WorldWideScience

Sample records for foams proper time

  1. On the Determination of Proper Time

    OpenAIRE

    Hurl, Bing; Zhang, Zhi-Yong Wang Hai-Dong

    1998-01-01

    Through the analysis of the definition of the duration of proper time of a particle given by the length of its world line, we show that there is no transitivity of the coordinate time function derived from the definition, so there exists an ambiguity in the determination of the duration of the proper time for the particle. Its physical consequence is illustrated with quantum measurement effect.

  2. Boltzmann babies in the proper time measure

    Energy Technology Data Exchange (ETDEWEB)

    Bousso, Raphael; Bousso, Raphael; Freivogel, Ben; Yang, I-Sheng

    2007-12-20

    After commenting briefly on the role of the typicality assumption in science, we advocate a phenomenological approach to the cosmological measure problem. Like any other theory, a measure should be simple, general, well defined, and consistent with observation. This allows us to proceed by elimination. As an example, we consider the proper time cutoff on a geodesic congruence. It predicts that typical observers are quantum fluctuations in the early universe, or Boltzmann babies. We sharpen this well-known youngness problem by taking into account the expansion and open spatial geometry of pocket universes. Moreover, we relate the youngness problem directly to the probability distribution for observables, such as the temperature of the cosmic background radiation. We consider a number of modifications of the proper time measure, but find none that would make it compatible with observation.

  3. The proper time for antioxidant consumption.

    Science.gov (United States)

    Beaulieu, Michaël; Schaefer, H Martin

    2014-04-10

    Consuming food rich in antioxidants may help organisms to increase their antioxidant defences and avoid oxidative damage. Under the hypothesis that organisms actively consume food for its antioxidant properties, they would need to do so in view of other physiological requirements, such as energy requirements. Here, we observed that Gouldian finches (Erythrura gouldiae) consumed most seeds rich in antioxidants in the middle of the day, while their consumption of staple seeds more profitable in energy intake (and poor in antioxidants) was maximal in the morning and the evening. This consumption of seeds rich in antioxidants in the middle of the day may be explicable (1) because birds took advantage of a time window associated with relaxed energy requirements to ingest antioxidant resources, or (2) because birds consumed antioxidant resources as a response to the highest antioxidant requirements in the middle of the day. If the latter hypothesis holds true, having the possibility to ingest antioxidants should be most beneficial in terms of oxidative balance in the middle of the day. Even though feeding on seeds rich in antioxidants improved Gouldian finches' overall antioxidant capacity, we did not detect any diurnal effect of antioxidant intake on plasma oxidative markers (as measured by the d-ROM and the OXY-adsorbent tests). This indicates that the diurnal pattern of antioxidant intake that we observed was most likely constrained by the high consumption of staple food to replenish or build up body reserves in the morning and in the evening, and not primarily determined by elevated antioxidant requirements in the middle of the day. Consequently, animals appear to have the possibility to increase antioxidant defences by selecting food rich in antioxidants, only when energetic constraints are relaxed. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Determination of proper peaking time for Ultra-LEGe detector

    Energy Technology Data Exchange (ETDEWEB)

    Karabidak, S.M., E-mail: salihm@ktu.edu.t [Department of Physics, Karadeniz Technical University, 61080 Trabzon (Turkey); Department of Engineering Physics, Guemueshane University, 29100 Guemueshane (Turkey); Kaya, S. [Department of Engineering Physics, Guemueshane University, 29100 Guemueshane (Turkey); Cevik, U. [Department of Physics, Karadeniz Technical University, 61080 Trabzon (Turkey); Celik, A. [Department of Physics, Giresun University, 28049 Giresun (Turkey)

    2011-04-15

    Reducing count losses and pile-up pulse effects in quantitative and qualitative analysis is necessary for accuracy of analysis. Therefore, the proper peaking time for particular detector systems is important. The characteristic X-rays emitted from pure some elements were detected by using an Ultra-LEGe detector connecting a Tennelec TC 244 spectroscopy amplifier at different peaking time modes. Overall pulse widths were determined by an HM 203-7 oscilloscope connecting amplifier. The proper peaking time for Ultra-LEGe is determined as 3.84 {mu}s.

  5. A properly adjusted forage harvester can save time and money

    Science.gov (United States)

    A properly adjusted forage harvester can save fuel and increase the realizable milk per ton of your silage. This article details the adjustments necessary to minimize energy while maximizing productivity and forage quality....

  6. 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.

  7. A Note on the Problem of Proper Time in Weyl Space-Time

    Science.gov (United States)

    Avalos, R.; Dahia, F.; Romero, C.

    2018-01-01

    We discuss the question of whether or not a general Weyl structure is a suitable mathematical model of space-time. This is an issue that has been in debate since Weyl formulated his unified field theory for the first time. We do not present the discussion from the point of view of a particular unification theory, but instead from a more general standpoint, in which the viability of such a structure as a model of space-time is investigated. Our starting point is the well known axiomatic approach to space-time given by Elhers, Pirani and Schild (EPS). In this framework, we carry out an exhaustive analysis of what is required for a consistent definition for proper time and show that such a definition leads to the prediction of the so-called "second clock effect". We take the view that if, based on experience, we were to reject space-time models predicting this effect, this could be incorporated as the last axiom in the EPS approach. Finally, we provide a proof that, in this case, we are led to a Weyl integrable space-time as the most general structure that would be suitable to model space-time.

  8. A Note on the Problem of Proper Time in Weyl Space-Time

    Science.gov (United States)

    Avalos, R.; Dahia, F.; Romero, C.

    2018-02-01

    We discuss the question of whether or not a general Weyl structure is a suitable mathematical model of space-time. This is an issue that has been in debate since Weyl formulated his unified field theory for the first time. We do not present the discussion from the point of view of a particular unification theory, but instead from a more general standpoint, in which the viability of such a structure as a model of space-time is investigated. Our starting point is the well known axiomatic approach to space-time given by Elhers, Pirani and Schild (EPS). In this framework, we carry out an exhaustive analysis of what is required for a consistent definition for proper time and show that such a definition leads to the prediction of the so-called "second clock effect". We take the view that if, based on experience, we were to reject space-time models predicting this effect, this could be incorporated as the last axiom in the EPS approach. Finally, we provide a proof that, in this case, we are led to a Weyl integrable space-time as the most general structure that would be suitable to model space-time.

  9. How Students Learn from Multiple Contexts and Definitions: Proper Time as a Coordination Class

    Science.gov (United States)

    Levrini, Olivia; diSessa, Andrea A.

    2008-01-01

    This article provides an empirical analysis of a single classroom episode in which students reveal difficulties with the concept of proper time in special relativity but slowly make progress in improving their understanding. The theoretical framework used is "coordination class theory," which is an evolving model of concepts and conceptual change.…

  10. A proper-time cure for the conformal sickness in quantum gravity

    OpenAIRE

    Dasgupta, A.; Loll, R.

    2001-01-01

    Starting from the space of Lorentzian metrics, we examine the full gravitational path integral in 3 and 4 space-time dimensions. Inspired by recent results obtained in a regularized, dynamically triangulated formulation of Lorentzian gravity, we gauge-fix to proper-time coordinates and perform a non-perturbative ''''Wick rotation'' on the physical configuration space. Under certain assumptions about the behaviour of the partition function under renormalization, we find that the divergence due...

  11. On black holes, space-time foam and the nature of time in string theory

    International Nuclear Information System (INIS)

    Mavromatos, N.E.; Grenoble-1 Univ., 74 - Annecy

    1993-04-01

    It is shown that the light particles in string theory obey an effective quantum mechanics modified by the inclusion of a quantum-gravitational friction term, induced by unavoidable couplings to unobserved massive string states in the space-time foam. This term is related to the W-symmetries that couple light particles to massive solitonic string states in black hole backgrounds, and has a formal similarity to simple models of environmental quantum friction. All properties follow from a definition of target-time as a Renormalization Group scale parameter and the associated (generic) properties of the renormalization group flow. Some experimental consequences, concerning CPT violation detectable in systems that are generally considered as sensitive probes of quantum mechanics (e.g. neutral kaons), are briefly discussed. (author). 52 refs., 1 fig

  12. The foam drainage equation with time- and space-fractional derivatives solved by the Adomian method

    Directory of Open Access Journals (Sweden)

    Zoubir Dahmani

    2008-10-01

    Full Text Available In this paper, by introducing the fractional derivative in the sense of Caputo, we apply the Adomian decomposition method for the foam drainage equation with time- and space-fractional derivative. As a result, numerical solutions are obtained in a form of rapidly convergent series with easily computable components.

  13. Combined time-varying forecast based on the proper scoring approach for wind power generation

    DEFF Research Database (Denmark)

    Chen, Xingying; Jiang, Yu; Yu, Kun

    2017-01-01

    Compared with traditional point forecasts, combined forecast have been proposed as an effective method to provide more accurate forecasts than individual model. However, the literature and research focus on wind-power combined forecasts are relatively limited. Here, based on forecasting error...... distribution, a proper scoring approach is applied to combine plausible models to form an overall time-varying model for the next day forecasts, rather than weights-based combination. To validate the effectiveness of the proposed method, real data of 3 years were used for testing. Simulation results...... demonstrate that the proposed method improves the accuracy of overall forecasts, even compared with a numerical weather prediction....

  14. Foam Glass for Construction Materials

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund

    2016-01-01

    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...... the foaming process for foam glass with closed pores. In addition, it is shown that melt foaming should preferably be performed in a viscosity limited regime. Finally, it is suggested that the foaming agent contributes significantly to the solid conductivity of foam glass....

  15. Stringy Space-Time Foam and High-Energy Cosmic Photons

    CERN Document Server

    Mavromatos, Nick E

    2011-01-01

    In this review, I discuss briefly stringent tests of Lorentz-violating quantum space-time foam models inspired from String/Brane theories, provided by studies of high energy Photons from intense celestial sources, such as Active Galactic Nuclei or Gamma Ray Bursts. The theoretical models predict modifications to the radiation dispersion relations, which are quadratically suppressed by the string mass scale, and time delays in the arrival times of photons (assumed to be emitted more or less simultaneously from the source), which are proportional to the photon energy, so that the more energetic photons arrive later. Although the astrophysics at the source of these energetic photons is still not understood, and such non simultaneous arrivals, that have been observed recently, might well be due to non simultaneous emission as a result of conventional physics effects, nevertheless, rather surprisingly, the observed time delays can also fit excellently the stringy space-time foam scenarios, provided the space-time ...

  16. Thermal aging of traditional and additively manufactured foams: analysis by time-temperature-superposition, constitutive, and finite-element models

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Weisgraber, T. H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Small, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lewicki, J. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Duoss, E. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Spadaccini, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Pearson, M. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chinn, S. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wilson, T. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Maxwell, R. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-12-08

    Cellular solids or foams are a very important class of materials with diverse applications ranging from thermal insulation and shock absorbing support cushions, to light-weight structural and floatation components, and constitute crucial components in a large number of industries including automotive, aerospace, electronics, marine, biomedical, packaging, and defense. In many of these applications the foam material is subjected to long periods of continuous stress, which can, over time, lead to a permanent change in structure and a degradation in performance. In this report we summarize our modeling efforts to date on polysiloxane foam materials that form an important component in our systems. Aging of the materials was characterized by two measured quantities, i.e., compression set and load retention. Results of accelerated aging experiments were analyzed by an automated time-temperaturesuperposition (TTS) approach, which creates a master curve that can be used for long-term predictions (over decades) under ambient conditions. When comparing such master curves for traditional (stochastic) foams with those for recently 3D-printed (i.e., additively manufactured, or AM) foams, it became clear that AM foams have superior aging behavior. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. This indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material.

  17. Maxwell–Lorentz Electrodynamics Revisited via the Lagrangian Formalism and Feynman Proper Time Paradigm

    Directory of Open Access Journals (Sweden)

    Nikolai N. Bogolubov

    2015-04-01

    Full Text Available We review new electrodynamics models of interacting charged point particles and related fundamental physical aspects, motivated by the classical A.M. Ampère magnetic and H. Lorentz force laws electromagnetic field expressions. Based on the Feynman proper time paradigm and a recently devised vacuum field theory approach to the Lagrangian and Hamiltonian, the formulations of alternative classical electrodynamics models are analyzed in detail and their Dirac type quantization is suggested. Problems closely related to the radiation reaction force and electron mass inertia are analyzed. The validity of the Abraham-Lorentz electromagnetic electron mass origin hypothesis is argued. The related electromagnetic Dirac–Fock–Podolsky problem and symplectic properties of the Maxwell and Yang–Mills type dynamical systems are analyzed. The crucial importance of the remaining reference systems, with respect to which the dynamics of charged point particles is framed, is explained and emphasized.

  18. Coalescence measurements for evolving foams monitored by real-time projection imaging

    International Nuclear Information System (INIS)

    Myagotin, A; Helfen, L; Baumbach, T

    2009-01-01

    Real-time radiographic projection imaging together with novel spatio-temporal image analysis is presented to be a powerful technique for the quantitative analysis of coalescence processes accompanying the generation and temporal evolution of foams and emulsions. Coalescence events can be identified as discontinuities in a spatio-temporal image representing a sequence of projection images. Detection, identification of intensity and localization of the discontinuities exploit a violation criterion of the Fourier shift theorem and are based on recursive spatio-temporal image partitioning. The proposed method is suited for automated measurements of discontinuity rates (i.e., discontinuity intensity per unit time), so that large series of radiographs can be analyzed without user intervention. The application potential is demonstrated by the quantification of coalescence during the formation and decay of metal foams monitored by real-time x-ray radiography

  19. Investigation of the Minimum Deployment Time of a Foam/Fabric Composite Material.

    Science.gov (United States)

    1980-09-01

    t 1 .yi lded foam ( at9 room temperdatur0e) rha foam mixture and had to be enlarged to 0.375 in. (9.5 cent or greater closed-cell content. Foam...Weapons Laboratory, September 1968). Marsden, J. N., Quick-Setting Foam Research Support Salyer, 1. 0., J. L. Schwendeman, A. Wojtowicz, R. T. and Spray

  20. 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.

  1. On the classical Maxwell-Lorentz electrodynamics, the electron inertia problem, and the Feynman proper time paradigm

    International Nuclear Information System (INIS)

    Prykarpatsky, A.K.; Bogolubov, J.R.

    2016-01-01

    The classical Maxwell electromagnetic field and the Lorentz-type force equations are rederived in the framework of the Feynman proper time paradigm and the related vacuum field theory approach. The classical Ampere law origin is rederived, and its relationship with the Feynman proper time paradigm is discussed. The electron inertia problem is analyzed in detail within the Lagrangian and Hamiltonian formalisms and the related pressure-energy compensation principle of stochastic electrodynamics. The modified Abraham-Lorentz damping radiation force is derived and the electromagnetic electron mass origin is argued

  2. Proper microtubule structure is vital for timely progression through meiosis in fission yeast.

    Directory of Open Access Journals (Sweden)

    Akira Yamashita

    Full Text Available Cells of the fission yeast Schizosaccharomyces pombe normally reproduce by mitotic division in the haploid state. When subjected to nutrient starvation, two haploid cells fuse and undergo karyogamy, forming a diploid cell that initiates meiosis to form four haploid spores. Here, we show that deletion of the mal3 gene, which encodes a homolog of microtubule regulator EB1, produces aberrant asci carrying more than four spores. The mal3 deletion mutant cells have a disordered cytoplasmic microtubule structure during karyogamy and initiate meiosis before completion of karyogamy, resulting in twin haploid meiosis in the zygote. Treatment with anti-microtubule drugs mimics this phenotype. Mutants defective in karyogamy or mutants prone to initiate haploid meiosis exaggerate the phenotype of the mal3 deletion mutant. Our results indicate that proper microtubule structure is required for ordered progression through the meiotic cycle. Furthermore, the results of our study suggest that fission yeast do not monitor ploidy during meiosis.

  3. Stringy space-time foam, Finsler-like metrics and dark matter relics

    International Nuclear Information System (INIS)

    Mavromatos, Nick E.; Sarkar, Sarben; Vergou, Ariadne

    2011-01-01

    We discuss modifications of the thermal dark matter (DM) relic abundances in stringy cosmologies with D-particle space-time foamy backgrounds. As a result of back-reaction of massive DM on the background space-time, owing to its interaction with D-particle defects in the foam, quantum fluctuations are induced in the space-time metric. We demonstrate that these lead to the presence of extra source terms in the Boltzmann equation used to determine the thermal dark matter relic abundances. The source terms are determined by the specific form of the induced metric deformations; the latter depend on the momentum transfer of the DM particle during its interactions with the D-particle defects and so are akin to Finsler metrics. In the case of low string scales, arising from large extra dimensions, our results may have phenomenological implications for the search of viable supersymmetric models.

  4. 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.

  5. Space-time foam effects on particle interactions and the Greisen-Zatsepin-Kuzmin cutoff

    International Nuclear Information System (INIS)

    Ellis, John; Mavromatos, N. E.; Nanopoulos, D. V.

    2001-01-01

    Modeling space-time foam using a noncritical Liouville-string model for the quantum fluctuations of D-branes with recoil, we discuss the issues of momentum and energy conservation in particle propagation and interactions. We argue that momentum should be conserved exactly during propagation and on the average during interactions, but that energy is conserved only on the average during propagation and is in general not conserved during particle interactions, because of changes in the background metric. We discuss the possible modification of the GZK cutoff on high-energy cosmic rays, in the light of this energy non-conservation as well as the possible modification of the usual relativistic momentum-energy relation

  6. Foam Dispenser

    Science.gov (United States)

    1985-01-01

    William G. Simpson, a NASA/Marshall employee, invented and patented a foam mixing dispensing device. He is supplying his Simpson mixer to a number of foam applications where it is used to apply foam for insulation purposes.

  7. Towards a phase diagram for spin foams

    Science.gov (United States)

    Delcamp, Clement; Dittrich, Bianca

    2017-11-01

    One of the most pressing issues for loop quantum gravity and spin foams is the construction of the continuum limit. In this paper, we propose a systematic coarse-graining scheme for three-dimensional lattice gauge models including spin foams. This scheme is based on the concept of decorated tensor networks, which have been introduced recently. Here we develop an algorithm applicable to gauge theories with non-Abelian groups, which for the first time allows for the application of tensor network coarse-graining techniques to proper spin foams. The procedure deals efficiently with the large redundancy of degrees of freedom resulting from gauge invariance. The algorithm is applied to 3D spin foams defined on a cubical lattice which, in contrast to a proper triangulation, allows for non-trivial simplicity constraints. This mimics the construction of spin foams for 4D gravity. For lattice gauge models based on a finite group we use the algorithm to obtain phase diagrams, encoding the continuum limit of a wide range of these models. We find phase transitions for various families of models carrying non-trivial simplicity constraints.

  8. Derivation of a Vacuum Refractive Index in a Stringy Space-Time Foam Model

    CERN Document Server

    Ellis, Jonathan Richard; Nanopoulos, D V

    2008-01-01

    It has been suggested that energetic photons propagating in vacuo should experience a non-trivial refractive index due to the foamy structure of space-time induced by quantum-gravitational fluctuations. The sensitivity of recent astrophysical observations, particularly of AGN Mk501 by the MAGIC Collaboration, approaches the Planck scale for a refractive index depending linearly on the photon energy. We present here a new derivation of this quantum-gravitational vacuum refraction index, based on a stringy analogue of the interaction of a photon with internal degrees of freedom in a conventional medium. We model the space-time foam as a gas of D-particles in the bulk space-time of a higher-dimensional cosmology where the observable Universe is a D3-brane. The interaction of an open string representing a photon with a D-particle stretches and excites the string, which subsequently decays and re-emits the photon with a time delay that increases linearly with the photon energy and is related to stringy uncertainty...

  9. The Removal of Aquacultural Wastes by Foams Separator from Sea Water II. The Effect of Hydraulic Residence Time

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Kuen Hack; Kim, Byong Jin; Kim, Yong Ha; Yi, Gyeongbeom; Lim, Jung Heok [Department of Chemical Engineering, Pukyong National University, Pusan (Korea); Kim, Sung Koo [Department of Biotechnology and Bioengineering, Pukyong National University, Pusan (Korea)

    2001-04-01

    Experimental investigations on the effect of the hydraulic residence time(HRT) for the removal of aquacultural waste, such as protein, total suspended solids(TSS), chemical oxygen demand(COD), turbidity and total ammonia nitrogen(TAN) from sea water were carried out by using foam separator. The foam separator as an aerator was also evaluated for increasing dissolved oxygen concentration. The increase in hydraulic residence time increased the removal efficiencies of aquacultural waste. Optimum hydraulic residence time was 0.48 min and the highest protein removal rate was 10.25 g/m{sup 3} min. The changes of removal rates and efficiencies of TSS, COD and turbidity were similar to proteins. The hydraulic residence time for highest overall oxygen mass transfer coefficient was the optimum condition for the highest protein removal rate. 23 refs., 15 figs., 1 tab.

  10. Study of Proper Time Range for Current Flow to Resistance Spot Welding Inspected by Mechanical Property and Metallurgy Testing

    International Nuclear Information System (INIS)

    Pearsura, Prachya

    2007-08-01

    Full text: This research used the mechanical property and metallurgy testing to identify the proper time range for current flow. The specimen tested was 1 mm thick mild steel. The welded specimens were tested by Tensile Shear testing following JIS Z 3136: 1999 and Macro Structure testing follow by JIS Z 3139: 1978. Subsequently, the results from analyzing were compared with standard JIS Z 3140. The results show that the suitable current flow is 8 to 10 cycles. This technique can be applied to monitor the process and the quality of resistance spot welding

  11. High performance polymeric foams

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  12. Covariant open bosonic string field theory on multiple D-branes in the proper-time gauge

    Science.gov (United States)

    Lee, Taejin

    2017-12-01

    We construct a covariant open bosonic string field theory on multiple D-branes, which reduces to a non-Abelian group Yang-Mills gauge theory in the zero-slope limit. Making use of the first quantized open bosonic string in the proper time gauge, we convert the string amplitudes given by the Polyakov path integrals on string world sheets into those of the second quantized theory. The world sheet diagrams generated by the constructed open string field theory are planar in contrast to those of the Witten's cubic string field theory. However, the constructed string field theory is yet equivalent to the Witten's cubic string field theory. Having obtained planar diagrams, we may adopt the light-cone string field theory technique to calculate the multi-string scattering amplitudes with an arbitrary number of external strings. We examine in detail the three-string vertex diagram and the effective four-string vertex diagrams generated perturbatively by the three-string vertex at tree level. In the zero-slope limit, the string scattering amplitudes are identified precisely as those of non-Abelian Yang-Mills gauge theory if the external states are chosen to be massless vector particles.

  13. Dynamics of poroelastic foams

    Science.gov (United States)

    Forterre, Yoel; Sobac, Benjamin

    2010-11-01

    Soft poroelastic structures are widespread in biological tissues such as cartilaginous joints in bones, blood-filled placentae or plant organs. Here we investigate the dynamics of open elastic foams immersed in viscous fluids, as model soft poroelastic materials. The experiment consists in slowly compacting blocs of polyurethane solid foam embedded in silicon oil-tanks and studying their relaxation to equilibrium when the confining stress is suddenly released. Measurements of the local fluid pressure and foam velocity field are compared with a simple two-phase flow approach. For small initial compactions, the results show quantitative agreement with the classical diffusion theory of soil consolidation (Terzaghi, Biot). On the other hand, for large initial compactions, the dynamics exhibits long relaxation times and decompaction fronts, which are mainly controlled by the highly non-linear mechanical response of the foam. The analogy between this process and the evaporation of a polymer melt close to the glass transition will be briefly discussed.

  14. 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.

  15. 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.

  16. Polyimide Foams Offer Superior Insulation

    Science.gov (United States)

    2012-01-01

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

  17. Foam-Driven Fractures of an Elastic Matrix

    Science.gov (United States)

    Lai, Ching-Yao; Smiddy, Sam; Stone, Howard

    2015-11-01

    We report an experimental study of foam-driven fractures in an elastic matrix. When a pressurized foam is constantly injected into a gelatin matrix with a constant flow rate, the foam generates a disc-like fracture which is commonly observed in liquid-driven fractures. Compare to liquid-driven fractures, foam-driven fractures grow faster with time. We investigate how the rheological behaviour of foams affects the fracture characteristics by varying the air volume fraction of the foam, the types and concentration of surfactants in the foam. Foam-fracturing reduces the environmental costs of hydraulic fracturing, which inspires this laboratory study.

  18. 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...

  19. Efficient preloading of the ventricles by a properly timed atrial contraction underlies stroke work improvement in the acute response to cardiac resynchronization therapy

    Science.gov (United States)

    Hu, Yuxuan; Gurev, Viatcheslav; Constantino, Jason; Trayanova, Natalia

    2013-01-01

    Background The acute response to cardiac resynchronization therapy (CRT) has been shown to be due to three mechanisms: resynchronization of ventricular contraction, efficient preloading of the ventricles by a properly timed atrial contraction, and mitral regurgitation reduction. However, the contribution of each of the three mechanisms to the acute response of CRT, specifically stroke work improvement, has not been quantified. Objective The goal of this study was to use an MRI-based anatomically accurate 3D model of failing canine ventricular electromechanics to quantify the contribution of each of the three mechanisms to stroke work improvement and identify the predominant mechanisms. Methods An MRI-based electromechanical model of the failing canine ventricles assembled previously by our group was further developed and modified. Three different protocols were used to dissect the contribution of each of the three mechanisms to stroke work improvement. Results Resynchronization of ventricular contraction did not lead to significant stroke work improvement. Efficient preloading of the ventricles by a properly timed atrial contraction was the predominant mechanism underlying stroke work improvement. Stroke work improvement peaked at an intermediate AV delay, as it allowed ventricular filling by atrial contraction to occur at a low diastolic LV pressure but also provided adequate time for ventricular filling before ventricular contraction. Diminution of mitral regurgitation by CRT led to stroke work worsening instead of improvement. Conclusion Efficient preloading of the ventricles by a properly timed atrial contraction is responsible for significant stroke work improvement in the acute CRT response. PMID:23928177

  20. Temper Foam

    Science.gov (United States)

    1981-01-01

    Fabricated by Expanded Rubber & Plastics Corporation, Temper Foam provides better impact protection for airplane passengers and enhances passenger comfort on long flights because it distributes body weight and pressure evenly over the entire contact area. Called a "memory foam" it matches the contour of the body pressing against it and returns to its original shape once the pressure is removed. As a shock absorber, a three-inch foam pad has the ability to absorb the impact of a 10-foot fall by an adult. Applications include seat cushioning for transportation vehicles, padding for furniture and a variety of athletic equipment medical applications including wheelchair padding, artificial limb socket lining, finger splint and hand padding for burn patients, special mattresses for the bedridden and dental stools. Production and sales rights are owned by Temper Foam, Inc. Material is manufactured under license by the Dewey and Almy Division of Grace Chemical Corporation. Distributors of the product are Kees Goebel Medical Specialties, Inc. and Alimed, Inc. They sell Temper Foam in bulk to the fabricators who trim it to shapes required by their customers.

  1. Image Fusion of Preprocedural CTA with Real-time Fluoroscopy to Guide Proper Hepatic Artery Catheterization During Transarterial Chemoembolization of Hepatocellular Carcinoma: A Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Bargellini, Irene, E-mail: irenebargellini@hotmail.com; Turini, Francesca; Bozzi, Elena; Lauretti, Dario; Cicorelli, Antonio; Lunardi, Alessandro; Cioni, Roberto; Bartolozzi, Carlo [University of Pisa, Department of Diagnostic and Interventional Radiology (Italy)

    2013-04-15

    To assess feasibility of proper hepatic artery catheterization using a 3D model obtained from preprocedural computed tomographic angiography (CTA), fused with real-time fluoroscopy, during transarterial chemoembolization of hepatocellular carcinoma. Twenty consecutive cirrhotic patients with hepatocellular carcinoma undergoing transarterial chemoembolization were prospectively enrolled onto the study. The early arterial phase axial images of the preprocedural CTA were postprocessed on an independent workstation connected to the angiographic system (Innova 4100; GE Healthcare, Milwaukee, WI), obtaining a 3D volume rendering image (VR) that included abdominal aorta, splanchnic arteries, and first and second lumbar vertebrae. The VR image was manually registered to the real-time X-ray fluoroscopy, with the lumbar spine used as the reference. The VR image was then used as guidance to selectively catheterize the proper hepatic artery. The procedure was considered successful when performed with no need for intraarterial contrast injections or angiographic acquisitions. The procedure was successful in 19 (95 %) of 20 patients. In one patient, celiac trunk angiography was required for the presence of a significant ostial stenosis that was underestimated at computed tomography. Time for image reconstruction and registration was <10 min in all cases. The use of preprocedural CTA model with fluoroscopy enables confident and direct catheterization of the proper hepatic artery with no need for preliminary celiac trunk angiography, thus reducing radiation exposure and contrast media administration.

  2. Determination of Proper Application Timing and Frequency for Management of Tomato Leaf Mold Disease by Commercially Available Microbial Preparations

    Directory of Open Access Journals (Sweden)

    Beom Ryong Kang

    2011-08-01

    Full Text Available In order to develop a environmentally friendly control protocol for managing tomato leaf mold disease in the field, we employed bacteria- and fungi-based commercially available microbial preparations. The field experiment was conducted from April to July in 2010. Average incidence rates tomato leaf mold caused by Fulvia fulva were 13.1% at the two plastic houses located in Jangsung, Jeonnam area. Initially 11 microbial preparations were tested for antifungal activity against F. fulva in vitro. Among them, 7 selected preparations showed to be inhibited the mycelial growth of the fungal pathogen over 50%. Four microbes suppressed disease incidence as much 50% under greenhouse condition. Eventually in the field two microbial products including Bacillus subtilis GB-0365 and B. subtilis KB-401 respectively were showed control value up to 71.8% for four times sprays from 20 days to 70 days after transplanting. Furthermore, the control value of three times spray program demonstrated 79.3%. Efficacy of the three and four spray programs was more effective than that of non-spray control treatment. Our results indicated that adjustment of application method of commercially available microbial preparation could be used to control a target plant disease as an effective and efficient crop protection system for organic farming.

  3. Foams in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Marsden, S.S.

    1986-07-01

    In 1978 a literature search on selective blocking of fluid flow in porous media was done by Professor S.S. Marsden and two of his graduate students, Tom Elson and Kern Huppy. This was presented as SUPRI Report No. TR-3 entitled ''Literature Preview of the Selected Blockage of Fluids in Thermal Recovery Projects.'' Since then a lot of research on foam in porous media has been done on the SUPRI project and a great deal of new information has appeared in the literature. Therefore we believed that a new, up-to-date search should be done on foam alone, one which would be helpful to our students and perhaps of interest to others. This is a chronological survey showing the development of foam flow, blockage and use in porous media, starting with laboratory studies and eventually getting into field tests and demonstrations. It is arbitrarily divided into five-year time periods. 81 refs.

  4. The Controversy of the Most Proper Time for Pregnancy After Bariatric Surgery: a Review of Ten Cases.

    Science.gov (United States)

    Chaichian, Shahla; Moazzami, Bahram; Jesmi, Fatemeh; Pazouki, Abdolreza; Pishgahroudsari, Mohadeseh; Mokhber, Somayeh; Riazi, Sajedeh

    2016-06-01

    Many infertile obese women conceive after bariatric surgery after many years, while guidelines prohibit them from pregnancy for at least 12-18 months after surgery, due to complications. We hereby present 11 cases in our research center, pregnant in less than 12 months after surgery from 2011 to 2015, to evaluate their pregnancy outcome and complications. The mean conception time was 3.6 months after surgery and mean birth weight was 2695 g. Regarding neonatal/fetal complications, there was one case of intrauterine growth retardation and one NICU hospitalization. Among pregnancy complications, eight patients had hyperemesis gravidarum and one had pre-eclampsia. The results of the present study suggest revising setting a contraindication for conception for patients undergoing bariatric surgery.

  5. Arabidopsis thaliana VOZ (Vascular plant One-Zinc finger) transcription factors are required for proper regulation of flowering time.

    Science.gov (United States)

    Celesnik, Helena; Ali, Gul S; Robison, Faith M; Reddy, Anireddy S N

    2013-04-15

    Transition to flowering in plants is tightly controlled by environmental cues, which regulate the photoperiod and vernalization pathways, and endogenous signals, which mediate the autonomous and gibberellin pathways. In this work, we investigated the role of two Zn(2+)-finger transcription factors, the paralogues AtVOZ1 and AtVOZ2, in Arabidopsis thaliana flowering. Single atvoz1-1 and atvoz2-1 mutants showed no significant phenotypes as compared to wild type. However, atvoz1-1 atvoz2-1 double mutant plants exhibited several phenotypes characteristic of flowering-time mutants. The double mutant displayed a severe delay in flowering, together with additional pleiotropic phenotypes. Late flowering correlated with elevated expression of FLOWERING LOCUS C (FLC), which encodes a potent floral repressor, and decreased expression of its target, the floral promoter FD. Vernalization rescued delayed flowering of atvoz1-1 atvoz2-1 and reversed elevated FLC levels. Accumulation of FLC transcripts in atvoz1-1 atvoz2-1 correlated with increased expression of several FLC activators, including components of the PAF1 and SWR1 chromatin-modifying complexes. Additionally, AtVOZs were shown to bind the promoter of MOS3/SAR3 and directly regulate expression of this nuclear pore protein, which is known to participate in the regulation of flowering time, suggesting that AtVOZs exert at least some of their flowering regulation by influencing the nuclear pore function. Complementation of atvoz1-1 atvoz2-1 with AtVOZ2 reversed all double mutant phenotypes, confirming that the observed morphological and molecular changes arise from the absence of functional AtVOZ proteins, and validating the functional redundancy between AtVOZ1 and AtVOZ2.

  6. Selection of proper reference genes for the cyanobacterium Synechococcus PCC 7002 using real-time quantitative PCR.

    Science.gov (United States)

    Szekeres, Edina; Sicora, Cosmin; Dragoş, Nicolae; Drugă, Bogdan

    2014-10-01

    Synechococcus sp. PCC 7002 is known to be tolerant to most of the environmental factors in natural habitats of Cyanobacteria. Gene expression can be easily studied in this cyanobacterium, as its complete genome sequence is available. These properties make Synechococcus sp. PCC 7002 an appropriate model organism for biotechnological applications. To study the gene expression in Cyanobacteria, real-time quantitative PCR (qPCR) can be used, but as this is a highly sensitive method, data standardization is indicated between samples. The most commonly used strategy is normalization against internal reference genes. Synechococcus sp. PCC 7002 has not yet been evaluated for the best reference genes. In this work, six candidate genes were analyzed for this purpose. Cyanobacterial cultures were exposed to several stress conditions, and three different algorithms were used for ranking the reference genes: geNorm, NormFinder, and BestKeeper. Moreover, gene expression stability value M and single-control normalization error E were calculated. Our data provided a list of reference genes that can be used in qPCR experiments in Synechococcus sp. PCC 7002. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  7. Processing and properties of advanced metallic foams

    Science.gov (United States)

    Brothers, Alan Harold

    Since the development of the first aluminum foams in the middle of the 20th century [178], great advances have been made in the processing and fundamental understanding of metallic foams. As a result of these advances, metallic foams are now penetrating a number of applications where their unique suite of properties makes them superior to solid materials, such as lightweight structures, packaging and impact protection, and filtration and catalysis [3]. The purpose of this work is to extend the use of metallic foams in such applications by expanding their processing to include more sophisticated base alloys and architectures. The first four chapters discuss replacement of conventional crystalline metal foams with ones made from high-strength, low-melting amorphous metals, a substitution that offers potential for achieving mechanical properties superior to those of the best crystalline metal foams, without sacrificing the simplicity of processing methods made for low-melting crystalline alloys. Three different amorphous metal foams are developed in these chapters, and their structures and properties characterized. It is shown for the first time that amorphous metal foams, due to stabilization of shear bands during bending of their small strut-like features, are capable of compressive ductility comparable to that of ductile crystalline metal foams. A two-fold improvement in mechanical energy absorption relative to crystalline aluminum foams is shown experimentally to result from this stabilization. The last two chapters discuss modifications in foam processing that are designed to introduce controllable and continuous gradients in local foam density, which should improve mass efficiency by mimicking the optimized structures found in natural cellular materials [64], as well as facilitate the bonding and joining of foams with solid materials in higher-order structures. Two new processing methods are developed, one based on replication of nonuniformly-compressed polymer

  8. 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.

  9. Enthalpy-based multiple-relaxation-time lattice Boltzmann method for solid-liquid phase-change heat transfer in metal foams.

    Science.gov (United States)

    Liu, Qing; He, Ya-Ling; Li, Qing

    2017-08-01

    In this paper, an enthalpy-based multiple-relaxation-time (MRT) lattice Boltzmann (LB) method is developed for solid-liquid phase-change heat transfer in metal foams under the local thermal nonequilibrium (LTNE) condition. The enthalpy-based MRT-LB method consists of three different MRT-LB models: one for flow field based on the generalized non-Darcy model, and the other two for phase-change material (PCM) and metal-foam temperature fields described by the LTNE model. The moving solid-liquid phase interface is implicitly tracked through the liquid fraction, which is simultaneously obtained when the energy equations of PCM and metal foam are solved. The present method has several distinctive features. First, as compared with previous studies, the present method avoids the iteration procedure; thus it retains the inherent merits of the standard LB method and is superior to the iteration method in terms of accuracy and computational efficiency. Second, a volumetric LB scheme instead of the bounce-back scheme is employed to realize the no-slip velocity condition in the interface and solid phase regions, which is consistent with the actual situation. Last but not least, the MRT collision model is employed, and with additional degrees of freedom, it has the ability to reduce the numerical diffusion across the phase interface induced by solid-liquid phase change. Numerical tests demonstrate that the present method can serve as an accurate and efficient numerical tool for studying metal-foam enhanced solid-liquid phase-change heat transfer in latent heat storage. Finally, comparisons and discussions are made to offer useful information for practical applications of the present method.

  10. Enthalpy-based multiple-relaxation-time lattice Boltzmann method for solid-liquid phase-change heat transfer in metal foams

    Science.gov (United States)

    Liu, Qing; He, Ya-Ling; Li, Qing

    2017-08-01

    In this paper, an enthalpy-based multiple-relaxation-time (MRT) lattice Boltzmann (LB) method is developed for solid-liquid phase-change heat transfer in metal foams under the local thermal nonequilibrium (LTNE) condition. The enthalpy-based MRT-LB method consists of three different MRT-LB models: one for flow field based on the generalized non-Darcy model, and the other two for phase-change material (PCM) and metal-foam temperature fields described by the LTNE model. The moving solid-liquid phase interface is implicitly tracked through the liquid fraction, which is simultaneously obtained when the energy equations of PCM and metal foam are solved. The present method has several distinctive features. First, as compared with previous studies, the present method avoids the iteration procedure; thus it retains the inherent merits of the standard LB method and is superior to the iteration method in terms of accuracy and computational efficiency. Second, a volumetric LB scheme instead of the bounce-back scheme is employed to realize the no-slip velocity condition in the interface and solid phase regions, which is consistent with the actual situation. Last but not least, the MRT collision model is employed, and with additional degrees of freedom, it has the ability to reduce the numerical diffusion across the phase interface induced by solid-liquid phase change. Numerical tests demonstrate that the present method can serve as an accurate and efficient numerical tool for studying metal-foam enhanced solid-liquid phase-change heat transfer in latent heat storage. Finally, comparisons and discussions are made to offer useful information for practical applications of the present method.

  11. Making continuous bubble type polyethylene foam incombustible

    International Nuclear Information System (INIS)

    Kaji, Kanako; Hatada, Motoyoshi; Yoshizawa, Iwao; Komai, Kuniaki; Kohara, Choji.

    1989-01-01

    Since continuous bubble type plastic foam has excellent compression characteristics and sound absorption characteristics, it has been widely used as cushion material, sealing material, sound insulating material and so on. However, the most part of plastic foam is taken by air, therefore at the time of fires, it becomes a very dangerous material. At present, the material used mostly as the seat cushions for airliners, railroad coaches, automobiles and others is polyurethane foam, but since it contains C-N couples in its molecules, it is feared to generate cyanic gas according to the condition of combustion. As the plastic foam that does not generate harmful gas at the time of fires, there is continuous bubble type polyethylene which is excellent in its weathering property and chemical resistance. A reactive, phosphorus-containing oligomer has large molecular weight and two or more double couplings in a molecule, therefore, it does not enter the inside of polyethylene, and polymerizes and crosslinks on the surfaces of bubble walls in the foam, accordingly it is expected that the apparent graft polymerization is carried out, and it is very effective for making polyethylene foam incombustible. The method of making graft foam, the properties of graft foam and so on are reported. When the graft polymerization of this oligomer to continuous bubble type polyethylene foam was tried, highly incombustible polyethylene foam was obtained. (K.I.)

  12. AC induction field heating of graphite foam

    Science.gov (United States)

    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.

  13. Foam relaxation in fractures and narrow channels

    Science.gov (United States)

    Lai, Ching-Yao; Rallabandi, Bhargav; Perazzo, Antonio; Stone, Howard A.

    2017-11-01

    Various applications, from foam manufacturing to hydraulic fracturing with foams, involve pressure-driven flow of foams in narrow channels. We report a combined experimental and theoretical study of this problem accounting for the compressible nature of the foam. In particular, in our experiments the foam is initially compressed in one channel and then upon flow into a second channel the compressed foam relaxes as it moves. A plug flow is observed in the tube and the pressure at the entrance of the tube is higher than the exit. We measure the volume collected at the exit of the tube, V, as a function of injection flow rate, tube length and diameter. Two scaling behaviors for V as a function of time are observed depending on whether foam compression is important or not. Our work may relate to foam fracturing, which saves water usage in hydraulic fracturing, more efficient enhanced oil recovery via foam injection, and various materials manufacturing processes involving pressure-driven flow foams.

  14. Covering sources of toxic vapors with foam

    International Nuclear Information System (INIS)

    Aue, W. P.; Guidetti, F.

    2009-01-01

    In a case of chemical terrorism, first responders might well be confronted with a liquid source of toxic vapor which keeps spreading out its hazardous contents. With foam as an efficient and simple means, such a source could be covered up in seconds and the spread of vapors mitigated drastically. Once covered, the source could then wait for a longer time to be removed carefully and professionally by a decontamination team. In order to find foams useful for covering up toxic vapor sources, a large set of measurements has been performed in order to answer the following questions: - Which foams could be used for this purpose? - How thick should the foam cover be? - For how long would such a foam cover be effective? - Could the practical application of foam cause a spread of the toxic chemical? The toxic vapors sources included GB, GD and HD. Among the foams were 10 fire fighter foams (e.g. AFFF, protein) and the aqueous decontamination foam CASCAD. Small scale experiments showed that CASCAD is best suited for covering a toxic source; a 10 cm layer of it covers and decontaminates GB. The large scale experiments confirmed that any fire fighter foam is a suitable cover for a longer or shorter period.(author)

  15. 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.

  16. Crosslinked polyethylene foams, via eb radiation

    International Nuclear Information System (INIS)

    Cardoso, E.C.L.; Lugao, A. B.; Andrade e Silva, L. G.

    1998-01-01

    Polyethylene foams, produced by radio-induced crosslinking, show a smooth and homogeneous surface, when compared to chemical crosslinking method using peroxide as crosslinking agent. This process fosters excellent adhesive and printability properties. Besides that, closed cells, intrinsic to these foams, imparts optimum mechanical, shocks and insulation resistance, indicating these foams to some markets segments as: automotive and transport; buoyancy, flotation and marine; building and insulation; packaging; domestic sports and leisure goods. We were in search of an ideal foam, by adding 5 to 15% of blowing agent in LDPE. A series of preliminary trials defined 203 degree sign C as the right blowing agent decomposition temperature. At a 22.7 kGys/dose ratio, the lowest dose for providing an efficient foam was 30 kGy, for a formulation comprising 10% of azodicarbonamide in LDPE, within a 10 minutes foaming time

  17. 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.

  18. Theoretical Evaluation of Foam Proppant Carriers

    Science.gov (United States)

    von Holt, H.; Kam, S.; Williams, W. C.

    2017-12-01

    Hydraulic fracturing in oil wells results in a large amount of produced water which must be properly disposed of and is currently a key environmental issue preventing further development in US domestic oil and gas production. The primary function of this liquid is to carry particulates, a.k.a. Proppant, into the stress fractures in order to hold open a pathway in which petroleum can flow into the wellbore. A potential superior technique is to use foam instead of liquid; liquids rely on turbulence to suspend proppant while foams carry particulates on the surfaces. Therefore, foams can carry more proppant deeper into the fractures while typically using 50%-90% less liquid, depending on foam quality. This comparative analysis uses the vorticity equation for a liquid to approximate the base case of particle suspension. This is then compared to a multitude of foam transport models in order to demonstrate the efficacy of foams when used in hydraulic fracturing. This work serves as the basis for future laboratory and hopefully field scale studies of foam proppant carriers.

  19. 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.

  20. 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.

  1. 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,

  2. The Effect of Platelet-Rich Plasma on Survival of the Composite Graft and the Proper Time of Injection in a Rabbit Ear Composite Graft Model

    Directory of Open Access Journals (Sweden)

    Hyun Nam Choi

    2014-11-01

    Full Text Available BackgroundAdministration of growth factors has been associated with increased viability of composite grafts greater than 1-cm in diameter. Platelet-rich plasma (PRP contains many of the growth factors studied. In this study, we evaluate the effect of PRP injection on composite graft viability and the proper time for injection.MethodsA total of 24 New Zealand White rabbits were divided into four groups. Autologous PRP was injected into the recipient sites three days before grafting in group 1, on the day of grafting in group 2, and three days after grafting in group 3. Group 4 served as control without PRP administration. Auricular composite grafts of 3-cm diameter were harvested and grafted back into place after being rotated 180 degrees. Median graft viability and microvessel density were evaluated at day 21 of graft via macroscopic photographs and immunofluorescent staining, respectively.ResultsThe median graft survival rate was 97.8% in group 1, 69.2% in group 2, 55.7% in group 3, and 40.8% in the control group. The median vessel counts were 34 (per ×200 HPF in group 1, 24.5 in group 2, 19.5 in group 3, and 10.5 in the control group.ConclusionsThis study demonstrates that PRP administration is associated with increased composite graft viability. All experimental groups showed a significantly higher survival rate and microvessel density, compared with the control group. Pre-administration of PRP was followed by the highest graft survival rate and revascularization. PRP treatments are minimally invasive, fast, easily applicable, and inexpensive, and offer a potential clinical pathway to larger composite grafts.

  3. Principles of Proper Validation

    DEFF Research Database (Denmark)

    Esbensen, Kim; Geladi, Paul

    2010-01-01

    Validation in chemometrics is presented using the exemplar context of multivariate calibration/prediction. A phenomenological analysis of common validation practices in data analysis and chemometrics leads to formulation of a set of generic Principles of Proper Validation (PPV), which is based...

  4. Foam pad of appropriate thickness can improve diagnostic value of foam posturography in detecting postural instability.

    Science.gov (United States)

    Liu, Bo; Leng, Yangming; Zhou, Renhong; Liu, Jingjing; Liu, Dongdong; Liu, Jia; Zhang, Su-Lin; Kong, Wei-Jia

    2017-11-21

    The present study investigated the effect of foam thickness on postural stability in patients with unilateral vestibular hypofunction (UVH) during foam posturography. Static and foam posturography were performed in 33 patients (UVH group) and 30 healthy subjects (control group) with eyes open (EO) and closed (EC) on firm surface and on 1-5 foam pad(s). Sway velocity (SV) of center of pressure, standing time before falling (STBF) and falls reaction were recorded and analyzed. (1) SVs had an increasing tendency in both groups as the foam pads were added under EO and EC conditions. (2) STBFs, only in UVH group with EC, decreased with foam thickness increasing. (3) Significant differences in SV were found between the control and UVH group with EO (except for standing on firm surface, on 1 and 2 foam pad(s)) and with EC (all surface conditions). (4) Receiver operating characteristic curve analysis showed that the SV could better reflect the difference in postural stability between the two groups while standing on the 4 foam pads with EC. Our study showed that diagnostic value of foam posturography in detecting postural instability might be enhanced by using foam pad of right thickness.

  5. 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.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    We prepared foam glasses from cathode-ray-tube panel glass and CaCO3 as a foaming agent. We investigated the influences of powder preparation, CaCO3 concentration and foaming temperature and time on the density, porosity and homogeneity of the foam glasses. The results show that the decomposition...... kinetics of CaCO3 has a strong influence on the foaming process. The decomposition temperature can be modified by varying the milling time of the glass–CaCO3 mixture and thus for a specific CaCO3 concentration an optimum milling time exists, at which a minimum in density and a homogeneous closed porosity...

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

    DEFF Research Database (Denmark)

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

    2012-01-01

    of the simulation contributes to more precise planning of the schedule of water and gas injection, prediction of the injection results and evaluation of the method efficiency. The testing of the surfactant properties allows making grounded choice of surfactant to use. The analysis of the history match gives insight...... foam model was tested with sensitivity analysis on foam properties to provide a guideline for the history matching process (GOR alteration) of FAWAG Pilot of Snorre Field (Statoil). The aim was to check the authenticity of presented new foam model in commercial software whether it is implementable...... of the fluid flows control inside reservoir. The way; how specific properties control the time of gas arrival and values of GOR are described. The analyses of the improvements in the injection schedule are shown. With increasing number of CO2 and FAWAG methods in preparation worldwide, the use...

  8. 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.

  9. Foam engineering fundamentals and applications

    CERN Document Server

    2012-01-01

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

  10. 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.

  11. "Grinding" cavities in polyurethane foam

    Science.gov (United States)

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

    1980-01-01

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

  12. 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

  13. Decontamination of radionuclide strontium polluted the analog instruments surface by high stable foam

    International Nuclear Information System (INIS)

    Zhu Gaolong; Chen Shuai; Lin Xiaoyan; Luo Xuegang

    2014-01-01

    Decontamination of the radionuclide strontium polluted the analog instruments surface radionuclide strontium by foam, where the high stable foam detergent was prepared by Sodium dodecylbenzene sulfonate (SDBS) as a foaming agent and hydroxyethyl cellulose (HEC) as a foam stabilizer. The effects of adding a foam stabilizer hydroxyethyl cellulose (HEC) on foam stability and the volume of drainage liquid were discussed and contact time, foaming agent concentration, temperature, humidity on foam decontamination efficiency of the analog instruments surface by radionuclide strontium were observed. The results show that there has been a significant increase of foam stability with the increase of HEC addition, the volume of drainage liquid was decrease from 7.8 g to 0 g and the half decay time of foam was extended from 305 seconds to 1050 seconds after the HEC addition increase from 0 % to 3%. The half decay time increase with the continue to increase of HEC addition but decrease of the foamability. The foam drainage speed up with the increase of temperture, the foam will burst rapidly when the temperture is higer than 600 ℃. The high table foam has a effective decontamination efficiency between 88%∼95%. contact time, foaming agent concentration, humidity do not much affect on the foam decontamination. In order to reduce the affect of volume of drainage liquid on the precision instrument, the contact time should control in 3 min. (authors)

  14. Proper Islamic Consumption

    DEFF Research Database (Denmark)

    Fischer, Johan

    '[T]his book is an excellent study that is lucidly written, strongly informed by theory, rich in ethnography, and empirically grounded. It has blazed a new trail in employing the tools of both religious studies and cultural studies to dissect the complex subject of “proper Islamic consumption...... mobile, religiously committed communities to the opportunities and perils presented by modernisation. It also tells us something about the debates concerning the meanings and practices of Islam within an aggressive, globalised, secularised modernity. In Malaysia this is an especially intriguing issue...... because it is the Malay‐dominated state which has been crucial in generating and shaping a particular kind of modernity in order to address the problems posed for nation‐building by a quite radical form of ethnic pluralism.' Reviewed by V.T. (Terry) King, University of Leeds, ASEASUK News 46, 2009   'In...

  15. Positivity of spin foam amplitudes

    International Nuclear Information System (INIS)

    Baez, John C; Christensen, J Daniel

    2002-01-01

    The amplitude for a spin foam in the Barrett-Crane model of Riemannian quantum gravity is given as a product over its vertices, edges and faces, with one factor of the Riemannian 10j symbols appearing for each vertex, and simpler factors for the edges and faces. We prove that these amplitudes are always nonnegative for closed spin foams. As a corollary, all open spin foams going between a fixed pair of spin networks have real amplitudes of the same sign. This means one can use the Metropolis algorithm to compute expectation values of observables in the Riemannian Barrett-Crane model, as in statistical mechanics, even though this theory is based on a real-time (e iS ) rather than imaginary-time e -S path integral. Our proof uses the fact that when the Riemannian 10j symbols are nonzero, their sign is positive or negative depending on whether the sum of the ten spins is an integer or half-integer. For the product of 10j symbols appearing in the amplitude for a closed spin foam, these signs cancel. We conclude with some numerical evidence suggesting that the Lorentzian 10j symbols are always nonnegative, which would imply similar results for the Lorentzian Barrett-Crane model

  16. High temperature adhesive silicone foam composition, foam generating system and method of generating foam. [For access denial

    Science.gov (United States)

    Mead, J.W.; Montoya, O.J.; Rand, P.B.; Willan, V.O.

    1983-12-21

    Access to a space is impeded by generation of a sticky foam from a silicone polymer and a low boiling solvent such as a halogenated hydrocarbon. In a preferred aspect, the formulation is polydimethylsiloxane gel mixed with F502 Freon as a solvent and blowing agent, and pressurized with CO/sub 2/ in a vessel to about 250 PSI, whereby when the vessel is opened, a sticky and solvent resistant foam is deployed. The foam is deployable, over a wide range of temperatures, adhering to wet surfaces as well as dry, is stable over long periods of time and does not propagate flame or lose adhesive properties during an externally supported burn.

  17. Experimental Investigations of Space Shuttle BX-265 Foam

    Science.gov (United States)

    Lerch, Bradley A.; Sullivan, Roy M.

    2009-01-01

    This report presents a variety of experimental studies on the polyurethane foam, BX-265. This foam is used as a close-out foam insulation on the space shuttle external tank. The purpose of this work is to provide a better understanding of the foam s behavior and to support advanced modeling efforts. The following experiments were performed: Thermal expansion was measured for various heating rates. The in situ expansion of foam cells was documented by heating the foam in a scanning electron microscope. Expansion mechanisms are described. Thermogravimetric analysis was performed at various heating rates and for various environments. The glass transition temperature was also measured. The effects of moisture on the foam were studied. Time-dependent effects were measured to give preliminary data on viscoelastoplastic properties.

  18. Microcellular foam injection molding with cellulose nanofibers (CNFs)

    Science.gov (United States)

    Ohshima, Masahiro; Kubota, Masaya; Ishihara, Shota; Hikima, Yuta; Sato, Akihiro; Sekiguchi, Takafumi

    2016-03-01

    Cellulose nanofibers (CNFs) nanocomposites polypropylene foams are prepared by microcellular foam injection molding with core-back operation. The modified CNFs were blended with isotactic-polypropylene (i-PP) at different CNFs weight percentages and foamed to investigate the effect of CNFs on cell morphology. CNFs in i-PP increased the elastic modulus and induced a strain hardening behavior. CNFs also shifted the crystallization temperature of i-PP to higher temperature and enhanced crystallization. With these changes in rheological and thermal properties, CNFs could reduce the cell size and increase the cell density of the foams. By adjusting the core-back timing i.e., foaming temperature, the closed cell and the nano-fibrillated open cellular structure could be produced. The flexural modulus and bending strength of foams were measured by three point flexural tester. The flexural modulus and bending strength were increased as the CNFs content in i-PP was increased at any foam expansion ratio.

  19. 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...

  20. Flexible Foam Model.

    Energy Technology Data Exchange (ETDEWEB)

    Neilsen, Michael K.; Lu, Wei-Yang; Werner, Brian T.; Scherzinger, William M.; Lo, Chi S.

    2018-03-01

    Experiments were performed to characterize the mechanical response of a 15 pcf flexible polyurethane foam to large deformation at different strain rates and temperatures. Results from these experiments indicated that at room temperature, flexible polyurethane foams exhibit significant nonlinear elastic deformation and nearly return to their original undeformed shape when unloaded. However, when these foams are cooled to temperatures below their glass transition temperature of approximately -35 o C, they behave like rigid polyurethane foams and exhibit significant permanent deformation when compressed. Thus, a new model which captures this dramatic change in behavior with temperature was developed and implemented into SIERRA with the name Flex_Foam to describe the mechanical response of both flexible and rigid foams to large deformation at a variety of temperatures and strain rates. This report includes a description of recent experiments. Next, development of the Flex Foam model for flexible polyurethane and other flexible foams is described. Selection of material parameters are discussed and finite element simulations with the new Flex Foam model are compared with experimental results to show behavior that can be captured with this new model.

  1. 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.

  2. 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.

  3. Foam Flows in Analog Porous Media

    Science.gov (United States)

    Meheust, Y.; Géraud, B.; Jones, S. A.; Cantat, I.; Dollet, B.

    2015-12-01

    Foams have been used for decades as displacing fluids for EOR and aquifer remediation, and more recently as carriers of chemical amendments for the remediation of the vadose zone. Apart from various interesting physico-chemical and biochemical properties, foams are better injection fluids due to their low sensitivity to gravity and their peculiar rheology: for foams with bubbles on the order of at least the typical pore size, viscous dissipation arises mostly from the contact zones between the soap films and the walls. In most experimental studies no local information of the foam structure is possible, and only global quantities such as the effective viscosity can be measured. We investigate foam flow through a two-dimensional porous medium consisting of circular obstacles positioned randomly in a horizontal transparent Hele-Shaw cell. The local foam structure is recorded in situ, which provides a measure of the spatial distribution of bubble velocities and sizes at regular time intervals. The flow exhibits a rich phenomenology including preferential flow paths and local flow intermittency/non-stationarity despite the imposed permanent global flow rate. Moreover, the medium selects the bubble size distribution through lamella division-triggered bubble fragmentation. Varying the mean bubble size of the injected foam, its water content, and mean velocity, we characterize those processes systematically and show that the distributions of bubble sizes and velocities are to some extent correlated. We furthermore measure the evolution, along the flow direction, of the distribution of bubble sizes, and measure the efficiency of bubble fragmentation as a function of the control parameters. The bubble fragmentation can be modeled numerically and to some extent analytically, based on statistical measures inferred from the experimental data. This study sheds new light on the local rheology of foams in porous media and opens the way towards quantitative characterization of the

  4. 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

  5. Micromodel foam flow study

    Energy Technology Data Exchange (ETDEWEB)

    Chambers, K.T.; Radke, C.J.

    1990-10-01

    Foams are often utilized as part of enhanced oil recovery techniques. This report presents the results of a micromodel foam flow study. Micromodels are valuable tools in uncovering capillary phenomena responsible for lamellae generation and coalescence during foam flow in porous media. Among the mechanisms observed are snap-off, weeping-flow breakup, and lamella division and leave behind. Coalescence mechanisms include dynamic capillary-pressure-induced lamella drainage and gas diffusion. These phenomena are sensitive to the mode of injection, the local capillary environment, and the geometry of the pore structure. An important consideration in presenting a tractable model of foam flow behavior is the ability to identify the pore-level mechanisms having the greatest impact on foam texture. The predominant mechanisms will vary depending upon the application for foam as an enhanced oil recovery (EOR) fluid. Both simultaneous gas and surfactant injection and surfactant alternating with gas injection (SAG) have been used to create foam for mobility control in EOR projects. The model developed is based on simultaneous gas and surfactant injection during steady-state conditions into a Berea sandstone core. The lamellae generation and coalescence mechanisms included in this model are snap-off, lamella division, and dynamic capillary-pressure-induced lamella drainage. This simplified steady-state model serves as a foundation for developing more complete rate expressions and for extending the population balance to handle transient foam flow behavior. 70 refs., 30 figs.

  6. Stability of Decontamination Foam Containing Silica Nanoparticles and Viscosifier

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, In Ho; Jung, Chong Hun; Yoon, Suk Bon; Kim, Chorong; Jung, Jun Young; Park, Sang Yoon; Moon, Jei Kwon; Choi, Wang Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    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, foam is a good material for in situ decontamination because it generates low final waste volumes owing to its volume expansion. 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. The decontamination efficiency can be enhanced by improving the contact time between chemical reagents and a contaminated surface through the addition of surfactants and viscosifiers into the decontamination foam. The objective of this study is to investigate the effect of silica nanoparticles and a viscosifier on the foam stability and the dissolution behaviors of corroded specimens using a non-ionic surfactant. This study showed the effect of viscosifiers and nanoparticles on the foam stability when developing new formulations of decontamination foam. The addition of xanthan gum and the mixture of xanthan gum and silica nanoparticles (M-5) significantly increased the foam stability, compared to the surfactant solution alone. This result indicates that both the viscosifier and nanoparticles have a synergistic effect on the foam stability. As the contact time increased, the dissolution rate increased to become similar to the dissolution that contained decontamination liquid.

  7. Formation fracturing with foam

    Energy Technology Data Exchange (ETDEWEB)

    Blauer, R.E.; Kohlhaas, C.A.

    1974-01-01

    Over 60 wells have been treated with hydraulic fracturing techniques, with foam as the fracturing fluid. These foams contained as much as 95% gaseous phase; most treatments used foams with gas contents in the 65% to 85% range. Foam has several desirable properties for use as a fracturing fluid: high sand-carrying and sand-suspending capability, low fluid loss, low hydrostatic head, low pressure drops due to friction, quick fluid recovery, low formation damage, and no reduction of fracture conductivity due to fluid ingredients. Most applications of foam as a fracturing fluid have been in low permeability gas reservoirs. However, several oil reservoirs also have been successfully treated. Cost of the treatment is approx. the same or slightly less than a treatment with conventional fluids of comparable volume and rate. (25 refs.)

  8. Space Motions of the Dwarf Spheroidal Galaxies Draco and Sculptor Based on HST Proper Motions with a ˜10 yr Time Baseline

    Science.gov (United States)

    Sohn, Sangmo Tony; Patel, Ekta; Besla, Gurtina; van der Marel, Roeland P.; Bullock, James S.; Strigari, Louis E.; van de Ven, Glenn; Walker, Matt G.; Bellini, Andrea

    2017-11-01

    We present new proper motion (PM) measurements of the dwarf spheroidal galaxies (dSphs) Draco and Sculptor using multiepoch images obtained with the Hubble Space Telescope ACS/WFC. Our PM results have uncertainties far lower than previous measurements, even those made with the same instrument. The PM results for Draco and Sculptor are ({μ }W, {μ }N{)}{Dra}=(-0.0562+/- 0.0099, -0.1765+/- 0.0100) {mas} {{yr}}-1 and ({μ }W, {μ }N{)}{Scl}=(-0.0296+/- 0.0209, -0.1358+/- 0.0214) {mas} {{yr}}-1. The implied Galactocentric velocity vectors for Draco and Sculptor have radial and tangential components: ({V}{rad}, {V}\\tan {)}{Dra}=(-88.6, 161.4)+/- (4.4, 5.6) {km} {{{s}}}-1 and ({V}{rad}, {V}\\tan {)}{Scl}=(72.6, 200.2)+/- (1.3, 10.8) {km} {{{s}}}-1. We study the detailed orbital histories of both Draco and Sculptor via numerical orbit integrations. Orbital periods of Draco and Sculptor are found to be 1-2 Gyr and 2-5 Gyr, respectively, accounting for uncertainties in the Milky Way (MW) mass. We also study the influence of the Large Magellanic Cloud (LMC) on the orbits of Draco and Sculptor. Overall, the inclusion of the LMC increases the scatter in the orbital results. Based on our calculations, Draco shows a rather wide range of orbital parameters depending on the MW mass and inclusion/exclusion of the LMC, but Sculptor’s orbit is very well constrained, with its most recent pericentric approach to the MW being 0.3-0.4 Gyr ago. Our new PMs imply that the orbital trajectories of both Draco and Sculptor are confined within the “Disk of Satellites,” better so than implied by earlier PM measurements, and likely rule out the possibility that these two galaxies were accreted together as part of a tightly bound group.

  9. The Modification of Polyurethane Foams Using New Boroorganic Polyols (II) Polyurethane Foams from Boron-Modified Hydroxypropyl Urea Derivatives

    Science.gov (United States)

    2014-01-01

    The work focuses on research related to determination of application possibility of new, ecofriendly boroorganic polyols in rigid polyurethane foams production. Polyols were obtained from hydroxypropyl urea derivatives esterified with boric acid and propylene carbonate. The influence of esterification type on properties of polyols and next on polyurethane foams properties was determined. Nitrogen and boron impacts on the foams' properties were discussed, for instance, on their physical, mechanical, and electric properties. Boron presence causes improvement of dimensional stability and thermal stability of polyurethane foams. They can be applied even at temperature 150°C. Unfortunately, introducing boron in polyurethanes foams affects deterioration of their water absorption, which increases as compared to the foams that do not contain boron. However, presence of both boron and nitrogen determines the decrease of the foams combustibility. Main impact on the decrease combustibility of the obtained foams has nitrogen presence, but in case of proper boron and nitrogen ratio their synergic activity on the combustibility decrease can be easily seen. PMID:24587721

  10. Hydraulic Properties of Porous Media Saturated with Nanoparticle-Stabilized Air-Water Foam

    Directory of Open Access Journals (Sweden)

    Xianglei Zheng

    2016-12-01

    Full Text Available The foam generated by the mixture of air and water has a much higher viscosity and lower mobility than those of pure water or gas that constitutes the air-water foam. The possibility of using the air-water foam as a flow barrier for the purpose of groundwater and soil remediation is explored in this paper. A nanoparticle-stabilized air-water foam was fabricated by vigorously stirring the nano-fluid in pressurized condition. The foam bubble size distribution was analyzed with a microscope. The viscosities of foams generated with the solutions with several nanoparticle concentrations were measured as a function of time. The breakthrough pressure of foam-saturated microfluidic chips and sand columns were obtained. The hydraulic conductivity of a foam-filled sand column was measured after foam breakthrough. The results show that: (1 bubble coalescence and the Ostwald ripening are believed to be the reason of bubble size distribution change; (2 the viscosity of nanoparticle-stabilized foam and the breakthrough pressures decreased with time once the foam was generated; (3 the hydraulic conductivity of the foam-filled sand column was almost two orders of magnitude lower than that of a water-saturated sand column even after the foam-breakthrough. Based on the results in this study, the nanoparticle-stabilized air-water foam could be injected into contaminated soils to generate vertical barriers for temporary hydraulic conductivity reduction.

  11. Optimisation of Sintering Factors of Titanium Foams Using Taguchi Method

    OpenAIRE

    S. Ahmad; N. Muhamad; J. Sahari; K. R. Jamaludin

    2010-01-01

    Metal foams have the potential to be used in the production of bipolar plates in Polymer Electron Membrane Fuel Cells (PEMFC). In this paper, pure titanium was used to prepare titanium foam using the slurry method. The electrical conductivity is the most important parameter to be considered in the production of good bipolar plates. To achieve a high conductivity of the titanium foam, the effects of various parameters including temperature, time profile and composition have to be characterised...

  12. Anaerobic digestion foaming in full-scale biogas plants: A survey on causes and solutions

    DEFF Research Database (Denmark)

    Kougias, Panagiotis; Boe, Kanokwan; O-Thong, Sompong

    2014-01-01

    Anaerobic digestion foaming is a common operation problem in biogas plants with negative impacts on the biogas plants economy and environment. A survey of 16 Danish full-scale biogas plants on foaming problems revealed that most of them had experienced foaming in their processes up to three times...... of foaming in this case. Moreover, no difference in bacterial communities between the foaming and non-foaming reactors was observed, showing that filamentous bacteria were not the main reason for foaming in this case. © IWA Publishing 2014....... per year. Foaming incidents often lasted from one day to three weeks, causing 20-50% biogas production loss. One foaming case at Lemvig biogas plant has been investigated and the results indicated that the combination of feedstock composition and mixing pattern of the reactor was the main cause...

  13. Rheology of liquid foam

    International Nuclear Information System (INIS)

    Hoehler, R; Cohen-Addad, S

    2005-01-01

    Liquid foams can behave like solids or liquids, depending on the applied stress and on the experimental timescale. Understanding the origin of this complex rheology which gives rise to many applications and which resembles that of many other forms of soft condensed matter made of closely packed soft units requires challenging theoretical questions to be solved. We briefly recall the basic physics and physicochemistry of foams and review the experiments, numerical simulations and theoretical models concerning foam rheology published in recent years. (topical review)

  14. Kelvin's ideal foam structure

    International Nuclear Information System (INIS)

    Weaire, Denis

    2009-01-01

    Among his many extraordinary accomplishments, Kelvin was a pioneer of crystallography, elasticity and materials science. These interests came together to inspire his speculation on the nature of the ether in 1887. He conceived it to be an ordered liquid foam, of minimal surface area. Kelvin's ideal structure of foam has been realised in the laboratory only recently. In the meantime it was surpassed (in terms of surface area minimisation) by the Weaire-Phelan foam, which is the basis for one of the main buildings of the Beijing Olympics.

  15. Coarsening of firefighting foams containing fluorinated hydrocarbon surfactants

    Science.gov (United States)

    Kennedy, Matthew J.; Dougherty, John A.; Otto, Nicholas; Conroy, Michael W.; Williams, Bradley A.; Ananth, Ramagopal; Fleming, James W.

    2013-03-01

    Diffusion of gas between bubbles in foam causes growth of large bubbles at the expense of small bubbles and leads to increasing mean bubble size with time thereby affecting drainage. Experimental data shows that the effective diffusivity of nitrogen gas in aqueous film forming foam (AFFF), which is widely used in firefighting against burning liquids, is several times smaller than in 1% sodium dodecyl sulfate (SDS) foam based on time-series photographs of bubble size and weighing scale recordings of liquid drainage. Differences in foam structure arising from foam production might contribute to the apparent difference in the rates of coarsening. AFFF solution produces wetter foam with initially smaller bubbles than SDS solution due in part to the lower gas-liquid surface tension provided by the fluorosurfactants present in AFFF. Present method of foam production generates microbubble foam by high-speed co-injection of surfactant solution and gas into a tube of 3-mm diameter. These results contribute to our growing understanding of the coupling between foam liquid fraction, bubble size, surfactant chemistry, and coarsening. NRC Resident Research Associate at NRL

  16. 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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Vegetable-origin foam employed in dye extraction in tanning and leather processing facilities

    Directory of Open Access Journals (Sweden)

    José M. Cangemi

    2009-01-01

    Full Text Available This study addressed the use of conventional and vegetable origin polyurethane foams to extract C. I. Acid Orange 61 dye. The quantitative determination of the residual dye was carried out with an UV/Vis absorption spectrophotometer. The extraction of the dye was found to depend on various factors such as pH of the solution, foam cell structure, contact time and dye and foam interactions. After 45 days, better results were obtained for conventional foam when compared to vegetable foam. Despite presenting a lower percentage of extraction, vegetable foam is advantageous as it is considered a polymer with biodegradable characteristics.

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

    Directory of Open Access Journals (Sweden)

    M. Antunes

    2010-01-01

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

  19. Release of CFC-11 from disposal of polyurethane foam waste

    DEFF Research Database (Denmark)

    Kjeldsen, Peter; Jensen, M.H.

    2001-01-01

    The halocarbon CFC-11 has extensively been used as a blowing agent for polyurethane (PUR) insulation foams in home appliances and for residential and industrial construction. Release of CFCs is an important factor in the depletion of the ozone layer. For CFC-11 the future atmospheric concentrations...... will mainly depend on the continued release from PUR foams. Little is known about rates and time frames of the CFC release from foams especially after treatment and disposal of foam containing waste products. The CFC release is mainly controlled by slow diffusion out through the PUR. From the literature...

  20. All in Its Proper Time: Monitoring the Emergence of a Memory Bias for Novel, Arousing-Negative Words in Individuals with High and Low Trait Anxiety

    Science.gov (United States)

    Eden, Annuschka Salima; Zwitserlood, Pienie; Keuper, Katharina; Junghöfer, Markus; Laeger, Inga; Zwanzger, Peter; Dobel, Christian

    2014-01-01

    The well-established memory bias for arousing-negative stimuli seems to be enhanced in high trait-anxious persons and persons suffering from anxiety disorders. We monitored the emergence and development of such a bias during and after learning, in high and low trait anxious participants. A word-learning paradigm was applied, consisting of spoken pseudowords paired either with arousing-negative or neutral pictures. Learning performance during training evidenced a short-lived advantage for arousing-negative associated words, which was not present at the end of training. Cued recall and valence ratings revealed a memory bias for pseudowords that had been paired with arousing-negative pictures, immediately after learning and two weeks later. This held even for items that were not explicitly remembered. High anxious individuals evidenced a stronger memory bias in the cued-recall test, and their ratings were also more negative overall compared to low anxious persons. Both effects were evident, even when explicit recall was controlled for. Regarding the memory bias in anxiety prone persons, explicit memory seems to play a more crucial role than implicit memory. The study stresses the need for several time points of bias measurement during the course of learning and retrieval, as well as the employment of different measures for learning success. PMID:24887093

  1. All in its proper time: monitoring the emergence of a memory bias for novel, arousing-negative words in individuals with high and low trait anxiety.

    Directory of Open Access Journals (Sweden)

    Annuschka Salima Eden

    Full Text Available The well-established memory bias for arousing-negative stimuli seems to be enhanced in high trait-anxious persons and persons suffering from anxiety disorders. We monitored the emergence and development of such a bias during and after learning, in high and low trait anxious participants. A word-learning paradigm was applied, consisting of spoken pseudowords paired either with arousing-negative or neutral pictures. Learning performance during training evidenced a short-lived advantage for arousing-negative associated words, which was not present at the end of training. Cued recall and valence ratings revealed a memory bias for pseudowords that had been paired with arousing-negative pictures, immediately after learning and two weeks later. This held even for items that were not explicitly remembered. High anxious individuals evidenced a stronger memory bias in the cued-recall test, and their ratings were also more negative overall compared to low anxious persons. Both effects were evident, even when explicit recall was controlled for. Regarding the memory bias in anxiety prone persons, explicit memory seems to play a more crucial role than implicit memory. The study stresses the need for several time points of bias measurement during the course of learning and retrieval, as well as the employment of different measures for learning success.

  2. Regular inhaled corticosteroids in adult-onset asthma and the risk for future cancer: a population-based cohort study with proper person-time analysis

    Directory of Open Access Journals (Sweden)

    Kok VC

    2015-03-01

    Full Text Available Victor C Kok,1,2 Jorng-Tzong Horng,2,3 Hsu-Kai Huang,3 Tsung-Ming Chao,4 Ya-Fang Hong5 1Division of Medical Oncology, Department of Internal Medicine, Kuang Tien General Hospital, Taichung, Taiwan; 2Department of Biomedical Informatics, Asia University Taiwan, Taichung, Taiwan; 3Department of Computer Science and Information Engineering, National Central University, Jhongli, Taiwan; 4Statistics Unit, Department of Applied Geomatics, Chien Hsin University, Jhongli, Taiwan; 5Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan Background: Recent studies have shown that inhaled corticosteroids (ICS can exert anti-inflammatory effects for chronic airway diseases, and several observational studies suggest that they play a role as cancer chemopreventive agents, particularly against lung cancer. We aimed to examine whether regular ICS use was associated with a reduced risk for future malignancy in patients with newly diagnosed adult-onset asthma. Methods: We used a population-based cohort study between 2001 and 2008 with appropriate person-time analysis. Participants were followed up until the first incident of cancer, death, or to the end of 2008. The Cox model was used to derive an adjusted hazard ratio (aHR for cancer development. Kaplan–Meier cancer-free survival curves of two groups were compared. Results: The exposed group of 2,117 regular ICS users and the nonexposed group of 17,732 non-ICS users were assembled. After 7,365 (mean, 3.5 years; standard deviation 2.1 and 73,789 (mean, 4.1 years; standard deviation 2.4 person-years of follow-up for the ICS users and the comparator group of non-ICS users, respectively, the aHR for overall cancer was nonsignificantly elevated at 1.33 with 95% confidence interval (CI, 1.00–1.76, P=0.0501. The Kaplan–Meier curves for overall cancer-free proportions of both groups were not significant (log-rank, P=0.065. Synergistic interaction of concurrent presence of regular ICS use was

  3. A modified Tessari method for producing more foam.

    Science.gov (United States)

    Xu, Jie; Wang, Yi-Fei; Chen, An-Wei; Wang, Tao; Liu, Shao-Hua

    2016-01-01

    This study aimed to develop a modified Tessari method for producing more sclerosing foam in treatment of extensive venous malformations. Sclerosing foam was produced by using Tessari method and the modified Tessari method. The procedure of the later was as follows: prepared foam in a sclerosant-air ratio of 1:4; connected three disposable 10 ml syringes to two medical three-way taps; drawn 4 ml of liquid sclerosant into one syringe and 16 ml averagely of air into the other two; then moved the plungers of all syringes back and forth for 20 times to produce sclerosing foam. The volume and foam half time (FHT) of foam produced by the two methods were compared. The average volume of sclerosing foam produced by Tessari method and the modified Tessari method were 9.8 and 19.7 ml, and assessed to have statistical difference. The FHT of foam produced by the two methods were 120 and 150 s, and assessed to have statistical difference. In conclusion, the modified Tessari method could produce more fresh and stable sclerosing foam.

  4. Ultralight metal foams.

    Science.gov (United States)

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

    2015-09-08

    Ultralight (battery electrodes; catalyst supports; and 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 εD 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.

  5. Auxetic Polyurethane Foam (Fabrication, Properties and Applications)

    International Nuclear Information System (INIS)

    Yousif, H.I.Y.

    2012-01-01

    Modern technology requires new materials of special properties. For the last two decades there has been a great interest in a class of materials known as auxetic materials. An auxetic material is a material that has a negative Poisson's ratio which means that this material expands laterally when they subjected to a tensile force unlike most of the other traditional materials. This material has superior properties over the traditional material such as high shear modulus and high impact resistance, which makes this material a good candidate for many engineering applications. In the present research work, auxetic flexible polyurethane polymeric foams having different densities were fabricated from conventional flexible polyurethane polymeric foam at different compression ratios. The microstructure of conventional and processed foams was examined by optical microscope to compare between the two structures. The microstructure of processed foam was compared with the one presented in the literature and it has shown the auxetic structure configuration. This is the first time to produce auxetic foam in Egypt. Conventional and auxetic foam samples having cylindrical and square cross-sections were produced from foams having different densities (25 kg/m 3 and 30 kg/m 3 ). The compression ratios used to produce the auxetic samples are (5.56, 6.94 and 9.26). Four mechanical tests were carried out to get the mechanical properties for both conventional and auxetic foams. Two quasi-static mechanical tests t ension and compression a nd two dynamic mechanical tests H ysteresis and resilience w ere carried out to compare between the conventional and auxetic foams. The quasi-static tensile test was carried out at speed was adjusted to be position control rate of 0.2 mm/s. The compression and hysteresis tests were carried out at strain control rate of 0.3 S -1 . The data recorded from the machine were stress and strain. The modulus of elasticity and Poisson's ratio of the test

  6. mdFoam+: Advanced molecular dynamics in OpenFOAM

    Science.gov (United States)

    Longshaw, S. M.; Borg, M. K.; Ramisetti, S. B.; Zhang, J.; Lockerby, D. A.; Emerson, D. R.; Reese, J. M.

    2018-03-01

    This paper introduces mdFoam+, which is an MPI parallelised molecular dynamics (MD) solver implemented entirely within the OpenFOAM software framework. It is open-source and released under the same GNU General Public License (GPL) as OpenFOAM. The source code is released as a publicly open software repository that includes detailed documentation and tutorial cases. Since mdFoam+ is designed entirely within the OpenFOAM C++ object-oriented framework, it inherits a number of key features. The code is designed for extensibility and flexibility, so it is aimed first and foremost as an MD research tool, in which new models and test cases can be developed and tested rapidly. Implementing mdFoam+ in OpenFOAM also enables easier development of hybrid methods that couple MD with continuum-based solvers. Setting up MD cases follows the standard OpenFOAM format, as mdFoam+ also relies upon the OpenFOAM dictionary-based directory structure. This ensures that useful pre- and post-processing capabilities provided by OpenFOAM remain available even though the fully Lagrangian nature of an MD simulation is not typical of most OpenFOAM applications. Results show that mdFoam+ compares well to another well-known MD code (e.g. LAMMPS) in terms of benchmark problems, although it also has additional functionality that does not exist in other open-source MD codes.

  7. Computation of Asteroid Proper Elements: Recent Advances

    Science.gov (United States)

    Knežević, Z.

    2017-12-01

    The recent advances in computation of asteroid proper elements are briefly reviewed. Although not representing real breakthroughs in computation and stability assessment of proper elements, these advances can still be considered as important improvements offering solutions to some practical problems encountered in the past. The problem of getting unrealistic values of perihelion frequency for very low eccentricity orbits is solved by computing frequencies using the frequency-modified Fourier transform. The synthetic resonant proper elements adjusted to a given secular resonance helped to prove the existence of Astraea asteroid family. The preliminary assessment of stability with time of proper elements computed by means of the analytical theory provides a good indication of their poorer performance with respect to their synthetic counterparts, and advocates in favor of ceasing their regular maintenance; the final decision should, however, be taken on the basis of more comprehensive and reliable direct estimate of their individual and sample average deviations from constancy.

  8. Computation of asteroid proper elements: Recent advances

    Directory of Open Access Journals (Sweden)

    Knežević Z.

    2017-01-01

    Full Text Available The recent advances in computation of asteroid proper elements are briefly reviewed. Although not representing real breakthroughs in computation and stability assessment of proper elements, these advances can still be considered as important improvements offering solutions to some practical problems encountered in the past. The problem of getting unrealistic values of perihelion frequency for very low eccentricity orbits is solved by computing frequencies using the frequencymodified Fourier transform. The synthetic resonant proper elements adjusted to a given secular resonance helped to prove the existence of Astraea asteroid family. The preliminary assessment of stability with time of proper elements computed by means of the analytical theory provides a good indication of their poorer performance with respect to their synthetic counterparts, and advocates in favor of ceasing their regular maintenance; the final decision should, however, be taken on the basis of more comprehensive and reliable direct estimate of their individual and sample average deviations from constancy.

  9. A Temporal and Spatial Analysis of Wave-Generated Foam Patterns in the Surf Zone

    Science.gov (United States)

    2017-01-10

    slides backward over the crest. Turner and Turner (2011) also discuss how foam is generated behind a spilling breaker. Their theory originates with the...with the two theories of foam hole generation. The fringe region is the most seaward foam region and is marked with circular foam rings that become...larger in area and more distinct with time. The fringe region data are contrary to observations of ODEs but is consistent with the theory of self

  10. Application of sustainable foaming agents to control the mobility of carbon dioxide in enhanced oil recovery

    Directory of Open Access Journals (Sweden)

    Roozbeh Rafati

    2012-12-01

    Full Text Available Carbon dioxide (CO2 flooding is a conventional process in which the CO2 is injected into the oil reservoir to increase the quantity of extracting oil. This process also controls the amount of released CO2 as a greenhouse gas in the atmosphere which is known as CO2 sequestration process. However, the mobility of the CO2 inside the hydrocarbon reservoir is higher than the crude oil and always viscous fingering and gravity override problems occur during a CO2 injection. The most common method to overcome these problems is to trap the gas bubbles in the liquid phase in the form of aqueous foam prior to CO2 injection. Although, the aqueous foams are not thermodynamically stable, special care should be considered to ensure bulk foam preparation and stability. Selection of a proper foaming agent from a large number of available surfactants is the main step in the bulk foam preparation. To meet this purpose, many chemical and crude oil based surfactants have been reported but most of them are not sustainable and have disposal problems. The objective of this experimental study is to employ Lignosulfonate and Alkyl Polyglucosides (APGs as two sustainable foaming agents for the bulk foam stability investigations and foam flooding performance in porous media. In the initial part, the bulk foam stability results showed that APGs provided more stable foams in comparison with Lignosulfonate in all surfactant concentrations. In the second part, the results indicated that the bulk foam stability measurements provide a good indication of foam mobility in porous media. The foaming agent’s concentration which provided the maximum foam stability also gave the highest value of mobility reduction in porous media.

  11. Active Debris Removal System Based on Polyurethane Foam

    Science.gov (United States)

    Rizzitelli, Federico; Valdatta, Marcelo; Bellini, Niccolo; Candini Gian, Paolo; Rastelli, Davide; Romei, Fedrico; Locarini, Alfredo; Spadanuda, Antonio; Bagassi, Sara

    2013-08-01

    Space debris is an increasing problem. The exponential increase of satellite launches in the last 50 years has determined the problem of space debris especially in LEO. The remains of past missions are dangerous for both operative satellites and human activity in space. But not only: it has been shown that uncontrolled impacts between space objects can lead to a potentially dangerous situation for civil people on Earth. It is possible to reach a situation of instability where the big amount of debris could cause a cascade of collisions, the so called Kessler syndrome, resulting in the infeasibility of new space missions for many generations. Currently new technologies for the mitigation of space debris are under study: for what concerning the removal of debris the use of laser to give a little impulse to the object and push it in a graveyard orbit or to be destroyed in the atmosphere. Another solution is the use of a satellite to rendezvous with the space junk and then use a net to capture it and destroy it in the reentry phase. In a parallel way the research is addressed to the study of deorbiting solutions to prevent the formation of new space junk. The project presented in this paper faces the problem of how to deorbit an existing debris, applying the studies about the use of polyurethane foam developed by Space Robotic Group of University of Bologna. The research is started with the Redemption experiment part of last ESA Rexus program. The foam is composed by two liquid components that, once properly mixed, trig an expansive reaction leading to an increase of volume whose entity depends on the chemical composition of the two starting components. It is possible to perform two kind of mission: 1) Not controlled removal: the two components are designed to react producing a low density, high expanded, spongy foam that incorporates the debris. The A/m ratio of the debris is increased and in this way also the ballistic parameter. As a consequence, the effect of

  12. Foam flow in a model porous medium: I. The effect of foam coarsening.

    Science.gov (United States)

    Jones, S A; Getrouw, N; Vincent-Bonnieu, S

    2018-02-02

    Foam structure evolves with time due to gas diffusion between bubbles (coarsening). In a bulk foam, coarsening behaviour is well defined, but there is less understanding of coarsening in confined geometries such as porous media. Previous predictions suggest that coarsening will cause foam lamellae to move to low energy configurations in the pore throats, resulting in greater capillary resistance when restarting flow. Foam coarsening experiments were conducted in both a model-porous-media micromodel and in a sandstone core. In both cases, foam was generated by coinjecting surfactant solution and nitrogen. Once steady state flow had been achieved, the injection was stopped and the system sealed off. In the micromodel, the foam coarsening was recorded using time-lapse photography. In the core flood, the additional driving pressure required to reinitiate flow after coarsening was measured. In the micromodel the bubbles coarsened rapidly to the pore size. At the completion of coarsening the lamellae were located in minimum energy configurations in the pore throats. The wall effect meant that the coarsening did not conform to the unconstricted growth laws. The coreflood tests also showed coarsening to be a rapid process. The additional driving pressure to restart flow reached a maximum after just 2 minutes.

  13. Physical Characteristics and Technology of Glass Foam from Waste Cathode Ray Tube Glass

    Directory of Open Access Journals (Sweden)

    G. Mucsi

    2013-01-01

    Full Text Available This paper deals with the laboratory investigation of cathode-ray-tube- (CRT- glass-based glass foam, the so-called “Geofil-Bubbles” which can be applied in many fields, mainly in the construction industry (lightweight concrete aggregate, thermal and sound insulation, etc.. In this study, the main process engineering material properties of raw materials, such as particle size distribution, moisture content, density, and specific surface area, are shown. Then, the preparation of raw cathode ray tube glass waste is presented including the following steps: crushing, grinding, mixing, heat curing, coating, and sintering. Experiments were carried out to optimize process circumstances. Effects of sintering conditions—such as temperature, residence time, and particle size fraction of green pellet—on the mechanical stability and particle density of glass foam particles were investigated. The mechanical stability (abrasion resistance was tested by abrasion test in a Deval drum. Furthermore, the cell structure was examined with optical microscopy and SEM. We found that it was possible to produce foam glass (with proper mechanical stability and particle density from CRT glass. The material characteristics of the final product strongly depend on the sintering conditions. Optimum conditions were determined: particle size fraction was found to be 4–6 mm, temperature 800°C, and residence time 7.5 min.

  14. Thermal Conductivity of Foam Glass

    DEFF Research Database (Denmark)

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

    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...... with different gas compositions. The foam glasses were characterised concerning densities, open/closed porosity and crystallinity. We find out, through analytical calculations and experiments, how the thermal conductivity of foam glass depends on density, glass composition and gas composition. Certain glass...

  15. Fabrication and Analysis of Microscale Aluminum Foam Precursor Particles by Use of Titanium Hydride

    Science.gov (United States)

    Key, Deanna E.

    The creation of aluminum foam precursor particles by use of a blowing agent, Titanium Hydride, is examined. The production of these precursor particles is highly dependent on the mechanical milling process, and the use of a process control agent (methanol) during milling. The effects of the process control agent allow for faster milling times, and the achievement of micro-scale particle sizes is achieved. In addition, the foaming characteristics of these particles are explored in depth, with the comparison of foaming environments, air vs. argon. The argon foaming environment was found to yield better foaming characteristics than that of air. This study is the first to create individual micro-scale aluminum foam precursor particles, as previous studies focused on that of bulk powder compacts. The successful creation of the micron scale aluminum foam precursor particles opens doors for the creation of hybrid foams.

  16. Applications of Foamed Lightweight Concrete

    Directory of Open Access Journals (Sweden)

    Mohd Sari Kamarul Aini

    2017-01-01

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

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

    OpenAIRE

    Peter W. Gaiser; Magdalena D. Anguelova

    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 ...

  18. Foaming in stout beers

    Science.gov (United States)

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

    2011-10-01

    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 several 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 fibers, 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 investigating the nucleation of gas bubbles. The equipment needed is modest, putting such experiments within reach of undergraduate laboratories. We also consider the suggestion that a widget could be constructed by coating the inside of a beer can with cellulose fibers.

  19. 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.

  20. Preparation and characterization of activated carbon foam from phenolic resin.

    Science.gov (United States)

    Zhao, Xuefei; Lai, Shiquan; Liu, Hongzha; Gao, Lijuan

    2009-01-01

    Activated carbon foam was successfully prepared from phenolic resin synthesized with phenol and formaldehyde under alkali condition. The influence of process variables, such as steam rate, carbonization temperature, carbonization time, activation temperature and activation time on the adsorption capacities of the activated carbon foam was studied. Under the optimum experimental conditions, the activated carbon foam with a specific surface area 727.62 m(2)/g was obtained. Moreover, the iodine value and carbon tetrachloride value of the activated carbon foam was 1050.28 mg/g and 401.37 mg/g, respectively. The pore size of the activated carbon foam was in the range of 3.5-5 nm which was determined through the N2 adsorption test. In addition, the yield of the activated carbon foam was 36.24%. The result of scanning electron microscopy (SEM) showed that the activated carbon foam became honeycomb structure, and its pore wall was thinner and smoother compared to the unactivated carbon foam.

  1. Headspace analysis of foams and fixatives

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-07-27

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

  2. Flow transitions in two-dimensional foams.

    Science.gov (United States)

    Gilbreth, Christopher; Sullivan, Scott; Dennin, Michael

    2006-11-01

    For sufficiently slow rates of strain, flowing foam can exhibit inhomogeneous flows. The nature of these flows is an area of active study in both two-dimensional model foams and three dimensional foam. Recent work in three-dimensional foam has identified three distinct regimes of flow [S. Rodts, J. C. Baudez, and P. Coussot, Europhys. Lett. 69, 636 (2005)]. Two of these regimes are identified with continuum behavior (full flow and shear banding), and the third regime is identified as a discrete regime exhibiting extreme localization. In this paper, the discrete regime is studied in more detail using a model two-dimensional foam: a bubble raft. We characterize the behavior of the bubble raft subjected to a constant rate of strain as a function of time, system size, and applied rate of strain. We observe localized flow that is consistent with the coexistence of a power-law fluid with rigid-body rotation. As a function of applied rate of strain, there is a transition from a continuum description of the flow to discrete flow when the thickness of the flow region is approximately ten bubbles. This occurs at an applied rotation rate of approximately 0.07 s-1.

  3. 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.

  4. Modeling Study: Mechanism of Foam Propagation in Porous Media at Different Levels of Minimum Mobilization Pressure Gradient

    Science.gov (United States)

    Izadi, M.; Kam, S.

    2017-12-01

    Scope: Numerous laboratory and field tests revealed that foam can effectively control gas mobility and improve sweep efficiency in enhanced-oil-recovery and subsurface-remediation processes, if correctly designed. The objective of this study is to answer (i) how mechanistic foam model parameters can be determined by fitting lab experiments in a step-by-step manner; (ii) how different levels of mobilization pressure gradient for foam generation affects the fundamentals of foam propagation; and (iii) how foam propagation distance can be estimated in the subsurface. This study for the first time shows why, and by how much, supercritical CO2 foams are advantaged over other types of foams such as N2 foam. Methods: First of all, by borrowing experimental data existing in the literature, this study shows how to capture mechanistic foam model parameters. The model, then, is applied to a wide range of mobilization pressure gradient to represent different types of foams that have been applied in the field (Note that supercritical CO2 foams exhibit much lower mobilization pressure compared to other types of foams (N2, steam, air, etc.). Finally, the model and parameters are used to evaluate different types of foam injection scenarios in order to predict how far foams can propagate with what properties in the field condition. Results and Conclusions: The results show that (i) the presence of three different foam states (strong, weak, intermediate) as well as two different strong-foam flow regimes (high-quality and low-quality regimes) plays a key role in model fit and field-scale propagation prediction and (ii) the importance of complex non-Newtonian foam rheology should not be underestimated. More specifically, this study finds that (i) supercritical CO2 foams can propagate a few hundreds of feet easily, which is a few orders of magnitude higher than other foams such as N2 foams; (ii) for dry foams (or, strong foams in the high-quality regime), the higher gas fractions the

  5. Fiber-reinforced syntactic foams

    Science.gov (United States)

    Huang, Yi-Jen

    Long fibers are generally preferred for reinforcing foams for performance reasons. However, uniform dispersion is difficult to achieve because they must be mixed with liquid resin prior to foam expansion. New approaches aiming to overcome such problem have been developed at USC's Composites Center. Fiber-reinforced syntactic foams with long fibers (over 6 mm in length) manufactured at USC's Composites Center have achieved promising mechanical properties and demonstrated lower density relative to conventional composite foams. Fiber-reinforced syntactic foams were synthesized from thermosetting polymeric microspheres (amino and phenolic microspheres), as well as thermoplastic PVC heat expandable microspheres (HEMs). Carbon and/or aramid fibers were used to reinforce the syntactic foams. Basic mechanical properties, including shear, tensile, and compression, were measured in syntactic foams and fiber-reinforced syntactic foams. Microstructure and crack propagation behavior were investigated by scanning electron microscope and light microscopy. Failure mechanisms and reinforcing mechanisms of fiber-reinforced syntactic foams were also analyzed. As expected, additions of fiber reinforcements to foams enhanced both tensile and shear properties. However, only limited enhancement in compression properties was observed, and fiber reinforcement was of limited benefit in this regard. Therefore, a hybrid foam design was explored and evaluated in an attempt to enhance compression properties. HEMs were blended with glass microspheres to produce hybrid foams, and hybrid foams were subsequently reinforced with continuous aramid fibers to produce fiber-reinforced hybrid foams. Mechanical properties of these foams were evaluated. Findings indicated that the production of hybrid foams was an effective way to enhance the compressive properties of syntactic foams, while the addition of fiber reinforcements enhanced the shear and tensile performance of syntactic foams. Another approach

  6. 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.

  7. Auxetic polyurethane foam: Manufacturing and processing analysis

    Science.gov (United States)

    Jahan, Md Deloyer

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

  8. Carbonate-Foaming Agents in Aluminum Foams: Advantages and Perspectives

    Science.gov (United States)

    Soloki, Ali; Esmailian, Mohammad

    2015-04-01

    Aluminum foams are commonly produced using hydride foaming agents. Carbonates are inexpensive and more convenient to handle than hydrides. In this review article, the replacement of titanium hydride by carbonate foaming agents in aluminum and aluminum alloys was studied. Carbonate-foaming agents including calcium carbonate, magnesium carbonate, and dolomite were investigated for the production of aluminum and aluminum alloys. The thermal decomposition behavior of the foaming agents was evaluated in conjunction with the cell structure of the aluminum foams produced. From the results, magnesium carbonate and dolomite were selected as suitable foaming agents for aluminum alloys because of lower decomposition temperature than calcium carbonate. It was clarified that dolomite resulted in a fine and homogenous cell structures.

  9. Production of lightweight foam glass (invited talk)

    DEFF Research Database (Denmark)

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

    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......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...... 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...

  10. Outgassing From Open And Closed Magma Foams

    Science.gov (United States)

    von Aulock, Felix W.; Kennedy, Ben M.; Maksimenko, Anton; Wadsworth, Fabian B.; Lavallée, Yan

    2017-06-01

    During magma ascent, bubbles nucleate, grow, coalesce, and form a variably permeable porous network. The volcanic system opens and closes as bubble walls reorganize, seal or fail. In this contribution we cause obsidian to nucleate and grow bubbles to high gas volume fraction at atmospheric pressure by heating samples to 950 ºC for different times and we image the growth through a furnace. Following the experiment, we imaged the internal pore structure of selected samples in 3D and then dissected for analysis of textures and dissolved water content remnant in the glass. We demonstrate that in these high viscosity systems, during foaming and subsequent foam-maturation, bubbles near a free surface resorb via diffusion to produce an impermeable skin of melt around a foam. The skin thickens nonlinearly through time. The water concentrations at the outer and inner skin margins reflect the solubility of water in the melt at the partial pressure of water in atmospheric and water-rich bubble conditions, respectively. In this regime, mass transfer of water out of the system is diffusion limited and the sample shrinks slowly. In a second set of experiments in which we polished off the skin of the foamed samples and placed them back in the furnace, we observe rapid sample contraction and collapse of the connected pore network under surface tension as the system efficiently outgasses. In this regime, mass transfer of water is permeability limited. The mechanisms described here are relevant to the evolution of pore network heterogeneity in permeable magmas. We conclude that diffusion-driven skin formation can efficiently seal connectivity in foams. When rupture of melt film around gas bubbles (i.e. skin removal) occurs, then rapid outgassing and consequent foam collapse modulate gas pressurisation in the vesiculated magma.

  11. Outgassing from Open and Closed Magma Foams

    Directory of Open Access Journals (Sweden)

    Felix W. von Aulock

    2017-06-01

    Full Text Available During magma ascent, bubbles nucleate, grow, coalesce, and form a variably permeable porous network. The reorganization, failing and sealing of bubble walls may contribute to the opening and closing of the volcanic system. In this contribution we cause obsidian to nucleate and grow bubbles to high gas volume fraction at atmospheric pressure by heating samples to 950°C for different times and we image the growth through a furnace. Following the experiment, we imaged the internal pore structure of selected samples in 3D and then dissected for analysis of textures and dissolved water content remnant in the glass. We demonstrate that in these high viscosity systems, during foaming and subsequent foam-maturation, bubbles near a free surface resorb via diffusion to produce an impermeable skin of melt around a foam. The skin thickens non-linearly through time. The water concentrations at the outer and inner skin margins reflect the solubility of water in the melt at the partial pressure of water in atmospheric and water-rich bubble conditions, respectively. In this regime, mass transfer of water out of the system is diffusion limited and the sample shrinks slowly. In a second set of experiments in which we polished off the skin of the foamed samples and placed them back in the furnace to allow open system outgassing, we observe rapid sample contraction and collapse of the connected pore network under surface tension as the system efficiently outgasses. In this regime, mass transfer of water is permeability limited. We conclude that diffusion-driven skin formation can efficiently seal connectivity in foams. When rupture of melt film around gas bubbles (i.e., skin removal occurs, then rapid outgassing and consequent foam collapse modulate gas pressurization in the vesiculated magma. The mechanisms described here are relevant to the evolution of pore network heterogeneity in permeable magmas.

  12. Virtual Treatment of Basilar Aneurysms Using Shape Memory Polymer Foam

    Science.gov (United States)

    Ortega, J.M.; Hartman, J.; Rodriguez, J.N.; Maitland, D.J.

    2013-01-01

    Numerical simulations are performed on patient-specific basilar aneurysms that are treated with shape memory polymer (SMP) foam. In order to assess the post-treatment hemodynamics, two modeling approaches are employed. In the first, the foam geometry is obtained from a micro-CT scan and the pulsatile blood flow within the foam is simulated for both Newtonian and non-Newtonian viscosity models. In the second, the foam is represented as a porous media continuum, which has permeability properties that are determined by computing the pressure gradient through the foam geometry over a range of flow speeds comparable to those of in vivo conditions. Virtual angiography and additional post-processing demonstrate that the SMP foam significantly reduces the blood flow speed within the treated aneurysms, while eliminating the high-frequency velocity fluctuations that are present within the pre-treatment aneurysms. An estimation of the initial locations of thrombus formation throughout the SMP foam is obtained by means of a low fidelity thrombosis model that is based upon the residence time and shear rate of blood. The Newtonian viscosity model and the porous media model capture similar qualitative trends, though both yield a smaller volume of thrombus within the SMP foam. PMID:23329002

  13. Asteroid proper elements and secular resonances

    Science.gov (United States)

    Knezevic, Zoran; Milani, Andrea

    1992-01-01

    In a series of papers (e.g., Knezevic, 1991; Milani and Knezevic, 1990; 1991) we reported on the progress we were making in computing asteroid proper elements, both as regards their accuracy and long-term stability. Additionally, we reported on the efficiency and 'intelligence' of our software. At the same time, we studied the associated problems of resonance effects, and we introduced the new class of 'nonlinear' secular resonances; we determined the locations of these secular resonances in proper-element phase space and analyzed their impact on the asteroid family classification. Here we would like to summarize the current status of our work and possible further developments.

  14. 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....... 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...... study was to identify potential causes of foaming in manure based digesters. Moreover, it was also an aim to investigate possible solutions to counteract foam formation with the use of antifoam agents. Thus, the impact of organic loading rate and content of feeding substrate on anaerobic digestion...

  15. Synchrotron tomography on metallic foams

    International Nuclear Information System (INIS)

    Haibel, A.; Banhart, J.

    2003-01-01

    Metallic foams are a class of materials with unique properties. In contrast to most aqueous foams which are stable due to surface active agents, the liquid state of metallic foams can be stabilized by admixing small non-soluble particles. We present the results of our investigations on such materials consisting three different components: an aluminium alloy, silicon carbide particles for foam stabilization, and titanium hydride acting as blowing agent. By means of synchrotron-tomography we visualized the three dimensional distribution of the silicon carbide and the titanium hydride particles in the unfoamed cast solid precursor, in the fully foamed liquid state, and in the solidified final state of the foam. We analyzed the silicon carbide formation in these three foaming stages and its influence of the pore stability

  16. Investigation the foam dynamics capacity of SDS in foam generator by affecting the presence of organic and inorganic contaminant

    Science.gov (United States)

    Haryanto, Bode; Siswarni, M. Z.; Sianipar, Yosef C. H.; Sinaga, Tongam M. A.; Bestari, Imam

    2017-05-01

    The effect of negative charge SDS monomer on its foam capacity with the presence of contaminants was investigated in foam generator. Generally, surfactant with higher concentration has higher foam capacity. The higher concentration will increase the number of monomer then increase the micelles in liquid phase. Increasing the number of monomer with the negative charge is a potential to increase interaction with metal ion with positive charge in solution. The presence of inorganic compound as metal ion with positive charge and organic compound (colloid) as particle of coffee impacting to generate the foam lamella with monomer is evaluated. Foam dynamic capacity of only SDS with variation of CMC, 1 x; 2 x; 3 x have the height 7.5, 8.0 and 8.3 cm respectively with the different range time were investigated. The Height of foam dynamic capacity with the presence of 20 ppm Cd2+ ion contaminant was 8.0, 8.3 and 8.4 cm at the same CMC variation of SDS. The presence of metal ion contaminant within the foam was confirmed by AAS. The black coffee particles and oil as contaminant decreased the foam capacity significantly in comparing to metal ions.

  17. Kosambi and Proper Orthogonal Decomposition

    Indian Academy of Sciences (India)

    In 1943 Kosambi published a paper titled 'Statis- tics in function space' in the Journal of the Indian. Mathematical Society. This paper was the first to propose the technique of statistical analysis of- ten called proper orthogonal decomposition to- day. This article describes the contents of that paper and Kosambi's approach to ...

  18. Foam, Foam-resin composite and method of making a foam-resin composite

    Science.gov (United States)

    Cranston, John A. (Inventor); MacArthur, Doug E. (Inventor)

    1995-01-01

    This invention relates to a foam, a foam-resin composite and a method of making foam-resin composites. The foam set forth in this invention comprises a urethane modified polyisocyanurate derived from an aromatic amino polyol and a polyether polyol. In addition to the polyisocyanurate foam, the composite of this invention further contains a resin layer, wherein the resin may be epoxy, bismaleimide, or phenolic resin. Such resins generally require cure or post-cure temperatures of at least 350.degree. F.

  19. Real-Time Cosmology with Gaia: Developing the Theory to Use Extragalactic Proper Motions to Make Dynamical Cosmological Tests, to Measure Geometric Distances, and to Detect Primordial Gravitational Waves

    Science.gov (United States)

    Darling, Jeremy

    A new field of study, "real-time cosmology," is now possible. This involves observing a dynamic universe that can be seen to change over human timescales. Most cosmological observations are geometrical, using standard candles or rulers to measure the expansion history and curvature as light propagates through the universe. Real-time cosmological measurements are dynamical, revealing the changing geometry of the universe - thus often providing geometrical distances independent of the canonical cosmological distance ladder - and are typically orthogonal to customary cosmological tests. This field of inquiry is no longer far-fetched, and this proposal demonstrates using extant data that many types of measurement are now within a factor of a few of being detectable, but the theory will very soon lag the observational capabilities. The Gaia mission will provide astrometry and proper motions of roughly 100 microarcseconds per year for half a million quasars by the end of its 5-year mission, but the theory for how to employ these data for cosmological tests has not been established. This project will develop the theory, models, and methods needed to make optimal use of the Gaia extragalactic proper motion measurements and to make significant new cosmological tests, distance measurements, and mass measurements. Gaia data can provide rich cosmological tests that are nearly model-independent. This work will build the theoretical framework enabling Gaia to measure or constrain: (1) The real-time growth and recession of structures, providing mass and distance measurements, (2) Extragalactic parallax for a statistical sample and individual galaxies, thus providing geometric distances, (3) The primordial stochastic long-period gravitational wave background, which deflects quasar light in a quadrupolar proper motion pattern, and (4) Cosmic shear, rotation, bulk motion, and local voids that may manifest as an apparent acceleration attributed to dark energy. One can also test the

  20. Transport of CO2 foam stabilized with engineered nanoparticles

    Science.gov (United States)

    Prigiobbe, V.; Worthen, A. J.; Aroonsri, A.; Huh, C.; Bryant, S. L.

    2014-12-01

    Foam injection into the subsurface is performed to improve gas control mobility for residual oil extraction in, e.g., enhanced oil recovery and contaminated site remediation. Foam improves the gas mobility control as the gas viscosity is increased through its dispersion into a liquid phase. Finer the bubbles the lower the gas apparent viscosity (or foam viscosity) and the better is the sweep efficiency of the residual oil. A chemical surfactant adsorbed at the gas-liquid interface is generally used to maintain an optimal foam texture (number of bubbles for unit volume) however it can be desorbed making the foam coarser. Here, we present an experimental and modeling study on the effect of nanoparticles on foam stability. Nanoparticles are adsorbed onto the bubble interface irreversibly and therefore they are expected to keep the desired texture of the foam for the entire time of its application. In this study, we use silica nanoparticles in conjunction with a surfactant to study the transport behavior of a CO2 foam in a porous medium. Experiments were performed using a glass-bead pack and Boise sandstone with foam quality (fg) 0.1-0.9 until steady-state. Foam flow was described by a mechanistic population balance model coupled with the fractional flow equation and constitutive equations for foam generation and destruction based on lamella division and bubble coalescence mechanisms, respectively. In order to minimize the uncertainty, model parameters were estimated by combining experimental data of pressure gradient during steady-state and transient. Experiments and theory agree very well and the overall results show a significant increase in foam texture and stability when nanoparticles and surfactant are added to a foam flow in a low permeability porous medium. Data from tests with various nanoparticle concentrations (cn) show that gas apparent viscosity changes with fg and cn. But its optimal value does not vary with cn and it is already attained at fg equal to 0

  1. Hydrogen combustion in aqueous foams

    International Nuclear Information System (INIS)

    Baer, M.R.; Griffiths, S.K.; Shepherd, J.E.

    1982-01-01

    Water fogs are recognized as an effective means to mitigate the effects of large-scale hydrogen combustion that might accompany some reactor loss-of-coolant reactor accidents. Fogs of sufficiently high density to produce large beneficial effects may, however, be difficult to generate and maintain. An alternate method of suspending the desired mass of water is via high expansion-ratio aqueous foams. Because the foam would be generated using the combustible gaseous contents of the containment vessel, combustion occurs inside the foam cells. Although foams generated with inert gas have been well studied for use in fire fighting, little is known about combustion in foams generated with flammable mixtures. To help assess the usefulness of aqueous foams in a mitigation plan, the authors have conducted open tube tests and closed vessel tests of hydrogen/air combustion with and without foam. At low and intermediate hydrogen concentrations, the foam has little effect on the ultimate isochoric pressure rise. Above 15% hydrogen concentration, the foam causes a significant reduction in the pressure rise. The maximum effect occurs at about 28% hydrogen where the peak overpressure is reduced by two and one-half. Despite this overall pressure reduction, the flame speed is increased by up to an order of magnitude for combustion in the foam and strong pressure fluctuations are observed near a hydrogen concentration of 23%

  2. Hydrogen combustion in aqueous foams

    International Nuclear Information System (INIS)

    Baer, M.R.; Griffiths, S.K.; Shepherd, J.E.

    1984-01-01

    Water fogs are recognized as an effective means to mitigate the effects of large-scale hydrogen combustion that might accompany some loss of coolant nuclear reactor accidents. Fogs of sufficiently high density to produce large beneficial effects may, however, be difficult to generate and maintain. An alternate method of suspending the desired mass of water is via high expansion-ratio aqueous foams. Because, in practice, the foam would be generated using the combustible gaseous contents of the containment vessel, combustion occurs inside the foam cells. Although foams generated with inert gas have been well studied for use in fire fighting, little is known about combustion in foams generated with flammable mixtures. To help assess the usefulness of aqueous foams in a mitigation plan, several open-tube tests and more than 100 closed-vessel tests of hydrogen/air combustion, with and without foam were conducted. At low and intermediate hydrogen concentrations, the foam has little effect on the ultimate isochoric pressure rise. Above 15% hydrogen concentration, the foam causes a significant reduction in the pressure rise. The maximum effect occurs at about 28% hydrogen (the stoichiometric limit is 29.6% hydrogen) where the peak overpressure is reduced by 2 1/2. Despite this overall pressure reduction, the flame speed is increased by up to an order of magnitude for combustion in the foam, and strong pressure fluctuations are observed near a hydrogen concentration of 23%

  3. Hydrogen combustion in aqueous foams

    International Nuclear Information System (INIS)

    Baer, M.; Griffiths, S.; Shepherd, J.

    1983-01-01

    Water fogs are recognized as an effective means to mitigate the effects of large-scale hydrogen combustion that might accompany some loss-of-coolant nuclear reactor accidents. Fogs of sufficiently high density to produce large beneficial effects may, however, be difficult to generate and maintain. An alternate method of suspending the desired mass of water is via high expansion-ratio aqueous foams. Because, in practice, the foam would be generated using the combustible gaseous contents of the containment vessel, combustion occurs inside the foam cells. Although foams generated with inert gas have been well studied for use in fire fighting, little is known about combustion in foams generated with flammable mixtures. To help assess the usefulness of aqueous foams in a mitigation plan, we have conducted several open tube tests and over one hundred closed vessel tests of hydrogen/air combustion with and without foam. At low and intermediate hydrogen concentrations, the foam has little effect on the ultimate isochoric pressure rise. Above 15% hydrogen concentration, the foam causes a significant reduction in the pressure rise. The maximum effect occurs at about 28% hydrogen (the stoichiometric limit is 29.6% hydrogen) where the peak overpressure is reduced by a factor of two and one-half. Despite this overall pressure reduction, the flame speed is increase by up to an order of magnitude for combustion in the foam and strong pressure fluctuations are observed near a hydrogen concentration of 23%

  4. Experimental Characterization of Innovative Viscoelastic Foams

    Directory of Open Access Journals (Sweden)

    Massimo Viscardi

    2016-05-01

    Full Text Available The evolutionary trend in the automotive industry has produced over time numerous performance and aesthetic innovations, however, the exponential development related to transportation technologies also introduced new requirements concerning the environmental impact [1]. The awareness of ecological issues has led to a reorganization of the evaluations and the vehicle design, currently aimed at reducing the problems that have emerged in empirical investigations and the parallel increase in environmental solutions. The vehicle renewal process involves targeted technical mutations both to observance of ecology as to the safety and comfort of the driver. New recyclable materials and more resistant have been developed in order to minimize the environmental impact of the vehicle even at the end of the operating life of its components, as well as solutions relating to the reduction of noise pollution generated as a response to the requirements of comfort. Modern research programs on a global scale have set themselves the objective of exploiting the potentiality of innovative technologies in the optimization of vehicles efficiency, the noise reduction and in the consequent reduction of fuel burn. One of the crucial topics in the greening of the new generation automotive sector is therefore the use and development of high vibro-acoustic performance materials. The goal of this research is properly focused on the analysis of viscoelastic materials appointed to increase the damping of the vibrations generated in a vehicle. The use of a viscoelastic material in this context is due to its high property to convert vibrational energy into heat, providing a significant dissipation of the vibrations. Trade-off analyses are performed in order define the stiffness and damping capacity of several viscoelastic foams with different thickness and density.

  5. Sclerosant foam structure and stability is strongly influenced by liquid air fraction.

    Science.gov (United States)

    Cameron, E; Chen, T; Connor, D E; Behnia, M; Parsi, K

    2013-10-01

    To determine the effects of sclerosant foam preparation and composition on foam structure, the time course of liquid drainage, and foam coarsening. Sodium tetradecyl sulphate (STS) and polidocanol (POL) foams were investigated in a range of concentrations (0.5-3%) and liquid-plus-air fractions (LAF; 1 + 2 to 1 + 8). Foam was injected into a vein simulation model (polyvinyl chloride tubing, inner diameter 3 mm, constant pressure 5-7 mmHg) filled with saline or blood. Liquid drainage, bubble count, and diameter were measured and documented by serial photography. Liquid drainage was faster in the vertical position than the horizontal one. In all variations, very small bubbles (diameter foams (foams (>250 μm) and by 7.5 minutes macro-foams (>500 μm) were formed. Following injection, the upper regions of foam coarsened faster as liquid drained to the bottom of the vessel. Wet preparations produced significantly smaller bubbles. Low concentration POL foam produced significantly higher bubble counts and coarsened slower than STS. Foam structure is strongly influenced by the LAF. Despite the initial formation of micro-bubbles in the syringe, mini- and macro-bubbles are formed in target vessels with time post-injection. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  6. Spectroscopic diagnosis of foam z-pinch plasmas on SATURN

    International Nuclear Information System (INIS)

    Nash, T.J.; Derzon, M.S.; Allshouse, G.; Deeney, C.; Jobe, D.; McGurn, J.; MacFarlane, J.J.; Wang, P.

    1996-01-01

    Solid and annular silicon aerogel and agar foams were shot on the accelerator SATURN to study plasma initiation, acceleration, and stagnation. SATURN delivers 7 MA with a 50 nsec rise time to these foam loads. We fielded several spectroscopic diagnostics to measure plasma parameters throughout the z-pinch discharge. A spatially resolved single frame time-gated EUV spectrometer measured the extent of plasma ablation off the surface foam. A time integrated crystal spectrometer showed that characteristic K shell radiation of silicon in the aerogel and of S and Na impurities in the agar were all attenuated when the foam loads were coated with a conductive layer of gold. The time resolved pinhole camera showed that in general the quality of the pinch implosions was poor but improved with increasing efforts to improve current continuity such as prepulse and conductive coatings

  7. Hemoproteins-nickel foam hybrids as effective supercapacitors.

    Science.gov (United States)

    Khairy, Mohamed; El-Safty, Sherif A

    2014-02-09

    The immobilization of hemeproteins onto a nickel foam electrode was developed for the first time, and the electrode exhibits remarkable electrochemical performance with higher capacitance and stability compared to synthetic pseudocapacitors.

  8. Discourse of the form and concentration of surfactants to ensure the sustainability foam-emulsive products

    Directory of Open Access Journals (Sweden)

    Oleg

    2015-05-01

    Full Text Available Introduction. Development of dry mixes for making spumy and emulsion products are topical, because nowadays there is a tendency to minimize the time spent on the process of cooking, which is achieved by the use of semi finished products high degree of readiness. Materials and methods. Foaming ability was determined by the method of multiplicity of the foam, the stability of unstable foam-by the half-life method of foam, highly resistant foam - as a ratio of the height of the column of foam after exposure for 24 hours. Results. Was determined the influence of sunflower oil on the foaming ability and half-life foam of systems «sodium caseinate-oil». It was found that getting systems with high index of foaming capacity and foam stability in the presence of oil in the system is impossible without the use of low molecular weight surfactants. Substantiated recommendations regarding the feasibility of using two surfactants in systems «sodium caseinate-surfactants-oil», which provide the necessary kinship surfaces air, fat and water phases. it has been found that the use of 2,5...3,5% mono-and diglycerides of fatty acid sand Lecithin’s 0.15...0.25% in the content of sodium caseinate about 0.5% allows to receive the stable foam-emulsive systems containing sunflower oil 7...8% and foaming ability about 640±1%. Conclusions. It is established that for ensuring high indicators foaming capacity and stability of foam-emulsive systems required the use of low-molecular surfactants. The research results, is recommended to use when developing technology of foam-emulsive products.

  9. Rheology of milk foams produced by steam injection.

    Science.gov (United States)

    Jimenez-Junca, Carlos A; Gumy, Jean C; Sher, Alexander; Niranjan, Keshavan

    2011-01-01

    Rheology of milk foams generated by steam injection was studied during the transient destabilization process using steady flow and dynamic oscillatory techniques: yield stress (τ(y) ) values were obtained from a stress ramp (0.2 to 25 Pa) and from strain amplitude sweep (0.001 to 3 at 1 Hz of frequency); elastic (G') and viscous (G″) moduli were measured by frequency sweep (0.1 to 10 Hz at 0.05 of strain); and the apparent viscosity (η(a) ) was obtained from the flow curves generated from the stress ramp. The effect of plate roughness and the sweep time on τ(y) was also assessed. Yield stress was found to increase with plate roughness whereas it decreased with the sweep time. The values of yield stress and moduli-G' and G″-increased during foam destabilization as a consequence of the changes in foam properties, especially the gas volume fraction, ϕ, and bubble size, R(32) (Sauter mean bubble radius). Thus, a relationship between τ(y) , ϕ, R(32) , and σ(surface tension) was established. The changes in the apparent viscosity, η, showed that the foams behaved like a shear thinning fluid beyond the yield point, fitting the modified Cross model with the relaxation time parameter (λ) also depending on the gas volume fraction. Overall, it was concluded that the viscoelastic behavior of the foam below the yield point and liquid-like behavior thereafter both vary during destabilization due to changes in the foam characteristics. Studying the transient rheology of milk foams during destabilization contributes to our knowledge of the relationships between the changes in foam properties: texture and mouth feel during the consumption of hot foamed beverages. © 2011 Institute of Food Technologists®

  10. Foam injection molding of thermoplastic elastomers: Blowing agents, foaming process and characterization of structural foams

    Science.gov (United States)

    Ries, S.; Spoerrer, A.; Altstaedt, V.

    2014-05-01

    Polymer foams play an important role caused by the steadily increasing demand to light weight design. In case of soft polymers, like thermoplastic elastomers (TPE), the haptic feeling of the surface is affected by the inner foam structure. Foam injection molding of TPEs leads to so called structural foam, consisting of two compact skin layers and a cellular core. The properties of soft structural foams like soft-touch, elastic and plastic behavior are affected by the resulting foam structure, e.g. thickness of the compact skins and the foam core or density. This inner structure can considerably be influenced by different processing parameters and the chosen blowing agent. This paper is focused on the selection and characterization of suitable blowing agents for foam injection molding of a TPE-blend. The aim was a high density reduction and a decent inner structure. Therefore DSC and TGA measurements were performed on different blowing agents to find out which one is appropriate for the used TPE. Moreover a new analyzing method for the description of processing characteristics by temperature dependent expansion measurements was developed. After choosing suitable blowing agents structural foams were molded with different types of blowing agents and combinations and with the breathing mold technology in order to get lower densities. The foam structure was analyzed to show the influence of the different blowing agents and combinations. Finally compression tests were performed to estimate the influence of the used blowing agent and the density reduction on the compression modulus.

  11. Benefits of polidocanol endovenous microfoam (Varithena®) compared with physician-compounded foams

    Science.gov (United States)

    Carugo, Dario; Ankrett, Dyan N; Zhao, Xuefeng; Zhang, Xunli; Hill, Martyn; O’Byrne, Vincent; Hoad, James; Arif, Mehreen; Wright, David DI

    2015-01-01

    Objective To compare foam bubble size and bubble size distribution, stability, and degradation rate of commercially available polidocanol endovenous microfoam (Varithena®) and physician-compounded foams using a number of laboratory tests. Methods Foam properties of polidocanol endovenous microfoam and physician-compounded foams were measured and compared using a glass-plate method and a Sympatec QICPIC image analysis method to measure bubble size and bubble size distribution, Turbiscan™ LAB for foam half time and drainage and a novel biomimetic vein model to measure foam stability. Physician-compounded foams composed of polidocanol and room air, CO2, or mixtures of oxygen and carbon dioxide (O2:CO2) were generated by different methods. Results Polidocanol endovenous microfoam was found to have a narrow bubble size distribution with no large (>500 µm) bubbles. Physician-compounded foams made with the Tessari method had broader bubble size distribution and large bubbles, which have an impact on foam stability. Polidocanol endovenous microfoam had a lower degradation rate than any physician-compounded foams, including foams made using room air (p foams. In all tests performed, CO2 foams were the least stable and different O2:CO2 mixtures had intermediate performance. In the biomimetic vein model, polidocanol endovenous microfoam had the slowest degradation rate and longest calculated dwell time, which represents the length of time the foam is in contact with the vein, almost twice that of physician-compounded foams using room air and eight times better than physician-compounded foams prepared using equivalent gas mixes. Conclusion Bubble size, bubble size distribution and stability of various sclerosing foam formulations show that polidocanol endovenous microfoam results in better overall performance compared with physician-compounded foams. Polidocanol endovenous microfoam offers better stability and cohesive properties in a biomimetic vein model compared to

  12. 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.

  13. 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.

  14. Spin Foam Models

    CERN Document Server

    Krasnov, K V

    1999-01-01

    The term ‘spin foam models’ was invented only a couple years ago by Baez to refer to a new approach to quantization of general relativity that appeared as an offsping of loop quantum gravity. Although this new approach was motivated, both logically and historically, by loop quantum gravity, it became clear by now that the two approaches are rather independent. While loop quantum gravity attempts to give a canonical quantization of general relativity, spin foam model approach is set to make sense of the path integral for gravity. Eventually, the two approaches will probably be shown to be equivalent, but no rigorous result to this effect exists as for now. In this thesis I develop the spin foam quantization of gravity from scratch, referring to results from loop quantum gravity only for comparison. I start from a review of 2 + 1 gravity and discuss different roots to quantize it. While some of them, as, for example, using Chern-Simons theory, only exist in 2 + 1, others can be generalized t...

  15. Production of Nigella sativa Beverage Powder under Foam Mat Drying Using Egg Albumen as a Foaming Agent

    Directory of Open Access Journals (Sweden)

    Norhazirah Affandi

    2017-01-01

    Full Text Available The aim of this study was to determine the feasibility of producing Nigella sativa powder under a foam mat drying technique. A central, composite design of experiments was used to optimize the drying condition and compare the solubility, the antioxidant and mineral content of roasted Nigella sativa, and the foam mat dried Nigella sativa powder. Foams were prepared from Nigella sativa solution by adding different concentrations of egg albumen (2.5%, 8.75%, and 15% w/w and methyl cellulose (0, 0.5% and 1% w/w, using whipping times of 2, 5, and 8 min. The drying temperature was set at 50–70 °C, with a foam thickness of 1, 2, and 3 mm. The optimum recorded conditions for the foaming process were 15% of egg albumen concentration, 0.69% of methyl cellulose concentration, and a whipping time of 8 min. Thus, the optimum conditions for the drying process were 60 °C, with 2 mm of foam thickness. The results showed that there were significant differences in DPPH inhibition, the total phenolic content, and mineral content, whereas no significant differences were recorded in the water solubility index between the roasted Nigella sativa and the foam mat dried Nigella sativa powder.

  16. Influence of Syringe Volume on Foam Stability in Sclerotherapy for Varicose Vein Treatment.

    Science.gov (United States)

    Bai, Taoping; Jiang, Wentao; Fan, Yubo

    2017-11-14

    Despite the popularity of sclerotherapy for treating varicose veins, it still exhibits various problems, such as pulmonary embolism, deep-vein thrombosis, phlebitis, and visual disorders. To investigate syringe volume influence on foam stability, obtain the foam decay rule, and provide a reference for clinics. Five types of syringes are used to prepare foam at room temperature with various liquid-gas ratios. Foam decay process experiments were performed 5 times and recorded by video. The stability indices used include drainage time, half-life, bubble diameter, bubble surface density, and drainage rate. The 30 and 2-mL syringes, respectively, recorded the highest and lowest drainage speeds. Foam drainage time and half-life, differences varied between 15 and 70 seconds, and 20 and 100 seconds, respectively. Foam bubble diameters were distributed over 0.1 to 2.0 mm with roughly 200 to 700 bubbles per square centimeter. Increased syringe volume causes the bubble diameter to increase. Thus, foam dispersion increases and foam half-life decreases; hence, foam becomes unstable. It is, thus, better to use a small syringe several times to prepare foam in clinics using segmented injections.

  17. Studies on Foam Decay Trend and Influence of Temperature Jump on Foam Stability in Sclerotherapy.

    Science.gov (United States)

    Bai, Taoping; Chen, Yu; Jiang, Wentao; Yan, Fei; Fan, Yubo

    2018-02-01

    This study investigated the influence of temperature jump and liquid-gas ratio on foam stability to derive the foam-decay law. The experimental group conditions were as follows: mutation temperatures (10°C, 16°C, 20°C, 23°C, 25°C, and 27°C to >37°C) and liquid-gas ratios (1:1, 1:2, 1:3, and 1:4). The control group conditions were as follows: temperatures (10°C, 16°C, 20°C, 23°C, 25°C and 27°C) and liquid-gas ratios (1:1, 1:2, 1:3, and 1:4). A homemade device manufactured using the Tessari DSS method was used to prepare the foam. The decay process was videotape recorded. In the drainage rate curve, the temperature rose, and the liquid-gas ratio varied from 1:1 to 1:4, causing faster decay. In the entire process, the foam volume decreased with increasing drainage rate. The relationships were almost linear. Comparison of the experimental and control groups shows that the temperature jump results in a drainage time range of 1 to 15 seconds. The half-life ranges from 10 to 30 seconds. The maximum rate is 18.85%. Changes in the preparation temperature yields a drainage time range of 3 to 30 seconds. The half-life varies from 20 to 60 seconds. Decreasing the temperature jump range and liquid-gas ratio gradually enhances the foam stability. The foam decay time and drainage rate exhibit an exponential function distribution.

  18. Steam foam studies in the presence of residual oil

    Energy Technology Data Exchange (ETDEWEB)

    Hutchinson, D.A.; Demiral, B.; Castanier, L.M.

    1992-05-01

    The lack of understanding regarding foam flow in porous media necessitates further research. This paper reports on going work at Stanford University aimed at increasing our understanding in the particular area of steam foams. The behavior of steam foam is investigated with a one dimensional (6 ft. {times} 2.15 in.) sandpack under residual oil conditions of approximately 12 percent. The strength of the in-situ generated foam, indicated by pressure drops, is significantly affected by injection procedure, slug size, and steam quality. The surfactant concentration effect is minor in the range studied. In the presence of residual oil the simultaneous injection of steam and surfactant fails to generate foam in the model even though the same procedure generates a strong foam in the absence of oil. Nevertheless when surfactant is injected as a slug ahead of the steam using a surfactant alternating (SAG) procedure, foam is generated. The suggested reason for the success of SAG is the increased phase mixing that results from steam continually having to reestablish a path through a slug of surfactant solution.

  19. High Temperature Epoxy Foam: Optimization of Process Parameters

    Directory of Open Access Journals (Sweden)

    Samira El Gazzani

    2016-06-01

    Full Text Available For many years, reduction of fuel consumption has been a major aim in terms of both costs and environmental concerns. One option is to reduce the weight of fuel consumers. For this purpose, the use of a lightweight material based on rigid foams is a relevant choice. This paper deals with a new high temperature epoxy expanded material as substitution of phenolic resin, classified as potentially mutagenic by European directive Reach. The optimization of thermoset foam depends on two major parameters, the reticulation process and the expansion of the foaming agent. Controlling these two phenomena can lead to a fully expanded and cured material. The rheological behavior of epoxy resin is studied and gel time is determined at various temperatures. The expansion of foaming agent is investigated by thermomechanical analysis. Results are correlated and compared with samples foamed in the same temperature conditions. The ideal foaming/gelation temperature is then determined. The second part of this research concerns the optimization of curing cycle of a high temperature trifunctional epoxy resin. A two-step curing cycle was defined by considering the influence of different curing schedules on the glass transition temperature of the material. The final foamed material has a glass transition temperature of 270 °C.

  20. Thermal assault and polyurethane foam-evaluating protective mechanisms

    International Nuclear Information System (INIS)

    Williamson, C.L.; Iams, Z.L.

    2004-01-01

    Rigid polyurethane foam utilizes a variety of mechanisms to mitigate the thermal assault of a ''regulatory burn''. Polymer specific heat and foam k-factor are of limited usefulness in predicting payload protection. Properly formulated rigid polyurethane foam provides additional safeguards by employing ablative mechanisms which are effective even when the foam has been crushed or fractured as a result of trauma. The dissociative transitions from polymer to gas and char, and the gas transport of heat from inside the package out into the environment are also thermal mitigators. Additionally, the in-situ production of an intumescent, insulative, carbonaceous char, confers thermal protection even when a package's outer steel skin has been breached. In this test program, 19 liter, ''Five gallon'' steel pails are exposed on one end to the flame of an ''Oil Burner'' as described in the US Federal Aviation Administration (FAA) ''Aircraft Materials Fire Test Handbook''. When burning 2 diesel at a nominal rate of 8.39 kg (18.5 pounds)/hr, the burner generates a high emissivity flame that impinges on the pail face with the thermal intensity of a full scale pool-fire environment. Results of these tests, TGA and MDSC analysis on the subject foams are reported, and their relevance to full size packages and pool fires are discussed

  1. Bi-liquid foams

    International Nuclear Information System (INIS)

    Sonneville, Odile

    1997-01-01

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

  2. 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.

  3. A novel biomimetic analysis system for quantitative characterisation of sclerosing foams used for the treatment of varicose veins.

    Science.gov (United States)

    Carugo, Dario; Ankrett, Dyan N; O'Byrne, Vincent; Willis, Sean; Wright, David D I; Lewis, Andrew L; Hill, Martyn; Zhang, Xunli

    2013-06-01

    A novel analysis system for the quantification of sclerosing foam properties under clinically relevant conditions was developed with the purpose of establishing a robust methodology for comparative characterisation of different foam formulations and production strategies. The developed biomimetic-inspired model comprised of 4 or 10 mm inner diameter polytetrafluoroethylene tubing, filled with a blood substitute and fixed to a platform with an adjustable inclination angle. Sclerosing foams were produced by mixing polidocanol with either atmospheric air or 100 % CO₂, using a double-syringe system method. Individual foams were injected into the tube, while videos were captured simultaneously. Videos were then transferred to an in-house computational foam analysis system (CFAS) which performed a sequence of semi-automated operations, allowing quantitative characterisation of sclerosing foam dynamic behaviour. Using CFAS, degradation rates of different foams were measured and the effect of gas composition, liquid sclerosant concentration and time delay between foam production and injection were evaluated.

  4. Interfacial Stabilization of Fiber-Laden Foams with Carboxymethylated Lignin toward Strong Nonwoven Networks.

    Science.gov (United States)

    Li, Shuai; Xiang, Wenchao; Järvinen, Marjo; Lappalainen, Timo; Salminen, Kristian; Rojas, Orlando J

    2016-08-03

    Wet foams were produced via agitation and compressed air bubbling of aqueous solutions of carboxymethylated lignin (CML). Bubble size and distribution were assessed in situ via optical microscopy. Foamability, bubble collapse rate, and foam stability (half-life time) were analyzed as a function of CML concentration, temperature, pH, and air content. Dynamic changes of the CML liquid foam were monitored by light transmission and backscattering. Cellulosic fibers of different aspect ratios (long pine fibers and short birch fibers) were suspended under agitation by the liquid foams (0.6% CML in the aqueous phase) with an air (bubble) content as high as 75% in volume. Remarkably, the half-life time of fiber-laden CML foams was 10-fold higher than that of the corresponding fiber-free liquid foam. Such lignin-based foams were demonstrated, after dewatering, as a precursor for the synthesis of nonwoven, layered structures. The resulting fiber networks (paper), obtained here for the first time with lignin-based foams, were characterized for pore size distribution, lignin retention, morphology, and physical-mechanical properties (network formation quality, density, air permeability, surface roughness, and tensile and internal bond strengths). The results were compared against structures obtained from foams stabilized with an anionic surfactant (SDS) as well as those from foam-free, water-based web-laying. Remarkably, compared to SDS, the foam-formed materials produced with CML displayed better bonding and tensile strengths. Overall, CML-based foams were found to be suitable carriers of cellulosic fibers and have opened the possibility for integrating fully biobased systems in foam-forming. This is an emerging option to increase the effective solids content in the system without compromising the quality of formed nonwoven materials while achieving reductions in water and energy consumption.

  5. An approach for characterising cellular polymeric foam structures using computed tomography

    Science.gov (United States)

    Chen, Youming; Das, Raj; Battley, Mark

    2018-02-01

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

  6. Foam rheology at large deformation

    Science.gov (United States)

    Géminard, J.-C.; Pastenes, J. C.; Melo, F.

    2018-04-01

    Large deformations are prone to cause irreversible changes in materials structure, generally leading to either material hardening or softening. Aqueous foam is a metastable disordered structure of densely packed gas bubbles. We report on the mechanical response of a foam layer subjected to quasistatic periodic shear at large amplitude. We observe that, upon increasing shear, the shear stress follows a universal curve that is nearly exponential and tends to an asymptotic stress value interpreted as the critical yield stress at which the foam structure is completely remodeled. Relevant trends of the foam mechanical response to cycling are mathematically reproduced through a simple law accounting for the amount of plastic deformation upon increasing stress. This view provides a natural interpretation to stress hardening in foams, demonstrating that plastic effects are present in this material even for minute deformation.

  7. Generation of ozone foam and its application for disinfection

    Science.gov (United States)

    Hiragaki, Keisuke; Ishimaru, Tomiya; Nakanishi, Masaru; Muraki, Ryouji; Nieda, Masanori; Yamabe, Chobei

    2015-07-01

    Generated ozone foam was applied to the disinfection of Pseudomonas fluorescens. The effect of disinfection has been confirmed experimentally and new equipment for the disinfection of hands using this ozone foam has been put on the market for the practical use. The ozone foam was produced in the foam generator after mixing the water including surfactant (30 mL/min) and air including ozone (1000 ppm = 2.14 g/m3 ~ 1600 ppm = 3.4 g/m3, 300 mL/min). The liquid-to-gas ratio is 100 L/m3. The concentration of dissolved ozone in the thin liquid films of the bubbles was about 3 mg/L which was measured by the chemical method of the KI absorption and titration of sodium thiosulfate solution. The disinfection test samples were prepared using the PET disk on which Pseudomonas fluorescens of its number of more than 108 were attached. Test sample was inserted into ozone foam set on the glass plate for one to 6 min. The survival rate log (N/N0 decreased with time and its value of about-2.6 (i.e., ~1/400) was obtained at 6 min (2 min × 3 times repeated). It was also confirmed that the ozone foam was useful for the disinfection of hands. For more effective disinfection (in case of taking a long time for foam melting), the ozone foam was broken by force and changed into ozone water by which the survival rate decreased ×4 (i.e., N/N0 = 1/10 000) at 4 ~ 6 min. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  8. Proper motion survey for solar nearby stars

    International Nuclear Information System (INIS)

    Goldman, Bertrand

    2001-01-01

    For its microlensing observations EROS 2 built one of the largest CCD mosaic opera ting since 1996. This instrument allowed us to survey a large area of the sky, to look for faint, cool compact objects in the Solar neighborhood that may contribute to the Dark Matter revealed by flat rotation curves of spiral galaxies and the Milky Way. We imaged over 400 square degrees, at least three times over four years, with a single, stable instrument. The aim of this work is the reduction, the analysis and the detection of high proper motion objects that would look like those expected in a dark halo. We selected and analyzed thousands of images taken in two bands, visible and near-infrared, and obtained a catalogue of several thousand stars with proper motion typically higher than 80 milli-arc-seconds per year. None of these candidates displays the expected properties of the halo objects: very high proper motion and faintness. The second part of our work was to put constraints on the contributions of white dwarfs and brown dwarfs ta the halo. To do that, we simulated our data set and estimated our sensitivity to halo objects. We compared our results about moderately high proper motion stars with existing Galactic models, and confirmed the robustness of these models. We deduced a upper limit ta the contribution of M v = 17.5 white dwarfs to the standard halo of 10% (at the 95% confidence level), or 5% of a 14 Gyr old halo, and to the contribution of brown dwarfs of 7% (95% C.L.). Finally, among our candidates, several interesting objects, that do not belong to the halo but are among the coolest and faintest known, have been discovered. Systematic search for faint, nearby objects thus lead us to study disk L dwarfs, as well as old white dwarfs of the disk. (author) [fr

  9. Fundamental Principles of Proper Space Kinematics

    Science.gov (United States)

    Wade, Sean

    It is desirable to understand the movement of both matter and energy in the universe based upon fundamental principles of space and time. Time dilation and length contraction are features of Special Relativity derived from the observed constancy of the speed of light. Quantum Mechanics asserts that motion in the universe is probabilistic and not deterministic. While the practicality of these dissimilar theories is well established through widespread application inconsistencies in their marriage persist, marring their utility, and preventing their full expression. After identifying an error in perspective the current theories are tested by modifying logical assumptions to eliminate paradoxical contradictions. Analysis of simultaneous frames of reference leads to a new formulation of space and time that predicts the motion of both kinds of particles. Proper Space is a real, three-dimensional space clocked by proper time that is undergoing a densification at the rate of c. Coordinate transformations to a familiar object space and a mathematical stationary space clarify the counterintuitive aspects of Special Relativity. These symmetries demonstrate that within the local universe stationary observers are a forbidden frame of reference; all is in motion. In lieu of Quantum Mechanics and Uncertainty the use of the imaginary number i is restricted for application to the labeling of mass as either material or immaterial. This material phase difference accounts for both the perceived constant velocity of light and its apparent statistical nature. The application of Proper Space Kinematics will advance more accurate representations of microscopic, oscopic, and cosmological processes and serve as a foundation for further study and reflection thereafter leading to greater insight.

  10. Advanced Signal Processing Techniques Applied to Terahertz Inspections on Aerospace Foams

    Science.gov (United States)

    Trinh, Long Buu

    2009-01-01

    The space shuttle's external fuel tank is thermally insulated by the closed cell foams. However, natural voids composed of air and trapped gas are found as by-products when the foams are cured. Detection of foam voids and foam de-bonding is a formidable task owing to the small index of refraction contrast between foam and air (1.04:1). In the presence of a denser binding matrix agent that bonds two different foam materials, time-differentiation of filtered terahertz signals can be employed to magnify information prior to the main substrate reflections. In the absence of a matrix binder, de-convolution of the filtered time differential terahertz signals is performed to reduce the masking effects of antenna ringing. The goal is simply to increase probability of void detection through image enhancement and to determine the depth of the void.

  11. 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.

  12. Infrared signal generation from AC induction field heating of graphite foam

    Energy Technology Data Exchange (ETDEWEB)

    Klett, James W.; Rios, Orlando

    2018-02-27

    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 to produce light. An energy conversion device utilizes light energy from the heated graphite foam to perform a light energy consuming function. A device for producing light and a method of converting energy are also disclosed.

  13. Fabrication of highly insulating foam glass made from CRT panel glass

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  14. Fabrication of Aluminum Tubes Filled with Aluminum Alloy Foam by Friction Welding

    Directory of Open Access Journals (Sweden)

    Yoshihiko Hangai

    2015-10-01

    Full Text Available Aluminum foam is usually used as the core of composite materials by combining it with dense materials, such as in Al foam core sandwich panels and Al-foam-filled tubes, owing to its low tensile and bending strengths. In this study, all-Al foam-filled tubes consisting of ADC12 Al-Si-Cu die-cast aluminum alloy foam and a dense A1050 commercially pure Al tube with metal bonding were fabricated by friction welding. First, it was found that the ADC12 precursor was firmly bonded throughout the inner wall of the A1050 tube without a gap between the precursor and the tube by friction welding. No deformation of the tube or foaming of the precursor was observed during the friction welding. Next, it was shown that by heat treatment of an ADC12-precursor-bonded A1050 tube, gases generated by the decomposition of the blowing agent expand the softened ADC12 to produce the ADC12 foam interior of the dense A1050 tube. A holding time during the foaming process of approximately tH = 8.5 min with a holding temperature of 948 K was found to be suitable for obtaining a sound ADC12-foam-filled A1050 tube with sufficient foaming, almost uniform pore structures over the entire specimen, and no deformation or reduction in the thickness of the tube.

  15. 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

  16. 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.

  17. Preparation of A356 Foam Aluminum by Means of Titanium Hydride

    Science.gov (United States)

    Sarajan, Zohair

    2017-09-01

    The effect of heating temperature and stirring time during preparation of foam aluminum alloy A356 on its relative porosity is studied. The optimum amount of the foam-forming agent, i.e., titanium hydride TiH2, facilitating uniform distribution of pores throughout the whole cross section of a hardened casting is determined. Optimum conditions are established for foam formation in a melt during stirring using a mixer are described.

  18. Analysis of Effective Interconnectivity of DegraPol-foams Designed for Negative Pressure Wound Therapy

    Directory of Open Access Journals (Sweden)

    Heike Hall

    2009-03-01

    Full Text Available Many wounds heal slowly and are difficult to manage. Therefore Negative Pressure Wound Therapy (NPWT was developed where polymer foams are applied and a defined negative pressure removes wound fluid, reduces bacterial burden and increases the formation of granulation tissue. Although NPWT is used successfully, its mechanisms are not well understood. In particular, different NPWT dressings were never compared. Here a poly-ester urethane Degrapol® (DP-foam was produced and compared with commercially available dressings (polyurethane-based and polyvinyl-alcohol-based in terms of apparent pore sizes, swelling and effective interconnectivity of foam pores. DP-foams contain relatively small interconnected pores; PU-foams showed large pore size and interconnectivity; whereas PVA-foams displayed heterogeneous and poorly interconnected pores. PVA-foams swelled by 40 %, whereas DP- and PU-foams remained almost without swelling. Effective interconnectivity was investigated by submitting fluorescent beads of 3, 20 and 45 mm diameter through the foams. DP- and PU-foams removed 70-90 % of all beads within 4 h, independent of the bead diameter or bead pre-adsorption with serum albumin. For PVA-foams albumin pre-adsorbed beads circulated longer, where 20 % of 3 mm and 10 % of 20 mm diameter beads circulated after 96 h. The studies indicate that efficient bead perfusion does not only depend on pore size and swelling capacity, but effective interconnectivity might also depend on chemical composition of the foam itself. In addition due to the efficient sieve-effect of the foams uptake of wound components in vivo might occur only for short time suggesting other mechanisms being decisive for success of NPWT.

  19. Proper alignment of the microscope.

    Science.gov (United States)

    Rottenfusser, Rudi

    2013-01-01

    The light microscope is merely the first element of an imaging system in a research facility. Such a system may include high-speed and/or high-resolution image acquisition capabilities, confocal technologies, and super-resolution methods of various types. Yet more than ever, the proverb "garbage in-garbage out" remains a fact. Image manipulations may be used to conceal a suboptimal microscope setup, but an artifact-free image can only be obtained when the microscope is optimally aligned, both mechanically and optically. Something else is often overlooked in the quest to get the best image out of the microscope: Proper sample preparation! The microscope optics can only do its job when its design criteria are matched to the specimen or vice versa. The specimen itself, the mounting medium, the cover slip, and the type of immersion medium (if applicable) are all part of the total optical makeup. To get the best results out of a microscope, understanding the functions of all of its variable components is important. Only then one knows how to optimize these components for the intended application. Different approaches might be chosen to discuss all of the microscope's components. We decided to follow the light path which starts with the light source and ends at the camera or the eyepieces. To add more transparency to this sequence, the section up to the microscope stage was called the "Illuminating Section", to be followed by the "Imaging Section" which starts with the microscope objective. After understanding the various components, we can start "working with the microscope." To get the best resolution and contrast from the microscope, the practice of "Koehler Illumination" should be understood and followed by every serious microscopist. Step-by-step instructions as well as illustrations of the beam path in an upright and inverted microscope are included in this chapter. A few practical considerations are listed in Section 3. Copyright © 2013 Elsevier Inc. All rights

  20. Injectable foams for regenerative medicine.

    Science.gov (United States)

    Prieto, Edna M; Page, Jonathan M; Harmata, Andrew J; Guelcher, Scott A

    2014-01-01

    The design of injectable biomaterials has attracted considerable attention in recent years. Many injectable biomaterials, such as hydrogels and calcium phosphate cements (CPCs), have nanoscale pores that limit the rate of cellular migration and proliferation. While introduction of macroporosity has been suggested to increase cellular infiltration and tissue healing, many conventional methods for generating macropores often require harsh processing conditions that preclude their use in injectable foams. In recent years, processes such as porogen leaching, gas foaming, and emulsion-templating have been adapted to generate macroporosity in injectable CPCs, hydrogels, and hydrophobic polymers. While some of the more mature injectable foam technologies have been evaluated in clinical trials, there are challenges remaining to be addressed, such as the biocompatibility and ultimate fate of the sacrificial phase used to generate pores within the foam after it sets in situ. Furthermore, while implantable scaffolds can be washed extensively to remove undesirable impurities, all of the components required to synthesize injectable foams must be injected into the defect. Thus, every compound in the foam must be biocompatible and noncytotoxic at the concentrations utilized. As future research addresses these critical challenges, injectable macroporous foams are anticipated to have an increasingly significant impact on improving patient outcomes for a number of clinical procedures. © 2013 Wiley Periodicals, Inc.

  1. Identifying the Imprint of Surfactant Stabilisation in Whitecap Foam Evolution

    Science.gov (United States)

    Callaghan, A. H.; Deane, G. B.; Stokes, D.

    2016-02-01

    Surfactants are ubiquitous in the world's oceans and can affect climatically-relevant processes such as air-sea gas exchange, sea spray aerosol (SSA) flux, and air-sea momentum transfer. Surfactants are amphiphilic and help form the physically and chemically distinct ocean surface microlayer (SML), however, the spatial distribution, concentration and composition of the SML is not well understood, especially under conditions of vigorous wave breaking. Like the SML, breaking waves also influence physical exchange processes at the air-sea interface, and oceanic whitecap foam coverage is commonly used to quantify bubble-mediated exchange processes. However, surfactants can increase the lifetime of foam over clean water conditions, potentially complicating the use of whitecap coverage to parameterise air-sea gas exchange and SSA production flux. A better understanding of how surfactants affect the evolution of whitecap foam is needed to improve whitecap parameterisations of bubble-mediated processes, and may also provide a remote sensing approach to map the spatial distribution of surfactants at the water surface. Here we present results from a laboratory study that looked at whitecap foam evolution in "clean" and "surfactant-added" seawater regimes. We find that the whitecap foam area growth timescale is largely insensitive to the presence of surfactants, but that surfactant stabilization of whitecap foam becomes important during the whitecap foam area decay phase. The timescale at which this occurs appears to be consistent for breaking waves of different scale and intensity. A simple method is then used to isolate the surfactant signal and derive an equivalent "clean" seawater foam decay time for the whitecaps in the "surfactant-added" regime. The method is applied to oceanic whitecaps and results compared to the laboratory whitecaps from the "clean" and "surfactant-added" regimes.

  2. Wall slip of bubbles in foams

    Science.gov (United States)

    Saugey, A.; Drenckhan, W.; Weaire, D.

    2006-05-01

    We present a computational analysis of the flow of liquid foam along a smooth wall, as encountered in the transport of foams in vessels and pipes. We concentrate on the slip of the bubbles at the wall and present some novel finite element calculations of this motion for the case of fully mobile gas/liquid interfaces. Our two-dimensional simulations provide for the first time the bubble shapes and entire flow field, giving detailed insight into the distribution of stresses and dissipation in the system. In particular, we investigate the relationship between the drag force and the slip velocity of the bubble, which for small slip velocities obeys power laws, as predicted by previous semianalytical treatments.

  3. Production of Polystyrene Open-celled Microcellular Foam in Batch Process by Super Critical CO2

    Directory of Open Access Journals (Sweden)

    M.S. Enayati

    2010-12-01

    Full Text Available Open-celled foams are capable to allow the passage of fluids through their structure, because of interconnections between the open cells or bubbles and therefore these structures can be used as a membrane and filter. In thiswork, we have studied the production of polystyrene open-celled microcellular foam by using CO2 as blowing agent. To achieve such structures, it is necessary to control the stages of growth in such a way that the cells would connect to each other through the pores without any coalescence. The required processing condition to achieve open-celled structures is predictable by a model theory of opened-cell. This model suggests that at least a 130 bar saturation pressure and foaming time between 9 and 58 s are required for this system. The temperature range has been selected for to be both higher than polymer glass transition temperature and facilitating the foaming process. Experimental results in the batch foaming process has verified the model quite well. The SEM and mercury porousimetry tests show the presence of pores between the cells with open-celled structure. Experimental results show that by increasing the saturation pressure and the foaming temperature, there is a drop in the time required for open-celled structure formation. A 130 bar saturation pressure, 150o C foaming temperature and 60 s foaming time, suggest the attainment of open-celled microcellular foam based on polystyrene/CO2 system in the batch process.

  4. Optimization of process parameters for foam-mat drying of papaya pulp.

    Science.gov (United States)

    Kandasamy, Palani; Varadharaju, N; Kalemullah, S; Maladhi, D

    2014-10-01

    Experiments were carried out to optimize the process parameters for production of papaya powder using foam-mat drying. Papaya pulp was foamed by incorporating methyl cellulose (0.25, 0.5, 0.75 and 1 %, w/w), glycerol-mono-stearate (1, 2, 3 and 4 %, w/w) and egg white (5, 10, 15 and 20 %, w/w) as foaming agents. The maximum stable foam formation was 72, 90 and 125% at 0.75 % methyl cellulose, 3 % glycerol-mono-stearate and 15 % egg white respectively with 9°Brix pulp and whipping time of 20 min. The foamed pulp was dried at air temperature of 60, 65 and 70 °C with foam thickness of 2, 4, 6, 8 and 10 mm in a batch type cabinet dryer. The drying time required for foamed papaya pulp was lower than non-foamed pulp at all selected temperatures. Biochemical analysis results showed a significant reduction in ascorbic acid, β-carotene and total sugars in the foamed papaya dried product at higher foam thickness (6, 8 and 10 mm) and temperature (65 and 70 °C due to destruction at higher drying temperature and increasing time. There was no significant change in other biochemical constituents such as pH and acidity. The organoleptic and sensory evaluation of the quality attributes of papaya powder obtained from the pulp of 9°Brix added with 3 % glycerol-mono-stearate, whipped for 20 min and dried with a foam thickness of 4 mm at a temperature of 60 °C was found to be optimum to produce the foam-mat dried papaya powder.

  5. A foam ablation model for lost foam casting of aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Barone, M.R.; Caulk, D.A. [General Motors Research and Development Center, Warren, MI (United States)

    2005-09-01

    A model is developed for heat transfer, polymer vaporization, and gas diffusion at the interface between the advancing liquid metal and the receding foam pattern during mold filling in lost foam casting of aluminum. Most of the pattern interior decomposes by ablation, but the boundary cells decompose by a collapse mechanism, which creates an undercut in the pattern next to the coating. By regulating how much of the pattern coating is exposed to gas diffusion, the undercut controls the overall filling speed of the metal through the mold. Computed values for the foam decomposition energy from this model compare very well with experimental data on foam pyrolysis, and predicted filling speeds are consistent with observations in published experiments. In addition, the model explains several unusual observations about mold filling that until now have not been understood. (author)

  6. A foam melting model for lost foam casting of aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Caulk, D.A. [Manufacturing Systems Research Laboratory, General Motors Research and Development Center, 30500 Mound Road, Warren, MI 48090-9055 (United States)

    2006-07-15

    In lost foam casting of aluminum the liquid metal normally decomposes the foam pattern by ablation. But sometimes polymer vapor bubbling through the liquid metal accumulates along an upward-facing flow front until it opens a finite gap between the liquid metal and the decomposing foam. This changes the foam decomposition mechanism along that front from direct ablation to melting. A mathematical model is formulated for heat conduction, convection, and radiation across the gap, coupled with the vaporization of the excess polymer liquid behind the metal front and the resulting buoyant movement of polymer vapor bubbles through the liquid metal. Both models are combined to obtain an analytical solution for one-dimensional bottom filling of a pattern with uniform thickness. The results from this solution not only compare well with available experimental data, but they also explain how part thickness, metal temperature, and pressure affect filling speeds in bottom-fill situations. (author)

  7. Study of the relationships between nuclear decontamination foams stability and their physicochemical properties

    International Nuclear Information System (INIS)

    Dame, C.

    2006-03-01

    The LPAD (French Atomic Energy Commission) develops innovative processes in the frame of the future dismantling of nuclear facilities. Formulations were developed using high viscosified foams stabilized by biodegradable nonionic surfactants: alkyl poly-glucosides and viscosifiers (xanthan gum), which allow us to increase the foam lifetime and thus contact time of chemical reactants with the facility walls. We have considered the relationships between physicochemical properties and foam stability through the exploration of the foam at three different scales: from the molecular range (micelles, surface tension and visco-elasticity), to the film and Plateau border range (XR reflectivity, surface shear viscosity) and to macroscopic range, meaning the whole foam (foaminess, liquid fraction and wall film thickness evolution). Finally, exploratory study is presented concerning simultaneous foam three scales characterisation by small angle neutron scattering. (author)

  8. Foam rheology: a model of viscous phenomena

    International Nuclear Information System (INIS)

    Kraynik, A.M.; Hansen, M.G.

    1987-01-01

    A theoretical model for foam rheology that includes viscous forces is developed by considering the deformation of two-dimensional, spatially periodic cells in simple shearing and planar extensional flow. The undeformed hexagonal cells are separated by thin liquid films. Plateau border curvature and liquid drainage between films is neglected. Interfacial tension and viscous tractions due to stretching lamellar liquid determine the individual film tensions. The network motion is described by a system of nonlinear ordinary differential equations for which numerical solutions are obtained. Coalescense and disproportionation of Plateau borders results in the relative separation of cells and provides a mechanism for yielding and flow. This process is assumed to occur when a film's length reduces to its thickness. The time and position dependence of the cell-scale dynamics are computed explicitly. The effective continuum stress of the foam is described by instantaneous and time-averaged quantities. The capillary number, a dimensionless deformation rate, represents the relative importance of viscous and surface tension effects. The small-capillary-number or quasistatic response determines a yield stress. The dependence of the shear and normal stress material functions upon deformation rate, foam structure and physical properties is determined. A plausible mechanism for shear-induced material failure, which would determine a shear strength, is revealed for large capillary numbers. The mechanism involves large cell distortion and film thinning, which provide favorable conditions for film rupture

  9. Composite carbon foam electrode

    Science.gov (United States)

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

    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.

  10. 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...

  11. 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.

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

    Science.gov (United States)

    Fang, Qi

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

  13. DIFFERENT PORE SIZE ALUMINA FOAMS AND STUDY OF THEIR MECHANICAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    A. Hadi

    2015-03-01

    Full Text Available Recently, the open-cell ceramic foams have been extensively investigated due to special properties of these structures. They are excellent candidates for various applications such as molten metal and hot gas filtration, fabrication of metal matrix composites (MMC, heat exchangers and catalyst support. In this study to prepare high strength and high permeable foams, alumina suspensions with proper solid contents and suitable rheological behavior were used for different pore density foams. The properties of the prepared foams such as mean pore size, total porosity, mechanical strength and water permeability were characterized by using different techniques. A reduction in pore density caused an increase in total porosity from 78.5 % to 83 %. The compression strength of the samples was dependent on total porosity as well as properties of the suspension. Compression strengths of 1.77; 3.24 and 3.55 MPa were measured for 10, 17 and 27 ppi foams, respectively. Presence of high volume of permeable pores and good uniformity of the structure led to high permeable foams. The permeability measurement confirmed a rise in permeability rate with a decrease in pore density of the foams.

  14. Towards proper name generation : A corpus analysis

    NARCIS (Netherlands)

    Castro Ferreira, Thiago; Wubben, Sander; Krahmer, Emiel

    We introduce a corpus for the study of proper name generation. The corpus consists of proper name references to people in webpages, extracted from the Wikilinks corpus. In our analyses, we aim to identify the different ways, in terms of length and form, in which a proper names are produced

  15. Foam shell project: Progress report

    International Nuclear Information System (INIS)

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

    1994-01-01

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

  16. Foam dressings for treating pressure ulcers.

    Science.gov (United States)

    Walker, Rachel M; Gillespie, Brigid M; Thalib, Lukman; Higgins, Niall S; Whitty, Jennifer A

    2017-10-12

    to various combinations of selection, performance, attrition, detection and reporting bias, and imprecision due to small sample sizes and wide confidence intervals. We had very little confidence in the estimate of effect of included studies. Where a foam dressing was compared with another foam dressing, we established that the true effect was likely to be substantially less than the study's estimated effect.We present data for four comparisons.One trial compared a silicone foam dressing with another (hydropolymer) foam dressing (38 participants), with an eight-week (short-term) follow-up. It was uncertain whether alternate types of foam dressing affected the incidence of healed pressure ulcers (RR 0.89, 95% CI 0.45 to 1.75) or adverse events (RR 0.37, 95% CI 0.04 to 3.25), as the certainty of evidence was very low, downgraded for serious limitations in study design and very serious imprecision.Four trials with a median sample size of 20 participants (230 participants), compared foam dressings with hydrocolloid dressings for eight weeks or less (short-term). It was uncertain whether foam dressings affected the probability of healing in comparison to hydrocolloid dressings over a short follow-up period in three trials (RR 0.85, 95% CI 0.54 to 1.34), very low-certainty evidence, downgraded for very serious study limitations and serious imprecision. It was uncertain if there was a difference in risk of adverse events between groups (RR 0.88, 95% CI 0.37 to 2.11), very low-certainty evidence, downgraded for serious study limitations and very serious imprecision. Reduction in ulcer size, patient satisfaction/acceptability, pain and cost effectiveness data were also reported but we assessed the evidence as being of very low certainty.One trial (34 participants), compared foam and hydrogel dressings over an eight-week (short-term) follow-up. It was uncertain if the foam dressing affected the probability of healing (RR 1.00, 95% CI 0.78 to 1.28), time to complete healing (MD

  17. Influência do tempo de indução nas propriedades de hidroxiapatita porosa obtida por gelcasting de espumas Influence of the induction time on the properties of porous hydroxyapatite obtained by gelcasting foams

    Directory of Open Access Journals (Sweden)

    T. M. Volkmer

    2007-12-01

    Full Text Available Hidroxiapatita é uma cerâmica bioativa que permite o crescimento de tecido ósseo e revascularização da área implantada pela formação de ligação com a fase mineral dos ossos. Este estudo teve como objetivo a obtenção de blocos porosos de hidroxiapatita através do método gelcasting de espuma, sem a utilização de atmosfera controlada para a realização das polimerizações. O processo gelcasting de espumas consiste na incorporação de uma fase gasosa dispersa dentro de uma suspensão cerâmica contendo o pó cerâmico, água, defloculantes, ligantes e agentes de gelificação. O sistema de gelificação consiste no monômero acrilamida e no co-monômero N,N’ metilenobisacrilamida difuncional (MBAM. Foi estudada a variação das quantidades de iniciador e de acelerador e verificou-se a variação do tempo de indução e seus reflexos nas propriedades da hidroxiapatita porosa. Avaliou-se a porosidade, a macroestrutura, a distribuição de tamanho de poros e a permeabilidade. Verificou-se que é possível controlar a porosidade variando-se o tempo de indução e a ausência de atmosfera controlada não impediu a obtenção das peças porosas.Hydroxyapatite (HA is a bioactive ceramic that allows bone growth and revascularization of the area of implantation trough the formation of chemical bonding with the mineral phase of the bones. The aim of this work was to obtain porous blocks of HA by the gelcasting foams method without atmosphere control. The gelcasting foams process consists in the incorporation of a dispersed gaseous phase, with the help of a surfactant, inside a ceramic suspension containing the ceramic powder, water and gelation agents. The gelation system is composed by one monomer, acrylamide, and one comonomer, methylenebisacrylamide (MBAM. The effect of the accelerator and initiator amounts on the induction time, porosity, pore size distribution and permeability was evaluated. It was possible to control the porosity

  18. Method and apparatus for producing a carbon based foam article having a desired thermal-conductivity gradient

    Science.gov (United States)

    Klett, James W [Knoxville, TN; Cameron, Christopher Stan [Sanford, NC

    2010-03-02

    A carbon based foam article is made by heating the surface of a carbon foam block to a temperature above its graphitizing temperature, which is the temperature sufficient to graphitize the carbon foam. In one embodiment, the surface is heated with infrared pulses until heat is transferred from the surface into the core of the foam article such that the graphitizing temperature penetrates into the core to a desired depth below the surface. The graphitizing temperature is maintained for a time sufficient to substantially entirely graphitize the portion of the foam article from the surface to the desired depth below the surface. Thus, the foam article is an integral monolithic material that has a desired conductivity gradient with a relatively high thermal conductivity in the portion of the core that was graphitized and a relatively low thermal conductivity in the remaining portion of the foam article.

  19. Blending Novatein¯ thermoplastic protein with PLA for carbon dioxide assisted batch foaming

    Science.gov (United States)

    Walallavita, Anuradha; Verbeek, Casparus J. R.; Lay, Mark

    2016-03-01

    The convenience of polymeric foams has led to their widespread utilisation in everyday life. However, disposal of synthetic petroleum-derived foams has had a detrimental effect on the environment which needs to be addressed. This study uses a clean and sustainable approach to investigate the foaming capability of a blend of two biodegradable polymers, polylactic acid (PLA) and Novatein® Thermoplastic Protein (NTP). PLA, derived from corn starch, can successfully be foamed using a batch technique developed by the Biopolymer Network Ltd. NTP is a patented formulation of bloodmeal and chemical additives which can be extruded and injection moulded similar to other thermoplastics. However, foaming NTP is a new area of study and its interaction with blowing agents in the batch process is entirely unknown. Subcritical and supercritical carbon dioxide have been examined individually in two uniquely designed pressure vessels to foam various compositions of NTP-PLA blends. Foamed material were characterised in terms of expansion ratio, cell size, and cellular morphology in order to study how the composition of NTP-PLA affects foaming with carbon dioxide. It was found that blends with 5 wt. % NTP foamed using subcritical CO2 expanded up to 11 times due to heterogeneous nucleation. Morphology analysis using scanning electron microscopy showed that foams blown with supercritical CO2 had a finer cell structure with consistent cell size, whereas, foams blown with subcritical CO2 ranged in cell size and showed cell wall rupture. Ultimately, this research would contribute to the production of a biodegradable foam material to be used in packaging applications, thereby adding to the application potential of NTP.

  20. 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

  1. Blending Novatein{sup ®} thermoplastic protein with PLA for carbon dioxide assisted batch foaming

    Energy Technology Data Exchange (ETDEWEB)

    Walallavita, Anuradha, E-mail: asw15@students.waikato.ac.nz; Verbeek, Casparus J. R., E-mail: jverbeek@waikato.ac.nz; Lay, Mark, E-mail: mclay@waikato.ac.nz [University of Waikato, Hamilton 3240 (New Zealand)

    2016-03-09

    The convenience of polymeric foams has led to their widespread utilisation in everyday life. However, disposal of synthetic petroleum-derived foams has had a detrimental effect on the environment which needs to be addressed. This study uses a clean and sustainable approach to investigate the foaming capability of a blend of two biodegradable polymers, polylactic acid (PLA) and Novatein® Thermoplastic Protein (NTP). PLA, derived from corn starch, can successfully be foamed using a batch technique developed by the Biopolymer Network Ltd. NTP is a patented formulation of bloodmeal and chemical additives which can be extruded and injection moulded similar to other thermoplastics. However, foaming NTP is a new area of study and its interaction with blowing agents in the batch process is entirely unknown. Subcritical and supercritical carbon dioxide have been examined individually in two uniquely designed pressure vessels to foam various compositions of NTP-PLA blends. Foamed material were characterised in terms of expansion ratio, cell size, and cellular morphology in order to study how the composition of NTP-PLA affects foaming with carbon dioxide. It was found that blends with 5 wt. % NTP foamed using subcritical CO{sub 2} expanded up to 11 times due to heterogeneous nucleation. Morphology analysis using scanning electron microscopy showed that foams blown with supercritical CO{sub 2} had a finer cell structure with consistent cell size, whereas, foams blown with subcritical CO{sub 2} ranged in cell size and showed cell wall rupture. Ultimately, this research would contribute to the production of a biodegradable foam material to be used in packaging applications, thereby adding to the application potential of NTP.

  2. Fast algorithms for finding proper strategies in game trees

    DEFF Research Database (Denmark)

    Miltersen, Peter Bro; Sørensen, Troels Bjerre

    2008-01-01

    We show how to find a normal form proper equilibrium in behavior strategies of a given two-player zero-sum extensive form game with imperfect information but perfect recall. Our algorithm solves a finite sequence of linear programs and runs in polynomial time. For the case of a perfect information...... game, we show how to find a normal form proper equilibrium in linear time by a simple backwards induction procedure....

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

    International Nuclear Information System (INIS)

    Kim, Nohyu; Yang, Seung Yong

    2016-01-01

    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

  4. 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.

  5. The Synergy of Double Cross-linking Agents on the Properties of Styrene Butadiene Rubber Foams

    Science.gov (United States)

    Shao, Liang; Ji, Zhan-You; Ma, Jian-Zhong; Xue, Chao-Hua; Ma, Zhong-Lei; Zhang, Jing

    2016-11-01

    Sulfur (S) cross-linking styrene butadiene rubber (SBR) foams show high shrinkage due to the cure reversion, leading to reduced yield and increased processing cost. In this paper, double cross-linking system by S and dicumyl peroxide (DCP) was used to decrease the shrinkage of SBR foams. Most importantly, the synergy of double cross-linking agents was reported for the first time to our knowledge. The cell size and its distribution of SBR foams were investigated by FESEM images, which show the effect of DCP content on the cell structure of the SBR foams. The relationships between shrinkage and crystalline of SBR foams were analyzed by the synergy of double cross-linking agents, which were demonstrated by FTIR, Raman spectra, XRD, DSC and TGA. When the DCP content was 0.6 phr, the SBR foams exhibit excellent physical and mechanical properties such as low density (0.223 g/cm3), reduced shrinkage (2.25%) and compression set (10.96%), as well as elevated elongation at break (1.78 × 103%) and tear strength (54.63 N/mm). The results show that these properties are related to the double cross-linking system of SBR foams. Moreover, the double cross-linking SBR foams present high electromagnetic interference (EMI) shielding properties compared with the S cross-linking SBR foams.

  6. 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.

  7. 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.

  8. 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).

  9. 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)

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  11. Proper Sizing of Circulation Pumps

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Nørgaard, Jørgen

    2007-01-01

    The paper describes the preliminary results from field tests of replacing various types of old pumps used for circulating water in heating systems in single- and double-family houses with new types of pumps. The tests were carried out in Denmark for the Danish Electricity Savings Trust......, but the results can be applied to Europe in general. Despite the small sample of houses involved in the test, 15 houses, some rather safe conclusions can be drawn from the results, which showed that newly developed pumps with power consumption around 5-8 W, can perform the task of circulating the water...... sufficiently to keep the houses satisfactorily warm during the heating season of the test. The old replaced pumps used 5-10 times more power. In Europe alone, a gradual replacement of the present vastly oversized pumps with such small but sufficient pumps can save the construction of 17 large power plants...

  12. Role of surface properties for the kinetics of bubble Ostwald ripening in saponin-stabilized foams

    NARCIS (Netherlands)

    Tcholakova, Slavka; Mustan, Fatmegul; Pagureva, Nevena; Golemanov, Konstantin; Denkov, Nikolai D.; Pelan, Edward G.; Stoyanov, Simeon D.

    2017-01-01

    Bubble Ostwald ripening (OR) leads to a gradual increase of the mean bubble size in foams with time. The rate of OR can be reduced significantly or even arrested completely using appropriate solid particles and/or surfactants as foam stabilizers. In the current paper, we show that saponins, a

  13. Liquid versus foam sclerotherapy.

    Science.gov (United States)

    Hamel-Desnos, C; Allaert, F-A

    2009-12-01

    A systematic review to compare efficacy and safety of foam (F) sclerotherapy versus liquid (L) sclerotherapy for primary varicose veins of the lower limbs. Systematic searches of electronic databases were conducted in April 2009 to identify relevant published studies. Database searches were augmented with abstracts from conference proceedings and electronic and hand searching of journals not consistently indexed in the major databases. For treatment of saphenous veins, six trials (four randomized controlled trials) were considered. Despite containing much less sclerosing agent, F was markedly more effective compared with L, the difference being put at between 20% and 50%. Four studies were included in a meta-analysis showing efficacy of F at 76.8% (95% confidence interval [CI] 71-82) versus L at 39.5% (95% CI 33-46), chi(2) = 60.9740; P reticular veins and telangiectases, only two comparative trials were found and do not at present provide any conclusive evidence to support the superiority of efficacy of one form over the other. Statistically, the side-effects reported in all the available comparative trials do not differ between F and L forms, even if visual disturbances seem to be more common with F. In the treatment of varices of the lower limbs, F shows much greater efficacy compared to L. Concerning the side effects, no statistical significant differences were found between L and F.

  14. Foam-mat drying technology: A review.

    Science.gov (United States)

    Hardy, Z; Jideani, V A

    2017-08-13

    This article reviews various aspects of foam-mat drying such as foam-mat drying processing technique, main additives used for foam-mat drying, foam-mat drying of liquid and solid foods, quality characteristics of foam-mat dried foods, and economic and technical benefits for employing foam-mat drying. Foam-mat drying process is an alternative method that allows the removal of water from liquid materials and pureed materials. In this drying process, a liquid material is converted into foam that is stable by being whipped after adding an edible foaming agent. The stable foam is then spread out in sheet or mat and dried by using hot air (40-90°C) at atmospheric pressure. Methyl cellulose (0.25-2%), egg white (3-20%), maltodextrin (0.5-05%), and gum Arabic (2-9%) are the commonly utilized additives for the foam-mat drying process at the given range, either combined together for their effectiveness or individual effect. The foam-mat drying process is suitable for heat sensitive, viscous, and sticky products that cannot be dried using other forms of drying methods such as spray drying because of the state of product. More interest has developed for foam-mat drying because of the simplicity, cost effectiveness, high speed drying, and improved product quality it provides.

  15. 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

  16. Swarm intelligence application for optimization of CO2 diffusivity in polystyrene-b-polybutadiene-b-polystyrene (SEBS) foaming

    Science.gov (United States)

    Sharudin, Rahida Wati; Ajib, Norshawalina Muhamad; Yusoff, Marina; Ahmad, Mohd Aizad

    2017-12-01

    Thermoplastic elastomer SEBS foams were prepared by using carbon dioxide (CO2) as a blowing agent and the process is classified as physical foaming method. During the foaming process, the diffusivity of CO2 need to be controlled since it is one of the parameter that will affect the final cellular structure of the foam. Conventionally, the rate of CO2 diffusion was measured experimentally by using a highly sensitive device called magnetic suspension balance (MSB). Besides, this expensive MSB machine is not easily available and measurement of CO2 diffusivity is quite complicated as well as time consuming process. Thus, to overcome these limitations, a computational method was introduced. Particle Swarm Optimization (PSO) is a part of Swarm Intelligence system which acts as a beneficial optimization tool where it can solve most of nonlinear complications. PSO model was developed for predicting the optimum foaming temperature and CO2 diffusion rate in SEBS foam. Results obtained by PSO model are compared with experimental results for CO2 diffusivity at various foaming temperature. It is shown that predicted optimum foaming temperature at 154.6 °C was not represented the best temperature for foaming as the cellular structure of SEBS foamed at corresponding temperature consisted pores with unstable dimension and the structure was not visibly perceived due to foam shrinkage. The predictions were not agreed well with experimental result when single parameter of CO2 diffusivity is considered in PSO model because it is not the only factor that affected the controllability of foam shrinkage. The modification on the PSO model by considering CO2 solubility and rigidity of SEBS as additional parameters needs to be done for obtaining the optimum temperature for SEBS foaming. Hence stable SEBS foam could be prepared.

  17. Hydrogen combustion in aqueous foams

    International Nuclear Information System (INIS)

    Baer, M.R.; Griffiths, S.K.; Shepherd, J.E.

    1982-09-01

    Water fogs are recognized as an effective means to mitigate the effects of large-scale hydrogen combustion that might accompany some loss-of-coolant nuclear reactor accidents. Fogs of sufficiently high density to produce large beneficial effects may, however, be difficult to generate and maintain. An alternate method of suspending the desired mass of water is via high expansion-ratio aqueous foams. To help assess the usefulness of aqueous foams in a mitigation plan, several open tube tests and over one hundred closed vessel tests of hydrogen/air combustion with and without foam have been conducted. Above 15% hydrogen concentration, the foam causes a significant reduction in the pressure rise. The maximum effect occurs at about 28% hydrogen (the stoichiometric limit is 29.6% hydrogen) where the peak overpressure is reduced by two and one-half. Despite this overall pressure reduction, the flame speed is increased by up to an order of magnitude for combustion in the foam and strong pressure fluctuations are observed near a hydrogen concentration of 23%

  18. Numerical modeling of foam flows

    International Nuclear Information System (INIS)

    Cheddadi, Ibrahim

    2010-01-01

    Liquid foam flows are involved in numerous applications, e.g. food and cosmetics industries, oil extraction, nuclear decontamination. Moreover, their study leads to fundamental knowledge: as it is easier to manipulate and analyse, foam is used as a model material to understand the flow of emulsions, polymers, pastes, or cell aggregates, all of which display both solid and liquid behaviour. Systematic experiments performed by Francois Graner et al. provide precise data that emphasize the non Newtonian properties of the foam. Meanwhile, Pierre Saramito proposed a visco-elasto-plastic continuous tensorial model, akin to predict the behaviour of the foam. The goal of this thesis is to understand this complex behaviour, using these two elements. We have built and validated a resolution algorithm based on a bidimensional finite elements methods. The numerical solutions are in excellent agreement with the spatial distribution of all measured quantities, and confirm the predictive capabilities of the model. The dominant parameters have been identified and we evidenced the fact that the viscous, elastic, and plastic contributions to the flow have to be treated simultaneously in a tensorial formalism. We provide a substantial contribution to the understanding of foams and open the path to realistic simulations of complex VEP flows for industrial applications. (author)

  19. 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.

  20. 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......–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 porous. The foams exhibit a thermal conductivity as lowas 38.1m...

  1. Defining and comparing vibration attributes of AlSi10 foam and CFRP coated AlSi10 foam materials

    Science.gov (United States)

    Çolak, O.; Yünlü, L.

    2017-06-01

    Now, Aluminum materials have begun being manufactured as porous structures and being used with additive composite materials through emerging manufacturing technologies. These materials those porous structures have also begun being used in many areas such as automotive and aerospace due to light-weighted structures. In addition to examining mechanical behavior of porous metallic structures, examining vibration behavior is important for defining characteristic specifications. In this study, vibration attributes belong to %80 porous AlSi10 foam and CFRP coated %80 porous AlSi10 foam are determined with modal analysis. Modal parameters such as natural frequencies and damping coefficient from frequency response functions at the end of hammer impact tests. It is found that natural frequency of CFRP coated AlSi10 foam’s is 1,14 times bigger than AlSi10 foam and damping coefficient of CFRP coated AlSi10 foam is 5 times bigger than AlSi10 foam’s with tests. Dynamic response of materials in various conditions is simulated by evaluating modal parameters with FEM. According to results of the study, CFRP coating on AlSi10 foam effect vibration damping and resonance avoidance ability positively.

  2. 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.

  3. Detection of halogenated flame retardants in polyurethane foam by particle induced X-ray emission

    Science.gov (United States)

    Maley, Adam M.; Falk, Kyle A.; Hoover, Luke; Earlywine, Elly B.; Seymour, Michael D.; DeYoung, Paul A.; Blum, Arlene; Stapleton, Heather M.; Peaslee, Graham F.

    2015-09-01

    A novel application of particle-induced X-ray emission (PIXE) has been developed to detect the presence of chlorinated and brominated flame retardant chemicals in polyurethane foams. Traditional Gas Chromatography-Mass Spectrometry (GC-MS) methods for the detection and identification of halogenated flame retardants in foams require extensive sample preparation and data acquisition time. The elemental analysis of the halogens in polyurethane foam performed by PIXE offers the opportunity to identify the presence of halogenated flame retardants in a fraction of the time and sample preparation cost. Through comparative GC-MS and PIXE analysis of 215 foam samples, excellent agreement between the two methods was obtained. These results suggest that PIXE could be an ideal rapid screening method for the presence of chlorinated and brominated flame retardants in polyurethane foams.

  4. Proper body mechanics from an engineering perspective.

    Science.gov (United States)

    Mohr, Edward G

    2010-04-01

    The economic viability of the manual therapy practitioner depends on the number of massages/treatments that can be given in a day or week. Fatigue or injuries can have a major impact on the income potential and could ultimately reach the point which causes the practitioner to quit the profession, and seek other, less physically demanding, employment. Manual therapy practitioners in general, and massage therapists in particular, can utilize a large variety of body postures while giving treatment to a client. The hypothesis of this paper is that there is an optimal method for applying force to the client, which maximizes the benefit to the client, and at the same time minimizes the strain and effort required by the practitioner. Two methods were used to quantifiably determine the effect of using "poor" body mechanics (Improper method) and "best" body mechanics (Proper/correct method). The first approach uses computer modeling to compare the two methods. Both postures were modeled, such that the biomechanical effects on the practitioner's elbow, shoulder, hip, knee and ankle joints could be calculated. The force applied to the client, along with the height and angle of application of the force, was held constant for the comparison. The second approach was a field study of massage practitioners (n=18) to determine their maximal force capability, again comparing methods using "Improper and Proper body mechanics". Five application methods were tested at three different application heights, using a digital palm force gauge. Results showed that there was a definite difference between the two methods, and that the use of correct body mechanics can have a large impact on the health and well being of the massage practitioner over both the short and long term. Copyright 2009 Elsevier Ltd. All rights reserved.

  5. Modelling of Churn-Annular foam flows

    NARCIS (Netherlands)

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

    2016-01-01

    Foam assisted lift is a deliquification method in the oil and gas industry, which aims to prevent or postpone countercurrent gas-liquid flow in maturing gas wells or to assist in removing downhole accumulated liquids. According to Nimwegen, who performed experiments with foam flows, foam

  6. 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....

  7. Viscous Control of the Foam Glass Process

    DEFF Research Database (Denmark)

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

    for several types of glasses, and carried out the foam processes at different viscosities by using CaCO3 as foaming agent to find a common optimum viscosity for all the tested glasses. We also measured the particle size distribution of the recycled cullet, and quantified the degree of foam expansion through...

  8. 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

  9. EFFECTS OF COMPRESSED AIR FOAM APPLICATION ON HEAT

    Directory of Open Access Journals (Sweden)

    Adam THOMITZEK

    2015-12-01

    Full Text Available This article evaluates the knowledge obtained in firefighting tests using compressed air foam system (CAFS within a confined space. Six experiments were conducted for verification during the cooling of rooms and the self-extinguishing effect. The simulation was for a fully developed fire within a room. The fuel was chosen to simulate ordinary combustible materials utilized in residential areas. Mantel thermocouples were placed in the rooms to record the temperature changes. Compressed air foam was first applied with a standard fire hose nozzle to the ceiling and then to the epicenter of fire. Fire extinguishing was initiated after reaching the desired temperature in the room. The temperature for the start of fire extinguishing matched the third phase of development of a fire. Fire extinguishing was terminated after no obvious signs of fire were shown in epicenter of fire. The outputs of the experiments were evaluated on the basis of the amount of time passed for the temperature to drop below the suggested limit. Individual experiments were also conducted with various different admixing foaming agents over different locations. In the experiments, it has been verified that the application of compressed air foam has a positive effect on room cooling. Use of a compressed air foaming agent does not allow for the development of steam that can scald firefighters and reduce visibility. Furthermore, the extinguishing agent used is more efficient utilizing less water flow out of the fire area.

  10. Economic and energy audit of textile foam processing

    Energy Technology Data Exchange (ETDEWEB)

    Machacek, R.

    1983-06-01

    Conventional wet processing of textiles - dyeing, or application of such surface finishes as soil and water repellents, antistatic agents, fire retardants, permanent press agents, and starch - consumes about 0.19 quadrillion Btu's of energy per year, the equivalent of 30 million barrels of oil. Because wet processing involves immersion of the fabric in a water bath, most of the energy used is in the form of heat for drying. In the newer foam finishing approach, the chemicals for surface finishes are dispersed in a mixture of water and air. The chemicals are concentrated in a relatively small amount of water, and air is injected to form a thick, stable foam. Because little water is involved, drying time and temperature may be drastically reduced. Authur D. Little, Inc., conducted an economic and energy audit of foam processing that considered the technical feasibility, reliability, energy savings, and economic incentives for using foam finishing. We monitored four plants that finish textiles (carpets, broad-woven fabrics, and tubular knits). The plants were selected by the developer of the foaming process (United Merchants and Manufacturers, Inc.) to represent a wide range of textile finishing applications.

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

    Science.gov (United States)

    Watkins, Mike R; Oliver, Richard J

    2017-07-01

    Objectives The objectives were to examine the density, bubble size distribution and durability of sodium tetradecyl sulphate foam and the consistency of production of foam by a number of different operators using the Tessari method. Methods 1% and 3% sodium tetradecyl sulphate sclerosant foam was produced by an experienced operator and a group of inexperienced operators using either a 1:3 or 1:4 liquid:air ratio and the Tessari method. The foam density, bubble size distribution and foam durability were measured on freshly prepared foam from each operator. Results The foam density measurements were similar for each of the 1:3 preparations and for each of the 1:4 preparations but not affected by the sclerosant concentration. The bubble size for all preparations were very small immediately after preparation but progressively coalesced to become a micro-foam (<250 µm) after the first 30 s up until 2 min. Both the 1% and 3% solution foams developed liquid more rapidly when made in a 1:3 ratio (37 s) than in a 1:4 ratio (45 s) but all combinations took similar times to reach 0.4 ml liquid formation. For all the experiments, there was no statistical significant difference between operators. Conclusions The Tessari method of foam production for sodium tetradecyl sulphate sclerosant is consistent and reproducible even when made by inexperienced operators. The best quality foam with micro bubbles should be used within the first minute after production.

  12. 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.

  13. 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

  14. Large proper motions in the Orion nebula

    International Nuclear Information System (INIS)

    Cudworth, K.M.; Stone, R.C.

    1977-01-01

    Several nebular features, as well as one faint star, with large proper motions were identified within the Orion nebula. The measured proper motions correspond to tangential velocities of up to approximately 70 km sec -1 . One new probable variable star was also found

  15. Ethnology and the Study of Proper Names.

    Science.gov (United States)

    Bean, Susan S.

    1980-01-01

    Discusses the importance of uncovering the universal features of proper names and relating them to different naming systems. Suggests that this viewpoint may lead to an appreciation of proper names as a sociolinguistic universal and a cultural variable, beyond the particulars on which most of the literature has focused. (MES)

  16. Economic Enpowerment of Nigerian women through proper ...

    African Journals Online (AJOL)

    This paper is an attempt to make a modest contribution on how to finance Nigerian women economic empowerment programme. It also provides certain measures of proper monitoring and channeling those resources in order to achieve the target they are meant for. The writer is of the view that if proper monitoring is done, ...

  17. Exterior foam drainage and flow regime switch in the foams.

    Science.gov (United States)

    Anazadehsayed, Abdolhamid; Rezaee, Nastaran; Naser, Jamal

    2018-02-01

    The three-dimensional flow in exterior microscale foams including the Plateau borders and nodes are investigated by solving Navier-stoke and continuity equations. First, we show the effect of the interfacial mobility and film thickness on the dimensionless mean velocity of the exterior foams. The velocity of the exterior node-PB is similar to the velocity of single exterior Plateau border. Next, we calculated the pressure difference of each element separately and obtained their hydraulic resistances. We found out that the hydraulic resistance of the exterior Plateau border is always larger than the hydraulic resistance of the exterior node, resulting in a consistent channel-dominated regime. However, For the interior foams, there is a value of interfacial mobility where the node's resistance overcomes the channel's resistance, resulting in a switch from the channel-dominated regime to a node-dominated regime. This switching point is dependent on the relative length of the channels. Hence, we obtained an approximation of the interfacial mobility switching points versus the relative length of channels. Moreover, in a form of approximation master curve, we showed the dependence of mean velocities of foams and channels' hydraulic resistances to a dimensionless combined parameter of Λ -1 that contains interfacial mobility and film thickness together. For both the exterior and interior nodes, the velocity and hydraulic resistance are almost constant for various Boussinesq numbers since interfacial mobility has a marginal effect on node's flow. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Polymeric foam-ferromagnet composites as smart lightweight materials

    International Nuclear Information System (INIS)

    D’Auria, M; Sorrentino, L; Davino, D; Pantani, R

    2016-01-01

    A new class of lightweight smart materials based on a polymeric matrix with embedded magnetic micro-particles was developed. The application of a magnetic field (MF) during the foaming of samples induced, along the MF lines, the alignment of magnetic particles dispersed in the polymer thus forming chain-like reinforcing structures. The aligned micro-particles induced an anisotropic mechanical behaviour, strongly improving the mechanical stiffness and strength along the MF direction compared to unfilled systems. Most notably, the chain-like structures imparted a magneto-sensitive behaviour to the lightweight materials. In fact, foams showed a direct relationship between the foams elastic response and the intensity as well as the shape of the time dependent MF applied during their magneto-elastic characterisation. This magneto-elastic behaviour has been obtained at low MF strength (below 200 kA m −1 ). (paper)

  19. Foaming and Antifoaming in Radioactive Waste Pretreatment and Immobilization Processes

    International Nuclear Information System (INIS)

    Wasan, Darsh T.; Nikolov, Alex D.; Lamber, D.P.; Calloway, T. Bond; Stone, M.E.

    2005-01-01

    Savannah River National Laboratory (SRNL) has reported severe foaminess in the bench scale evaporation of the Hanford River Protection - Waste Treatment Plant (RPP-WPT) envelope C waste. Excessive foaming in waste evaporators can cause carryover of radionuclides and non-radioactive waste to the condensate system. The antifoams used at Hanford and tested by SRNL are believed to degrade and become inactive in high pH solutions. Hanford wastes have been known to foam during evaporation causing excessive down time and processing delays

  20. Foam Transport in Porous Media - A Review

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-11-11

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

  1. KINERJA PENGELOLAAN LIMBAH HOTEL PESERTA PROPER DAN NON PROPER DI KABUPATEN BADUNG, PROVINSI BALI

    Directory of Open Access Journals (Sweden)

    Putri Nilakandi Perdanawati Pitoyo

    2016-07-01

    Full Text Available Bali tourism development can lead to positive and negative impacts that threatening environmental sustainability. This research evaluates the hotel performance of the waste management that includes management of waste water, emission, hazardous, and solid waste by hotel that participate at PROPER and non PROPER. Research using qualitative descriptive method. Not all of non PROPER doing test on waste water quality, chimney emissions quality, an inventory of hazardous waste and solid waste sorting. Wastewater discharge of PROPER hotels ranged from 290.9 to 571.8 m3/day and non PROPER ranged from 8.4 to 98.1 m3/day with NH3 parameter values that exceed the quality standards. The quality of chimney emissions were still below the quality standard. The volume of the hazardous waste of PROPER hotels ranged from 66.1 to 181.9 kg/month and non PROPER ranged from 5.003 to 103.42 kg/month. Hazardous waste from the PROPER hotel which has been stored in the TPS hazardous waste. The volume of the solid waste of PROPER hotel ranged from 342.34 to 684.54 kg/day and non PROPER ranged from 4.83 to 181.51 kg/day. The PROPER and non PROPER hotel not sort the solid waste. The hotel performance in term of wastewater management, emission, hazardous, and solid waste is better at the PROPER hotel compared to non PROPER participants.

  2. Fluid Physics of Foam Evolution and Flow

    Science.gov (United States)

    Aref, H.; Thoroddsen, S. T.; Sullivan, J. M.

    2003-01-01

    The grant supported theoretical, numerical and experimental work focused on the elucidation of the fluid physics of foam structure, evolution and flow. The experimental work concentrated on these subject areas: (a) Measurements of the speed of reconnections within a foam; (b) statistics of bubble rearrangements; and (c) three-dimensional reconstruction of the foam structure. On the numerical simulation and theory side our efforts concentrated on the subjects: (a) simulation techniques for 2D and 3D foams; (b) phase transition in a compressible foam; and (c) TCP structures.

  3. 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.

  4. 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.

  5. Oviduct modifications in foam-nesting frogs, with emphasis on the genus Leptodactylus (Amphibia, Leptodactylidae)

    Science.gov (United States)

    Furness, Andrew I.; McDiarmid, Roy W.; Heyer, W. Ronald; Zug, George R.

    2010-01-01

    Various species of frogs produce foam nests that hold their eggs during development. We examined the external morphology and histology of structures associated with foam nest production in frogs of the genus Leptodactylus and a few other taxa. We found that the posterior convolutions of the oviducts in all mature female foam-nesting frogs that we examined were enlarged and compressed into globular structures. This organ-like portion of the oviduct has been called a "foam gland" and these structures almost certainly produce the secretion that is beaten by rhythmic limb movements into foam that forms the nest. However, the label "foam gland" is a misnomer because the structures are simply enlarged and tightly folded regions of the pars convoluta of the oviduct, rather than a separate structure; we suggest the name pars convoluta dilata (PCD) for this feature. Although all the foam-nesters we examined had a pars convoluta dilata, its size and shape showed considerable interspecific variation. Some of this variation likely reflects differences in the breeding behaviors among species and in the size, type, and placement of their foam nests. Other variation, particularly in size, may be associated with the physiological periodicity and reproductive state of the female, her age, and/or the number of times she has laid eggs.

  6. Initial development and testing of a novel foam-based pressure sensor for wearable sensing

    Directory of Open Access Journals (Sweden)

    Smyth Barry

    2005-03-01

    Full Text Available Abstract Background This paper provides an overview of initial research conducted in the development of pressure-sensitive foam and its application in wearable sensing. The foam sensor is composed of polypyrrole-coated polyurethane foam, which exhibits a piezo-resistive reaction when exposed to electrical current. The use of this polymer-coated foam is attractive for wearable sensing due to the sensor's retention of desirable mechanical properties similar to those exhibited by textile structures. Methods The development of the foam sensor is described, as well as the development of a prototype sensing garment with sensors in several areas on the torso to measure breathing, shoulder movement, neck movement, and scapula pressure. Sensor properties were characterized, and data from pilot tests was examined visually. Results The foam exhibits a positive linear conductance response to increased pressure. Torso tests show that it responds in a predictable and measurable manner to breathing, shoulder movement, neck movement, and scapula pressure. Conclusion The polypyrrole foam shows considerable promise as a sensor for medical, wearable, and ubiquitous computing applications. Further investigation of the foam's consistency of response, durability over time, and specificity of response is necessary.

  7. Bio-based Polymer Foam from Soyoil

    Science.gov (United States)

    Bonnaillie, Laetitia M.; Wool, Richard P.

    2006-03-01

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

  8. Numerical Modeling of Foam Drilling Hydraulics

    Directory of Open Access Journals (Sweden)

    Ozcan Baris

    2007-12-01

    Full Text Available The use of foam as a drilling fluid was developed to meet a special set of conditions under which other common drilling fluids had failed. Foam drilling is defined as the process of making boreholes by utilizing foam as the circulating fluid. When compared with conventional drilling, underbalanced or foam drilling has several advantages. These advantages include: avoidance of lost circulation problems, minimizing damage to pay zones, higher penetration rates and bit life. Foams are usually characterized by the quality, the ratio of the volume of gas, and the total foam volume. Obtaining dependable pressure profiles for aerated (gasified fluids and foam is more difficult than for single phase fluids, since in the former ones the drilling mud contains a gas phase that is entrained within the fluid system. The primary goal of this study is to expand the knowledge-base of the hydrodynamic phenomena that occur in a foam drilling operation. In order to gain a better understanding of foam drilling operations, a hydrodynamic model is developed and run at different operating conditions. For this purpose, the flow of foam through the drilling system is modeled by invoking the basic principles of continuum mechanics and thermodynamics. The model was designed to allow gas and liquid flow at desired volumetric flow rates through the drillstring and annulus. Parametric studies are conducted in order to identify the most influential variables in the hydrodynamic modeling of foam flow.

  9. Flexible and Lightweight Pressure Sensor Based on Carbon Nanotube/Thermoplastic Polyurethane-Aligned Conductive Foam with Superior Compressibility and Stability.

    Science.gov (United States)

    Huang, Wenju; Dai, Kun; Zhai, Yue; Liu, Hu; Zhan, Pengfei; Gao, Jiachen; Zheng, Guoqiang; Liu, Chuntai; Shen, Changyu

    2017-12-06

    Flexible and lightweight carbon nanotube (CNT)/thermoplastic polyurethane (TPU) conductive foam with a novel aligned porous structure was fabricated. The density of the aligned porous material was as low as 0.123 g·cm -3 . Homogeneous dispersion of CNTs was achieved through the skeleton of the foam, and an ultralow percolation threshold of 0.0023 vol % was obtained. Compared with the disordered foam, mechanical properties of the aligned foam were enhanced and the piezoresistive stability of the flexible foam was improved significantly. The compression strength of the aligned TPU foam increases by 30.7% at the strain of 50%, and the stress of the aligned foam is 22 times that of the disordered foam at the strain of 90%. Importantly, the resistance variation of the aligned foam shows a fascinating linear characteristic under the applied strain until 77%, which would benefit the application of the foam as a desired pressure sensor. During multiple cyclic compression-release measurements, the aligned conductive CNT/TPU foam represents excellent reversibility and reproducibility in terms of resistance. This nice capability benefits from the aligned porous structure composed of ladderlike cells along the orientation direction. Simultaneously, the human motion detections, such as walk, jump, squat, etc. were demonstrated by using our flexible pressure sensor. Because of the lightweight, flexibility, high compressibility, excellent reversibility, and reproducibility of the conductive aligned foam, the present study is capable of providing new insights into the fabrication of a high-performance pressure sensor.

  10. 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...... variations. One way is by saturation of glass melts with gas. The other involves sintering of powdered glass under a high gas pressure resulting in glass pellets with high pressure bubbles entrapped. Reheating the glass pellets above the glass transition temperature under ambient pressure allows the bubbles...... to expand. After heat-treatment foam glass can be obtained with porosities of 80–90 %. In this study we conduct physical foaming of cathode ray tube (CRT) panel glass by sintering under high pressure (5-25 MPa) using helium, nitrogen, or argon at 640 °C (~108 Pa s). Reheating a sample in a heating...

  11. Fabrication of Gold Nanoparticles Doped DVB Foams

    International Nuclear Information System (INIS)

    Fang Yu; Luo Xuan; Fan Yongheng; Zhang Qingjun; Ren Hongbo; Xiao Lei

    2009-01-01

    The fabrication of gold nanoparticles doped low density DVB foams was researched, which can be used as ICF target materials. By high internal phase emulsion (HIPE) method, gold nanoparticles doped low density DVB foams were prepared, with gold nanoparticles dissolved in inner phase. The results show that the content of Au in the gold nanoparticles doped DVB foam is 3. 19%, the axial direction density of the foam is uniform which indicates none evident settlement of gold nanoparticles. SEM tests show that the gold doped DVB polymer foams have open-celled structure and very uniform aperture, and the average pore size is about 1 μm, which is much smaller than that of pure DVB foams. EDX test shows that Au disperses uniformly in the foams. (authors)

  12. 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.

  13. Constitutive modelling of aluminium foams

    NARCIS (Netherlands)

    Wang, W.M.; Lemmen, P.P.M.

    2001-01-01

    In this paper an aluminium foam model is proposed for a vehicle crash analysis. The model assumes that there is no coupling between stresses and strains in different principal directions. The stress in each principle direction is then interpolated from an experimental recorded uniaxial stress strain

  14. 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.

  15. Washing Off Polyurethane Foam Insulation

    Science.gov (United States)

    Burley, Richard K.; Fogel, Irving

    1990-01-01

    Jet of hot water removes material quickly and safely. Simple, environmentally sound technique found to remove polyurethane foam insulation from metal parts. Developed for (but not limited to) use during rebuilding of fuel system of Space Shuttle main engine, during which insulation must be removed for penetrant inspection of metal parts.

  16. 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

  17. Influence of foaming agents on solid thermal conductivity of foam glasses prepared from CRT panel glass

    DEFF Research Database (Denmark)

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

    2017-01-01

    The understanding of the thermal transport mechanism of foam glass is still lacking. The contribution of solid- and gas conduction to the total thermal conductivity remains to be reported. In many foam glasses, the solid phase consist of a mix of an amorphous and a crystalline part where foaming...... containing glass and crystalline foaming agents and amorphous samples where the foaming agents are completely dissolved in the glass structure, respectively. Results show that the samples prepared by sintering have a higher thermal conductivity than the samples prepared by melt-quenching. The thermal...... conductivities of the sintered and the melt-quenched samples represent an upper and lower limit of the solid phase thermal conductivity of foam glasses prepared with these foaming agents. The content of foaming agents dissolved in the glass structure has a major impact on the solid thermal conductivity of foam...

  18. Proper Treatment of Acute Mesenteric Ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Kwan; Han, Young Min [Dept. of Radiology, Chonbuk National University Hospital and School of Medicine, Jeonju (Korea, Republic of); Kwak, Hyo Sung [Research Institue of Clinical Medicine, Chonbuk National University Hospital and School of Medicine, Jeonju (Korea, Republic of); Yu, Hee Chul [Dept. of Radiology, Chonbuk National University Hospital and School of Medicine, Jeonju (Korea, Republic of)

    2011-10-15

    To evaluate the effectiveness of treatment options for Acute Mesenteric Ischemia and establish proper treatment guidelines. From January 2007 to May 2010, 14 patients (13 men and 1 woman, mean age: 52.1 years) with acute mesenteric ischemia were enrolled in this study. All of the lesions were detected by CT scan and angiography. Initially, 4 patients underwent conservative treatment. Eleven patients were managed by endovascular treatment. We evaluated the therapeutic success and survival rate of each patient. The causes of ischemia included thromboembolism in 6 patients and dissection in 8 patients. Nine patients showed bowel ischemia on CT scans, 4 dissection patients underwent conservative treatment, 3 patients had recurring symptoms, and 5 dissection patients underwent endovascular treatment. Overall success and survival rate was 100%. However, overall success was 83% and survival rate was 40% in the 6 thromboembolism patients. The choice of 20 hours as the critical time in which the procedure is ideally performed was statistically significant (p = 0.0476). A percutaneous endovascular procedure is an effective treatment for acute mesenteric ischemia, especially in patients who underwent treatment within 20 hours. However, further study and a long term follow-up are needed.

  19. Polyimide-Foam/Aerogel Composites for Thermal Insulation

    Science.gov (United States)

    Williams, Martha; Fesmire, James; Sass, Jared; Smith, Trent; Weoser. Erol

    2009-01-01

    Composites of specific types of polymer foams and aerogel particles or blankets have been proposed to obtain thermal insulation performance superior to those of the neat polyimide foams. These composites have potential to also provide enhanced properties for vibration dampening or acoustic attenuation. The specific type of polymer foam is denoted "TEEK-H", signifying a series, denoted H, within a family of polyimide foams that were developed at NASA s Langley Research Center and are collectively denoted TEEK (an acronym of the inventors names). The specific types of aerogels include Nanogel aerogel particles from Cabot Corporation in Billerica, MA. and of Spaceloft aerogel blanket from Aspen Aerogels in Northborough, MA. The composites are inherently flame-retardant and exceptionally thermally stable. There are numerous potential uses for these composites, at temperatures from cryogenic to high temperatures, in diverse applications that include aerospace vehicles, aircraft, ocean vessels, buildings, and industrial process equipment. Some low-temperature applications, for example, include cryogenic storage and transfer or the transport of foods, medicines, and chemicals. Because of thermal cycling, aging, and weathering most polymer foams do not perform well at cryogenic temperatures and will undergo further cracking over time. The TEEK polyimides are among the few exceptions to this pattern, and the proposed composites are intended to have all the desirable properties of TEEK-H foams, plus improved thermal performance along with enhanced vibration or acoustic-attenuation performance. A composite panel as proposed would be fabricated by adding an appropriate amount of TEEK friable balloons into a mold to form a bottom layer. A piece of flexible aerogel blanket material, cut to the desired size and shape, would then be placed on the bottom TEEK layer and sandwiched between another top layer of polyimide friable balloons so that the aerogel blanket would become

  20. ASTEROID PROPER ELEMENTS V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — Proper elements of asteroids are derived from the osculating orbital elements by correcting for the perturbations of the major planets to arrive at elements which...

  1. Mechanisms behind the stabilizing action of cellulose nanofibrils in wet-stable cellulose foams.

    Science.gov (United States)

    Cervin, Nicholas Tchang; Johansson, Erik; Benjamins, Jan-Willem; Wågberg, Lars

    2015-03-09

    The principal purpose of the investigation was to clarify the mechanisms behind the stabilizing action of cellulose nanofibrils (CNFs) in wet-stable cellulose foams. Following the basic theories for particle-stabilized foams, the investigation was focused on how the surface energy of the stabilizing CNF particles, their aspect ratio and charge density, and the concentration of CNF particles at the air-water interface affect the foam stability and the mechanical properties of a particle-stabilized air-liquid interface. The foam stability was evaluated from how the foam height changed over time, and the mechanical properties of the interface were evaluated as the complex viscoelastic modulus of the interface using the pendant drop method. The most important results and conclusions are that CNFs can be used as stabilizing particles for aqueous foams already at a concentration as low as 5 g/L. The major reasons for this were the small dimensions of the CNF and their high aspect ratio, which is important for gel-formation and the complex viscoelastic modulus of the particle-filled air-water interface. The influence of the aspect ratio was also demonstrated by a much higher foam stability of foams stabilized with CNFs than of foams stabilized by cellulose nanocrystals (CNC) with the same chemical composition. The charge density of the CNFs affects the level of liberation within larger aggregates and hence also the number of contact points at the interface and the gel formation and complex viscoelastic modulus of the air-water interface. The charges also result in a disjoining pressure related to the long-range repulsive electrostatic pressure between particle-stabilized bubbles and hence contribute to foam stability.

  2. Modeling foam delivery mechanisms in deep vadose-zone remediation using method of characteristics

    International Nuclear Information System (INIS)

    Roostapour, A.; Kam, S.I.

    2012-01-01

    Highlights: ► A new mathematical framework established for vadose-zone foam remediation. ► Graphical solutions presented by Method of Characteristics quantitatively. ► Effects of design parameters in the field applications thoroughly investigated. ► Implication of modeling study for successful field treatment discussed. - Abstract: This study investigates foam delivery mechanisms in vadose-zone remediation by using Method of Characteristics (MoC), a mathematical tool long been used for the analysis of miscible and immiscible flooding in porous media in petroleum industry. MoC converts the governing material-balance partial differential equations into a series of ordinary differential equations, and the resulting solutions are in a form of wave propagation (more specifically, for chemical species and phase saturations) through the system as a function of time and space. Deep vadose-zone remediation has special features compared to other conventional remediation applications. They include, not limited to, a high level of heterogeneity, a very dry initial condition with low water saturation (S w ), pollutants such as metals and radionuclides fully dissolved in groundwater, and a serious concern about downward migration during the remediation treatments. For the vadose-zone remediation processes to be successful, the injected aqueous phase should carry chemicals to react with pollutants and precipitate them for immobilization and stabilization purposes. As a result, foams are believed to be an effective means, and understanding foam flow mechanism in situ is a key to the optimal design of field applications. Results show that foam delivery mechanism is indeed very complicated, making the optimum injection condition field-specific. The five major parameters selected (i.e., initial saturation of the medium, injection foam quality, surfactant adsorption, foam strength, and foam stability) are shown to be all important, interacting with each other. Results also

  3. 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

  4. Efficacy of ethanol-based hand foams using clinically relevant amounts: a cross-over controlled study among healthy volunteers

    Directory of Open Access Journals (Sweden)

    Marschall Sigunde

    2010-03-01

    Full Text Available Abstract Background Foams containing 62% ethanol are used for hand decontamination in many countries. A long drying time may reduce the compliance of healthcare workers in applying the recommended amount of foam. Therefore, we have investigated the correlation between the applied amount and drying time, and the bactericidal efficacy of ethanol foams. Methods In a first part of tests, four foams (Alcare plus, Avagard Foam, Bode test foam, Purell Instant Hand Sanitizer containing 62% ethanol, which is commonly used in U.S. hospitals, were applied to 14 volunteers in a total of seven variations, to measure drying times. In a second part of tests, the efficacy of the established amount of foam for a 30 s application time of two foams (Alcare plus, Purell Instant Hand Sanitizer and water was compared to the EN 1500 standard of 2 × 3 mL applications of 2-propanol 60% (v/v, on hands artificially contaminated with Escherichia coli. Each application used a cross-over design against the reference alcohol with 15 volunteers. Results The mean weight of the applied foam varied between 1.78 and 3.09 g, and the mean duration to dryness was between 37 s and 103 s. The correlation between the amount of foam applied and time until hands felt dry was highly significant (p 10-reduction: 3.05 ± 0.45 and Alcare plus (3.58 ± 0.71 was significantly less effective than the reference disinfection (4.83 ± 0.89 and 4.60 ± 0.59, respectively; p 10-reduction of 2.39 ± 0.57. Conclusions When using 62% ethanol foams, the time required for dryness often exceeds the recommended 30 s. Therefore, only a small volume is likely to be applied in clinical practice. Small amounts, however, failed to meet the efficacy requirements of EN 1500 and were only somewhat more effective than water.

  5. 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...

  6. Advanced Metal Foam Structures for Outer Space

    Science.gov (United States)

    Hanan, Jay; Johnson, William; Peker, Atakan

    2005-01-01

    A document discusses a proposal to use advanced materials especially bulk metallic glass (BMG) foams in structural components of spacecraft, lunar habitats, and the like. BMG foams, which are already used on Earth in some consumer products, are superior to conventional metal foams: BMG foams have exceptionally low mass densities and high strength-to-weight ratios and are more readily processable into strong, lightweight objects of various sizes and shapes. These and other attractive properties of BMG foams would be exploited, according to the proposal, to enable in situ processing of BMG foams for erecting and repairing panels, shells, containers, and other objects. The in situ processing could include (1) generation of BMG foams inside prefabricated deployable skins that would define the sizes and shapes of the objects thus formed and (2) thermoplastic deformation of BMG foams. Typically, the generation of BMG foams would involve mixtures of precursor chemicals that would be subjected to suitable pressure and temperature schedules. In addition to serving as structural components, objects containing or consisting of BMG foams could perform such functions as thermal management, shielding against radiation, and shielding against hypervelocity impacts of micrometeors and small debris particles.

  7. Investigation of field temperature in moulds of foamed plaster

    Directory of Open Access Journals (Sweden)

    M. Pawlak

    2007-12-01

    Full Text Available Plaster moulds used in precision foundry are characterized by a very low permeability which, in the case of classic plaster moulds, equals to about 0,01÷0,02 m2/(MPa·s. One of the most effective methods for increasing the permeability is a foaming treatment. Another characteristic feature of plaster is its very good insulating power which has influence on the process of solidification and cooling of a cast and also on a knock-out property. This insulating power is a function of thermophysical properties of plaster which, in turn, depend mainly on the mineralogical composition of the mould material, its bulk density as well as on the temperature of the pouring alloy. In the case of a foamed plaster mould an increase of the degree of foaming increases its porosity which causes a change in its thermophysical properties, thereby increasing susceptibility of the mass to overheating. The susceptibility of the plaster layer surrounding the cast to overheating is favorable because it makes it easier to knock-out of the cast by immersing the hot mould in cold water. Thermal and phase tensions that are created during this process cause fast destruction of plaster. This paper describes our investigations aimed at the determination of the dependence of the mould temperature field on the time of the cast stay in the mould, as recorded in a process of an unsteady heat flow. The determined data were planned to be used for estimation of the technological properties of the plaster mould. The tests were carried out using the plaster α-Supraduro and Alkanol XC (foaming agent. The test mould had a diameter of Ø 120 mm with centrally situated mould cavity of Ø 30 mm. Plaster moulds with a degree of foaming 20; 32,5 and 45% and comparatively from non-foaming plaster were tested and their temperatures were measured at the distance x=2; 9; 21; 25;27; 30 mm from the mould cavity within 25 min. Analysis of the results leads to the conclusion, that the highest

  8. Proper generalized decompositions an introduction to computer implementation with Matlab

    CERN Document Server

    Cueto, Elías; Alfaro, Icíar

    2016-01-01

    This book is intended to help researchers overcome the entrance barrier to Proper Generalized Decomposition (PGD), by providing a valuable tool to begin the programming task. Detailed Matlab Codes are included for every chapter in the book, in which the theory previously described is translated into practice. Examples include parametric problems, non-linear model order reduction and real-time simulation, among others. Proper Generalized Decomposition (PGD) is a method for numerical simulation in many fields of applied science and engineering. As a generalization of Proper Orthogonal Decomposition or Principal Component Analysis to an arbitrary number of dimensions, PGD is able to provide the analyst with very accurate solutions for problems defined in high dimensional spaces, parametric problems and even real-time simulation. .

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-01

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

  10. Strength Enhancement and Application Development of Carbon Foam for Thermal Management Systems

    National Research Council Canada - National Science Library

    Duston, Christopher; Watts, Roland; Seghi, Steve; Carney, Barbara

    2004-01-01

    .... Ceramic Composites Inc. has demonstrated the ability to increase the compressive strength by 2 times through the treatment of the carbon foam ligaments with a uniform silicon carbide coating, serving to enhance strength...

  11. Solar-augmented foam-mat drying of fruits

    Energy Technology Data Exchange (ETDEWEB)

    Tayeb, A.M. (El-Minia Univ. (Egypt). Faculty of Engineering)

    1994-04-01

    The foam-mat drying technique is used to dry fruit syrups into powder. Literature has indicated that solar energy has not yet been used in this field. Thus, it is the object of the present work to dry the foamed syrups of different fruits in a solar energy augmented drying unit. This leads to a saving in both energy and environmental pollution. An auxiliary heater along with a control unit, is used to ensure drying at constant temperature. Foaming is effected by suitable edible additives and in some cases a stabilizer is needed as well. The drying experiments were run on orange, lemon, grapefruit, tomatoes, strawberry, guava and apple. The results showed that foaming decreased the time of drying by 30.8-41.5% in the case of direct sun drying and by 47.1-73.2% in the case of solar drying compared to the drying time of unfoamed syrup. The study showed that the technique proves to be of sufficient efficiency and acceptability to replace spray drying. (author)

  12. Carbon Dioxide and Nitrogen Infused Compressed Air Foam for Depopulation of Caged Laying Hens

    Science.gov (United States)

    Gurung, Shailesh; White, Dima; Archer, Gregory; Styles, Darrel; Zhao, Dan; Farnell, Yuhua; Byrd, James; Farnell, Morgan

    2018-01-01

    Simple Summary Compressed air, detergent, and water make up compressed air foam. Our laboratory has previously reported that compressed air foam may be an effective method for mass depopulation of caged layer hens. Gases, such as carbon dioxide and nitrogen, have also been used for poultry euthanasia and depopulation. The objective of this study was to produce compressed air foam infused with carbon dioxide or nitrogen to compare its efficacy against foam with air and gas inhalation methods (carbon dioxide or nitrogen) for depopulation of caged laying hens. The study showed that a carbon dioxide-air mixture or 100% nitrogen can replace air to make compressed air foam. However, the foam with carbon dioxide had poor foam quality compared to the foam with air or nitrogen. The physiological stress response of hens subjected to foam treatments with and without gas infusion did not differ significantly. Hens exposed to foam with nitrogen died earlier as compared to methods such as foam with air and carbon dioxide. The authors conclude that infusion of nitrogen into compressed air foam results in better foam quality and shortened time to death as compared to the addition of carbon dioxide. Abstract Depopulation of infected poultry flocks is a key strategy to control and contain reportable diseases. Water-based foam, carbon dioxide inhalation, and ventilation shutdown are depopulation methods available to the poultry industry. Unfortunately, these methods have limited usage in caged layer hen operations. Personnel safety and welfare of birds are equally important factors to consider during emergency depopulation procedures. We have previously reported that compressed air foam (CAF) is an alternative method for depopulation of caged layer hens. We hypothesized that infusion of gases, such as carbon dioxide (CO2) and nitrogen (N2), into the CAF would reduce physiological stress and shorten time to cessation of movement. The study had six treatments, namely a negative control

  13. Efficient plasma production by intense laser irradiation of low density foam targets

    International Nuclear Information System (INIS)

    Tripathi, S.; Chaurasia, S.; Munda, D. S.; Gupta, N. K.; Dhareshwar, L. J.; Nataliya, B.

    2010-01-01

    Experimental investigations conducted on low density structured materials, such as foams have been presented in this paper. These low density foam targets having a density greater than the critical density of the laser produced plasma (ρ cr ≅3 mg·cm -3 at laser wavelength 1.06 μm) have been envisaged to have enhanced laser absorption. Experiments were done with an indigenously developed, focused 15 Joule/500 ps Nd: Glass laser at λ = 1064 nm. The focused laser intensity on the target was in the range of I≅10 13 -2x10 14 W/cm 2 . Laser absorption was determined by energy balance experiments. Laser energy absorption was observed to be higher than 85%. In another set of experiments, low density carbon foam targets of density 150 mg/cc were compared with the solid carbon targets. The x-ray emission in the soft x-ray region was observed to increase in foam target by about 1.8 times and 2.3 times in carbon foam and Pt doped foam as compared to solid carbon. Further, investigations were also carried out to measure the energy transmitted through the sub-critical density TAC foam targets having a density less than 3 mg/cc. Such targets have been proposed to be used for smoothening of intensity ripples in a high power laser beam profile. Transmission exceeding 1.87% has been observed and consistent with results from other laboratories.

  14. Experimental investigation of solidification in metal foam enhanced phase change material

    Science.gov (United States)

    Beyne, W.; Bağci, O.; Huisseune, H.; Canière, H.; Danneels, J.; Daenens, D.; De Paepe, M.

    2017-10-01

    A major challenge for the use of phase change materials (PCMs) in thermal energy storage (TES) is overcoming the low thermal conductivity of PCM’s. The low conductivity gives rise to limited power during charging and discharging TES. Impregnating metal foam with PCM, however, has been found to enhance the heat transfer. On the other hand, the effect of foam parameters such as porosity, pore size and material type has remained unclear. In this paper, the effect of these foam parameters on the solidification time is investigated. Different samples of PCM-impregnated metal foam were experimentally tested and compared to one without metal foam. The samples varied with respect to choice of material, porosity and pore size. They were placed in a rectangular cavity and cooled from one side using a coolant flowing through a cold plate. The other sides of the rectangular cavity were Polymethyl Methacrylate (PM) walls exposed to ambient. The temperature on the exterior walls of the cavity was monitored as well as the coolant flow rate and its temperature. The metal foam inserts reduced the solidification times by at least 25 %. However, the difference between the best performing and worst performing metal foam is about 28 %. This shows a large potential for future research.

  15. Fabrication of Aluminum Foams with Small Pore Size by Melt Foaming Method

    Science.gov (United States)

    Cheng, Ying; Li, Yanxiang; Chen, Xiang; Shi, Tong; Liu, Zhiyong; Wang, Ningzhen

    2017-04-01

    This article introduces an improvement to the fabrication of aluminum foams with small pore size by melt foaming method. Before added to the melt, the foaming agent (titanium hydride) was pretreated in two steps. It firstly went through the traditional pre-oxidation treatment, which delayed the decomposition of titanium hydride and made sure the dispersion stage was controllable. Then such pre-oxidized titanium hydride powder was mixed with copper powder in a planetary ball mill. This treatment can not only increase the number of foaming agent particles and make them easier to disperse in the melt, which helps to increase the number of pores, but also reduce the amount of hydrogen released in the foaming stage. Therefore, the pore size could be decreased. Using such a ball-milled foaming agent in melt foaming method, aluminum foams with small pore size (average size of 1.6 mm) were successfully fabricated.

  16. The effect of water binder ratio and fly ash on the properties of foamed concrete

    Science.gov (United States)

    Saloma, Hanafiah, Urmila, Dea

    2017-11-01

    Foamed concrete is a lightweight concrete composed by cement, water, fine aggregate and evenly distributed foam. Foamed concrete is produced by adding foam to the mixture. The function of foam is to create air voids in the mixture, so the weight of the concrete becomes lighter. The foaming agent is diluted in water then given air pressure by foam generator to produce foam. This research utilizes coal combustion, which is fly ash as cementitious material with a percentage of 0%, 10%, 15%, and 20%. The purpose of the research is to examine the effect of water binder ratio 0.425, 0.450, 0.475, and 0.500 using fly ash on the properties of foamed concrete. Fresh concrete tests include slump flow and setting time test while hardened concrete tests include density and compressive strength. The maximum value of slump flow test result is 59.50 cm on FC-20-0.500 mixture with w/b = 0.500 and 20% of fly ash percentage. The results of the setting time tests indicate the fastest initial and final time are 335 and 720 minutes, respectively on FC-0-0.425 mixture with w/b = 0.425 without fly ash. The lowest density is 978.344 kg/m3 on FC-20-0.500 mixture with w/b = 0.500 and 20% of fly ash percentage. The maximum compressive strength value is 4.510 MPa at 28 days on FC-10-0.450 mixture with w/b = 0.450 and 10% of fly ash percentage.

  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. LOST FOAM CASTING OF MAGNESIUM ALLOYS

    Energy Technology Data Exchange (ETDEWEB)

    Han, Qingyou [ORNL; Dinwiddie, Ralph Barton [ORNL; Sklad, Philip S [ORNL; Currie, Kenneth [Tennessee Technological University; Abdelrahman, Mohamed [Tennessee Technological University; Vondra, Fred [Tennessee Technological University; Walford, Graham [Walford Technologies; Nolan, Dennis J [Foseco-Morval

    2007-01-01

    The lost foam casting process has been successfully used for making aluminum and cast iron thin walled castings of complex geometries. Little work has been carried out on cast magnesium alloys using the lost foam process. The article describes the research activities at Oak Ridge National Laboratory and Tennessee Technological University on lost foam casting of magnesium alloys. The work was focused on castings of simple geometries such as plate castings and window castings. The plate castings were designed to investigate the mold filling characteristics of magnesium and aluminum alloys using an infrared camera. The pate castings were then characterized for porosity distribution. The window castings were made to test the castability of the alloys under lost foam conditions. Significant differences between lost foam aluminum casting and lost foam magnesium casting have been observed.

  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. ALUHAB — The Superior Aluminium Foam

    Science.gov (United States)

    Babcsan, N.; Beke, S.; Makk, P.; Soki, P.; Számel, Gy; Degischer, H. P.; Mokso, R.

    A new metal foaming technology has been developed to produce aluminum foams with controlled cell sizes, a wide range of alloy compositions, and attractive mechanical properties. ALUHAB aluminium foams are manufactured from a special foamable aluminium alloy containing ultrafine particles (80-3000 nm). The technology uses high temperature ultrasonication to homogeneously disperse the particles and thus create a stable, foamable aluminum melt. Oscillating gas injector (loud-nozzle) technology permits the injection of optimally sized bubbles into the melt that are independent of the injector orifice diameter. Using this direct gas injection method, bubble size is regulated by the frequency and the power of the ultrasound, producing uniform bubble sizes in the sub-millimeter range. The technology results in extremely stable metal foams which can be cast into complex forms and re-melted without loss of foam integrity. Processing methods and properties of the ALUHAB foams will be discussed.

  1. Spinfoam cosmology with the proper vertex amplitude

    Science.gov (United States)

    Vilensky, Ilya

    2017-11-01

    The proper vertex amplitude is derived from the Engle-Pereira-Rovelli-Livine vertex by restricting to a single gravitational sector in order to achieve the correct semi-classical behaviour. We apply the proper vertex to calculate a cosmological transition amplitude that can be viewed as the Hartle-Hawking wavefunction. To perform this calculation we deduce the integral form of the proper vertex and use extended stationary phase methods to estimate the large-volume limit. We show that the resulting amplitude satisfies an operator constraint whose classical analogue is the Hamiltonian constraint of the Friedmann-Robertson-Walker cosmology. We find that the constraint dynamically selects the relevant family of coherent states and demonstrate a similar dynamic selection in standard quantum mechanics. We investigate the effects of dynamical selection on long-range correlations.

  2. rhoCentralRfFoam: An OpenFOAM solver for high speed chemically active flows - Simulation of planar detonations -

    Science.gov (United States)

    Gutiérrez Marcantoni, L. F.; Tamagno, J.; Elaskar, S.

    2017-10-01

    A new solver developed within the framework of OpenFOAM 2.3.0, called rhoCentralRfFoam which can be interpreted like an evolution of rhoCentralFoam, is presented. Its use, performing numerical simulations on initiation and propagation of planar detonation waves in combustible mixtures H2-Air and H2-O2-Ar, is described. Unsteady one dimensional (1D) Euler equations coupled with sources to take into account chemical activity, are numerically solved using the Kurganov, Noelle and Petrova second order scheme in a domain discretized with finite volumes. The computational code can work with any number of species and its corresponding reactions, but here it was tested with 13 chemically active species (one species inert), and 33 elementary reactions. A gaseous igniter which acts like a shock-tube driver, and powerful enough to generate a strong shock capable of triggering exothermic chemical reactions in fuel mixtures, is used to start planar detonations. The following main aspects of planar detonations are here, treated: induction time of combustible mixtures cited above and required mesh resolutions; convergence of overdriven detonations to Chapman-Jouguet states; detonation structure (ZND model); and the use of reflected shocks to determine induction times experimentally. The rhoCentralRfFoam code was verified comparing numerical results and it was validated, through analytical results and experimental data.

  3. Computing Proper Equilibria of Zero-Sum Games

    DEFF Research Database (Denmark)

    Miltersen, Peter Bro; Sørensen, Troels Bjerre

    2007-01-01

    We show that a proper equilibrium of a matrix game can be found in polynomial time by solving a linear (in the number of pure strategies of the two players) number of linear programs of roughly the same dimensions as the standard linear programs describing the Nash equilibria of the game....

  4. 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.

  5. FoAM Kernow Activity Report 2016

    OpenAIRE

    Griffiths, Amber; Griffiths, David

    2016-01-01

    This review shows selected projects from the FoAM Kernow studio in 2016. FoAM is a network of transdisciplinary labs at the intersection of art, science, nature and everyday life. FoAM’s members are generalists - people who work across disparate fields in an entangled, speculative culture. Research and creative projects at FoAM combine elements of futurecrafting, citizen science, prototyping, experience design and process facilitation to re-imagine possible futures, and artistic experime...

  6. FoAM Kernow Activity Report 2017

    OpenAIRE

    Griffiths, Amber; Weatherill, Aidan; Griffiths, David

    2017-01-01

    This review shows selected projects from the FoAM Kernow studio in 2017. FoAM is a network of transdisciplinary labs at the intersection of art, science, nature and everyday life. FoAM’s members are generalists - people who work across disparate fields in an entangled, speculative culture. Research and creative projects at FoAM combine elements of futurecrafting, citizen science, prototyping, experience design and process facilitation to re-imagine possible futures.

  7. Halogen-free flame retardant polyolefin foams

    OpenAIRE

    Redondo Realinho, Vera Cristina de; Antunes, Marcelo de Sousa Pais; Santana Pérez, Orlando Onofre; Velasco Perero, José Ignacio

    2012-01-01

    The present work deals with the preparation and characterizacion of an improved fire-resistant ethylene-acrylate foamed material containing calcium carbonate and a silicon elastomer. This grade, usually employed on the cable industry sector, was modified two differents synergistic FR systems : silica/zinc borate (S/ZB) and montmorillonite/graphite nanoplatelets(N). The different formulations were prepared by melt-blending and the foams by a compression-molding foaming process using Azodicarbo...

  8. NATURAL FIBER REINFORCED POLYURETHANE RIGID FOAM

    OpenAIRE

    Seydibeyoglu, M.Ozgur; Demiroğlu, Sibel; Erdoğan, Fatma; Akın, Ecem; Ayvalık, Aynur; Karavana, Hüseyin Ata

    2017-01-01

    The main objective of this study was to prepare polyurethane foam reinforced with local Turkish natural resources. In this work, olive kernel and nutshell fibers were used for reinforcing the polyurethane foam. In order to characterize reinforced polyurethane samples, mechanical, chemical, thermal, and morphological methods were used. Mechanical properties of polyurethane foam were measured by compression test. With compression test, it was observed that compressive strength of polyurethane f...

  9. Understanding and Predicting Foam in Anaerobic Digester

    OpenAIRE

    I. R. Kanu; T. J. Aspray; A. J. Adeloye

    2015-01-01

    As a result of the ambiguity and complexity surrounding anaerobic digester foaming, efforts have been made by various researchers to understand the process of anaerobic digester foaming so as to proffer a solution that can be universally applied rather than site specific. All attempts ranging from experimental analysis to comparative review of other process has not fully explained the conditions and process of foaming in anaerobic digester. Studying the current available ...

  10. A Study of the Crystallization, Melting, and Foaming Behaviors of Polylactic Acid in Compressed CO2

    Directory of Open Access Journals (Sweden)

    Chul B. Park

    2009-12-01

    Full Text Available The crystallization and melting behaviors of linear polylactic acid (PLA treated by compressed CO2 was investigated. The isothermal crystallization test indicated that while PLA exhibited very low crystallization kinetics under atmospheric pressure, CO2 exposure significantly increased PLA’s crystallization rate; a high crystallinity of 16.5% was achieved after CO2 treatment for only 1 min at 100 °C and 6.89 MPa. One melting peak could be found in the DSC curve, and this exhibited a slight dependency on treatment times, temperatures, and pressures. PLA samples tended to foam during the gas release process, and a foaming window as a function of time and temperature was established. Based on the foaming window, crystallinity, and cell morphology, it was found that foaming clearly reduced the needed time for PLA’s crystallization equilibrium.

  11. Organic pollutant loading and biodegradability of firefighting foam

    Science.gov (United States)

    Zhang, Xian-Zhong; Bao, Zhi-ming; Hu, Cheng; Li-Shuai, Jing; Chen, Yang

    2017-11-01

    Firefighting foam has been widely used as the high-performance extinguishing agent in extinguishing the liquid poor fire. It was concerned for its environmental impacts due to its massive usage. In this study, the organic loading level and the biodegradability of 18 firefighting foams commonly used in China were evaluated and compared. The COD and TOC of firefighting foam concentrates are extremely high. Furthermore, those of foam solutions are also much higher than regular wastewater. The COD/TOC ratio of synthetic foams are higher than protein foams. The 28-day biodegradation rates of 18 firefighting foams are all over 60%, indicating that they are all ready biodegradable. Protein foams (P, FP and FFFP) have the higher organic loading and lower 28-day biodegradation rates compared to the synthetic foams (Class A foam, AFFF and S). The short and long-term impact of protein foams on the environment are larger than synthetic foams.

  12. Role of foam drainage in producing protein aggregates in foam fractionation.

    Science.gov (United States)

    Li, Rui; Zhang, Yuran; Chang, Yunkang; Wu, Zhaoliang; Wang, Yanji; Chen, Xiang'e; Wang, Tao

    2017-10-01

    It is essential to obtain a clear understanding of the foam-induced protein aggregation to reduce the loss of protein functionality in foam fractionation. The major effort of this work is to explore the roles of foam drainage in protein aggregation in the entire process of foam fractionation with bovine serum albumin (BSA) as a model protein. The results show that enhancing foam drainage increased the desorption of BSA molecules from the gas-liquid interface and the local concentration of desorbed molecules in foam. Therefore, it intensified the aggregation of BSA in foam fractionation. Simultaneously, it also accelerated the flow of BSA aggregates from rising foam into the residual solution along with the drained liquid. Because enhancing foam drainage increased the relative content of BSA molecules adsorbed at the gas-liquid interface, it also intensified the aggregation of BSA during both the defoaming process and the storage of the foamate. Furthermore, enhancing foam drainage more readily resulted in the formation of insoluble BSA aggregates. The results are highly important for a better understanding of foam-induced protein aggregation in foam fractionation. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. 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...

  14. Thermal performance enhancement of erythritol/carbon foam composites via surface modification of carbon foam

    Science.gov (United States)

    Li, Junfeng; Lu, Wu; Luo, Zhengping; Zeng, Yibing

    2017-03-01

    The thermal performance of the erythritol/carbon foam composites, including thermal diffusivity, thermal capacity, thermal conductivity and latent heat, were investigated via surface modification of carbon foam using hydrogen peroxide as oxider. It was found that the surface modification enhanced the wetting ability of carbon foam surface to the liquid erythritol of the carbon foam surface and promoted the increase of erythritol content in the erythritol/carbon foam composites. The dense interfaces were formed between erythritol and carbon foam, which is due to that the formation of oxygen functional groups C=O and C-OH on the carbon surface increased the surface polarity and reduced the interface resistance of carbon foam surface to the liquid erythritol. The latent heat of the erythritol/carbon foam composites increased from 202.0 to 217.2 J/g through surface modification of carbon foam. The thermal conductivity of the erythritol/carbon foam composite before and after surface modification further increased from 40.35 to 51.05 W/(m·K). The supercooling degree of erythritol also had a large decrease from 97 to 54 °C. Additionally, the simple and effective surface modification method of carbon foam provided an extendable way to enhance the thermal performances of the composites composed of carbon foams and PCMs.

  15. Melt Processing and Characterization of Al-SiC Nanocomposite, Al, and Mg Foam Materials

    Directory of Open Access Journals (Sweden)

    Ahmed M. Nabawy

    2016-05-01

    Full Text Available In the present work, metallic foams of Al, Mg and an Al-SiC nanocomposite (MMNC have been fabricated using a new manufacturing technique by employing melt infiltration assisted with an electromagnetic force. The aim of this investigation was to study and to develop a reliable manufacturing technique consisting of different types of metallic foams. In this technique, an electromagnetic force was used to assist the infiltration of Al-SiC slurry and of pure liquid metal into a leachable pattern of NaCl, thus providing perfect cellular structures with micro-sized porosities. A high frequency induction coil unit equipped with a vacuum chamber and a hydraulic press was used to manufacture the foam materials. Microstructures of the produced foam materials were explored by using Field Emission Scanning Electron Microscopy (FESEM. The mechanical behavior of the manufactured foams was investigated by applying compression testing. The results indicate a high applicability of the new technique in producing metallic foams of pure metals and of a metal matrix nanocomposite . The produced foam materials displayed isotropic cellular structures with excellent compressive behaviors. Microstructure measurements indicate that the average pore size and strut thickness that can be achieved are in the ranges of 100–500 μm and 50–100 μm, respectively. The produced foam of the Al-SiC nanocomposite material provided the highest strength of 50 MPa prior to the densification stage, which equates to 25 times, and 10 times higher than the strength levels that were obtained by Al, and Mg foams, respectively.

  16. Faraday instability at foam-water interface.

    Science.gov (United States)

    Bronfort, A; Caps, H

    2012-12-01

    A nearly two-dimensional foam is generated inside a Hele-shaw cell and left at rest on its liquid bath. The system is then vertically shaken and, above a well-defined acceleration threshold, surface waves appear at the foam-liquid interface. Those waves are shown to be subharmonic. The acceleration threshold is studied and compared to the common liquid-gas case, emphasizing the energy dissipation inside the foam. An empirical model is proposed for this energy loss, accounting for the foam characteristics such as the bubble size but also the excitation parameter, namely the linear velocity.

  17. Impact performance of nanophased foam core sandwich composites

    Energy Technology Data Exchange (ETDEWEB)

    Hosur, M.V. [Center for Advanced Materials, Tuskegee University, Tuskegee, AL 36088 (United States)], E-mail: mhosur@gmail.com; Mohammed, A.A.; Zainuddin, S.; Jeelani, S. [Center for Advanced Materials, Tuskegee University, Tuskegee, AL 36088 (United States)

    2008-12-20

    In this study, sandwich panels were fabricated with neat and nanophased foam core and three-layered plain weave carbon fabric/Sc-15 epoxy composite face sheets. Neat and nanophased foam cores with Nanocor I-28E nanoclay at a loading of 0.5% and 1% by weight were prepared. Sandwich panels were then fabricated using co-injection resin transfer molding process. Samples of size 100 mm x 100 mm were then cut from the panels and subjected to low-velocity impact loading using an instrumented impact test setup. Impact response of the panels was recorded and analyzed in terms of peak load, absorbed energy, time and deflection at peak load. The tested samples were then sectioned into two halves and scanned using a scanner, optical and scanning electron microscopes to understand the failure patterns. Samples with nanophased foam sustained higher loads and had lower damage areas as compared with neat counterparts. Nanophased foam cores exhibited relatively more brittle fracture.

  18. Uncertainty Analysis of Decomposing Polyurethane Foam

    Science.gov (United States)

    Hobbs, Michael L.; Romero, Vicente J.

    2000-01-01

    Sensitivity/uncertainty analyses are necessary to determine where to allocate resources for improved predictions in support of our nation's nuclear safety mission. Yet, sensitivity/uncertainty analyses are not commonly performed on complex combustion models because the calculations are time consuming, CPU intensive, nontrivial exercises that can lead to deceptive results. To illustrate these ideas, a variety of sensitivity/uncertainty analyses were used to determine the uncertainty associated with thermal decomposition of polyurethane foam exposed to high radiative flux boundary conditions. The polyurethane used in this study is a rigid closed-cell foam used as an encapsulant. Related polyurethane binders such as Estane are used in many energetic materials of interest to the JANNAF community. The complex, finite element foam decomposition model used in this study has 25 input parameters that include chemistry, polymer structure, and thermophysical properties. The response variable was selected as the steady-state decomposition front velocity calculated as the derivative of the decomposition front location versus time. An analytical mean value sensitivity/uncertainty (MV) analysis was used to determine the standard deviation by taking numerical derivatives of the response variable with respect to each of the 25 input parameters. Since the response variable is also a derivative, the standard deviation was essentially determined from a second derivative that was extremely sensitive to numerical noise. To minimize the numerical noise, 50-micrometer element dimensions and approximately 1-msec time steps were required to obtain stable uncertainty results. As an alternative method to determine the uncertainty and sensitivity in the decomposition front velocity, surrogate response surfaces were generated for use with a constrained Latin Hypercube Sampling (LHS) technique. Two surrogate response surfaces were investigated: 1) a linear surrogate response surface (LIN) and 2

  19. Modeling of Flexible Polyurethane Foam Shrinkage for Bra Cup Moulding Process Control

    Directory of Open Access Journals (Sweden)

    Long Wu

    2018-04-01

    Full Text Available Nowadays, moulding technology has become a remarkable manufacturing process in the intimate apparel industry. Polyurethane (PU foam sheets are used to mould three-dimensional (3D seamless bra cups of various softness and shapes, which eliminate bulky seams and reduce production costs. However, it has been challenging to accurately and effectively control the moulding process and bra cup thickness. In this study, the theoretical mechanism of heat transfer and the thermal conductivity of PU foams are first examined. Experimental studies are carried out to investigate the changes in foam materials at various moulding conditions (viz., temperatures, and lengths of dwell time in terms of surface morphology and thickness by using electron and optical microscopy. Based on the theoretical and experimental investigations of the thermal conductivity of the foam materials, empirical equations of shrinkage ratio and thermal conduction of foam materials were established. A regression model to predict flexible PU foam shrinkage during the bra cup moulding process was formulated by using the Levenberg-Marquardt method of nonlinear least squares algorithm and verified for accuracy. This study therefore provides an effective approach that optimizes control of the bra cup moulding process and assures the ultimate quality and thickness of moulded foam cups.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  1. Influence of high power ultrasound on rheological and foaming properties of model ice-cream mixtures

    Directory of Open Access Journals (Sweden)

    Verica Batur

    2010-03-01

    Full Text Available This paper presents research of the high power ultrasound effect on rheological and foaming properties of ice cream model mixtures. Ice cream model mixtures are prepared according to specific recipes, and afterward undergone through different homogenization techniques: mechanical mixing, ultrasound treatment and combination of mechanical and ultrasound treatment. Specific diameter (12.7 mm of ultrasound probe tip has been used for ultrasound treatment that lasted 5 minutes at 100 percent amplitude. Rheological parameters have been determined using rotational rheometer and expressed as flow index, consistency coefficient and apparent viscosity. From the results it can be concluded that all model mixtures have non-newtonian, dilatant type behavior. The highest viscosities have been observed for model mixtures that were homogenizes with mechanical mixing, and significantly lower values of viscosity have been observed for ultrasound treated ones. Foaming properties are expressed as percentage of increase in foam volume, foam stability index and minimal viscosity. It has been determined that ice cream model mixtures treated only with ultrasound had minimal increase in foam volume, while the highest increase in foam volume has been observed for ice cream mixture that has been treated in combination with mechanical and ultrasound treatment. Also, ice cream mixtures having higher amount of proteins in composition had shown higher foam stability. It has been determined that optimal treatment time is 10 minutes.

  2. Graded porous polyurethane foam: A potential scaffold for oro-maxillary bone regeneration

    International Nuclear Information System (INIS)

    Giannitelli, S.M.; Basoli, F.; Mozetic, P.; Piva, P.; Bartuli, F.N.; Luciani, F.; Arcuri, C.; Trombetta, M.; Rainer, A.; Licoccia, S.

    2015-01-01

    Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material—characterized by a dense shell and a porous core—for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cells (hBMSCs). Our findings confirm that the material is potentially suitable for guided bone regeneration applications. - Highlights: • Graded porous polyurethane foams were synthesized via a one-pot foaming reaction. • The inner porous core might act as a scaffold for guided bone regeneration. • A dense outer shell was introduced to act as a barrier to gingival tissue ingrowth. • The synthesized foams were non-toxic and supportive of hBMSC adhesion

  3. Graded porous polyurethane foam: A potential scaffold for oro-maxillary bone regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Giannitelli, S.M. [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Basoli, F. [Department of Chemical Science and Technology, University of Rome “Tor Vergata”, Rome (Italy); Mozetic, P. [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Piva, P.; Bartuli, F.N.; Luciani, F. [University of Rome “Tor Vergata”, Rome (Italy); Arcuri, C. [Department of Periodontics, University of Rome “Tor Vergata”, Rome (Italy); U.O.C.C. Odontostomatology, “S. Giovanni Calibita, Fatebenefratelli” Hospital, Rome (Italy); Trombetta, M. [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Rainer, A., E-mail: a.rainer@unicampus.it [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Licoccia, S. [Department of Chemical Science and Technology, University of Rome “Tor Vergata”, Rome (Italy)

    2015-06-01

    Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material—characterized by a dense shell and a porous core—for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cells (hBMSCs). Our findings confirm that the material is potentially suitable for guided bone regeneration applications. - Highlights: • Graded porous polyurethane foams were synthesized via a one-pot foaming reaction. • The inner porous core might act as a scaffold for guided bone regeneration. • A dense outer shell was introduced to act as a barrier to gingival tissue ingrowth. • The synthesized foams were non-toxic and supportive of hBMSC adhesion.

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

    Science.gov (United States)

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

    2018-02-01

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

  5. Strategy Guideline. Proper Water Heater Selection

    Energy Technology Data Exchange (ETDEWEB)

    Hoeschele, M. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Springer, D. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); German, A. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Staller, J. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Zhang, Y. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States)

    2015-04-09

    This Strategy Guideline on proper water heater selection was developed by the Building America team Alliance for Residential Building Innovation to provide step-by-step procedures for evaluating preferred cost-effective options for energy efficient water heater alternatives based on local utility rates, climate, and anticipated loads.

  6. Strategy Guideline: Proper Water Heater Selection

    Energy Technology Data Exchange (ETDEWEB)

    Hoeschele, M. [Alliance for Residential Building Innovation, Davis, CA (United States); Springer, D. [Alliance for Residential Building Innovation, Davis, CA (United States); German, A. [Alliance for Residential Building Innovation, Davis, CA (United States); Staller, J. [Alliance for Residential Building Innovation, Davis, CA (United States); Zhang, Y. [Alliance for Residential Building Innovation, Davis, CA (United States)

    2015-04-01

    This Strategy Guideline on proper water heater selection was developed by the Building America team Alliance for Residential Building Innovation to provide step-by-step procedures for evaluating preferred cost-effective options for energy efficient water heater alternatives based on local utility rates, climate, and anticipated loads.

  7. Improved Industrial Development In Nigeria Through Proper ...

    African Journals Online (AJOL)

    The paper noted that most industrial development strategies in Nigeria did not give attention to technology education. And that technology education as recognized by few of the strategies were not only properly articulated for the tertiary institutions, but also poorly implemented. Therefore, to put technology and thus ...

  8. Archetypes: the PropeR way

    NARCIS (Netherlands)

    van der Linden, Helma; Grimson, Jane; Tange, Huibert; Talmon, Jan; Hasman, Arie

    2004-01-01

    The PropeR project studies the effect of Decision Support in an Electronic Health Record system (EHR) on the quality of care. One of the applications supports a multidisciplinary primary care team rehabilitating stroke patients in their home environment. This project required an EHR system that

  9. Dynamical systems of proper characteristic 0

    International Nuclear Information System (INIS)

    Ahmad, K.H.; Hamoui, A.

    1991-07-01

    Flows with orbits of proper characteristics 0 exhibit recurrent behaviour, a feature of basic importance in the description of their dynamics. Here, we analyze flows with such orbits relating them with recurrent flows and with flows that exhibit orbital, Poisson or Lagrange stability. (author). 11 refs

  10. Extrusion foaming of thermoplastic cellulose acetate from renewable resources using a two-component physical blowing agent system

    Science.gov (United States)

    Hopmann, Ch.; Windeck, C.; Hendriks, S.; Zepnik, S.; Wodke, T.

    2014-05-01

    Thermoplastic cellulose acetate (CA) is a bio-based polymer with optical, mechanical and thermal properties comparable to those of polystyrene (PS). The substitution of the predominant petrol-based PS in applications like foamed food trays can lead to a more sustainable economic practice. However, CA is also suitable for more durable applications as the biodegradability rate can be controlled by adjusting the degree of substitutions. The extrusion foaming of CA still has to overcome certain challenges. CA is highly hydrophilic and can suffer from hydrolytic degradation if not dried properly. Therefore, the influence of residual moisture on the melt viscosity is rather high. Beyond, the surface quality of foam CA sheets is below those of PS due to the particular foaming behaviour. This paper presents results of a recent study on extrusion foamed CA, using a two-component physical blowing agent system compromising HFO 1234ze as blowing agent and organic solvents as co-propellant. Samples with different co-propellants are processed on a laboratory single screw extruder at IKV. Morphology and surface topography are investigated with respect to the blowing agent composition and the die pressure. In addition, relationships between foam density, foam morphology and the propellants are analysed. The choice of the co-propellant has a significant influence on melt-strength, foaming behaviour and the possible blow-up ratio of the sheet. Furthermore, a positive influence of the co-propellant on the surface quality can be observed. In addition, the focus is laid on the effect of external contact cooling of the foamed sheets after the die exit.

  11. Cumulative effects of using pin fin heat sink and porous metal foam on thermal management of lithium-ion batteries

    International Nuclear Information System (INIS)

    Mohammadian, Shahabeddin K.; Zhang, Yuwen

    2017-01-01

    Highlights: • 3D transient thermal analysis of a pouch Li-ion cell has been carried out. • Using pin fin heat sink improves the temperature reduction at low pumping powers. • Using pin fin heat sink enhances the temperature uniformity at low air flow rates. • Porous aluminum foam insertion with pin fins improves temperature reduction. • Porous aluminum foam insertion with pin fins enhances temperature uniformity. - Abstract: Three-dimensional transient thermal analysis of an air-cooled module was carried out to investigate cumulative effects of using pin fin heat sink and porous metal foam on thermal management of a Li-ion (lithium-ion) battery pack. Five different cases were designed as Case 1: flow channel without any pin fin or porous metal foam insertion, Case 2: flow channel with aluminum pin fins, Case 3: flow channel with porous aluminum foam pin fins, Case 4: fully inserted flow channel with porous aluminum foam, and Case 5: fully inserted flow channel with porous aluminum foam and aluminum pin fins. The effects of porous aluminum insertions, pin fin types, air flow inlet temperature, and air flow inlet velocity on the temperature uniformity and maximum temperature inside the battery pack were systematically investigated. The results showed that using pin fin heat sink (Case 2) is appropriate only for low air flow velocities. In addition, the use of porous aluminum pin fins or embedding porous aluminum foam inside the air flow channel (Cases 3 and 4) are not beneficial for thermal management improvement. The combination of aluminum pin fins and porous aluminum foam insertion inside the air flow channel (Case 5) is a proper option that improves both temperature reduction and temperature uniformity inside the battery cell.

  12. 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

  13. The effects of using immobilizer made of the polyurethane foam

    International Nuclear Information System (INIS)

    Kim, Yong Hwan; Chung, Sang Hwa; Kim, Hwa Young; Lim, Shin Taek; Oh, Sae Dong

    1992-01-01

    The immogilzer for control the patient movement during the radiation beam on was made of the polyurethane foam. The time consumption is abut 8 minutes for completely making the immobilizer. In this experimental study, the effects of using the individual immobilizer have shown that the patients have had always a same position with comfortable and high reproducibilities. Furthermore, it has shown the time for patient setup was decreased by using the individual patient immobilizer.

  14. The flow of a foam in a two-dimensional porous medium

    Science.gov (United States)

    Géraud, Baudouin; Jones, Siân. A.; Cantat, Isabelle; Dollet, Benjamin; Méheust, Yves

    2016-02-01

    Foams have been used for decades as displacing fluids for enhanced oil recovery and aquifer remediation, and more recently, for remediation of the vadose zone, in which case foams carry chemical amendments. Foams are better injection fluids than aqueous solutions due to their low sensitivity to gravity and because they are less sensitive to permeability heterogeneities, thus allowing a more uniform sweep. The latter aspect results from their peculiar rheology, whose understanding motivates the present study. We investigate foam flow through a two-dimensional porous medium consisting of circular obstacles positioned randomly in a horizontal transparent Hele-Shaw cell. The local foam structure is recorded in situ, which provides a measure of the spatial distribution of bubble velocities and sizes at regular time intervals. The flow exhibits a rich phenomenology including preferential flow paths and local flow nonstationarity (intermittency) despite the imposed permanent global flow rate. Moreover, the medium selects the bubble size distribution through lamella division-triggered bubble fragmentation. Varying the mean bubble size of the injected foam, its water content, and mean velocity, we characterize those processes systematically. In particular, we measure the spatial evolution of the distribution of bubble areas, and infer the efficiency of bubble fragmentation depending on the various control parameters. We furthermore show that the distributions of bubble sizes and velocities are correlated. This study sheds new light on the local rheology of foams in porous media and opens the way toward quantitative characterization of the relationship between medium geometry and foam flow properties. It also suggests that large-scale models of foam flows in the subsurface should account for the correlation between bubble sizes and velocities.

  15. Modeling foam delivery mechanisms in deep vadose-zone remediation using method of characteristics.

    Science.gov (United States)

    Roostapour, A; Kam, S I

    2012-12-01

    This study investigates foam delivery mechanisms in vadose-zone remediation by using Method of Characteristics (MoC), a mathematical tool long been used for the analysis of miscible and immiscible flooding in porous media in petroleum industry. MoC converts the governing material-balance partial differential equations into a series of ordinary differential equations, and the resulting solutions are in a form of wave propagation (more specifically, for chemical species and phase saturations) through the system as a function of time and space. Deep vadose-zone remediation has special features compared to other conventional remediation applications. They include, not limited to, a high level of heterogeneity, a very dry initial condition with low water saturation (S(w)), pollutants such as metals and radionuclides fully dissolved in groundwater, and a serious concern about downward migration during the remediation treatments. For the vadose-zone remediation processes to be successful, the injected aqueous phase should carry chemicals to react with pollutants and precipitate them for immobilization and stabilization purposes. As a result, foams are believed to be an effective means, and understanding foam flow mechanism in situ is a key to the optimal design of field applications. Results show that foam delivery mechanism is indeed very complicated, making the optimum injection condition field-specific. The five major parameters selected (i.e., initial saturation of the medium, injection foam quality, surfactant adsorption, foam strength, and foam stability) are shown to be all important, interacting with each other. Results also imply that although dry foam injection is generally recommended, too dry injection condition is found to hurt this process due to slow foam propagation. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Application of foams to the processing of fabrics. Interim report, October 1, 1977-March 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Duke, M.W.

    1979-04-01

    The primary objective of this project is to reduce the energy requirements for finishing fabrics by drastically reducing the water required to wet process the fabrics. Since less water is used, less energy is consumed in the evaporation of water. This is accomplished by replacing much of the water with air, making a foam and using it as the application medium. In the first six months of the project the practicality of foam fabric finishing on a commercial basis had been established. Limited yardage of fabrics equivalent in performance to conventionally wet finished fabrics were processed. In these mill trials, a range of foam fabric finishes including softeners, hand builders, durable press and shrink-resistant types were applied to cotton sheeting, corduroy and polyester/cellulosic blends, etc. In all cases, substantial energy savings were realized. Since the issuance of the first and second interim reports, commercial practice of foam fabric finishing continues to grow with cumulative total estimated as approaching 200,000,000 yards. A number of companies are currently using foam fabric finishing as a commercial production process. Additionally, the pilot range has been used to demonstrate foam fabric finishing to over twenty companies. The range has been used to demonstrate the foam acid dyeing of nylon carpets to several companies in this specialized area of textile processing. Active work still continues with these companies since the foam dyeing of carpets involves only about 1/5 the water used in the normal continuous dyeing of carpets. At the time of writing two carpet companies are actively working to evaluate foam dyeing on a mill scale. (LCL)

  17. 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. PMID:25560234

  18. dsmcFoam+: An OpenFOAM based direct simulation Monte Carlo solver

    Science.gov (United States)

    White, C.; Borg, M. K.; Scanlon, T. J.; Longshaw, S. M.; John, B.; Emerson, D. R.; Reese, J. M.

    2018-03-01

    dsmcFoam+ is a direct simulation Monte Carlo (DSMC) solver for rarefied gas dynamics, implemented within the OpenFOAM software framework, and parallelised with MPI. It is open-source and released under the GNU General Public License in a publicly available software repository that includes detailed documentation and tutorial DSMC gas flow cases. This release of the code includes many features not found in standard dsmcFoam, such as molecular vibrational and electronic energy modes, chemical reactions, and subsonic pressure boundary conditions. Since dsmcFoam+ is designed entirely within OpenFOAM's C++ object-oriented framework, it benefits from a number of key features: the code emphasises extensibility and flexibility so it is aimed first and foremost as a research tool for DSMC, allowing new models and test cases to be developed and tested rapidly. All DSMC cases are as straightforward as setting up any standard OpenFOAM case, as dsmcFoam+ relies upon the standard OpenFOAM dictionary based directory structure. This ensures that useful pre- and post-processing capabilities provided by OpenFOAM remain available even though the fully Lagrangian nature of a DSMC simulation is not typical of most OpenFOAM applications. We show that dsmcFoam+ compares well to other well-known DSMC codes and to analytical solutions in terms of benchmark results.

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

    Science.gov (United States)

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

    2017-11-01

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

  20. Loop quantum cosmology and spin foams

    International Nuclear Information System (INIS)

    Ashtekar, Abhay; Campiglia, Miguel; Henderson, Adam

    2009-01-01

    Loop quantum cosmology (LQC) is used to provide concrete evidence in support of the general paradigm underlying spin foam models (SFMs). Specifically, it is shown that: (i) the physical inner product in the timeless framework equals the transition amplitude in the deparameterized theory; (ii) this quantity admits a vertex expansion a la SFMs in which the M-th term refers just to M volume transitions, without any reference to the time at which the transition takes place; (iii) the exact physical inner product is obtained by summing over just the discrete geometries; no 'continuum limit' is involved; and, (iv) the vertex expansion can be interpreted as a perturbative expansion in the spirit of group field theory. This sum over histories reformulation of LQC also addresses certain other issues which are briefly summarized.

  1. Oxidation of Ce(III) in Foam Decontaminant by Ozone

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Chong Hun; Yoon, I. H.; Choi, W. K.; Moon, J. K.; Yang, H. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, J. S. [Gachon University, Seongnam (Korea, Republic of)

    2016-10-15

    A nanoparticle-based foam decontaminant is composed of a surfactant and nanoparticles for the generation and maintenance of foam, and a chemical decontamination agent made of Ce(IV) dissolved in nitric acid. Ce(IV) will be reduced to Ce(III) through the decontamination process. Oxidizing cerium(III) can be reused as a decontamination agent, Ce(IV). Oxidation treatment technology by ozone uses its strong oxidizing power. It can be regarded as an environmentally friendly process, because ozone cannot be stored and transported like other industrial gases (because it quickly decays into diatomic oxygen) and must therefore be produced on site, and used ozone can decompose immediately. The ozonation treatment of Ce(III) in foam decontaminant containing a surfactant is necessary for the effective regeneration of Ce(III). Thus, the present study was undertaken to determine the optimal conditions for ozonation treatment in the regeneration of Ce(III) into Ce(IV) in the nanoparticle-based foam decontaminant containing surfactant. This study was undertaken to determine the optimal conditions for ozonation treatment in the regeneration of Ce(III) to Ce(IV) in nanoparticle-based foam decontaminant containing a TBS surfactant. The oxidation conversion rate of Ce(III) was increased with an increase in the flow rate of the gas mixture and ozone injection amount. The oxidation time required for the 100% oxidation conversion of Ce(III) to Ce(IV) at a specific ozone injection amount can be predicted from these experimental data.

  2. Hemostatic foam from radiation-modified carboxymethyl derivative of chitosan

    International Nuclear Information System (INIS)

    Barba, Bin Jeremiah D.; Aranilla, Charito T.; Vista, Jeanina Richelle M.; Relleve, Lorna S.; Abad, Lucille V.

    2015-01-01

    A hemostatic agent or hemostat is intended to accelerate the blood clotting process when applied to a bleeding surface, such as those in military and civilian wound trauma or in surgery. Natural polymers like chitosan (Ch) has been previously used as raw material in developing hemostats owing to their bioavailability and biocompatibility. Hydrogels were made from its carboxymethylated derivate (CMCh) and were crosslinked by gamma irradiation at a dose of 30 kGy. Further processing was done by salt leaching with sodium chloride and lyophilization to produce the foam hemostat. The final products were then radiation-sterilized at 25 kGy. The use of gamma radiation for both the crosslinking and sterilization process preserves the biocompatibility of the product unlike conventional methods that may require the use of harmful and non-biocompatible chemicals. The hemostatic efficacy of the designed foam hemostats was compared to the commercially available foam hemostat, GELFOAM Sterile Compressed Sponge by Pfizer. The results showed a significantly higher efficiency of the designed products using in vitro test to determine blood clotting index and platelet adhesion capacity. Characterization by gel fraction, swelling capacity and SEM imaging indicated a hydrophilic three-dimensional network which can be attributed for the thrombogenicity of the foams produced. The foam structure can act as a physical matrix for platelet adhesion forming the mechanical plug and at the same time, rapidly absorb water thereby locally increasing the concentration of platelets and physiological coagulation factors that will contribute to quick and efficient hemostasis. The designed products will provide the healthcare and military sector with a local alternative to the commercial products which are both expensive (USD 85 per piece) and not readily accessible in the Philippine market. Further animal efficacy and biocompatibility studies are recommended to supplement the positive in vitro

  3. Industrial waste utilization for foam concrete

    Science.gov (United States)

    Krishnan, Gokul; Anand, K. B.

    2018-02-01

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

  4. Damping of liquid sloshing by foams

    Science.gov (United States)

    Sauret, A.; Boulogne, F.; Cappello, J.; Dressaire, E.; Stone, H. A.

    2015-02-01

    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 water 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, which 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 oscillations. We rationalize our experimental findings with a model that describes the foam contribution to the damping coefficient through viscous dissipation on the walls of the container. Then we extend our study to confined three-dimensional liquid foam and observe that the behavior of 2D and confined 3D systems are very similar. Thus, we conclude that only the bubbles close to the walls have a significant impact on the dissipation of energy. The possibility to damp liquid sloshing using foam is promising in numerous industrial applications such as the transport of liquefied gas in tankers or for propellants in rocket engines.

  5. Measuring Rind Thickness on Polyurethane Foam

    Science.gov (United States)

    Johnson, C.; Miller, J.; Brown, H.

    1985-01-01

    Nondestructive test determines rind thickness of polyurethane foam. Surface harness of foam measured by Shore durometer method: hardness on Shore D scale correlates well with rind thickness. Shore D hardness of 20, for example, indicates rind thickness of 0.04 inch (1 millimeter). New hardness test makes it easy to determine rind thickness of sample nondestructively and to adjust fabrication variables accordingly.

  6. Foam is a decon waste minimization tool

    International Nuclear Information System (INIS)

    Peterson, K.D.; McGlynn, J.F.; Rankin, W.N.

    1991-01-01

    The use of foam in decontamination operations offers significant reductions in waste generation. Initial use has confirmed its effectiveness. Issues being resolved at Savannah River Site (SRS) include compatibility of foam generating solutions with decontamination solutions, waste disposal, and operational safety

  7. Application of Auxetic Foam in Sports Helmets

    Directory of Open Access Journals (Sweden)

    Leon Foster

    2018-03-01

    Full Text Available This investigation explored the viability of using open cell polyurethane auxetic foams to augment the conformable layer in a sports helmet and improve its linear impact acceleration attenuation. Foam types were compared by examining the impact severity on an instrumented anthropomorphic headform within a helmet consisting of three layers: a rigid shell, a stiff closed cell foam, and an open cell foam as a conformable layer. Auxetic and conventional foams were interchanged to act as the helmet’s conformable component. Attenuation of linear acceleration was examined by dropping the combined helmet and headform on the front and the side. The helmet with auxetic foam reduced peak linear accelerations (p < 0.05 relative to its conventional counterpart at the highest impact energy in both orientations. Gadd Severity Index reduced by 11% for frontal impacts (38.9 J and 44% for side impacts (24.3 J. The conformable layer within a helmet can influence the overall impact attenuating properties. The helmet fitted with auxetic foam can attenuate impact severity more than when fitted with conventional foam, and warrants further investigation for its potential to reduce the risk of traumatic brain injuries in sport specific impacts.

  8. Low-density carbonized resorcinol-formaldehyde foams

    International Nuclear Information System (INIS)

    Kong, F.M.; Buckley, S.R.; Giles, C.L. Jr.; Haendler, B.L.; Hair, L.M.; Letts, S.A.; Overturf, G.E. III; Price, C.W.; Cook, R.C.

    1991-01-01

    This report documents research and development on resorcinol- formaldehyde-based foam materials conducted between 1986 and June 1990, when the effort was discontinued. The foams discussed are resorcinol-formaldehyde (RF) foam, carbonized RF (CRF) foam, and two composite foams, a polystyrene/RF (PS/RF) foam and its carbonized derivative (CPR). The RF foams are synthesized by the polycondensation of resorcinol with formaldehyde in a slightly basic solution. Their structure and density depend strongly on the concentration of the sodium carbonate catalyst. The have an interconnected bead structure similar to that of silica aerogels; bead sizes range from 30 to 130 Angstrom, and cell sizes are less than 0.1 μm. We have achieved densities of 16 to 200 mg/cm 3 . The RF foams can be pyrolyzed in an inert atmosphere to form a vitreous carbon foam (CRF), which has a similar microstructure but much higher mechanical strength. The PS/RF foams are obtained by filling the 2- to 3-μm cells of PS foam (a low-density hydrocarbon foam we have developed) with RF. The resultant foams have the outstanding handling and machinability of the PS foam matrix and the small cell size of RF. Pyrolyzing PS/RF foams causes depolymerization and loss of the PS; the resulting CPR foams have a structure similar to the PS foams in which CRF both replicates and fills the PS cells

  9. External foam and the post-mortem period in freshwater drowning; results from a retrospective study in Amsterdam, the Netherlands.

    Science.gov (United States)

    Reijnen, G; Buster, M C; Vos, P J E; Reijnders, U J L

    2017-11-01

    Determining the time of death of bodies recovered from water can be difficult. A feature of drowning is the presence of external foam. This study describes the presence of external foam in relation to the post-mortem period. The study utilizes a database of death reports dated between January 2011 and July 2016. For bodies recovered from fresh water, the presence or absence of external foam was noted. In this study, 112 death reports are included. Of these reports, 18 mentioned external foam, which account for 16.1% of the entire study population. In the population with a post-mortem period of less than 24 h, external foam was detected in 27.7% of cases. All 18 incidents with external foam had an estimated post-mortem period of less than 24 h. In our study, external foam was only present in freshwater drowning cases with a post-mortem period of less than 24 h. Based on this finding, the presence of external foam may be useful as an additional indicator when estimating the time of death in freshwater drowning. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  10. Assessing patient awareness of proper hand hygiene.

    Science.gov (United States)

    Busby, Sunni R; Kennedy, Bryan; Davis, Stephanie C; Thompson, Heather A; Jones, Jan W

    2015-05-01

    The authors hypothesized that patients may not understand the forms of effective hand hygiene employed in the hospital environment. Multiple studies demonstrate the importance of hand hygiene in reducing healthcare-associated infections (HAIs). Extensive research about how to improve compliance has been conducted. Patients' perceptions of proper hand hygiene were evaluated when caregivers used soap and water, waterless hand cleaner, or a combination of these. No significant differences were observed, but many patients reported they did not notice whether their providers cleaned their hands. Educating patients and their caregivers about the protection afforded by proper, consistent hand hygiene practices is important. Engaging patients to monitor healthcare workers may increase compliance, reduce the spread of infection, and lead to better overall patient outcomes. This study revealed a need to investigate the effects of patient education on patient perceptions of hand hygiene. Results of this study appear to indicate a need to focus on patient education and the differences between soap and water versus alcohol-based hand sanitizers as part of proper hand hygiene. Researchers could be asking: "Why have patients not been engaged as members of the healthcare team who have the most to lose?"

  11. 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.

  12. 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.

  13. Characterization of Steel Foams for Structural Components

    Directory of Open Access Journals (Sweden)

    Sanjay R. Arwade

    2012-11-01

    Full Text Available Experimentally measured mechanical properties of hollow sphere steel foam are the subject of this paper. The characterization of the hollow sphere foam encompasses compressive yield stress and densification strain, compressive plastic Poisson’s ratio, and compressive unloading modulus, as well as tensile elastic modulus, tensile unloading modulus, tensile yield stress, and tensile fracture strain. Shear properties are also included. These tests provide sufficient information to allow calibration of a macroscopic, continuum constitutive model. Calibrated foam plasticity parameters are tabulated, and unique feature of foam plasticity are explained. Also, initial development of mesoscale simulations, which explicitly model voids and sintered hollow spheres, is reported. This work is part of a larger effort to help the development of steel foam as a material with relevance to civil engineering applications.

  14. Oxidation behaviour of metallic glass foams

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, B.R. [Department of Materials Science and Engineering, 434 Dougherty Hall, University of Tennessee, Knoxville, TN 37996-2200 (United States)], E-mail: bbarnard@utk.edu; Liaw, P.K. [Department of Materials Science and Engineering, 434 Dougherty Hall, University of Tennessee, Knoxville, TN 37996-2200 (United States); Demetriou, M.D.; Johnson, W.L. [Department of Materials Science, Keck Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States)

    2008-08-15

    In this study, the effects of porosity on the oxidation behaviour of bulk-metallic glasses were investigated. Porous Pd- and Fe-based bulk-metallic glass (BMG) foams and Metglas ribbons were studied. Oxidizing experiments were conducted at 70 deg. C, and around 80 deg. C below glass-transition temperatures, (T{sub g}s). Scanning-electron microscopy/energy-dispersive spectroscopy (SEM/EDS) studies revealed little evidence of oxidation at 70 deg. C. Specimens exhibited greater oxidation at T{sub g} - 80 deg. C. Oxides were copper-based for Pd-based foams, Fe-, Cr-, and Mo-based for Fe-based foams, and Co-based with borosilicates likely for the Metglas. Pd-based foams demonstrated the best oxidation resistance, followed by Metglas ribbons, followed by Fe-based foams.

  15. Experimental study on nonlinear vibrating of aluminum foam using electronic speckle pattern interferometry

    Science.gov (United States)

    Yang, Fujun; Ma, Yinhang; Tao, Nan; He, Xiaoyuan

    2017-06-01

    Due to its multi properties, including excellent stiffness-to-weight and strength-to-weight ratios, closed-cell aluminum and its alloy foams become candidate materials for use in many high-technology industries, such as the automotive and aerospace industries. For the efficient use of closed-cell foams in structural applications, it is necessary and important to detailly understand their mechanical characteristics. In this paper, the nonlinear vibration responses of the cantilever beams of closed-cell aluminum foams were investigated by use of electronic speckle pattern interferometry (ESPI). The nonlinear resonant mode shapes of testing specimens under harmonic excitation were measured. It is first time to obtain from the experimental results that there exist super-harmonic responses when the cantilever beams of closed-cell aluminum foam were forced to vibrate, which was caused by its specific cellular structures.

  16. Attenuation of fluorocarbons released from foam insulation in landfills

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Dote, Yukata; Fredenslund, Anders Michael

    2007-01-01

    Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs) have been used as blowing agents (BAs) for foam insulation in home appliances and building materials, which after the end of their useful life are disposed of in landfills. The objective of this project...... was to evaluate the potential for degradation of BAs in landfills, and to develop a landfill model, which could simulate the fate of BAs in landfills. The investigation was performed by use of anaerobic microcosm studies using different types of organic waste and anaerobic digested sludge as inoculum. The BAs...... in any of the experiments within a run time of up to 200 days. The obtained degradation rate coefficients were used as input for an extended version of an existing landfill fate model incorporating a time dependent BA release from co-disposed foam insulation waste. Predictions with the model indicate...

  17. Limited-memory adaptive snapshot selection for proper orthogonal decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Oxberry, Geoffrey M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kostova-Vassilevska, Tanya [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Arrighi, Bill [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chand, Kyle [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-04-02

    Reduced order models are useful for accelerating simulations in many-query contexts, such as optimization, uncertainty quantification, and sensitivity analysis. However, offline training of reduced order models can have prohibitively expensive memory and floating-point operation costs in high-performance computing applications, where memory per core is limited. To overcome this limitation for proper orthogonal decomposition, we propose a novel adaptive selection method for snapshots in time that limits offline training costs by selecting snapshots according an error control mechanism similar to that found in adaptive time-stepping ordinary differential equation solvers. The error estimator used in this work is related to theory bounding the approximation error in time of proper orthogonal decomposition-based reduced order models, and memory usage is minimized by computing the singular value decomposition using a single-pass incremental algorithm. Results for a viscous Burgers’ test problem demonstrate convergence in the limit as the algorithm error tolerances go to zero; in this limit, the full order model is recovered to within discretization error. The resulting method can be used on supercomputers to generate proper orthogonal decomposition-based reduced order models, or as a subroutine within hyperreduction algorithms that require taking snapshots in time, or within greedy algorithms for sampling parameter space.

  18. Generation of sclerosant foams by mechanical methods increases the foam temperature.

    Science.gov (United States)

    Tan, Lulu; Wong, Kaichung; Connor, David; Fakhim, Babak; Behnia, Masud; Parsi, Kurosh

    2017-08-01

    Objective To investigate the effect of agitation on foam temperature. Methods Sodium tetradecyl sulphate and polidocanol were used. Prior to foam generation, the sclerosant and all constituent equipment were cooled to 4-25℃ and compared with cooling the sclerosant only. Foam was generated using a modified Tessari method. During foam agitation, the temperature change was measured using a thermocouple for 120 s. Results Pre-cooling all the constituent equipment resulted in a cooler foam in comparison with only cooling the sclerosant. A starting temperature of 4℃ produced average foam temperatures of 12.5 and 13.2℃ for sodium tetradecyl sulphate and polidocanol, respectively. It was also found that only cooling the liquid sclerosant provided minimal cooling to the final foam temperature, with the temperature 20 and 20.5℃ for sodium tetradecyl sulphate and polidocanol, respectively. Conclusion The foam generation process has a noticeable impact on final foam temperature and needs to be taken into consideration when creating foam.

  19. PUFoam : A novel open-source CFD solver for the simulation of polyurethane foams

    Science.gov (United States)

    Karimi, M.; Droghetti, H.; Marchisio, D. L.

    2017-08-01

    In this work a transient three-dimensional mathematical model is formulated and validated for the simulation of polyurethane (PU) foams. The model is based on computational fluid dynamics (CFD) and is coupled with a population balance equation (PBE) to describe the evolution of the gas bubbles/cells within the PU foam. The front face of the expanding foam is monitored on the basis of the volume-of-fluid (VOF) method using a compressible solver available in OpenFOAM version 3.0.1. The solver is additionally supplemented to include the PBE, solved with the quadrature method of moments (QMOM), the polymerization kinetics, an adequate rheological model and a simple model for the foam thermal conductivity. The new solver is labelled as PUFoam and is, for the first time in this work, validated for 12 different mixing-cup experiments. Comparison of the time evolution of the predicted and experimentally measured density and temperature of the PU foam shows the potentials and limitations of the approach.

  20. Structure and mechanics of solid foam

    Science.gov (United States)

    Miller, Erin Ashley

    Solid foams appear in a variety of settings, including impact absorption, sound damping, and structural components. However, the cellular structure of a solid foam allows it to deform in a much more complicated manner than a typical continuum solid material, leading to both interesting physics questions and also unique engineering challenges. There has been considerable work in the physics community in recent years with regards to non-traditional theories of elasticity, particularly in the context of disordered materials with some kind of "mesoscale" structure such as sandpiles, cytoskeletal networks in cells, and weakly interacting glasses. Here, we seek to address several issues. First, what is the structure of a solid foam and how it is similar or different from the structure of liquid froths? Second, how does the structure of solid foam affects its mechanical properties? Third, under what conditions can a continuum model be used to describe a solid foam? We address these questions using a combination of experiment and simulation. We have developed an x-ray microtomography apparatus to image foams in 3-D, and assembled a series of computational tools to enable machine vision recognition of foam structures. We present here a case study of the structure of an open-cell carbon foam sample, and compare its structure to that of a liquid froth. We have also carried out a series of solid mechanics simulations in order to observe how model disordered foam structures deform, both on the microscale and in an ensemble average. Based on this, we find that 2-D disordered model foams spontaneously form fluctuations in response to a constant strain perturbation. The fluctuation in the displacement field has a characteristic length scale of around 10 edge lengths; above this length scale, or averaged over many realizations of disorder, solid foams are well-described by continuum elasticity theory. The combination of experiment, analysis, and simulation described here can

  1. Potential production of palm oil-based foaming agent as fire extinguisher of peatlands in Indonesia: Literature review

    Science.gov (United States)

    Subekti, P.; Hambali, E.; Suryani, A.; Suryadarma, P.

    2017-05-01

    This study aims to analyze the potential aplication of of palm oil-based foaming agent as peat fires fighter in Indonesia. From literature review, it has been known that the foaming agent able to form foam to extinguish fire, wrap and refrigerate the burning peat. It is necessary to develop the production and application of foaming agent in Indonesia because peat fires occur almost every year that caused smoke haze. Potential raw material for the production of environmental friendly foaming agent as foam extinguishing for peat fires in Indonesia aong other is palm oil due to abundant availability, sustainable, and foam product easily degraded in the environment of the burnt areas. Production of foaming agent as fire-fighting in Indonesia is one alternative to reduce the time to control the fire and smog disaster impact. Application of palm oil as a raw material for fire-fighting is contribute to increase the value added and the development of palm oil downstream industry.

  2. Foaming in Electric Arc Furnace—Part II: Foaming Visualization and Comparison with Plant Trials

    Science.gov (United States)

    Chychko, Andrei; Teng, Lidong; Seetharaman, Seshadri

    2012-10-01

    The kinetics of slag foaming by limestone particles was studied at 1773 K (1500 °C) with the aid of an X-ray imaging system. Two models were implemented to describe the decrease in foam height with the time on the basis of the lowering of the average temperature and CaO shell formation during decomposition reaction. The energy impact of carbonate additions was studied on an industrial scale in a 100-ton electric arc furnace (EAF). It was found that, in the case of the addition of carbonates after the scrap is completely molten, the heat effects for limestone and dolomite (2255 and 2264 kJ/kg, respectively) were only 70 pct from theoretical values. Comparing these values with similar additions during the scrap melting stage shows that the energy requirements in the case of carbonate additions to steel bath are much smaller. It was found from the trial heats with dolomite addition to the steel bath that the partial substitution of lime by raw dolomite can be made without an increase in energy consumption.

  3. Computation of asteroid proper elements on the Grid

    Directory of Open Access Journals (Sweden)

    Novaković B.

    2009-01-01

    Full Text Available A procedure of gridification of the computation of asteroid proper orbital elements is described. The need to speed up the time consuming computations and make them more efficient is justified by the large increase of observational data expected from the next generation all sky surveys. We give the basic notion of proper elements and of the contemporary theories and methods used to compute them for different populations of objects. Proper elements for nearly 70,000 asteroids are derived since the beginning of use of the Grid infrastructure for the purpose. The average time for the catalogs update is significantly shortened with respect to the time needed with stand-alone workstations. We also present basics of the Grid computing, the concepts of Grid middleware and its Workload management system. The practical steps we undertook to efficiently gridify our application are described in full detail. We present the results of a comprehensive testing of the performance of different Grid sites, and offer some practical conclusions based on the benchmark results and on our experience. Finally, we propose some possibilities for the future work.

  4. Computation of Asteroid Proper Elements on the Grid

    Directory of Open Access Journals (Sweden)

    Novaković, B.

    2009-12-01

    Full Text Available A procedure of gridification of the computation of asteroid proper orbital elements is described. The need to speed up the time consuming computations and make them more efficient is justified by the large increase of observational data expected from the next generation all sky surveys. We give the basic notion of proper elements and of the contemporary theories and methods used to compute them for different populations of objects. Proper elements for nearly 70,000 asteroids are derived since the beginning of use of the Grid infrastructure for the purpose. The average time for the catalogs update is significantly shortened with respect to the time needed with stand-alone workstations. We also present basics of the Grid computing, the concepts of Grid middleware and its Workload management system. The practical steps we undertook to efficiently gridify our application are described in full detail. We present the results of a comprehensive testing of the performance of different Grid sites, and offer some practical conclusions based on the benchmark results and on our experience. Finally, we propose some possibilities for the future work.

  5. Mechanical Characterization of Lightweight Foamed Concrete

    Directory of Open Access Journals (Sweden)

    Marcin Kozłowski

    2018-01-01

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

  6. Ultra-stable self-foaming oils.

    Science.gov (United States)

    Binks, Bernard P; Marinopoulos, Ioannis

    2017-05-01

    This paper is concerned with the foaming of a range of fats in the absence of added foaming agent/emulsifier. By controlling the temperature on warming from the solid or cooling from the melt, crystals of high melting triglycerides form in a continuous phase of low melting triglycerides. Such crystal dispersions in oil can be aerated to produce whipped oils of high foamability and extremely high stability. The foams do not exhibit drainage and bubbles neither coarsen nor coalesce as they become coated with solid crystals. The majority of the findings relate to coconut oil but the same phenomenon occurs in shea butter, cocoa butter and palm kernel stearin. For each fat, there exists an optimum temperature for foaming at which the solid fat content reaches up to around 30%. We demonstrate that the oil foams are temperature-responsive and foam collapse can be controllably triggered by warming the foam to around the melting point of the crystals. Our hypothesis is given credence in the case of the pure system of tristearin crystals in liquid tricaprylin. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. 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.

  8. [Experimental Study of PMI Foam Composite Properties in Terahertz].

    Science.gov (United States)

    Xing, Li-yun; Cui, Hong-liang; Shi, Chang-cheng; Han, Xiao-hui; Zhang, Zi-yin; Li, Wei; Ma, Yu-ting; Zheng, Yan; Zhang, Song-nian

    2015-12-01

    Polymethacrylimide (PMI) foam composite has many excellent properties. Currently, PMI is heat-resistant foam, with the highest strength and stiffness. It is suitable as a high-performance sandwich structure core material. It can replace the honeycomb structure. It is widely used in aerospace, aviation, military, marine, automotive and high-speed trains, etc. But as new sandwich materials, PMI performance testing in the THz band is not yet visible. Based on the Terahertz (THz) time-domain spectroscopy technique, we conducted the transmission and reflection experiments, got the time domain waveforms and power density spectrum. And then we analyzed and compared the signals. The MATALB and Origin 8. 0 was used to calculate and obtain the transmittance (transfer function), absorptivity Coefficient, reflectance and the refractive index of the different thickness Degussa PMI (Model: Rohacell WF71), which were based on the application of the time-domain and frequency-domain analysis methods. We used the data to compared with the THz refractive index and absorption spectra of a domestic PMI, Baoding Meiwo Technology Development Co. , Ltd. (Model: SP1D80-P-30). The result shows that the impact of humidity on the measurement results is obvious. The refractive index of PMI is about 1. 05. The attenuation of power spectrum is due to the signal of the test platform is weak, the sample is thick and the internal scattering of PMI foam microstructure. This conclusion provides a theoretical basis for the THz band applications in the composite PMI. It also made a good groundwork for THz NDT (Non-Destructive Testing, NDT) technology in terms of PMI foam composites.

  9. Assigned value improves memory of proper names.

    Science.gov (United States)

    Festini, Sara B; Hartley, Alan A; Tauber, Sarah K; Rhodes, Matthew G

    2013-01-01

    Names are more difficult to remember than other personal information such as occupations. The current research examined the influence of assigned point value on memory and metamemory judgements for names and occupations to determine whether incentive can improve recall of proper names. In Experiment 1 participants studied face-name and face-occupation pairs assigned 1 or 10 points, made judgements of learning, and were given a cued recall test. High-value names were recalled more often than low-value names. However, recall of occupations was not influenced by value. In Experiment 2 meaningless nonwords were used for both names and occupations. The name difficulty disappeared, and value influenced recall of both names and occupations. Thus value similarly influenced names and occupations when meaningfulness was held constant. In Experiment 3 participants were required to use overt rote rehearsal for all items. Value did not boost recall of high-value names, suggesting that differential processing could not be implemented to improve memory. Thus incentives may improve memory for proper names by motivating people to engage in selective rehearsal and effortful elaborative processing.

  10. Solar grounds for the production of foamed concrete items

    Directory of Open Access Journals (Sweden)

    Dauzhanov Nabi Tokmurzaevich

    2014-04-01

    Full Text Available The method and low-energy intensive technology of manufacturing products of foamed concrete are developed providing bringing-in a solar energy in technological conversion for reducing the energy consumption for heat treating, allowing to obtain high quality products at low cost with a diurnal cycle of production. Thereby, the use of a minimal amount of additional electrical energy is stipulated for providing a consistence of temperature fields in the cross section of helio heated products in landfills in combination with solar energy. Until now, many scientists have investigated the issues of using the renewable energy resources in the construction industry including solar ones, for replacement of conventional fuels applied in the thermal treatment of concrete products and structures. However, pursuant to the analysis of the scientific literature, all known research studies and developments in this area are devoted to heliothermal treatment of conventional concrete, and at the same time the traditional methods for acceleration of hardening requiring significant energy consumption are still in use in production of such an effective building material as foam concrete. There are various methods of heliothermal treatment including combined ones, but they are not applicable in their production due to the specific characteristics (unlike conventional concrete of manufacturing technology, the used components, the particular rheological properties, as well as a porous structure of foam concrete. Both the examining the use of solar energy in acceleration of foam concrete hardening according to the literature data and the pre-studies have revealed a problem under unilateral heliothermal treatment of foam concrete. It is found out that the temperature field of across thickness of the massif, especially during the first 7-8 hours, is irregular, that significantly affects the process of heating moisture transfer occurring within the massif. According to the

  11. Rigid Polyurethane Foam Reinforced Coconut Coir Fiber Properties

    OpenAIRE

    Mohd Azham Azmi

    2012-01-01

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

  12. Structural Foams of Biobased Isosorbide-Containing Copolycarbonate

    OpenAIRE

    Zepnik, Stefan; Sander, Daniel; Kabasci, Stephan; Hopmann, Christian

    2017-01-01

    Isosorbide-containing copolycarbonate (Bio-PC) is a partly biobased alternative to conventional bisphenol A (BPA) based polycarbonate (PC). Conventional PC is widely used in polymer processing technologies including thermoplastic foaming such as foam injection molding. At present, no detailed data is available concerning the foam injection molding behavior and foam properties of Bio-PC. This contribution provides first results on injection-molded foams based on isosorbide-containing PC. The s...

  13. Study of Thermal Properties of Cast Metal- Ceramic Composite Foams

    OpenAIRE

    Gawdzińska K.; Chybowski L.; Przetakiewicz W.

    2017-01-01

    Owing to its properties, metallic foams can be used as insulation material. Thermal properties of cast metal-ceramic composite foams have applications in transport vehicles and can act as fire resistant and acoustic insulators of bulkheads. This paper presents basic thermal properties of cast and foamed aluminum, the values of thermal conductivity coefficient of selected gases used in foaming composites and thermal capabilities of composite foams (AlSi11/SiC). A certificate of non-combustibil...

  14. Stress wave propagation and mitigation in two polymeric foams

    Science.gov (United States)

    Pradel, Pierre; Malaise, Frederic; Cadilhon, Baptiste; Quessada, Jean-Hugues; de Resseguier, Thibaut; Delhomme, Catherine; Le Blanc, Gael

    2017-06-01

    Polymeric foams are widely used in industry for thermal insulation or shock mitigation. This paper investigates the ability of a syntactic epoxy foam and an expanded polyurethane foam to mitigate intense (several GPa) and short duration (buckling of the matrix and damage of the structure. In the epoxy foam, the compaction is due to the crushing of glass microspheres. Two porous material models successfully represent the macroscopic response of these polymeric foams.

  15. Extraction kinetics of uranium (VI) with polyurethane foam

    International Nuclear Information System (INIS)

    Huang, Ting-Chia; Chen, Dong-Hwang; Huang, Shius-Dong; Huang, Ching-Tsven; Shieh, Mu-Chang.

    1993-01-01

    The extraction kinetics of uranium(VI) from aqueous nitrate solution with polyether-based polyurethane foam was investigated in a batch reactor with automatic squeezing. The extraction curves of uranium(VI) concentration in solution vs. extraction time exhibited a rather rapid exponential decay within the first few minutes, followed by a slower exponential decay during the remaining period. This phenomenon can be attributed to the presence of two-phase structure, hard segment domains and soft segment matrix in the polyurethane foam. A two-stage rate model expressed by a superposition of two exponential curves was proposed, according to which the experimental data were fitted by an optimization method. The extraction rate of uranium (VI) was also found to increase with increasing temperature, nitrate concentration, and hydration of the cation of nitrate salt. (author)

  16. A Method to Produce Foam Glasses

    DEFF Research Database (Denmark)

    2016-01-01

    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......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...

  17. Auxetic foam for snowsport safety devices

    OpenAIRE

    Allen, Tom; Duncan, Olly; Foster, Leon; Senior, Terry; Zampieri, Davide; Edeh, Victor; Alderson, Andrew

    2017-01-01

    Skiing and snowboarding are popular snow-sports with inherent risk of injury. There is potential to reduce the prevalence of injuries by improving and implementing snow-sport safety devices with the application of advanced materials. This paper investigates the application of auxetic foam to snow-sport safety devices. Composite pads - consisting of foam covered with a semi-rigid shell - were investigated as a simple model of body armour and a large 70 x 355 x 355 mm auxetic foam sample was fa...

  18. 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

  19. Foam process for application of decontamination agents

    International Nuclear Information System (INIS)

    Harris, J.M.; Miller, J.R.; Frazier, R.S.; Walter, J.H.

    1982-01-01

    This paper presents the results and observations of a study performed by the authors to parametrically evaluate the performance characteristics of a foam process for application of decontamination agents. The initial tests were established to assess foam quality. Subsequent tests determined the ability of the foam as a carrier of chemical systems, and established system operating parameters. The technique was then applied in an actual decontamination task to verify effectiveness of these established parameters and to determine decontamination reduction factors. 4 figures, 5 tables

  20. A Novel Foam Contrast Agent Suitable for Fluoroscopic Interventional Procedure: Comparative Study of Physical Properties and Experimental Intervention in Animal Model

    Directory of Open Access Journals (Sweden)

    Jin Ho Hwang

    2015-01-01

    Full Text Available In fluoroscopic contrast study for interventional procedure, liquid contrast agent may be diluted in body fluid, losing its contrast effect. We developed a novel contrast agent of “foam state” to maintain contrast effect for enough time and performed a comparative study of physical properties and its usefulness in experimental intervention in animal model. The mean size of microbubble of foam contrast was 13.8±3.6 µm. The viscosity was 201.0±0.624 cP (centipoise and the specific gravity was 0.616. The foam decayed slowly and it had 97.5 minutes of half-life. In terms of the sustainability in a slow flow environment, foam contrast washed out much more slowly than a conventional contrast. In experimental colonic stent placement, foam contrast revealed significantly better results than conventional contrast in procedure time, total amount of contrast usage, and the number of injections (p<0.05. Our foam contrast has high viscosity and low specific gravity and maintains foam state for a sufficient time. Foam contrast with these properties was useful in experimental intervention in animal model. We anticipate that foam contrast may be applied to various kinds of interventional procedures.

  1. Research on Gas-liquid Flow Rate Optimization in Foam Drilling

    Science.gov (United States)

    Gao, B. K.; Sun, D. G.; Jia, Z. G.; Huang, Z. Q.

    2010-03-01

    With the advantages of less gas consumption, higher carrying rocks ability, lower leakage and higher penetration rate, foam drilling is widely used today in petroleum industry. In the process of foam underbalanced drilling, the mixture of gas, liquid and cuttings flows upwards through the annular, so it is a typical gas-liquid-solid multi-phase flow. In order to protect the reservoir and avoid borehole wall collapsing during foam drilling, it is crucial to ensure that the bottom hole pressure is lower than the formation pressure and higher than the formation collapse pressure, and in the mean time, foam drilling fluid in the whole wellbore should be in the best foam quality stage in order to have sufficient capacity to carry cuttings. In this paper, main relations between bottom hole pressure and gas-liquid injecting rate are analyzed with the underbalanced multiphase flow models. And in order to obtain precise flow pattern and flow pressure, the whole well bore is spatial meshed and iterative method is used. So, a convenient safety window expressed by gas-liquid injecting rate is obtained instead of that by bottom hole pressure. Finally, a foam drilling example from a block in Yemen is presented; the drilling results show that this method is reliable and practical.

  2. Damage Analysis of Aluminium Foam Panel Subjected to Underwater Shock Loading

    Directory of Open Access Journals (Sweden)

    Xuan He

    2017-01-01

    Full Text Available Underwater shock loading experiment device is the equipment which simulates underwater explosive shock wave through experiment. Underwater shock loading experiment device was used to conduct high-speed underwater impact on aluminium foam panel and its damage modes were studied in this paper. 3D dynamic DIC test system was used to collect and analyze real-time deformation of target board. After the experiment was completed, a numerical simulation of the series of experiment was conducted through ABAQUS finite element simulation and then a comparative analysis of the experiment was implemented. To comprehensively study damage modes of aluminium foam panel subjected to underwater shock loading, damage modes of aluminium foam panel at different shock speeds were studied. Results indicated that when a certain impact speed which could damage aluminium foam panel was reached, if the impact speed was low, aluminium foam panel would generate shear fracture at constrained boundary of flange; if the impact speed was high, aluminium foam panel would firstly generate fracture at the center and then generate shear fracture at constrained boundary of flange, and central fracture would generate three cracks.

  3. Shear Modulus for Nonisotropic, Open-Celled Foams Using a General Elongated Kelvin Foam Model

    Science.gov (United States)

    Sullivan, Roy M.; Ghosn, Louis J.

    2008-01-01

    An equation for the shear modulus for nonisotropic, open-celled foams in the plane transverse to the elongation (rise) direction is derived using an elongated Kelvin foam model with the most general geometric description. The shear modulus was found to be a function of the unit cell dimensions, the solid material properties, and the cell edge cross-section properties. The shear modulus equation reduces to the relation derived by others for isotropic foams when the unit cell is equiaxed.

  4. Precedent Proper Names in Informal Oikonymy

    Directory of Open Access Journals (Sweden)

    Maria V. Akhmetova

    2013-06-01

    Full Text Available The paper deals with the Russian language informal city names (oikonyms motivated by other toponyms (with reference to Russia and the CIS. The author shows that the motivating proper name can replace the city name (e. g. Глазго < Glasgow ‘Glazov’ or contaminate with it (e. g. Экибостон < Ekibastuz + Boston, the “alien” onym being attracted to construct an informal oikonym due to its phonetic similarity or, on occasion, due to an affinity, either real or imaginary, between the two settlements. The author argues that the phonetic motivation is more characteristic for the modern urban tradition, than for popular dialects.

  5. Sodium borohydride hydrogen generator using Co–P/Ni foam catalysts for 200 W proton exchange membrane fuel cell system

    International Nuclear Information System (INIS)

    Oh, Taek Hyun; Gang, Byeong Gyu; Kim, Hyuntak; Kwon, Sejin

    2015-01-01

    The response characteristics of electroless-deposited Co–P/Ni foam catalysts for sodium borohydride hydrolysis were investigated. The effect of nickel foam geometry on the properties of the catalysts was evaluated. As the PPI (pores per inch) of the nickel foam increased, the hydrogen generation rate per gram of the deposited catalyst increased due to an increase in surface area. The response characteristics of various catalysts were compared under real operating conditions. When a thin nickel foam with high PPI was used, the response characteristics of the catalyst improved due to an increase in the amount of the deposited catalyst and surface area. Finally, a 200 W PEMFC (proton exchange membrane fuel cell) system using electroless-deposited Co–P/Ni foam (110 PPI) catalyst was investigated. The response time to reach a hydrogen generation rate sufficient for a 200 W PEMFC was 71 s, and the energy density of a 200 W fuel cell system for producing 600 Wh was 252.1 Wh/kg. A fuel cell system using Co–P/Ni foam catalysts can be widely used as a power source for mobile applications due to fast response characteristics and high energy density. - Highlights: • Response characteristics of Co–P/Ni foam catalysts are investigated. • Catalytic activity is improved with increase in PPI (pores per inch) of Ni foam. • Co–P/Ni foam (110 PPI) catalyst has improved response characteristics. • The energy density of a 200 W PEMFC system for producing 600 Wh is 252.1 Wh/kg. • Co–P/Ni foam (110 PPI) catalyst is suitable for fuel cell system.

  6. Fire Behavior of Rigid Polyurethane Foam and Metal Faced Polyurethane Sandwich Panels and Its Fire Hazard Assessment

    Directory of Open Access Journals (Sweden)

    S. Bakhtiyari

    2009-12-01

    Full Text Available Reaction to fire of fire-retarded rigid PUR foams and two types of metal faced rigid polyurethane foam core sandwich panel was evaluated by using cone calorimeter test method. The tests were carried out in various radiative heat fluxes from 15 to 75 kW/m2. The radiation rate effect on reaction to fire parameters, including time to ignition (TTI, peak of heat release rate (PRHR, total heat release (THR, average heat release rate (Av.RHR and average heat of combustion (Av.EHC was investigated. The phenomenon of char forming, when the foam is exposed to heat, leads to the formation of a protective layer on the surface of foam and hence no direct relation exists between Av.RHR and average specific mass loss rate (Av.Spec.MLR of foam with increased radiation rate. In addition, the increased PRHR with foam density was also very smooth. The relation between TTI and heat flux was investigated for the foam and its corresponding correlation has been achieved with a specified density. Fire hazard assessment of foams and sandwitch panels was carried out by adopting Petrella and Richardson fire risk classification methods. The assessment results showed that rigid PUR foam and PUR sandwich panels may have a high contribution to bring the room to critical flashover condition, but the risk is intermediate from the viewpoint of fire endurance. The reasons of these risk levels are attributed to a very short TTI, relative high PRHR and an intermediate amount of THR. Decrease in foam density reduces heat release but it shows no significant effect on reducing flashover hazard.

  7. Investigation on stabilization of CO2 foam by ionic and nonionic surfactants in presence of different additives for application in enhanced oil recovery

    Science.gov (United States)

    Kumar, Sunil; Mandal, Ajay

    2017-10-01

    Application of foam in upstream petroleum industry specifically in enhanced oil recovery (EOR) has gained significant interest in recent years. In view of this, an attempt has been paid to design the suitable foaming agents (foamer) by evaluating the influence of three surfactants, five nanoparticles and several additives. Experimental investigations have been carried out in order to examine the mechanism of foam generation in presence of sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB) and polysorbate 80 (Tween 80) as anionic, cationic and nonionic surfactants by using the CO2 as gaseous component. It has been found that ionic surfactants show the higher foam life compared to nonionic surfactant. Out of different nano particles used, namely alumina (Al2O3) zirconium oxide (ZrO2), calcium carbonate (CaCO3), boron nitride (BN) and silica (SiO2), boron nitride shows the maximum improvement of foam stability. The foam stability of surfactant-nanoparticles foam is further increased by addition of different additives viz. polymer, alcohol and alkali. The results show that, the designed foaming solution have nearly 2.5 times higher half-decay time (t1/2) compared to the simple surfactant system. Finally, it has been found that gas injection rate plays an important role in obtaining a uniform and stabilized foam.

  8. The foamed structures in numerical testing

    Science.gov (United States)

    John, Antoni; John, Małgorzata

    2018-01-01

    In the paper numerical simulation of the foamed metal structures using numerical homogenization algorithm is prescribed. From the beginning, numerical model of heterogeneous porous simplified structures of typical foamed metal, based on the FEM was built and material parameters (coefficients of elasticity matrix of the considered structure) were determined with use of numerical homogenization algorithm. During the work the different RVE models of structure were created and their properties were compared at different relative density, different numbers and the size and structure of the arrangement of voids. Finally, obtained results were used in modeling of typical elements made from foam metals structures - sandwich structure and profile filled with metal foam. Simulation were performed for different dimensions of cladding and core. Additionally, the test of influence material orientation (arrangement of voids in RVE element) on the maximum stresses and displacement during bending test was performed.

  9. Coated foams, preparation, uses and articles

    Science.gov (United States)

    Duchane, D.V.; Barthell, B.L.

    1982-10-21

    Hydrophobic cellular material is coated with a thin hydrophilic polymer skin which stretches tightly over the foam but which does not fill the cells of the foam, thus resulting in a polymer-coated foam structure having a smoothness which was not possible in the prior art. In particular, when the hydrophobic cellular material is a specially chosen hydrophobic polymer foam and is formed into arbitrarily chosen shapes prior to the coating with hydrophilic polymer, inertial confinement fusion (ICF) targets of arbitrary shapes can be produced by subsequently coating the shapes with metal or with any other suitable material. New articles of manufacture are produced, including improved ICF targets, improved integrated circuits, and improved solar reflectors and solar collectors. In the coating method, the cell size of the hydrophobic cellular material, the viscosity of the polymer solution used to coat, and the surface tension of the polymer solution used to coat are all very important to the coating.

  10. Modeling Decomposition of Unconfined Rigid Polyurethane Foam

    National Research Council Canada - National Science Library

    Hobbs, Michael

    1999-01-01

    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...

  11. 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

  12. Numerical study of metal foam heat sinks under uniform impinging flow

    International Nuclear Information System (INIS)

    Andreozzi, A; Bianco, N; Iasiello, M; Naso, V

    2017-01-01

    The ever-increasing demand for performance improvement and miniaturization of electronics has led to a significant generation of waste heat that must be dissipated to ensure a reliable device operation. The miniaturization of the components complicates this task. In fact, reducing the heat transfer area, at the same required heat rate, it is necessary to increase the heat flux, so that the materials operate in a temperature range suitable to its proper functioning. Traditional heat sinks are no longer capable of dissipating the generated heat and innovative approaches are needed to address the emerging thermal management challenges. Recently, heat transfer in open-cell metal foams under an impinging jet has received attention due to the considerable heat transfer potential of combining two cooling technologies: impinging jet and porous medium. This paper presents a numerical study on Finned Metal Foam (FMF) and Metal Foam (MF) heat sinks under impinging air jet cooling. The analysis is carried out by means of the commercial software COMSOL Multiphysics®. The purpose is to analyze the thermal performance of the metal foam heat sink, finned or not, varying its geometric parameters. Results are presented in terms of predicted dissipated heat rate, convective heat transfer coefficient and pressure losses. (paper)

  13. Numerical study of metal foam heat sinks under uniform impinging flow

    Science.gov (United States)

    Andreozzi, A.; Bianco, N.; Iasiello, M.; Naso, V.

    2017-01-01

    The ever-increasing demand for performance improvement and miniaturization of electronics has led to a significant generation of waste heat that must be dissipated to ensure a reliable device operation. The miniaturization of the components complicates this task. In fact, reducing the heat transfer area, at the same required heat rate, it is necessary to increase the heat flux, so that the materials operate in a temperature range suitable to its proper functioning. Traditional heat sinks are no longer capable of dissipating the generated heat and innovative approaches are needed to address the emerging thermal management challenges. Recently, heat transfer in open-cell metal foams under an impinging jet has received attention due to the considerable heat transfer potential of combining two cooling technologies: impinging jet and porous medium. This paper presents a numerical study on Finned Metal Foam (FMF) and Metal Foam (MF) heat sinks under impinging air jet cooling. The analysis is carried out by means of the commercial software COMSOL Multiphysics®. The purpose is to analyze the thermal performance of the metal foam heat sink, finned or not, varying its geometric parameters. Results are presented in terms of predicted dissipated heat rate, convective heat transfer coefficient and pressure losses.

  14. Bio-Based Polyols from Seed Oils for Water-Blown Rigid Polyurethane Foam Preparation

    Directory of Open Access Journals (Sweden)

    Paweena Ekkaphan

    2016-01-01

    Full Text Available The preparation of water-blown rigid polyurethane (RPUR foams using bio-based polyols from sesame seed oil and pumpkin seed oil has been reported. Polyols synthesis involved two steps, namely, hydroxylation and alcoholysis reaction. FTIR, NMR, and ESI-MS were used to monitor the process of the synthesized polyols and their physicochemical properties were determined. The resulting polyols have OH number in the range of 340–351 mg KOH/g. RPUR foams blown with water were produced from the reaction of biopolyols with commercial polymeric methylene diphenyl diisocyanate (PMDI. The proper PUR formulations can be manipulated to produce the desired material applications. These seed oil-based RPUR foams exhibited relatively high compressive strength (237.7–240.2 kPa with the density in the range of 40–45 kg/m3. Additionally, the cell foam morphology investigated by scanning electron microscope indicated that their cellular structure presented mostly polygonal closed cells. The experimental results demonstrate that these bio-based polyols can be used as an alternative starting material for RPUR production.

  15. RANS Simulations using OpenFOAM Software

    Science.gov (United States)

    2016-01-01

    the potential to perform large scale CFD simulations without incurring the significant licence fees concomitant with using commercial software ...UNCLASSIFIED UNCLASSIFIED RANS Simulations using OpenFOAM Software D.A. Jones1, M. Chapuis3, M. Liefvendahl3, D. Norrison1, and R. Widjaja2...Agency - FOI, SE 147 25 Tumba, Stockholm, Sweden DST-Group-TR-3204 ABSTRACT The use of the OpenFOAM software suite for the performance of Reynolds

  16. Measurement of radiant properties of ceramic foam

    International Nuclear Information System (INIS)

    Hoornstra, J.; Turecky, M.; Maatman, D.

    1994-07-01

    An experimental facility is described for the measurement of the normal spectral and total emissivity and transmissivity of semi-transparent materials in the temperature range of 600 C to 1200 C. The set-up was used for the measurement of radiation properties of highly porous ceramic foam which is used in low NO x radiant burners. Emissivity and transmissivity data were measured and are presented for coated and uncoated ceramic foam of different thicknesses. (orig.)

  17. Unusual properties of foams at low pressures.

    Science.gov (United States)

    Fortes, M A; Vaz, M Fátima

    2003-10-01

    In addition to a high coarsening rate, foams at low pressures may show special properties. These include a bulk modulus going to zero, a Poisson's ratio approaching zero, and a zero binding energy, implying foam separation into individual bubbles at a critical pressure. We provide examples of calculations made for particular two-dimensional clusters with an ideal gas, which illustrate these features. We also discuss the difficulties in performing experiments at the low pressures at which the unusual properties show up.

  18. Sound absorption property of openpore aluminum foams

    OpenAIRE

    WANG Fang; WANG Lu-cai; WU Jian-guo

    2007-01-01

    This paper presents a study on sound absorption property of aluminum foam by evaluating its sound absorption coefficients using standing wave tube method. Experimental results showed that the average values of sound absorption coefficients (over the test frequency range) are all above 0.4, which indicate very good sound absorption property of the aluminum foams. The sound absorption coefficient is affected by frequency and pore structure, and reaches its maximum value at around 1 000 Hz. With...

  19. New supply for canyon fire foam system

    International Nuclear Information System (INIS)

    Gainey, T.

    1995-01-01

    The raw water supply for the B-Plant Canyon fire foam system is being replaced. The 4 inche water supply line to the foam system is being rerouted from the 6 inches raw water line in the Pipe Gallery to the 10 inches raw water main in the Operating Gallery. This document states the acceptance criteria for the flushing and testing to be performed by the contractor

  20. Foam Rolling for Delayed-Onset Muscle Soreness and Recovery of Dynamic Performance Measures

    Science.gov (United States)

    Pearcey, Gregory E. P.; Bradbury-Squires, David J.; Kawamoto, Jon-Erik; Drinkwater, Eric J.; Behm, David G.; Button, Duane C.

    2015-01-01

    Context: After an intense bout of exercise, foam rolling is thought to alleviate muscle fatigue and soreness (ie, delayed-onset muscle soreness [DOMS]) and improve muscular performance. Potentially, foam rolling may be an effective therapeutic modality to reduce DOMS while enhancing the recovery of muscular performance. Objective: To examine the effects of foam rolling as a recovery tool after an intense exercise protocol through assessment of pressure-pain threshold, sprint time, change-of-direction speed, power, and dynamic strength-endurance. Design: Controlled laboratory study. Setting: University laboratory. Patients or Other Participants: A total of 8 healthy, physically active males (age = 22.1 ± 2.5 years, height = 177.0 ± 7.5 cm, mass = 88.4 ± 11.4 kg) participated. Intervention(s): Participants performed 2 conditions, separated by 4 weeks, involving 10 sets of 10 repetitions of back squats at 60% of their 1-repetition maximum, followed by either no foam rolling or 20 minutes of foam rolling immediately, 24, and 48 hours postexercise. Main Outcome Measure(s): Pressure-pain threshold, sprint speed (30-m sprint time), power (broad-jump distance), change-of-direction speed (T-test), and dynamic strength-endurance. Results: Foam rolling substantially improved quadriceps muscle tenderness by a moderate to large amount in the days after fatigue (Cohen d range, 0.59 to 0.84). Substantial effects ranged from small to large in sprint time (Cohen d range, 0.68 to 0.77), power (Cohen d range, 0.48 to 0.87), and dynamic strength-endurance (Cohen d = 0.54). Conclusions: Foam rolling effectively reduced DOMS and associated decrements in most dynamic performance measures. PMID:25415413

  1. Foam rolling for delayed-onset muscle soreness and recovery of dynamic performance measures.

    Science.gov (United States)

    Pearcey, Gregory E P; Bradbury-Squires, David J; Kawamoto, Jon-Erik; Drinkwater, Eric J; Behm, David G; Button, Duane C

    2015-01-01

    After an intense bout of exercise, foam rolling is thought to alleviate muscle fatigue and soreness (ie, delayed-onset muscle soreness [DOMS]) and improve muscular performance. Potentially, foam rolling may be an effective therapeutic modality to reduce DOMS while enhancing the recovery of muscular performance. To examine the effects of foam rolling as a recovery tool after an intense exercise protocol through assessment of pressure-pain threshold, sprint time, change-of-direction speed, power, and dynamic strength-endurance. Controlled laboratory study. University laboratory. A total of 8 healthy, physically active males (age = 22.1 ± 2.5 years, height = 177.0 ± 7.5 cm, mass = 88.4 ± 11.4 kg) participated. Participants performed 2 conditions, separated by 4 weeks, involving 10 sets of 10 repetitions of back squats at 60% of their 1-repetition maximum, followed by either no foam rolling or 20 minutes of foam rolling immediately, 24, and 48 hours postexercise. Pressure-pain threshold, sprint speed (30-m sprint time), power (broad-jump distance), change-of-direction speed (T-test), and dynamic strength-endurance. Foam rolling substantially improved quadriceps muscle tenderness by a moderate to large amount in the days after fatigue (Cohen d range, 0.59 to 0.84). Substantial effects ranged from small to large in sprint time (Cohen d range, 0.68 to 0.77), power (Cohen d range, 0.48 to 0.87), and dynamic strength-endurance (Cohen d = 0.54). Foam rolling effectively reduced DOMS and associated decrements in most dynamic performance measures.

  2. Comparison of sound absorbing performances of copper foam and iron foam with the same parameters

    Science.gov (United States)

    Yang, X. C.; Shen, X. M.; Xu, P. J.; Zhang, X. N.; Bai, P. F.; Peng, K.; Yin, Q.; Wang, D.

    2018-01-01

    Sound absorbing performances of the copper foam and the iron foam with the same parameters were investigated by the AWA6128A detector according to standing wave method. Two modes were investigated, which included the pure metal foam mode and the combination mode with the settled thickness of metal foam. In order to legibly compare the sound absorbing coefficients of the two metal foams, the detected sound frequency points were divided into the low frequency range (100 Hz ~ 1000 Hz), the middle frequency range (1000 Hz ~ 3200 Hz), and the high frequency range (3500 Hz ~ 6000 Hz). Sound absorbing performances of the two metal foams in the two modes were discussed within the three frequency ranges in detail. It would be calculated that the average sound absorbing coefficients of copper foam in the pure metal foam mode were 12.6%, 22.7%, 34.6%, 43.6%, 51.1%, and 56.2% when the thickness was 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, and 30 mm. meanwhile, in the combination mode, the average sound absorbing coefficients of copper foam with the thickness of 10 mm were 30.6%, 34.8%, 36.3%, and 35.8% when the cavity was 5 mm, 10 mm, 15 mm, and 20 mm. In addition, those of iron foam in the pure metal foam mode were 13.4%, 20.1%, 34.4%, 43.1%, 49.6%, and 56.1%, and in the combination mode were 25.6%, 30.5%, 34.3%, and 33.4%.

  3. Nano-Composite Foam Sensor System in Football Helmets.

    Science.gov (United States)

    Merrell, A Jake; Christensen, William F; Seeley, Matthew K; Bowden, Anton E; Fullwood, David T

    2017-12-01

    American football has both the highest rate of concussion incidences as well as the highest number of concussions of all contact sports due to both the number of athletes and nature of the sport. Recent research has linked concussions with long term health complications such as chronic traumatic encephalopathy and early onset Alzheimer's. Understanding the mechanical characteristics of concussive impacts is critical to help protect athletes from these debilitating diseases and is now possible using helmet-based sensor systems. To date, real time on-field measurement of head impacts has been almost exclusively measured by devices that rely on accelerometers or gyroscopes attached to the player's helmet, or embedded in a mouth guard. These systems monitor motion of the head or helmet, but do not directly measure impact energy. This paper evaluates the accuracy of a novel, multifunctional foam-based sensor that replaces a portion of the helmet foam to measure impact. All modified helmets were tested using a National Operating Committee Standards for Athletic Equipment-style drop tower with a total of 24 drop tests (4 locations with 6 impact energies). The impacts were evaluated using a headform, instrumented with a tri-axial accelerometer, mounted to a Hybrid III neck assembly. The resultant accelerations were evaluated for both the peak acceleration and the severity indices. These data were then compared to the voltage response from multiple Nano Composite Foam sensors located throughout the helmet. The foam sensor system proved to be accurate in measuring both the HIC and Gadd severity index, as well as peak acceleration while also providing additional details that were previously difficult to obtain, such as impact energy.

  4. Refractory Ceramic Foams for Novel Applications

    Science.gov (United States)

    Stackpoole, M.

    2008-01-01

    Workers at NASA Ames Research center are endeavoring to develop durable, oxidation-resistant, foam thermal protection systems (TPSs) that would be suitable for covering large exterior spacecraft surfaces, would have low to moderate densities, and would have temperature capabilities comparable to those of carbon-based TPSs [reusable at 3,000 F (.1,650 C)] with application of suitable coatings. These foams may also be useful for repairing TPSs while in orbit. Moreover, on Earth as well as in outer space, these foams might be useful as catalyst supports and filters. Preceramic polymers are obvious candidates for use in making the foams in question. The use of these polymers offers advantages over processing routes followed in making conventional ceramics. Among the advantages are the ability to plastically form parts, the ability to form pyrolized ceramic materials at lower temperatures, and the ability to form high-purity microstructures having properties that can be tailored to satisfy requirements. Heretofore, preceramic polymers have been used mostly in the production of such low-dimensional products as fibers because the loss of volatiles during pyrolysis of the polymers leads to porosity and large shrinkage (in excess of 30 percent). In addition, efforts to form bulk structures from preceramic polymers have resulted in severe cracking during pyrolysis. However, because the foams in question would consist of networks of thin struts (in contradistinction to nonporous dense solids), these foams are ideal candidates for processing along a preceramic-polymer route.

  5. 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.

  6. Securing radioactive sources through a proper management

    Energy Technology Data Exchange (ETDEWEB)

    Mourao, Rogerio Pimenta [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Gerencia de Rejeitos], e-mail: mouraor@cdtn.br

    2009-07-01

    The safety and security of radioactive sources have become a hot issue for the nuclear community in the last two decades. The Goiania accident in Brazil and the September 11th attack alerted governments and nuclear agencies around the world to the vulnerability of the thousands of disused radioactive sources ill-stored or misplaced in a myriad of ways, especially in countries with less developed infra-structure. Once the threat of environmental contamination or malevolent use of these sources became clear, the International Atomic Energy Agency and the American Government spawned initiatives to reduce this risk, basically stimulating the proper conditioning of the sources and, whenever possible, seeking their repatriation to the countries of origin. Since 1996 Brazil has been participating actively in this effort, having carried out hands-on operations to condition old radium sources in Latin American and Caribbean countries and also repatriated its own neutron sources to the United States. A new operation is presently being organized: the reconditioning of the high activity sources contained in teletherapy units stored in the country using a mobile hot cell developed in South Africa. Also an agreement is being negotiated between the US National Nuclear Security Agency and the Brazilian CNEN to repatriate hundreds of radioactive gauges presently stored at CNEN's source storage buildings. (author)

  7. Securing radioactive sources through a proper management

    International Nuclear Information System (INIS)

    Mourao, Rogerio Pimenta

    2009-01-01

    The safety and security of radioactive sources have become a hot issue for the nuclear community in the last two decades. The Goiania accident in Brazil and the September 11th attack alerted governments and nuclear agencies around the world to the vulnerability of the thousands of disused radioactive sources ill-stored or misplaced in a myriad of ways, especially in countries with less developed infra-structure. Once the threat of environmental contamination or malevolent use of these sources became clear, the International Atomic Energy Agency and the American Government spawned initiatives to reduce this risk, basically stimulating the proper conditioning of the sources and, whenever possible, seeking their repatriation to the countries of origin. Since 1996 Brazil has been participating actively in this effort, having carried out hands-on operations to condition old radium sources in Latin American and Caribbean countries and also repatriated its own neutron sources to the United States. A new operation is presently being organized: the reconditioning of the high activity sources contained in teletherapy units stored in the country using a mobile hot cell developed in South Africa. Also an agreement is being negotiated between the US National Nuclear Security Agency and the Brazilian CNEN to repatriate hundreds of radioactive gauges presently stored at CNEN's source storage buildings. (author)

  8. Pretransformation strain modulations in proper ferroelastics

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, A. (Los Alamos National Lab., NM (United States)); Barsch, G.R. (Pennsylvania State Univ., University Park, PA (United States))

    1992-01-01

    Within the framework of the Landau-Ginzburg model for the 0[sub h]-D[sub 4h] proper ferroelastic transformation pretransformation structural modulations may arise as (possibly defect-stabilized) pseudo-critical fluctuations that can be described by an effective elastic [phi][sub 4] model. Here we show that the strain amplitude and temperature dependence of an intermediate tetragonal phase observed above and concurrently with the face-centered cubic to face-centered tetragonal transition in Fe[sub 0.7]Pd[sub 0.3] can be understood semi-quantitatively in terms of the crossover behavior from the Ising to the displacive limit by applying the crossover phase diagram of Beale, Sarker and Krumhanal to the effective [phi][sup 4] model. The fact that this type of pretransformation modulation has not been observed with X-ray for other ferroelastic transformations can be attributed to large values of the order parameter gradient coefficient in these cases.

  9. Pretransformation strain modulations in proper ferroelastics

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, A. [Los Alamos National Lab., NM (United States); Barsch, G.R. [Pennsylvania State Univ., University Park, PA (United States)

    1992-12-31

    Within the framework of the Landau-Ginzburg model for the 0{sub h}-D{sub 4h} proper ferroelastic transformation pretransformation structural modulations may arise as (possibly defect-stabilized) pseudo-critical fluctuations that can be described by an effective elastic {phi}{sub 4} model. Here we show that the strain amplitude and temperature dependence of an intermediate tetragonal phase observed above and concurrently with the face-centered cubic to face-centered tetragonal transition in Fe{sub 0.7}Pd{sub 0.3} can be understood semi-quantitatively in terms of the crossover behavior from the Ising to the displacive limit by applying the crossover phase diagram of Beale, Sarker and Krumhanal to the effective {phi}{sup 4} model. The fact that this type of pretransformation modulation has not been observed with X-ray for other ferroelastic transformations can be attributed to large values of the order parameter gradient coefficient in these cases.

  10. Preparation of highly stable zeolite-alginate foam composite for strontium(90Sr) removal from seawater and evaluation of Sr adsorption performance.

    Science.gov (United States)

    Hong, Hye-Jin; Kim, Byoung-Gyu; Ryu, Jungho; Park, In-Su; Chung, Kang-Sup; Lee, Sang Moon; Lee, Jin-Bae; Jeong, Hyeon Su; Kim, Hyunchul; Ryu, Taegong

    2018-01-01

    Alginate bead is a promising strontium (Sr) adsorbent in seawater, but highly concentrated Na ions caused over-swelling and damaged the hydrogel bead. To improve the mechanical stability of alginate bead, flexible foam-type zeolite-alginate composite was synthesized and Sr adsorption performance was evaluated in seawater; 1-10% zeolite immobilized alginate foams were prepared by freeze-dry technique. Immobilization of zeolite into alginate foam converted macro-pores to meso-pores which lead to more compact structure. It resulted in less swollen composite in seawater medium and exhibited highly improved mechanical stability compared with alginate bead. Besides, Sr adsorption efficiency and selectivity were enhanced by immobilization of zeolite in alginate foam due to the increase of Sr binding sites (zeolite). In particular, Sr selectivity against Na was highly improved. The 10% zeolite-alginate foam exhibited a higher log K d of 3.3, while the pure alginate foam exhibited 2.7 in the presence of 0.1 M Na. Finally, in the real seawater, the 10% zeolite-alginate foam exhibited 1.5 times higher Sr adsorption efficiency than the pure alginate foam. This result reveals that zeolite-alginate foam composite is appropriate material for Sr removal in seawater due to its swelling resistance as well as improved Sr adsorption performance in complex media. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    NARCIS (Netherlands)

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

    1990-01-01

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

  12. 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

  13. 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.

  14. Treatment of concentrated industrial wastewaters originating from oil shale and the like by electrolysis polyurethane foam interaction

    Science.gov (United States)

    Tiernan, Joan E.

    1990-01-01

    Highly concentrated and toxic petroleum-based and synthetic fuels wastewaters such as oil shale retort water are treated in a unit treatment process by electrolysis in a reactor containing oleophilic, ionized, open-celled polyurethane foams and subjected to mixing and laminar flow conditions at an average detention time of six hours. Both the polyurethane foams and the foam regenerate solution are re-used. The treatment is a cost-effective process for waste-waters which are not treatable, or are not cost-effectively treatable, by conventional process series.

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

    DEFF Research Database (Denmark)

    Kougias, Panagiotis; Tsapekos, Panagiotis; Boe, Kanokwan

    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...... 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....... 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...

  16. Editorial: The proper place for knowledge

    Directory of Open Access Journals (Sweden)

    Yngve Nordkvelle

    2009-11-01

    Full Text Available Knowledge is an interesting word, which never goes out of fashion. In the political context, knowledge is something everyone hails and cherishes. An example is that the Socialist Government in Norway renamed its "Ministry of Education and Research" to the "Ministry of Knowledge". It would probably be politically wrong to defy the word "knowledge". The word "knowledge" stirs, however, different sentiments in people. In modern education, the word signifies something notable, discernable, visual or at least possible to distinguish from what it is not. In learning in higher education, knowledge is most often considered as the raw material for learning, with the little extra that distinguishes it from "information". Knowledge is information with a direction, a purpose and meaning, but without the implied cultivation of a teaching and learning process. Given knowledge is used for educational purposes, the processing of knowledge from its basic concepts to embodied and reflected knowledge, properly understood and reconceptualised by the learner, transforms not only the learner, but also the knowledge. In a peripatetic tradition, one likes to think of knowledge as foundation elements for constructions of ethical wisdom as its highest reflective level. Probably we will never see a "Ministry of Wisdom" established, because what is "wisdom" is probably so much more politically charged than "Knowledge". One can only wonder why anyone would degrade a ministry for education to something less. In Europe a rewriting of university curricula is underway all over the continent, because "knowledge" is a key concept in the writing of "learning outcomes". It appears every college is absorbed in sorting out what knowledge is and how knowledge can be classified in categories and levels, and then composed to readable descriptions of syllabi, course descriptions and schemes. Let us hope they are more able than what has been the case. Professor Ronald Barnett of the

  17. Novel approach for extinguishing large-scale coal fires using gas-liquid foams in open pit mines.

    Science.gov (United States)

    Lu, Xinxiao; Wang, Deming; Qin, Botao; Tian, Fuchao; Shi, Guangyi; Dong, Shuaijun

    2015-12-01

    Coal fires are a serious threat to the workers' security and safe production in open pit mines. The coal fire source is hidden and innumerable, and the large-area cavity is prevalent in the coal seam after the coal burned, causing the conventional extinguishment technology difficult to work. Foams are considered as an efficient means of fire extinguishment in these large-scale workplaces. A noble foam preparation method is introduced, and an original design of cavitation jet device is proposed to add foaming agent stably. The jet cavitation occurs when the water flow rate and pressure ratio reach specified values. Through self-building foaming system, the high performance foams are produced and then infused into the blast drilling holes at a large flow. Without complicated operation, this system is found to be very suitable for extinguishing large-scale coal fires. Field application shows that foam generation adopting the proposed key technology makes a good fire extinguishment effect. The temperature reduction using foams is 6-7 times higher than water, and CO concentration is reduced from 9.43 to 0.092‰ in the drilling hole. The coal fires are controlled successfully in open pit mines, ensuring the normal production as well as the security of personnel and equipment.

  18. Role of major wine constituents in the foam properties of white and rosé sparkling wines.

    Science.gov (United States)

    Martínez-Lapuente, Leticia; Guadalupe, Zenaida; Ayestarán, Belén; Pérez-Magariño, Silvia

    2015-05-01

    The chemical composition of sparkling wines is directly related to their foam quality, but the compounds responsible are not yet completely established. This work aims at identifying the contribution of the different wine compounds to the foaming properties of white and rosé sparkling wines. Our results demonstrated the positive contribution of anthocyanins and amino acids to the foamability parameters HM (maximum height reached by foam after CO2 injection) and HS (foam stability height during CO2 injection), and the negative contribution of proanthocyanidins. Mannoproteins and polysaccharides rich in arabinose and galactose (PRAG) were poor foam formers but good foam stabilizers. The different forms of malvidin showed the highest influence on the HM and HS parameters, followed by amino acid compounds, mainly β-alanine. The model to explain foam stability was only predicted by polysaccharides from grapes, concretely PRAG. To our knowledge, this is the first time these correlations in sparkling wines have been described. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. The Laser ablation of a metal foam: The role of electron-phonon coupling and electronic heat diffusivity

    Science.gov (United States)

    Rosandi, Yudi; Grossi, Joás; Bringa, Eduardo M.; Urbassek, Herbert M.

    2018-01-01

    The incidence of energetic laser pulses on a metal foam may lead to foam ablation. The processes occurring in the foam may differ strongly from those in a bulk metal: The absorption of laser light, energy transfer to the atomic system, heat conduction, and finally, the atomistic processes—such as melting or evaporation—may be different. In addition, novel phenomena take place, such as a reorganization of the ligament network in the foam. We study all these processes in an Au foam of average porosity 79% and an average ligament diameter of 2.5 nm, using molecular dynamics simulation. The coupling of the electronic system to the atomic system is modeled by using the electron-phonon coupling, g, and the electronic heat diffusivity, κe, as model parameters, since their actual values for foams are unknown. We show that the foam coarsens under laser irradiation. While κe governs the homogeneity of the processes, g mainly determines their time scale. The final porosity reached is independent of the value of g.

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

    Science.gov (United States)

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

    2017-11-01

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

  1. Application of an Elongated Kelvin Model to Space Shuttle Foams

    Science.gov (United States)

    Sullivan, Roy M.; Ghosn, Louis J.; Lerch, Bradley A.

    2009-01-01

    The space shuttle foams are rigid closed-cell polyurethane foams. The two foams used most-extensively oil space shuttle external tank are BX-265 and NCFL4-124. Because of the foaming and rising process, the foam microstructures are elongated in the rise direction. As a result, these two foams exhibit a nonisotropic mechanical behavior. A detailed microstructural characterization of the two foams is presented. Key features of the foam cells are described and the average cell dimensions in the two foams are summarized. Experimental studies are also conducted to measure the room temperature mechanical response of the two foams in the two principal material directions (parallel to the rise and perpendicular to the rise). The measured elastic modulus, proportional limit stress, ultimate tensile strength, and Poisson's ratios are reported. The generalized elongated Kelvin foam model previously developed by the authors is reviewed and the equations which result from this model are summarized. Using the measured microstructural dimensions and the measured stiffness ratio, the foam tensile strength ratio and Poisson's ratios are predicted for both foams and are compared with the experimental data. The predicted tensile strength ratio is in close agreement with the measured strength ratio for both BX-265 and NCFI24-124. The comparison between the predicted Poisson's ratios and the measured values is not as favorable.

  2. Evaluation of an antimicrobial silver foam dressing.

    Science.gov (United States)

    Park, Jun Kyu; Lee, Jong Hoon; Kwak, Jeong Ja; Shin, Hee Bong; Jung, Hae Won; Bae, Sang Won; Yeo, Eui Dong; Lee, Young Koo; Yang, Seong Seok

    2013-06-01

    CuraVAC Ag, a product that delivers negative pressure wound therapy through a polyurethane foam dressing, contains silver nanoparticles, which, when moistened with water, release silver ions onto a wound surface. The in vitro antimicrobial action of silver can destroy both gram-positive and gram-negative bacteria, as well as methicillin-resistant Staphylococcus aureus (MRSA). The purpose of this study was to assess the efficacy and in vivo outcomes of using the product. Thirty-six female Sprague-Dawley white rats, 8-weeks old and 250 g - 300 g in weight, were used. The experimental product was prepared using a vacuum-assisted closure (VAC) kit and coating it using the silver nanoparticles. For the control group, a 10% povidone-iodine solution was applied. All groups showed decreases in wound area over time, in the order CuraVAC Ag (group A) > CuraVAC (group B) > control (group C). On the third, fifth, and seventh days, wound healing efficacy scores increased in both group A and group C. Groups A and B showed more rapid decreases than group C in bacterial culture from wounds. CuraVAC Ag may be useful for treatment of wounds infected with bacteria..

  3. Three Dimensional Carbon-Bubble Foams with Hierarchical Pores for Ultra-long Cycling Life Supercapacitors.

    Science.gov (United States)

    Wang, Bowen; Zhang, Weigang; Wang, Lei; Wei, Jiake; Bai, XueDong; Liu, Jingyue; Zhang, Guanhua; Duan, Huigao

    2018-04-17

    Design and synthesis of integrated, interconnected porous structures are critical to the development of high-performance supercapacitors. We develop a novel and facial synthesis technic to construct three-dimensional carbon-bubble foams with hierarchical pores geometry. The carbon-bubble foams are fabricated by conformally coating, via catalytic decomposition of ethanol, a layer of carbon coating onto the surfaces of pre-formed ZnO foams and then the removal of the ZnO template by a reduction-evaporation process. Both the wall thickness and the pore size can be well tuned by adjusting the catalytic decomposition time and temperature. The as-synthesized carbon-bubble foams electrode retains 90.3% of the initial capacitance even after 70000 continuous cycles under a high current density of 20 A g-1, demonstrating excellent long-time electrochemical and cycling stability. The symmetric device displays rate capability retention of 81.8% with the current density increasing from 0.4 to 20 A g-1. These achieved electrochemical performances originate from the unique structural design of the carbon-bubble foams, which provide not only abundant transport channels for electron and ion but also high active surface area accessible by the electrolyte ions. © 2018 IOP Publishing Ltd.

  4. Removing a tick: proper technique in children

    Directory of Open Access Journals (Sweden)

    Susana Rueda Pérez

    2012-06-01

    Full Text Available There is medical consensus on the need to remove the tick within 24 hours the mite parasites to the human host, to avoid possible complications. The preferred way is by gently traction the mite, aided by forceps without twisting or chokes with toxic agents, because of the possibility that the mite excretes bacteria mixed with substances. The average time of extraction is estimated between one or three minutes. In children parasitized by ticks this amount of time can be excessive when it’s necessary restraint without the consent of the minor. Using this technique we reduce the time to seconds and the damage caused to the skin is minimal.

  5. Fabrication of Foam Shells for ICF Experiments

    Science.gov (United States)

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

    2004-11-01

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

  6. Thermogravimetry analysis on fused borosilicate syntactic foams

    Science.gov (United States)

    Salleh, Zulzamri; Islam, Md Mainul; Epaarachchi, Jayantha Ananda

    2017-12-01

    Fused borosilicate/vinyl ester syntactic foams mostly used for thermal stability in many applications are considered to be characterised for their properties in higher temperature condition. Therefore, higher temperature characteristics need to be explored with respect to physical parameters such as porosity and void content. The filler, also known as glass microballoons, was incorporated in vinyl ester resin matrix in 2wt%, 4wt%, 6wt.%, 8wt.% and 10wt.%. These composites are characterised and degraded to examine the onset temperature, Tonset, peak temperature, Tpeak and end temperature, Tend using thermogravimetric analysis (TGA) method. The results for Tonset showed an increment while Tend and Tpeak showed decrement when glass microballoons were added in syntactic foams. Based on TGA data, they exhibited excellent thermal stability, showing 5% weight loss at 380-450 °C. Glass transition temperature (Tg) decreased when more glass microballoons were added, and also related to the effect on the physical properties of syntactic foams. Therefore, understanding of the relationship between thermal properties of syntactic foams and their physical properties such as porosity and void content will help in developing syntactic foams to optimise their thermal characteristics, which will be beneficial for engineering applications.

  7. 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 ad...... calorimetric data show that panel glass possesses good stability against crystallisation. X-ray diffraction data show that the foaming agents enhance the surface crystallisation of the panel glass. We find that the crystallisation impedes the formation of low density foam glass.......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...

  8. 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...

  9. 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

  10. NoFoam Unit Installation, Evaluation and Operations Manual

    National Research Council Canada - National Science Library

    Fischer, William

    2003-01-01

    .... Currently, the majority of Fire Departments that use 3% Aqueous Film Forming Foam (AFFF) liquid concentrate in their fleet do not have the facilities available to conduct annual foam proportioning testing of their vehicles...

  11. Design and evaluation of foamed asphalt base materials : [research summary].

    Science.gov (United States)

    2013-05-01

    Foamed asphalt stabilized base (FASB) combines reclaimed asphalt pavement (RAP), : recycled concrete (RC), and/or graded aggregate base (GAB) with a foamed asphalt : binder to produce a partially stabilized base material. Although widely used, most :...

  12. 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.

  13. Design and evaluation of foamed asphalt base materials.

    Science.gov (United States)

    2013-05-01

    Foamed asphalt stabilized base (FASB) combines reclaimed asphalt pavement (RAP), recycled : concrete (RC), and/or graded aggregate base (GAB) with a foamed asphalt binder to produce a : partially stabilized base material. The objectives of this study...

  14. Production and Compressive Characterization of Aluminium MMC Foam Manufactured Using Dual Foaming Agent

    Science.gov (United States)

    Haidar, S.; Ansary, S.; Rahman, A.

    2016-02-01

    Aluminium foams, produced by melting Aluminium alloy (LM6) containing blowing agent(s) and vigorous stirring. TiH2 is a known agent for this. As TiH2 begins to decompose into Ti and gaseous H2 when heated above about 465°C, large volumes of hydrogen gas are rapidly produced, creating bubbles that leads to a closed cell foam. A novel Strategy to enhance the mechanical properties of Al-MMC foams is discussed here, and it is demonstrated that titanium hydride (TiH2) in the form of 10-15 μm diameter particles can be pre-treated by selective oxidation to produce more uniform foams having better compressive properties (yield strength and energy absorption). It is found that the mechanical properties of the foams and the uniformity of cell size distribution is improved when the foam is blown with an optimized mixture of CaCO3 and pretreated TiH2. In order to define the relationship of mechanical properties with relative density of this material, correlations which uniquely defines the compressive behaviour of this modified Al- MMC foam has been developed.

  15. Effectiveness of Flame Retardants in TufFoam.

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-12-01

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

  16. Structure-property relationships of flexible polyurethane foams

    Science.gov (United States)

    Aneja, Ashish

    This study examined several features of flexible polyurethane foams from a structure-property perspective. A major part of this dissertation addresses the issue of connectivity of the urea phase and its influence on mechanical and viscoelastic properties of flexible polyurethane foams and their plaque counterparts. Lithium salts (LiCl and LiBr) were used as additives to systematically alter the phase separation behavior, and hence the connectivity of the urea phase at different scale lengths. Macro connectivity, or the association of the large scale urea rich aggregates typically observed in flexible polyurethane foams was assessed using SAXS, TEM, and AFM. These techniques showed that including a lithium salt in the foam formulation suppressed the formation of the urea aggregates and thus led to a loss in the macro level connectivity of the urea phase. WAXS and FTIR were used to demonstrate that addition of LiCl or LiBr systematically disrupted the local ordering of the hard segments within the microdomains, i.e., it led to a reduction of micro level connectivity or the regularity in segmental packing of the urea phase. Based on these observations, the interaction of the lithium salt was thought to predominantly occur with the urea hard segments, and this hypothesis was confirmed using quantum mechanical calculations. Another feature of this research investigated model trisegmented polyurethanes based on monofunctional polyols, or "monos", with water-extended toluene diisocyanate (TDI) based hard segments. The formulations of the monol materials were maintained similar to those of flexible polyurethane foams with the exceptions that the conventional polyol was substituted by an oligomeric monofunctional polyether of ca. 1000 g/mol molecular weight. Plaques formed from these model systems were shown to be solid materials even at their relatively low molecular weights of 3000 g/mol and less, AFM phase images, for the first time, revealed the ability of the hard

  17. Drying Spirulina with Foam Mat Drying at Medium Temperature

    Directory of Open Access Journals (Sweden)

    Aji Prasetyaningrum

    2012-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-09-26

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

  19. Experiments to Populate and Validate a Processing Model for Polyurethane Foam: Additional Data for Structural Foams

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Rekha R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Giron, Nicholas Henry [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Long, Kevin Nicholas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Russick, Edward M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    We are developing computational models to help understand manufacturing processes, final properties and aging of structural foam, polyurethane PMDI. Th e resulting model predictions of density and cure gradients from the manufacturing process will be used as input to foam heat transfer and mechanical models. BKC 44306 PMDI-10 and BKC 44307 PMDI-18 are the most prevalent foams used in structural parts. Experiments needed to parameterize models of the reaction kinetics and the equations of motion during the foam blowing stages were described for BKC 44306 PMDI-10 in the first of this report series (Mondy et al. 2014). BKC 44307 PMDI-18 is a new foam that will be used to make relatively dense structural supports via over packing. It uses a different catalyst than those in the BKC 44306 family of foams; hence, we expect that the reaction kineti cs models must be modified. Here we detail the experiments needed to characteriz e the reaction kinetics of BKC 44307 PMDI-18 and suggest parameters for the model based on these experiments. In additi on, the second part of this report describes data taken to provide input to the preliminary nonlinear visco elastic structural response model developed for BKC 44306 PMDI-10 foam. We show that the standard cu re schedule used by KCP does not fully cure the material, and, upon temperature elevation above 150°C, oxidation or decomposition reactions occur that alter the composition of the foam. These findings suggest that achieving a fully cured foam part with this formulation may be not be possible through therma l curing. As such, visco elastic characterization procedures developed for curing thermosets can provide only approximate material properties, since the state of the material continuously evolves during tests.

  20. Insulating Foams Save Money, Increase Safety

    Science.gov (United States)

    2009-01-01

    Scientists at Langley Research Center created polyimide foam insulation for reusable cryogenic propellant tanks on the space shuttle. Meanwhile, a small Hialeah, Florida-based business, PolyuMAC Inc., was looking for advanced foams to use in the customized manufacturing of acoustical and thermal insulation. The company contacted NASA, licensed the material, and then the original inventors worked with the company's engineers to make a new material that was better for both parties. The new version, a high performance, flame retardant, flexible polyimide foam, is used for insulating NASA cryogenic propellant tanks and shows promise for use on watercraft, aircraft, spacecraft, electronics and electrical products, automobiles and automotive products, recreation equipment, and building and construction materials.

  1. Thermomechanical analyses of phenolic foam reinforced with glass fiber mat

    International Nuclear Information System (INIS)

    Zhou, Jintang; Yao, Zhengjun; Chen, Yongxin; Wei, Dongbo; Wu, Yibing

    2013-01-01

    Highlights: • Over 10% glass fiber was used to reinforce phenolic foam in the shape of glass fiber mat. • Nucleating agents were used together with glass fiber mat and improved tensile strength of phenolic foam by 215.6%. • Nucleating agents lead to a smaller bubble size of phenolic foam. • The glass transition temperature of phenolic foam remained unchanged during the reinforcement. - Abstract: In this paper, thermomechanical analysis (TMA) and dynamic mechanical analysis were employed to study the properties of phenolic foam reinforced with glass fiber mat. Unreinforced phenolic foam was taken as the control sample. Mechanical tests and scanning electron microscopy were performed to confirm the results of TMA. The results show that glass fiber mat reinforcement improves the mechanical performance of phenolic foam, and nucleating agents improve it further. Phenolic foam reinforced with glass fiber mat has a smaller thermal expansion coefficient compared with unreinforced foam. The storage modulus of the reinforced phenolic foam is also higher than that in unreinforced foam, whereas the loss modulus of the former is lower than that of the latter. The glass transition temperature of the phenolic foam matrix remains unchanged during the reinforcement

  2. Monitoring foam coarsening using a computer optical mouse as a ...

    Indian Academy of Sciences (India)

    In this paper, we present an experimental approach to track coarsening process of foam using a computer optical mouse as a dynamic laser speckle measurement sensor. The dynamics of foam coarsening and rearrangement events cause changes in the intensity of laser speckle backscattered from the foam. A strong ...

  3. Study of Thermal Properties of Cast Metal- Ceramic Composite Foams

    Directory of Open Access Journals (Sweden)

    Gawdzińska K.

    2017-12-01

    Full Text Available Owing to its properties, metallic foams can be used as insulation material. Thermal properties of cast metal-ceramic composite foams have applications in transport vehicles and can act as fire resistant and acoustic insulators of bulkheads. This paper presents basic thermal properties of cast and foamed aluminum, the values of thermal conductivity coefficient of selected gases used in foaming composites and thermal capabilities of composite foams (AlSi11/SiC. A certificate of non-combustibility test of cast aluminum-ceramic foam for marine applications was included inside the paper. The composite foam was prepared by the gas injection method, consisting in direct injection of gas into liquid metal. Foams with closed and open cells were examined. The foams were foaming with foaming gas consisting of nitrogen or air. This work is one of elements of researches connected with description of properties of composite foams. In author's other works acoustic properties of these materials will be presented.

  4. Foam Fractionation of Lycopene: An Undergraduate Chemistry Experiment

    Science.gov (United States)

    Wang, Yan; Zhang, Mingjie; Hu, Yongliang

    2010-01-01

    A novel experiment for the extraction of lycopene from tomato paste by foam fractionation is described. Foam fractionation is a process for separating and concentrating chemicals by utilizing differences in their surface activities. Extraction of lycopene by foam fractionation is a new method that has not been previously reported in the…

  5. Co-doped titanium oxide foam and water disinfection device

    Science.gov (United States)

    Shang, Jian-Ku; Wu, Pinggui; Xie, Rong-Cai

    2016-01-26

    A quaternary oxide foam, comprises an open-cell foam containing (a) a dopant metal, (b) a dopant nonmetal, (c) titanium, and (d) oxygen. The foam has the advantages of a high surface area and a low back pressure during dynamic flow applications. The inactivation of Escherichia coli (E. coli) was demonstrated in a simple photoreactor.

  6. The viscosity window of the silicate glass foam production

    DEFF Research Database (Denmark)

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

    2017-01-01

    in a maximum of foam expansion. The expansion maximum is obtained for different glasses (labware, E-glass, CRT panel, soda-lime-silica) by foaming with CaCO3 at isokom temperature and from literature data. In general, the viscosity window was found to be within 104–106 Pa s when foaming with MnO2 or metal...

  7. Developments in the uses of foamed bitumen in road pavements

    NARCIS (Netherlands)

    Jenkins, K.J.; Molenaar, A.A.A.; De Groot, J.L.A.; Van de Ven, M.E.C.

    2000-01-01

    Following the lapse in patent rights on foam-producing nozzles, the use of foamed bitumen for the improvement of road construction materials has become more accessible and as a result, it's use increased considerably in the 1990's. In addition, the applications of foamed bitumen process have

  8. 21 CFR 740.17 - Foaming detergent bath products.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Foaming detergent bath products. 740.17 Section...) COSMETICS COSMETIC PRODUCT WARNING STATEMENTS Warning Statements § 740.17 Foaming detergent bath products. (a) For the purpose of this section, a foaming detergent bath product is any product intended to be...

  9. Foam treatment for varicose veins; efficacy and safety

    African Journals Online (AJOL)

    Mamdouh Mohamed Kotb

    2013-04-08

    Apr 8, 2013 ... MUS method that generated a simple foam with air by means of a glass syringe. Mingo-Garcia6 developed a special device to produce foam with compressed air, and Tessari7 presented an original method of foam formation with two disposable syrin- ges and a three way-tap. Frullini8 published a different ...

  10. Adjoint-based optimization of a foam EOR process

    NARCIS (Netherlands)

    Namdar Zanganeh, M.; Kraaijevanger, J.F.B.M.; Buurman, H.W.; Jansen, J.D.; Rossen, W.R.

    2012-01-01

    We apply adjoint-based optimization to a Surfactant-Alternating-Gas foam process using a linear foam model introducing gradual changes in gas mobility and a nonlinear foam model giving abrupt changes in gas mobility as function of oil and water saturations and surfactant concentration. For the

  11. Monitoring foam coarsening using a computer optical mouse as a ...

    Indian Academy of Sciences (India)

    Abstract. In this paper, we present an experimental approach to track coarsening process of foam using a computer optical mouse as a dynamic laser speckle measurement sensor. The dynamics of foam coarsening and rearrangement events cause changes in the intensity of laser speckle backscat- tered from the foam.

  12. Foam for Enhanced Oil Recovery : Modeling and Analytical Solutions

    NARCIS (Netherlands)

    Ashoori, E.

    2012-01-01

    Foam increases sweep in miscible- and immiscible-gas enhanced oil recovery by decreasing the mobility of gas enormously. This thesis is concerned with the simulations and analytical solutions for foam flow for the purpose of modeling foam EOR in a reservoir. For the ultimate goal of upscaling our

  13. Mitigation of explosions of hydrogen–air mixtures using bulk materials and aqueous foam

    Science.gov (United States)

    Medvedev, S. P.; Khomik, S. V.; Mikhalkin, V. N.; Ivantsov, A. N.; Agafonov, G. L.; Cherepanov, A. A.; Cherepanova, T. T.; Betev, A. S.

    2018-01-01

    The objective of this work is to determine experimentally the effectiveness of protective barriers under conditions when blast waves are generated during premixed hydrogen– air combustion in various regimes. Experiments are conducted in a vertical tube having a diameter of 54 mm and a length of up to 2 m. Blast loads are produced by acceleration of premixed hydrogen–air flames in the tube with ring obstacles. Comparative tests are performed between protection barriers made of bulk materials with different densities and aqueous foams with different expansion ratios. It is demonstrated that the degree of blast load attenuation by an aqueous foam barrier increases with decreasing molecular weight of the filling gas and increasing density (decreasing expansion ratio) of the foam. An Aerosil barrier three times thicker than a titanium-dioxide one is found to have a similar attenuating effect on blast action. However, the mass per unit area of an Aerosil barrier is lower than titanium dioxide by a factor of 6 and is comparable to foam. The observed dependence of blast load attenuation on parameters of bulk materials and aqueous foams must be taken into account in systems designed to mitigate the consequences of accidental hydrogen release and combustion.

  14. Poly (vinylidene fluoride)/graphene nano-platelets electrically conductive composite foam for thermoelectric applications

    Science.gov (United States)

    Sun, Yu-Chen; Terakita, Daryl; Tseng, Alex C.; Naguib, Hani E.

    2015-04-01

    In this paper, we present the next generation of polymer based composite foam material fabricated from poly(vinylidene fluoride) (PVDF) and graphene nano-platelets (GNPs) as secondary fillers. We discovered that such composite material has thermoelectric properties and has the potential to be used in energy harvesting applications. The samples were fabricated though melt blending methods, which is a cheaper, simpler process and can be easily scaled up to industrial level for mass production. Our results indicate that melt blending processes can produce either similar or superior results compared to traditional solvent casting methods. In addition, we utilized a novel batch foaming method and successfully created closed-cell structure for the composite material. Our results also show that the thermal conductivity of PVDF/GNP foam samples have approximately an order of magnitude drop compared to solid samples, which is desired for thermoelectric materials. Furthermore, we observed a change in the electrical conductivity threshold of the GNP fillers after foaming. We report a Seebeck coefficient of 217 μV/K for 15 wt% GNP/PVDF foam samples, which is approximately 10 times higher than values reported previously.

  15. Experimental characterization of fire-induced response of rigid polyurethane foam

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.Y.; Gill, W.; Moore, J.W.; Hobbs, M.L.; Gritzo, L.A.; Moya, J.L.

    1995-12-31

    Reported is the result of an experimental investigation of fire-induced response of a 96 kg/m{sup 3} closed cell rigid polyurethane foam. The specimen is 0.37 m in diameter, and 152 mm thick, placed in a cylindrical test vessel. The fire condition is simulated by heating the bottom of the test vessel to 1283 K using a radiant heat source. Real-time x-ray shows that the degradation process involves the progression of a charring front into the virgin material. The charred region has a regular and graded structure consisting of a packed bubble outer layer and successive layers of thin shells. The layer-to-layer permeability appears to be poor. There are indications that gas vents laterally. The shell-like structure might be the result of lateral venting. Although the foam degradation process is quite complicated, the in-depth temperature responses in the uncharted foam appear to be consistent with steady state ablation. The measured temperature responses are well represented by the exponential distribution for steady state ablation. An estimate of the thermal diffusivity of the foam is obtained from the ablation model. The experiment is part of a more comprehensive program to develop material response models of foams and encapsulants.

  16. The production and characterization of topologically and mechanically gradient open-cell thermoplastic foams

    International Nuclear Information System (INIS)

    Sanami, M; Alderson, K L; Mottershead, B; Alderson, A; McDonald, S A; Withers, P J

    2014-01-01

    The development of longitudinally and radially gradient open-cell polyurethane foams is reported. Local and global mechanical properties and pore structure have been characterized using video extensometry with x−y strain-mapping capability, and x-ray microtomography (CT) and scanning electron microscopy (SEM), respectively. The local axial Poisson’s ratio varies in a smoothly continuous manner along the length of the longitudinally gradient foam from large negative (auxetic), through zero, to positive (conventional) values. The production of radially gradient foams having a coaxial core–sheath structure is reported for the first time. Two radially gradient foams have been produced, each displaying similar global negative axial Poisson’s ratio responses but with markedly different local axial Poisson’s ratio and local axial Young’s modulus behaviours. One of the radially gradient foams displays a positive Poisson’s ratio core and an auxetic sheath resulting from conventional and higher density re-entrant open-cell pore structures, respectively. (paper)

  17. Quasi-steady model for predicting temperature of aqueous foams circulating in geothermal wellbores

    Energy Technology Data Exchange (ETDEWEB)

    Blackwell, B.F.; Ortega, A.

    1983-01-01

    A quasi-steady model has been developed for predicting the temperature profiles of aqueous foams circulating in geothermal wellbores. The model assumes steady one-dimensional incompressible flow in the wellbore; heat transfer by conduction from the geologic formation to the foam is one-dimensional radially and time-dependent. The vertical temperature distribution in the undisturbed geologic formation is assumed to be composed of two linear segments. For constant values of the convective heat-transfer coefficient, a closed-form analytical solution is obtained. It is demonstrated that the Prandtl number of aqueous foams is large (1000 to 5000); hence, a fully developed temperature profile may not exist for representative drilling applications. Existing convective heat-transfer-coefficient solutions are adapted to aqueous foams. The simplified quasi-steady model is successfully compared with a more-sophisticated finite-difference computer code. Sample temperature-profile calculations are presented for representative values of the primary parameters. For a 5000-ft wellbore with a bottom hole temperature of 375{sup 0}F, the maximum foam temperature can be as high as 300{sup 0}F.

  18. Reactive decomposition of low density PMDI foam subject to shock compression

    Science.gov (United States)

    Alexander, Scott; Reinhart, William; Brundage, Aaron; Peterson, David

    Low density polymethylene diisocyanate (PMDI) foam with a density of 5.4 pounds per cubic foot (0.087 g/cc) was tested to determine the equation of state properties under shock compression over the pressure range of 0.58 - 3.4 GPa. This pressure range encompasses a region approximately 1.0-1.2 GPa within which the foam undergoes reactive decomposition resulting in significant volume expansion of approximately three times the volume prior to reaction. This volume expansion has a significant effect on the high pressure equation of state. Previous work on similar foam was conducted only up to the region where volume expansion occurs and extrapolation of that data to higher pressure results in a significant error. It is now clear that new models are required to account for the reactive decomposition of this class of foam. The results of plate impact tests will be presented and discussed including details of the unique challenges associated with shock compression of low density foams. Sandia National Labs is a multi-program lab managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Dept. of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  19. Experiments to populate and validate a processing model for polyurethane foam. BKC 44306 PMDI-10

    Energy Technology Data Exchange (ETDEWEB)

    Mondy, Lisa Ann [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rao, Rekha Ranjana [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shelden, Bion [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soehnel, Melissa Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); O' Hern, Timothy J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grillet, Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wyatt, Nicholas B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Russick, Edward Mark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hileman, Michael Bryan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Urquhart, Alexander [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Thompson, Kyle Richard [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Smith, David Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-03-01

    We are developing computational models to elucidate the expansion and dynamic filling process of a polyurethane foam, PMDI. The polyurethane of interest is chemically blown, where carbon dioxide is produced via the reaction of water, the blowing agent, and isocyanate. The isocyanate also reacts with polyol in a competing reaction, which produces the polymer. Here we detail the experiments needed to populate a processing model and provide parameters for the model based on these experiments. The model entails solving the conservation equations, including the equations of motion, an energy balance, and two rate equations for the polymerization and foaming reactions, following a simplified mathematical formalism that decouples these two reactions. Parameters for the polymerization kinetics model are reported based on infrared spectrophotometry. Parameters describing the gas generating reaction are reported based on measurements of volume, temperature and pressure evolution with time. A foam rheology model is proposed and parameters determined through steady-shear and oscillatory tests. Heat of reaction and heat capacity are determined through differential scanning calorimetry. Thermal conductivity of the foam as a function of density is measured using a transient method based on the theory of the transient plane source technique. Finally, density variations of the resulting solid foam in several simple geometries are directly measured by sectioning and sampling mass, as well as through x-ray computed tomography. These density measurements will be useful for model validation once the complete model is implemented in an engineering code.

  20. Fully recoverable rigid shape memory foam based on copper-catalyzed azide-alkyne cycloaddition (CuAAC) using a salt leaching technique.

    Science.gov (United States)

    Alzahrani, Abeer A; Saed, Mohand; Yakacki, Christopher M; Song, Han Byul; Sowan, Nancy; Walston, Joshua J; Shah, Parag K; McBride, Matthew K; Stansbury, Jeffrey W; Bowman, Christopher N

    2018-01-07

    This study is the first to employ the use of the copper-catalyzed azide-alkyne cycloaddition (CuAAC) polymerization to form a tough and stiff, porous material from a well-defined network possessing a high glass transition temperature. The effect of the network linkages formed as a product of the CuAAC reaction, i.e., the triazoles, on the mechanical behavior at high strain was evaluated by comparing the CuAAC foam to an epoxy-amine-based foam, which consisted of monomers with similar backbone structures and mechanical properties (i.e., T g of 115 °C and a rubbery modulus of 1.0 MPa for the CuAAC foam, T g of 125 °C and a rubbery modulus of 1.2 MPa for the epoxy-amine foam). When each foam was compressed uniformly to 80% strain at ambient temperature, the epoxy-amine foam was severely damaged after only reaching 70% strain in the first compression cycle with a toughness of 300 MJ/m 3 . In contrast, the CuAAC foam exhibited pronounced ductile behavior in the glassy state with three times higher toughness of 850 MJ/m 3 after the first cycle of compression to 80% strain. Additionally, when the CuAAC foam was heated above T g after each of five compression cycles to 80% strain at ambient temperature, the foam completely recovered its original shape while exhibiting a gradual decrease in mechanical performance over the multiple compression cycles. The foam demonstrated almost complete shape fixity and recovery ratios even through five successive cycles, indicative of "reversible plasticity", making it highly desirable as a glassy shape memory foams.

  1. Foam, composition and method of production

    Energy Technology Data Exchange (ETDEWEB)

    Ghali, R.

    1991-09-03

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

  2. Sclerotherapy and foam sclerotherapy for varicose veins.

    Science.gov (United States)

    Coleridge Smith, P

    2009-12-01

    To review published evidence concerning treatment of varicose veins using ultrasound-guided foam sclerotherapy (UGFS) to assess the safety and efficacy of this treatment. Medical literature databases including MedLine, Embase and DH-DATA were searched for recent literature concerning UGFS. Papers describing the early results and later outcome have been assessed and their main findings were included in this summary. Few randomized studies have been published in this field and much of the available data come from clinical series reported by individual clinicians. It is clear that foam sclerotherapy is far more effective than liquid sclerotherapy and that ultrasound imaging allows the treatment to be delivered accurately to affected veins. There is evidence that 3% polidocanol foam is no more effective than 1% polidocanol foam. The optimum ratio of gas to liquid is 4:1, although a range of ratios is reported in the published work. There is a wide variation in the volume used as well as the method by which it is injected. The use of carbon dioxide foam reduces the systemic complications, particularly visual disturbance, as compared with air foams. Very few serious adverse events have been reported in the literature despite the widespread use of this method. Rates of recanalization of saphenous trunks following UGFS are similar to those observed after endovenous laser and endovenous RF ablation of veins, as well as the residual incompetence after surgical treatment. UGFS is a safe and effective method of treating varicose veins. The relative advantages or disadvantages of this treatment in the longer term have yet to be published.

  3. Molded ultra-low density microcellular foams

    International Nuclear Information System (INIS)

    Rand, P.B.; Montoya, O.J.

    1986-07-01

    Ultra-low density (< 0.01 g/cc) microcellular foams were required for the NARYA pulsed-power-driven x-ray laser development program. Because of their extreme fragility, molded pieces would be necessary to successfully field these foams in the pulsed power accelerator. All of the foams evaluated were made by the thermally induced phase separation technique from solutions of water soluble polymers. The process involved rapidly freezing the solution to induce the phase separation, and then freeze drying to remove the water without destroying the foam's structure. More than sixty water soluble polymers were evaluated by attempting to make their solutions into foams. The foams were evaluated for shrinkage, density, and microstructure to determine their suitability for molding and meeting the required density and cell size requirements of 5.0 mg/cc and less than twenty μmeters. Several promising water soluble polymers were identified including the polyactylic acids, guar gums, polyactylamide, and polyethylene oxide. Because of thier purity, structure, and low shrinkage, the polyacrylic acids were chosen to develop molding processes. The initial requirements were for 2.0 cm. long molded rods with diameters of 1.0, 2.0. and 3.0 mm. These rods were made by freezing the solution in thin walled silicon rubber molds, extracting the frozen preform from the mold, and then freeze drying. Requirements for half rods and half annuli necessitated using aluminum molds. Again we successfully molded these shapes. Our best efforts to date involve molding annuli with 3.0 mm outside diameters and 2.0 mm inside diameters

  4. Uji Coba Dan Analisa Struktur Speed Bump Bahan Concrete Foam Diperkuat Batang Polymeric Foam Yang Digunakan Untuk Pembangkit Daya Listrik

    OpenAIRE

    Darmadi, Herry

    2017-01-01

    147015004 Incorrect speed bump profile shapes can harm road users passing by. This study focuses on making speed bump profiles of concrete foam materials and polymeric foam reinforced TKKS fibers in order to obtain better and safer standard bump structure designs according to standard. The objectives of this study were to analyze the weakness and toughness of the speed bump structure of concrete foam and polymeric foam reinforced Fibers of Empty Fruit Bunches (EFB) subjected to free fall i...

  5. Relative merits of polystyrene foam and paper in hot drink cups: Implications for packaging

    Science.gov (United States)

    Hocking, Martin B.

    1991-11-01

    An analysis of the overall relative merits of the use of uncoated paper vs molded polystyrene bead foam in single-use 8-oz cups is described here as a manageable example of the use of paper vs plastics in packaging. In raw material requirements the paper cup required about 2.5 times its finished weight of raw wood and about the same hydrocarbon fueling requirement as is needed for the polystyrene foam cup. To process the raw materials about six times as much steam, 13 times as much electric power, and twice as much cooling water are consumed to produce the paper cup as compared to the polystyrene foam cup. Emission rates to air are similar and to water are generally higher for the paper cup. Virtually all primary use factors favor polystyrene foam over paper. Once used both cup types may be recycled. Landfill disposal of the two items under dry conditions will occupy similar landfill volumes after compaction and will confer similarly slow to nonexistent decomposition to either option. Under wet conditions polystyrene foam will not readily degrade, but may help other materials to do so. Paper under wet conditions will biodegrade to produce methane, a significant greenhouse gas, biochemical oxygen demand to any leachate, and instability to the land surface during the process. Both materials can be incinerated cleanly in a municipal waste stream with the option of energy recovery, to yield an ash volume of 2% 5% of the incoming waste volume. Overall this analysis would suggest that polystyrene foam, with an extension to plastics in general, should be given more evenhanded consideration relative to paper in packaging applications than is currently the case.

  6. Experiments for foam model development and validation.

    Energy Technology Data Exchange (ETDEWEB)

    Bourdon, Christopher Jay; Cote, Raymond O.; Moffat, Harry K.; Grillet, Anne Mary; Mahoney, James F. (Honeywell Federal Manufacturing and Technologies, Kansas City Plant, Kansas City, MO); Russick, Edward Mark; Adolf, Douglas Brian; Rao, Rekha Ranjana; Thompson, Kyle Richard; Kraynik, Andrew Michael; Castaneda, Jaime N.; Brotherton, Christopher M.; Mondy, Lisa Ann; Gorby, Allen D.

    2008-09-01

    A series of experiments has been performed to allow observation of the foaming process and the collection of temperature, rise rate, and microstructural data. Microfocus video is used in conjunction with particle image velocimetry (PIV) to elucidate the boundary condition at the wall. Rheology, reaction kinetics and density measurements complement the flow visualization. X-ray computed tomography (CT) is used to examine the cured foams to determine density gradients. These data provide input to a continuum level finite element model of the blowing process.

  7. Shock Wave Structure in Polyurethane Foam

    OpenAIRE

    ONODERA, Hideki; TAKAYAMA, Kazuyoshi

    1994-01-01

    Shock wave propagation in polyurethane (PU(R)) foam was experimentally studied. The experiment was conducted in a shock tube by measuring pressure along the PU(R) foam in a shock tube, by means of holographic interferometry and streak camera recording. It was found that the stress-strain curve of PU(R) has an inflection point. When the pressure behind the incident shock wave was below the inflection-point pressure P_c, the wave impedance ratio of the incident shock wave and transmitted pressu...

  8. Sound absorption property of openpore aluminum foams

    Directory of Open Access Journals (Sweden)

    WANG Fang

    2007-02-01

    Full Text Available This paper presents a study on sound absorption property of aluminum foam by evaluating its sound absorption coefficients using standing wave tube method. Experimental results showed that the average values of sound absorption coefficients (over the test frequency range are all above 0.4, which indicate very good sound absorption property of the aluminum foams. The sound absorption coefficient is affected by frequency and pore structure, and reaches its maximum value at around 1 000 Hz. With the increase of porosity and decrease of cell diameter, the sound absorption coefficient values increase.

  9. Vertical velocities from proper motions of red clump giants

    Science.gov (United States)

    López-Corredoira, M.; Abedi, H.; Garzón, F.; Figueras, F.

    2014-12-01

    of the warp amplitude in a time of about one hundred Myr. Conclusions: The vertical motion in the warp apparently indicates that the main S-shaped structure of the warp is a long-lived feature, whereas the perturbation that produces an irregularity in the southern part is most likely a transient phenomenon. But we need higher accuracy in the systematic errors of proper motions to confirm this tentative detection of vertical motion in the outer disk. With the use of the Gaia end-of-mission products together with spectroscopically classified red clump giants, the precision in vertical motions can be increased by an order of magnitude at least.

  10. A proper metaphysics for cognitive performance.

    Science.gov (United States)

    Van Orden, Guy C; Moreno, Miguel A; Holden, John G

    2003-01-01

    The general failure to individuate component causes in cognitive performance suggests the need for an alternative metaphysics. The metaphysics of control hierarchy theory accommodates the fact of self-organization in nature and the possibility that intentional actions are self-organized. One key assumption is that interactions among processes dominate their intrinsic dynamics. Scaling relations in response time variability motivate this assumption in cognitive performance.

  11. Sterilized PP/HMSPP cushion foams for medical and food packaging applications

    International Nuclear Information System (INIS)

    Cardoso, Elisabeth C.L.; Lima, L. Filipe C.P.; Parra, Duclerc F.; Lugao, Ademar B.; Bueno, N.R.; Gasparin, Eleosmar

    2009-01-01

    Treatment with gamma radiation is becoming a common process for the sterilization of packages, mostly made of natural or synthetic plastics, used in aseptic processing of foods and pharmaceuticals. Packaging materials may be irradiated either prior or after filling; the irradiation prior to filling is usually chosen for dairy products, processed food, beverages, pharmaceuticals and medical devices. Cushion foams are used to help protect fragile items during moving transport. Shock, vibration and damage are avoided by the cushioning effect and chances of product damage are reduced. It is easy to use and perforated for easy tearing. Cushion foams are employed to wrap glasses, plates, crockery, lamps, electronics and other breakable items. This paper presents special cushion foams to be used for medical and food packaging applications; so, these foams will be gamma irradiated before getting in contact with these special articles. Foams were previously produced from a 50% blending Polypropylene homopolymer / High Melt Strength Polypropylene (HMSPP) thereof, that presented following results for properties assessed: melt flow index, 230 deg C - 3.67 g/10 minutes; crystallinity = 47%; melt strength, at 200 deg C = 7.3 cN. This admixture was further fed into the barrel of a single-screw extruder, Rheomex 332 p, equipped with 3:1,33 d screw and 19/33 special screw for foaming, with standard controller and monitored panel, temperature controller (2 channels), melt temperature (2 channels) and melt pressure (4 channels). By using a 175/200/210/220/165/25 (deg C) profile temperature, and after attaining a homogeneous melting, a given amount of physical blowing agent (nitrogen) was injected and mixed with the polymer melt stream to produce the foam. Foamed extrudate was subjected to sterilization radiation doses: 25, 50, 75 and 100 kGy and further evaluated as per: appearance (whiteness / yellowness) and temperature dependent oxidative-induction time (TOIT) tests, by comparing

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  13. Solid phase extraction of Cu(II as diethyldithiocarbamate (DDTC complex by polyurethane foam

    Directory of Open Access Journals (Sweden)

    Sant'Ana Otoniel D.

    2003-01-01

    Full Text Available This paper presents a study about the sorption of copper-diethyldithiocarbamate complex onto polyurethane foam (PUF. It was observed that the maximum sorption of Cu(II (80 or 150 µg L-1 was verified at pH 6.8 in presence of 4.5 x 10-5 mol L-1 DDTC. The shaking time needed to achieve the equilibrium was 40 minutes. From these data, a kinetic characterization was performed by applying three models, which revealed that a film diffusion process was a rate-determining mechanism. Results also indicated that a ether-like solvent extraction was the sorption mechanism. The investigation of many metallic ions as concomitants showed that the sorption by foam is relatively selective and it can be enhanced by using a suitable masking agent or incrementing the foam mass.

  14. In vivo response to an implanted shape memory polyurethane foam in a porcine aneurysm model.

    Science.gov (United States)

    Rodriguez, Jennifer N; Clubb, Fred J; Wilson, Thomas S; Miller, Matthew W; Fossum, Theresa W; Hartman, Jonathan; Tuzun, Egemen; Singhal, Pooja; Maitland, Duncan J

    2014-05-01

    Cerebral aneurysms treated by traditional endovascular methods using platinum coils have a tendency to be unstable, either due to chronic inflammation, compaction of coils, or growth of the aneurysm. We propose to use alternate filling methods for the treatment of intracranial aneurysms using polyurethane-based shape memory polymer (SMP) foams. SMP polyurethane foams were surgically implanted in a porcine aneurysm model to determine biocompatibility, localized thrombogenicity, and their ability to serve as a stable filler material within an aneurysm. The degree of healing was evaluated via gross observation, histopathology, and low vacuum scanning electron microscopy imaging after 0, 30, and 90 days. Clotting was initiated within the SMP foam at time 0 (<1 h exposure to blood before euthanization), partial healing was observed at 30 days, and almost complete healing had occurred at 90 days in vivo, with minimal inflammatory response. Copyright © 2013 Wiley Periodicals, Inc.

  15. In vivo tissue response following implantation of shape memory polyurethane foam in a porcine aneurysm model

    Science.gov (United States)

    Rodriguez, Jennifer N.; Clubb, Fred J.; Wilson, Thomas S.; Miller, Matthew W.; Fossum, Theresa W.; Hartman, Jonathan; Tuzun, Egemen; Singhal, Pooja; Maitland, Duncan J.

    2014-01-01

    Cerebral aneurysms treated by traditional endovascular methods using platinum coils have a tendency to be unstable, either due to chronic inflammation, compaction of coils, or growth of the aneurysm. We propose to use alternate filling methods for the treatment of intracranial aneurysms using polyurethane based shape memory polymer (SMP) foams. SMP polyurethane foams were surgically implanted in a porcine aneurysm model to determine biocompatibility, localized thrombogenicity, and their ability to serve as a stable filler material within an aneurysm. The degree of healing was evaluated via gross observation, histopathology and low vacuum scanning electron microscopy (LV-SEM) imaging after zero, thirty and ninety days. Clotting was initiated within the SMP foam at time zero (less than one hour exposure to blood prior to euthanization), partial healing was observed at thirty days, and almost complete healing had occurred at ninety days in vivo, with minimal inflammatory response. PMID:23650278

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

    International Nuclear Information System (INIS)

    Barikani, H.; Sarai, M.

    2001-01-01

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

  17. Experimental study on foam coverage on simulated longwall roof

    Science.gov (United States)

    Reed, W.R.; Zheng, Y.; Klima, S.; Shahan, M.R.; Beck, T.W.

    2018-01-01

    Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27 percent of respirable coal mine dust can be attributed to longwall shield movement, and developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine the ability of the foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used: compressed air and blower air. Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For compressed air foam in 3.3 m/s (650 fpm) ventilation, 98 percent of agent A was intact while 95 percent of agent B was intact on the roof at three minutes after application. At 30 minutes after application, 94 percent of agent A was intact while only 20 percent of agent B remained. For blower air in 3.3 m/s (650 fpm) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 min after application, 74 to 92 percent of foam agent A remained, while 3 to 50 percent of foam agent B remained. Compressed air foam seems to remain intact for longer durations and is easier to apply than blower air foam. However, more water drained from the foam when using compressed air foam, which demonstrates that blower air foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able to withstand a typical face ventilation velocity, establishing this technique’s potential for longwall shield dust control. PMID:29563765

  18. Proper battery system design for GAS experiments

    Science.gov (United States)

    Calogero, Stephen A.

    1992-10-01

    The purpose of this paper is to help the GAS experimenter to design a battery system that meets mission success requirements while at the same time reducing the hazards associated with the battery system. Lead-acid, silver-zinc and alkaline chemistry batteries will be discussed. Lithium batteries will be briefly discussed with emphasis on back-up power supply capabilities. The hazards associated with different battery configurations will be discussed along with the controls necessary to make the battery system two-fault tolerant.

  19. Dynamic Moisture Sorption and Desorption in Fumed Silica-filled Silicone Foam

    Energy Technology Data Exchange (ETDEWEB)

    Trautschold, Olivia Carol [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-02

    Characterizing dynamic moisture sorption and desorption in fumed silica-filled silicone foam is necessary for determining material compatibilities and life predictions, particularly in sealed environments that may be exposed to a range of environmental conditions. Thermogravimetric analysis (TGA) and near infrared spectroscopy (NIR) were performed on S5470 fumed silica-filled silicone foam to determine the weight percent of moisture at saturation. Additionally, TGA was used to determine the time, temperature, and relative humidity levels required for sorption and desorption of physisorbed moisture in S5470.

  20. Effects of SiC and MgO on aluminabased ceramic foams filters

    Directory of Open Access Journals (Sweden)

    CAO Da-li

    2007-11-01

    Full Text Available Alumina-based foam ceramic filters were fabricated by using alumina, SiC, magnesia powder as major materials. It has been found that this ceramic filter has a uniform macrostructure for filtering molten metals. The influences of SiC and magnesia content, the sintering temperatures on ceramic properties were discussed. Aluminabased foam ceramic filters containing 2.2 mass% magnesia and 7.6 mass% SiC has a compressive strength of 1.36 MPa and a thermal shock resistance of 5 times. Its main phases after 1 hour sintering at 1 500 consist of alumina, silicon carbide, spinel and mullite.

  1. Determination of Acreage Thermal Protection Foam Loss From Ice and Foam Impacts

    Science.gov (United States)

    Carney, Kelly S.; Lawrence, Charles

    2015-01-01

    A parametric study was conducted to establish Thermal Protection System (TPS) loss from foam and ice impact conditions similar to what might occur on the Space Launch System. This study was based upon the large amount of testing and analysis that was conducted with both ice and foam debris impacts on TPS acreage foam for the Space Shuttle Project External Tank. Test verified material models and modeling techniques that resulted from Space Shuttle related testing were utilized for this parametric study. Parameters varied include projectile mass, impact velocity and impact angle (5 degree and 10 degree impacts). The amount of TPS acreage foam loss as a result of the various impact conditions is presented.

  2. The Improvement of Foam Concrete Geoecoprotective Properties in Transport Construction

    Science.gov (United States)

    Svatovskaya, Larisa; Kabanov, Alexander; Sychov, Maxim

    2017-10-01

    The article analyses 2 kinds of properties of silica sol foam concrete: technical and geoecoprotective ones. Foam concrete stabilized with silica sol foam has lower heat conductivity resulting in fuel saving. Foam concrete obtained according to sol absorption technology has lower water absorption and is good enough for blocking to prevent the environment pollution. Pollution blocking can be achieved by two methods. The first method is saturation of an article affected by oil products with silica sol. The second method is to create a special preventive protection using silica sol screen. The article shows geoecoprotective properties of protein foam soil systems.

  3. The Effect of Foam Rolling on Recovery Between Two Eight Hundred Metre Runs

    Directory of Open Access Journals (Sweden)

    D’Amico Anthony

    2017-06-01

    Full Text Available With the increased popularity of foam rolling as a means of recovery, it is important to establish the exact manner in which the practice is useful. The purpose of this study was to examine the impact of foam rolling on recovery between two 800 m runs. Sixteen trained males (mean ± sd; age, 20.5 ± .5 yr; average 800 m treadmill run time, 145.2 ± 1.8 s participated in the study, using a randomized, crossover design. The subjects completed two 800 m runs on a treadmill, separated by a 30 min rest, during which time a foam rolling protocol or passive rest period was performed. The speed of each run was as fast as possible. Subjects had access to speed controls, but were blinded to the actual speed. Blood lactate concentration and V. $\\it V^{.}$ CO2 were measured prior to and following each run. Stride length, 800 m run time, and hip extension were measured during each run. V. $\\it V^{.}$ CO2, stride length, 800 m run time, and hip extension were not significantly different between conditions (p > .05. For blood lactate, no statistical interaction was found between condition and time (p > .05. Foam rolling between two 800 m runs separated by 30 min performed by trained male runners does not alter performance.

  4. Polyurethane Foam-Filled Skull Replica of Craniosynostosis for Surgical Training.

    Science.gov (United States)

    Jeong, Yeon Jin; Lee, Jun Yong

    2016-05-01

    Craniosynostosis has a relatively low incidence in the general population and its treatment requires cautious approaches. For these reasons, patients are usually referred to several specialists or a medical center. Therefore, most trainees and young surgeons do not have any chances to experience patients of craniosynostosis, but learn about it only from textbooks. And for a surgeon who tries to operate on a craniosynostosis patient, it is hard to make a proper preoperative plan.The authors suggest a polyurethane foam-filled skull replica of craniosynostosis for trainees that can also be used in planning a craniosynostosis operation.

  5. Proper Support Improves Online Student Success

    Directory of Open Access Journals (Sweden)

    Julia Sweitzer

    2005-10-01

    Full Text Available To ensure success of students enrolled in distance learning courses factors such as training for instructors, allocation of resources, administrative support, perceived relevance of content to the student's career or personal interests, degree of student support, amount and nature of feedback and amount of time/effort required as well as establishment of learning communities are critical. Unfortunately, these services are not always in place when colleges first begin to venture into distance education. In addition, faculty members are often reluctant to develop courses in the absence of sufficient support from administrators and technical staff, not only for themselves, but their students as well. This article will discuss these issues and why they are important for student success.

  6. Sensitivity and uncertainty analysis of a polyurethane foam decomposition model

    Energy Technology Data Exchange (ETDEWEB)

    HOBBS,MICHAEL L.; ROBINSON,DAVID G.

    2000-03-14

    Sensitivity/uncertainty analyses are not commonly performed on complex, finite-element engineering models because the analyses are time consuming, CPU intensive, nontrivial exercises that can lead to deceptive results. To illustrate these ideas, an analytical sensitivity/uncertainty analysis is used to determine the standard deviation and the primary factors affecting the burn velocity of polyurethane foam exposed to firelike radiative boundary conditions. The complex, finite element model has 25 input parameters that include chemistry, polymer structure, and thermophysical properties. The response variable was selected as the steady-state burn velocity calculated as the derivative of the burn front location versus time. The standard deviation of the burn velocity was determined by taking numerical derivatives of the response variable with respect to each of the 25 input parameters. Since the response variable is also a derivative, the standard deviation is essentially determined from a second derivative that is extremely sensitive to numerical noise. To minimize the numerical noise, 50-micron elements and approximately 1-msec time steps were required to obtain stable uncertainty results. The primary effect variable was shown to be the emissivity of the foam.

  7. Advanced slab polyurethane foam with feather touch; Soft feather urethane foam no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Y.; Ono, H. [Toyota Motor Corp., Aichi (Japan); Mori, A.; Yamaguchi, N.; Nakamura, T. [Bridgestone Corp., Tokyo (Japan)

    1997-10-01

    Automotive seat plays an important part, which are not only retention of sitting position, but also comfort and high-class feeling. Wadding, which is a part of the seat, is a key component for the sitting comfortableness. This paper is concerned with advanced slab polyurethane foam with feather touch feeling. The compounding of formation, foaming process and reliability of mass production is studied. 2 refs., 10 figs., 3 tabs.

  8. Antibacterial potency of V.A.C. GranuFoam Silver(®) Dressing.

    Science.gov (United States)

    Sachsenmaier, Saskia; Peschel, Andreas; Ipach, Ingmar; Kluba, Torsten

    2013-10-01

    V.A.C.(®) GranuFoam™ therapy is regularly used in the surgical therapy of infected wounds and soft tissue injuries. Silver nanoparticles can destroy bacterial cell walls and inhibit enzymes for cell replication. Silver dressings are therefore successfully used for many indications in wound therapy. In this study, we investigated the antimicrobial potency of ionic silver released from the silver-coated V.A.C.(®) GranuFoam™ during vacuum therapy. Silver dressing was exposed to agar plates populated with bacteria to measure silver release. A total of 15 agar plates colonised with either Staphylococcus aureus populations or with Staphylococcus epidermidis, were loaded with V.A.C. GranuFoam Silver(®) Dressing polyurethane foam (KCI, San Antonio, Texas). Each of 13 pieces of silver-coated foam was applied to an agar plate. Two plates were loaded with conventional black foam without any coating. After connecting to a vacuum pump, the vacuum therapy of the 15 plates lasted 5 days. The zone of inhibition of bacterial growth around the foam was measured daily. Silver release was also determined as a function of time. At each time point, there was evidence of silver in the agar independent of bacterial colonisation. The S. aureus agar showed a consecutive increase in silver concentration from baseline upon 48 h after exposure to the negative pressure of V.A.C. therapy. An increasing mean silver level after 48, 72 and 96 h was measured under V.A.C. therapy with a peak value after 120 h. In contrast, the results from the S. epidermidis plates did not follow a linear pattern. At the beginning of vacuum therapy, we documented a rise in silver concentration. After 48-96h, the silver levels fluctuated. A maximum zone of inhibition in both bacterial colonised plates (S. aureus and S. epidermidis) was found 39 h after the start of the V.A.C. GranuFoam Silver(®) therapy. From our results, we confirmed the antimicrobial effect of the silver ions against S. aureus and S

  9. Method of Preventing Shrinkage of Aluminum Foam Using Carbonates

    Directory of Open Access Journals (Sweden)

    Takashi Nakamura

    2011-12-01

    Full Text Available Metallic foams are commonly produced using titanium hydride as a foaming agent. Carbonates produce aluminum foam with a fine and homogenous cell structure. However, foams produced using carbonates show marked shrinkage, which is clearly different from those produced using titanium hydride. It is essential for practical applications to clarify foam shrinkage and establish a method of preventing it. In this research, cell structures were observed to study the shrinkage of aluminum foam produced using carbonates. The cells of foam produced using dolomite as a foaming agent connected to each other with maximum expansion. It was estimated that foaming gas was released through connected cells to the outside. It was assumed that cell formation at different sites is effective in preventing shrinkage induced by cell connection. The multiple additions of dolomite and magnesium carbonate, which have different decomposition temperatures, were applied. The foam in the case with multiple additions maintained a density of 0.66 up to 973 K, at which the foam produced using dolomite shrank. It was verified that the multiple additions of carbonates are effective in preventing shrinkage.

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

    Science.gov (United States)

    Jo, Choonghee; Naguib, Hani E.

    2007-04-01

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

  11. Failure mechanism of PMI foam core sandwich beam in bending

    Directory of Open Access Journals (Sweden)

    Wang Bo

    2015-01-01

    Full Text Available Polymethacrylimide (PMI foams have been widely applied in aerospace engineering as the core material of sandwich structures. This paper proposes a modified model to predict the constitutive relation of PMI foams and compares it to existing testing data. The study is then applied to the investigation of the failure mechanism of PMI foam core sandwich beams in bending. Corresponding bending tests were carried out where a complex failure process was observed through a high-speed camera. Numerical model of the foregoing sandwich beam is developed, in which the maximum principal stress criteria is used to predict damage propagation in PMI foam core. Both results from tests and numerical simulation validate the reliability of the theoretical prediction of the failure of PMI foam core sandwich beam using the proposed modified model of PMI foams. This study provides a theoretic tool for the design of sandwich structures with PMI foam core.

  12. The 3D structure of real polymer foams.

    Science.gov (United States)

    Montminy, Matthew D; Tannenbaum, Allen R; Macosko, Christopher W

    2004-12-01

    The intricate structure of polymeric foams may be examined using 3D imaging techniques such as MRI or X-ray tomography followed by image processing. Using a new 3D image processing technique, six images of polyurethane foams were analyzed to create computerized 3D models of the samples. Measurements on these models yielded distributions of many microstructural features, including strut length and window and cell shape distributions. Nearly 8000 struts, 4000 windows, and 376 cells were detected and measured in six polyurethane foam samples. When compared against previous theories and studies, these measurements showed that the structure of real polymeric foams differs significantly from both equilibrium models and aqueous foams. For example, previous studies of aqueous foams showed that about 70% of foam windows were pentagons. In the polymeric sample studied here, only 55% of windows were pentagonal.

  13. 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.

  14. SAG Foam Flooding in Carbonate Rocks

    NARCIS (Netherlands)

    Boeije, C.S.; Rossen, W.R.

    2017-01-01

    Foam is used in gas-injection EOR processes to reduce the mobility of gas, resulting in greater volumetric sweep. SAG (Surfactant Alternating Gas) is a preferred method of injection as it results in greater injectivity in the field, but designing a successful process

  15. Filler functionality in edible solid foams

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2016-01-01

    We review the functionality of particulate ingredients in edible brittle foams, such as expanded starchy snacks. In food science and industry there is not a complete awareness of the full functionality of these filler ingredients, which can be fibers, proteins, starch granules and whole grains.

  16. Multiaxial yield behaviour of Al replicated foam

    Science.gov (United States)

    Combaz, E.; Bacciarini, C.; Charvet, R.; Dufour, W.; Mortensen, A.

    2011-09-01

    Multiaxial experiments are performed on replicated aluminium foam using a custom-built apparatus. The foam structure is isotropic, and features open monomodal pores 75 μm in average diameter. Plane stress ( σ1, σ2, σ3=0) and axisymmetric ( σ1, σ2=σ3) yield envelopes are measured using cubical specimens, supplemented by tests on hollow cylindrical and uniaxial samples. In addition to the three stress components at 0.2% offset strain, the computer-controlled testing apparatus also measures the three instantaneous displacement vectors. Results show that the shape of the yield surface is independent of the relative density of the foam in the explored range (13-28%). Strain increment vectors lie, within error, roughly normal to the line traced through data points in stress space. Replicated foams feature asymmetric yield behaviour between tension and compression. The data additionally show an influence on the yield surface of the third stress tensor invariant (i.e., of the Lode angle). Simple general expressions for the yield surface are fitted to the data, leading to conclude that their behaviour is slightly better captured by parabolic rather than elliptic expressions dependent on all three stress invariants.

  17. Thermo-mechanical characterization of silicone foams

    Energy Technology Data Exchange (ETDEWEB)

    Rangaswamy, Partha [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Nickolaus A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cady, Carl M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewis, Matthew W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-01

    Cellular solids such as elastomeric foams are used in many structural applications to absorb and dissipate energy, due to their light weight (low density) and high energy absorption capability. In this paper we will discuss foams derived from S5370, a silicone foam formulation developed by Dow Corning. In the application presented, the foam is consolidated into a cushion component of constant thickness but variable density. A mechanical material model developed by Lewis (2013), predicts material response, in part, as a function of relative density. To determine the required parameters for this model we have obtained the mechanical response in compression for ambient, cold and hot temperatures. The variable density cushion provided samples sufficient samples so that the effect of sample initial density on the mechanical response could be studied. The mechanical response data showed extreme sensitivity to relative density. We also observed at strains corresponding to 1 MPa a linear relationship between strain and initial density for all temperatures. Samples taken from parts with a history of thermal cycling demonstrated a stiffening response that was a function of temperature, with the trend of more stiffness as temperature increased above ambient. This observation is in agreement with the entropic effects on the thermo-mechanical behavior of silicone polymers. In this study, we present the experimental methods necessary for the development of a material model, the testing protocol, analysis of test data, and a discussion of load (stress) and gap (strain) as a function of sample initial densities and temperatures

  18. Formulation, Preparation, and Characterization of Polyurethane Foams

    Science.gov (United States)

    Pinto, Moises L.

    2010-01-01

    Preparation of laboratory-scale polyurethane foams is described with formulations that are easy to implement in experiments for undergraduate students. Particular attention is given to formulation aspects that are based on the main chemical reactions occurring in polyurethane production. This allows students to develop alternative formulations to…

  19. Nano-Aramid Fiber Reinforced Polyurethane Foam

    Science.gov (United States)

    Semmes, Edmund B.; Frances, Arnold

    2008-01-01

    Closed cell polyurethane and, particularly, polyisocyanurate foams are a large family of flexible and rigid products the result of a reactive two part process wherein a urethane based polyol is combined with a foaming or "blowing" agent to create a cellular solid at room temperature. The ratio of reactive components, the constituency of the base materials, temperature, humidity, molding, pouring, spraying and many other processing techniques vary greatly. However, there is no known process for incorporating reinforcing fibers small enough to be integrally dispersed within the cell walls resulting in superior final products. The key differentiating aspect from the current state of art resides in the many processing technologies to be fully developed from the novel concept of milled nano pulp aramid fibers and their enabling entanglement capability fully enclosed within the cell walls of these closed cell urethane foams. The authors present the results of research and development of reinforced foam processing, equipment development, strength characteristics and the evolution of its many applications.

  20. Modeling of Sandwich Sheets with Metallic Foam

    International Nuclear Information System (INIS)

    Mata, H.; Jorge, R. Natal; Fernandes, A. A.; Parente, M. P. L.; Santos, A.; Valente, R. A. F.

    2011-01-01

    World-wide vehicles safety experts agree that significant further reductions in fatalities and injuries can be achieved as a result of the use of new lightweight and energy absorbing materials. On this work, the authors present the development and evaluation of an innovative system able to perform reliable panels of sandwich sheets with metallic foam cores for industrial applications. The mathematical model used to describe the behavior of sandwich shells with metal cores foam is presented and some numerical examples are presented. In order to validate those results mechanical experiments are carried out. Using the crushable foam constitutive model, available on ABAQUS, a set of different mechanical tests were simulated. There are two variants of this model available on ABAQUS: the volumetric hardening model and the isotropic hardening model. As a first approximation we chose the isotropic hardening variant. The isotropic hardening model available uses a yield surface that is an ellipse centered at the origin in the p-q stress plane. Based on this constitutive model for the foam, numerical simulations of the tensile and bulge test will be conducted. The numerical results will be validated using the data obtained from the experimental results.

  1. 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

  2. Foam-forming properties of Ilex paraguariensis (mate saponin: foamability and foam lifetime analysis by Weibull equation

    Directory of Open Access Journals (Sweden)

    Janine Treter

    2010-01-01

    Full Text Available Saponins are natural soaplike foam-forming compounds widely used in foods, cosmetic and pharmaceutical preparations. In this work foamability and foam lifetime of foams obtained from Ilex paraguariensis unripe fruits were analyzed. Polysorbate 80 and sodium dodecyl sulfate were used as reference surfactants. Aiming a better data understanding a linearized 4-parameters Weibull function was proposed. The mate hydroethanolic extract (ME and a mate saponin enriched fraction (MSF afforded foamability and foam lifetime comparable to the synthetic surfactants. The linearization of the Weibull equation allowed the statistical comparison of foam decay curves, improving former mathematical approaches.

  3. Spray Foam Exterior Insulation with Stand-Off Furring

    Energy Technology Data Exchange (ETDEWEB)

    Herk, Anastasia [IBACOS, Inc., Pittsburgh, PA (United States); Baker, Richard [IBACOS, Inc., Pittsburgh, PA (United States); Prahl, Duncan [IBACOS, Inc., Pittsburgh, PA (United States)

    2014-03-01

    IBACOS, in collaboration with GreenHomes America, was contracted by the New York State Energy Research and Development Authority to research exterior wall insulation solutions. This research investigated cost-effective deep energy retrofit (DER) solutions for improving the building shell exterior while achieving a cost-reduction goal, including reduced labor costs to reach a 50/50 split between material and labor. The strategies included exterior wall insulation plus energy upgrades as needed in the attic, mechanical and ventilation systems, and basement band joist, walls, and floors. The work can be integrated with other home improvements such as siding or window replacement. This strategy minimizes physical connections to existing wall studs, encapsulates existing siding materials (including lead paint) with spray foam, and creates a vented rain screen assembly to promote drying. GreenHomes America applied construction details created by IBACOS to a test home. 2x4 framing members were attached to the wall at band joists and top plates using 'L' clips, with spray foam insulating the wall after framing was installed. Windows were installed simultaneously with the framing, including extension jambs. The use of clips in specific areas provided the best strength potential, and 'picture framing' the spray foam held the 2x4s in place. Short-term testing was performed at this house, with monitoring equipment installed for long-term testing. Testing measurements will be provided in a later report, as well as utility impact (before and after), costs (labor and materials), construction time, standard specifications, and analysis for the exterior wall insulation strategy.

  4. Spray Foam Exterior Insulation with Stand-Off Furring

    Energy Technology Data Exchange (ETDEWEB)

    Herk, Anatasia [IBACOS, Inc., Pittsburgh, PA (United States); Baker, Richard [IBACOS, Inc., Pittsburgh, PA (United States); Prahl, Duncan [IBACOS, Inc., Pittsburgh, PA (United States)

    2014-03-01

    IBACOS, in collaboration with GreenHomes America, was contracted by the New York State Energy Research and Development Authority to research exterior wall insulation solutions. This research investigated cost-effective deep energy retrofit (DER) solutions for improving the building shell exterior while achieving a cost-reduction goal, including reduced labor costs to reach a 50/50 split between material and labor. The strategies included exterior wall insulation plus energy upgrades as needed in the attic, mechanical and ventilation systems, and basement band joist, walls, and floors. The work can be integrated with other home improvements such as siding or window replacement. This strategy minimizes physical connections to existing wall studs, encapsulates existing siding materials (including lead paint) with spray foam, and creates a vented rain screen assembly to promote drying. GreenHomes America applied construction details created by IBACOS to a test home. 2x4 framing members were attached to the wall at band joists and top plates using "L" clips, with spray foam insulating the wall after framing was installed. Windows were installed simultaneously with the framing, including extension jambs. The use of clips in specific areas provided the best strength potential, and "picture framing" the spray foam held the 2x4s in place. Short-term testing was performed at this house, with monitoring equipment installed for long-term testing. Testing measurements will be provided in a later report, as well as utility impact (before and after), costs (labor and materials), construction time, standard specifications, and analysis for the exterior wall insulation strategy.

  5. JNK1 Mediates Lipopolysaccharide-Induced CD14 and SR-AI Expression and Macrophage Foam Cell Formation

    Directory of Open Access Journals (Sweden)

    Dong An

    2018-01-01

    Full Text Available Foam cell formation is the key process in the development of atherosclerosis. The uptake of oxidized low-density lipoprotein (oxLDL converts macrophages into foam cells. We recently reported that lipopolysaccharide (LPS-induced foam cell formation is regulated by CD14 and scavenger receptor AI (SR-AI. In this study, we employed pharmaceutical and gene knockdown approaches to determine the upstream molecular mediators, which control LPS-induced foam cell formation. Our results demonstrated that the specific c-Jun N-terminal kinase (JNK pathway inhibitor, SP600125, but neither the specific inhibitor of extracellular signaling-regulated kinase (ERK kinase MEK1/2, U0126, nor the specific inhibitor of p38 MAPK, SB203580, significantly blocks LPS-induced oxLDL uptake, suggesting that the JNK pathway is the upstream mediator of LPS-induced oxLDL uptake/foam cell formation. To address whether JNK pathway mediates LPS-induced oxLDL uptake is due to JNK pathway-regulated CD14 and SR-AI expression, we assessed whether the pharmaceutical inhibitor of JNK influences LPS-induced expression of CD14 and SR-AI. Our results indicate that JNK pathway mediates LPS-induced CD14 and SR-AI expression. To conclusively address the isoform role of JNK family, we depleted JNK isoforms using the JNK isoform-specific siRNA. Our data showed that the depletion of JNK1, but not JNK2 blocked LPS-induced CD14/SR-AI expression and foam cell formation. Taken together, our results reveal for the first time that JNK1 is the key mediator of LPS-induced CD14 and SR-AI expression in macrophages, leading to LPS-induced oxLDL uptake/foam cell formation. We conclude that the novel JNK1/CD14/SR-AI pathway controls macrophage oxLDL uptake/foam cell formation.

  6. Additive Manufacturing of Tooling for Refrigeration Cabinet Foaming Processes

    Energy Technology Data Exchange (ETDEWEB)

    Post, Brian K [ORNL; Nuttall, David [ORNL; Cukier, Michael Z [ORNL; Hile, Michael B [ORNL

    2016-07-29

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

  7. The role of clinically-relevant parameters on the cohesiveness of sclerosing foams in a biomimetic vein model.

    Science.gov (United States)

    Carugo, Dario; Ankrett, Dyan N; O'Byrne, Vincent; Wright, David D I; Lewis, Andrew L; Hill, Martyn; Zhang, Xunli

    2015-11-01

    We have recently reported on the development of a biomimetic vein model to measure the performance of sclerosing foams. In this study we employed the model to compare the commercially-available Varithena(®) (polidocanol injectable foam) 1% varicose vein treatment (referred to as polidocanol endovenous microfoam, or PEM) with physician compounded foams (PCFs) made using different foam generation methods (Double Syringe System and Tessari methods) and different foam formulations [liquid to gas ratios of 1:3 or 1:7; gas mixtures composed of 100% CO2, various CO2:O2 mixtures and room air (RA)]. PCFs produced using the DSS method had longer dwell times (DTs) (range 0.54-2.21 s/cm in the 4 mm diameter vein model) than those of the corresponding PCFs produced by the Tessari technique (range 0.29-0.94 s/cm). PEM had the longest DT indicating the best cohesive stability of any of the foams produced (2.92 s/cm). Other biomimetic model variables investigated included effect of vessel size, delayed injection and rate of plug formation (injection speed). When comparing the 4 and 10 mm vessel diameters, the DTs seen in the 10 mm vessel were higher than those observed for the 4 mm vessel, as the vein angle had been reduced to 5° to allow for foam plug formation. PCF foam performance was in the order RA > CO2:O2 (35:65) ≅ CO2:O2 (65:35) > CO2; PEM had a longer DT than all PCFs (22.10 s/cm) except that for RA made by DSS which was similar but more variable. The effect of delayed injection was also investigated and the DT for PEM remained the longest of all foams with the lowest percentage deviation with respect to the mean values, indicating a consistent foam performance. When considering rate of plug formation, PEM consistently produced the longest DTs and this was possible even at low plug expansion rates (mean 29.5 mm/s, minimum 20.9 mm/s). The developed vein model has therefore demonstrated that PEM consistently displays higher foam stability and cohesiveness when compared

  8. Study of the relationships between nuclear decontamination foams stability and their physicochemical properties; Etude des relations entre la stabilite des mousses de decontamination nucleaire et leurs proprietes physico-chimiques

    Energy Technology Data Exchange (ETDEWEB)

    Dame, C

    2006-03-15

    The LPAD (French Atomic Energy Commission) develops innovative processes in the frame of the future dismantling of nuclear facilities. Formulations were developed using high viscosified foams stabilized by biodegradable nonionic surfactants: alkyl poly-glucosides and viscosifiers (xanthan gum), which allow us to increase the foam lifetime and thus contact time of chemical reactants with the facility walls. We have considered the relationships between physicochemical properties and foam stability through the exploration of the foam at three different scales: from the molecular range (micelles, surface tension and visco-elasticity), to the film and Plateau border range (XR reflectivity, surface shear viscosity) and to macroscopic range, meaning the whole foam (foaminess, liquid fraction and wall film thickness evolution). Finally, exploratory study is presented concerning simultaneous foam three scales characterisation by small angle neutron scattering. (author)

  9. Study of the Penetration and Diffusion Characteristics of Inorganic Solidified Foam in Rock Fractures

    Directory of Open Access Journals (Sweden)

    Yi Lu

    2017-01-01

    Full Text Available To explore the penetration and diffusion law in coal and rock fractures when inorganic solidified foam (ISF is used to prevent coal fire, the penetration experiment was conducted; the results showed that the penetration pressure fluctuates within a certain range and decreases with the diffusion distance. In the XY plane, the diffusion pattern presents an ellipsoid shape, and the diffusion area becomes increasingly large over time; in the XZ plane, the foam fluid penetration changes from dense to loose in the X direction and it does not undergo downward penetration and diffuses via its own weight in the Z direction; in the YZ plane, it is loose on the left and dense on the right. The viscosity of ISF was tested and then the time-varying formula was fitted. The formula of the effective diffusion radius for foam fluid diffusing in the fracture channel was determined theoretically. The permeability coefficient and other related parameters were calculated in terms of the penetration pressure and diffusion time of two monitoring points. At last, the prediction formula of effective diffusion distance of foam fluid was verified with the remaining seven monitoring points and all the relative error of monitoring is within 10%.

  10. Per- and polyfluoroalkyl substances in firefighting foam concentrates and water samples collected near sites impacted by the use of these foams.

    Science.gov (United States)

    Dauchy, Xavier; Boiteux, Virginie; Bach, Cristina; Rosin, Christophe; Munoz, Jean-François

    2017-09-01

    To extinguish large-scale fuel fires, fluorosurfactant based foams (FSBFs) were developed in the 1960s and have been used ever since. In this study, 154 per- and polyfluoroalkyl substances (PFASs) including 122 emerging PFASs used as surfactants in FSBFs were sought in nine different foam concentrates. Field investigations were also carried out in the vicinity of four sites where FSBFs are or were intensively used (two airports, a training center for firefighters and an oil storage depot after a large explosion). In the foam concentrates, only three PFASs were quantified with concentrations ranging from 22,500 to 3,188,000 μg/L. Thirteen emerging PFASs were also identified in these samples based on their mass transitions and intensities. Overall, each foam was a mixture of at least two classes of PFASs. In three concentrates, none of the 122 emerging PFASs were identified as the main ingredient. A perfluoroalkyl acid precursor oxidation assay was therefore performed, and revealed the presence of high amounts of unidentified PFASs. In the vicinity of the four investigated sites, several PFASs were systematically quantified in all of the samples collected downstream of the sites. PFAS profiles were heavily influenced by parameters such as route of PFAS transport after use (runoff, seepage, direct discharge), time elapsed since the cessation of firefighting activities, and firefighting foam composition. The PFAS concentrations found around the investigated sites are the highest recorded in France and resulted in the closure of certain drinking water resources. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. A linear peristaltic MRF/foam actuator

    Science.gov (United States)

    Larsen, J. J.; Jenkins, C. H.; Korde, U. A.

    2007-04-01

    Magneto-rheological fluid (MRF) was first developed in the late 1940s. MRF consists of iron or other ferrous particles, typically on the order of 1 - 10 μm characteristic dimension, dispersed in a host carrier fluid, usually oil or water. In the presence of a magnetic field, the alignment of the iron particles along field lines results in the effective rheological properties of the composite fluid to be modified. In the "off" state (no field applied), the fluid has similar viscous properties to the host fluid. In the "on" state (field applied), the viscosity and yield stress can be significantly modified. Recently, MRF has been of interest in a number of novel devices, for example, for variable damping such as in automotive shock absorbers. In the present work, we briefly describe our initial investigations into variable damping MRF/foam devices. Open-cell polymer foam blocks were infused with commercial MRF and subjected to magnetic fields of various strengths. Drop tests were conducted by dropping a small indenter from a fixed platform and observing the rebound height as a function of applied field strength. The difference in rebound height can be directly related to loss of energy through damping. In the tests conducted, the energy absorbed by the MRF/foam increased from about 60% in the off-state device to over 90% in the on-state device. One of the difficulties encountered in performing the drop tests and providing credible data interpretation was that the MRF/foam itself changed dimensions under applied field. The iron particles in the fluid were attracted to the magnet and thus caused constriction of the foam block. Peristalsis is the process of involuntary and successive wave-like muscular contractions by which food is moved through the digestive tract. The esophagus, stomach, and intestines all move and/or mix food and liquid by peristalsis. Peristalsis is also used to move lymph through the lymphatic system. Inspired by biological peristalsis

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

    Science.gov (United States)

    Stackpoole, Mairead; Chien, Jennifer; Schaeffler, Michelle

    2004-01-01

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

  13. Dynamics and Statics of Interfaces in Proper and Improper Ferroelastics

    Science.gov (United States)

    Sujatha, Narasimhan

    1990-01-01

    We have studied the dynamics and statics of twin boundaries and interfaces in proper and improper ferroelastic materials. We have studied three-dimensional improper ferroelastic transitions in perovskites that undergo cubic -trigonal transitions, while confining ourselves to one -dimensional proper ferroelastic transitions. The stability of elastic twin boundaries is studied within the 1D solitary wave elastic phi^4 and phi^6 models developed by Barsch and Falk, respectively. Static twin boundaries, represented by kink type solutions, are found to be linearly stable, whereas only moving heterophase inclusions are found to be nonlinearly stable in some cases. The correction due to the phase shift suffered by an ultrasonic wave in passing through a twinned bicrystal in elastic constant measurements is evaluated by performing a numerical calculation based on the linear stability equation. The twin boundaries are found to reduce the travel time, thereby contributing a positive correction to the measured elastic constants. This effect is most pronounced close to the transition temperature. Although the periodic solutions of the local phi^4 model, which represent ferroelectric twin bands in 1D are frequently referred to in the literature as unstable, we are not aware of any proof in the literature and are, therefore, also presenting a proof of the linear instability of these solutions. A Landau-Ginzburg theory for cubic-trigonal improper transitions in ABX_3 perovskites has been developed along similar lines as that for cubic -tetragonal transitions, including the rotation gradient terms. The antiphase and twin boundaries, along with the strain distribution and the stresses required to sustain them, are determined. Specific application to LaAlO _3 is carried out and the results are seen to be in marked contrast with those observed for SrTiO _3 by Cao and Barsch.

  14. Wall effects in Stokes experiment with a liquid foam

    Science.gov (United States)

    Gao, Haijing; Subramani, Hariprasad; Harris, Michael; Basaran, Osman

    2011-11-01

    Liquid foams are widely used in numerous applications ranging from the oil and gas industry to beauty, healthcare, and household products industries. A fundamental understanding of the relationships between the properties of liquid foams and their flow responses is, however, still in its infancy compared to that involving the fluid dynamics of simple fluids. In this talk, the flow of a dry liquid foam around a spherical bead, i.e. the Stokes problem for liquid foams, is studied experimentally. In contrast to previous work (cf. Cantat 2006), the focus of the present research is to probe the effect of a solid wall that is located a few bubble radii from the bead. The new experimental results show that the elastic modulus of dry liquid foams is directly proportional to the surface tension of the foaming agents and inversely proportional to the average bubble size in the foams, in agreement with previous theoretical and experimental studies. The experiments further show that the close proximity of the solid wall causes profound structural changes to the gas bubbles as the foam flows past the bead. A good understanding of these structural changes and how they can affect the elastic modulus of foams can be indispensable in formulating improved models for accurately describing the dynamical response of foams within the realm of continuum mechanics.

  15. Nanoparticle-stabilized CO₂ foam for CO₂ EOR application

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ning [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States); Lee, Robert [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States); Yu, Jianjia [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States); Li, Liangxiong [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States); Bustamante, Elizabeth [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States); Khalil, Munawar [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States); Mo, Di [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States); Jia, Bao [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States); Wang, Sai [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States); San, Jingshan [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States); An, Cheng [New Mexico Petroleum Recovery Research Center, Socorro, NM (United States)

    2015-01-31

    The purpose of this project was to develop nanoparticle-stabilized CO₂ foam for CO₂ -EOR application, in which nanoparticles instead of surfactants are used for stabilizing CO₂ foam to improve the CO₂ sweep efficiency and increase oil recovery. The studies included: (1) investigation of CO₂ foam generation nanoparticles, such as silica nanoparticles, and the effects of particle concentration and surface properties, CO₂/brine ratio, brine salinity, pressure, and temperature on foam generation and foam stability; (2) coreflooding tests to understand the nanoparticle-stabilized CO₂ foam for waterflooded residual oil recovery, which include: oil-free coreflooding experiments with nanoparticle-stabilized CO₂ foam to understand the transportation of nanoparticles through the core; measurements of foam stability and CO₂ sweep efficiency under reservoir conditions to investigate temperature and pressure effects on the foam performance and oil recovery as well as the sweep efficiency in different core samples with different rock properties; and (3) long-term coreflooding experiments with the nanoparticle- stabilized CO₂ foam for residual oil recovery. Finally, the technical and economical feasibility of this technology was evaluated.

  16. Structural Foams of Biobased Isosorbide-Containing Copolycarbonate

    Directory of Open Access Journals (Sweden)

    Stefan Zepnik

    2017-01-01

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

  17. Injectable silk foams for the treatment of cervical insufficiency

    Science.gov (United States)

    Fournier, Eric P.

    Preterm birth is the leading cause of neonatal mortality, resulting in over 4,000 deaths each year. A significant risk factor for preterm birth is cervical insufficiency, the weakening and subsequent deformation of cervical tissue. Cervical insufficiency is both detectable and treatable but current treatments are lacking. The most common approach requires multiple invasive procedures. This work investigates the injection of silk foams, a minimally-invasive method for supporting cervical tissue. Silk offers many advantages for use as a biomaterial including strength, versatility, and biocompatibility. Injectable silk foams will minimize patient discomfort while also providing more targeted and personalized treatment. A battery of mechanical testing was undertaken to determine silk foam response under physiologically relevant loading and environmental conditions. Mechanical testing was paired with analysis of foam morphology and structure that illustrated the effects of injection on pore geometry and size. Biological response to silk foams was evaluated using an in vitro degradation study and subcutaneous in vivo implantation in a mouse model. Results showed that foams exceeded the mechanical requirements for stiffening cervical tissue, although the current injection process limits foam size. Injection was shown to cause measurable but localized foam deformation. This work indicates that silk foams are a feasible treatment option for cervical insufficiency but challenges remain with foam delivery.

  18. Relevant factors affecting the outcome of ultrasound guided foam sclerotherapy of the great saphenous vein

    Directory of Open Access Journals (Sweden)

    Giorgio Falaschi

    2013-09-01

    Full Text Available Ultrasound guided foam sclerotherapy (UGFS constitutes a valid ablative treatment for superficial vein diseases for the great saphenous vein (GSV, but no standardized protocol for its execution has yet been defined. Different variable factors involved in this procedure influence the final outcome and clinical results. The aim of our study was to analyze the respective influence on efficacy and side effects of three variable factors (foam volume, foam concentration, and contact time between the foam and the endothelium for UGFS procedures for GSV insufficiency in order to select the best protocol for treatment. A retrospective analysis was made of UGFS procedures (190 patients, 201 legs performed for GSV insufficiency in our institute from January 2007 to January 2010. All great saphenous veins included in our study exhibited a trans-ostial reflux and caliber range was 7-11 mm. In all cases, foam was prepared according to the Tessari method, using polidocanol (POL and a gas mixture of CO2 (70% and filtered room air (30%, in a proportion of 1:4. A single injection procedure in the GSV was performed under Doppler ultrasound guidance at mid to lower third of the thigh. Legs were randomly assigned to one of three different treatment protocols: - Group A (71 legs: POL 3%, mean foam volume 4.5 cc, intermittent groin pressure 5 min, supine bed rest 10 min; - Group B (61 legs: POL 2%, mean foam volume 9 cc, intermittent groin pressure 5 min, supine bed rest 10 min; - Group C (69 legs: POL 2%, mean foam volume 9 cc, continuous groin pressure 5 min followed by intermittent groin pressure 5 min, continuous leg compression 5 min, supine bed rest 10 min. Efficacy of treatment and occurrence of side effects were evaluated in each group at two weeks and again at two years after the procedure and the cumulative results compared. Analysis of outcomes did not show any significant difference between the complete obliteration rate (P=0.825 or occurrence of local

  19. Rigid Polyurethane Foam Thermal Insulation Protected with Mineral Intumescent Mat

    Directory of Open Access Journals (Sweden)

    Kirpluks Mikelis

    2014-12-01

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

  20. Carbon Dioxide and Nitrogen Infused Compressed Air Foam for Depopulation of Caged Laying Hens.

    Science.gov (United States)

    Gurung, Shailesh; White, Dima; Archer, Gregory; Styles, Darrel; Zhao, Dan; Farnell, Yuhua; Byrd, James; Farnell, Morgan

    2018-01-03

    Depopulation of infected poultry flocks is a key strategy to control and contain reportable diseases. Water-based foam, carbon dioxide inhalation, and ventilation shutdown are depopulation methods available to the poultry industry. Unfortunately, these methods have limited usage in caged layer hen operations. Personnel safety and welfare of birds are equally important factors to consider during emergency depopulation procedures. We have previously reported that compressed air foam (CAF) is an alternative method for depopulation of caged layer hens. We hypothesized that infusion of gases, such as carbon dioxide (CO₂) and nitrogen (N₂), into the CAF would reduce physiological stress and shorten time to cessation of movement. The study had six treatments, namely a negative control, CO₂ inhalation, N₂ inhalation, CAF with air (CAF Air), CAF with 50% CO₂ (CAF CO₂), and CAF with 100% N₂ (CAF N₂). Four spent hens were randomly assigned to one of these treatments on each of the eight replication days. A total of 192 spent hens were used in this study. Serum corticosterone and serotonin levels were measured and compared between treatments. Time to cessation of movement of spent hens was determined using accelerometers. The addition of CO₂ in CAF significantly reduced the foam quality while the addition of N₂ did not. The corticosterone and serotonin levels of spent hens subjected to foam (CAF, CAF CO₂, CAF N₂) and gas inhalation (CO₂, N₂) treatments did not differ significantly. The time to cessation of movement of spent hens in the CAF N₂ treatment was significantly shorter than CAF and CAF CO₂ treatments but longer than the gas inhalation treatments. These data suggest that the addition of N₂ is advantageous in terms of shortening time to death and improved foam quality as compared to the CAF CO₂ treatment.