof-of-concept use in mammalian cell culture applications.

    Directory of Open Access Journals (Sweden)

    Grissel Trujillo-de Santiago

    Full Text Available Foams are high porosity and low density materials. In nature, they are a common architecture. Some of their relevant technological applications include heat and sound insulation, lightweight materials, and tissue engineering scaffolds. Foams derived from natural polymers are particularly attractive for tissue culture due to their biodegradability and bio-compatibility. Here, the foaming potential of an extensive list of materials was assayed, including slabs elaborated from whole flour, the starch component only, or the protein fraction only of maize seeds.We used supercritical CO2 to produce foams from thermoplasticized maize derived materials. Polyethylene-glycol, sorbitol/glycerol, or urea/formamide were used as plasticizers. We report expansion ratios, porosities, average pore sizes, pore morphologies, and pore size distributions for these materials. High porosity foams were obtained from zein thermoplasticized with polyethylene glycol, and from starch thermoplasticized with urea/formamide. Zein foams had a higher porosity than starch foams (88% and 85%, respectively and a narrower and more evenly distributed pore size. Starch foams exhibited a wider span of pore sizes and a larger average pore size than zein (208.84 vs. 55.43 μm2, respectively. Proof-of-concept cell culture experiments confirmed that mouse fibroblasts (NIH 3T3 and two different prostate cancer cell lines (22RV1, DU145 attached to and proliferated on zein foams.We conducted screening and proof-of-concept experiments on the fabrication of foams from cereal-based bioplastics. We propose that a key indicator of foamability is the strain at break of the materials to be foamed (as calculated from stress vs. strain rate curves. Zein foams exhibit attractive properties (average pore size, pore size distribution, and porosity for cell culture applications; we were able to establish and sustain mammalian cell cultures on zein foams for extended time periods.

  19. Land Cover

    Data.gov (United States)

    Kansas Data Access and Support Center — The Land Cover database depicts 10 general land cover classes for the State of Kansas. The database was compiled from a digital classification of Landsat Thematic...

  20. Processing integral-skin polyolefin foams in single-charge rotational foam molding

    Science.gov (United States)

    Pop-Iliev, Remon

    This thesis focuses on establishing the scientific and engineering foundations for gaining a fundamental understanding of the mechanisms and critical parameters governing the processing of integral-skin low-density polyolefin foams in rotational foam molding. The presented research is particularly intended to broaden the knowledge in the field of manufacturing adjacent, but clearly distinct, layers of non-cellular and cellular structures, consisting of identical or compatible plastic grades, using a single-charge processing concept. Although this technology is beneficial for the efficacy of the molding process and the structural homogeneity of the moldings, its optimization raised a fairly large number of fundamental issues that had to be resolved through further research. In this context, an attempt has been made to establish rigorous, experimentally validated, theoretical models that describe the phenomena identified as the fundamental challenges of this technology. The major contributions of this thesis include: (i) optimization of the single-charge rotational foam molding process for the manufacture of both PE/PE and PE/PP integral-skin cellular composites, (ii) development of a two-step oven temperature profile that prevents the foamable resins invading the solid skin layer and ensures that skin formation always completes prior to the activation of the foamable resin, (iii) fundamental study of the adherence behavior of powders and foamable pellets to a high-temperature rotating mold wall, (iv) fundamental study of the lifespan of CBA-blown bubbles in non-pressurized non-isothermal polymer melts using hot-stage optical microscopy and digital imaging, (v) development of a detailed theoretical model involving diffusion, surface tension, and viscosity to simulate the observed foaming mechanism, and (vi) fundamental study of the rotofoamablility of polyolefin resins using both dry blending and melt compounding based methods and characterization of rheological and

  1. Relações hídricas e trocas gasosas em vinhedo sob cobertura plástica Water relations and leaf gas exchange in vineyard with plastic overhead cover

    Directory of Open Access Journals (Sweden)

    Geraldo Chavarria

    2008-12-01

    Full Text Available No presente estudo, determinaram-se as influências da cobertura plástica impermeável (CP sobre a demanda evaporativa atmosférica e o potencial da água no solo, bem como as conseqüências destas sobre as trocas gasosas foliares (fotossíntese, condutância estomática e transpiração e o potencial da água na folha da videira. As avaliações foram realizadas nos ciclos 2005/06 e 2006/07, em um vinhedo da cv. Moscato Giallo, conduzido em "Y", com cobertura plástica impermeável tipo ráfia (160 mm, em 12 fileiras com 35 m, deixando-se cinco fileiras sem cobertura (controle. Em ambas as áreas, avaliou-se o microclima quanto à temperatura do ar, umidade relativa do ar, radiação fotossinteticamente ativa e velocidade do vento, próximos ao dossel vegetativo. A CP aumentou a disponibilidade hídrica no solo nas entrelinhas e restringiu-a nas linhas, sobretudo em profundidades mais superficiais (0-10 cm. A CP também diminuiu a demanda evaporativa atmosférica, principalmente pela redução da velocidade do vento (-90%, aumentando o potencial da água na folha e a condutância estomática. De modo geral, a CP pode favorecer a condição hídrica e elevar a capacidade de assimilação de carbono em videiras.This study evaluated the plastic overhead cover (POC effect on evaporative demand of atmosphere and soil water content, as well as their consequences on gas exchange (photosynthesis, stomatal conductance and transpiration and leaf water potential in grapevine. The experiment was carried out during the 2005/06 and 2006/07 seasons, in a vineyard of 'Moscato Giallo', trained in "Y" and covered with an impermeable plastic cloth (2.65 m x 160 mm, in 12 rows with 35 m, with five rows left uncovered (control. In both areas, the microclimate was evaluated, in terms of air temperature, air relative humidity, radiation photosynthetically active and wind speed above the canopy. The POC increased the soil water content between rows and restricted it

  2. Surface modification of polypropylene based particle foams

    Science.gov (United States)

    Schreier, P.; Trassl, C.; Altstädt, V.

    2014-05-01

    This paper deals with the modification of the surface properties of expanded polypropylene (EPP). EPP is a semi-hard to soft elastic thermoplastic foam. The characteristic surface of EPP shows process-related steam nozzle imprints and gussets. Therefore EPP does not satisfy the quality requirements for visible automotive applications. In order to meet these demands, plastic surfaces are usually enhanced with functional or decorative coatings, e.g. textiles, plastic films or paint. The coating of plastics with low surface energies such as PP often leads to adhesion problems by reason of the missing polar and functional groups. This paper gives an evaluation of activation and pre-treatment methods of EPP, with the aim to identify the most suitable pre-treatment method. For this purpose five typical surface treatment methods - flame treatment, corona, fluorination, atmospheric and low-pressure plasma - were performed on EPP samples. As a comparison criterion the maximum increase in the adhesion force between a polyurethane-based coating and the modified EPP substrate was selected. Moreover the influence of the selected pre-treatment method on the increase in the total surface energy and its polar component was investigated by the drop shape analysis method. The results showed that the contact angle measurement is a suitable method to determine the polar and disperse fractions of the surface tension of EPP. Furthermore, all performed methods increased the adhesion of EPP.

  3. Development of fine-celled bio-fiber composite foams using physical blowing agents and nano-particles

    Science.gov (United States)

    Guo, Gangjian

    As one of eco-friendly bio-fibers, wood-fiber has been incorporated in plastics to make wood-fiber/plastic composites (WPC) with an increased stiffness, durability and lowered cost. However, these improvements are usually accompanied by loss in the ductility and impact strength of the composites. These shortcomings can be significantly improved by incorporating a fine-cell foam structure in the composites. This thesis presents the development of the foaming technology for the manufacture of fine-cell WPC foams with environmentally benign physical blowing agents (PBAs), and focuses on the elucidation of the fundamental foaming mechanisms and the related issues involved. One critical issue comes from the volatiles evolved from the wood-fiber during high temperature processing. The volatiles, as a blowing agent, can contribute to the foaming process. However, they lead to gross deterioration of the cell structure of WPC foams. The presence of volatiles makes foaming of WPC "a poorly understood black art". With the use of PBAs, a strategy of lowering processing temperature becomes feasible, to suppress the generation of volatiles. A series of PBA-based experiments were designed using a statistical design of experiments (DOE) technique, and were performed to establish the relationship of processing and material variables with the structure of WPC foams. Fundamental foaming behaviors for two different PBAs and two different polymer systems were identified. WPC foams with a fine-cell morphology and a desired density were successfully obtained at the optimized conditions. Another limitation for the wider application of WPC is their flammability. Innovative use of a small amount of nano-clay in WPC significantly improved the flame-retarding property of WPC, and the key issue was to achieve a high degree of exfoliation of nano-particles in the polymer matrix, to achieve a desired flammability reduction. The synergistic effects of nano-particles in foaming of WPC were

  4. Plastic Jellyfish.

    Science.gov (United States)

    Moseley, Christine

    2000-01-01

    Presents an environmental science activity designed to enhance students' awareness of the hazards of plastic waste for wildlife in aquatic environments. Discusses how students can take steps to reduce the effects of plastic waste. (WRM)

  5. 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.

  6. 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.

  7. Surface shear rheology of hydrophobin adsorption layers: laws of viscoelastic behaviour with applications to long-term foam stability

    NARCIS (Netherlands)

    Danov, K.D.; Radulova, G.M.; Kralchevsky, P.A.; Golemanov, K.; Stoyanov, S.D.

    2012-01-01

    The long-term stabilization of foams by proteins for food applications is related to the ability of proteins to form dense and mechanically strong adsorption layers that cover the bubbles in the foams. The hydrophobins represent a class of proteins that form adsorption layers of extraordinary high s

  8. Nanoscale patterns on micron-sized bubbles in foams

    Science.gov (United States)

    Dressaire, Emilie; Bell, David; Bee, Rodney; Lips, Alex; Stone, Howard

    2006-11-01

    The rheology and coarsening of foams is closely related to the microstructural characteristics of the small gas bubbles and their surface properties. We present experimental results of a foam formed upon shearing a mixture composed of glucose syrup and sucrose ester. Transmission Electron Microscopy reveals micron-size bubbles whose surfaces are fully covered with regular nanodimension, generally hexagonal, patterns. The influence of the shear rate during foam generation and the setting time on the development of the nanoscale patterns on the gas microcells are described. Plausible routes, driven by disproportionation of the gas from the small bubbles, for the formation of the nanoscale patterns are considered including a nucleation/crystallization pathway (Kim et al. 2003 Langmuir 19, p. 8455) and the buckling of an elastic insoluble surface film.

  9. 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.

  10. Drag coefficient for the air-sea exchange: foam impact in hurricane conditions

    CERN Document Server

    Golbraikh, Ephim

    2014-01-01

    A physical model is proposed for the estimation of the foam impact on the variation of the effective drag coefficient, C_d, with reference to the wind speed U10 in stormy and hurricane conditions. In the present model C_d is approximated by partitioning the sea surface into foam-covered and foam-free areas. Based on the available optical and radiometric measurements of the fractional foam coverage and the characteristic roughness of the sea-surface in the saturation limit of the foam coverage, the model yields the resulting dependence of C_d vs U10. This dependence is in fair agreement with that evaluated from field measurements of the vertical variation of the mean wind speed.

  11. Multiaxial yield surface of transversely isotropic foams: Part II—Experimental

    Science.gov (United States)

    Shafiq, Muhammad; Ayyagari, Ravi Sastri; Ehaab, Mohammad; Vural, Murat

    2015-03-01

    A robust understanding and modeling of the yield behavior in solid foams under complex stress states is essential to design and analysis of optimal structures using these lightweight materials. In pursuit of this objective a new custom-built Multi-Axial Testing Apparatus (MATA) is developed to probe the yield surface of transversely isotropic Divinycell H-100 PVC foam under a multitude of uniaxial, biaxial and triaxial strain paths. Experimental yield data produced constitutes the most comprehensive data set ever produced for any foam as it covers the entire spectrum of stress paths from hydrostatic compression to hydrostatic tension. Experimental results reveal that yielding in foams exhibits not only a quadratic pressure dependence, which is widely recognized in literature, but also a significant linear pressure dependence, which has been largely overlooked in previous studies. A new energy-based yield criterion developed for transversely isotropic foams is also validated using the experimental yield data.

  12. Effect of TiH2 on preparation of closed-cell aluminum foam and its compressive behavior

    Institute of Scientific and Technical Information of China (English)

    YANG Guo-jun; YU Hai-jun; YAO Guang-chun

    2006-01-01

    The vesicant problem during the process of preparing closed-cell aluminum foam by molten body transitional foaming process was discussed and the effect of granularity and addition of TiH2 on porosity of closed-cell aluminum foam was investigated.The static compressive behavior of closed-cell aluminum foam and the influence of porosity on static compressive property of closed-cell aluminum foam were researched as well. The results show that with increasing granularity of TiH2, the porosity of closed-cell aluminum foam firstly increases and then decreases gradually, the granularity should be controlled in the range of 38-74 μm which can result in higher porosity. The porosity of closed-cell aluminum foam increases with the increasing addition of TiH2,and the addition of TiH2 should be controlled from 1.5% to 2.5% which can result in homogeneous cell and moderate strength of closed-cell aluminum foam. The compressive process of closed-cell aluminum foam obviously displays linear elastic phase, plastic collapse phase, and densification phase, and the compressive strength grows with decreasing porosity.

  13. Modeling increasing effect of soil temperature through plastic film mulch in ground cover rice production system using CERES-Rice%基于CERES-Rice模型的覆膜旱作稻田增温效应模拟

    Institute of Scientific and Technical Information of China (English)

    马雯雯; 金欣欣; 石建初; 宁松瑞; 李森; 陶玥玥; 张亚男; 左强

    2015-01-01

    水稻覆膜旱作技术具有显著的节水、增温、防污和减排效应,是节水稻作技术体系的重要措施之一,将CERES-Rice模型用于覆膜旱作条件时,必须首先解决覆膜增温效应的准确模拟问题。该文拟应用热量传输理论及目前旱地作物生产系统中采用的覆膜增温效应模拟方法,来模拟水稻覆膜旱作生产体系中的增温效应,从而为完善 CERES-Rice 模型并使其能用于覆膜旱作水稻的生长模拟奠定基础。参数调校与模型检验验证通过2013、2014年在湖北房县开展的2 a水稻覆膜旱作田间试验来进行,共涉及淹水(对照)、覆膜湿润栽培和覆膜旱作共3个水分处理,分别对2个生长季、2个覆膜处理地表5 cm及地下10、20 cm处温度的变化过程进行了模拟,结果表明:经过参数调校后,所建立的覆膜增温模型可较好地模拟覆膜稻田地表和剖面上土壤温度的变化规律,地表5 cm处土壤温度模拟值与实测值的均方根差、相对均方根差分别低于1.8℃和10%,相关系数在0.89以上(P<0.01);尽管地下10、20 cm处的模拟误差稍大,也基本可满足要求,相应的均方根误差<3.2℃,相对均方根差<15%,相关系数>0.65(P<0.01)。%As one of the most promising water-saving rice production technologies, the ground cover rice production system (GCRPS) has been found to save water application, increase soil temperature, and reduce nitrogen pollution and methane emission. However, the feasibility of CERES-Rice, a software package widely and successfully applied in the traditional paddy rice production system (TPRPS), for simulating the rice growth in the GCRPS still remains unknown and needs further research. Undoubtedly, it should be based on accurately quantifying the effect of soil temperature enhancement caused by the ground cover material (chosen as the plastic film in this study). Therefore, the objective of

  14. Continuous microcellular foaming of polylactic acid/natural fiber composites

    Science.gov (United States)

    Diaz-Acosta, Carlos A.

    Poly(lactic acid) (PLA), a biodegradable thermoplastic derived from renewable resources, stands out as a substitute to petroleum-based plastics. In spite of its excellent properties, commercial applications are limited because PLA is more expensive and more brittle than traditional petroleum-based resins. PLA can be blended with cellulosic fibers to reduce material cost. However, the lowered cost comes at the expense of flexibility and impact strength, which can be enhanced through the production of microcellular structures in the composite. Microcellular foaming uses inert gases (e.g., carbon dioxide) as physical blowing agents to make cellular structures with bubble sizes of less than 10 microm and cell-population densities (number of bubbles per unit volume) greater than 109 cells/cm³. These unique characteristics result in a significant increase in toughness and elongation at break (ductility) compared with unfoamed parts because the presence of small bubbles can blunt the crack-tips increasing the energy needed to propagate the crack. Microcellular foams have been produced through a two step batch process. First, large amounts of gas are dissolved in the solid plastic under high pressure (sorption process) to form a single-phase solution. Second, a thermodynamic instability (sudden drop in solubility) triggers cell nucleation and growth as the gas diffuses out of the plastic. Batch production of microcellular PLA has addressed some of the drawbacks of PLA. Unfortunately, the batch foaming process is not likely to be implemented in the industrial production of foams because it is not cost-effective. This study investigated the continuous microcellular foaming process of PLA and PLA/wood-fiber composites. The effects of the processing temperature and material compositions on the melt viscosity, pressure drop rate, and cell-population density were examined in order to understand the nucleation mechanisms in neat and filled PLA foams. The results indicated that

  15. FOAM CONCRETE REINFORCEMENT BY BASALT FIBRES

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2012-10-01

    Full Text Available The authors demonstrate that the foam concrete performance can be improved by dispersed reinforcement, including methods that involve basalt fibres. They address the results of the foam concrete modeling technology and assess the importance of technology-related parameters. Reinforcement efficiency criteria are also provided in the article. Dispersed reinforcement improves the plasticity of the concrete mix and reduces the settlement crack formation rate. Conventional reinforcement that involves metal laths and rods demonstrates its limited application in the production of concrete used for thermal insulation and structural purposes. Dispersed reinforcement is preferable. This technology contemplates the infusion of fibres into porous mixes. Metal, polymeric, basalt and glass fibres are used as reinforcing components. It has been identified that products reinforced by polypropylene fibres demonstrate substantial abradability and deformability rates even under the influence of minor tensile stresses due to the low adhesion strength of polypropylene in the cement matrix. The objective of the research was to develop the type of polypropylene of D500 grade that would demonstrate the operating properties similar to those of Hebel and Ytong polypropylenes. Dispersed reinforcement was performed by the basalt fibre. This project contemplates an autoclave-free technology to optimize the consumption of electricity. Dispersed reinforcement is aimed at the reduction of the block settlement in the course of hardening at early stages of their operation, the improvement of their strength and other operating properties. Reduction in the humidity rate of the mix is based on the plasticizing properties of fibres, as well as the application of the dry mineralization method. Selection of optimal parameters of the process-related technology was performed with the help of G-BAT-2011 Software, developed at Moscow State University of Civil Engineering. The authors also

  16. Caracterização fenológica e requerimento térmico da cultivar moscato giallo sob cobertura plástica Phenological characterization and thermal requirement of moscato giallo cultivar under plastic cover

    Directory of Open Access Journals (Sweden)

    Geraldo Chavarria

    2009-03-01

    Full Text Available Os efeitos da cobertura plástica (CP sobre a fenologia e o requerimento térmico da Vitis vinifera L. 'Moscato Giallo' foram estudados em dois ciclos (2005/2006 e 2006/2007. Determinou-se a duração média dos principais períodos fenológicos por meio de avaliações semanais, desde a poda até a queda das folhas. O somatório térmico em graus-dia acumulados (GD foi calculado considerando-se a temperatura-base de 10ºC, e medidas da temperatura do ar máxima e mínima ao longo de todo o ciclo, nas áreas coberta e descoberta (testemunha. A cobertura plástica aumentou o somatório térmico e antecipou o início da brotação, reduzindo a duração das etapas fenológicas da poda até a mudança de cor das bagas. Entretanto, a redução da radiação fotossinteticamente ativa (RFA proporcionada pela cobertura plástica atrasou, em média, 18 dias o processo de maturação das uvas da cultivar Moscato Giallo. A soma térmica acumulada (poda até colheita das áreas coberta e descoberta foi, respectivamente, 2.079 e 1.847 GD no primeiro ciclo, e 1.864 e 1.640 GD no segundo ciclo. A cobertura plástica exige uma alteração nas práticas culturais, como a necessidade de poda verde para reduzir os efeitos da restrição de RFA e o atraso na data de colheita, em relação ao cultivo convencional, em função da menor taxa de evolução da maturação sob a cobertura.The plastic overhead cover (POC effects on phenology and thermal requirement of grapevine Vitis vinifera L. 'Moscato Giallo' were evaluated in two seasons (2005/2006 and 2006/2007. The phenology was weekly determined since the winter pruning until the falling of the leaves. The thermal requirement as degree-days (GDºC was calculated in the same period using 10ºC as base temperature and measured of maximal and minimal air temperature throughout both cycles in covered and uncovered areas. POC increased the thermal sum and it anticipated the budburst and decreased the duration of

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-29

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

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

    Science.gov (United States)

    Setyawan, Paryanto Dwi; Sugiman, Saputra, Yudhi

    2016-03-01

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

  19. 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.

  20. 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.

  1. Extensional Flow Properties of Externally Plasticized Cellulose Acetate: Influence of Plasticizer Content

    Directory of Open Access Journals (Sweden)

    Hans-Joachim Radusch

    2013-07-01

    Full Text Available Elongational flow properties of polymer melts are very important for numerous polymer processing technologies such as blown film extrusion or foam extrusion. Rheotens tests were conducted to investigate the influence of plasticizer content on elongational flow properties of cellulose acetate (CA. Triethyl citrate (TEC was used as plasticizer. Melt strength decreases whereas melt extensibility increases with increasing plasticizer content. Melt strength was further studied as a function of zero shear viscosity. The typical draw resonance of the Rheotens curve shifts to higher drawdown velocity and the amplitude of the draw resonance decreases with increasing TEC content. With respect to foam extrusion, not only are melt strength and melt extensibility important but the elongational behavior at low strain rates and the area under the Rheotens curve are also significant. Therefore, elongational viscosity as well as specific energy input were calculated and investigated with respect to plasticizer content. Preliminary foam extrusion tests of externally plasticized CA using chemical blowing agents confirm the results from rheological characterization.

  2. Mechanical characterization of the role of defects in sintered FeCrAIY foams

    Institute of Scientific and Technical Information of China (English)

    M. Kepets; T. J. Lu; A. P. Dowling

    2007-01-01

    Open celled metal foams fabricated through metal sintering are a new class of material that offers novel mechanical and acoustic properties. Previously, polymer foams have been widely used as a means of absorbing acous-tic energy. However, the structural applications of these foams are limited. The metal sintering approach offers a cost-effective means for the mass-production of open-cell foams from a range of materials, including high-temperature steel alloys. In this first part of two-paper series, the mechanical properties of open-celled steel alloy (FeCrAlY) foams were characterized under uniaxial compression and shear loading.Compared to predictions from established models, a signi-ficant knockdown in material properties was observed. This knockdown was attributed to the presence of defects throu-ghout the microstructure that result from the unique fabri-cation process. Further in situ tests were carded out in a SEM (scanning electronic microscope) in order to investigate the effects of defects on the properties of the foams. Typi-cally, the onset of plastic yielding was observed to occur at defect locations within the microstructure. At lower relative densities, ligament bending dominates, with the deformation initializing at defects. At higher relative densities, an additional deformation mechanism associated with mem-brane elements was observed. In the follow-up of this paper,a finite element model will be constructed to quantify the effects of defects on the mechanical performance of the open-cell foam.

  3. Nonlinear mechanics of hyper elastic polyurethane furniture foams

    Directory of Open Access Journals (Sweden)

    Jerzy Smardzewski

    2008-07-01

    Full Text Available Upholstered furniture intended to provide better sleep and rest, especially furniture for disabled persons, require careful design of elastic spring systems. In the majority of cases, when designing new articles, both furniture designers and manufacturers rely on long-term experience and craftsman’s intuition. On the other hand, the accumulated interdisciplinary knowledge of modern medical laboratories as well as furniture certification offices indicate that it is necessary to carry out investigations related to the mechanical properties of raw materials used to manufacture furniture and to conduct virtual modelling of the phenomena connected with the contact of the human body with the elastic base. The aim of this study was to determine the elastic properties of hyper-plastic polyurethane foams applied in furniture industry, to elaborate mathematical models of these materials on the basis of non-linear Mooney-Rivlin models and to conduct a non-linear numerical analysis of contact strains in a deformed seat made of polyurethane foam. The results of the experiments revealed that the mechanical properties of polyurethanefoams are described properly by the Mooney-Rivlin model. Knowing the mechanical properties of these foams, it is possible to create freely complex furniture elastic systems. The state of strains in the contact of the human body with foam depends on the friction between these bodies. Therefore, in practice, it is advisable to design seatsystems resulting in minimal frictions between the user’s clothes and the furniture seat.

  4. A new design of foam spray nozzle used for precise dust control in underground coal mines

    Institute of Scientific and Technical Information of China (English)

    Han Fangwei; Wang Deming; Jiang Jiaxing; Zhu Xiaolong

    2016-01-01

    In order to improve the utilization rate of foam, an arc jet nozzle was designed for precise dust control. Through theoretical analysis, the different demands of foam were compared amongst arc jets, flat jets and full cone jets when the dust source was covered identically by foam. It is proved that foam consumption was least when an arc jet was used. Foam production capability of an arc jet nozzle under different con-ditions was investigated through experiments. The results show that with the gas liquid ratio (GLR) increasing, the spray state of an arc jet nozzle presents successively water jet, foam jet and mist. Under a reasonable working condition range of foam production and a fixed GLR, foam production quan-tity increases at first, and then decreases with the increase of liquid supply quantity. When the inner diameter of the nozzle is 14 mm, the best GLR is 30 and the optimum liquid supply quantity is 0.375 m3/h. The results of field experiments show that the total dust and respirable dust suppression effi-ciency of arc jet nozzles is 85.8%and 82.6%respectively, which are 1.39 and 1.37 times higher than the full cone nozzles and 1.20 and 1.19 times higher than the flat nozzles.

  5. Properties of foam and composite materials made o starch and cellulose fiber

    Science.gov (United States)

    Composite materials were made of starch and cellulose fibers. Pre-gelatinized starch was effective in dispersing pulp fiber in a starch matrix to form a viscous starch/fiber dough. The starch/fiber dough was a useful feedstock for various composite foam and plastic materials. Viscous blends of star...

  6. Economical and Ecological Fesasibility of Plastic Recycling

    OpenAIRE

    Hirschpold, Andrew; Juctye, Kristina; Renzhong, Jiang; Debin, LIU; Varona, Hector P.; Kevelaitis, Karolis

    2005-01-01

    #Group 3 International Nat Bas Economical and Ecological Feasibility of Plastic Recycling Abstract This project is carried out as the final project for the first semester of Bachelor of Science studies. Our project will aim on plastic recycling. Plastic is a manmade material which covers a range of synthetic or semi-synthetic products made thru polymerization. The development of plastic products has accompanied the development of human’s history since it was invented while they ...

  7. Economical and Ecological Fesasibility of Plastic Recycling

    OpenAIRE

    Hirschpold, Andrew; Juctye, Kristina; Renzhong, Jiang; Debin, Liu; Varona, Hector P.; Kevelaitis, Karolis

    2005-01-01

    #Group 3 International Nat Bas Economical and Ecological Feasibility of Plastic Recycling Abstract This project is carried out as the final project for the first semester of Bachelor of Science studies. Our project will aim on plastic recycling. Plastic is a manmade material which covers a range of synthetic or semi-synthetic products made thru polymerization. The development of plastic products has accompanied the development of human’s history since it was invented while they ...

  8. INVESTIGATION ON THE MECHANICAL AND MORPHOLOGICAL PROPERTIES OF FOAMED NANOCOMPOSITES BASED ON WOOD FLOUR/PVC/MULTI-WALLED CARBON NANOTUBE

    Directory of Open Access Journals (Sweden)

    Afshin Tavassoli Farsheh

    2011-02-01

    Full Text Available Recently, the use of nanoparticles in Wood Plastic Composites (WPCs has been considered by researchers. In this study, Multi-Walled Carbon Nanotubes (MWCNTs were compounded with PVC, wood-flour, and foaming agent in an internal mixer. The wood flour amount was constant at 40 phr. For CNT and chemical foaming agent , different levels of 0, 1, 2 phr and 0, 3, 6 phr were considered respectively. The samples were foamed via batch process using a compression molding machine at 180°C. Morphology, density, water absorption, thickness swelling, and tensile properties of foamed composites were evaluated as a function of CNT and chemical foaming agent contents. The experimental results indicated that in the presence of CNT, cell density increased and cell size decreased. Density of the foamed composites was not affected by chemical foaming agent contents. Water absorption and thickness swelling of samples were decreased as compared with wood plastic composite without CNTs. Also, the maximum tensile strength and modulus were increased by up to 20% and 23% respectively

  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. 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.

  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. 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.

  18. 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.

  19. 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.

  20. Reflectivity and Emissivity of Sea Foam at L-band

    Science.gov (United States)

    Anguelova, M. D.; Burrage, D. M.; Bettenhausen, M. H.

    2015-12-01

    The ubiquitous use of the Global Positioning System (GPS) for navigation is well known. GPS operates at L-band frequencies of 1-2 GHz. Because these low microwave frequencies penetrate clouds and rain, GPS signals can detect the specular reflection and diffuse scattering from flat and rough surfaces. This makes the GPS signals useful for geophysical measurements in all weather conditions. Aircraft and satellite-borne GPS reflectometers have been shown to successfully sense ocean surface wind. L-band reflectometry measures changes in ocean surface reflectivity due to changes of ocean surface roughness as wind increases. The use of GPS, together with other Global Navigation Satellite Systems, will soon provide hundreds of L-band transmitters in space and thus high temporal resolution for geophysical measurements. With its all weather capability and high temporal resolution, GPS reflectometry can provide wind speed data in hurricane conditions. Such capabilities enable the new Cyclone Global Navigation Satellite System (CYGNSS) project which aims to improve the skill of hurricane intensity forecasts. However, wave breaking under high winds produces sea foam (whitecaps) and sea spray, which complicate processes acting at the air-sea interface. Whitecaps and sea spray have high emissivity at L-band and will thus reduce the ocean reflectivity needed for wind speed retrieval. A combination of L-band reflectometry and L-band radiometry can thus help to better understand and model the physical mechanisms governing the L-band sensor responses. We use a radiative transfer model formulated in terms of foam layer thickness and void fraction to evaluate both the reflectivity and emissivity of a foam-covered sea surface. We report on the attenuation of L-band radiation in foam layers, and the corresponding foam reflectivity, for layers with varying thicknesses and void fractions. The reflected GPS signal sensitivity to wind speed variations in the presence of foam is assessed.

  1. Benthic Cover

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic cover (habitat) maps are derived from aerial imagery, underwater photos, acoustic surveys, and data gathered from sediment samples. Shallow to moderate-depth...

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

    Science.gov (United States)

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

    2013-11-11

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

  3. Plastics Technology.

    Science.gov (United States)

    Barker, Tommy G.

    This curriculum guide is designed to assist junior high schools industrial arts teachers in planning new courses and revising existing courses in plastics technology. Addressed in the individual units of the guide are the following topics: introduction to production technology; history and development of plastics; safety; youth leadership,…

  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. Comments on "Cahill's Quantum Foam Inflow Theory of Gravity"

    CERN Document Server

    Martin, T D

    2004-01-01

    We reveal an underlying flaw in Reginald T. Cahill's recently promoted quantum foam inflow theory of gravity. It appears to arise from a confusion of the idea of the Galilean invariance of the acceleration of an individual flow with what is obtained as an acceleration when a homogeneous flow is superposed with an inhomogeneous flow. We also point out that the General Relativistic covering theory he creates by substituting a generalized Painleve-Gullstrand metric into Einstein's field equations leads to absurd results.

  10. Catalytic thermal cracking of post-consumer waste plastics to fuels: Part 1 - Kinetics and optimization

    Science.gov (United States)

    Thermogravimetric analysis (TGA) was used to investigate thermal and catalytic pyrolysis of waste plastics such as prescription bottles (polypropylene/PP), high density polyethylene, landfill liners (polyethylene/PE), packing materials (polystyrene/PS), and foams (polyurethane/PU) into crude plastic...

  11. 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.

  12. 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.

  13. 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

  14. Fire performance of LNG carriers insulated with polystyrene foam.

    Science.gov (United States)

    Havens, Jerry; Venart, James

    2008-10-30

    Analysis of the response of a liquid-full Moss Sphere LNG tank insulated with polystyrene foam to an engulfing LNG fire indicates that current regulatory requirements for pressure relief capacity sufficient to prevent tank rupture are inadequate. The inadequacy of the current requirements stems primarily from two factors. Firstly, the area of the Moss Sphere protruding above what would be the nominal deck on a conventional carrier, which is protected only by a steel weather cover from exposure to heat from a tank-engulfing fire, is being underestimated. Secondly, aluminum foil-covered polystyrene foam insulation applied to the exterior of the LNG tank is protected above the deck only by the steel weather cover under which the insulation could begin to melt in as little as 1-3 min, and could completely liquefy in as few as 10 min. U.S. and International Regulations require that the insulations on the above-deck portion of tanks have approved fire proofing and stability under fire exposure. Polystyrene foam, as currently installed on LNG carriers, does not appear to meet these criteria. As a result of these findings, but giving no consideration to the significant potential for further damage if the polystyrene should burn, the boil-off rate is predicted to be an order-of-magnitude higher than provided for by current PRV sizing requirements.

  15. 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.

  16. Effects of plastic covering methods on the growth and yield of potatoes in winter fallow rice fields in Hunan%覆膜方式对湖南冬种马铃薯生长与产量的影响

    Institute of Scientific and Technical Information of China (English)

    胡新喜; 刘明月; 何长征; 宋勇; 蒋凌红; 熊兴耀

    2013-01-01

    以‘费乌瑞它’马铃薯为试验材料,在冬闲稻田进行地膜覆盖、小拱棚覆盖、双膜覆盖(膜覆盖+小拱棚覆盖)和裸地等栽培田间比较试验.结果表明:双膜覆盖的增温效果最好,出苗期内其平均土壤温度分别比小拱棚覆盖、地膜覆盖和裸地栽培高0.33、1.93、2.89℃;双膜覆盖栽培的马铃薯出苗最早,分别比小拱棚覆盖、地膜覆盖、裸地栽培的提早4、21、31 d;覆膜处理的马铃薯植株株高均显著高于裸地栽培,但茎粗和主茎数均显著低于裸地栽培;双膜覆盖栽培马铃薯的总产量和商品薯产量最高,分别为31.18、28.54t/hm2,小拱棚覆盖和地膜覆盖栽培次之,覆盖处理的总产量和商品薯产量均显著高于裸地栽培;双膜覆盖栽培的效益最好,为1.222万元/hm2.%Favorita,a breed of potato was selected as a test material to compare its growth and yield under four different cultivation circumstances in winter fallow rice fields,they are plastic mulching,arch plastic mulching,plastic mulching plus arch plastic mulching (also called double films mulching) and non-mulching.The results showed that the daily average soil temperature with double films mulching was highest,higher than that of plastic mulching,arch plastic mulching and non-mulching 0.33,1.93,2.89 ℃,respectively.Therefore,potatoes cultivated with double films mulching was the first one in seedling sprout,which was earlier 4,21,31 d than those of cultivated with plastic mulching,arch plastic mulching and non-mulching,respectively.Although the plant height of potatoes cultivated with plastic mulching was higher than that of potatoes cultivated with non-mulching significantly,the stem diameter and main stem number were significantly less than that of potatoes cultivated in non-mulching.Double films mulching cultivation could improve total yield and market needed tuber yield,with 31.18 and 28.54 ton per hectare respectively.And the next were

  17. Development of Expanded Thermoplastic Polyurethane Bead Foams and Their Sintering Mechanism

    Science.gov (United States)

    Hossieny, Nemat

    Polymer bead foaming technology represents a breakthrough in the production of low density plastic foamed components that have a complex geometrical structure and has helped to expand the market for plastic foams by broadening their applications. In this research, the unique microstructure of thermoplastic polyurethane (TPU) consisting of phase-separated hard segment (HS) domains dispersed in the soft segment (SS) matrix has been utilized to develop expanded TPU (E-TPU) bead foam with microcellular morphologies and also to create inter-bead sintering into three dimensional products using steam-chest molding machine. The phase-separation and crystallization behavior of the HS chains in the TPU microstructure was systematically studied in the presence of dissolved gases and also by changing the microstructure of TPU by melt-processing and addition of nano-/micro-sized additives. It was observed that the presence of gas improved the phase separation (i.e. crystallization) of HSs and increased the overall crystallinity of the TPU. It was also shown that by utilizing the HS crystalline domains, the overall foaming behavior of TPU (i.e. cell nucleation and expansion ratio) can be significantly improved. Moreover, the HS crystalline domains can be effective for both sintering of the beads as well strengthening the individual beads to improve the property of the moulded part. It was also observed that unlike other polymer bead foaming technologies, the E-TPU bead foaming sintering does not require formation of double melting-peak. The original broad melting peak existing in the TPU microstructure due to the wide size distribution of HS crystallites can be effectively utilized for the purpose of sintering as well as maintenance of the overall dimensional stability of the moulded part.

  18. Dynamic and Thermal Properties of Aluminum Alloy A356/Silicon Carbide Hollow Particle Syntactic Foams

    Directory of Open Access Journals (Sweden)

    James Cox

    2014-12-01

    Full Text Available Aluminum alloy A356 matrix syntactic foams filled with SiC hollow particles (SiCHP are studied in the present work. Two compositions of syntactic foams are studied for quasi-static and high strain rate compression. In addition, dynamic mechanical analysis is conducted to study the temperature dependent energy dissipation and damping capabilities of these materials. The thermal characterization includes study of the coefficient of thermal expansion (CTE. A356/SiCHP syntactic foams are not strain rate sensitive as the compressive strength displayed little variation between the tested strain rates of 0.001–2100 s−1. Microscopic analysis of the high strain rate compression tested specimens showed that the fracture is initiated by the failure of hollow particles at the onset of the plastic deformation region. This is followed by plastic deformation of the matrix material and further crushing of particles. The syntactic foams showed decrease in storage modulus with increasing temperature and the trend was nearly linear up to 500 °C. The alloy shows a similar behavior at low temperature but the decrease in storage modulus increases sharply over 375 °C. The loss modulus is very small for the tested materials because of lack of viscoelasticity in metallic materials. The trend in the loss modulus is opposite, where the matrix alloy has lower loss modulus than syntactic foams at low temperature. However, over 250 °C the matrix loss modulus starts to increase rapidly and attains a peak around 460 °C. Syntactic foams have higher damping parameter at low temperatures than the matrix alloy. Incorporation of SiCHP helps in decreasing CTE. Compared to the CTE of the matrix alloy, 23.4 × 10−6 °C−1, syntactic foams showed CTE values as low as 11.67 × 10−6 °C−1.

  19. 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.

  20. Cell-structure and mechanical properties of closed-cell aluminum foam

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yun(周芸); ZUO Xiao-qing(左孝青); SUN Jia-lin(孙加林); S.R.Nutt

    2004-01-01

    The density, cell size and structure of closed-cell aluminum foam were measured by optical microscopy and image analysis. The properties and the mechanism of compressive deformation that occur in closed-cell aluminum foam were measured and discussed. The results show that the cell size of foam with density of 0.37 mg/m3 is distributed in the range of 0.5 - 4.0 mm. The cell size of foam with density of 0.33 mg/m3 is distributed in the range of 0.5 - 5.0 mm. The cell wall thickness of both types is 0.1 - 0.3 mm. The closed-cell aluminum foam almost belongs to isotropic one, with a variation of ±15% in elastic modulus and yield strength in longitudinal and transverse direction. Under compressive loading, foam materials show inhomogeneous macroscopic deformation. The site of the onset of local plastic deformation depends on the cell structure. The shape of cell is more important than size in determining the yielding susceptibility of the cells. At early stage of deformation,the deformation is localized in narrow bands having width of one cell's diameter, and outside the bands the cell still remains the original shape. The cells within bands experience large permanent deformation. The band normals are usually within 20° of the loading axis.

  1. Multiaxial yield surface of transversely isotropic foams: Part I-Modeling

    Science.gov (United States)

    Ayyagari, Ravi Sastri; Vural, Murat

    2015-01-01

    A new yield criterion is proposed for transversely isotropic solid foams. Its derivation is based on the hypothesis that the yielding in foams is driven by the total strain energy density, rather than a completely phenomenological approach. This allows defining the yield surface with minimal number of parameters and does not require complex experiments. The general framework used leads to the introduction of new scalar measures of stress and strain (characteristic stress and strain) for transversely isotropic foams. Furthermore, the central hypothesis that the total strain energy density drives yielding in foams ascribes to the characteristic stress an analogous role of von Mises stress in metal plasticity. Unlike the overwhelming majority of yield models in literature the proposed model recognizes the tension-compression difference in yield behavior of foams through a linear mean stress term. Predictions of the proposed yield model are in excellent agreement with the results of uniaxial, biaxial and triaxial FE analyses implemented on both isotropic and transversely isotropic Kelvin foam models.

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

    Science.gov (United States)

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

    2016-05-01

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

  3. Plasticity and beyond microstructures, crystal-plasticity and phase transitions

    CERN Document Server

    Hackl, Klaus

    2014-01-01

    The book presents the latest findings in experimental plasticity, crystal plasticity, phase transitions, advanced mathematical modeling of finite plasticity and multi-scale modeling. The associated algorithmic treatment is mainly based on finite element formulations for standard (local approach) as well as for non-standard (non-local approach) continua and for pure macroscopic as well as for directly coupled two-scale boundary value problems. Applications in the area of material design/processing are covered, ranging from grain boundary effects in polycrystals and phase transitions to deep-drawing of multiphase steels by directly taking into account random microstructures.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. 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.

  12. 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...

  13. Plastic bronchitis

    National Research Council Canada - National Science Library

    Singhi, Anil Kumar; Vinoth, Bharathi; Kuruvilla, Sarah; Sivakumar, Kothandam

    2015-01-01

    Plastic bronchitis, a rare but serious clinical condition, commonly seen after Fontan surgeries in children, may be a manifestation of suboptimal adaptation to the cavopulmonary circulation with unfavorable hemodynamics...

  14. 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.

  15. 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....

  16. 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

  17. 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

  18. Plastic Fishes

    CERN Multimedia

    Trettnak, Wolfgang

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness. The slideshow below gives you a taste of the artworks by Wolfgang Trettnak and Margarita Cimadevila.

  19. Plastic Bridge

    Institute of Scientific and Technical Information of China (English)

    履之

    1994-01-01

    Already ubiquitous in homes and cars, plastic is now appearing inbridges. An academic-industrial consortium based at the University ofCalifornia in San Diego is launching a three-year research program aimed atdeveloping the world’s first plastic highway bridge, a 450-foot span madeentirely from glass-,carbon,and polymer-fiber-reinforced composite mate-rials, the stuff of military aircraft. It will cross Interstate 5 to connect thetwo sides of the school’s campus.

  20. 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.

  1. 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.

  2. Three-dimensional thermal aging and dimensional stability of cellular plastic insulation

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Youchen; Kokko, E. [VTT Building Technology, Espoo (Finland). Building Physics, Puilding Services and Fire Technology

    1996-12-31

    The requirement of producing environmental-friendly plastic foam results in the replacement of the traditional blowing agents, CFCs (chlorofluorocarbons), with zero ozone depletion potential (ODP) alternatives. The tool which is able to evaluate the quality of the new generation of plastic foams becomes practically important. A 3-dimensional (3-D) heat and mass (gases) transfer model with respect to rigid closed-cell cellular plastics has been carefully deduced and furnished based on our previous understanding of such problems. To solve the 3-D parabolic partial differential equations subject to the third type of boundary conditions, a modified alternative direction implicit (AD I) finite difference method was developed by using the natural laws. To predict the long-term dimensional stability of a plastic foam insulation in air, a simplified mechanical model has been presented. In addition, to closure the prediction of foam dimensional stability, we have deduced a general relationship between the elastic modulus (Young`s modulus) of a rigid closed-cell cellular plastic, E{sub f} and its density, {phi}{sub p}. In comparison to the published measurements and other two well-known E{sub f} - {phi}{sub p} models, it is found that our E{sub f} - up relationship gives better prediction and is valid over the entire rigid plastic foam density range. Thermal aging and average volume change of zero ODP foams with different facing will be addressed. In addition, the application of the model shows the effects of foam dimension and facing on its thermal aging and deformation. (orig.) (13 refs.)

  3. High Strain Rate Compressive Behavior of Polyurethane Resin and Polyurethane/Al2O3 Hollow Sphere Syntactic Foams

    Directory of Open Access Journals (Sweden)

    Dung D. Luong

    2014-01-01

    Full Text Available Polyurethane resins and foams are finding extensive applications. Seat cushions and covers in automobiles are examples of these materials. In the present work, hollow alumina particles are used as fillers in polyurethane resin to develop closed-cell syntactic foams. The fabricated syntactic foams are tested for compressive properties at quasistatic and high strain rates. Strain rate sensitivity is an important concern for automotive applications due to the possibility of crash at high speeds. Both the polyurethane resin and the syntactic foam show strain rate sensitivity in compressive strength. It is observed that the compressive strength increases with strain rate. The energy absorbed up to 10% strain in the quasistatic regime is 400% higher for the syntactic foam in comparison to that of neat resin at the same strain rate.

  4. [Obtainment of pineapple juice powder by foam-mat drying].

    Science.gov (United States)

    Beristain, C I; Cortés, R; Casillas, M A; Díaz, R

    1991-06-01

    The foam-mat production and stability using pineapple juice concentrate (25, 30 and 40 degrees Brix), adding a surfactants mixture and maltodextrin (DE 10) as co-adjuvant, stirred in a commercial mixer, was studied. Adequate foam formation conditions were as follows: concentrate of 25 degrees Brix using surface active agents (Sorbac 60-Polisorbac 80) 0.285% surface active agent/total solids, HLB = 6, and stirring time, 7 min. The foam was dehydrated in an oven dried with a horizontal air flow circulation set at 60, 70 and 80 degrees C using 3, 5 and 10 mm bed depths. The best conditions were obtained at 60 degrees C and 5 mm bed depth. The product had a particle size of sieve 40-80, and a moisture content of 3%. It was then packaged in multilayer plastic film and stored at environmental conditions. No brown color formation or mold growth was detected during storage. Pineapple juice and a refreshing drink were prepared. The general acceptability in a community indicated that 95% of the population involved accepted the product.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. GREEN PLASTIC: A NEW PLASTIC FOR PACKAGING

    OpenAIRE

    Mr. Pankaj Kumar*, Sonia

    2016-01-01

    This paper gives a brief idea about a new type of plastic called as bio-plastic or green plastic. Plastic is used as a packaging material for various products, but this plastic is made up of non renewable raw materials. There are various disadvantages of using conventional plastic like littering, CO2 production, non-degradable in nature etc. To overcome these problems a new type of plastic is discovered called bio-plastic or green plastic. Bio-plastic is made from renewable resources and also...

  11. The plastic-associated microorganisms of the North Pacific Gyre.

    Science.gov (United States)

    Carson, Henry S; Nerheim, Magnus S; Carroll, Katherine A; Eriksen, Marcus

    2013-10-15

    Microorganisms likely mediate processes affecting the fate and impacts of marine plastic pollution, including degradation, chemical adsorption, and colonization or ingestion by macroorganisms. We investigated the relationship between plastic-associated microorganism communities and factors such as location, temperature, salinity, plankton abundance, plastic concentration, item size, surface roughness, and polymer type. Small plastic items from the surface of the North Pacific Gyre in 2011 were examined using scanning electron microscopy. Bacillus bacteria (mean 1664 ± 247 individuals mm(-2)) and pennate diatoms (1097 ± 154 mm(-2)) were most abundant, with coccoid bacteria, centric diatoms, dinoflagellates, coccolithophores, and radiolarians present. Bacterial abundance was patchy, but increased on foamed polystyrene. Diatom abundance increased on items with rough surfaces and at sites with high plastic concentrations. Morphotype richness increased slightly on larger fragments, and a biogeographic transition occurred between pennate diatom groups. Better characterizing this community will aid in understanding how it interacts with plastic pollution.

  12. 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...

  13. 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

  14. 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.

  15. 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.

  16. Histopathological reaction over prosthesis surface covered with silicone and polyurethane foam implanted in rats Reação histopatológica sobre a superfície de próteses cobertas por espuma de silicone e poliuretano implantadas em ratos

    Directory of Open Access Journals (Sweden)

    Jorge Wagenführ-Júnior

    2012-12-01

    Full Text Available PURPOSES: To evaluate whether polyurethane foam leads more intense foreign-body reaction than silicone foam. To compare the vascularization of the capsules surrounding the foam implants. To investigate if the capsule of polyurethane foam implanted has greater amount of collagen than that of silicone foam. METHODS: Sixty-four young male Wistar rats were allocated into two groups: polyurethane foam and silicone foam. Subcutaneous discs were implanted into the dorsum of the animals in both groups. The capsules were assessed 28 days, two months, three months and six months postoperatively. Microscopic analysis with H&E stain was performed to evaluate the acute and chronic inflammatory process, foreign-body reaction and neovascularization. The analysis with picrosirius red was performed using the ImageProPlus software, to measure the number of vessels and collagen types I and III. RESULTS: There were no statistical differences between the two groups regarding the acute and chronic inflammatory processes. All rats from the polyurethane group, in all times, exhibited moderate or intense foreign-body reaction, with statistic significant difference (p=0.046 when compared with the silicone group, in which the reaction was either mild or nonexistent at two months. Vascular proliferation was significantly different between the groups at 28 days (p=0.0002, with the polyurethane group displaying greater neovascularization with H&E stain. Similar results were obtained with picrosirius red, which revealed in the polyurethane group a much greater number of vessels than in the silicone group (p=0.001. The collagen area was larger in the polyurethane group, significantly at 28 days (p=0.001 and at two months (p=0.030. CONCLUSIONS: Polyurethane foam elicited more intense foreign-body reaction when compared with silicone foam. The number of vessels was higher in the capsules of the polyurethane foam implants 28 days after the operation. The capsule of the

  17. Managing cover crops on strawberry furrow bottoms

    Science.gov (United States)

    Bare furrows in strawberry fields with plastic mulch covered beds can lead to lots of soil erosion and runoff during winter rainy periods. This article describes how growers can plant and manage cover crops in these furrows to minimize runoff and soil erosion. This is based on on-going research at...

  18. 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.

  19. 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.

  20. 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...

  1. Properties of 30 lb/ft{sup 3} rigid polyurethane foams

    Energy Technology Data Exchange (ETDEWEB)

    Wenski. E.G. [Allied Signal Federal Manufacturing and Technologies, Kansas City, MO (United States); Stinebaugh, R.E.; York, A.R. II [Sandia National Labs., Albuquerque, NM (United States)

    1997-03-01

    This report summarizes tests on five different foams. Two are manufactured at Allied Signal, two at North Carolina Foam Industries, and one at General Plastics. The tests conducted are: thermal conductivity at various temperatures, specific heat at 60{degrees}C, compressive strength at ambient and 60{degrees}C, thermogravimetric analysis to 800{degrees}C, intumescence, and char formation properties. A CHN analysis was also performed. Funding for the testing of rigid polyurethane foams originated from the AT-400A container program at Sandia National Laboratories. This testing supported the development of the AT-400A container. The AT-400A is a storage and transportation container that will be used initially at the Pantex Plant for storage of plutonium from dismantled nuclear weapons.

  2. Investigation on the foaming behaviors of NC-based gun propellants

    Directory of Open Access Journals (Sweden)

    Yu-xiang Li

    2014-09-01

    Full Text Available To prepare the porous NC-based (nitrocellulose-based gun propellants, the batch foaming process of using supercritical CO2 as the physical blowing agent is used. The solubilities of CO2 in the single-base propellants and TEGDN (trimethyleneglycol dinitrate propellants are measured by the gravimetric method, and SEM (scanning electron microscope is used to observe the morphology of foamed propellants. The result shows that a large amount of CO2 could be dissolved in NC-based propellants. The experimental results also reveal that the energetic plasticizer TEGDN exerts an important influence on the pore structure. The triaxial tensile failure mechanism for solid-state nucleation is used to explain the nucleation of NC-based propellants in the solid state. Since some specific foaming behaviors of NC-based propellants can not be explained by the failure mechanism, a solid-state nucleation mechanism which revises the triaxial tensile failure mechanism is proposed and discussed.

  3. 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....

  4. 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.

  5. "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.

  6. 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

  7. 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.

  8. Surface conductivity measurements in nanometric to micrometric foam films.

    Science.gov (United States)

    Bonhomme, Oriane; Mounier, Anne; Simon, Gilles; Biance, Anne-Laure

    2015-05-20

    Foam films (a liquid lamella in air covered by surfactants) are tools of choice for nanofluidic characterization as they are intrinsically nanometric. Their size is indeed fixed by a balance between external pressure and particular molecular interactions in the vicinity of interfaces. To probe the exact nature of these interfaces, different characterizations can be performed. Among them, conductivity in confined systems is a direct probe of the electrostatic environment in the vicinity of the surface. Therefore, we designed a dedicated experiment to measure this conductivity in a cylindrical bubble coupled to interferometry for film thickness characterization. We then show that this conductivity depends on the surfactant nature. These conductivity measurements have been performed in an extremely confined system, the so called Newton black foam films. Unexpectedly in this case, a conductivity close to surface conductivity is recovered.

  9. Analysis Of Wetted-Foam ICF Capsule Perormance

    Science.gov (United States)

    Peterson, R.; Olson, R.; Zylstra, A.; Haines, B.; Yi, A.; Bradley, P.; Yin, L.; Leeper, R.; Kline, J.

    2016-10-01

    The performance of wetted-foam ICF capsules is investigated with the RAGE Eulerian radiation-hydrodynamics computer code. We are developing an experimental platform on NIF that employs a wetted foam liquid DT fuel layer ICF capsules. By varying the capsule temperature, the vapor density in the capsule can be prescribed, and the hot spot convergence ratio (CR) of the capsule implosion can be controlled. This allows us to investigate the fidelity of RAGE in modeling of capsule implosions as the value of CR is varied. In the NIF experiments, CR can be varied from 12 to 25. This presentation will cover simulations with RAGE of three NIF shots performed in 2016; a DD and a DT liquid fuel shot with CR =14 and a DT shot with CR =16. It will also discuss analysis of future experiments. This work was performed under auspices of the U. S. DOE by LANL.

  10. Plastic condoms.

    Science.gov (United States)

    1968-01-01

    Only simple equipment, simple technology and low initial capital investment are needed in their manufacture. The condoms can be made by people who were previously unskilled or only semi-skilled workers. Plastic condoms differ from those made of latex rubber in that the nature of the plastic film allows unlimited shelf-life. Also, the plastic has a higher degree of lubricity than latex rubber; if there is a demand for extra lubrication in a particular market, this can be provided. Because the plastic is inert, these condoms need not be packaged in hermetically sealed containers. All these attributes make it possible to put these condoms on the distributors' shelves in developing countries competitively with rubber condoms. The shape of the plastic condom is based on that of the lamb caecum, which has long been used as luxury-type condom. The plastic condom is made from plastic film (ethylene ethyl acrilate) of 0.001 inch (0.0254 mm.) thickness. In addition, a rubber ring is provided and sealed into the base of the condom for retention during coitus. The advantage of the plastic condom design and the equipment on which it is made is that production can be carried out either in labour-intensive economy or with varying degrees of mechanization and automation. The uniform, finished condom if made using previously untrained workers. Training of workers can be done in a matter of hours on the two machines which are needed to produce and test the condoms. The plastic film is provided on a double wound roll, and condom blanks are prepared by means of a heat-sealing die on the stamping machine. The rubber rings are united to the condom blanks on an assembly machine, which consists of a mandrel and heat-sealing equipment to seal the rubber ring to the base of the condom. Built into the assembly machine is a simple air-testing apparatus that can detect the smallest pinhole flaw in a condom. The manufacturing process is completed by unravelling the condom from the assembly

  11. Plastic Bronchitis.

    Science.gov (United States)

    Rubin, Bruce K

    2016-09-01

    Plastic bronchitis is an uncommon and probably underrecognized disorder, diagnosed by the expectoration or bronchoscopic removal of firm, cohesive, branching casts. It should not be confused with purulent mucous plugging of the airway as seen in patients with cystic fibrosis or bronchiectasis. Few medications have been shown to be effective and some are now recognized as potentially harmful. Current research directions in plastic bronchitis research include understanding the genetics of lymphatic development and maldevelopment, determining how abnormal lymphatic malformations contribute to cast formation, and developing new treatments. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Mixed plastics recycling technology

    CERN Document Server

    Hegberg, Bruce

    1995-01-01

    Presents an overview of mixed plastics recycling technology. In addition, it characterizes mixed plastics wastes and describes collection methods, costs, and markets for reprocessed plastics products.

  13. Novel TiC/Ti Open Cellular Foams Prepared by a Modified Sponge-coating Method Using High Frequency Induction Heating Process

    Institute of Scientific and Technical Information of China (English)

    Yong Gao; Xingxiang Xu; Zhenming Yang; Junqi Zhang; Chunhai Jiang; Jinsong Zhang

    2013-01-01

    A new kind of open cellular foam material with three dimensionally interconnected TiC/Ti struts was prepared by a two-step sponge-coating and high frequency induction heating process.The microstructure,composition and compression strength of the prepared TiC/Ti foam materials were characterized.It was confirmed that the incorporation of Ti into TiC resulted in an inter-bonded Ti-TiC-Ti layered structure in the struts,which enhanced the plasticity of the composite foam materials.

  14. 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...

  15. 塑杯包装封口盖膜揭开力的测试方法%The Test Method for Opening Force on Sealing Cover Film of Plastic Cup Packaging

    Institute of Scientific and Technical Information of China (English)

    张雅君; 王兴; 宋利君

    2014-01-01

    A common open force testing method of plastic cup sealing film was designed based on 10 kinds of plastic cup packagings of jelly and yogurt sample by Electronic universal tensile testing machine,the result betweens 3N to 70N.Finally,the method can be used by researcher in factory and research institute.%通过对10种市售果冻、酸奶塑杯包装类样品设计统一的杯体裁剪方法,对样品进行裁剪处理,利用电子万能拉力试验机进行盖膜揭开力的测试,测试结果集中在3~70N之间,最终建立了果冻、酸奶等盖膜封口形式的塑杯包装开口力的测试方法,为生产厂家、研究机构提供了一种测试盖膜揭开力的方法依据。

  16. Results from the MARBLE Campaign on the National Ignition Facility: Implosion of Foam-Filled Capsules for Studying Thermonuclear Burn in the Presence of Heterogeneous Mix

    Science.gov (United States)

    Murphy, T. J.; Douglas, M. R.; Cardenas, T.; Devolder, B. G.; Fincke, J. R.; Gunderson, M. A.; Haines, B. M.; Hamilton, C. E.; Kim, Y. H.; Lee, M. N.; Oertel, J. A.; Olson, R. E.; Randolph, R. B.; Shah, R. C.; Smidt, J. M.

    2016-10-01

    The MARBLE campaign on NIF investigates the effect of heterogeneous mix on thermonuclear burn for comparison to a probability distribution function (PDF) burn model. MARBLE utilizes plastic capsules filled with deuterated plastic foam and tritium gas. The ratio of DT to DD neutron yield is indicative of the degree to which the foam and the gas atomically mix. Platform development experiments have been performed to understand the behavior of the foam and of the gas separately using two types of capsule. The first uses partially deuterated foam and hydrogen gas fill to understand the burn in the foam. The second uses undeuterated foam and deuterium gas fill to understand the dynamics of the gas. Experiments using deuterated foam and tritium gas are planned. Results of these experiments, and the implications for our understanding of thermonuclear burn in heterogeneously mixed separated reactant experiments will be discussed. This work is supported by US DOE/NNSA, performed at LANL, operated by LANS LLC under contract DE-AC52-06NA25396.

  17. Plastic fish

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness.   Artwork by Wolfgang Trettnak. Packaging materials, consumer goods (shoes, kids’ toys, etc.), leftovers from fishing and aquaculture activities… our oceans and beaches are full of plastic litter. Most of the debris from beaches is plastic bottles. “PET bottles have high durability and stability,” explains Wolfgang Trettnak, a chemist by education and artist from Austria, who gave a lecture on this topic organised by the Staff Association at CERN on 26 May. “PET degrades very slowly and the estimated lifetime of a bottle is 450 years.” In addition to the beach litter accumulated from human use, rivers bring several ki...

  18. Plastic zonnecellen

    NARCIS (Netherlands)

    Roggen, Marjolein

    1998-01-01

    De zonnecel van de toekomst is in de maak. Onderzoekers van uiteenlopend pluimage werken eendrachtig aan een plastic zonnecel. De basis is technisch gelegd met een optimale, door invallend licht veroorzaakte, vorming van ladingdragers binnen een composiet van polymeren en buckyballs. Nu is het zaak

  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. Novel dry polymer foam electrodes for long-term EEG measurement.

    Science.gov (United States)

    Lin, Chin-Teng; Liao, Lun-De; Liu, Yu-Hang; Wang, I-Jan; Lin, Bor-Shyh; Chang, Jyh-Yeong

    2011-05-01

    A novel dry foam-based electrode for long-term EEG measurement was proposed in this study. In general, the conventional wet electrodes are most frequently used for EEG measurement. However, they require skin preparation and conduction gels to reduce the skin-electrode contact impedance. The aforementioned procedures when wet electrodes were used usually make trouble to users easily. In order to overcome the aforesaid issues, a novel dry foam electrode, fabricated by electrically conductive polymer foam covered by a conductive fabric, was proposed. By using conductive fabric, which provides partly polarizable electric characteristic, our dry foam electrode exhibits both polarization and conductivity, and can be used to measure biopotentials without skin preparation and conduction gel. In addition, the foam substrate of our dry electrode allows a high geometric conformity between the electrode and irregular scalp surface to maintain low skin-electrode interface impedance, even under motion. The experimental results presented that the dry foam electrode performs better for long-term EEG measurement, and is practicable for daily life applications.

  1. Vascular plasticity in cerebrovascular disorders

    DEFF Research Database (Denmark)

    Edvinsson, Lars I H; Povlsen, Gro Klitgaard

    2011-01-01

    Cerebral ischemia remains a major cause of morbidity and mortality with little advancement in subacute treatment options. This review aims to cover and discuss novel insight obtained during the last decade into plastic changes in the vasoconstrictor receptor profiles of cerebral arteries and micr...

  2. Field based plastic contamination sensing

    Science.gov (United States)

    The United States has a long-held reputation of being a dependable source of high quality, contaminant-free cotton. Recently, increased incidence of plastic contamination from sources such as shopping bags, vegetable mulch, surface irrigation tubing, and module covers has threatened the reputation o...

  3. Torsion Property of the Structure Bonded Aluminum Foam Due to Impact

    Directory of Open Access Journals (Sweden)

    Hwang G.W.

    2017-06-01

    Full Text Available An aluminum foam added with foaming agent, is classified into an open-cell type for heat transfer and a closed-cell type for shock absorption. This study investigates the characteristic on the torsion of aluminum foam for a closed-cell type under impact. The fracture characteristics are investigated through the composite of five types of aluminum foam (the thicknesses of 25, 35, 45, 55 and 65 mm, when applying the torsional moment of impact energy on the junction of a porous structure attached by an adhesive. When applying the impact energy of 100, 200 and 300J, the aluminum foams with thicknesses of 25 mm and 35 mm broke off under all conditions. For the energy over 200J, aluminums thicker than 55 mm continued to be attached. Furthermore, the aluminum specimens with thicknesses of 55 mm and 65 mm that were attached with more than 30% of bonding interface remained, proving that they could maintain bonding interface against impact energy. By comparing the data based on the analysis and test result, an increase in the thickness of specimen leads to the plastic deformation as the stress at the top and bottom of bonding interface moves to the middle by spreading the stress horizontally. Based on this fracture characteristic, this study can provide the data on the destruction and separation of bonding interface and may contribute to the safety design.

  4. Foam injection molding of polypropylene/stainless steel fiber composites for efficient EMI shielding

    Science.gov (United States)

    Ameli, A.; Nofar, M.; Saniei, M.; Wang, S.; Park, C. B.

    2016-03-01

    Lightweight polypropylene/stainless-steel fiber (PP-SSF) composites with 15-35% density reduction were fabricated using foam injection molding and supercritical carbon dioxide (CO2). The electrical percolation threshold, through-plane electrical conductivity, and electromagnetic interference (EMI) shielding effectiveness (SE) of the PP-SSF composite foams were characterized and compared against the solid samples. The effects of the plasticizing gas and the void fraction on fiber breakage and orientation were also investigated. Microstructure characterization showed that the presence of dissolved CO2 decreased fiber breakage by about 30%, and together with foaming action, contributed to less preferential orientation of fibers. Consequently, the percolation threshold decreased up to four folds from 0.85 to 0.21 vol.% as the void fraction increased from 0 to 35%. The specific EMI SE was also significantly enhanced. A maximum specific EMI SE of 75 dB.g-1cm3 was achieved in PP-1.1 vol.% SSF composite foams, which was highly superior to 38 dB.g-1cm3 of the solid PP-1.0 vol.% SSF composites. The results reveal that light and efficient products with a lower fiber content can be developed by foam for EMI shielding applications.

  5. Lightweight polypropylene/stainless-steel fiber composite foams with low percolation for efficient electromagnetic interference shielding.

    Science.gov (United States)

    Ameli, Aboutaleb; Nofar, Mohammadreza; Wang, Sai; Park, Chul B

    2014-07-23

    Lightweight polypropylene/stainless-steel fiber (PP-SSF) composites with 15-35% density reduction were fabricated using foam injection molding. The electrical percolation threshold, through-plane electrical conductivity, and electromagnetic interference (EMI) shielding effectiveness (SE) of the PP-SSF composite foams were characterized and compared against the solid counterparts. With 3 wt % CO2 dissolved in PP as a temporary plasticizer and lubricant, the fiber breakage was significantly decreased during injection molding, and well-dispersed fibers with unprecedentedly large aspect ratios of over 100 were achieved. The percolation threshold was dramatically decreased from 0.85 to 0.21 vol %, accounting for 75% reduction, which is highly superior, compared to 28% reduction of the previous PP-carbon fiber composite foam.1 Unlike the case of carbon fiber,1 SSFs were much longer than the cell size, and the percolation threshold reduction of PP-SSF composite foams was thus primarily governed by the decreased fiber breakage instead of fiber orientation. The specific EMI SE was also significantly enhanced. A maximum specific EMI SE of 75 dB·g(-1)·cm(3) was achieved in PP-1.1 vol % SSF composite foams, which was much higher than that of the solid counterpart. Also, the relationships between the microstructure and properties were discussed. The mechanism of EMI shielding enhancement was also studied.

  6. 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.

  7. 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.

  8. Sganzerla Cover

    Directory of Open Access Journals (Sweden)

    Victor da Rosa

    2014-06-01

    Full Text Available http://dx.doi.org/10.5007/2175-7917.2014v19n1p158 Neste artigo, realizo uma leitura do cinema de Rogério Sganzerla, desde o clássico O bandido da luz vermelha até os documentários filmados na década de oitenta, a partir de duas noções centrais: cover e over. Para isso, parto de uma controvérsia com o ensaio de Ismail Xavier, Alegorias do subdesenvolvimento, em que o crítico realiza uma leitura do cinema brasileiro da década de sessenta através do conceito de alegoria; depois releio uma série de textos críticos do próprio Sganzerla, publicados em Edifício Sganzerla, procurando repensar as ideias de “herói vazio” ou “cinema impuro” e sugerindo assim uma nova relação do seu cinema com o tempo e a representação; então busco articular tais ideias com certos procedimentos de vanguarda, como a falsificação, a cópia, o clichê e a colagem; e finalmente procuro mostrar que, no cinema de Sganzerla, a partir principalmente de suas reflexões sobre Orson Welles, a voz é usada de maneira a deformar a interpretação naturalista.

  9. Cover Picture.

    Science.gov (United States)

    Breuning; Ruben; Lehn; Renz; Garcia; Ksenofontov; Gütlich; Wegelius; Rissanen

    2000-07-17

    The cover picture shows how both, fine arts and science, avail themselves of a system of intertwined symbolic and iconic languages. They make use of a common set of abstracted signs to report on their results. Thus, already in 1925, Wassily Kandinsky painted a masterpiece (bottom), which now, 75 years later, might be regarded as a blueprint for a scientific project. In his painting, Kandinsky pictured a grid-shaped sign that resembles in effect an actual molecular switch. Apparently following an enigmatic protocol, the groups of Lehn and Gütlich (see p. 2504 ff. for more details) constructed a grid-type inorganic architecture that operates as a three-level magnetic switch (center) triggered by three external perturbations (p, T, hnu). The switching principle is based on the spin-crossover phenomenon of Fe(II) ions and can be monitored by Mössbauer spectroscopy (left) and magnetic measurements (rear). Maybe not by chance, the English translation of the title of the painting "signs" is a homonym of "science", since both presented works are a product of the insatiable curiosity of man and his untiring desire to recognize his existence.

  10. 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

  11. 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.

  12. Plastic Surgery Statistics

    Science.gov (United States)

    ... PSN PSEN GRAFT Contact Us News Plastic Surgery Statistics Plastic surgery procedural statistics from the American Society of Plastic Surgeons. Statistics by Year Print 2016 Plastic Surgery Statistics 2015 ...

  13. 29 CFR 1910.163 - Fixed extinguishing systems, water spray and foam.

    Science.gov (United States)

    2010-07-01

    ....160. This section does not apply to automatic sprinkler systems which are covered under § 1910.159. (b... working and that no emergency egress is permitted through the drainage path. Other Fire Protection Systems ... 29 Labor 5 2010-07-01 2010-07-01 false Fixed extinguishing systems, water spray and foam....

  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. 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.

  17. 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.

  18. 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.)

  19. 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"

  20. 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.

  1. 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...

  2. 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.

  3. 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.

  4. 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...

  5. 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 ...

  6. 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).

  7. 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.

  8. 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.

  9. Plastic bronchitis

    Directory of Open Access Journals (Sweden)

    Anil Kumar Singhi

    2015-01-01

    Full Text Available Plastic bronchitis, a rare but serious clinical condition, commonly seen after Fontan surgeries in children, may be a manifestation of suboptimal adaptation to the cavopulmonary circulation with unfavorable hemodynamics. They are ominous with poor prognosis. Sometimes, infection or airway reactivity may provoke cast bronchitis as a two-step insult on a vulnerable vascular bed. In such instances, aggressive management leads to longer survival. This report of cast bronchitis discusses its current understanding.

  10. 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.

  11. 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.

  12. 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.

  13. The effect of heat and mass transfer on the cellular plastic insulation and the long-term aging

    Energy Technology Data Exchange (ETDEWEB)

    Fan Youchen [VTT Building Technology, Espoo (Finland). Building Physics, Building Services and Fire Technology

    1997-12-31

    To produce environmental-friendly products, foamed plastic industries are facing the challenge to replace the traditional blowing agents chlorofluorocarbons (CFCs) with zero ozone depletion potential (ODP) alternatives. After a series of studies were completed, more understandings and new findings have been achieved with respect to the rigid closed-cell cellular plastic insulations or foamed plastic insulations (FPIs). The mechanism of heat transfer within the FPIs was examined. A new formula for calculating the solid polymer matrix thermal conductivity has been deduced based on the law of energy conservation and Fourier equation of heat conduction. All the parameters involved in this formula can be easily measured. By comparing the simulation results with measurements, the Brokaw equation is recommended for the prediction of the thermal conductivity of a cell-gas mixture. The foamed plastic deformation was also discussed. A new model has been established for predicting the elastic modulus of the foamed plastics. In comparison to the published measurements, it was found that the new model gives fairly good results. A diffusion chamber has been designed and constructed for measuring the gaseous transport properties within the FPIs. To overcome the difficulties of the traditional method, a new measurement procedure and post test data treatment have been suggested. The measurement accuracy is equivalent to the traditional method with an exception of much short time being required. The diffusion coefficients of CO{sub 2}, O{sub 2}, and N{sub 2} within five n-pentane/CO{sub 2} based polyurethane (PUR) foams have been obtained from the diffusion chamber tests. Measurements showed that the relationship between the gaseous diffusion coefficients within FPIs and temperature follows the Arrhenius type. No identical relationship between diffusion coefficients and foam density was reached. To predict the long-term aging property of CFC-free foamed plastic insulations, a two

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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)

  20. 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.

  1. 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.

  2. INFLUENCE OF WATER-TO-CEMENT RATIO ON AIR ENTRAILMENT IN PRODUCTION OF NON-AUTOCLAVED FOAM CONCRETE USING TURBULENCE CAVITATION TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Gorshkov Pavel Vladimirovich

    2012-10-01

    Full Text Available Non-autoclaved foam concrete is an advanced thermal insulation material. Until recently, foam concrete production has been based on separate preparation of foam and solution, followed by their blending in a mixer. The situation changed when high-quality synthetic foaming agents and turbulence cavitation technology appeared on the market. Every model provides a dependence between the foam concrete strength and the water-to-cement ratio. According to the water-cement ratio we can distinguish strong concrete mixtures (with the water-to-cement ratio equal to 0.3…0.4 and ductile ones (with the water-to-cement ratio equal to 0.5…0.7. Strong concrete mixtures are more durable. The lower the water-to-cement ratio, the higher the foam concrete strength. However super-plastic substances cannot be mixed by ordinary turbulent mixers. Foam concrete produced using the turbulence cavitation technology needs air-entraining, its intensity being dependent on several factors. One of the main factors is the amount of free water, if it is insufficient, the mixture will not be porous enough. A researcher needs to identify the optimal water-to-cement ratio based on the water consumption rate. Practical production of prefabricated concrete products and structures has proven that the reduction of the water-to-cement ratio improves the strength of the product. The task is to find the water-to-cement ratio for the foam concrete mixture to be plastic enough for air entraining. An increase in the ratio causes loss in the strength. The ratio shall vary within one hundredth points. Super-plasticizers are an alternative solution.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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)

  6. 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.

  7. The Size Spectrum as Tool for Analyzing Marine Plastic Pollution

    KAUST Repository

    Martí, E.

    2016-12-02

    Marine plastic debris spans over six orders of magnitude in lineal size, from microns to meters. The broad range of plastic sizes mainly arises from the continuous photodegradation and fragmentation affecting the plastic objects. Interestingly, this time-dependent process links, to some degree, the size to the age of the debris. The variety of plastic sizes gives the possibility to marine biota to interact and possible take up microplastics through numerous pathways. Physical processes such as sinking and wind-induced transport or the chemical adsorption of contaminants are also closely related to the size and shape of the plastic items. Likewise, available sampling techniques should be considered as partial views of the marine plastic size range. This being so and given that the size is one of the most easily measurable plastic traits, the size spectrum appears as an ideal frame to arrange, integrate, and analyze plastic data of diverse nature. In this work, we examined tens of thousands of plastic items sampled from across the world with the aim of (1) developing and standardizing the size-spectrum tool to study marine plastics, and (2) assembling a global plastic size spectrum (GPSS) database, relating individual size measurements to abundance, color (129 tons), polymer type, and category (rigid fragments, films, threads, foam, pellets, and microbeads). Using GPSS database, we show for instance the dependence of plastic composition on the item size, with high diversity of categories for items larger than 1 cm and a clear dominance (~90%) of hard fragments below, except for the size interval corresponding to microbeads (around 0.5 mm). GPSS database depicts a comprehensive size-based framework for analyzing the marine plastic pollution, enabling the comparison of size-related studies or the testing of hypothesis.

  8. 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.

  9. Acoustic Test Results of Melamine Foam with Application to Payload Fairing Acoustic Attenuation Systems

    Science.gov (United States)

    Hughes, William O.; McNelis, Anne M.

    2014-01-01

    A spacecraft at launch is subjected to a harsh acoustic and vibration environment resulting from the passage of acoustic energy, created during the liftoff of a launch vehicle, through the vehicle's payload fairing. In order to ensure the mission success of the spacecraft it is often necessary to reduce the resulting internal acoustic sound pressure levels through the usage of acoustic attenuation systems. Melamine foam, lining the interior walls of the payload fairing, is often utilized as the main component of such a system. In order to better understand the acoustic properties of melamine foam, with the goal of developing improved acoustic attenuation systems, NASA has recently performed panel level testing on numerous configurations of melamine foam acoustic treatments at the Riverbank Acoustical Laboratory. Parameters assessed included the foam's thickness and density, as well as the effects of a top outer cover sheet material and mass barriers embedded within the foam. This testing followed the ASTM C423 standard for absorption and the ASTM E90 standard for transmission loss. The acoustic test data obtained and subsequent conclusions are the subjects of this paper.

  10. 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.

  11. 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

  12. 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

  13. 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

  14. Overcoming maladaptive plasticity through plastic compensation

    Directory of Open Access Journals (Sweden)

    Matthew R.J. MORRIS, Sean M. ROGERS

    2013-08-01

    Full Text Available Most species evolve within fluctuating environments, and have developed adaptations to meet the challenges posed by environmental heterogeneity. One such adaptation is phenotypic plasticity, or the ability of a single genotype to produce multiple environmentally-induced phenotypes. Yet, not all plasticity is adaptive. Despite the renewed interest in adaptive phenotypic plasticity and its consequences for evolution, much less is known about maladaptive plasticity. However, maladaptive plasticity is likely an important driver of phenotypic similarity among populations living in different environments. This paper traces four strategies for overcoming maladaptive plasticity that result in phenotypic similarity, two of which involve genetic changes (standing genetic variation, genetic compensation and two of which do not (standing epigenetic variation, plastic compensation. Plastic compensation is defined as adaptive plasticity overcoming maladaptive plasticity. In particular, plastic compensation may increase the likelihood of genetic compensation by facilitating population persistence. We provide key terms to disentangle these aspects of phenotypic plasticity and introduce examples to reinforce the potential importance of plastic compensation for understanding evolutionary change [Current Zoology 59 (4: 526–536, 2013].

  15. Overcoming maladaptive plasticity through plastic compensation

    Institute of Scientific and Technical Information of China (English)

    Matthew R.J.MORRIS; Sean M.ROGERS

    2013-01-01

    Most species evolve within fluctuating environments,and have developed adaptations to meet the challenges posed by environmental heterogeneity.One such adaptation is phenotypic plasticity,or the ability of a single genotype to produce multiple environmentally-induced phenotypes.Yet,not all plasticity is adaptive.Despite the renewed interest in adaptive phenotypic plasticity and its consequences for evolution,much less is known about maladaptive plasticity.However,maladaptive plasticity is likely an important driver of phenotypic similarity among populations living in different environments.This paper traces four strategies for overcoming maladaptive plasticity that result in phenotypic similarity,two of which involve genetic changes (standing genetic variation,genetic compensation) and two of which do not (standing epigenetic variation,plastic compensation).Plastic compensation is defined as adaptive plasticity overcoming maladaptive plasticity.In particular,plastic compensation may increase the likelihood of genetic compensation by facilitating population persistence.We provide key terms to disentangle these aspects of phenotypic plasticity and introduce examples to reinforce the potential importance of plastic compensation for understanding evolutionary change.

  16. 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.

  17. 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.

  18. Vascular plasticity in cerebrovascular disorders

    DEFF Research Database (Denmark)

    Edvinsson, Lars I H; Povlsen, Gro Klitgaard

    2011-01-01

    Cerebral ischemia remains a major cause of morbidity and mortality with little advancement in subacute treatment options. This review aims to cover and discuss novel insight obtained during the last decade into plastic changes in the vasoconstrictor receptor profiles of cerebral arteries and micr......Cerebral ischemia remains a major cause of morbidity and mortality with little advancement in subacute treatment options. This review aims to cover and discuss novel insight obtained during the last decade into plastic changes in the vasoconstrictor receptor profiles of cerebral arteries...... therapeutic target for prevention of vasoconstrictor receptor upregulation after stroke. Together, those findings provide new perspectives on the pathophysiology of ischemic stroke and point toward a novel way of reducing vasoconstriction, neuronal cell death, and thus neurologic deficits after stroke....

  19. 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

  20. 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.

  1. Mechanical Properties of NiTi-Based Foam with High Porosity for Implant Applications

    Science.gov (United States)

    Qiu, Ying; Yu, Hao; Young, Marcus L.

    2015-11-01

    In order to better understand NiTi-based shape memory alloy foams for implant applications, Ni40Ti50Cu10 foams were heat treated and then deformed under incremental and cyclic compression loading. After heat treatment, the microstructure consists of a (Ni,Cu)Ti matrix with small (Ni,Cu)4Ti3 precipitates and a large Ti2(Ni,Cu) secondary phase. The heat-treated Ni40Ti50Cu10 foam exhibits a two-step transformation, involving B19' → B19 and B19 → B2 on heating and B2 → B19 and B19 → B19' on cooling, respectively. One Ni40Ti50Cu10 foam was compression loaded for 10 cycles at each subsequent strain level, i.e., 1, 2, 3, 4, 5, and 6 % strain. In each set of compressive stress-strain loops, the maximum stress level decreases due to plastic damage accumulation and/or retention of transformed martensite. Cross-sectional images from micro-computed tomography were collected during compression loading, which shows very uniform deformation without severe structural damage even up to 5 % strain. Localized deformation is visible at 6 % strain.

  2. 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...

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. 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.

  10. Recycling of Plastic

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Fruergaard, Thilde

    2011-01-01

    Plastic is produced from fossil oil. Plastic is used for many different products. Some plastic products like, for example, wrapping foil, bags and disposable containers for food and beverage have very short lifetimes and thus constitute a major fraction of most waste. Other plastic products like......, good strength and long durability. Recycling of plastic waste from production is well-established, while recycling of postconsumer plastic waste still is in its infancy. This chapter describes briefly how plastic is produced and how waste plastic is recycled in the industry. Quality requirements...

  11. Influence of Cover Type on Silage Quality in Bunker Silos

    Science.gov (United States)

    The quality of silage under reduced oxygen-permeability plastic film systems vs. standard white polyethylene film and tires was evaluated. In six trials (four in whole-plant corn, two in alfalfa), the Silostop two-step covering system (oxygen-barrier film on the side walls and top, woven plastic tar...

  12. 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.

  13. 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.

  14. 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

  15. Medidas radiométricas em casas de vegetação com cobertura plástica na região de Campinas - SP Radiometric measurement of greenhouses with plastic cover at Campinas region- SP

    Directory of Open Access Journals (Sweden)

    Edilson Costa

    2011-06-01

    Full Text Available Com o objetivo de caracterizar as relações e alterações radiométricas em três casas de vegetação, cobertas com filme transparente de polietileno de baixa densidade (PEBD de camada simples com 150µm de espessura, tratado contra raios ultravioleta, sob ambientes distintos, foram realizados os experimentos durante o cultivo hidropônico de alface, cultivar Vera, na região de Campinas - SP, em diferentes períodos do ano, visando ao uso de dados experimentais de postos meteorológicos em substituição à necessidade de adquirir equipamentos de radiação para medições internas. As casas de vegetação eram de estrutura metálica de aço, de forma e volume idênticos. Coletaram-se a radiação solar global interna e externa (RSGI e RSGE, W m-2, a radiação fotossinteticamente ativa (RFA, µmol m-2 s-1 e a radiação ultravioleta, em 254; 312 e 365 nm (RUV, W m-2. Os resultados mostraram que as equações de regressão linear são estimativas aceitáveis na obtenção da radiação fotossinteticamente ativa em função da radiação solar global externa. Em ambientes fechados e climatizados, existe maior correlação entre a radiação fotossinteticamente ativa e a radiação solar global externa. A orientação das casas de vegetação não climatizadas não influencia no espalhamento interno da radiação fotossinteticamente ativa.The objective of this study was to characterize the radiometric relationship and changing in three greenhouses covered with transparent low density polyethylene film (PEBD with a 150µm single layer of low density polyethylene film, treated with compounds that inhibit rapid degradation by ultraviolet radiation, under effects of different environments. The experiments were conducted during hydroponics lettuce production of Vera variety at Campinas region-SP in different periods of the year, aiming the use of experimental data from meteorological stations in substitution of the needs to pursue radiometric

  16. Land Cover - Minnesota Land Cover Classification System

    Data.gov (United States)

    Minnesota Department of Natural Resources — Land cover data set based on the Minnesota Land Cover Classification System (MLCCS) coding scheme. This data was produced using a combination of aerial photograph...

  17. Water-Blown Polyurethane Foams Showing a Reversible Shape-Memory Effect

    Directory of Open Access Journals (Sweden)

    Elena Zharinova

    2016-11-01

    Full Text Available Water-blown polyurethane (PU foams are of enormous technological interest as they are widely applied in various fields, i.e., consumer goods, medicine, automotive or aerospace industries. The discovery of the one-way shape-memory effect in PU foams provided a fresh impetus for extensive investigations on porous polymeric actuators over the past decades. High expansion ratios during the shape-recovery are of special interest when big volume changes are required, for example to fill an aneurysm during micro-invasive surgery or save space during transportation. However, the need to program the foams before each operation cycle could be a drawback impeding the entry of shape-memory polymeric (SMP foams to our daily life. Here, we showed that a reversible shape-memory effect (rSME is achievable for polyurethane water-blown semicrystalline foams. We selected commercially available crystallizable poly(ε-caprolactone-diols of different molecular weight for foams synthesis, followed by investigations of morphology, thermal, thermomechanical and shape-memory properties of obtained compositions. Densities of synthesized foams varied from 110 to 180 kg∙m−3, while peak melting temperatures were composition-dependent and changed from 36 to 47 °C, while the melting temperature interval was around 15 K. All semicrystalline foams exhibited excellent one-way SME with shape-fixity ratios slightly above 100% and shape-recovery ratios from the second cycle of 99%. The composition with broad distribution of molecular weights of poly(ε-caprolactone-diols exhibited an rSME of about 12% upon cyclic heating and cooling from Tlow = 10 °C and Thigh = 47 °C. We anticipate that our experimental study opens a field of systematic investigation of rSMEs in porous polymeric materials on macro and micro scale and extend the application of water-blown polyurethane foams to, e.g., protective covers with zero thermal expansion or even cushions adjustable to a certain body

  18. Comportamento produtivo da videira 'Niagara Rosada' em diferentes sistemas de condução, com e sem cobertura plástica, durante as safras de inverno e de verão Evaluation of vertical and "y" training systems and overhead plastic cover on 'Niagara Rosada' grape yield, during summer and winter growing seasons

    Directory of Open Access Journals (Sweden)

    José Luiz Hernandes

    2013-03-01

    Full Text Available Na região de Jundiaí (SP, os produtores de uva de mesa utilizam principalmente a cultivar Niagara Rosada. Atualmente, para aumentar a renda, o viticultor usa algumas alternativas tecnológicas que têm sido preconizadas, como o cultivo em manjedoura na forma de Y, em substituição ao sistema de condução em espaldeira; a poda extemporânea que permite duas safras por ano (de verão e de inverno e o uso de cobertura plástica para a proteção dos cachos contra intempéries e doenças. Portanto, foi desenvolvido um experimento visando a caracterizar a influência do sistema de condução, do uso de cobertura plástica e da poda extemporânea na produção e no tamanho dos cachos de 'Niagara Rosada'. Os resultados obtidos durante as safras de verão (2008 e 2009 e de inverno (2009 e 2010 permitiram verificar que, no sistema de condução em Y, foram obtidas maiores produções e tamanho de cacho em relação ao espaldeira. O uso de cobertura plástica no sistema em Y propiciou aumento de produção devido ao incremento em número e massa dos cachos. Também foi verificado que tanto a produção quanto a massa do cacho foram superiores na safra de verão em comparação à de inverno.The Niagara Rosada is the most important table grape cultivar for growers from Jundiaí region (São Paulo, Brazil. Currently, aiming to increase the grower benefit some technological alternatives have been recommended such as training system in a Y shape on replacement to unilateral single cordon with three vertical catch wires; application of off-season pruning that allows to obtain two harvests per year (summer and winter and the use of plastic overhead cover to protect the vine's clusters against hailstorm and diseases occurrence. Therefore a field trial was carried out aiming to characterize the influence of the "Y" trellis system and the use of plastic overhead cover on yield and cluster size of 'Niagara Rosada' table grape. The obtained results during the

  19. Investigation of heat transfer in cereal-based foam from a micro-scale perspective using the lattice Boltzmann method

    Science.gov (United States)

    Mack, Simone; Hussein, Mohamed A.; Becker, Thomas

    2011-12-01

    Foam materials are multicomponent and multiphase systems, where under the influence of heat several temperature-dependent processes occur. In cereal-based foams these processes include protein denaturation, starch gelatinization, phase changes such as water evaporation, and structural changes covering bubble expansion and coalescence. This research focuses on modeling heat transfer processes in cereal foams under thermal treatment from a microstructural point of view. The complex thermo-fluidic processes inside the foam are considered for the solid and the gaseous phase, respectively. Additionally, the microstructural foam characteristics are modified to establish their effect on the overall heat transfer rate, and the micro-scale dynamics are introduced by means of lattice Boltzmann methods (LBM). The objective of this study is to deliver sophisticated insight into the impact of structural properties, due to the fact that optimized parameters would help to improve the bakery industry by means of reduction in baking time, energy, and costs. The results show that altering the porosity and/or the interconnectivity of gas pores in bread crumb influences the overall heat transfer. In comparison to foams having a porosity of 55% and discrete pores, the impact of coalescence exhibits a reduction of baking time of about 2 min. Increasing the porosity about 20% results in reducing the baking time about 7 min.

  20. Effect of antioxidants on thermooxidative stability and technological properties of radiation grafted foam polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Burukhina, G.A.; Berlyant, S.M.; Pleshanov, V.P.

    1986-04-01

    Foam polyethylene (FPE) is used in many industrial applications at temperatures of 65-70%. In order to increase this range of practical utilization the effect of oxidation inhibitors was studied along with thermal stabilization of FPE. It was shown that even with small amounts of antioxidants, the foaming coefficient decreased and the optimal radiation absorption dose increased. Therefore, during stabilization of FPE, the introduced antioxidants should not exceed a level of 1%. The use of soot (in excess of 3%) was found to be advantageous in many cases. It yielded material with greater resistance to photodestruction; ionizing radiation affected it to a minimal extent and it did not migrate from the plastic during exposure to high temperatures. Otherwise, amine antioxidants were more effective than the phenolic antioxidants. 6 references, 3 figures.

  1. Three-dimensional foam flow resolved by fast X-ray tomographic microscopy

    CERN Document Server

    Raufaste, Christophe; Mader, Kevin; Santucci, Stéphane; Mokso, Rajmund

    2015-01-01

    Thanks to ultra fast and high resolution X-ray tomography, we managed to capture the evolution of the local structure of the bubble network of a 3D foam flowing around a sphere. As for the 2D foam flow around a circular obstacle, we observed an axisymmetric velocity field with a recirculation zone, and indications of a negative wake downstream the obstacle. The bubble deformations, quantified by a shape tensor, are smaller than in 2D, due to a purely 3D feature: the azimuthal bubble shape variation. Moreover, we were able to detect plastic rearrangements, characterized by the neighbor-swapping of four bubbles. Their spatial structure suggest that rearrangements are triggered when films faces get smaller than a characteristic area.

  2. The influence of geometric imperfections on the stability of three-layer beams with foam core

    Science.gov (United States)

    Wstawska, Iwona

    2017-01-01

    The main objective of this work is the numerical analysis (FE analysis) of stability of three-layer beams with metal foam core (alumina foam core). The beams were subjected to pure bending. The analysis of the local buckling was performed. Furthermore, the influence of geometric parameters of the beam and material properties of the core (linear and non-linear model) on critical loads values and buckling shape were also investigated. The calculations were made on a family of beams with different mechanical properties of the core (elastic and elastic-plastic material). In addition, the influence of geometric imperfections on deflection and normal stress values of the core and the faces has been evaluated.

  3. 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.)

  4. 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".

  5. 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.).

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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....

  12. 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.

  13. 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

  14. 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.

  15. 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...

  16. 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...

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Hydrocellular foam dressing promotes wound healing along with increases in hyaluronan synthase 3 and PPARα gene expression in epidermis.

    Directory of Open Access Journals (Sweden)

    Takumi Yamane

    Full Text Available BACKGROUND: Hydrocellular foam dressing, modern wound dressing, induces moist wound environment and promotes wound healing: however, the regulatory mechanisms responsible for these effects are poorly understood. This study was aimed to reveal the effect of hydrocellular foam dressing on hyaluronan, which has been shown to have positive effects on wound healing, and examined its regulatory mechanisms in rat skin. METHODOLOGY/PRINCIPAL FINDINGS: We created two full-thickness wounds on the dorsolateral skin of rats. Each wound was covered with either a hydrocellular foam dressing or a film dressing and hyaluronan levels in the periwound skin was measured. We also investigated the mechanism by which the hydrocellular foam dressing regulates hyaluronan production by measuring the gene expression of hyaluronan synthase 3 (Has3, peroxisome proliferator-activated receptor α (PPARα, and CD44. Hydrocellular foam dressing promoted wound healing and upregulated hyaluronan synthesis, along with an increase in the mRNA levels of Has3, which plays a primary role in hyaluronan synthesis in epidermis. In addition, hydrocellular foam dressing enhanced the mRNA levels of PPARα, which upregulates Has3 gene expression, and the major hyaluronan receptor CD44. CONCLUSIONS/SIGNIFICANCE: These findings suggests that hydrocellular foam dressing may be beneficial for wound healing along with increases in hyaluronan synthase 3 and PPARα gene expression in epidermis. We believe that the present study would contribute to the elucidation of the mechanisms underlying the effects of hydrocellular foam dressing-induced moist environment on wound healing and practice evidence-based wound care.

  2. Materials Assessment of Insulating Foam in the 9977 Shipping Package for Long-Term Storage - Annual Report

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-01

    The 9977 shipping package is being evaluated for long-term storage applications in the K-Area Complex (KAC) with specific focus on the packaging foam material. A rigid closed cell polyurethane foam, LAST-A-FOAM® FR-3716, produced by General Plastics Manufacturing Company is sprayed and expands to fill the void between the inner container and the outer shell of the package. The foam is sealed in this annular space and is not accessible. During shipping and storage, the foam experiences higher than ambient temperatures from the heat generated by nuclear material within the package creating the potential for degradation of the foam. A series of experiments is underway to determine the extent of foam degradation. Foam samples of three densities have been aging at elevated temperatures 160 °F, 160 °F + 50% relative humidity (RH), 185 °F, 215 °F, and 250 °F since 2014. Samples were periodically removed and tested. After approximately 80 weeks, samples conditioned at 160 °F, 160 °F + 50% RH, and 185 °F have retained initial property values while samples conditioned at 215 °F have reduced intumescence. Samples conditioned at 250 °F have shown the most degradation, loss of volume, mass, absorbed energy under compression, intumescence, and increased flammability. Based on the initial data, temperatures up to 185 °F have not yet shown an adverse effect on the foam properties and it is recommended that exposure of FR-3716 foam to temperatures in excess of 250 °F be avoided or minimized. Testing will continue beyond the 96 week mark. This will provide additional data to help define the long-term behavior for the lower temperature conditions. Additional testing will be pursued in an attempt to identify transition points (threshold times and temperatures) at the higher temperatures of interest, as well as possible benefits of aging within the relatively oxygen-free environment the foam experiences inside the 9977 shipping package.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. Caracterização físico-química do mosto e do vinho Moscato Giallo em videiras cultivadas sob cobertura de plástico Physicochemical characterization of must and wine Moscato Giallo from grapevines grown under plastic overhead cover

    Directory of Open Access Journals (Sweden)

    Geraldo Chavarria

    2008-07-01

    Full Text Available O objetivo deste trabalho foi avaliar a influência da cobertura de plástico sobre as características físico-químicas do mosto e do vinho da cultivar Moscato Giallo. Na safra 2006, um experimento em delineamento completamente casualizado foi realizado em vinhedo com cobertura de plástico impermeável, e sem cobertura como controle. De cada vinhedo, três microvinificações (20 L foram elaboradas. Foram realizadas avaliações físico-químicas quanto ao: mosto - ºBrix, açúcares redutores, densidade, acidez total, ácido tartárico, ácido málico e pH; e vinho - densidade, graduação alcoólica, acidez total, acidez volátil, pH, extrato seco, açúcares redutores, cinzas, I 420, compostos voláteis e minerais. O mosto das videiras cobertas apresentou maior rendimento, porém, menor concentração de açúcares pelo fato de a maturação das uvas ter-se atrasado. Como conseqüência, os vinhos do cultivo protegido tiveram menor graduação alcoólica, embora tenham sido beneficiados pela sanidade das uvas, com a redução de acetato de etila e acidez volátil. O microclima da cobertura também restringiu a concentração de alguns minerais no vinho, principalmente P e K. A cobertura beneficiou a qualidade enológica, porém requer atraso na data de colheita, para as uvas atingirem adequada maturação fisiológica e tecnológica.The objective of this work was to evaluate the plastic overhead cover (POC effect on must and wine composition of the cultivar Moscato Giallo. In 2006 vintage, it was performed a completely randomly designed experiment, in a vineyard covered with an impermeable plastic cloth, and without covering as control. From each vineyard, three microvinification (20 L were elaborated. Physico-chemical analysis were performed for: musts - ºBrix, reducer sugar contents, density, total acidity, tartaric acid, malic acid and pH; and wines - density, alcohol degree, acidity, volatile acidity, pH, dry extract, reducer sugar

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Recycling of Plastic

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Fruergaard, Thilde

    2011-01-01

    Plastic is produced from fossil oil. Plastic is used for many different products. Some plastic products like, for example, wrapping foil, bags and disposable containers for food and beverage have very short lifetimes and thus constitute a major fraction of most waste. Other plastic products like......, for example, gutters, window frames, car parts and transportation boxes have long lifetimes and thus appear as waste only many years after they have been introduced on the market. Plastic is constantly being used for new products because of its attractive material properties: relatively cheap, easy to form......, good strength and long durability. Recycling of plastic waste from production is well-established, while recycling of postconsumer plastic waste still is in its infancy. This chapter describes briefly how plastic is produced and how waste plastic is recycled in the industry. Quality requirements...

  5. Foamed bitumen stabilization of MSWI bottom ash; Skumbitumenstabilisering av bottenaska fraan avfallsfoerbraenning

    Energy Technology Data Exchange (ETDEWEB)

    Bendz, David [Swedish Geotechnical Inst., Linkoeping (Sweden); Jacobsson, Torbjoern [Swedish National Road and Transport Research Inst., Linkoeping (Sweden); Svensson, Mikael; Flyhammar, Peter [Lund Inst. of Technology (Sweden). Dept. of Water Resources Engineering

    2006-04-15

    Foamed bitumen is a mixture of bitumen, water and air. Bitumen that is heated to 175 deg C expands about 10-30 times compared to its original volume when injecting small amounts of water and air under high pressure. By exposing a granulate material to foamed bitumen the particles will be covered with a bitumen film. This will give the particles hydrophobic properties, as well as a smaller specific surface. At the same time the mechanical properties of the material are expected to improve due to the cohesive properties of the bitumen covered particles. The treatment can be made both offsite and in situ. The objective of this project was to investigate the possibility to treat municipal solid waste bottom ash with foamed bitumen to achieve improved leaching and mechanical properties. The following leaching tests have been performed on the original bottom ash and two foamed bitumen treated ashes with 2 and 4.5 % bitumen, respectively: one-stage batch test (EN 12457-4), pH-static test (prEN 14997), column test (prEN 14405) and monolithic leaching test (NEN 7345). In addition, the specific surface and intra-particle porosity were determined by BET N2 adsorption experiments on selected fractions of bottom ash. The results showed that the specific surface decreased with more than 50 % and manifested itself in a lower buffer capacity at both low and high pH. For most elements no significant difference in leaching behavior where found when comparing the results from the leaching tests for the three materials at their own pH. This is thought to be due to that sufficient specific area available for leaching exists to reach equilibrium despite the foam bitumen treatment. The results from the one-stage batch test show a minor reduction in leaching for Cl{sup -}, S, SO{sub 4}{sup -2}, NO{sub 3}{sup -}, Sb, and Ca for the foamed bitumen treated ashes. The results from the column test of the foamed bitumen stabilized ashes showed an increased leaching of some elements, especially

  6. Thermal and mechanical improvement of aluminum open-cells foams through electrodeposition of copper and graphene

    Directory of Open Access Journals (Sweden)

    Simoncini Alessandro

    2016-01-01

    Full Text Available Thanks to its planar structure, graphene is characterized by unique properties, such as excellent chemical inactivity, high electrical and thermal conductivity, high optical transparency, extraordinary flexibility and high mechanical resistance, which make it suitable in a very wide range of applications. This paper details the state of the art in graphene coating applied to aluminum open-cells foams for the improvement of their mechanical and thermal behavior. Metallic foams are highly porous materials with extremely high convective heat transfer coefficients, thanks to their complex structure of three-dimensional open-cells. Graphene nanoplatelets have been used to improve thermal conductivity of aluminum foams, to make them better suitable during heat transfer in transient state. Also, an improvement of mechanical resistance has been observed. Before electrodeposition, all the samples have been subjected to sandblasting process, to eliminate the oxide layer on the surface, enabling a better adhesion of the coating. Different nanoparticles of graphene have been used. The experimental findings revealed a higher thermal conductivity for aluminum open cells foams electroplated with graphene. Considered the relatively low process costs and the improvements obtainable, these materials are very promising in many technological fields. The topics covered include surface modification, electrochemical plating, thermo-graphic analysis.

  7. Deposition of boron doped diamond and carbon nanomaterials on graphite foam electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Marton, Marian, E-mail: marian.marton@stuba.sk; Vojs, Marian; Kotlár, Mário; Michniak, Pavol; Vančo, Ľubomír; Veselý, Marian; Redhammer, Robert

    2014-09-01

    Highlights: • The possibility of boron doped diamond deposition on porous carbon foam by HFCVD method was demonstrated. • Various carbon forms were synthesized including BDD, thin films of graphite nanosheets, carbon nanowalls, graphite nanotips and its composites. • Carbon nanowalls were overgrown by BDD nanocrystals, thus creating a new type of carbon nanomaterial not published yet, a CNW/BDD composite with a unique Raman spectrum. - Abstract: Boron doped diamond (BDD) has remarkable physical and chemical properties, that makes it an attractive material for electrochemical applications. In this study, deposition process of BDD on porous carbon foam electrodes was performed by HFCVD method. After depositions, the substrates were not homogenously covered by the BDD thin film only. Depending on the deposition temperature, foam porosity and distance from heated filaments, different carbon nanomaterials were synthesized. The boron doped diamond, graphite nanosheets, carbon nanowalls and its composites occurred on the foams outer and inner surfaces. Two new observed types of carbon structures, the carbon nanowalls – boron doped diamond composite and graphite nanotips are analyzed and described. Analyses were made by SEM and Raman spectroscopy. The influence of deposition conditions on the growth process is discussed.

  8. What Medicare Covers

    Science.gov (United States)

    ... What Part A covers Medicare Part A hospital insurance covers inpatient hospital care, skilled nursing facility, hospice, lab tests, surgery, ... Medicare Covers Drug Coverage (Part D) Supplements & Other Insurance Claims & ... doctors, providers, hospitals & plans Where can I get covered medical items? ...

  9. 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...

  10. 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.

  11. 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...

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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...