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Sample records for high-fluence swelling behavior

  1. Evolution of arsenic in high fluence plasma immersion ion implanted silicon : Behavior of the as-implanted surface

    NARCIS (Netherlands)

    Vishwanath, V.; Demenev, E.; Giubertoni, D.; Vanzetti, L.; Koh, A. L.; Steinhauser, G.; Pepponi, G.; Bersani, M.; Meirer, F.; Foad, M. A.

    2015-01-01

    High fluence (>1015 ions/cm2) low-energy (3 + on (1 0 0) silicon was investigated, with the focus on stability and retention of the dopant. At this dose, a thin (∼3 nm) amorphous layer forms at the surface, which contains about 45% arsenic (As) in a silicon and oxygen matrix. The presence of silicon

  2. Swelling and curling behaviors of articular cartilage.

    Science.gov (United States)

    Setton, L A; Tohyama, H; Mow, V C

    1998-06-01

    A new experimental method was developed to quantify parameters of swelling-induced shape change in articular cartilage. Full-thickness strips of cartilage were studied in free-swelling tests and the swelling-induced stretch, curvature, and areal change were measured. In general, swelling-induced stretch and curvature were found to increase in cartilage with decreasing ion concentration, reflecting an increasing tendency to swell and "curl" at higher swelling pressures. An exception was observed at the articular surface, which was inextensible for all ionic conditions. The swelling-induced residual strain at physiological ionic conditions was estimated from the swelling-induced stretch and found to be tensile and from 3-15 percent. Parameters of swelling were found to vary with sample orientation, reflecting a role for matrix anisotropy in controlling the swelling-induced residual strains. In addition, the surface zone was found to be a structurally important element, which greatly limits swelling of the entire cartilage layer. The findings of this study provide the first quantitative measures of swelling-induced residual strain in cartilage ex situ, and may be readily adapted to studies of cartilage swelling in situ.

  3. Prediction of Swelling Behavior of Addis Ababa Expansive Soil ...

    African Journals Online (AJOL)

    In this study a simple hyperbolic mathematical model is used to predict the swelling behavior of an expansive soil from Addis Ababa. The main parameters that are needed to run the model are the applied pressure and initial dry density. The other parameters of the model including the initial slope of the swell-time curve, the ...

  4. Swelling behavior of PEMFC during conditioning

    Directory of Open Access Journals (Sweden)

    J. Parrondo

    2007-09-01

    Full Text Available Polymeric cation exchange membranes (PEMFC are used in fuel cell technology. These membranes act as a physical barrier between anode and cathode, but diffusion through the membrane should allow protons to be carried from anode to cathode at a rate sufficient to supply energy requirements. They avoid any direct reaction of oxygen and hydrogen that would diminish fuel cell efficiency. Membranes have to be conditioned before use. This conditioning step changes membrane counterions and modifies their water content, which has an effect on their diffusion coefficients. In order to analyse and quantify the effect of conditioning techniques on membrane performance various experiments with Nafion 117 cation exchange membranes were carried out. Membranes were conditioned using various methods to change the charged cation in the membrane. The reactives used were ultrapure water, nitric acid, hydrochloric acid, hydrogen peroxide, sodium chloride, potassium chloride and ethylene glycol, all at room temperature. Some conditioning methods were carried out using solvents heated to 100 ºC. Water content was indirectly monitored by measuring membrane swelling. Results show that membrane conditioning with strong acids followed by treatment with water increases membrane water content by about 5%. Using high-temperature treatment the water content also increases. Water uptake or release from membranes is analysed in terms of water activity.

  5. RHEOLOGY AND SCALING BEHAVIOR OF SWELLING CLAY ...

    African Journals Online (AJOL)

    2012-12-31

    Dec 31, 2012 ... The scaling variable (ϕp/ϕpc-1), suggested in percolation theory to describe rheological behavior near percolation transition, acts to collapse G' data ... The purpose of rheology in oscillation mode is to better include/understand the evolution of clay dispersions with the bentonite concentration for different ...

  6. Swelling behavior of poly (2-hydroxyethyl methacrylate copolymer gels

    Directory of Open Access Journals (Sweden)

    Sari S.M. Chabane

    2013-09-01

    Full Text Available Hydrogels based on 2-hydroxyethyl methacrylate/dimethyl-aminoethyl methacrylate copolymers were prepared by gamma radiation-inducedco-polymerization at low temperature (−78°C. The swelling behavior of hydrogels was studied by immersion of the polymer discs in buffered solutions at pH from 2 to 10. The hydration process was followed gravimetrically by measuring the water uptake of the discs as a function of time. The results obtained have shown that the swelling behavior is reversible and depends on the polymer nature. Moreover, polymeric discs exhibited a good stability after repeating cycles of hydration in different buffer solutions. Scanning electron microscopy analysis reveals that hydrogel porosity can be controlled.

  7. Swelling, Compressibility, and Phase Behavior of Soft Ionic Microgels

    Science.gov (United States)

    Denton, Alan

    Soft colloids have inspired great attention recently for their rich and tunable materials properties. Particular interest has focused on microgels - microscopic cross-linked polymer gel particles that, when dispersed in water, become swollen and can acquire charge through dissociation of counterions. Electrostatic interparticle interactions strongly influence the structure and thermodynamics of ionic microgel suspensions*. Permeability to solvent molecules and small ions creates a competition between elastic and electrostatic forces that determines equilibrium particle sizes. Swelling can be controlled by adjusting temperature, pH, and salt concentration, with applications to chemical/biosensing and targeted drug delivery. By combining molecular dynamics and Monte Carlo simulation with Poisson-Boltzmann theory of electrostatics and Flory-Rehner theory of swollen polymer networks, we investigate swelling and compressibility of ionic microgel particles and implications for thermodynamic phase behavior of bulk suspensions at concentrations approaching and exceeding hard-sphere close packing. Predictions for particle size and osmotic pressure are compared with available experimental data. This work was supported by the National Science Foundation under Grant No. DMR-1106331.

  8. Investigation of Pre- and Post-Swelling Behavior of Elastomeric Material

    Directory of Open Access Journals (Sweden)

    M Akhtar

    2013-06-01

    Full Text Available In the last ten years, a new type of modern polymer, known as swelling elastomer, has been used extensively as a sealing element in the oil and gas industry. These elastomers have been instrumental in various new applications such as water shut off, zonal isolation, and sidetracking. Though swell packers can significantly reduce costs and increase productivity, their failure can lead to serious losses. The integrity and reliability of swelling elastomer seals under different field conditions is a major concern. The investigation of changes in material behavior over a specified swelling period is a necessary first step for performance evaluation of elastomer seals. The current study is based on experimental analysis of changes in geometric and mechanical behavior (hardness, tensile, compressive, bulk of an elastomeric material due to swelling. Tests were carried out before and after various stages of swelling. Specimens were placed in saline water (0.6% and 12% concentrations at a temperature of 50°C, with the total swelling period being one month. Swelling, hardness, compression, and bulk tests were conducted using disc samples, while ring samples were used for tensile experiments. A small test rig was designed and constructed for determination of bulk modulus. Stress-strain curves under tension and compression, and pressure volumetric-strain curves were obtained for specimens subjected to different swelling periods. Due to the fast-swell nature of the elastomer, there were sharp changes in mechanical properties within the first few days of swelling for both salinities. Elastic modulus derived from tensile and compressive tests showed a 90% decrease in the first few days. Bulk modulus showed fluctuation in its variation with an increasing swelling period. There was a small effect of salinity only during the first 5 or 6 days.

  9. Deuterium accumulation in carbon materials at high fluence

    Energy Technology Data Exchange (ETDEWEB)

    Pisarev, A., E-mail: pisarev@plasma.mephi.r [Moscow Engineering and Physics Institute, Moscow, Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Tanabe, T. [Kyushu University, Hakozaki, Fukuoka 812-8581 (Japan); Emmoth, B. [Royal Institute of Technology, KTH, VR, 16440 Kista (Sweden); Trifonov, N. [Moscow Engineering and Physics Institute, Moscow, Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Rusinov, A., E-mail: rusinov@plasma.mephi.r [Moscow Engineering and Physics Institute, Moscow, Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Stepanov, S.; Gasparyan, Yu. [Moscow Engineering and Physics Institute, Moscow, Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Spitsyn, A.; Khripunov, B. [Russian Research Center ' Kurchatov Institute' , Pl. Kurchatova 1, 123182 Moscow (Russian Federation)

    2009-06-15

    D retention in fine grain graphite MPG-8 and carbon fiber composite NB31 after exposure to plasma was investigated by means of thermal desorption spectroscopy. It was observed, that deuterium accumulation in the two materials was similar in the region of the fluence of 10{sup 22}-4 x 10{sup 24} D{sup +}/m{sup 2}, though NB31 retains about twice as much. The retention in MPG-8 reveals no saturation at high fluences and no flux dependence in the range of (0.5-3.5) x 10{sup 20} D{sup +}/m{sup 2} s. The difference between polished and unpolished samples, as well as between samples kept in air for various times after irradiation was within the experimental uncertainty.

  10. Altered osmotic swelling behavior of proteoglycan-depleted bovine articular cartilage using high frequency ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Q; Zheng, Y P; Leung, G; Mak, A F T [Department of Health Technology and Informatics, Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Lam, W L; Guo, X [Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hong Kong (China); Lu, H B; Qin, L [Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Chinese University of Hong Kong, Hong Kong (China)], E-mail: ypzheng@ieee.org

    2008-05-21

    Swelling behavior is an electrochemical mechanical property of articular cartilage. It plays an important role in weight bearing and joint lubrication. In this study, the altered transient and inhomogeneous swelling behavior of the degenerated articular cartilage was observed and quantified in situ using ultrasound. Three groups of bovine patellar articular cartilage samples (n = 10 x 3) were obtained and digested by trypsin for 10, 20 and 30 min respectively to mimic different levels of degeneration. The osmotic-free shrinkage and swelling behavior induced by changing the concentration of the bathing saline solution from 0.15 M to 2 M and then back to 0.15 M were characterized using high-frequency ultrasound (central frequency = 35 MHz) before and after digestion. It was found that the degenerated cartilage specimens showed a weaker shrinkage-swelling behavior compared with the normal cartilage samples. However, no significant differences in the peak shrinkage or swelling strains were observed between different groups. The absolute values of the peak shrinkage strain significantly (p < 0.05) decreased by 45.4%, 42.1% and 50.6% respectively after the trypsin digestion for 10, 20 and 30 min, but such significance was not demonstrated for the peak swelling strains. Due to the potential alterations in the collagen-PG matrix during trypsin digestion, the correlation between the swelling strain and the shrinkage strain of the degenerated samples changed slightly in comparison with the normal samples. The proposed ultrasound method has been successfully used to measure the transient and inhomogeneous swelling behavior of the degenerated articular cartilage and has the potential for the characterization of osteoarthritis.

  11. Study of High Fluence Radiation-induced Swelling and Hardening under Light Water Reactor Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Golubov, Stanislav I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Barashev, Alexander V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stoller, Roger E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    This report documents a comprehensive model that has been developed to enable simulations of microstructural evolution under the irradiation conditions typical of light water reactor (LWR) internal components. The model, which accounts cascade production of point defects and vacancy, interstitial faulted dislocation loops, interstitial clusters migrating one-dimensionally and the evolution of the network dislocation structure, has been parameterized to account damage accumulation in austenitic stainless steels. Nucleation and growth of an ensemble of cavities is based on accounting the residual and produced by irradiation He atoms and existence of the dislocation and production biases. Additional applications and potential future developments for the model are also discussed.

  12. Coupling behavior of the pH/temperature sensitive hydrogels for the inhomogeneous and homogeneous swelling

    Science.gov (United States)

    Mazaheri, H.; Baghani, M.; Naghdabadi, R.; Sohrabpour, S.

    2016-08-01

    In this work, a model is developed to continuously predict homogeneous and inhomogeneous swelling behavior of pH/temperature sensitive PNIPAM hydrogels. Employing the model, homogeneous swelling of the pH/temperature sensitive hydrogel is investigated for free and biaxial constrained swelling cases. Comparing the model results with the experimental data available in the literature, the validity of the model is confirmed. The model is then employed to investigate inhomogeneous swelling of a spherical shell on a hard core both analytically and numerically for pH or temperature variations. In this regard, numerical tools are developed via preparing a user defined subroutine in ABAQUS software. Then, the complicated problem of contact between the hydrogel shell and a micro-channel with rigid walls is also investigated. Considering the results, we can say that the model is applicable for solving engineering boundary value problem of pH/temperature sensitive hydrogels.

  13. Influence of nickel and beryllium content on swelling behavior of copper irradiated with fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Singh, B.N.; Garner, F.A.; Edwards, D.J. [Pacific Northwest National Lab., Richland, WA (United States); Evans, J.H.

    1996-10-01

    In the 1970`s, the effects of nickel content on the evolution of dislocation microstructures and the formation and growth of voids in Cu-Ni alloys were studied using 1 MeV electrons in a high voltage electron microscope. The swelling rate was found to decrease rapidly with increasing nickel content. The decrease in the swelling rate was associated with a decreasing void growth rate with increasing nickel content at irradiation temperatures up to 450{degrees}C. At 500{degrees}C, both void size and swelling rate were found to peak at 1 and 2% Ni, respectively, and then to decrease rapidly with increasing nickel content. However, recent work has demonstrated that the swelling behavior of Cu-5%Ni irradiated with fission neutrons is very similar for that of pure copper. The present experiments were designed to investigate this apparent discrepancy.

  14. RHEOLOGY AND SCALING BEHAVIOR OF SWELLING CLAY DISPERSIONS

    Directory of Open Access Journals (Sweden)

    S. Chaoui

    2015-07-01

    Full Text Available The microstructure and scaling of rheological properties of colloidal gels of bentonite investigated as a function of volume fraction and strength of interparticle interaction over a range of volume fractions, elastic modulus is well described with a scaling law functions of volume fractions, while the role of interparticle attractions can be accounted for by expressing these rheological properties as (f/fg-1n, where fg captures the strength of particle interaction and n the microstructure. The scaling variable (fp/fpc-1, suggested in percolation theory to describe rheological behavior near percolation transition, acts to collapse G’ data suggesting that along lines of constant (f/fg-1 these gels are rheologically identical.

  15. RHEOLOGY AND SCALING BEHAVIOR OF SWELLING CLAY DISPERSIONS

    Directory of Open Access Journals (Sweden)

    S. CHAOUI

    2012-12-01

    Full Text Available The microstructure and scaling of rheological properties of colloidal gels of bentonite investigated as a function of volume fraction and strength of interparticle interaction over a range of volume fractions, elastic modulus is well described with a scaling law functions of volume fractions, while the role of interparticle attractions can be accounted for by expressing these rheological properties as (/g-1n, where g captures the strength of particle interaction and n the microstructure.The scaling variable (p/pc-1, suggested in percolation theory to describe rheological behavior near percolation transition, acts to collapse G’ data suggesting that along lines of constant (/g-1 these gels are rheologically identical.

  16. High fluence laser irradiation induces reactive oxygen species generation in human lung adenocarcinoma cells

    Science.gov (United States)

    Wang, Fang; Xing, Da; Chen, Tong-Sheng

    2006-09-01

    Low-power laser irradiation (LPLI) has been used for therapies such as curing spinal cord injury, healing wound et al. Yet, the mechanism of LPLI remains unclear. Our previous study showed that low fluences laser irradiation induces human lung adenocarcinoma cells (ASTC-a-1) proliferation, but high fluences induced apoptosis and caspase-3 activation. In order to study the mechanism of apoptosis induced by high fluences LPLI further, we have measured the dynamics of generation of reactive oxygen species (ROS) using H IIDCFDA fluorescence probes during this process. ASTC-a-1 cells apoptosis was induced by He-Ne laser irradiation at high fluence of 120J/cm2. A confocal laser scanning microscope was used to perform fluorescence imaging. The results demonstrated that high fluence LPLI induced the increase of mitochondria ROS. Our studies contribute to clarify the biological mechanism of high fluence LPLI-induced cell apoptosis.

  17. Influence of ethanol on swelling and release behaviors of Carbopol(®)-based tablets.

    Science.gov (United States)

    Rahim, Safwan Abdel; Al-Ghazawi, Mutasim; Al-Zoubi, Nizar

    2013-01-01

    The aim of this work was to investigate the effect of ethanol on the in vitro swelling and release behaviors of Carbopol(®)-based tablets. The swelling behavior of drug-free compacts and the release of model drugs (metformin HCl, caffeine and theophylline) from matrix tablets were evaluated in acidic and buffered media with 0, 20 and 40% (v/v) ethanol. Release data were analyzed by fitting to Higuchi and Peppas models and calculation of similarity factor (f2). ANOVA tests were performed to determine significant factors on swelling and release. It was found that ethanol affects swelling and erosion of drug-free Carbopol(®) compacts, and the effect was highly dependent on medium pH. For matrix tablets, no dose dumping due to ethanol was manifested. The release rate and mechanism, however, were significantly affected by ethanol concentration as indicated by ANOVA applied to the constant, KH, from Higuchi model and the exponent, n, from Peppas model, respectively. The effect of ethanol on release was further confirmed by similarity factor results, which indicated that ethanol led to different release profiles (f2 < 50) in seven of eight cases for matrices containing metformin HCl and in three of eight cases for matrices containing caffeine and theophylline.

  18. Thermal stability, swelling behavior and CO 2 absorption properties of Nanoscale Ionic Materials (NIMs)

    KAUST Repository

    Andrew Lin, Kun-Yi

    2014-11-11

    © The Royal Society of Chemistry 2015. Nanoscale Ionic Materials (NIMs) consist of a nanoscale core, a corona of charged brushes tethered on the surface of the core, and a canopy of the oppositely charged species linked to the corona. Unlike conventional polymeric nanocomposites, NIMs can display liquid-like behavior in the absence of solvents, have a negligible vapor pressure and exhibit unique solvation properties. These features enable NIMs to be a promising CO2 capture material. To optimize NIMs for CO2 capture, their structure-property relationships were examined by investigating the roles of the canopy and the core in their thermal stability, and thermally- and CO2-induced swelling behaviors. NIMs with different canopy sizes and core fractions were synthesized and their thermal stability as well as thermally- and CO2-induced swelling behaviors were determined using thermogravimetry, and ATR FT-IR and Raman spectroscopies. It was found that the ionic bonds between the canopy and the corona, as well as covalent bonds between the corona and the core significantly improved the thermal stability compared to pure polymer and polymer/nanofiller mixtures. A smaller canopy size and a larger core fraction led to a greater enhancement in thermal stability. This thermal stability enhancement was responsible for the long-term thermal stability of NIMs over 100 temperature swing cycles. Owing to their ordered structure, NIMs swelled less when heated or when they adsorbed CO2 compared to their corresponding polymers. This journal is

  19. Irradiation Programs and Test Plans to Assess High-Fluence Irradiation Assisted Stress Corrosion Cracking Susceptibility.

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, Sebastien [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    . Irradiation assisted stress corrosion cracking (IASCC) is a known issue in current reactors. In a 60 year lifetime, reactor core internals may experience fluence levels up to 15 dpa for boiling water reactors (BWR) and 100+ dpa for pressurized water reactors (PWR). To support a safe operation of our fleet of reactors and maintain their economic viability it is important to be able to predict any evolution of material behaviors as reactors age and therefore fluence accumulated by reactor core component increases. For PWR reactors, the difficulty to predict high fluence behavior comes from the fact that there is not a consensus of the mechanism of IASCC and that little data is available. It is however possible to use the current state of knowledge on the evolution of irradiated microstructure and on the processes that influences IASCC to emit hypotheses. This report identifies several potential changes in microstructure and proposes to identify their potential impact of IASCC. The susceptibility of a component to high fluence IASCC is considered to not only depends on the intrinsic IASCC susceptibility of the component due to radiation effects on the material but to also be related to the evolution of the loading history of the material and interaction with the environment as total fluence increases. Single variation type experiments are proposed to be performed with materials that are representative of PWR condition and with materials irradiated in other conditions. To address the lack of IASCC propagation and initiation data generated with material irradiated in PWR condition, it is proposed to investigate the effect of spectrum and flux rate on the evolution of microstructure. A long term irradiation, aimed to generate a well-controlled irradiation history on a set on selected materials is also proposed for consideration. For BWR, the study of available data permitted to identify an area of concern for long term performance of component. The efficiency of

  20. A study on the swelling behavior of poly(acrylic acid) hydrogels obtained by electron beam crosslinking

    Energy Technology Data Exchange (ETDEWEB)

    Sheikh, N., E-mail: nasheikh@aeoi.org.i [Radiation Applications Research School, Nuclear Science and Technology Research Institute, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of); Jalili, L. [Polymer group, Technology and Engineering Department, Yazd University, Yazd (Iran, Islamic Republic of); Anvari, F. [Radiation Applications Research School, Nuclear Science and Technology Research Institute, Yazd (Iran, Islamic Republic of)

    2010-06-15

    Poly(acrylic acid) (PAA) hydrogels were prepared by using electron beam (EB) crosslinking of PAA homopolymer from its aqueous solutions. The swelling behavior of the hydrogels was studied as a function of the concentration of PAA solution, radiation dose, pH of the swelling medium and swelling time. Also the environmental pH effect on the water diffusion mode into hydrogels was investigated. These hydrogels clearly showed pH-sensitive swelling behavior with Fickian type of diffusion in the stomach-like pH medium (pH 1.3) and non-Fickian type in the intestine-like pH medium (pH 6.8).

  1. Swelling-shrinking behavior of a polyampholyte gel composed of positively charged networks with immobilized polyanions.

    Science.gov (United States)

    Ogawa, Yukiko; Ogawa, Kazuyoshi; Kokufuta, Etsuo

    2004-03-30

    Polyampholyte gels were prepared by free radical polymerization of aqueous monomer solutions with the following composition: 69% N-isopropylacrylamide (thermosensitive neutral monomer), 1% N,N'-methylenebisacrylamide (cross-linker), 15% 1-vinylimidazole (cationic monomer), and either 15% acrylic acid (AAc, anionic monomer) or poly(acrylic acid) (PAAc, polyanion). We thus obtained two sorts of polyampholyte gels; that is, G1 with immobilized PAAc and G2 with randomly copolymerized AAc. The equilibrium swelling ratio (Qe) was studied as a function of the pH, NaCl concentration, and temperature. Also studied was the kinetics of swelling and shrinking in response to a sudden pH change. The significant results obtained were as follows: (i) A fully collapsed state was observed at pH 4.5-9.0 for G1 and at pH 4.5-7.0 for G2. (ii) Below and above these pH ranges, both gels were in a swollen state; therefore, an isoelectric point (pI) appeared in a wide pH range. (iii) At alkaline pH regions where a hysteresis was observed in the Qe versus pH curves of G1 and G2 as the pH was first increased then decreased, G1 exhibited very slow swelling-shrinking kinetics. (iv) An increase in the NaCl concentration allowed the gel to swell at pH approximately pI (antipolyelectrolyte behavior) but to shrink at pHs below and above the pI range (polyelectrolyte behavior). (v) The magnitude of the salt-induced shrinking of G1 is smaller than that of G2 at pH 10 and at NaCl concentrations > 0.01 M. (vi) At pH 10, an increase in the temperature from 35 to 50 degrees C led to a shrinking change of G1 but not of G2. These results were found to be explicable in terms of a different distribution of negative charges within the polyampholyte gel network.

  2. Assessment of the Efficiency of HWCon IASCC Crack Growth Rate for High Fluence BWRMaterials

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, Sebastien Paul [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    This report describes the experimental study performed to assess the efficiency of hydrogen water chemistry on the propagation rate of cracks generated by irradiation assisted stress corrosion cracking in high fluence material. The selection of the material and the test procedures followed for this study are presented. The test results obtained with 8.6 dpa specimen are discussed.

  3. Low-intensity red and infrared laser effects at high fluences on Escherichia coli cultures

    Energy Technology Data Exchange (ETDEWEB)

    Barboza, L.L.; Campos, V.M.A.; Magalhaes, L.A.G. [Instituto de Biologia Roberto Alcantara Gomes, Rio de Janeiro, RJ (Brazil). Departamento de Biofisica e Biometria; Paoli, F. [Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, MG (Brazil). Departamento de Morfologia; Fonseca, A.S., E-mail: adnfonseca@ig.com.br [Universidade Federal do Estado do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Departamento de Ciencias Fisiologicas

    2015-10-15

    Semiconductor laser devices are readily available and practical radiation sources providing wavelength tenability and high monochromaticity. Low-intensity red and near-infrared lasers are considered safe for use in clinical applications. However, adverse effects can occur via free radical generation, and the biological effects of these lasers from unusually high fluences or high doses have not yet been evaluated. Here, we evaluated the survival, filamentation induction and morphology of Escherichia coli cells deficient in repair of oxidative DNA lesions when exposed to low-intensity red and infrared lasers at unusually high fluences. Cultures of wild-type (AB1157), endonuclease III-deficient (JW1625-1), and endonuclease IV-deficient (JW2146-1) E. coli, in exponential and stationary growth phases, were exposed to red and infrared lasers (0, 250, 500, and 1000 J/cm{sup 2}) to evaluate their survival rates, filamentation phenotype induction and cell morphologies. The results showed that low-intensity red and infrared lasers at high fluences are lethal, induce a filamentation phenotype, and alter the morphology of the E. coli cells. Low-intensity red and infrared lasers have potential to induce adverse effects on cells, whether used at unusually high fluences, or at high doses. Hence, there is a need to reinforce the importance of accurate dosimetry in therapeutic protocols. (author)

  4. Grafting of acrylamide onto kappa-carrageenan via {gamma}-irradiation: Optimization and swelling behavior

    Energy Technology Data Exchange (ETDEWEB)

    Rezanejade Bardajee, Ghasem [Department of Chemistry, Polymer Research Laboratory, Sharif University of Technology, Azadi Ave., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of); Pourjavadi, Ali [Department of Chemistry, Polymer Research Laboratory, Sharif University of Technology, Azadi Ave., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)], E-mail: purjavad@sharif.edu; Sheikh, Nasrin [Nuclear Science and Technology Research Institute, Radiation Applications Research School, Kargar Avenue, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of); Sadegh Amini-Fazl, Mohammad [Department of Chemistry, Polymer Research Laboratory, Sharif University of Technology, Azadi Ave., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)

    2008-02-15

    The Taguchi method, a robust experimental design for optimization, was used for the synthesis of a superabsorbent hydrogel network using {gamma}-rays as an initiator, energy source and crosslinker at the same time. Nine different samples of superabsorbent hydrogels were prepared in various conditions from kappa-carrageenan ({kappa}C) and acrylamide by {gamma}-irradiation at room temperature. Considering the results of nine trials and according to analysis of variance (ANOVA), a new experimental condition with the concentrations of {kappa}C and acrylamide 1.5 g and 0.028 mol (2 g in total volume of 50 mL H{sub 2}O), respectively, as well as {gamma}-ray at the optimum total dose (7 kGy) was proposed. After preparing the desired hydrogels according to optimum condition, the swelling behavior of hydrogels in different media was investigated.

  5. Superabsorbent nanocomposite (alginate-g-PAMPS/MMT): synthesis, characterization and swelling behavior.

    Science.gov (United States)

    Yadav, Mithilesh; Rhee, Kyong Yop

    2012-09-01

    A superabsorbent composite (alginate-g-PAMPS/MMT) was prepared by graft copolymerization from alginate, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and Na+ montmorillonite (MMT) in an inert atmosphere. Effects of polymerization variables on water absorbency, including the content of Na+ montmorillonite, sodium alginate, N,N'-methylenebisacrylamide and AMPS, were studied. The introduced montmorillonite formed a loose and porous surface and improved the water absorbency of the alginate-g-PAMPS/MMT superabsorbent composite. Swelling behaviors of the superabsorbent composites in various cationic salt solutions (NaCl, CaCl2 and FeCl3) and anionic salt solutions (NaCl and Na2SO4) were also systematically investigated. The superabsorbent composite was further characterized using Fourier transform infrared spectroscopy (FTIR), rheology, thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) taking alginate-g-PAMPS as a reference. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. High fluence irradiation effect on the ion beam graft polymerization method

    Energy Technology Data Exchange (ETDEWEB)

    Taniike, Akira, E-mail: taniike@maritime.kobe-u.ac.jp; Hirooka, Yuya; Nakanishi, Noriaki; Nakamura, Raito; Furuyama, Yuichi

    2014-07-15

    Radiation graft polymerization method has been applied to make many industrial product. Ion beam graft polymerization method has been developed by Betz and many researchers, and we have also developed the method with proton whose energy is below a few MeV. Using the method, the substrate, e.g. polyethylene film, is graft-polymerized and has the graft chains near the surface. To conduct the method for some times, the structure of graft chains near the surface can be formed. When we want to produce the graft chains inside of the substrate, the graft chains near the surface are unnecessary. One of our objectives is to produce a functional polymer with a structure in the film. When the sample is irradiated in sufficiently high fluence, the sample can’t be graft-polymerized in the next irradiation. Comparing the density of radicals and the number of double bond with the degree of grafting, the reason why formation of a part not grafted in high fluence irradiation was discussed. Because the number of the double bond and the allyl radicals in PE are increased for high fluence irradiation, the number of the alkyl radical as a grafting point is decreased. Moreover, the alkyl radical is not produced in following irradiation since existence of double bond and peroxy radical.

  7. Modeling and simulation of the chemically induced swelling behavior of anionic polyelectrolyte gels by applying the theory of porous media

    Science.gov (United States)

    Leichsenring, Peter; Wallmersperger, Thomas

    2017-03-01

    Ionic hydrogels belong to the class of polyelectrolyte gels, also known as ionic gels. Their ability to swell or shrink under different environmental conditions such as change of pH, ion concentration or temperature make them promising materials for new sensoric or actuatoric devices. Numerical simulations play a crucial role for further developing hydrogel based devices. In the present contribution, a thermodynamically consistent continuum model based on the theory of porous media is derived. The governing field equations are solved on a one-dimensional domain by applying the finite element method. For the time discretization an Euler backward algorithm is implemented. The hydrogel swelling behavior is triggered by a chemical stimulus and is analyzed in space and time. Two mechanical configurations are considered: the hydrogel free swelling behavior and a mechanically clamped configuration, where the hydrogel swelling is hindered, are evaluated in detail. The presented results lead to a precise understanding of the chemo-electro-mechanical behavior and the driving pressure contributions.

  8. Screening of anionic-modified polymers in terms of stability, disintegration, and swelling behavior.

    Science.gov (United States)

    Laffleur, Flavia; Ijaz, Muhammad; Menzel, Claudia

    2017-11-01

    This study aimed to screen the stability, disintegration, and swelling behavior of chemically modified anionic polymers. Investigated polymers were well-known and widely used staples of the pharmaceutical and medical field, namely, alginate (AL), carboxymethyl cellulose (CMC), polycarbophil (PC), and hyaluronic acid (HA). On the basis of amide bond formation between the carboxylic acid moieties of anionic polymers and the primary amino group of the modification ligand cysteine (CYS), the modified polymers were obtained. Unmodified polymers served as controls throughout all studies. With the Ellman's assay, modification degrees were determined of synthesized polymeric excipients. Stability assay in terms of erosion study at physiological conditions were performed. Moreover, water uptake of compressed polymeric discs were evaluated and further disintegration studies according to the USP were carried out to define the potential ranking. Results ranking figured out PCCYS > CMCCYS > HACYS > ALCYS in terms of water uptake capacity compared to respective controls. Cell viability assays on Caco-2 cell line as well as on RPMI 2650 (ATTC CCL30) proved modification not being harmful to those. Due to the results of this study, an intense screening of prominent anionic polymer derivate was performed in order to help the pharmaceutical research for the best choice of polymeric excipients for developments of controlled drug release systems.

  9. Swelling and drug release behavior of poly(2-hydroxyethyl methacrylate/itaconic acid) copolymeric hydrogels obtained by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tomic, S.Lj. [Faculty of Technology and Metallurgy, Karnegijeva 4/V, Belgrade (Serbia and Montenegro); Micic, M.M. [Vinca Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia and Montenegro); Filipovic, J.M. [Faculty of Technology and Metallurgy, Karnegijeva 4/V, Belgrade (Serbia and Montenegro); Suljovrujic, E.H. [Vinca Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia and Montenegro)]. E-mail: edin@vin.bg.ac.yu

    2007-05-15

    The new copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were prepared by gamma irradiation, in order to examine the potential use of these hydrogels in controlled drug release systems. The influence of IA content in the gel on the swelling characteristics and the releasing behavior of hydrogels, and the effect of different drugs, theophylline (TPH) and fenethylline hydrochloride (FE), on the releasing behavior of P(HEMA/IA) matrix were investigated in vitro. The diffusion exponents for swelling and drug release indicate that the mechanisms of buffer uptake and drug release are governed by Fickian diffusion. The swelling kinetics and, therefore, the release rate depends on the matrix swelling degree. The drug release was faster for copolymeric hydrogels with a higher content of itaconic acid. Furthermore, the drug release for TPH as model drug was faster due to a smaller molecular size and a weaker interaction of the TPH molecules with(in) the P(HEMA/IA) copolymeric networks.

  10. Dynamic swelling behavior of interpenetrating polymer networks in response to temperature and pH.

    Science.gov (United States)

    Slaughter, Brandon V; Blanchard, Aaron T; Maass, Katie F; Peppas, Nicholas A

    2015-06-20

    Temperature responsive hydrogels based on ionic polymers exhibit swelling transitions in aqueous solutions as a function of shifting pH and ionic strength, in addition to temperature. Applying these hydrogels to useful applications, particularly for biomedical purposes such as drug delivery and regenerative medicine, is critically dependent on understanding the hydrogel solution responses as a function of all three parameters together. In this work, interpenetrating polymer network (IPN) hydrogels of polyacrylamide and poly(acrylic acid) were formulated over a broad range of synthesis variables using a fractional factorial design, and were examined for equilibrium temperature responsive swelling in a variety of solution conditions. Due to the acidic nature of these IPN hydrogels, usable upper critical solution temperature (UCST) responses for this system occur in mildly acidic environments. Responses were characterized in terms of maximum equilibrium swelling and temperature-triggered swelling using turbidity and gravimetric measurements. Additionally, synthesis parameters critical to achieving optimal overall swelling, temperature-triggered swelling, and sigmoidal temperature transitions for this IPN system were analyzed based on the fractional factorial design used to formulate these hydrogels.

  11. Scrotal swelling

    Science.gov (United States)

    ... you need any tests. Your provider may prescribe antibiotics and pain medicines, or recommend surgery. A scrotal ultrasound may be done to find where the swelling is occurring. Alternative Names Swelling of the scrotum; Testicular enlargement Images ...

  12. Synthesis, rheological behavior and swelling properties of copolymer hydrogels based on poly(N-isopropylacrylamide with hydrophilic monomers

    Directory of Open Access Journals (Sweden)

    D. Aliouche

    2013-09-01

    Full Text Available In this study, hydrogels of poly(N-isopropylacrylamide-co-acrylamide and poly(N-isopropylacrylamide-co-acrylic acid having a thermoresponsive character were prepared by aqueous free-radical co-polymerization using the ammonium persulfate/N,N,N',N'-tetramethylethylenediamine (APS/TEMED redox-pair initiator system in the presence of N,N'-methylenebisacrylamide (MBAAm crosslinker. (NIPAAm-co-AAm and (NIPAAm-co-AAc hydrogels with different thermoresponsive properties were obtained by fixing the initial NIPAAm/AAm mole ratio and and (NIPAAm-co-AAc mole ratio to 80/20 and changing the crosslinker concentration. The copolymers were characterized with infrared spectroscopy (IR and differential scanning calorimetry (DSC techniques. The swelling response of the copolymers networks as a function of time, temperature and swelling environment has been observed to be dependent on both structural aspects of the polymers and swelling environment. The swelling has been observed to be decrease with increase in MBAAm in the copolypolymers networks. Rheological behavior was studies in oscillatory module. All copolymers have a viscoelastic behaviour. We note that the elastic modulus G' increases with increasing hydrophilic monomers.DOI: http://dx.doi.org/10.4314/bcse.v27i3.14

  13. Fluorescence spectra of Rhodamine 6G for high fluence excitation laser radiation

    CERN Document Server

    Hung, J; Olaizola, A M

    2003-01-01

    Fluorescence spectral changes of Rhodamine 6G in ethanol and glycerol solutions and deposited as a film on a silica surface have been studied using a wide range of pumping field fluence at 532 nm at room temperature. Blue shift of the fluorescence spectra and fluorescence quenching of the dye molecule in solution are observed at high excitation fluence values. Such effects are not reported for the film sample. The effects are interpreted as the result of population redistribution in the solute-solvent molecular system induced by the high fluence field and the fluence dependence of the radiationless decay mechanism.

  14. Swelling behavior of welded type 316 stainless steel and its improvement

    Science.gov (United States)

    Sawai, T.; Fukai, K.; Kodaira, T.; Nishida, T.; Nayama, M.; Hishinuma, A.

    1988-07-01

    Type 316 stainless steel was electron beam welded with titanium foil insertion. The concentration of introduced titanium in the weld metal was 0.1, 0.3 and 0.6 wt% corresponding to the inserted foil thickness of 10, 30 and 60 μm, respectively. All the weld joint showed good mechanical performance. The swelling resistance of the weld metal is effectively improved by the introduced titanium. Although inhomogeneous distribution of titanium makes it difficult to estimate the extent of the improvement quantitatively, the results suggest the applicability of this method to Ti-modified 316 stainless steel, where weld metal is already reported to show reduced swelling resistance.

  15. Synthesis, swelling behavior, and biocompatibility of novel physically cross-linked polyurethane-block-poly(glycerol methacrylate) hydrogels.

    Science.gov (United States)

    Mequanint, Kibret; Patel, Alpesh; Bezuidenhout, Deon

    2006-03-01

    Physically cross-linked novel block copolymer hydrogels with tunable hydrophilic properties for biomedical applications were synthesized by controlled radical polymerization of polyurethane macroiniferter and (2,2-dimethyl-1,3-dioxolane) methyl methacrylate. The block copolymers were converted to hydrogels by the selective hydrolysis of poly[(2,2-dimethyl-1,3-dioxolane) methyl methacrylate] block to poly(glycerol methacrylate). The block copolymerization has been monitored by monomer conversion and molecular weight increase as a function of time. It was observed that the polymerization proceeded with a characteristic "living" behavior where both monomer conversion and molecular weight increased linearly, with increasing reaction time. The resulting hydrogels were investigated for their equilibrium water content (EWC), dynamic water contact angles, swelling kinetics, thermodynamic interaction parameters, plasma protein adsorption, and platelet adhesion. Similar to our previous mechanically responsive hydrogels (Mequanint, K.; Sheardown, H. J. Biomater. Sci. Polym. Ed. 2005, 10, 1303-1318), the present results indicated that block copolymer hydrogels have excellent hydrophilicity and swelling behavior with improved modulus of elasticity. The equilibrium swelling was affected by the hydrolysis time, block length of poly(glycerol methacrylate), temperature, and the presence of soluble salts. Fibrinogen adsorption and platelet adhesion were significantly lower for the hydrogels than for the control polyurethane, whereas albumin adsorption increased for the hydrogels in proportion to the contents of poly(glycerol methacrylate). These hydrogels have potential in a number of biomedical applications such as drug delivery and scaffolds for tissue engineering.

  16. Effect of ethylene glycol dimethacrylate on swelling and on metformin hydrochloride release behavior of chemically crosslinked pH-sensitive acrylic acid-polyvinyl alcohol hydrogel

    National Research Council Canada - National Science Library

    Akhtar, Muhammad Faheem; Ranjha, Nazar Muhammad; Hanif, Muhammad

    2015-01-01

    The present work objective was to prepare and to observe the effect of ethylene glycol dimethacrylate on swelling and on drug release behavior of pH-sensitive acrylic acid-polyvinyl alcohol hydrogel...

  17. Dynamic swelling behavior of interpenetrating polymer networks in response to temperature and pH

    OpenAIRE

    Slaughter, Brandon V.; Blanchard, Aaron T.; Maass, Katie F.; Peppas, Nicholas A.

    2015-01-01

    Temperature responsive hydrogels based on ionic polymers exhibit swelling transitions in aqueous solutions as a function of shifting pH and ionic strength, in addition to temperature. Applying these hydrogels to useful applications, particularly for biomedical purposes such as drug delivery and regenerative medicine, is critically dependent on understanding the hydrogel solution responses as a function of all three parameters together. In this work, interpenetrating polymer network (IPN) hydr...

  18. Magnetic/pH-sensitive κ-carrageenan/sodium alginate hydrogel nanocomposite beads: preparation, swelling behavior, and drug delivery.

    Science.gov (United States)

    Mahdavinia, Gholam Reza; Rahmani, Zeinab; Karami, Shiva; Pourjavadi, Ali

    2014-01-01

    This work describes the preparation of magnetic and pH-sensitive beads based on κ-carrageenan and sodium alginate for use as drug-targeting carriers. Physical cross-linking using K(+)/Ca(2+) ions was applied to obtain ionic cross-linked magnetic hydrogel beads. The produced magnetite beads were thoroughly characterized by TEM, SEM/EDS, XRD, FTIR, and VSM techniques. While the water absorbency (WA) of magnetic beads was enhanced by increasing the weight ratio of κ-carrageenan, introducing magnetic nanoparticles caused a decrease in WA capacity from 15.4 to 6.3 g/g. Investigation on the swelling of the hydrogel beads in NaCl, KCl, and CaCl2 solutions revealed the disintegration of beads depending on the composition of hydrogel beads and the type of metal cations in swelling media. The swelling ratio of beads indicated pH-dependent properties with maximum water absorbing at pH 7.4. Also, it was found that the strength of pH-sensitivity of magnetic beads was low for beads with the high content of carrageenan component. The in vitro drug release studies from hydrogels exhibited significant behaviors on the subject of physiological-simulated pH values and external magnetic fields. The maximum cumulative releases obtained were 98 and 43% at pH values 7.4 and 1.2, respectively. The Introducing magnetite nanoparticles influenced the cumulative release of drug.

  19. Anisotropic swelling and mechanical behavior of composite bacterial cellulose-poly(acrylamide or acrylamide-sodium acrylate) hydrogels.

    Science.gov (United States)

    Buyanov, A L; Gofman, I V; Revel'skaya, L G; Khripunov, A K; Tkachenko, A A

    2010-01-01

    Bacterial cellulose-polyacrylamide (BC-PAAm) composite hydrogels are prepared by synthesis of PAAm networks inside the BC matrices. The behavior of these gels and of the ionic ones obtained via partial hydrolysis of BC-PAAm gels is studied under swelling and compressive deformation conditions. The dependences of the hydrogels' properties on the BC matrix preparation conditions, gel synthesis conditions and the BC content in the hydrogel compositions are studied. Two types of BC gel pellicle are used in the hydrogel synthesis, namely matrix pellicles subjected to pre-pressing (samples of series A) and those not subjected to any mechanical actions before synthesis (series B samples) containing about 99% water. The effect of anisotropic swelling of type A hydrogels is detected. The type B specimens swell isotropically. Both types of hydrogel exhibit substantial anisotropy of their mechanical properties, apparent in different shapes of compression stress-strain curves of samples cut out from the gel plates in various directions. Composite hydrogels show superb mechanical properties, including compression strength up to 10 MPa and the ability to withstand long-term cyclic stresses (up to 2000-6000 cycles) without substantial reduction of mechanical properties.

  20. Deep levels induced by high fluence proton irradiation in undoped GaAs diodes

    Energy Technology Data Exchange (ETDEWEB)

    Castaldini, A.; Cavallini, A.; Polenta, L. [Univ. of Bologna (Italy); Canali, C.; Nava, F. [Univ. of Modena (Italy); Ferrini, R.; Galli, M. [Univ. of Pavia (Italy). Dipt. di Fisica

    1998-12-31

    Semi-insulating liquid encapsulated Czochralski grown GaAs has been investigated after irradiation at high fluences of high-energy protons. Electron beam induced current observations of scanning electron microscopy evidenced a radiation stimulated ordering. An analysis has been carried out of the deep levels associated with defects as a function of the irradiation fluence, using complementary current transient spectroscopies. By increasing the irradiation fluence, the concentration of the native traps at 0.37 eV together with that of the EL2 defect significantly increases and, at the same time, two new electron traps at 0.15 eV and 0.18 eV arise and quickly increase in density.

  1. Improvement of the High Fluence Irradiation Facility at the University of Tokyo

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Kenta, E-mail: murakami@tokai.t.u-tokyo.ac.jp [Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakata-Shirane, Tokai-mura, Ibaraki 319-1188 (Japan); Iwai, Takeo, E-mail: iwai@med.id.yamagata-u.ac.jp [Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, Yamagata-shi 990-9585 (Japan); Abe, Hiroaki, E-mail: abe.hiroaki@n.t.u-tokyo.ac.jp [Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakata-Shirane, Tokai-mura, Ibaraki 319-1188 (Japan); Sekimura, Naoto, E-mail: sekimura@n.t.u-tokyo.ac.jp [Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1, Tokyo, Hongo, Bunkyo, 113-8656 (Japan)

    2016-08-15

    This paper reports the modification of the High Fluence Irradiation Facility at the University of Tokyo (HIT). The HIT facility was severely damaged during the 2011 earthquake, which occurred off the Pacific coast of Tohoku. A damaged 1.0 MV tandem Cockcroft-Walton accelerator was replaced with a 1.7 MV accelerator, which was formerly used in another campus of the university. A decision was made to maintain dual-beam irradiation capability by repairing the 3.75 MV single-ended Van de Graaff accelerator and reconstructing the related beamlines. A new beamline was connected with a 200 kV transmission electron microscope (TEM) to perform in-situ TEM observation under ion irradiation.

  2. Swelling behavior of ion exchange resins incorporated in tri-calcium silicate cement matrix: I. Chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Neji, M., E-mail: mejdi.neji@cea.fr [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif-sur-Yvette (France); Polytech Lille – LML UMR, 8107 Villeneuve d' Ascq (France); Bary, B.; Le Bescop, P. [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif-sur-Yvette (France); Burlion, N. [Polytech Lille – LML UMR, 8107 Villeneuve d' Ascq (France)

    2015-12-15

    This paper presents the first part of a theoretical and experimental work aiming at modeling the chemo-mechanical behavior of composites made up of ion exchange resins (IER) solidified in a tri-calcium silicate cement paste (C{sub 3}S). Because of ion exchange processes, the volume change of the IER may cause internal pressures leading to the degradation of the material. In this study, a predictive modeling is developed for describing the chemical behavior of such material. It is based on thermodynamic equilibria to determine the evolution of the ion exchange processes, and the potential precipitation of portlandite in the composite. In parallel, a phenomenological study has been set up to understand chemical phenomena related to the swelling mechanisms. The model created has been finally implemented in a finite elements software; the simulation of a laboratory test has been performed and the results compared to experimental data. - Highlights: • Ion exchange theory to model the swelling behavior of Ion exchange resin. • Experimental phenomenon analysis about Chemo-mechanical interaction between IER and cement paste matrix. • Chemo-Transport modeling on a composite material made with IER embedded into cement paste matrix.

  3. Swelling in commercial Fe-Cr-Ni based alloys under electron irradiation

    Science.gov (United States)

    Thomas, L. E.; Gelles, D. S.

    1982-08-01

    Electron irradiation in a 1 MeV electron microscope has been used to study the void swelling response of several commercial austenitic stainless steels and iron-nickel based superalloys. Use of the 1 MeV microscope permits direct, continuous observation of the void development during elevated-temperature irradiations at displacement rates about 10 000 times greater then those in a fast breeder reactor. The alloys examined in this work included AISI 310, RA 330, A286, M813, Nimonic PE16, Inconel 706, Inconel 718 and Incoloy 901. Both helium preinjected specimens and uninjected specimens were studied. In all of the above alloys, swelling proceeds by formation of irradiation-induced dislocations and voids, followed by growth of the voids. The swelling rates and peak swelling temperatures vary considerably with alloy composition, heat treatment and helium preinjection. Comparisons of these results with recently reported swelling data from the same alloys after high fluence neutron irradiation in the EBR-II reactor shows good qualitative agreement in most cases. Helium preinjection of the electron irradiated specimens generally produced a poorer simulation than no helium preinjection. In one or two cases where the electron and neutron irradiation results strongly disagree, the differences appear to result from differences in irradiation-induced precipitation. Although the correlations between neutron and electron irradiation results are inadequate to obtain reliable engineering data by simulation, in-reactor swelling behavior is in general qualitatively well-represented by swelling response in the 1 MeV electron microscope. Nimonic is the registered trademark of Henry Wiggin and Company, UK. Inconel and Incoloy are registered trademarks of the International Nickel Company, Inc.

  4. Joint swelling

    Science.gov (United States)

    ... or a tear in the muscle tendon or ligament. Many different types of arthritis may cause swelling, ... your heart, if possible. For example, if your ankle is swollen, lay down with pillows comfortably placed ...

  5. Facial swelling

    Science.gov (United States)

    Causes of facial swelling may include: Allergic reaction ( allergic rhinitis , hay fever, or a bee sting ) Angioedema Blood ... come into contact with something you might be allergic to? What ... difficulty breathing , hives or rash , eye redness , fever .

  6. Effect of strain on viscoelastic behavior of fresh, swelled and mineralized PVP-CMC hydrogel

    Science.gov (United States)

    Saha, Nabanita; Vyroubal, Radek; Shah, Rushita; Kitano, Takeshi; Saha, Petr

    2013-04-01

    Mineralization of calcium carbonate (CaCO3) in hydrogel matrix is one of the most interesting topics of research by material scientists for the development of bio-inspired polymeric biomaterial for biomedical applications especially for bone tissue regeneration. As per our knowledge there was no work reported about rheological properties of CaCO3 mineralized hydrogel though some works have done on mineralization of CaCO3 in various gel membranes, and also it was reported about the viscoelastic properties of Agarose, Cellulose, PVA and PVPCMC hydrogels. This paper mainly focuses about the effect of strain on viscoelastic properties of fresh, swelled and mineralized (CaCO3) PVP-CMC hydrogel. All these three types of hydrogel sustain (or keep) strictly the elastic properties when low strain (1%) is applied, but at higher strain (10%) the viscoelastic moduli (G' and G") show significant change, and the nature of these materials turned from elastic to viscous.

  7. Safety and efficacy of high fluence CO2 laser skin resurfacing with a single pass.

    Science.gov (United States)

    Khosh, M M; Larrabee, W F; Smoller, B

    1999-01-01

    Carbon dioxide (CO2) laser skin resurfacing has nearly replaced more traditional methods of superficial skin rejuvenation. Post-treatment erythema is the most common side effect of this method of skin resurfacing. Sublethal thermal damage to the dermis has been proposed as an etiology for post laser erythema. Recent developments in laser resurfacing technology have aimed at minimizing thermal damage to the dermis. To determine depth of skin ablation, extent of thermal injury, and ideal laser parameters for the FeatherTouch laser system. To assess the safety and efficacy of laser resurfacing at high energy fluences with a single pass. Laser resurfacing was performed in the preauricular skin of five patients undergoing rhytidectomy. A total of 60 sites were tested with fluences of 7 to 17 Joules/cm2. Histologic evaluation of excised skin showed maximal thermal injury to be restricted to 60 microns in the papillary dermis. The reticular dermis showed no evidence of injury. Based on these findings, laser resurfacing at 17 J/cm2 (70 watts) was performed on 30 patients (in the periorbital area, a maximum of 9 J/cm2 or 36 watts was used). Follow up ranged between 12 and 18 months. Based on histologic comparison of average and high fluence laser resurfacing, high fluence laser resurfacing did not cause added thermal damage to the reticular dermis. In the clinical group, no major complications such as scarring, scleral show, infection or ectropion were encountered. Transient hyperpigmentation was noted in three patients. Overall patient satisfaction was good to excellent. Post-treatment erythema lasted an average of 4 weeks. We conclude that CO2 laser resurfacing of the face (excluding the periorbital region) can be performed safely and effectively, with the FeatherTouch laser, at 17 J/cm2 with one pass. In our group of patients, laser resurfacing with a single pass at 17 J/cm2 caused less post-operative erythema than two or more passes at 9 J/cm2.

  8. Resveratrol Prevents High Fluence Red Light-Emitting Diode Reactive Oxygen Species-Mediated Photoinhibition of Human Skin Fibroblast Migration.

    Directory of Open Access Journals (Sweden)

    Andrew Mamalis

    Full Text Available Skin fibrosis is a significant medical problem that leads to a functional, aesthetic, and psychosocial impact on quality-of-life. Light-emitting diode-generated 633-nm red light (LED-RL is part of the visible light spectrum that is not known to cause DNA damage and is considered a safe, non-invasive, inexpensive, and portable potential alternative to ultraviolet phototherapy that may change the treatment paradigm of fibrotic skin disease.The goal of our study was to investigate the how reactive oxygen species (ROS free radicals generated by high fluence LED-RL inhibit the migration of skin fibroblasts, the main cell type involved in skin fibrosis. Fibroblast migration speed is increased in skin fibrosis, and we studied cellular migration speed of cultured human skin fibroblasts as a surrogate measure of high fluence LED-RL effect on fibroblast function. To ascertain the inhibitory role of LED-RL generated ROS on migration speed, we hypothesized that resveratrol, a potent antioxidant, could prevent the photoinhibitory effects of high fluence LED-RL on fibroblast migration speed.High fluence LED-RL generated ROS were measured by flow cytometry analysis using dihydrorhodamine (DHR. For purposes of comparison, we assessed the effects of ROS generated by hydrogen peroxide (H2O2 on fibroblast migration speed and the ability of resveratrol, a well known antioxidant, to prevent LED-RL and H2O2 generated ROS-associated changes in fibroblast migration speed. To determine whether resveratrol could prevent the high fluence LED-RL ROS-mediated photoinhibition of human skin fibroblast migration, treated cells were incubated with resveratrol at concentrations of 0.0001% and 0.001% for 24 hours, irradiated with high fluences LED-RL of 480, 640, and 800 J/cm2.High fluence LED-RL increases intracellular fibroblast ROS and decreases fibroblast migration speed. LED-RL at 480, 640 and 800 J/cm2 increased ROS levels to 132.8%, 151.0%, and 158.4% relative to matched

  9. Resveratrol Prevents High Fluence Red Light-Emitting Diode Reactive Oxygen Species-Mediated Photoinhibition of Human Skin Fibroblast Migration.

    Science.gov (United States)

    Mamalis, Andrew; Koo, Eugene; Isseroff, R Rivkah; Murphy, William; Jagdeo, Jared

    2015-01-01

    Skin fibrosis is a significant medical problem that leads to a functional, aesthetic, and psychosocial impact on quality-of-life. Light-emitting diode-generated 633-nm red light (LED-RL) is part of the visible light spectrum that is not known to cause DNA damage and is considered a safe, non-invasive, inexpensive, and portable potential alternative to ultraviolet phototherapy that may change the treatment paradigm of fibrotic skin disease. The goal of our study was to investigate the how reactive oxygen species (ROS) free radicals generated by high fluence LED-RL inhibit the migration of skin fibroblasts, the main cell type involved in skin fibrosis. Fibroblast migration speed is increased in skin fibrosis, and we studied cellular migration speed of cultured human skin fibroblasts as a surrogate measure of high fluence LED-RL effect on fibroblast function. To ascertain the inhibitory role of LED-RL generated ROS on migration speed, we hypothesized that resveratrol, a potent antioxidant, could prevent the photoinhibitory effects of high fluence LED-RL on fibroblast migration speed. High fluence LED-RL generated ROS were measured by flow cytometry analysis using dihydrorhodamine (DHR). For purposes of comparison, we assessed the effects of ROS generated by hydrogen peroxide (H2O2) on fibroblast migration speed and the ability of resveratrol, a well known antioxidant, to prevent LED-RL and H2O2 generated ROS-associated changes in fibroblast migration speed. To determine whether resveratrol could prevent the high fluence LED-RL ROS-mediated photoinhibition of human skin fibroblast migration, treated cells were incubated with resveratrol at concentrations of 0.0001% and 0.001% for 24 hours, irradiated with high fluences LED-RL of 480, 640, and 800 J/cm2. High fluence LED-RL increases intracellular fibroblast ROS and decreases fibroblast migration speed. LED-RL at 480, 640 and 800 J/cm2 increased ROS levels to 132.8%, 151.0%, and 158.4% relative to matched controls

  10. Effect of multivalent ions on the swelling and mechanical behavior of superabsorbent polymers (SAPs) for mitigation of mortar autogenous shrinkage

    Science.gov (United States)

    Zhu, Qian

    The chemical and physical structure-property relationships of model superabsorbent polymer (SAP) hydrogels were characterized with respect to swelling behavior and mechanical properties in different ionic solutions (Na+, Ca2+, and Al3+). The model hydrogels were composed of poly(sodium acrylate-acrylamide) (PANa-PAM) copolymer with varying concentrations of PANa (0, 17, 33, 67, and 83 wt.%) and covalent crosslinking densities of 1, 1.5, and 2 wt.%. By synthesizing the hydrogels in-house, systems with independently tunable amounts of covalent crosslinking and anionic functional groups were created, allowing for the relative effects of covalent and ionic crosslinking on the properties of the hydrogels to be directly quantified. It was found that the presence of Ca2+ and Al3+ in the absorbed fluid significantly decreased the swelling capacity and altered the swelling kinetics of the PANa-PAM hydrogels. The presence of Al 3+ in solution resulted in the unexpected formation of a mechanically stiff barrier layer at the hydrogel's surface, which hindered the release of fluid and caused the overall elastic modulus of the hydrogel to increase from O(10 kPa) for hydrogels immersed in Ca2+ solutions to O(100 kPa) for hydrogels immersed in Al3+ solutions. Tensile tests performed on isolated specimens of the stiff barrier layer yielded elastic moduli in the O(50-100 MPa) range. Further experiments proved that PANa-PAM hydrogels are effective to keep mortar internal relative humidity at high value (~98%) during setting and also PANa-PAM decreased the autogenous shrinkage of mortar to less than 50 microstrain while plain mortar showed 350 microstrain.

  11. Plasma instability control toward high fluence, high energy x-ray continuum source

    Science.gov (United States)

    Poole, Patrick; Kirkwood, Robert; Wilks, Scott; Blue, Brent

    2017-10-01

    X-ray source development at Omega and NIF seeks to produce powerful radiation with high conversion efficiency for material effects studies in extreme fluence environments. While current K-shell emission sources can achieve tens of kJ on NIF up to 22 keV, the conversion efficiency drops rapidly for higher Z K-alpha energies. Pulsed power devices are efficient generators of MeV bremsstrahlung x-rays but are unable to produce lower energy photons in isolation, and so a capability gap exists for high fluence x-rays in the 30 - 100 keV range. A continuum source under development utilizes instabilities like Stimulated Raman Scattering (SRS) to generate plasma waves that accelerate electrons into high-Z converter walls. Optimizing instabilities using existing knowledge on their elimination will allow sufficiently hot and high yield electron distributions to create a superior bremsstrahlung x-ray source. An Omega experiment has been performed to investigate the optimization of SRS and high energy x-rays using Au hohlraums with parylene inner lining and foam fills, producing 10× greater x-ray yield at 50 keV than conventional direct drive experiments on the facility. Experiment and simulation details on this campaign will be presented. This work was performed under the auspices of the US DoE by LLNL under Contract No. DE-AC52-07NA27344.

  12. Ultra High Fluence Radiation Monitoring Technology for the Future Circular Collider at CERN

    CERN Document Server

    Gorine, Georgi; Mandic, Igor; Jazbec, Anže; Snoj, Luka; Capeans, Mar; Moll, Michael; Bouvet, Didier; Ravotti, Federico; Sallese, Jean-Michel

    2018-01-01

    The Future Circular Collider (FCC) is foreseen as the next generation ~100 km long synchrotron to be built in the Geneva area starting 2050. This machine is expected to reach an energy level of 100 TeV generating unprecedented radiation levels >100 times higher than in today`s Large Hadron Collider (LHC). Current Radiation Monitoring system, like the RADMONs employed in the LHC, will not be capable to function and withstand this harsh environment. The development of a new Ultra High Fluence and Dose Radiation Sensor is a key element to allow irradiation tests of FCC equipment and, at a later stage, to monitor radiation levels in the FCC itself. In this paper, we present an innovative dosimetry solution based on thin layers of metals, which resistivity is shown to increase significantly due to the accumulated displacement damage. After describing the fabrication techniques used to manufacture these Radiation Dependent Resistors (RDR), we show and discuss the results of the irradiation experiments carried out ...

  13. High fluence light emitting diode-generated red light modulates characteristics associated with skin fibrosis.

    Science.gov (United States)

    Mamalis, Andrew; Koo, Eugene; Garcha, Manveer; Murphy, William J; Isseroff, R Rivkah; Jagdeo, Jared

    2016-12-01

    Skin fibrosis, often referred to as skin scarring, is a significant international health problem with limited treatment options. The hallmarks of skin fibrosis are increased fibroblast proliferation, collagen production, and migration speed. Recently published clinical observations indicate that visible red light may improve skin fibrosis. In this study we hypothesize that high-fluence light-emitting diode-generated red light (HF-LED-RL) modulates the key cellular features of skin fibrosis by decreasing cellular proliferation, collagen production, and migration speed of human skin fibroblasts. Herein, we demonstrate that HF-LED-RL increases reactive oxygen species (ROS) generation for up to 4 hours, inhibits fibroblast proliferation without increasing apoptosis, inhibits collagen production, and inhibits migration speed through modulation of the phosphoinositide 3-kinase (PI3K)/Akt pathway. We demonstrate that HF-LED-RL is capable of inhibiting the unifying cellular processes involved in skin fibrosis including fibroblast proliferation, collagen production, and migration speed. These findings suggest that HF-LED-RL may represent a new approach to treat skin fibrosis. LED advantages include low cost, portability, and ease of use. Further characterizing the photobiomodulatory effects of HF-LED-RL on fibroblasts and investigating the anti-fibrotic effects of HF-LED-RL in human subjects may provide new insight into the utility of this therapeutic approach for skin fibrosis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Synthesis and swelling behaviors of carboxymethyl cellulose-based superabsorbent resin hybridized with graphene oxide.

    Science.gov (United States)

    Wang, Zhimin; Ning, Aimin; Xie, Puhui; Gao, Guangqin; Xie, Lixia; Li, Xin; Song, Andong

    2017-02-10

    Well-dispersed graphene oxide sheets were successfully incorporated into a superabsorbent resin through in situ graft polymerization of acrylic acid on carboxymethyl cellulose backbone in the presence of graphene oxide as filler. The structure and properties of the resultant superabsorbent resin were studied in detail by means of a variety of characterization methods. The influence of the feed ratio of starting materials (such as GO, initiator, cross-linker, the ratio of CMC to AA and the neutralized degree of AA) and pH values on water absorbency and retention ability was extensively determined and discussed. The obtained results showed that the introduction of graphene oxide had no obvious influence on the inherent structure of the superabsorbent resin but changed the surface morphology significantly. Importantly, the hybrid superabsorbent resin showed an enhanced thermal stability and remarkably improved swelling ratio as well as water-retention ability comparing with that of the pure superabsorbent resin. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. High fluence low-power laser irradiation induces mitochondrial permeability transition mediated by reactive oxygen species.

    Science.gov (United States)

    Wu, Shengnan; Xing, Da; Gao, Xuejuan; Chen, Wei R

    2009-03-01

    High fluence low-power laser irradiation (HF-LPLI) can induce cell apoptosis via the mitochondria/caspase-3 pathway. Here, we further investigated the mechanism involved in the apoptotic process in human lung adenocarcinoma cells (ASTC-a-1) at a laser irradiation fluence of 120 J/cm(2) (633 nm). Cytochrome c release was ascribed to mitochondrial permeability transition (MPT) because the release was prevented by cyclosporine (CsA), a specific inhibitor of MPT. Furthermore, mitochondrial permeability for calcein (approximately 620 Da) was another evidence for the MPT induction under HF-LPLI treatment. A high-level intracellular reactive oxygen species (ROS) generation was observed after irradiation. The photodynamically produced ROS caused onset of MPT, as the ROS scavenger docosahexaenoic acid (DHA) prevented the MPT. However, CsA failed to prevented cell death induced by HF-LPLI, indicating the existence of other signaling pathways. Following laser irradiation, Bax activation occurred after mitochondrial depolarization and cytochrome c release, indicating Bax activation was a downstream event. In the presence of CsA, Bax was still activated at the end-stage of apoptotic process caused by HF-LPLI, suggesting that Bax was involved in an alternative-signaling pathway, which was independent of MPT. Under HF-LPLI treatment, cell viabilities due to pre-treatment with DHA, CsA, or Bax small interfering RNA (siRNA) demonstrated that the MPT signaling pathway was dominant, while Bax signaling pathway was secondary, and more importantly ROS mediated both pathways. Taken together, these results showed that HF-LPLI induced cell apoptosis via the CsA-sensitive MPT, which was ROS-dependent. Furthermore, there existed a secondary signaling pathway through Bax activation. The observed link between MPT and triggering ROS could be a fundamental phenomenon in HF-LPLI-induced cell apoptosis.

  16. Swelling behavior of ion exchange resins incorporated in tri-calcium silicate cement matrix: II. Mechanical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Neji, M., E-mail: mejdi.neji@cea.fr [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif-sur-Yvette (France); Polytech Lille, LML UMR, 8107 Villeneuve d' Ascq (France); Bary, B.; Le Bescop, P. [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif-sur-Yvette (France); Burlion, N. [Polytech Lille, LML UMR, 8107 Villeneuve d' Ascq (France)

    2015-12-15

    This paper presents the second part of a study aiming at modelling the mechanical behavior of composites made up of ion exchange resins (IER) solidified in a tri-calcium silicate cement paste (C{sub 3}S). Such composites may be subjected to internal pressures due to ion exchange processes between ionic species which are in IER and interstitial solution of the cement paste. The reactive transport model developed in the companion paper is coupled in this study to a multi-scale approach describing the mechanical behavior of the material. It is based on an analogy with thermomechanics for taking in account the IER internal pressures, and on Eshelby-based homogenization techniques to estimate both mechanical and coupling parameters. A laboratory test has been set up to measure the macroscopic strain caused by the swelling phenomenon. The model has been finally implemented in a finite elements software. The simulation of the laboratory tests has been performed and the results have been analyzed and compared to experimental data. - Highlights: • Experimental analysis about mechanical behavior of a composite material. • Chemo-Mechanical-Transport modeling on a composite material made up with IER embedded into cement paste matrix. • Multi-scale modeling.

  17. Review of current indications for combined very high fluence collagen cross-linking and laser in situ keratomileusis surgery

    Directory of Open Access Journals (Sweden)

    Anastasios John Kanellopoulos

    2013-01-01

    Full Text Available In this brief review we will discuss the reasoning and evolution of our current use of combined very high-fluence collagen crosslinking and laser in situ keratomileusis. Several presentations and pertinent publications are reviewed, along with the key steps of the enhanced LASIK procedure. Long term outcome data support the safety and efficacy of LASIK Xtra in stabilizing myopic but also hyperopic LASIK results.In conclusion, we have compelling evidence that LASIK Xtra is a safe and effective adjunct.

  18. In vitro dynamic swelling behaviors of radiation synthesized polyacrylamide with crosslinkers in the simulated physiological body fluids

    Energy Technology Data Exchange (ETDEWEB)

    Saraydin, Dursun E-mail: saraydin@cumhuriyet.edu.tr; Isikver, Yasemin; Karadag, Erdener; Sahiner, Nurettin; Gueven, Olgun

    2002-03-01

    Acrylamide hydrogels, containing different amounts and types of crosslinkers, were synthesized via {gamma}-irradiation technique. Their swellings in simulated body fluids, such as physiological saline (0.89% NaCl) isoosmotic phosphate buffer at pH 7.4, gastric fluid at pH 1.1 (glycine-HCl), protein (aqueous solution of bovine serum albumin), urine (aqueous solution of urea), glucose and distilled water, were studied. Equilibrium swellings of the hydrogels were changed in the range 27-85 depending upon the fluids, type and amount of crosslinkers. The diffusion exponents were found over half for all hydrogels.

  19. In vitro dynamic swelling behaviors of radiation synthesized polyacrylamide with crosslinkers in the simulated physiological body fluids

    Science.gov (United States)

    Saraydın, Dursun; Işıkver, Yasemin; Karadağ, Erdener; Sahiner, Nurettin; Güven, Olgun

    2002-03-01

    Acrylamide hydrogels, containing different amounts and types of crosslinkers, were synthesized via γ-irradiation technique. Their swellings in simulated body fluids, such as physiological saline (0.89% NaCl) isoosmotic phosphate buffer at pH 7.4, gastric fluid at pH 1.1 (glycine-HCl), protein (aqueous solution of bovine serum albumin), urine (aqueous solution of urea), glucose and distilled water, were studied. Equilibrium swellings of the hydrogels were changed in the range 27-85 depending upon the fluids, type and amount of crosslinkers. The diffusion exponents were found over half for all hydrogels.

  20. Defect-free network formation and swelling behavior in ionic liquid-based electrolytes of tetra-arm polymers synthesized using a Michael addition reaction.

    Science.gov (United States)

    Yoshitake, Mari; Kamiyama, Yuji; Nishi, Kengo; Yoshimoto, Nobuko; Morita, Masayuki; Sakai, Takamasa; Fujii, Kenta

    2017-11-01

    The gelation mechanism of tetra-arm poly(ethylene glycol) (TetraPEG) prepolymers via a Michael addition reaction was investigated from the viewpoint of chemical reaction kinetics. The polymer network was formed by mixing two different TetraPEGs functionalized with maleimide and thiol terminal groups (TetraPEG-MA and TetraPEG-SH) in aqueous solutions, and the gelation rate was strongly dependent on the solution pH. We found that the gelation reaction can be a second-order reaction when the acid-base equilibrium of the terminal SH groups (-SH ⇆ -S(-) + H(+)) was taken into account, resulting in a quantitative estimation of the rate constant (kgel) in the current polymer solution system. Based on the kgel value, the network connectivity (p), which corresponds to efficiency at the linking point, was evaluated to be p > 95% at the end of the reaction; thus, the resulting TetraPEG hydrogels have a homogeneous polymer network without network defects. We used the TetraPEG network as a polymer matrix in a lithium-ion battery gel electrolyte: dried TetraPEG gels were swollen with ionic liquid-based electrolytes containing Li salts to prepare TetraPEG ion gel electrolytes. Swelling behaviors of the TetraPEG network were characterized from the swelling rate and the equilibrium swelling ratio, and we found that these swelling behaviors were significantly affected by the Li-ion component. We concluded that an intermolecular interaction between Li-ions and the polymer (Li-ion coordination with the O atoms within the PEG chains) plays a key role in the fundamental physical properties of the gel electrolyte.

  1. Modeling of Radiation Damage Effects in Silicon Detectors at High Fluences HL-LHC with Sentaurus TCAD

    CERN Document Server

    Passeri, D.; Morozzi, A.; Bilei, G.M.

    2016-01-01

    In this work we propose the application of an enhanced radiation damage model based on the introduction of deep level traps / recombination centers suitable for device level numerical simulation of silicon detectors at very high fluences (e.g. 2.0 1016 1MeV equivalent neutrons/cm2). We present the comparison between simulation results and experimental data for p-type substrate structures in dierent operating conditions (temperature and biasing voltages) for fluences up to 2.2 1016 neutrons/cm2. The good agreement between simulation findings and experimental measurements fosters the application of this modeling scheme to the optimization of the next silicon detectors to be used at HL-LHC.

  2. Mechanism study on mitochondrial fragmentation under oxidative stress caused by high-fluence low-power laser irradiation

    Science.gov (United States)

    Wu, Shengnan; Zhou, Feifan; Xing, Da

    2012-03-01

    Mitochondria are dynamic organelles that undergo continual fusion and fission to maintain their morphology and functions, but the mechanism involved is still not clear. Here, we investigated the effect of mitochondrial oxidative stress triggered by high-fluence low-power laser irradiation (HF-LPLI) on mitochondrial dynamics in human lung adenocarcinoma cells (ASTC-a-1). Upon HF-LPLI-triggered oxidative stress, mitochondria displayed a fragmented structure, which was abolished by exposure to dehydroascorbic acid (DHA), a reactive oxygen species scavenger, indicating that oxidative stress can induce mitochondrial fragmentation. Mitochondrial translocation of the profission protein dynamin-related protein 1 (Drp1) was observed following HF-LPLI, demonstrating apoptosis-related activation of Drp1. Notably, DHA pre-treatment prevented HF-LPLI-induced Drp1 activation. We conclude that mitochondrial oxidative stress through activation of Drp1 causes mitochondrial fragmentation.

  3. Combined Bulk and Surface Radiation Damage Effects at Very High Fluences in Silicon Detectors: Measurements and TCAD Simulations

    CERN Document Server

    Moscatelli, F; Morozzi, A; Mendicino, R; Dalla Betta, G F; Bilei, G M

    2016-01-01

    In this work we propose a new combined TCAD radiation damage modelling scheme, featuring both bulk and surface radiation damage effects, for the analysis of silicon detectors aimed at the High Luminosity LHC. In particular, a surface damage model has been developed by introducing the relevant parameters (NOX, NIT) extracted from experimental measurements carried out on p-type substrate test structures after gamma irradiations at doses in the range 10-500 Mrad(Si). An extended bulk model, by considering impact ionization and deep-level cross-sections variation, was included as well. The model has been validated through the comparison of the simulation findings with experimental measurements carried out at very high fluences (2×1016 1 MeV equivalent n/cm2) thus fostering the application of this TCAD approach for the design and optimization of the new generation of silicon detectors to be used in future HEP experiments.

  4. Synthesis, characterization, and swelling behaviors of salt-sensitive maize bran-poly(acrylic acid) superabsorbent hydrogel.

    Science.gov (United States)

    Zhang, Mingyue; Cheng, Zhiqiang; Zhao, Tianqi; Liu, Mengzhu; Hu, Meijuan; Li, Junfeng

    2014-09-03

    A novel composite hydrogel was prepared via UV irradiation copolymerization of acrylic acid and maize bran (MB) in the presence of composite initiator (2,2-dimethoxy-2-phenylacetophenone and ammonium persulfate) and cross-linker (N,N'-methylenebis(acrylamide)). Under the optimized conditions, maize bran-poly(acrylic acid) was obtained (2507 g g(-1) in distilled water and 658 g g(-1) in 0.9 wt % NaCl solution). Effects of granularity, salt concentration, and various cations and anions on water absorbency were investigated. It was found that swelling was extremely sensitive to the ionic strength and cation and anion type. Swelling kinetics and water diffusion mechanism in distilled water were also discussed. Moreover, the product showed excellent water retention capability under the condition of high temperature or high pressure. The salt sensitivity, good water absorbency, and excellent water retention capability of the hydrogels give this intelligentized polymer wide potential applications.

  5. Structural Parameters and Swelling Behavior of pH Sensitive Poly(acrylamide-co-acrylic acid) Hydrogels

    OpenAIRE

    Thakur, A.; Wanchoo, R. K.; Singh, P

    2011-01-01

    In the present work, hydrogels based on acrylamide (AAm) and acrylic acid (AAc), crosslinked with N,N’-methylenebisacrylamide (MBAAm) were prepared by free radical polymerization in solution. The effect of initial AAm/AAc mole ratio and nominal crosslinking ratio (moles of crosslinking agent/moles of polymer repeat unit) on the dynamic and equilibrium swelling behaviour of hydrogels was investigated. Hydrogels were characterized by the polymer volume fraction in the swollen state (ν2,s ), the...

  6. Synthesis, characterization, swelling and drug release behavior of semi-interpenetrating network hydrogels of sodium alginate and polyacrylamide.

    Science.gov (United States)

    Samanta, Himadri Sekhar; Ray, Samit Kumar

    2014-01-01

    Several semi interpenetrating network (SIPN) type hydrogels were synthesized by in-situ free radical crosslink copolymerization of acrylamide and crosslinker N,N'-methylene bisacrylamide (MBA) in aqueous solution of sodium alginate (SA).These SIPN hydrogels were characterized by FTIR, NMR SEM, DTA-TGA, XRD, PZC and also by swelling characteristics and network parameters. Adsorption (loading) and release of acetaminophen drug were studied with these hydrogels. Solution pH, crosslinker concentration and monomer to SA weight ratio of the hydrogels were found to have a strong effect on adsorption and in vitro release profile of the drug from the gel matrix. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Swelling Behavior of High-Chromium, Vanadium-Bearing Titanomagnetite Pellets in H2-CO-CO2 Gas Mixtures

    Science.gov (United States)

    Li, F.; Chu, M. S.; Tang, J.; Liu, Z. G.; Feng, C.; Tang, Y. T.

    2017-10-01

    In this study, the effects of temperature, gas composition and reduction degree on the reduction swelling index (RSI) of high-chromium vanadium-bearing titanomagnetite (HCVT) pellets during reduction with H2-CO-CO2 gas mixtures are investigated. The results show that the formation of massive wüstite causes most of the volume expansion of the pellets. The swelling of HCVT pellets is intensified with the temperature and content of CO, and the RSI reaches a maximum at the reduction degree of 35-50%. In H2/CO = 5/2 (volume ratio) with a temperature range from 1223 K to 1373 K, the maximum RSI increases from 14.68% to 22.54%. Nevertheless, when the ratio of H2/CO increases from 2/5 to 5/2 at 1223 K, the maximum RSI of the pellets decreases from 21.25% to 19.55%. Meanwhile, the shrinking rate of the pellets also decreases from 33.20% to 27.26%.

  8. Foot, leg, and ankle swelling

    Science.gov (United States)

    Swelling of the ankles - feet - legs; Ankle swelling; Foot swelling; Leg swelling; Edema - peripheral; Peripheral edema ... Foot, leg, and ankle swelling is common when the person also: Is overweight Has a blood clot ...

  9. Characterization of the Rheological and Swelling Properties of Synthetic Alkali Silicate Gels in Order to Predict Their Behavior in ASR Damaged Concrete

    Science.gov (United States)

    Vayghan, Asghar Gholizadeh

    Alkali-silica reaction (ASR) is a major concrete durability concern that is responsible for the deterioration of concrete infrastructure in the world. The resultant of the reaction between the cement alkali hydroxides and the metastable silicates in the aggregates is a hygroscopic and expansive alkali-silicate gel (referred to as ASR gel in this document). The swelling behavior of ASR gels determines the extent of damage to concrete structures and, as such, mitigation of ASR relies on understanding these gels and finding ways to prevent them either from formation, or from swelling after formation. This dissertation focuses on the synthesis and characterization of ASR gels with wide ranges of compositions similar to what has been reported for the filed ASR gels in the literature. The experimental work consisted of three phases as follow. Phase I: Investigation of rheology, chemistry and physics of ASR gels produced through sol-method. Inspired from the existing literature, two sol-gel methods have been developed for the synthesis of ASR gels. The rheological (primarily gelation time, yield stress, and equilibrium stress), chemical (pore solution pH, pore solution composition, osmotic pressure, solid phase composition, stoichiometry of gelation reactions) and physical (evaporable water, solid content, etc.) properties of synthetic ASR gels have been extensively investigated in this phase. Ca/Si, Na/Si and K/Si, and water content were considered as the main chemical composition variables. In order to investigate the suppressing effects of lithium on the swelling properties of ASR gels, the gels were added with lithium in a part of the experimental program. The results strongly suggested that Ca/Si has a positive effect on the yield stress of the gels and their rate of gelation. Na/Si was found to have a decreasing effect on the yield stress and gelation rate (especially at low Ca/Si levels). K/Si and Li/Si had second-order (i.e., polynomial) effects on the yield

  10. Study of hydrogel modified drilling fluid: preparation, rheological properties and swelling behaviors of Chitosan N-Isopropylacrylamide hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Tamsilian, Y.; Ramazani, S.A.A. [Sharif University of Technology, Tehran (Iran, Islamic Republic of). Dept. of Chemical and Petroleum Engineering], E-mails: ramazani@sharif.edu; tamsilian@gmail.com

    2012-04-15

    Chitosan N-Isopropylacrylamide hydrogels were synthesized by thermal and gamma radiation methods. The thermal method used an initiator and a cross linker while the gamma radiation process was done in absence of any kind of initiator or cross linker agent. The study found that the gamma radiation method produced hydrogels with higher water swelling ratio. The rheological properties of the hydrogels used in the preparation of drilling fluids were investigated. Properties such as apparent viscosity, plastic viscosity, gel strength, and yield point were compared with those of Carboxymethyl Cellulose (CMC) and Xanthenes (XC) resins, which are widely used in drilling fluids. The hydrogel synthesized by gamma radiation improved rheological properties of drilling fluids better than CMC, XC, and thermal prepared hydrogel. Also, comparison results show that whereas linear polymer effects on mud properties are more significant in low polymer concentration, prepared crosslinked hydrogel effects are more prominent at high concentrations. (author)

  11. Diamond Particle Detector Properties during High Fluence Material Damage Tests and their Future Applications for Machine Protection in the LHC

    CERN Document Server

    Burkart, F; Borburgh, J; Dehning, B; Di Castro, M; Griesmayer, E; Lechner, A; Lendaro, J; Loprete, F; Losito, R; Montesano, S; Schmidt, R; Wollmann, D; Zerlauth, M

    2013-01-01

    Experience with LHC machine protection (MP) during the last three years of operation shows that the MP systems sufficiently protect the LHC against damage in case of failures leading to beam losses with a time constant exceeding 1ms. An unexpected fast beam loss mechanism, called UFOs [1], was observed, which could potentially quench superconducting magnets. For such fast losses, but also for better understanding of slower losses, an improved understanding of the loss distribution within a bunch train is required [2]. Diamond particle detectors with bunch-by-bunch resolution and high dynamic range have been developed and successfully tested in the LHC and in experiments to quantify the damage limits of LHC components. This paper will focus on experience gained in use of diamond detectors. The properties of these detectors were measured during high-fluence material damage tests in CERN’s Hi-RadMat facility. The results will be discussed and compared to the cross-calibration with FLUKA simulations. Future app...

  12. Deep learning for evaluating difficult-to-detect incomplete repairs of high fluence laser optics at the National Ignition Facility

    Science.gov (United States)

    Mundhenk, T. Nathan; Kegelmeyer, Laura M.; Trummer, Scott K.

    2017-03-01

    Two machine-learning methods were evaluated to help automate the quality control process for mitigating damage sites on laser optics. The mitigation is a cone-like structure etched into locations on large optics that have been chipped by the high fluence (energy per unit area) laser light. Sometimes the repair leaves a difficult to detect remnant of the damage that needs to be addressed before the optic can be placed back on the beam line. We would like to be able to automatically detect these remnants. We try Deep Learning (convolutional neural networks using features autogenerated from large stores of labeled data, like ImageNet) and find it outperforms ensembles of decision trees (using custom-built features) in finding these subtle, rare, incomplete repairs of damage. We also implemented an unsupervised method for helping operators visualize where the network has spotted problems. This is done by projecting the credit for the result backwards onto the input image. This shows regions in an image most responsible for the networks decision. This can also be used to help understand the black box decisions the network is making and potentially improve the training process.

  13. Mitochondrial signaling pathway involved in cell apoptosis induced by high-fluence low-power laser irradiation

    Science.gov (United States)

    Wu, Shengnan; Xing, Da

    2011-03-01

    High fluence low-power laser irradiation (HF-LPLI) is a new stimulus to trigger cell apoptosis. Recently, great efforts have been made to investigate the mechanism involved in it. Our results show that HF-LPLI induces cell apoptosis through a large amount of intracellular reactive oxygen species (ROS), especially a higher generation in mitochondria. These triggered ROS causes mitochondrial injury manifested by mitochondrial depolarization and cytochrome c release. Caspase-3 activation is a downstream event which executed cell apoptosis finally. In addition, we exclude caspase-8/Bid signaling pathway in HF-LPLI-induced cell apoptosis. However, another important Bcl-2 pro-apoptotic member Bax participates in the apoptotic process. Our result show that Bax is activated after the diffusion of mitochondrial transmembrane potential and cytochrome c release, suggesting that Bax does not affect outer mitochondrial membrane permeabilization (OMMP). We postulate that the activation of Bax is mediated by oxidative stress caused by laser irradiation through ROS/GSK-3β/Bax pathway. Further studies need to be performed to clarify the exactly mechanism involved in HF-LPLI induced cell apoptosis.

  14. Plume splitting and oscillatory behavior in transient plasmas generated by high-fluence laser ablation in vacuum

    Science.gov (United States)

    Focsa, C.; Gurlui, S.; Nica, P.; Agop, M.; Ziskind, M.

    2017-12-01

    We present a short overview of studies performed in our research groups over the last decade on the characterization of transient plasma plumes generated by laser ablation in various temporal regimes, from nanosecond to femtosecond. New results are also presented along with this overview, both being placed in the context of similar studies performed by other investigators. Optical (fast gate intensified CCD camera imaging and space- and time-resolved emission spectroscopy) and electrical (mainly Langmuir probe) methods have been applied to experimentally explore the dynamics of the plasma plume and its constituents. Peculiar effects as plume splitting and sharpening or oscillations onset have been evidenced in vacuum at high laser fluence. New theoretical approaches have been developed to account for the experimental observations.

  15. SWELLING AND COMPRESSIBILITY CHARACTERISTICS OF SOIL - BENTONITE MIXTURES

    Directory of Open Access Journals (Sweden)

    Agus Setyo Muntohar

    2003-01-01

    Full Text Available Understanding characteristics of soil mixtures lead to increasing the confidence level before applying such materials in the field. The outcomes of this study can provide insight into the swelling and the compressibility behavior of soil – bentonite mixtures, between non-swelling materials and swelling materials. A simple swell and compression laboratory test has been conducted for the purposes of this study. The result of this study indicated that the existence of bentonite in the soil mixtures influence the swelling behavior, which follows a hyperbolic curve model. Amount and size of nonswelling fraction affected the swelling and compressibility.

  16. A novel reversible thermo-swelling hydrogel

    Directory of Open Access Journals (Sweden)

    2010-07-01

    Full Text Available A novel reversible thermo-swelling gel was prepared from poly(vinyl alcohol-trimellitate (PVA-T by crosslinking with ethylene glycol diglycidyl ether (EGDGE. Only in the presence of sulfate anion, this polymer gel showed a significant and reversible swelling behavior with increasing the temperature from 5 to 40°C, and vice versa, probably due to the scission and formation of the inter- and/or intramolecular hydrogen-bondings (HBs between the carboxyls on the side groups. The involvement of inter- and/or intramolecular HBs for the thermo-swelling behavior was also suggested by a significant dependence on HCl concentration of the swelling degree. In addition, the swelling reversibility and reproducibility were confirmed via the temperature jump between 5 and 40°C, well satisfying for a candidate as a thermosensitive material.

  17. Novel myopic refractive correction with transepithelial very high-fluence collagen cross-linking applied in a customized pattern: early clinical results of a feasibility study

    Directory of Open Access Journals (Sweden)

    Kanellopoulos AJ

    2014-04-01

    Full Text Available Anastasios John Kanellopoulos LaserVision.gr Institute, Athens, Greece, and New York Medical School, New York, NY, USA Background: The purpose of this study is to report the safety and efficacy of a new application of collagen cross-linking using a novel device to achieve predictable refractive myopic changes in virgin corneas. Methods: Four cases were treated with a novel device employing very high-fluence collagen cross-linking applied in a myopic pattern. Prior to treatment, riboflavin solution was applied to the intact epithelium. The collagen cross-linking device was then engaged for a total of 12 J/cm2, to be applied transepithelially in a predetermined pattern. Cornea clarity, corneal keratometry, and corneal topography were evaluated by both Placido disc and Scheimpflug imaging, along with cornea anterior segment optical coherence tomography and endothelial cell counts. Results: An average of 2.3 diopters was achieved in the first week in all four cases treated with the very high-fluence myopic collagen cross-linking intervention. There was a slight regression to 1.44 diopters at 1 month, which remained stable at 6-month follow-up. The mean keratometry change was from 44.90 diopters to 43.46 diopters. There was no significant change in endothelial cell counts or corneal clarity. There was some mild change in epithelial thickness distribution, with the treated area showing a slight but homogeneous reduction in mean thickness from 52 µm to 44 µm. Conclusion: This report describes the novel application of very high-fluence collagen cross-linking with a predictable well defined myopic refractive (flattening corneal effect. This technique has the advantages of essentially no postoperative morbidity, immediate visual rehabilitation, and the potential for tapering until the desired result is achieved. Keywords: myopia, refractive correction, high-fluence collagen cross-linking, clinical results

  18. Molecular thermodynamic analysis for assessing the relationship between reentrant swelling behavior and ternary liquid-liquid equilibrium for poly(N-isopropylacrylamide) nanometer-sized gel particles in a water-tetrahydrofuran cosolvent system.

    Science.gov (United States)

    Jung, Sang Chul; Bae, Young Chan

    2012-02-23

    The influence of phase separation on swelling behavior was investigated based on the thermodynamic framework of reswelling phenomena. The cloud-point for a ternary system of water(1)-tetrahydrofuran (THF)(2)-poly(N-isopropylacrylamide)(3) was examined by thermo-optical analysis (TOA). Nanometer-sized N-isopropylacrylamide (NIPA) gel particles were prepared by precipitation polymerization, and their swelling behaviors were determined using photon correlation spectroscopy (PCS). NIPA gel particles underwent reswelling when the ratio of water to THF was varied. First, the modified double lattice model (MDL) was employed to determine ternary interaction energy parameters for the liquid-liquid equilibrium (LLE) of linear poly-NIPA in a water-THF cosolvent system. The reentrant swelling equilibria of the NIPA gel in the water-THF system were then calculated using the interaction energy parameters. © 2012 American Chemical Society

  19. Safety and efficacy of low fluence, high repetition rate versus high fluence, low repetition rate 810-nm diode laser for axillary hair removal in Chinese women.

    Science.gov (United States)

    Li, Wenhai; Liu, Chengyi; Chen, Zhou; Cai, Lin; Zhou, Cheng; Xu, Qianxi; Li, Houmin; Zhang, Jianzhong

    2016-11-01

    High-fluence diode lasers with contact cooling have emerged as the gold standard to remove unwanted hair. Lowering the energy should result in less pain and could theoretically affect the efficacy of the therapy. To compare the safety and efficacy of a low fluence high repetition rate 810-nm diode laser to those of a high fluence, low repetition rate diode laser for permanent axillary hair removal in Chinese women. Ninety-two Chinese women received four axillae laser hair removal treatments at 4-week intervals using the low fluence, high repetition rate 810-nm diode laser in super hair removal (SHR) mode on one side and the high fluence, low repetition rate diode laser in hair removal (HR) mode on the other side. Hair counts were done at each follow-up visit and 6-month follow-up after the final laser treatment using a "Hi Quality Hair Analysis Program System"; the immediate pain score after each treatment session was recorded by a visual analog scale. The overall median reduction of hair was 90.2% with the 810-nm diode laser in SHR mode and 87% with the same laser in HR mode at 6-month follow-up. The median pain scores in SHR mode and in HR mode were 2.75 and 6.75, respectively. Low fluence, high repetition rate diode laser can efficiently remove unwanted hair but also significantly improve tolerability and reduce adverse events during the course of treatment.

  20. Long-term safety and efficacy of high-fluence collagen crosslinking of the vehicle cornea in Boston keratoprosthesis type 1.

    Science.gov (United States)

    Kanellopoulos, Anastasios J; Asimellis, George

    2014-09-01

    The aim of this study was to evaluate the safety and efficacy of very high-fluence collagen crosslinking (CXL) as a means of achieving increased corneal rigidity and reduced enzymatic digestion in the vehicle cornea of Boston keratoprosthesis (KPro) type 1. Eleven consecutive patients fitted with a KPro (5 with a previous repeat cornea graft failure, 4 with ocular cicatricial pemphigoid, and 2 with chemical burn) underwent donor vehicle cornea pretreatment with very high-fluence prophylactic CXL in a 2-step procedure. First, the donor cornea was crosslinked with an intrastromal riboflavin instillation through a femtosecond laser-created pocket. This was followed up with a superficial CXL treatment. On the completion of the CXL pretreatment, the cornea center was trephined with the femtosecond laser, and the KPro was fitted onto the crosslinked donor cornea. Visual acuity, corneal surface, and donor vehicle cornea stability were evaluated. Follow-up evaluations were conducted over the next 9 years with a mean of 7.5 years. Mean uncorrected visual acuity improved from light perception to 20/60. One patient required a follow-up surgery, because of significant melt in the host cornea. None of the eyes developed melts and/or infection, especially on the vehicle cornea on which the KPro was fitted. Pretreatment with intrastromal and superficial very high-fluence CXL in conjunction with Boston type 1 KPro seems to be a safe and effective adjunctive treatment for achieving increased vehicle donor cornea rigidity. Additionally, there is an increased resistance to enzymatic degradation. This application may serve to enhance the biomechanical stability and external disease resistance of the donor vehicle cornea in patients with advanced external disease.

  1. Influence of Concentration of Compatibilizer on Long- term Water Absorption and Thickness Swelling Behavior of Polypropylene, Wood Flour/Glass Fiber Hybrid Composites

    OpenAIRE

    Alireza Ghotbifar; Saeid Kazemi najafi; Rabi Behrooz ashkiki

    2011-01-01

    The influence of concentration (2, 3 and 5%) of Maleic Anhydride Grafted Polypropylene (MAPP) on long term water absorption and thickness swelling of wood flour/E-glass fiber Hybrid polypropylene composites were studied. The samples (strips with 10 mm thickness and 70 mm width) were made using a laboratory twin-screw extruder. Long term water absorption and thickness swelling kinetics of manufactured hybrid composites were evaluated by immersing them in water at room temperature for several w...

  2. High-fluence and high-density treatment of perioral rhytides using a new, fractionated 2,790-nm ablative erbium-doped Yttrium Scandium Gallium Garnet Laser.

    Science.gov (United States)

    Ciocon, David H; Hussain, Mussarat; Goldberg, David J

    2011-06-01

    In this study, we evaluated the safety and efficacy of a novel 2,790-nm erbium-doped yttrium scandium gallium garnet (Er:YSGG) laser system for the treatment of facial photodamage and perioral wrinkles using a single-treatment, high-fluence, high-density protocol. Eleven female participants with Fitzpatrick skin types II to III and facial wrinkles underwent a single full-face fractional ablative treatment with a 2,790-nm Er:YSGG laser. Follow-up visits were completed at 1, 2, and 6 weeks 3 and 6 months. Quartile improvement scale (0-4) and Fitzpatrick wrinkle scores (1-9) were used for the assessments. Based on blinded photographic assessments, the mean difference in Fitzpatrick wrinkle scores for full face wrinkles was 1.5 ± 1.2 (a reduction from 6.6 to 5.1; paired t-test, p = .003). There was also a statistically significant mean reduction of 1.7 ± 1.3 in perioral wrinkle scores (from 6.7 to 5.0; p = .002). No serious adverse events were reported. A novel, fractionated, ablative 2,790-nm Er:YSGG laser can safely and effectively treat photodamage and perioral wrinkles in a single treatment using a high-fluence, high-density protocol. Cutera provided the equipment used in this study and funding to Dr. Goldberg. © 2011 by the American Society for Dermatologic Surgery, Inc.

  3. Extracting the distribution of laser damage precursors on fused silica surfaces for 351 nm, 3 ns laser pulses at high fluences (20-150 J/cm2).

    Science.gov (United States)

    Laurence, Ted A; Bude, Jeff D; Ly, Sonny; Shen, Nan; Feit, Michael D

    2012-05-07

    Surface laser damage limits the lifetime of optics for systems guiding high fluence pulses, particularly damage in silica optics used for inertial confinement fusion-class lasers (nanosecond-scale high energy pulses at 355 nm/3.5 eV). The density of damage precursors at low fluence has been measured using large beams (1-3 cm); higher fluences cannot be measured easily since the high density of resulting damage initiation sites results in clustering. We developed automated experiments and analysis that allow us to damage test thousands of sites with small beams (10-30 µm), and automatically image the test sites to determine if laser damage occurred. We developed an analysis method that provides a rigorous connection between these small beam damage test results of damage probability versus laser pulse energy and the large beam damage results of damage precursor densities versus fluence. We find that for uncoated and coated fused silica samples, the distribution of precursors nearly flattens at very high fluences, up to 150 J/cm2, providing important constraints on the physical distribution and nature of these precursors.

  4. Treatment of café-au-lait macules with a high-fluenced 1064-nm Q-switched neodymium:yttrium aluminum garnet laser.

    Science.gov (United States)

    Kim, Jiehoon; Hur, Hoon; Kim, Yu Ri; Cho, Sung Bin

    2017-07-06

    Café-au-lait macules (CALMs) are light to dark brown macules or patches of increased melanin concentration found along the dermoepidermal junction. Although many attempts to treat CALMs using various kinds of laser/light-based devices have been reported, CALMs remain refractory thereto with high recurrence rates. In this case series, we describe four patients with idiopathic CALMs that were effectively and safely treated with a non-ablative, high-fluenced, Q-switched (QS), 1064-nm neodymium:yttrium aluminum garnet (Nd:YAG) laser. The typical laser parameters for treating CALMs, including a spot size of 7-7.5 mm, a fluence of 2.4-2.5 J/cm2, and one to two passes until the appearance of mild erythema, but not petechiae, were utilized in this study over 12-24 treatment sessions at 2-week intervals. We suggest that high-fluenced QS 1064-nm Nd:YAG laser treatment can be used as an effective and alternative treatment modality for CALMs with minimal risk of side effects.

  5. Characterization of heavy oils. 3: Prediction of gas injection behavior -- Swelling test, multicontact test, multiple-contact minimum miscibility pressure, and multiple-contact minimum miscibility enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Jaubert, J.N. [Ecole Nationale Superieure des Industries Chimiques, Nancy (France); Neau, E.; Avaullee, L. [Faculte des Sciences de Luminy, Marseille (France). Lab. de Chimie Physique; Zaborowski, G. [Compagnie Petroliere TOTAL, Saint-Remy-les-Chevreuse (France). Centre Scientifique et Technique

    1995-11-01

    The modeling of miscible gas injection into reservoir crude oils was performed using a cubic equation of state coupled with a predictive procedure for characterizing the heavy fractions. It is shown that experimental data on the swelling test, multicontact test, slim tube minimum miscibility pressure (MMP), and minimum miscibility enrichment (MME) for 10 different crude oils from different fields are satisfactorily calculated using the predictive characterization. However, in the case of MMP and MME calculations, a significant deviation may appear between predicted and experimental values. Reasons for this discrepancy are discussed. The influence of tuning the equation of state parameters in the estimation of results for the swelling test is also discussed.

  6. Multi-scale modeling of phase explosion in high fluence nanosecond laser ablation and clarification of ablation depth prediction criterion

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yunfeng; Shin, Yung C., E-mail: shin@purdue.edu

    2015-12-01

    Graphical abstract: - Highlights: • ns laser ablation of aluminum and copper with phase explosion is investigated. • Melt ejection behavior is successfully predicted through a HD/MD/SPH model. • 0.9T{sub c} does not always work for all materials for ablation depth prediction. • 0.75–0.8T{sub c} works better for copper in predicting ablation depth. - Abstract: When phase explosion occurs, accurate prediction of the ablation behavior in the high energy nanosecond laser ablation process still remains a difficult challenge. In this paper, nanosecond laser ablation of aluminum and copper with phase explosion is investigated through a multi-scale model and experimental verification. The melt ejection behavior during phase explosion is successfully predicted by combined molecular dynamics (MD) and smoothed particle hydrodynamics (SPH) simulations and validated against the experiments. The commonly adopted 0.9T{sub c} (critical temperature) criterion for phase explosion boundary is also assessed with the prediction of the ablation depth for both aluminum and copper, and it is found that the 0.9T{sub c} criterion does not always work. The multi-scale model developed in this work is shown to have better capability in predicting the ablation behavior when phase explosion is involved.

  7. Synthesis and Swelling Behavior of pH-Sensitive Semi-IPN Superabsorbent Hydrogels Based on Poly(acrylic acid) Reinforced with Cellulose Nanocrystals

    National Research Council Canada - National Science Library

    Lim Sze Lim; Noor Afizah Rosli; Ishak Ahmad; Azwan Mat Lazim; Mohd Cairul Iqbal Mohd

    2017-01-01

    .... It was found that the hydrogel reached maximum swelling at pH 7. The potential of the resulting hydrogels to act as drug carriers was then evaluated by means of the drug encapsulation efficiency test using theophylline as a model drug. It was observed that 15% CNC/PAA hydrogel showed the potential to be used as drug carrier system.

  8. Mitosis is swell.

    Science.gov (United States)

    Zatulovskiy, Evgeny; Skotheim, Jan M

    2015-11-23

    Cell volume and dry mass are typically correlated. However, in this issue, Zlotek-Zlotkiewicz et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201505056) and Son et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201505058) use new live-cell techniques to show that entry to mitosis coincides with rapid cell swelling, which is reversed before division. © 2015 Zatulovskiy and Skotheim.

  9. Spinal cord swelling and candidiasis

    Energy Technology Data Exchange (ETDEWEB)

    Ho, K.; Gronseth, G.; Aldrich, M.; Williams, A.

    1982-11-01

    Fusiform swelling of the spinal cord was noted myelographically in a patient with Hodgkin's disease. Autopsy revealed that the swelling was caused by Candida infection of the spinal cord. It is suggested that fungal infection be included in the differential diagnosis of spinal cord swelling in the immunosuppressed cancer patient.

  10. Journal of EEA, Vol. 30, 2013 PREDICTION OF SWELLING ...

    African Journals Online (AJOL)

    dell

    main reason of swelling behavior is water absorption of soil mass .... thoroughly mixed to obtain a uniform bulk sample. Individual samples ... Proposed Model. The mathematical form of the model presented by. Richard and Abbott, 1975 may be rewritten [12] to relate the percentage of swell (S) of expansive soil to time (T) as ...

  11. Swelling Characteristics and Tensile Properties of Natural Fiber ...

    African Journals Online (AJOL)

    The swelling behavior and tensile strength of natural fiber-reinforced plastic in premium motor spirit (PMS), dual purpose kerosene (DPK) and sea water have been studied. Composite formed by reinforcing polyester resin with Okam fibers was immersed in the selected solvents for 16 weeks (4 months). Swelling ...

  12. Mitochondrial Swelling Induced by Glutathione

    Science.gov (United States)

    Lehninger, Albert L.; Schneider, Marion

    1959-01-01

    Reduced glutathione, in concentrations approximating those occurring in intact rat liver, causes swelling of rat liver mitochondria in vitro which is different in kinetics and extent from that yielded by L-thyroxine. The effect is also given by cysteine, which is more active, and reduced coenzyme A, but not by L-ascorbate, cystine, or oxidized glutathione. The optimum pH is 6.5, whereas thyroxine-induced swelling is optimal at pH 7.5. The GSH-induced swelling is not inhibited by DNP or dicumarol, nor by high concentrations of sucrose, serum albumin, or polyvinylpyrrolidone, in contrast to thyroxine-induced swelling. ATP inhibits the GSH swelling, but ADP and AMP are ineffective. Mn-+ is a very potent inhibitor, but Mg++ is ineffective. Ethylenediaminetetraacetate is also an effective inhibitor of GSH-induced swelling. The respiratory inhibitors amytal and antimycin A do not inhibit the swelling action of GSH, but cyanide does; these findings are consistent with the view that the oxidation-reduction state of the respiratory chain between cytochrome c and oxygen is a determinant of GSH-induced swelling. Reversal of GSH-induced swelling by osmotic means or by ATP in KCl media could not be observed. Large losses of nucleotides and protein occur during the swelling by GSH, suggesting that the action is irreversible. The characteristically drastic swelling action of GSH could be prevented if L-thyroxine was also present in the medium. PMID:13630941

  13. Swelling Properties of Hydrogels Containing Phenylboronic Acids

    Directory of Open Access Journals (Sweden)

    Arum Kim

    2013-12-01

    Full Text Available Phenylboronic acids are a class of compounds that bind glucose and other sugars. When polymerized into hydrogels, they provide a convenient nonenzymatic means for sensing glucose concentration, provided competing sugars are present at negligible concentrations. In this paper we provide a comprehensive study of swelling of hydrogels containing methacrylamidophenylboronic acid (MPBA, as a function of pH and concentration of either glucose or fructose. In one set of hydrogels, MPBA is substituted at 20 mol·% in a polyacrylamide hydrogel [p(MPBA-co-AAm], while in a second set of hydrogels, 20 mol·% MPBA is supplemented with 20 mol·% of N-3-(dimethylaminopropyl methacrylamide [p(MPBA-co-DMP-co-AAm]. Swelling curves are markedly different for fructose and glucose, and for the two sets of hydrogels. While fructose alters swelling by binding and contributing to the ionization of MPBA, glucose does the same, but it also can form crosslinking bridges between separate chains, leading to hydrogel shrinkage. While the [p(MPBA-co-AAm] hydrogels behaved as polyacids, swelling monotonically with increasing pH, the [p(MPBA-co-DMP-co-AAm] hydrogels exhibited polyampholyte behavior, with swelling minima at intermediate pH values.

  14. High fluence swift heavy ion structure modification of the SiO{sub 2}/Si interface and gate insulator in 65 nm MOSFETs

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yao [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Key Lab of Microelectronics Sichuan Province, Sichuan University, Chengdu, Sichuan 610064 (China); College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Gao, Bo, E-mail: gaobo@scu.edu.cn [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Key Lab of Microelectronics Sichuan Province, Sichuan University, Chengdu, Sichuan 610064 (China); College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Gong, Min [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Key Lab of Microelectronics Sichuan Province, Sichuan University, Chengdu, Sichuan 610064 (China); College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Willis, Maureen [College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Yang, Zhimei [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Key Lab of Microelectronics Sichuan Province, Sichuan University, Chengdu, Sichuan 610064 (China); Guan, Mingyue [College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Li, Yun [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Key Lab of Microelectronics Sichuan Province, Sichuan University, Chengdu, Sichuan 610064 (China); College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China)

    2017-04-01

    In this work, a study of the structure modification, induced by high fluence swift heavy ion radiation, of the SiO{sub 2}/Si structures and gate oxide interface in commercial 65 nm MOSFETs is performed. A key and novel point in this study is the specific use of the transmission electron microscopy (TEM) technique instead of the conventional atomic force microscope (AFM) or scanning electron microscope (SEM) techniques which are typically performed following the chemical etching of the sample to observe the changes in the structure. Using this method we show that after radiation, the appearance of a clearly visible thin layer between the SiO{sub 2} and Si is observed presenting as a variation in the TEM intensity at the interface of the two materials. Through measuring the EDX line scans we reveal that the Si:O ratio changed and that this change can be attributed to the migration of the Si towards interface after the Si-O bond is destroyed by the swift heavy ions. For the 65 nm MOSFET sample, the silicon substrate, the SiON insulator and the poly-silicon gate interfaces become blurred under the same irradiation conditions.

  15. Synthesis and Swelling Behavior of pH-Sensitive Semi-IPN Superabsorbent Hydrogels Based on Poly(acrylic acid Reinforced with Cellulose Nanocrystals

    Directory of Open Access Journals (Sweden)

    Lim Sze Lim

    2017-11-01

    Full Text Available pH-sensitive poly(acrylic acid (PAA hydrogel reinforced with cellulose nanocrystals (CNC was prepared. Acrylic acid (AA was subjected to chemical cross-linking using the cross-linking agent MBA (N,N-methylenebisacrylamide with CNC entrapped in the PAA matrix. The quantity of CNC was varied between 0, 5, 10, 15, 20, and 25 wt %. X-ray diffraction (XRD data showed an increase in crystallinity with the addition of CNC, while rheology tests demonstrated a significant increase in the storage modulus of the hydrogel with an increase in CNC content. It was found that the hydrogel reached maximum swelling at pH 7. The potential of the resulting hydrogels to act as drug carriers was then evaluated by means of the drug encapsulation efficiency test using theophylline as a model drug. It was observed that 15% CNC/PAA hydrogel showed the potential to be used as drug carrier system.

  16. Data describing the swelling behavior and cytocompatibility of biodegradable polyelectrolyte hydrogels incorporating poly(L-lysine for applications in cartilage tissue engineering

    Directory of Open Access Journals (Sweden)

    Johnny Lam

    2016-06-01

    Full Text Available This data article presents data associated with the research article entitled “Evaluation of cell-laden polyelectrolyte hydrogels incorporating poly(L-lysine for applications in cartilage tissue engineering” (Lam et al., 2016 [1]. Synthetic hydrogel composites fabricated using oligo(poly(ethylene glycol fumarate (OPF macromers were utilized as vehicles for the incorporation of poly(L-lysine (PLL as well as the encapsulation of mesenchymal stem cells (MSCs. PLL-laden and PLL-free hydrogels were fabricated to characterize the main and interaction effects of OPF molecular weight, PLL molecular weight, and PLL loading density on the swelling and degradation of synthetic OPF hydrogels. Cells were then encapsulated within such hydrogels for in vitro culture and examined for viability, biochemical activity, and chondrogenic gene expression. These data, which are supplementary to the associated research article (Lam et al., 2016 [1], are presented here.

  17. Epithelial remodeling after femtosecond laser-assisted high myopic LASIK: comparison of stand-alone with LASIK combined with prophylactic high-fluence cross-linking.

    Science.gov (United States)

    Kanellopoulos, Anastasios J; Asimellis, George

    2014-05-01

    The aim of this study was to evaluate the possible topographic epithelial profile thickness changes (remodeling) after high myopic femtosecond laser in situ keratomileusis (LASIK) with concurrent prophylactic high-fluence cross-linking (CXL) in comparison with standard femtosecond LASIK. Preoperative and 6-month postoperative 3-dimensional epithelial thickness distribution maps were investigated through clinical spectral domain anterior-segment optical coherence tomography in 2 groups of femtosecond laser-assisted myopic LASIK cases. Group A represented 67 eyes treated additionally with concurrent prophylactic CXL (LASIK-Xtra); group B represented 72 eyes subjected to stand-alone femtosecond LASIK. Optical coherence tomography measurements of the epithelial thickness over the center 2-mm-diameter disk, mid-peripheral 5-mm rim, and overall (the entire 6-mm-diameter disc area) were investigated. The comparison of matched myopic correction subgroups indicated statistically significant differences in the epithelial thickness increase specifically between high myopia subgroups. For example, in group A (LASIK-Xtra), the mid-peripheral epithelial thickness increase was +3.79 and +3.95 μm for the "-8.00 to -9.00 diopter" and "-7.00 to -8.00 diopter" subgroups, which compare with increased thickness in group B (stand-alone LASIK), of +9.75 μm (P = 0.032) and +7.14 μm (P = 0.041), respectively, for the same subgroups. Application of prophylactic CXL concurrently with high myopic LASIK operation results in a statistically significant reduced epithelial increase in comparison with stand-alone LASIK. This comparison is observed between matched high myopic correction subgroups. This difference may correlate with higher regression rates and/or may depict increased biomechanical instability in stand-alone LASIK.

  18. The Swelling of Olympic Gels

    Science.gov (United States)

    Lang, Michael; Fischer, Jakob; Werner, Marco; Sommer, Jens-Uwe

    2014-03-01

    The swelling equilibrium of Olympic gels is studied by Monte Carlo Simulations. We observe that gels consisting of flexible cyclic molecules of a higher degree of polymerization N show a smaller equilibrium swelling degree Q ~N - 0 . 28φ0- 0 . 72 for the same monomer volume fraction φ0 at network preparation. This observation is explained by a disinterpenetration process of overlapping non-concatenated polymers upon swelling. In the limit of a sufficiently large number of concatenations per cyclic molecule we expect that the equilibrium degree of swelling becomes proportional to φ0- 1 / 2 independent of N. Our results challenge current textbook models for the equilibrium degree of swelling of entangled polymer networks. Now at: Bio Systems Analysis Group, Jena Centre for Bioinformatics (JCB) and Department for Mathematics and Computer Sciences, Friedrich Schiller University of Jena, 07743 Jena, Germany.

  19. Models of Hydrogel Swelling with Applications to Hydration Sensing

    Directory of Open Access Journals (Sweden)

    Kathryn Morton

    2007-09-01

    Full Text Available Hydrogels, polymers and various other composite materials may be used insensing applications in which the swelling or de-swelling of the material in response tosome analyte is converted via a transducer to a measurable signal. In this paper, we analyzemodels used to predict the swelling behavior of hydrogels that may be used in applicationsrelated to hydration monitoring in humans. Preliminary experimental data related toosmolality changes in fluids is presented to compare to the theoretical models. Overall,good experimental agreement with the models is achieved.

  20. Hand Swelling during Exercise: A Concern?

    Science.gov (United States)

    Hand swelling during exercise: A concern? What causes hand swelling during exercise? I walk several times a ... off. Answers from Edward R. Laskowski, M.D. Hand swelling during exercise is a fairly common problem. ...

  1. A single-blind, dose escalation, phase I study of high-fluence light-emitting diode-red light (LED-RL) on human skin: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Ho, Derek; Kraeva, Ekaterina; Wun, Ted; Isseroff, R Rivkah; Jagdeo, Jared

    2016-08-02

    Skin fibrosis is involved in a variety of pathologic conditions ranging from scar formation secondary to surgery or trauma to immune-mediated processes. Skin fibrosis is a significant international health problem with an estimated incidence of greater than 100 million people affected per year worldwide with few effective treatment options available. Preliminary in vitro data generated by our research group suggests that red light can function as a stand-alone treatment for skin fibrosis. To our knowledge, no prior clinical trials have been performed to determine the safety of high-fluence (dose) light-emitting diode-red light (LED-RL) phototherapy. The goal of this study is to evaluate the safety of LED-RL fluences from 160 J/cm(2) up to 640 J/cm(2) in healthy subjects. This is a single-blind, dose escalation, randomized controlled, phase I study to evaluate the safety of high-fluence LED-RL on human skin. The protocol for dose escalation requires subjects be enrolled sequentially in groups of five. Within each group, three subjects will be randomized to LED-RL phototherapy and two subjects randomized to mock therapy. Subjects in group 1 randomized to LED-RL phototherapy will receive the maximum recommended starting dose (160 J/cm(2)). LED-RL dose will be escalated in subsequent groups (320 J/cm(2), 480 J/cm(2) and 640 J/cm(2)). The maximally tolerated dose (MTD) is defined as the dose level below the dose producing unacceptable but reversible toxicity and is considered to be the upper limit of subject tolerance. After either a MTD has been established, or the study endpoint of 640 J/cm(2) has been achieved, an additional 27 LED-RL phototherapy subjects (for a total of 30) and 18 mock therapy subjects (for a total of 20) (determined randomly) will be enrolled. Each subject will receive a total of nine procedures, three times per week for three consecutive weeks. This study may provide important safety information on the effects of high-fluence LED

  2. Urinary steroid hormone analysis of ovarian cycles and pregnancy in mandrills (Mandrillus sphinx) indicate that menses, copulatory behavior, sexual swellings and reproductive condition are associated with changing estrone conjugates (E(1)C) and pregnanediol-3-glucuronide (PdG).

    Science.gov (United States)

    Phillips, Rebecca Sellin; Wheaton, Catharine J

    2008-07-01

    The objective of this study was to determine if sexual swellings in mandrills (Mandrillus sphinx) are a reflection of reproductive endocrine state. Urine samples were assayed using an enzyme immunoassay measuring pregnanediol-3-glucuronide (PdG) and estrone conjugates (E(1)C). Hormone patterns of ovarian cycles, pregnancy and lactation were characterized and compared with sexual swellings and copulations relative to menses and peak E(1)C. Cycle lengths averaging 28.7 days and pregnancy length of 181 days determined by hormonal and sexual swelling measures were similar to those reported in other Old World primate species. First day of copulation was observed during rising E(1)C concentrations and preceded observations of peak swelling by 1-2 days. Observations of peak sexual swellings occurred at or on the day after peak E(1)C and decreased following the ovulatory increase in PdG. Observations of menses and sexual swellings are a useful method to track mandrill ovarian cycles and can assist zoos in determining the reproductive state of females in their collections. Zoo Biol 27:320-330, 2008. (c) 2008 Wiley-Liss, Inc.

  3. RHEOLOGY AND SCALING BEHAVIOR OF SWELLING CLAY ...

    African Journals Online (AJOL)

    2012-12-31

    Dec 31, 2012 ... formed through the transition of a liquid sol into a space filling network structure which possesses a very high viscosity and a finite elastic modulus. Colloidal gel consists of fractal flocs formed by particle flocculation. At a critical gel volume fraction, ϕp c, the fractals aggregates forming in suspension begin to ...

  4. synthesis, rheological behavior and swelling properties of ...

    African Journals Online (AJOL)

    Preferred Customer

    PNIPAAm-co-AAm solution (mole ratios: 80/20). Table 1 describes the different formulations used in this work. After nitrogen bubbling for 15 min, free radical copolymerization of hydrogels was carried in glass tubes of 10 mm inner diameter at room temperature for 2 h, using APS and. TEMED as redox initiator. Subsequently ...

  5. Hydrogels for engineering: normalization of swelling due to arbitrary stimulus

    Science.gov (United States)

    Ehrenhofer, Adrian; Wallmersperger, Thomas

    2017-04-01

    In engineering, materials are chosen from databases: Engineers orient on specific parameters such as Young's modulus, yield stress or thermal expansion coefficients for a desired application. For hydrogels, the choice of materials is rather tedious since no generalized material parameters are currently available to quantify the swelling behavior. The normalization of swelling, which we present in the current work, allows an easy comparison of different hydrogel materials. Thus, for a specific application like a sensor or an actuator, an adequate material can be chosen. In the current work, we present the process of normalization and provide a course of action for the data analysis. Special challenges for hydrogels like hysteresis, conditional multi-sensitivity and anisotropic swelling are addressed. Then, the Temperature Expansion Model is shortly described and applied. Using the derived normalized swelling curves, a nonlinear expansion coefficient ß(F) is derived. The derived material behavior is used in an analytical model to predict the bending behavior of a beam made of thermo-responsive hydrogel material under an anisotropic temperature load. A bending behavior of the beam can be observed and the impact of other geometry and material parameters can be investigated. To overcome the limitations of the one-dimensional beam theory, the material behavior and geometry can be implemented in Finite Element analysis tools. Thus, novel applications for hydrogels in various fields can be envisioned, designed and tested. This can lead to a wider use of smart materials in sensor or actuator devices even by engineers without chemical background.

  6. Swelling

    Science.gov (United States)

    ... of the following: Acute glomerulonephritis Burns , including sunburn Chronic kidney disease Heart failure Liver failure from cirrhosis Nephrotic syndrome Poor nutrition Pregnancy Thyroid disease Too little albumin in the blood ( ...

  7. Cell swelling and volume regulation

    DEFF Research Database (Denmark)

    Hoffmann, Else Kay

    1992-01-01

    The extracellular space in the brain is typically 20% of the tissue volume and is reduced to at least half its size under conditions of neural insult. Whether there is a minimum size to the extracellular space was discussed. A general model for cell volume regulation was presented, followed...... by a discussion on how many of the generally involved mechanisms are identified in neural cells and (or) in astrocytes. There seems to be clear evidence suggesting that parallel K+ and Cl- channels mediate regulatory volume decrease in primary cultures of astrocytes, and a stretch-activated cation channel has...... been reported. The role of the different channels was discussed. A taurine leak pathway is clearly activated after cell swelling both in astrocytes and in neurones. The relations between the effect of glutamate and cell swelling were discussed. Discussion on the clearance of potassium from...

  8. Specimen Machining for the Study of the Effect of Swelling on CGR in PWR Environment.

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, Sebastien Paul [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-06-01

    This report describes the preparation of ten specimens to be used for the study of the effect of swelling on the propagation of irradiation assisted stress corrosion cracking cracks. Four compact tension specimens, four microscopy plates and two tensile specimens were machined from a AISI 304 material that was irradiated up to 33 dpa. The specimens had been machined such as to represent the behavior of materials with 3.7%swelling and <2% swelling.

  9. Swelling-resistant nuclear fuel

    Science.gov (United States)

    Arsenlis, Athanasios [Hayward, CA; Satcher, Jr., Joe; Kucheyev, Sergei O [Oakland, CA

    2011-12-27

    A nuclear fuel according to one embodiment includes an assembly of nuclear fuel particles; and continuous open channels defined between at least some of the nuclear fuel particles, wherein the channels are characterized as allowing fission gasses produced in an interior of the assembly to escape from the interior of the assembly to an exterior thereof without causing significant swelling of the assembly. Additional embodiments, including methods, are also presented.

  10. Calcium-alginate hydrogel swelling models are not pH-dependent

    Science.gov (United States)

    The recent article by Koc et al. (2008) reports predictive models for the swelling behavior of calcium-alginate hydrogels in response to changes in pH and temperature. We submit that the reported effect of “pH” on hydrogel swelling is unsupported by the data and is more properly interpreted as the ...

  11. Review of thickness swell in hardboard siding : effect of processing variables

    Science.gov (United States)

    Charles G. Carll

    1997-01-01

    Medium-density hardboard is used extensively as siding on residential structures. One hardboard behavior that can be measured in the laboratory is thickness swell after exposure to water. This report reviews the literature on processing variables that are known to or likely to influence thickness swell. Where the literature on hardboard is sparse, research on other...

  12. Optical transmission damage of undoped and Ce doped Y{sub 3}Al{sub 5}O{sub 12} scintillation crystals under 24 GeV protons high fluence

    Energy Technology Data Exchange (ETDEWEB)

    Auffray, E. [CERN, Geneva (Switzerland); Fedorov, A. [Research Institute for Nuclear Problems, Minsk (Belarus); Dormenev, V. [Justus Liebig University, Giessen (Germany); Houžvička, J. [CRYTUR, spol. s r.o., Palackého 175, 51101 Turnov (Czech Republic); Korjik, M., E-mail: Mikhail.Korjik@cern.ch [Research Institute for Nuclear Problems, Minsk (Belarus); Lucchini, M.T. [CERN, Geneva (Switzerland); Mechinsky, V. [Research Institute for Nuclear Problems, Minsk (Belarus); Ochesanu, S. [CRYTUR, spol. s r.o., Palackého 175, 51101 Turnov (Czech Republic)

    2017-06-01

    This report presents results on the optical transmission damage of undoped and Ce doped Y{sub 3}Al{sub 5}O{sub 12} scintillation crystals under high fluence of 24 GeV protons. We observed that, similarly to other middle heavy scintillators, it possesses the unique radiation hardness at fluence values as high as 5×10{sup 14} p/cm{sup 2} and it is thus promising for the application in the detectors at High Luminosity LHC. The crystalline structure of the garnet scintillator allows to control and further optimize its scintillation parameters, such as scintillation decay time and emission wavelength, and shows a limited set of the radioisotopes after the irradiation with protons.

  13. Nanodomain Swelling of Water-Equilibrated Block Copolymer Electrolyte Membranes

    Science.gov (United States)

    Chen, Chelsea; Jiang, Xi; Balsara, Nitash

    In this work, we examine the nanoscale swelling behavior of block copolymer electrolytes immersed in liquid water. A series of sulfonated polystyrene- b-polyethylene- b-polystyrene (S-SES) membranes having the same chemical composition but with different morphologies are prepared. We use small angle X-ray scattering (SAXS), cryogenic scanning transmission electron microscopy (cryo-STEM) and cryogenic electron tomography to characterize the nanodomain swelling of S-SES membranes. The relative increase of the nanodomain size upon hydration shows a transition which coincides with a morphological transition from lamellar to bicontinuous morphology. The nanodomain swelling of S-SES membranes with bicontinuous morphology is smaller than that of S-SES membranes with lamellar morphology while the water uptake is much larger. Electron tomography revealed that swelling of the membrane with bicontinuous morphology was spatially isotropic, which is the origin of the smaller relative domain size increase compared to the lamellar membranes whose swelling is anisotropic. This work was primarily supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under Contract No. DE-AC02-05-CH11231 within the Electron Microscopy of Soft Matter Program (KC11BN).

  14. Swelling soils in the road structures

    Science.gov (United States)

    Pruška, Jan; Šedivý, Miroslav

    2017-09-01

    There are frequent problems with the soil swelling in the road construction in the past time. This phenomenon is known for decades. This situation is notably given by insufficient knowledge of this problem and difficulties with input parameters describing the swelling process. The paper in the first part proposed regression relations to predict swelling pressure, time of swelling and swelling strain for different initial water contents for soils and improvement soils. The relations were developed by using artificial neural network and QCExpert Professional software (on the data from site investigations by GeoTec-GS, a.s. and experimental data from CTU in Prague). The advantage of the relations is based on using the results of the basic soil tests (plasticity index, consistency index and colloidal activity) as input parameters. The authors inform the technical public with their current knowledge of the problems with the soil swelling on the motorway in the second part of the paper.

  15. Swelling of Clay-Sulfate Rocks: A Review of Processes and Controls

    Science.gov (United States)

    Butscher, Christoph; Mutschler, Thomas; Blum, Philipp

    2016-04-01

    The swelling of clay-sulfate rocks is a major threat in tunnel engineering, causing serious damage to tunnels and producing high additional costs during tunnel construction and operation. The swelling problem is also known from other geotechnical fields, such as road and bridge construction, and in conjunction with geothermal drillings. The planning of counter measures that would stop or minimize the swelling is extremely difficult, and it is currently impossible to predict the swelling behavior of an actual geotechnical project. One of the reasons is our limited knowledge of the processes involved in the swelling of clay-sulfate rocks, and of the geological, mineralogical, chemical, hydraulic and mechanical controls of the swelling. This article presents a literature review of processes in swelling clay-sulfate rocks and associated controls. Numerical models that aim at simulating the processes and controls are also included in this review, and some of the remaining open questions are pointed out. By focusing on process-related work in this review, the article intends to stimulate further research across disciplines in the field of swelling clay-sulfate rocks to finally get a step further in managing the swelling problem in geotechnical projects.

  16. Diffuse postoperative cerebellar swelling in medulloblastoma: report of two cases.

    Science.gov (United States)

    Ogiwara, Hideki; Dipatri, Arthur J; Bowman, Robin M; Tomita, Tadanori; Alden, Tord D

    2011-05-01

    We report two cases of diffuse cerebellar swelling with upward transtentorial herniation following medulloblastoma resection. We present our insight for managing medulloblastoma with aggressive clinical behavior. Case 1 is a 32-month-old boy. Magnetic resonance imaging (MRI) revealed fourth ventricular mass with diffuse leptomeningeal metastasis. He underwent gross total resectioning of the tumor and histopathology revealed a large cell medulloblastoma. A ventriculoperitoneal shunt was placed on the 25th postoperative day. Ten days after he developed lethargy, and MRI showed diffuse cerebellar swelling with upward herniation. He underwent emergent posterior fossa decompression; however, he remained unresponsive since then. Case 2 is a 31-month-old boy. MRI revealed a fourth ventricular mass with diffuse leptomeningeal metastasis. He underwent gross total resection and histopathology was a large cell medulloblastoma. Due to developing ventriculomegaly, extraventricular drainage was reinserted on the 11th postoperative day. Four days after, he developed lethargy and decerebrate posturing. MRI showed diffuse cerebellar swelling with upward herniation. He underwent aggressive posterior fossa decompression. Chemotherapy was started postoperatively. Gradually, his movement of extremities improved. On the 79th postoperative day, he started to follow commands and talk some words. He was discharged to a rehabilitation institute and has continued to improve since then. Diffuse cerebellar swelling with upward herniation could occur in patients with aggressive medulloblastoma postoperatively. Our patients had diffuse leptomeningeal dissemination of the tumor at the initial presentation. Close monitoring and prompt diagnosis with earlier surgical posterior fossa decompression and administration of chemotherapy may prevent irreversible neurologic deterioration.

  17. Submandibular swelling: Tooth or salivary stone?

    Directory of Open Access Journals (Sweden)

    Pasquale Capaccio

    2013-01-01

    Sialolithiasis should always be considered in the diagnostic iter of painful submandibular swelling. A careful evaluation of recurrence and characteristics of signs and symptoms associated to the swelling can help in making the correct diagnosis and planning a proper therapeutic strategy.

  18. Hand Swelling during Exercise: A Concern?

    Science.gov (United States)

    Diseases and Conditions Edema What causes hand swelling during exercise? I walk several times a week, and my fingers get puffy to the ... 07, 2015 Original article: http://www.mayoclinic.org/diseases-conditions/edema/expert-answers/hand-swelling/FAQ-20058255 . Mayo Clinic Footer Legal Conditions ...

  19. Coal swelling and thermoplasticity under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Ndaji, F.E.; Butterfield, I.M.; Thomas, K.M. (Newcastle upon Tyne University, Newcastle upon Tyne (United Kingdom). Northern Carbon Research Labs., Dept. of Chemistry)

    1992-01-01

    The literature on the following topics is reviewed: swelling and agglomeration of coal; measurements of swelling index and dilatometric and plastometric properties at high pressures; and the effects of oxidation, tar addition and minerals on high-pressure thermoplastic properties. 34 refs., 6 figs.

  20. Depth profile investigation of β-FeSi{sub 2} formed in Si(1 0 0) by high fluence implantation of 50 keV Fe ion and post-thermal vacuum annealing

    Energy Technology Data Exchange (ETDEWEB)

    Lakshantha, Wickramaarachchige J.; Kummari, Venkata C.; Reinert, Tilo; McDaniel, Floyd D. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, TX 76203 (United States); Rout, Bibhudutta, E-mail: bibhu@unt.edu [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, TX 76203 (United States); Center for Advanced Research and Technology, University of North Texas, 3940 North Elm Street, Denton, TX 76207 (United States)

    2014-08-01

    A single phase polycrystalline β-FeSi{sub 2} layer has been synthesized at the near surface region by implantation in Si(1 0 0) of a high fluence (∼10{sup 17} atoms/cm{sup 2}) of 50 keV Fe ions and subsequent thermal annealing in vacuum at 800 °C. The depth profile of the implanted Fe atoms in Si(1 0 0) were simulated by the widely used transportation of ions in matter (TRIM) computer code as well as by the dynamic transportation of ions in matter code (T-DYN). The simulated depth profile predictions for this heavy ion implantation process were experimentally verified using Rutherford Backscattering Spectrometry (RBS) and X-ray Photoelectron Spectroscopy (XPS) in combination with Ar-ion etching. The formation of the β-FeSi{sub 2} phase was monitored by X-ray diffraction measurements. The T-DYN simulations show better agreement with the experimental Fe depth profile results than the static TRIM simulations. The experimental and T-DYN simulated results show an asymmetric distribution of Fe concentrated more toward the surface region of the Si substrate.

  1. The Combination of Resveratrol and High-Fluence Light Emitting Diode-Red Light Produces Synergistic Photobotanical Inhibition of Fibroblast Proliferation and Collagen Synthesis: A Novel Treatment for Skin Fibrosis.

    Science.gov (United States)

    Mamalis, Andrew; Jagdeo, Jared

    2017-01-01

    Skin fibrosis is a debilitating condition that significantly impacts patient quality of life. Ultraviolet phototherapy is currently used to treat several diseases featuring skin fibrosis. High-fluence light-emitting diode-generated red light (HF-LED-RL) does not cause DNA damage associated with skin cancer, and it is generally regarded as safe, portable, and cost-effective. Early clinical observations suggest that LED-generated light may possess antifibrotic effects, although these findings are largely unexplored. Previously published research demonstrated that HF-LED-RL decreases fibroblast proliferation and collagen in vitro. The goal of this study was to compare the combination effects of HF-LED-RL alone with HF-LED-RL in combination with resveratrol. It is hypothesized that resveratrol, an active ingredient in red wine, a potent antioxidant scavenger of reactive oxygen species, and an inhibitor of collagen production, may synergistically decrease fibroblast proliferation and collagen production when combined with HF-LED-RL. In this study, evidence is provided that resveratrol combined with HF-LED-RL acts synergistically to decrease fibroblast proliferation and procollagen 1A1 production, and this represents a new potential therapeutic modality that is termed the "photobotanical" effect due to the combined light and botanical properties observed. The study, discovery, and use of photobotanical combinations may usher in new therapeutics or phototherapy adjuvants for the treatment of dermatologic diseases.

  2. High resolution interferometry as a tool for characterization of swelling of weakly charged hydrogels subjected to amphiphile and cyclodextrin exposure

    OpenAIRE

    Gao, Ming; Gawel, Kamila; Stokke, Bjørn Torger

    2013-01-01

    A high resolution interferometric technique was used to determine swelling behavior of weakly charged polyacrylamide hydrogels in the presence of oppositely charged surfactants and subsequent exposure to cyclodextrins. Hydrogels of copolymerized acrylamide and 2-acrylamido-2-methyl-1-propanesulfonic acid (0.22, 0.44, 0.88 mol%) and crosslinked with bisacrylamide (3, 6, 12 mol%) were employed. The equilibrium swelling and swelling kinetics of the hydrogels were determined with 2 nanometer reso...

  3. Kinetics of solvent-swelling of coal

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, G.; Rincon, J.M.; Mora, E. [Lab. de Combustibles, Univ. Nacional de Colombia, Santafe de Bogota (Colombia); Klose, W. [GF Thermodynamik, Kassel Univ. (Germany)

    1997-12-31

    The kinetics of coal swelling by solvent of different basic strength is followed; Cerrejon and Yerbabuena (Colombian coals), Sacer-Endsdorf and Ruhr-Anna (Germany coals) were swollen with tetrahydrofuran, pyridine and butylamine. It was found that the swelling index decreases both with solvent basicity and coal rank. When the coal rank increases, the rates of swelling are: Initially, THF follows Fickian diffusion then follows anomalous case near case II; pyridine follows anomalous case near Fickian diffusion, whereas rate with butylamine initially is anomalous case of transport to Fickian diffusion. (orig.)

  4. Swells of the East China Sea

    Science.gov (United States)

    Tao, Aifeng; Yan, Jin; Pei, Ye; Zheng, Jinhai; Mori, Nobuhito

    2017-08-01

    Over the past few decades, an increasing number of marine activities have been conducted in the East China Sea, including the construction of various marine structures and the passage of large ships. Marine safety issues are paramount and are becoming more important with respect to the likely increase in size of ocean waves in relation to global climate change and associated typhoons. In addition, swells also can be very dangerous because they induce the resonance of floating structures, including ships. This study focuses on an investigation of swells in the East China Sea and uses hindcast data for waves over the past 5 years in a numerical model, WAVEWATCH III (WW3), together with historical climate data. The numerical calculation domain covers the entire North West Pacific. Next, swells are separated and analyzed using simulated wave fields, and both the characteristics and generation mechanisms of swells are investigated.

  5. Foot Swelling during Air Travel: A Concern?

    Science.gov (United States)

    ... concern? What causes leg and foot swelling during air travel? Answers from Sheldon G. Sheps, M.D. ... had major surgery or you take birth control pills, for example — consult your doctor before flying. He ...

  6. RESEARCH OF SWELLING OF SUZAKH CLAYS

    Directory of Open Access Journals (Sweden)

    Kubetskiy Valeriy Leonidovich

    2012-07-01

    Full Text Available In the course of construction of Sangtudinsky hydropower plant-1 on the River Vakhsh, it was deemed necessary to identify clay swelling properties in the event of alterations of the humidity mode of fructured half-rock soils, or the Suzakh clay, that accommodated tunnel-shaped water outlets within a section that was 75 meters long. The depth of tunnels was about 100 m. Any interaction with swelling soils could lead to destruction of the tunnel lining. Suzakh clays demonstrated the following physical and mechanical properties: density of particles of soil ρ= 2,69 g/cm; soil density ρ = 2.40-2.47 g/cm; porosity of 8.2-10.8 %; ultimate resistance to uniaxial compression = 13.1-31.0 MPa. Water saturated clay samples disintegrated into cloddy fragments; the rate of a longitudinal ultrasonic wave in the area of unaltered soils was equal to = 2500 m/c; repulse coefficient k was equal to 15 MPa/m; solidity coefficient (according to Protodyakonov was equal to 1,5; modulus of deformation in the massif was equal to 0.23 х10 MPa. The author proposed a methodology and designed a pilot set of equipment units designated for the identification of the swelling properties of fractured half-rock soils. Results of the pilot unit operation are presented in the article. Swelling properties are based on the monolith testing results. The programme contemplated a set of experiments held in various limit states on the surface of monoliths. Dependence between the swelling pressure and the swelling deformation in the course of water saturation was identified. The experiment demonstrates that alterations of the humidity mode of free surface Suzakh clays cause the relative deformation of swelling up to 1.1 %, and if the lining is rigid, the swelling pressure can exceed 4 MPa.

  7. Scrotal swellings in the under 5s.

    OpenAIRE

    Wilson-Storey, D

    1987-01-01

    Scrotal swelling is a common cause of referral to the paediatric surgical services in Edinburgh, constituting 12% of total admissions. Of these, 2818 (65%) were in boys under the age of 5 years, with a wide variety, including inguinal hernias, hydroceles, testicular torsion, tumours, and some interesting but uncommon conditions. A retrospective study was performed over a 12 year period to assess the incidence, aetiology, mode of presentation, disease, and management of scrotal swellings in bo...

  8. Assessment of void swelling in austenitic stainless steel PWR core internals.

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. M.; Energy Technology

    2006-01-31

    As many pressurized water reactors (PWRs) age and life extension of the aged plants is considered, void swelling behavior of austenitic stainless steel (SS) core internals has become the subject of increasing attention. In this report, the available database on void swelling and density change of austenitic SSs was critically reviewed. Irradiation conditions, test procedures, and microstructural characteristics were carefully examined, and key factors that are important to determine the relevance of the database to PWR conditions were evaluated. Most swelling data were obtained from steels irradiated in fast breeder reactors at temperatures >385 C and at dose rates that are orders of magnitude higher than PWR dose rates. Even for a given irradiation temperature and given steel, the integral effects of dose and dose rate on void swelling should not be separated. It is incorrect to extrapolate swelling data on the basis of 'progressive compounded multiplication' of separate effects of factors such as dose, dose rate, temperature, steel composition, and fabrication procedure. Therefore, the fast reactor data should not be extrapolated to determine credible void swelling behavior for PWR end-of-life (EOL) or life-extension conditions. Although the void swelling data extracted from fast reactor studies is extensive and conclusive, only limited amounts of swelling data and information have been obtained on microstructural characteristics from discharged PWR internals or steels irradiated at temperatures and at dose rates comparable to those of a PWR. Based on this relatively small amount of information, swelling in thin-walled tubes and baffle bolts in a PWR is not considered a concern. As additional data and relevant research becomes available, the newer results should be integrated with existing data, and the worthiness of this conclusion should continue to be scrutinized. PWR baffle reentrant corners are the most likely location to experience high swelling

  9. Current status of gas migration and swelling experiments using engineering scale model for immediate depth disposal in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Higashihara, Tomohiro; Ono, Makoto; Kawaragi, Chie; Saito, Shigeyuki [Japan Nuclear Energy Society (JNES), Tokyo (Japan)

    2010-07-01

    In intermediate depth disposal facility of radioactive waste in Japan, waste is surrounded with bentonite layer to retard interaction of the waste and groundwater, because the bentonite layer saturated with the groundwater has very low hydraulic conductivity. On the other hand, it is important to confirm stability of barrier system for stress generated together with swelling of the bentonite and to understand effect of increase of gas pressure because of generation of hydrogen gas by corrosion of metallic waste. To understand and evaluate the swelling behavior of the bentonite layer, JNES carries out the experiment. In the experiments, we carry out the swelling experiment to examine the swelling behavior of the bentonite layer and the gas migration experiment to understand the gas migration behavior in the bentonite layer, using engineering scale model of the disposal facility. The swelling experiment has been in operation since June 2010. After this experiment, the gas migration experiment will start in July 2011. (orig.)

  10. Swelling instabilities in patterned, microscale gels

    Science.gov (United States)

    Toomey, Ryan; Dupont, Samuel

    2012-02-01

    Hydrogels facilitate reconfigurable structures with response integrated at the material level. Response is engendered by a competing mechanism: the elasticity of the network ounterbalances expansion by the solvent. If the strength of expansion can be controlled by an environmental cue, the hydrogel can be adjusted in situ. The equilibrium state occurs when the osmotic stress exerted by the solvent in the gel equals the osmotic pressure of the solvent outside the gel. For a free structure, the equilibrium state corresponds to homogenous swelling. If a free surface of the gel is mechanically constrained, however, the dimensions available for the relief of the osmotic stress are reduced, resulting in non-uniform or inhomogeneous swelling. In this study, we demonstrate how mechanical constraints impose differential gel swelling and buckling in patterned gels. Depending on the initial geometry of the constrained gel, three general modes of swelling-induced deformation can be observed: lateral differential swelling, bulk sinusoidal buckling, and surface wrinkling. Through confocal microscopy and 3D image rendering, the mechanics of swelling has been evaluated in the context of linear elasticity theory.

  11. Fractional cable equation for general geometry: A model of axons with swellings and anomalous diffusion

    Science.gov (United States)

    López-Sánchez, Erick J.; Romero, Juan M.; Yépez-Martínez, Huitzilin

    2017-09-01

    Different experimental studies have reported anomalous diffusion in brain tissues and notably this anomalous diffusion is expressed through fractional derivatives. Axons are important to understand neurodegenerative diseases such as multiple sclerosis, Alzheimer's disease, and Parkinson's disease. Indeed, abnormal accumulation of proteins and organelles in axons is a hallmark of these diseases. The diffusion in the axons can become anomalous as a result of this abnormality. In this case the voltage propagation in axons is affected. Another hallmark of different neurodegenerative diseases is given by discrete swellings along the axon. In order to model the voltage propagation in axons with anomalous diffusion and swellings, in this paper we propose a fractional cable equation for a general geometry. This generalized equation depends on fractional parameters and geometric quantities such as the curvature and torsion of the cable. For a cable with a constant radius we show that the voltage decreases when the fractional effect increases. In cables with swellings we find that when the fractional effect or the swelling radius increases, the voltage decreases. Similar behavior is obtained when the number of swellings and the fractional effect increase. Moreover, we find that when the radius swelling (or the number of swellings) and the fractional effect increase at the same time, the voltage dramatically decreases.

  12. Fractional cable equation for general geometry: A model of axons with swellings and anomalous diffusion.

    Science.gov (United States)

    López-Sánchez, Erick J; Romero, Juan M; Yépez-Martínez, Huitzilin

    2017-09-01

    Different experimental studies have reported anomalous diffusion in brain tissues and notably this anomalous diffusion is expressed through fractional derivatives. Axons are important to understand neurodegenerative diseases such as multiple sclerosis, Alzheimer's disease, and Parkinson's disease. Indeed, abnormal accumulation of proteins and organelles in axons is a hallmark of these diseases. The diffusion in the axons can become anomalous as a result of this abnormality. In this case the voltage propagation in axons is affected. Another hallmark of different neurodegenerative diseases is given by discrete swellings along the axon. In order to model the voltage propagation in axons with anomalous diffusion and swellings, in this paper we propose a fractional cable equation for a general geometry. This generalized equation depends on fractional parameters and geometric quantities such as the curvature and torsion of the cable. For a cable with a constant radius we show that the voltage decreases when the fractional effect increases. In cables with swellings we find that when the fractional effect or the swelling radius increases, the voltage decreases. Similar behavior is obtained when the number of swellings and the fractional effect increase. Moreover, we find that when the radius swelling (or the number of swellings) and the fractional effect increase at the same time, the voltage dramatically decreases.

  13. Clayey landslide initiation and acceleration strongly modulated by soil swelling

    Science.gov (United States)

    Schulz, William; Smith, Joel B.; Wang, Gonghui; Jiang, Yao; Roering, Joshua J.

    2018-01-01

    Largely unknown mechanisms restrain motion of clay-rich, slow-moving landslides that are widespread worldwide and rarely accelerate catastrophically. We studied a clayey, slow-moving landslide typical of thousands in northern California, USA, to decipher hydrologic-mechanical interactions that modulate landslide dynamics. Similar to some other studies, observed pore-water pressures correlated poorly with landslide reactivation and speed. In situ and laboratory measurements strongly suggested that variable pressure along the landslide's lateral shear boundaries resulting from seasonal soil expansion and contraction modulated its reactivation and speed. Slope-stability modeling suggested that the landslide's observed behavior could be predicted by including transient swell pressure as a resistance term, whereas modeling considering only transient hydrologic conditions predicted movement 5–6 months prior to when it was observed. All clayey soils swell to some degree; hence, our findings suggest that swell pressure likely modulates motion of many landslides and should be considered to improve forecasts of clayey landslide initiation and mobility.

  14. Swelling-Induced Deformation of Nanopatterned Polymer Lines

    Science.gov (United States)

    Tirumala, Vijay; Stafford, Christopher; Huang, Rui; Ocola, Leonidas

    2008-03-01

    The deformation behavior of isolated poly (N-isopropylacrylamide) nanolines due to swelling is studied to quantitatively establish the parameters governing their mechanical stability. The features are patterned using electron-beam lithography and are supported on a rigid substrate. In the range of 50-250 nm linewidth, we show that the swollen lines undergo Euler buckling with stable higher order modes due to the constraint for polymer chain expansion at the substrate interface. The critical wavelength for buckling surprisingly increases with decreasing line length. The linear swelling strain thus becomes a function of the initial length and decreases dramatically as the line length approaches twice the buckling wavelength for infinitely long lines. A critical length, larger than the buckling wavelength for infinitely long features, exists below which the lines remain mechanically stable regardless of their crosslink density. For sufficiently long lines with height-to-width aspect-ratio in the range 0.5-1.7, the scaling relationship for buckling wavelength vs. linewidth suggests that swelling is anisotropic and is more dominant through height than width. The results established in this study are more generally applicable to nanopatterned polymer lines since buckling instabilities involve simultaneous bending and compression, which deform the material with equal force but in opposite directions.

  15. Effects of the Charge Ions Strength on the Swelling of Organic-Inorganic Nanogels

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Qin; Lu, Xiangguo; Wang, Jing; Guo, Qi; Niu, Liwei [Northeast Petroleum University, Daqing (China)

    2016-07-15

    The swelling behavior and swelling mechanism of hydrogels can be greatly affected by the charge strength of ions in them. To investigate such effects, we prepared two gels: a carboxylic acid gel (CAG) and a poly (2-acrylamide–methyl propane sulfonic acid) gel (SAG) based on starchy polyacrylamide (PAM) nanocomposite gels, both with montmorillonite, which underwent in situ intercalation, and used them as probes in swelling experiments. The equilibrium swelling rates (ESRs) of the hydrogels in both salt water and acidic water strongly depended on the charge strength of the ions in the chains. SAG had a higher ESR than CAG at the same mole ratio of polymer/water, which is attributed to the greater electrostatic repulsion between the strong electrolyte ions of SAG. Both water salinity and hydrogen ion contact of the hydrogels weakened ESR with the enhancement of charge ionic strength. The downward trend of ESR with increasing concentration of salt or hydrogen ions became weaker in SAG compared to CAG, which is attributed to the shielding and deprotonation effects of the strong electrolyte ions. Regarding the swelling mechanism, the chain relaxation occurred in neutral and acidic solutions for SAG and in neutral and weak acidic solutions for CAG, but water diffusion dominated in strong acidic solutions for CAG, leading to different swelling behaviors.

  16. A Hamiltonian Formulation On Tsunami Over Swell

    Science.gov (United States)

    TIAN, M.; Sheremet, A.; Kaihatu, J. M.

    2012-12-01

    Tsunami induced by earthquakes typically evolves shore-ward with a significant amplification of amplitude during the last stages of shoaling. This study focuses on tsunami evolution in shallow water under the effects of the oceanographic environment such as breaking and tsunami- swell interaction. One generally describes wave breaking directly with a discontinuity in the solution to the classical nonlinear shallow water equations (NLSW) (e.g., Stoker 1985). This wave-front steepness calculation, however, has the potential problem that for the case of the single wave defined by solitary wave, breaking occurs much closer to the wave crest so that the method is formally invalid (Madsen et. al. 2008). Li and Raichlen (2002) applied a weighted essentially non-oscillatory (WENO) shock-capturing scheme in the numerical NSWE model to capture the wave breaking process. The problem arises that a convenient hamiltonian formalism is lacking to describe wave breaking. One wants to evaluate breaking by deducing the decay of the tsunami energy in a straightforward manner. The linear effect of the tsunami background circulation on swell is well known (e.g., Madsen et. al. 2008). However, Kaihatu and El Safty(2011) hypothesized that this is only one "half" of the mutual interaction between the tsunami and the overlying swell field, which might have subtle effects on the tsunami front-face steepness and breaking process. These effects were observed in a laboratory experiments (Kaihatu and El Safty 2011). It was observed that the presence of swell affects the maximum surface amplitude of overall wave field and produces significant energy shifts to high frequencies, thus promoting tsunami breaking. The theoretical study for tsunami-swell interaction requires a phase-resolving wave-wave interaction model. In this study, we derive a Hamiltonian formulation for the tsunami-swell interaction using the quasi stream-function formulation. This formalism is better able to handle uneven

  17. Swelling response of radiation synthesized 2-hydroxyethylmethacrylate-co-[2-(methacryloyloxy)ethyl] trimethylammonium chloride hydrogels under various in vitro conditions.

    Science.gov (United States)

    Goel, N K; Kumar, Virendra; Bhardwaj, Y K; Chaudhari, C V; Dubey, K A; Sabharwal, S

    2009-01-01

    High-energy (60)Co gamma radiation has been used to synthesize 2-hydroxyethylmethacrylate-co-[2-(methacryloyloxy)ethyl]trimethylammonium chloride (HEMA-co-MAETC) polyelectrolyte hydrogels. HEMA-co-MAETC co-polymer gels were characterized and investigated for swelling behaviour in different swelling conditions. Fourier transformed infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) techniques were used to characterize the co-polymer gels. Swelling extent of the gels was found to be a linear function of MAETC content in the gels. The effect of ionic strength, temperature, pH, some solutes of biological importance like glucose, urea, and surfactants such as Triton-X and deoxycholic acid on swelling behavior have been reported. The swelling of gels at higher temperature enhanced the swelling rates but not the swelling extent. HEMA-co-MAETC hydrogel exhibited an excellent responsive characteristic to the ionic strength of the swelling medium. It was found that the swelling of the co-polymer gel at 60 degrees C reduced the swelling-deswelling cycle time by approx. 30% without altering the swelling extent. The gels were also investigated for their swelling in aqueous solutions of anionic dyes, acid blue 25 (AB25), acid blue (AB74) and acid yellow 99 (AY99), and were found to be suitable for dye uptake applications.

  18. NMR imaging and cryoporometry of swelling clays

    Science.gov (United States)

    Dvinskikh, Sergey V.; Szutkowski, Kosma; Petrov, Oleg V.; Furó, István.

    2010-05-01

    Compacted bentonite clay is currently attracting attention as a promising "self-sealing" buffer material to build in-ground barriers for the encapsulation of radioactive waste. It is expected to fill up the space between waste canister and surrounding ground by swelling and thus delay flow and migration from the host rock to the canister. In environmental sciences, evaluation and understanding of the swelling properties of pre-compacted clay are of uttermost importance for designing such buffers. Major goal of present study was to provide, in a non-invasive manner, a quantitative measure of bentonite distribution in extended samples during different physical processes in an aqueous environment such as swelling, dissolution, and sedimentation on the time scale from minutes to years. The propagation of the swelling front during clay expansion depending on the geometry of the confining space was also studied. Magnetic resonance imaging and nuclear magnetic resonance spectroscopy were adapted and used as main experimental techniques. With this approach, spatially resolved movement of the clay/water interface as well as clay particle distributions in gel phase can be monitored [1]. Bulk samples with swelling in a vertical tube and in a horizontal channel were investigated and clay content distribution profiles in the concentration range over five orders of magnitude and with sub-millimetre spatial resolution were obtained. Expansion rates for bulk swelling and swelling in narrow slits were compared. For sodium-exchanged montmorillonite in contact with de-ionised water, we observed a remarkable acceleration of expansion as compared to that obtained in the bulk. To characterize the porosity of the clay a cryoporometric study [2] has been performed. Our results have important implications to waste repository designs and for the assessment of its long-term performance. Further research exploring clay-water interaction over a wide variety of clay composition and water ionic

  19. Unusual presentation of ulcerative postauricular swelling as ...

    African Journals Online (AJOL)

    The swelling became ulcerative and associated with progressive tinnitus and hoarseness of voice. The patient was investigated. Fine‑needle aspiration cytology suggested sebaceous cell carcinoma. Then excision biopsy was done, and histopathological examination of excised tissue confirmed the diagnosis. Extraorbital ...

  20. An unusual swelling in the male perineum.

    Science.gov (United States)

    Parnham, Arie Stewart; Freeman, Alex; Kirkham, Alex; Muneer, Asif

    2015-01-22

    Median raphe cysts are a rare, congenital entity. We present a case and review the literature in respect to a 35-year-old man with a non-visible, painless midline swelling in the anterior perineum initially thought to be a liposarcoma. Subsequent histopathological examination confirmed a median raphe cyst. 2015 BMJ Publishing Group Ltd.

  1. An unusual swelling in the male perineum

    National Research Council Canada - National Science Library

    Parnham, Arie Stewart; Freeman, Alex; Kirkham, Alex; Muneer, Asif

    2015-01-01

    Median raphe cysts are a rare, congenital entity. We present a case and review the literature in respect to a 35-year-old man with a non-visible, painless midline swelling in the anterior perineum initially thought to be a...

  2. PREVENTION OF PHOSPHATE - INDUCED MITOCHONDRIAL SWELLING

    Science.gov (United States)

    Kroll, Arnold J.; Kuwabara, Toichiro

    1962-01-01

    The prevention of phosphate-induced mitochondrial swelling in the whole retina of the rabbit was studied with the electron microscope. It was found that a mixture of ATP, Mg++, and bovine serum albumin protected the mitochondria in vitro. This finding confirmed the results obtained spectrophotometrically with isolated rat liver mitochondria by Lehninger. PMID:13927020

  3. A Biophysical Model for Cytotoxic Cell Swelling

    NARCIS (Netherlands)

    Dijkstra, Koen; Hofmeijer, Jeannette; van Gils, Stephanus A.; van Putten, Michel Johannes Antonius Maria

    2016-01-01

    We present a dynamic biophysical model to explain neuronal swelling underlying cytotoxic edema in conditions of low energy supply, as observed in cerebral ischemia. Our model contains Hodgkin—Huxley-type ion currents, a recently discovered voltage-gated chloride flux through the ion exchanger

  4. Swell Propagation over Indian Ocean Region

    Directory of Open Access Journals (Sweden)

    Suchandra A. Bhowmick

    2011-06-01

    Full Text Available Swells are the ocean surface gravity waves that have propagated out of their generating fetch to the distant coasts without significant attenuation. Therefore they contain a clear signature of the nature and intensity of wind at the generation location. This makes them a precursor to various atmospheric phenomena like distant storms, tropical cyclones, or even large scale sea breeze like monsoon. Since they are not affected by wind once they propagate out of their generating region, they cannot be described by regional wave models forced by local winds. However, their prediction is important, in particular, for ship routing and off shore structure designing. In the present work, the propagation of swell waves from the Southern Ocean and southern Indian Ocean to the central and northern Indian Ocean has been studied. For this purpose a spectral ocean Wave Model (WAM has been used to simulate significant wave height for 13 years from 1993–2005 using NCEP blended winds at a horizontal spatial resolution of 1° × 1°. It has been observed that Indian Ocean, with average wave height of approximately 2–3 m during July, is mostly dominated by swell waves generated predominantly under the extreme windy conditions prevailing over the Southern Ocean and southern Indian Ocean. In fact the swell waves reaching the Indian Ocean in early or mid May carry unique signatures of monsoon arriving over the Indian Subcontinent. Pre-monsoon month of April contains low swell waves ranging from 0.5–1 m. The amplitudes subsequently increase to approximately 1.5–2 meters around 7–15 days prior to the arrival of monsoon over the Indian Subcontinent. This embedded signature may be utilized as one of the important oceanographic precursor to the monsoon onset over the Indian Ocean.

  5. Shrinkage/swelling of compacted clayey loose and dense soils

    Science.gov (United States)

    Nowamooz, Hossein; Masrouri, Farimah

    2009-11-01

    This Note presents an experimental study performed on expansive compacted loose and dense samples using osmotic oedometers. Several successive wetting and drying cycles were applied in a suction range between 0 and 8 MPa under different values of constant net vertical stress (15, 30, and 60 kPa). During the suction cycles, the dense samples showed cumulative swelling strains, while the loose samples showed volumetric shrinkage accumulation. At the end of the suction cycles, the volumetric strains converged to an equilibrium stage that indicated elastic behavior of the swelling soil for any further hydraulic variations. At this stage, the compression curves for the studied soil at the different imposed suctions (0, 2, and 8 MPa) converged towards the saturated state curve for the high applied vertical stresses. We defined this pressure as the saturation stress(P). The compression curves provided sufficient data to examine the soil mechanical behavior at the equilibrium stage. To cite this article: H. Nowamooz, F. Masrouri, C. R. Mecanique 337 (2009).

  6. Synthesis, Characterization and Swelling Characteristics of Graft Copolymerized Isotactic Polypropylene Film

    Directory of Open Access Journals (Sweden)

    Teena Sehgal

    2010-01-01

    Full Text Available Grafted membranes were prepared through chemical graft copolymerization of methyl methacrylate (MMA onto isotactic polypropylene film (IPP. The IPP films were grafted with MMA molecules resulting in IPP-g-MMA grafts using benzoyl peroxide as an initiator in an inert nitrogen atmosphere. Using this method, the degree of grafting and morphology could be controlled through the variation of reaction parameters such as initiator concentration, monomer concentration, reaction time, and the reaction temperature. Optimum conditions pertaining to maximum percentage of grafting (%G were evaluated as a function of these parameters. Maximum percentage of grafting (50% was obtained at [BPO]=0.03 M, [MMA]=10% V/V, and [Reaction Temperature] = 70∘C in a [Reaction time] of 120 minutes. IPP-g-MMA films were investigated for their swelling behavior. Water-swelling analysis of IPP-g-MMA was carried out as a function of different percentage of grafting, temperatures, and time. Maximum swelling percentage of IPP-g-MMA (92% was observed in 8 hours at 60∘C. The evidence of grafting was carried out by Fourier transform spectroscopy (FTIR, atomic force microscopy (AFM, and scanning electron microscopy (SEM before and after grafting, respectively. The swelling pattern was characterized by two distinct stages, an initial diffusion-controlled fast swelling, followed by a subsequent slower process controlled by the relaxation of polymer fragments. Swelling chrematistics of IPP-g-MMA make it a potentially useful material.

  7. Morphological effect on swelling behaviour of hydrogel

    Science.gov (United States)

    Yacob, Norzita; Hashim, Kamaruddin

    2014-02-01

    Hydrogels are hydrophilic polymer networks that are capable of imbibing large amounts of water. In this work, hydrogels prepared from natural and synthetic polymers were irradiated by using electron beam irradiation. The morphology of hydrogel inter-polymeric network (IPN) was investigated using Scanning Electron Microscopy (SEM). The studies reveal correlations between pore sizes of IPN with degree of cross-linking. This relation also has an effect on swelling properties of the hydrogel. The results indicated that hydrogel with smaller pore size, as a result of much dense IPN, would decrease water uptake capacity. Combination of natural and synthetic polymers to form hydrogel affects the pore size and swelling property of the hydrogel as compared to each component of polymer.

  8. The Attenuation of Swell Waves by Rain

    Science.gov (United States)

    Cavaleri, Luigi; Bertotti, Luciana

    2017-10-01

    Within the progressive improvement in wave modeling we focus on the attenuation of swell waves by rain. Till now ignored, the process is shown to be relevant, especially for the correct estimate of swell. Following the practical impossibility of devoted field experiments, we exploit the global model results over a period of more than four years to extract the tiny signal associated to the attenuation by rain. A direct comparison of the ratio model by altimeter significant wave heights versus the encountered rain amount hints to a marked related dependence. A proper quantification of the related physical effect requires a multiple step procedure that we describe in detail. We check the reliability of the results, and we provide the related source function ready for implementation in operational wave models.

  9. Morphological effect on swelling behaviour of hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Yacob, Norzita; Hashim, Kamaruddin [Radiation Processing Technology Division, Malaysian Nuclear Agency (NUKLEAR MALAYSIA) Bangi, 43000 Kajang (Malaysia)

    2014-02-12

    Hydrogels are hydrophilic polymer networks that are capable of imbibing large amounts of water. In this work, hydrogels prepared from natural and synthetic polymers were irradiated by using electron beam irradiation. The morphology of hydrogel inter-polymeric network (IPN) was investigated using Scanning Electron Microscopy (SEM). The studies reveal correlations between pore sizes of IPN with degree of cross-linking. This relation also has an effect on swelling properties of the hydrogel. The results indicated that hydrogel with smaller pore size, as a result of much dense IPN, would decrease water uptake capacity. Combination of natural and synthetic polymers to form hydrogel affects the pore size and swelling property of the hydrogel as compared to each component of polymer.

  10. Swelling Properties of Hydrogels Containing Phenylboronic Acids

    OpenAIRE

    Arum Kim; Mujumdar, Siddharthya K.; Siegel, Ronald A.

    2013-01-01

    Phenylboronic acids are a class of compounds that bind glucose and other sugars. When polymerized into hydrogels, they provide a convenient nonenzymatic means for sensing glucose concentration, provided competing sugars are present at negligible concentrations. In this paper we provide a comprehensive study of swelling of hydrogels containing methacrylamidophenylboronic acid (MPBA), as a function of pH and concentration of either glucose or fructose. In one set of hydrogels, MPBA is substitut...

  11. A Biophysical Model for Cytotoxic Cell Swelling.

    Science.gov (United States)

    Dijkstra, Koen; Hofmeijer, Jeannette; van Gils, Stephan A; van Putten, Michel J A M

    2016-11-23

    We present a dynamic biophysical model to explain neuronal swelling underlying cytotoxic edema in conditions of low energy supply, as observed in cerebral ischemia. Our model contains Hodgkin-Huxley-type ion currents, a recently discovered voltage-gated chloride flux through the ion exchanger SLC26A11, active KCC2-mediated chloride extrusion, and ATP-dependent pumps. The model predicts changes in ion gradients and cell swelling during ischemia of various severity or channel blockage with realistic timescales. We theoretically substantiate experimental observations of chloride influx generating cytotoxic edema, while sodium entry alone does not. We show a tipping point of Na(+)/K(+)-ATPase functioning, where below cell volume rapidly increases as a function of the remaining pump activity, and a Gibbs-Donnan-like equilibrium state is reached. This precludes a return to physiological conditions even when pump strength returns to baseline. However, when voltage-gated sodium channels are temporarily blocked, cell volume and membrane potential normalize, yielding a potential therapeutic strategy. Cytotoxic edema most commonly results from energy shortage, such as in cerebral ischemia, and refers to the swelling of brain cells due to the entry of water from the extracellular space. We show that the principle of electroneutrality explains why chloride influx is essential for the development of cytotoxic edema. With the help of a biophysical model of a single neuron, we show that a tipping point of the energy supply exists, below which the cell volume rapidly increases. We simulate realistic time courses to and reveal critical components of neuronal swelling in conditions of low energy supply. Furthermore, we show that, after transient blockade of the energy supply, cytotoxic edema may be reversed by temporary blockade of Na(+) channels. Copyright © 2016 the authors 0270-6474/16/3611881-10$15.00/0.

  12. Dimensional stability and anisotropy of SiC and SiC-based composites in transition swelling regime

    Science.gov (United States)

    Katoh, Yutai; Koyanagi, Takaaki; McDuffee, Joel L.; Snead, Lance L.; Yueh, Ken

    2018-02-01

    Swelling, or volumetric expansion, is an inevitable consequence of the atomic displacement damage in crystalline silicon carbide (SiC) caused by energetic neutron irradiation. Because of its steep temperature and dose dependence, understanding swelling is essential for designing SiC-based components for nuclear applications. In this study, swelling behaviors of monolithic CVD SiC and nuclear grade SiC fiber - SiC matrix (SiC/SiC) composites were accurately determined, supported by the irradiation temperature determination for individual samples, following neutron irradiation within the lower transition swelling temperature regime. Slightly anisotropic swelling behaviors were found for the SiC/SiC samples and attributed primarily to the combined effects of the pre-existing microcracking, fiber architecture, and specimen dimension. A semi-empirical model of SiC swelling was calibrated and presented. Finally, implications of the refined model to selected swelling-related issues for SiC-based nuclar reactor components are discussed.

  13. Water holding capacity and swelling of casein hydrogels

    NARCIS (Netherlands)

    de Kruif, C; Anema, Skelte G.; Zhu, Changjun; Havea, Palatasa; Coker, Christina

    2015-01-01

    The water holding capacity of casein gels was investigated by measuring the swelling and de-swelling under a variety of conditions of temperature and salt concentration. Transglutaminase cross-linked sodium caseinate (15% w/w) gels will swell in good solvents or shrink in poor solvents until an

  14. Kinetics of swelling-breakdown of a W/O/W multiple emulsion: possible mechanisms for the lipophilic surfactant effect.

    Science.gov (United States)

    Geiger, S; Tokgoz, S; Fructus, A; Jager-Lezer, N; Seiller, M; Lacombe, C; Grossiord, J L

    1998-03-02

    The properties and behavior of a W/O/W multiple emulsion formulation were analyzed during a swelling-breakdown process. Various experimental analyses, such as granulometry, rheology and conductimetry were performed, as well as a micropipette aspiration method. The predominant role of the lipophilic surfactant during the swelling phase confirmed. Two different mechanism can be proposed. Both imply the migration of the lipophilic surfactant from one interface to another and probably take place successively. The lipophilic surfactant could diffuse from the first to the second interface, thus rigidifying the membrane, or from the oily phase to the first interface, resulting in delayed coalescence of the aqueous droplets during swelling.

  15. The Future of Swelling Elastomers: An Elastomer Manufacturer's View of Swelling Elastomer Developments and Market Trends

    Directory of Open Access Journals (Sweden)

    R Seyger

    2013-06-01

    Full Text Available Swelling elastomers have gained acceptance as very effective products for creating sealing in various industries, including those creating energy from fossil fuels and geothermal resources. This paper outlines the research and development work being conducted not only in the application of these elastomers but also in the development work required to create new generations of elastomers. It touches on fundamental research into the mechanics of swelling with the intent to create a better and more predictable sealing as well as more advanced elastomers. It lifts the veil on the direction of work being done on new elastomers being developed in order to enable a better control of swelling. By doing so, the research is opening up field of applications for new equipment designs and mechanical possibilities in the future. Additionally, it addresses the need for a better and more in-depth dialogue between both chemical and mechanical engineers, and the elastomer companies and their customers on the potential that both swelling and non-swelling elastomers can offer to the industry as a whole.

  16. Crystal Crosslinked Gels with Aggregation-Induced Emissive Crosslinker Exhibiting Swelling Degree-Dependent Photoluminescence

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Oura

    2017-01-01

    Full Text Available The synthesis and photoluminescence properties of crystal crosslinked gels (CCGs with an aggregation-induced emission (AIE active crosslinker derived from tetraphenylethene (TPE is discussed in this article. The CCG was prepared from a metal organic framework (MOF with large pore aperture to allow the penetration of TPE crosslinker. The obtained CCG possessed a rectangular shape originated from the parent MOF, KUMOF. The CCG showed stimuli-responsive photoluminescence behavior depending on the swelling degree, thus the photoluminescence intensity was higher at higher swelling degree. By changing the solvent, water content, or ionic strength, the photoluminescence intensity was controllable, accompanying the change of swelling degree. Moreover, emission color tuning was also achieved by the introduction of luminescent rare earth ions to form a coordination bonding with residual carboxylate inside the CCG.

  17. Kinetics of dextran crosslinking by epichlorohydrin: a rheometry and equilibrium swelling study.

    Science.gov (United States)

    Emami Meybodi, Zahraalsadat; Imani, Mohammad; Atai, Mohammad

    2013-02-15

    Curing behavior and gel properties of dextran are investigated during its crosslinking by epichlorohydrin (ECH) using rheometry and equilibrium swelling studies. Each ECH/anhydroglucose unit of different molar ratio (0.16-0.99) was added to a known volume of aqueous dextran solution (25%, w/w) in the presence of sodium hydroxide (1.2-3.6 M) as a catalyst. Gel point was investigated as a function of the reactants concentration. The rheological behavior of the curing gels was evaluated using a rheokinetic model. Swelling behavior of the cured, cylindrical specimens was also studied gravimetrically. Increasing NaOH and ECH concentrations significantly increased the crosslinking reaction rate leading to shorter gel points, which was attributed to more ionization of hydroxyl functional groups of dextran due to higher NaOH concentrations. Degree of swelling vs. the reaction time was decreased sharply as a direct function of increasing NaOH and ECH concentrations up to certain levels, which then leveled off. In contrast, higher NaOH concentrations increased the swelling ratio probably due to the alkaline induced degradation of dextran chains. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qingguo, E-mail: qwang@qust.edu.cn [Key Laboratory of Rubber-Plastics of Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Shandong Provincial Key Laboratory of Rubber-Plastics, Qingdao 266042 (China); Zhou, Xue; Zeng, Jinxia; Wang, Jizeng [Key Laboratory of Rubber-Plastics of Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China)

    2016-02-01

    In this paper, the electron beam irradiation technology being more suitable for the industry application is explored to fabricate the acrylic acid (AAc) monomer-grafted polyvinyl alcohol (PVA-g-AAc) hydrogels. ATR-IR spectra of the PVA-g-AAc hydrogels shows an obvious absorption peak of the −C=O group at 1701 cm{sup −1}, indicating that the AAc monomers were grafted onto the PVA macromolecules. This paper also studied some effects of the mass ratio of PVA/AAc, pH of buffer solution and irradiation dosage on the water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels. The water swelling ratio of PVA-g-AAc hydrogels decreases with increased irradiation dosage and mass ratio of PVA/AAc, whereas swelling ratio increases with increased pH of buffer solution and soaking time. The water-swelling behavior of PVA-g-AAc hydrogels occurred easily in an alkaline environment, particularly in a buffer solution with pH 9.2. Both PVA-g-AAc hydrogels (PVA/AAc = 1/5, w/w) irradiated with 5 kilogray (kGy) and PVA-g-AAc hydrogels (PVA/AAc = 1/1, w/w) irradiated with 15 kGy could easily absorb water and lead to high water swelling ratios (up to about 600%), which are potential candidates to meet the requirements for some biomedical applications.

  19. Dielectric study of neutral and charged hydrogels during the swelling process

    Science.gov (United States)

    Yılmaz, Y.; Gelir, A.; Salehli, F.; Nigmatullin, R. R.; Arbuzov, A. A.

    2006-12-01

    Dielectric spectroscopy measurements of conductivity were applied for understanding the change in the internal morphology of the neutral and permanently charged polyacrylamide (PAAm) hydrogels during the swelling process. For the first time four distinct peaks (each corresponding to a different swelling stage) in the conductivity of the neutral gel were observed during the swelling of this gel. These peaks are related to the distribution of dense polymer regions (they are defined as the "blobs") appearing in a microstructure of the given PAAm gel having at least four average sizes. For the charged gel the heterogeneity decreases due to the internal electric field of the charged sites. Thus, this characteristic behavior in the conductivity becomes almost negligible for the gel charged with permanent SO3- groups. It seems this fact causes considerable decrease in amplitude of the peaks and overall decrease the conductivity during the whole swelling process especially at high frequencies. The new theory of dielectric relaxation based on the fractional kinetics containing the complex power-law exponents was used for verifying these swelling processes and received an excellent confirmation in description of the real part of the complex conductivity Re[σ(ω )] by the fitting function that follows from the suggested theory. The calculated power-law exponents describe the behavior of Re[σ(ω,m/m0)] in the available frequency range (30Hz-13MHz) and for all values of the relative masses (volumes) measured in the process of the experiment. The excellent coincidence between the new theory and measured data gives a possibility to suggest more reliable physical picture of the swelling process that takes place in neutral/charged gels.

  20. Refraction of swell by surface currents

    CERN Document Server

    Gallet, Basile

    2014-01-01

    Using recordings of swell from pitch-and-roll buoys, we have reproduced the classic observations of long-range surface wave propagation originally made by Munk et al. (1963) using a triangular array of bottom pressure measurements. In the modern data, the direction of the incoming swell fluctuates by about $\\pm 10^\\circ$ on a time scale of one hour. But if the incoming direction is averaged over the duration of an event then, in contrast with the observations by Munk et al. (1963), the sources inferred by great-circle backtracking are most often in good agreement with the location of large storms on weather maps of the Southern Ocean. However there are a few puzzling failures of great-circle backtracking e.g., in one case, the direct great-circle route is blocked by the Tuamoto Islands and the inferred source falls on New Zealand. Mirages like this occur more frequently in the bottom-pressure observations of Munk et al. (1963), where several inferred sources fell on the Antarctic continent. Using spherical ra...

  1. Giant cell arteritis presenting as facial swelling.

    Science.gov (United States)

    Ricketti, Anthony J; Cleri, Dennis J; Godyn, Janusz J; Shenk, Suzanne H; Vernaleo, John R

    2008-01-01

    Facial swelling is commonly ascribed to angioedema and a host of other causes. Temporal arteritis (TA), a disease most often diagnosed in patients over the age of 50 years, frequently presents with nonspecific and often ignored complaints (headache, symptoms of polymyalgia rheumatica, low-grade fever, fever of unknown origin, loss of appetite, depression, joint pains, weight loss, hair loss, and even respiratory symptoms). The diagnosis of TA is highly likely in the presence of new-onset headaches, polymyalgia rheumatica, and a tender, cord-like, or swollen temporal artery. Facial swelling must be appreciated as another presentation of TA, especially when accompanied by other nonspecific symptoms. High clinical suspicion, immediate treatment, and definitive diagnosis by temporal artery biopsy are necessary to prevent the most severe vascular complications of blindness and cerebrovascular accidents. Treatment with corticosteroids is most often successful. Because this treatment is fraught with all the risks of high-dose and prolonged steroid therapy, it should only be initiated in cases of significant clinical suspicion, followed by a timely temporal artery biopsy to confirm the diagnosis. Delay in therapy increases the risk of a vascular catastrophe. Delay in obtaining a temporal artery biopsy after therapy has been initiated decreases the diagnostic sensitivity of the test. Other modalities of immunosuppressive therapy remain either unsuccessful or unproven. Concomitant low-dose aspirin therapy appears to hold promise.

  2. High resolution interferometry as a tool for characterization of swelling of weakly charged hydrogels subjected to amphiphile and cyclodextrin exposure.

    Science.gov (United States)

    Gao, Ming; Gawel, Kamila; Stokke, Bjørn Torger

    2013-01-15

    A high resolution interferometric technique was used to determine swelling behavior of weakly charged polyacrylamide hydrogels in the presence of oppositely charged surfactants and subsequent exposure to cyclodextrins. Hydrogels of copolymerized acrylamide and 2-acrylamido-2-methyl-1-propanesulfonic acid (0.22, 0.44, 0.88 mol%) crosslinked with bisacrylamide (3, 6, 12 mol%) were employed. The equilibrium swelling and swelling kinetics of the hydrogels were determined with 2nm resolution of the optical length and sampled at approximately 1 Hz. These properties were determined for the hydrogels exposed to cationic surfactants dodecyltrimethylammonium bromide (DTAB) and cetyltrimethylammonium bromide (CTAB) at concentrations from 10(-7) up to 2×10(-3)M. The distribution of surfactant within one AAM-co-AMPSA hydrogel equilibrated in CTAB/perylene solution was investigated by confocal laser scanning microscopy. Hydrogels equilibrated at selected surfactant concentrations were subsequently exposed to cyclodextrins (α-CD, β-CD, methyl-β-CD and γ-CD) forming inclusion complexes with the surfactants. The results show different types of behavior for the two surfactants used, arising from the difference in the length of surfactant hydrophobic tail. The changes in the surfactant induced swelling of the hydrogels are suggested to arise from the net effect of electrostatic screening of sulfonic acid-amide group interactions and surfactant micellization. Hydrogels with the largest charge density and the lowest crosslink density yielded the most pronounced changes in swelling properties on exposure to DTAB or CTAB. The hydrogels displayed swelling kinetics on stepwise changes in surfactant concentrations that depended on the surfactant concentration range. The high resolution monitoring of hydrogel swelling associated with supramolecular complex formation in three-component systems hydrogel-amphiphilic molecule-cyclodextrin provides more details on the swelling behavior than

  3. Análise da influência do tratamento de purificação no comportamento de inchamento de argilas organofílicas em meios não aquosos Analysis of the influence of the purification treatment on the swelling behavior in non-aqueous media of organophilic clays

    Directory of Open Access Journals (Sweden)

    H. S. Ferreira

    2008-03-01

    Full Text Available As argilas bentonitas possuem importantes funções em fluidos de perfuração não aquosos. No entanto, impurezas presentes na argila e a escolha inadequada do sal quaternário utilizado no seu processo de organofilização podem comprometer a compatibilidade do sistema argila-fluido. Assim, este trabalho tem por objetivo analisar a influência do tratamento de purificação e dos sais quaternários de amônio no comportamento de inchamento de argilas organofílicas em meios não aquosos. A argila bentonita foi purificada através de procedimento de sedimentação e as argilas organofílicas foram preparadas utilizando-se cloreto de alquil benzil amônio (Dodigen, cloreto de diestearil dimetil amônio (Praepagen, cloreto de cetil trimetil amônio (Genamim e brometo de cetil trimetil amônio (Cetremide. As argilas organofilizadas foram caracterizadas por difração de raios X e determinação da distribuição do tamanho de partículas e, em seguida, submetidas ao ensaio de inchamento de Foster em éster, parafina e óleo diesel. Os resultados mostram que o processo de purificação foi eficiente na redução de impurezas presentes na bentonita e que a argila organofílica purificada tratada com Praepagen e Genamim apresenta valores de inchamento de Foster em éster, óleo diesel e parafina superiores aos obtidos com argilas organofílicas sem purificação (natural e comercial.Bentonite clays play important roles in oil based drilling fluids. However, clay impurities and the wrong choose of the quaternary ammonium salt used in the organophilization process can lead to organoclay-fluid low interactions. Thus, this work has as aim study the influence of the purification process and quaternary ammonium salts on the swelling behavior in oil media of organophilic clays. The bentonite clay was purified using a sedimentation process and organoclay were prepared using alkyl dimethyl benzyl ammonium chloride (Dodigen, distearyl dimethyl ammonium

  4. Effect of swelling mineral on geotechnical characteristics of clay soil

    Directory of Open Access Journals (Sweden)

    Mohammed Cherif Mechri

    2018-01-01

    Full Text Available The shrinking and swelling is a very common phenomenon in the world, mainly in arid and semiarid areas. The construction on these soils often requires a study of the risk of swelling, in advance. The emergence of this phenomenon in soils is caused primarily by the presence of swelling clays and water. The risk is most significant when the rate of the expansive minerals, such as bentonite, is important. Several researchers have studied the relationship between the percentages of swelling minerals and soil swelling potential. The researchers have shown the difficulty of characterization, because of the complexity of the phenomenon under natural conditions, where several other phenomena occur, and which are not considered in laboratory experimentation. This article addresses the characterization of several soils, with different swelling rates from the physical, chemical and mechanical tests. It shows the relationship between the quantity of swelling minerals and some site conditions, such as water content and consolidation stress, on the ability of soil to swell. This work aims to establish empirical relationships between the percentage of swelling minerals and soil swelling potential.

  5. Swelling of Superabsorbent Poly(Sodium-Acrylate Acrylamide) Hydrogels and Influence of Chemical Structure on Internally Cured Mortar

    Science.gov (United States)

    Krafcik, Matthew J.; Erk, Kendra A.

    Superabsorbent hydrogel particles show promise as internal curing agents for high performance concrete (HPC). These gels can absorb and release large volumes of water and offer a solution to the problem of self-dessication in HPC. However, the gels are sensitive to ions naturally present in concrete. This research connects swelling behavior with gel-ion interactions to optimize hydrogel performance for internal curing, reducing the chance of early-age cracking and increasing the durability of HPC. Four different hydrogels of poly(sodium-acrylate acrylamide) are synthesized and characterized with swelling tests in different salt solutions. Depending on solution pH, ionic character, and gel composition, diffrerent swelling behaviors are observed. As weight percent of acrylic acid increases, gels demonstrate higher swelling ratios in reverse osmosis water, but showed substantially decreased swelling when aqueous cations are present. Additionally, in multivalent cation solutions, overshoot peaks are present, whereby the gels have a peak swelling ratio but then deswell. Multivalent cations interact with deprotonated carboxylic acid groups, constricting the gel and expelling water. Mortar containing hydrogels showed reduced autogenous shrinkage and increased relative humidity.

  6. Angiosarcoma Presenting with Minor Erythema and Swelling

    Directory of Open Access Journals (Sweden)

    Catherine A. Cox

    2013-04-01

    Full Text Available A 76-year-old man presented with slowly progressive swelling in his forehead and left upper eyelid over the course of three months. CT scanning showed non-specific enhancement of subcutaneous tissues, suggesting a low-grade cellulitis. Poor response to treatment prompted an MRI, which revealed the presence of a soft tissue lesion. Biopsy of this lesion was positive for angiosarcoma. The patient underwent chemotherapy and radiation, but unfortunately succumbed to his malignancy eight months later. This case illustrates a rare example of facial/periorbital angiosarcoma, a benign-appearing but aggressive tumor associated with a high incidence of mortality. A review of the literature and current treatment options are discussed.

  7. Design and engineering of west-side revetment for Tachibana Bay Power Station. Swelling behavior of sand compaction pile improved ground and mechanical properties of composite ground; Tachibanawan hatsudensho Nishigogan koji no sekkei to seko. Sand compaction pile kairyo jiban no moriagari kyodo to fukugo jiban no rikigaku tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Kameda, S.; Hara, J.; Ozaki, S. [Shikoku Electric Power Co., Inc., Kagawa (Japan)

    1997-07-05

    This report covers a sand compaction pile (SCP) process performed for the improvement of the sea bottom along the west-side revetment of the power station where a 10-odd meter thick sedimentary layer of soft clayey soil exists. Since the sea is only 5m deep in this area, an engineering method is chosen capable of minimizing the swelling of the ground, and changes in the physical properties of the composite ground that may affect the stability of the revetment are investigated. In this report, an estimating equation is proposed for accurately predicting the swelling, including the additional swelling of the ground already swollen, to result from the SCP-assisted improvement of the ground and a description is given of changes in composite ground mechanical properties induced by the SCP-assisted engineering work. A `one-directional construction system with one block constituted of three spans` is contrived. Furthermore, an estimating technique taking into account the secondary swelling is proposed. As the result, the apparent swelling rate agrees very well with the actual swelling rate. An SCP method with its capability enhanced may be established by considering time-dependent changes in the mechanical properties of the clayey soil between piles and their impact on the safety factor. 4 refs., 13 figs., 3 tabs.

  8. The relation between composition and swelling in clays

    Science.gov (United States)

    Foster, Margaret D.

    1955-01-01

    The phenomenon of swelling is associated with the hydration of clays; however, all clays do not swell when hydrated. those of the kaolin group, for example, exhibit little or no swelling on hydration. Sodiwm montmoillonite, on the other hand, characteristically swells in water to many times its dry volume. Calcium and magnesium montmorillonite and the hydrous micas, or so called illites, fall between these two extremes in swelling properties, but are, in general, much closer to kaolinite than to sodium montmorillonite in their increase in volume on hydration. These differences in the swelling characteristics of different clays may be related to their chemical composition, to the kind and degree of isomorphous replacements in their structure, and to the amount and nature of their associated exchangeable cations. 

  9. Investigation on Swells of the East China Sea

    Science.gov (United States)

    Tao, Aifeng; Wu, Chao

    2017-04-01

    In the recent decades, more and more human activities, including different kinds of marine structures and large ships, have been present in the East China Sea. It is necessary to fasten our attentions on the marine safety issues, particularly on the extreme waves. Because it has been known that the density of extreme waves may increase with Typhoon in the future with the global climate changing. The extreme waves can be induced not only by Typhoon in summer, but also by East Asian cold waves in winter for this special sea area. And the swells also can be very dangerous because the swells may result in the resonance with floating structures, including the ships. Focusing on the investigation of swells in the East China Sea, the hindcast for waves in the past ten years will be performed by the numerical model Wave Watch III based on the historical climate data. The numerical calculation domain covers the whole North West Pacific. Then the swells will be separated and analyzed from the simulated wave fields. Both the characteristics and the generation mechanisms of the swells will be investigated. Particularly, the swells, which propagating across the Ryukyu chain from east to west, will be analyzed in details. We used the CCMP & Myers wind data to run the WW3 model and reproduced the global wave fields in 2010-2014. After separating swell and wind sea from mixed waves, we studied the spatial and temporal distribution of swell in East China Sea and the formation mechanism of swell in East China Sea.The significant wave heights of swells in the East China Sea are mainly distributed in the 0.1-2.5m, the interval with the highest frequency of occurrence is 0.1-0.5m, and the proportion is about 50%. The spectrum peak periods of swells are mainly distributed in the 4-15s, the interval with the highest frequency of occurrence is 9-15s., and the proportion is about 25%. In terms of spatial distribution swells increase gradually from the offshore to deep sea, and also

  10. Rheology and scaling behavior of swelling clay dispersions | Chaoui ...

    African Journals Online (AJOL)

    The microstructure and scaling of rheological properties of colloidal gels of bentonite investigated as a function of volume fraction and strength of interparticle interaction over a range of volume fractions, elastic modulus is well described with a scaling law functions of volume fractions, while the role of interparticle attractions ...

  11. Modeling on swelling behavior of a confined polymer network

    NARCIS (Netherlands)

    Li, X.; Shen, Zhou; He, T.; Wessling, Matthias

    2008-01-01

    Polymeric membranes suffer from plasticization in gas separation, extensive swollen in pervaporation, nanofiltration, and fuel cells by losing performance. Growing research has experimentally realized that the membrane performance could be stabilized by blending with inert second polymer or

  12. Numerical Simulation Of The Treatment Of Soil Swelling Using Grid Geocell Columns

    Directory of Open Access Journals (Sweden)

    Fattah Mohammed Y.

    2015-06-01

    Full Text Available In this paper, a method for the treatment of the swelling of expansive soil is numerically simulated. The method is simply based on the embedment of a geogrid (or a geomesh in the soil. The geogrid is extended continuously inside the volume of the soil where the swell is needed to be controlled and orientated towards the direction of the swell. Soils with different swelling potentials are employed: bentonite base-Na and bentonite base-Ca samples in addition to kaolinite mixed with bentonite. A numerical analysis was carried out by the finite element method to study the swelling soil's behavior and investigate the distribution of the stresses and pore water pressures around the geocells beneath the shallow footings. The ABAQUS computer program was used as a finite element tool, and the soil is represented by the modified Drucker-Prager/cap model. The geogrid surrounding the geocell is assumed to be a linear elastic material throughout the analysis. The soil properties used in the modeling were experimentally obtained. It is concluded that the degree of saturation and the matric suction (the negative pore water pressure decrease as the angle of friction of the geocell column material increases due to the activity of the sand fill in the dissipation of the pore water pressure and the acceleration of the drainage through its function as a drain. When the plasticity index and the active depth (the active zone is considered to be equal to the overall depth of the clay model increase, the axial movement (swelling movement and matric suction, as a result of the increase in the axial forces, vary between this maximum value at the top of the layer and the minimum value in the last third of the active depth and then return to a consolidation at the end of the depth layer.

  13. Anisotropic swelling observed during stress-free reirradiation of AISI 304 tubes previously irradiated under stress

    Energy Technology Data Exchange (ETDEWEB)

    Gamer, F. [Pacific Northwest National Laboratory, P.O. Box 999, Richland WA, AK 99352 (United States); Flinn, J.E. [Argonne National Laboratory, EBR-II Project, Idaho Falls Ill, AK (United States); Hall, M.M. [Bechtel Bettis Company, West Mifflin, PA, AK (United States)

    2007-07-01

    Full text of publication follows: Structural steels anticipated for fusion applications will experience time-dependent changes in the radiation environment, i.e. stress level, stress state, irradiation temperature and dpa rate. There are insufficient data available to allow confident prediction of the effects of such environmental changes on subsequent behavior of swelling and irradiation creep. Data on the effect of changes in stress state or irradiation temperature are especially lacking. In this paper are presented the results of a reirradiation experiment conducted in EBR-II. Cladding tubes constructed from 304L stainless steel were removed from irradiated metal-driver fuel elements. These tubes were stressed during irradiation by fission gas buildup and fuel clad mechanical interaction. After cutting and cleaning, the density and diameter changes of each section were measured to determine swelling and irradiation creep. The tubes sections were re-irradiated in the absence of stress to 10 dpa, followed by measurement of their density and changes in both diameter and length. Also irradiated beside the previously stressed specimens were adjacent tube sections of 304L that encapsulated the fuel pins during the original irradiation. The cladding-capsule pairs experienced the same flux-spectral exposures, but the capsules were stress-free and operating at {approx}50 deg. C lower temperatures. Tube pairs were irradiated at either the original irradiation temperature or at significantly different temperatures. The first major conclusion is that once significant swelling was reached in the initial irradiation, the swelling continued thereafter without changing in response to temperature or stress changes, approaching or reaching {approx}1%/dpa. The second major conclusion is that the previously-stressed material retained a memory of its earlier stress state, swelling in absence of stress with an anisotropic distribution of strains. The swelling of the previously

  14. Relationship between swelling of hydroxypropylmethylcellulose and the Hansen and Karger partial solubility parameters.

    Science.gov (United States)

    Navarro-Lupión, Francisco-Javier; Bustamante, Pilar; Escalera, Begoña

    2005-07-01

    A model that relates the equilibrium swelling of hydroxypropylmethylcellulose to the partial solubility parameters of both the polymer and the solvents is proposed to interpret and correlate the experimental data. The non-specific interactions are expressed as the dispersion delta(d) and polar delta(p) solubility parameters of Hansen, or as a combination of both. Hydrogen bonding is represented by the acidic delta(a) and the basic delta(b) Karger solubility parameters. The results are compared with models including the same parameters for non-specific interactions (delta(d) and delta(p)) and the Hansen hydrogen bonding parameter delta(h). Equilibrium swelling of this hydrophilic polymer that is widely used in drug formulation is measured in pure solvents covering a wide polarity range. In a qualitative way, swelling increases in solvents with higher Hildebrand solubility parameters and stronger hydrogen bonding capability, and it decreases in non-polar solvents. Single polarity indexes, such as the Hildebrand solubility parameter or the partition coefficient (PC), do not fit well the overall experimental data. The best correlations were obtained with the proposed model, providing at the same time an interpretation consistent with the physical meaning of the terms included in the equation. Swelling increases as the non-specific interactions of the polymer and the solvents become alike, and as the Lewis acid-base interactions of the polymer (1) and the solvent (2) represented by the products delta(1a)delta(2b) and delta(1b)delta(2a) become greater. Conversely, hydrogen bonding self association of the solvents (the product delta(1a)delta(1b)) lowers swelling. The results show that the Karger hydrogen bonding parameters provide a better approach than the Hansen hydrogen bonding parameter to correlate the swelling behavior of a hydrophilic polymer. (c) 2005 Wiley-Liss, Inc.

  15. Intraplate seismicity across the Cape Verde swell

    Science.gov (United States)

    Vales, Dina; Matias, Luís.; Haberland, Christian; Silveira, Graça.; Weber, Michael; Carrilho, Fernando; Dias, Nuno

    2010-05-01

    The Cape Verde Archipelago ((15-17°N, 23-26°W) is located within the African plate, about 500km west of Senegal, in the African coast. The islands are located astride the Cape Verde mid-plate topographic swell, one of the largest features of its type in the world's ocean basins. The origin of this Cape Verde swell is still in debate. Previous determinations of the elastic thickness (Te) reveal a normal Te and a modest heat flow anomaly which suggest that the swell cannot be fully explained by uplift due to thermal reheating of the lithosphere by an underlying ‘‘hot spot'' and that other, deep-seated, mantle processes must be involved. The CV-PLUME (An investigation on the geometry and deep signature of the Cape Verde mantle plume) project intends to shape the geometry and deep origin of the Cape Verde mantle plume, via a combined study of seismic, magnetic, gravimetric and geochemical observations. Through this study we intend to characterize the structure beneath the archipelago from the surface down to the deep mantle. The core of this 3-year project was a temporary deployment of 39 Very Broad Band seismometers, across all the inhabited islands, to recorder local and teleseismic earthquakes. These instruments were operational from November 2007 to September 2008. In this work we report on the preliminary results obtained from the CV-PLUME network on the characterization of the local and regional seismicity. To detect the small magnitude seismic events the continuous data stream was screened using spectrograms. This proved to be a very robust technique in the face of the high short-period noise recorded by many of the stations, particularly during day time. The 10 month observation time showed that the background seismic activity in the Archipelago and surrounding area is low, with only a very few events recorded by the complete network. However, two clusters of earthquakes were detected close to the Brava Island, one to the NW and a second one, more active

  16. Swelling in light water reactor internal components: Insights from computational modeling

    Energy Technology Data Exchange (ETDEWEB)

    Stoller, Roger E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Barashev, Alexander V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States); Golubov, Stanislav I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-01

    A modern cluster dynamics model has been used to investigate the materials and irradiation parameters that control microstructural evolution under the relatively low-temperature exposure conditions that are representative of the operating environment for in-core light water reactor components. The focus is on components fabricated from austenitic stainless steel. The model accounts for the synergistic interaction between radiation-produced vacancies and the helium that is produced by nuclear transmutation reactions. Cavity nucleation rates are shown to be relatively high in this temperature regime (275 to 325°C), but are sensitive to assumptions about the fine scale microstructure produced under low-temperature irradiation. The cavity nucleation rates observed run counter to the expectation that void swelling would not occur under these conditions. This expectation was based on previous research on void swelling in austenitic steels in fast reactors. This misleading impression arose primarily from an absence of relevant data. The results of the computational modeling are generally consistent with recent data obtained by examining ex-service components. However, it has been shown that the sensitivity of the model s predictions of low-temperature swelling behavior to assumptions about the primary damage source term and specification of the mean-field sink strengths is somewhat greater that that observed at higher temperatures. Further assessment of the mathematical model is underway to meet the long-term objective of this research, which is to provide a predictive model of void swelling at relevant lifetime exposures to support extended reactor operations.

  17. Swelling kinetics of microgels embedded in a polyacrylamide hydrogel matrix.

    Science.gov (United States)

    Huang, Na; Guan, Ying; Zhu, X X; Zhang, Yongjun

    2014-06-23

    Composite hydrogels--macroscopic hydrogels with embedded microgel particles--are expected to respond to external stimuli quickly because microgels swell much faster than bulky gels. In this work, the kinetics of the pH-induced swelling of a composite hydrogel are studied using turbidity measurements. The embedded microgel is a pH- and thermosensitive poly(N-isopropylacrylamide-co-acrylic acid) microgel and the hydrogel matrix is polyacrylamide. A rapid pH-induced swelling of the embedded microgel particles is observed, confirming that composite hydrogels respond faster than ordinary hydrogels. However, compared with the free microgels, the swelling of the embedded microgel is much slower. Diffusion of OH(-) into the composite hydrogel film is identified as the main reason for the slow swelling of the embedded microgel particles, as the time of the pH-induced swelling of this film is comparable to that of OH(-) diffusion into the film. The composition of the hydrogel matrix does not significantly change the characteristic swelling time of the composite hydrogel film. However, the swelling pattern of the film changes with composition of the hydrogel matrix. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Effect of crosslinker on the swelling and adsorption properties of ...

    Indian Academy of Sciences (India)

    [3], such as diapers, female sanitary napkins, adult incon- tinence products and as a material for improving the water retention capacity of soil [4]. The SAPs made of ionic mono- meric units can be used to adsorb oppositely charged species like heavy metal ions and dyes from waste water [5,6]. The swelling and de-swelling ...

  19. Spectral partitioning and swells in the black sea

    NARCIS (Netherlands)

    van Vledder, G.P.; Akpınar, Adem

    2016-01-01

    The swell climate of the Black Sea has been determined using a long-term 31-year wave hindcast with the thirdgeneration spectral wave model SWAN in combination with spectral partitioning. This technique enables decomposing wave spectra into individual wave systems representing wind seas or swells

  20. Ocean swell within the kinetic equation for water waves

    Directory of Open Access Journals (Sweden)

    S. I. Badulin

    2017-06-01

    Full Text Available Results of extensive simulations of swell evolution within the duration-limited setup for the kinetic Hasselmann equation for long durations of up to 2  ×  106 s are presented. Basic solutions of the theory of weak turbulence, the so-called Kolmogorov–Zakharov solutions, are shown to be relevant to the results of the simulations. Features of self-similarity of wave spectra are detailed and their impact on methods of ocean swell monitoring is discussed. Essential drop in wave energy (wave height due to wave–wave interactions is found at the initial stages of swell evolution (on the order of 1000 km for typical parameters of the ocean swell. At longer times, wave–wave interactions are responsible for a universal angular distribution of wave spectra in a wide range of initial conditions. Weak power-law attenuation of swell within the Hasselmann equation is not consistent with results of ocean swell tracking from satellite altimetry and SAR (synthetic aperture radar data. At the same time, the relatively fast weakening of wave–wave interactions makes the swell evolution sensitive to other effects. In particular, as shown, coupling with locally generated wind waves can force the swell to grow in relatively light winds.

  1. The Swelling Behaviour of Polystyrene (PS)/ Polyvinylacetate (Pvac ...

    African Journals Online (AJOL)

    The effect of the variation of the type of solvent responsible for the differences in the swelling kinetics of Polystyrene (PS) and Polyvinyl acetate (PVAc) blends was studied. The results showed that the nature of solvent control or affects the degree of swelling. Also, 1-V characteristics at temperature range of 323-363K shows ...

  2. Amylograph Pasting Properties And Swelling Power Of Six Varieties ...

    African Journals Online (AJOL)

    The Amylograph pasting properties and swelling power of starch extracted from six varieties of cowpea were studied. Significant differences (P ≤ 0.05) were found in starch pasting properties and swelling power. Non-distinct peak viscosities characterized starches. The hot paste viscosity at 95oC ranged between 880 ...

  3. Swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite under salinization-desalinization cycle conditions

    OpenAIRE

    Chen, Yong-gui; Zhu, Chunming; YE, Wei-Min; Wang, Qiong; Cui, Yu-Jun

    2015-01-01

    Compacted bentonite has been used as buffer material in radioactive waste disposal. Once compacted bentonite is emplaced, the chemical composition of site water is changed due to the long-term interaction between the bentonite, surrounding rock and the concrete facility; therefore the hydraulic mechanical behavior of compacted bentonite should be evaluated for the disposal safety. In this study, the swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite were investigated un...

  4. Thyroid swellings in the art of the Italian Renaissance.

    Science.gov (United States)

    Sterpetti, Antonio V; De Toma, Giorgio; De Cesare, Alessandro

    2015-09-01

    Thyroid swellings in the art of the Italian Renaissance are sporadically reported in the medical literature. Six hundred paintings and sculptures from the Italian Renaissance, randomly selected, were analyzed to determine the prevalence of personages with thyroid swellings and its meaning. The prevalence of personages with thyroid swellings in the art of Italian Renaissance is much higher than previously thought. This phenomenon was probably secondary to iodine deficiency. The presence of personages with thyroid swelling was related to specific meanings the artists wanted to show in their works. Even if the function and the role of the thyroid were discovered only after thyroidectomy was started to be performed, at the beginning of the 19th century, artists of the Italian Renaissance had the intuition that thyroid swellings were related to specific psychological conditions. Artistic intuition and sensibility often comes before scientific demonstration, and it should be a guide for science development. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Thermal expansion and swelling of cured epoxy resin used in graphite/epoxy composite materials

    Science.gov (United States)

    Adamson, M. J.

    1980-01-01

    The paper presents results of experiments in which the thermal expansion and swelling behavior of an epoxy resin system and two graphite/epoxy composite systems exposed to water were measured. It was found that the cured epoxy resin swells by an amount slightly less than the volume of the absorbed water and that the swelling efficiency of the water varies with the moisture content of the polymer. Additionally, the thermal expansion of cured epoxy resin that is saturated with water is observed to be more than twice that of dry resin. Results also indicate that cured resin that is saturated with 7.1% water at 95 C will rapidly increase in moisture content to 8.5% when placed in 1 C water. The mechanism for this phenomenon, termed reverse thermal effect, is described in terms of a slightly modified free-volume theory in conjunction with the theory of polar molecule interaction. Nearly identical behavior was observed in two graphite/epoxy composite systems, thus establishing that this behavior may be common to all cured epoxy resins.

  6. Investigation of the rheological properties and die swell of polylactic acid/nanoclay composites in a capillary rheometer

    Science.gov (United States)

    Dangtungee, R.; Petcharoen, K.; Pinijsattawong, K.; Siengchin, S.

    2012-01-01

    The purpose of this research was to investigate the rheological behavior and extrudate swell of polylactic acid (PLA) filled with a nanoclay. The effects of the amount of nanoclay and surface treatment were studied by a capillary rheometer. The dispersion of the nanoclay was inspected by using the scanning electron microscopy. Generally, PLA/nanoclay composites exhibited a pseudoplastic rheological behavior as the shear stress and die swell increased with increasing shear rate. However, the shear viscosity decreased. The die swell also increased with increasing shear stress. The elongation viscosity decreased with increasing elongation rate. The incorporation of nanoclay decreased the shear stress and shear viscosity to a lesser degree than the elongation viscosity.

  7. Influences of neutralization of superabsorbent hydrogel from hydroxyethyl cellulose on water swelling capacities

    Science.gov (United States)

    Adair, Ajaman; Klinpituksa, Pairote; Kaesaman, Azizon

    2017-08-01

    In this research, superabsorbent hydrogels were synthesized by graft copolymerization of hydroxyethyl cellulose (HEC) and polyacrylamide (PAM) under the initiation of potassium persulfate (KPS). The polymer networks were constructed using N,N'-methylenebisacrylamide (MBA), and the reaction was performed in an aqueous solution. The extent of grafting products was evaluated form grafting efficiency (%GE) and percentage of add-ons at HEC/AM ratios of 1: 10. The water swelling capacities, in terms of swelling capacity and weight loss, of resultant superabsorbent polymers (SAPs) after solvent extraction were determined for swelling behaviors. The result showed that the SAP had poor water absorption of approximately up to 23 g/g. To enhance swelling capacity of SAPs, an alkaline hydrolysis was done by using two types of alkaline bases, i.e., 2 M NaOH and 2 M KOH solution. The obtained treatment SAPs were neutralized by washing with distilled water and 0.5 M HCl until the liquors pH was nearly 7. They were found that the treatment SAPs showed the highest water absorption up to 317 g/g. Influences of various fluids pH values ranging between 4 and 10, on water swelling capacities of SAPs were also investigated. Under optimal pH value, the highest water absorptions of SAP was 382 g/g. To confirm the grafting reaction of PAM onto HEC backbone, FT-IR analysis was used. The results revealed absorption bands of the HEC backbone and new absorption bands from the grafted copolymer. Furthermore, the FT-IR spectrum was proved that washing with distilled water can alter the chemical functional group of SAPs.

  8. Simulation of PVT and swelling experimental data: a systematic evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Paulo S.M.V. [PETROBRAS S.A., Salvador, BA (Brazil). Unidade de Negocios da Bahia]. E-mail: psrocha@petrobras.com.br; Alves, Danilo C.R.; Sacramento, Vinicio S.; Costa, Gloria M.N. [Universidade Salvador (UNIFACS), Salvador, BA (Brazil). Centro de Estudos em Petroleo e Gas Natural (CEPGN)]. E-mail: gloria.costa@unifacs.br

    2004-07-01

    Accurate data of the phase behavior of oil and gas mixtures are needed, for example, for the design of process plants and reservoir simulation studies. Often, experimental PVT data are available, but in practice a few PVT measurements are carried out for a given mixture. Therefore, it is necessary to use a thermodynamic model when planning production strategies for a given petroleum reservoir. This raises the question of what accuracy can be obtained using a cubic equation of state for phase equilibrium calculations, for example at conditions in which oil and gas are being produced. The only way to improve the agreement between measured and calculated results is to adjust the equation of state parameters. Currently, there is not a clear methodology to make these modifications. The objective of this study is to investigate the best tuning to describe the PVT experimental data: differential liberation, constant composition expansion and swelling test. The following programs were used: SPECS and MI-PVT (Technical University of Denmark) and WinProp (windows version of CMGPROP). The Soave-Redlich-Kwong equation of sate was also used. Experimental data for 06 oil samples from Reconcavo Basin (Bahia- Brazil) were obtained in the CEPGN (Study Center on Oil and Natural Gas at UNIFACS) and used in the tuning (author)

  9. Anomalous swelling of multilamellar lipid bilayers in the transition region by renormalization of curvature elasticity

    DEFF Research Database (Denmark)

    Callisen, Thomas Hønger; Mortensen, Kell; Ipsen, John Hjorth

    1994-01-01

    Small-angle neutron scattering is used to determine the temperature dependence of the lamellar repeat distance in an aqueous multilamellar solution of phospholipid bilayers. A thermal anomaly in the swelling behavior is observed at the bilayer phase transition. The anomalous behavior can be suppr...... be suppressed by varying the lipid acyl-chain length or by alloying with a molecular stiffening agent. The experimental results are explained in terms of renormalization of the bilayer curvature elasticity and by using a theory of repulsive interlamellar undulation forces....

  10. Lymphangioma of epidydimis: An extremely rare cause of scrotal swelling

    Directory of Open Access Journals (Sweden)

    K K Pai

    2006-01-01

    Full Text Available Lymphangioma of epidydimis is a very rare cause of scrotal swelling. We report a case of lymphangioma of epidydimis in a 24 year old male. This case is being presented in view of its rarity.

  11. Postoperative Submandibular Gland Swelling following Craniotomy under General Anesthesia

    Directory of Open Access Journals (Sweden)

    Haruka Nakanishi

    2015-01-01

    Full Text Available Objective. Reporting of a rare case of postoperative submandibular gland swelling following craniotomy. Case Report. A 33-year-old male underwent resection for a brain tumor under general anesthesia. The tumor was resected via a retrosigmoid suboccipital approach and the patient was placed in a lateral position with his face down and turned to the right. Slight swelling of the right submandibular gland was observed just after the surgery. Seven hours after surgery, edematous change around the submandibular gland worsened and he required emergent reintubation due to airway compromise. The cause of submandibular gland swelling seemed to be an obstruction of the salivary duct due to surgical positioning. Conclusion. Once submandibular swelling and edematous change around the submandibular gland occur, they can worsen and compromise the air way within several hours after operation. Adequate precaution must be taken for any predisposing skull-base surgery that requires strong cervical rotation and flexion.

  12. Identification of Swell in Nearshore Surface Wave Energy Spectra

    Directory of Open Access Journals (Sweden)

    Paul A. Work

    2010-06-01

    Full Text Available An approach for routine identification of swell and sea in nominally fully developed, omnidirectional, surface water wave energy spectra measured in arbitrary water depth is developed, applied, and discussed. The methodology is an extension of earlier work with deepwater spectra and involves identifying the frequency at which wave steepness is maximized and relating this to the swell separation frequency. The TMA parameterized spectrum is employed to establish a relationship between the two frequencies so that the methodology can be used when wind data are unavailable. The methodology is developed for finite water depth and tested using a dataset that includes both acoustic Doppler current profiler and wave buoy data, recorded simultaneously at the same location. For cases where the sea and swell are clearly, visually distinguishable in the omnidirectional spectra, the new method accurately distinguishes between the two, but it can also be used to identify sea and swell in unimodal spectra.

  13. Lipid diffusion and swelling in a phase separated biocompatible thermoplastic elastomer.

    Science.gov (United States)

    Fittipaldi, Mauro; Grace, Landon R

    2016-12-01

    Lipid uptake was analyzed via gravimetric measurements in a biocompatible poly(styrene-block-isobutylene-block-styrene) (SIBS) copolymer. Absorption followed Fickian diffusion behavior very closely, although some deviation was noticed once saturation was reached. Diffusion parameters of three different SIBS formulations were calculated and used to predict the behavior of a fourth type based on molecular weight and relative polystyrene content. SIBS with lower polystyrene content and molecular weight showed lower physical stability and developed surface cracks that propagated with exposure to the lipid medium. Saturation lipid content varied from 45% to 63% by weight and was inversely related to polystyrene content, suggesting most of the plasticization is occurring in the isobutylene phase of SIBS. Moreover, swelling of specimens was monitored throughout the immersion in the lipid medium and ranged from 32% to 58%. Swelling in formulations with lower hard phase (polystyrene) was significantly higher than the swelling in SIBS with higher hard phase content. This is consistent with lipid-induced plasticization occurring in the soft (polyisobutylene) segments, relaxing the polymer network and leading to increased swelling and lipid uptake. The biocompatibility and tailorability of SIBS through control of hard/soft phase ratio offer significant advantages for in vivo applications. However, the lipophilic nature of the material and the associated degradation may render the polymer unusable in certain applications. The predictive model of lipid uptake introduced here will allow more accurate evaluation of lipid susceptibility during the preliminary design phase of SIBS-based in vivo structures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Transient instabilities in the swelling dynamics of a hydrogel sphere

    Science.gov (United States)

    Curatolo, Michele; Nardinocchi, Paola; Puntel, Eric; Teresi, Luciano

    2017-10-01

    We investigate the swelling dynamics driven by solvent absorption in a hydrogel sphere immersed in a solvent bath, through a computational model and a numerical study. We extensively describe the transient process from dry to wet and discuss the onset of surface instabilities through a measure of the lack of smoothness of the outer surface and a morphological pattern of that surface with respect to the two material paremeters driving the swelling dynamics.

  15. Lepromatous leprosy presenting as a swelling in the neck

    Directory of Open Access Journals (Sweden)

    Dogra Devraj

    1999-01-01

    Full Text Available A 25-year-old electrician presented with gradually, asymptomatic swelling on left of the neck since 2 years. The swelling which was initially diagnosed as cervical lymphadenitis by the internist represented the enlarged left great auricular nerve. Cutaneous examination revealed an ill-defined, hypoaesthetic macule with minimal atrophy on the pinna of the left ear. The histopathology of the nerve showed a lepromatous neuritis with bacteriological index (BI of 5+.

  16. Exaggerated sexual swellings and male mate choice in primates: testing the reliable indicator hypothesis in the Amboseli baboons.

    Science.gov (United States)

    Fitzpatrick, Courtney L; Altmann, Jeanne; Alberts, Susan C

    2015-06-01

    The paradigm of competitive males vying to influence female mate choice has been repeatedly upheld, but, increasingly, studies also report competitive females and choosy males. One female trait that is commonly proposed to influence male mate choice is the exaggerated sexual swelling displayed by females of many Old World primate species. The reliable indicator hypothesis posits that females use the exaggerated swellings to compete for access to mates, and that the swellings advertise variation in female fitness. We tested the two main predictions of this hypothesis in a wild population of baboons (Papio cynocephalus). First, we examined the effect of swelling size on the probability of mate-guarding ('consortship') by the highest-ranking male and the behavior of those males that trailed consorshipts ('follower males'). Second, we asked whether a female's swelling size predicted several fitness measures. We found that high-ranking males do not prefer females with larger swellings (when controlling for cycle number and conception) and that females with larger swellings did not have higher reproductive success. Our study-the only complete test of the reliable indicator hypothesis in a primate population-rejects the idea that female baboons compete for mates by advertising heritable fitness differences. Furthermore, we found unambiguous evidence that males biased their mating decisions in favor of females who had experienced more sexual cycles since their most recent pregnancy. Thus, rather than tracking the potential differences in fitness between females, male baboons appear to track and target the potential for a given reproductive opportunity to result in fertilization.

  17. Molecular Mechanisms Involved in Tissue Swelling due to Injury and due to Exposure to Low Temperature and Massive Water and Electrolyte Loss in Diarrheal Disorders.

    Science.gov (United States)

    1981-06-01

    confronting the conventional membrane-pump theory of the living cell concerns the swelling and shrinkage behavior. The great diffi- culty lies in the...shrink and swell in hyper- and hypotonic solutions when the polymer water system is enclosed in a regular dialysis tubing which is fully permeable to...the more concentrated salt solution. Dialysis tubing used is readily permeable to sodium citrate and are used only to hold the polymers. The data

  18. Swelling packer technology : case histories in open hole

    Energy Technology Data Exchange (ETDEWEB)

    Wilkens, A. [Easywell, Woodlands, TX (United States)

    2005-07-01

    This paper presented case histories of swelling packer technology open hole innovations. Challenges such as fluid flow management and the restriction of solids entering the well bore were discussed. Other challenges included the need to reduce well construction costs, long-term reliability, production optimization methods and positive economic returns. In order to simplify production methods, minimize pay zone damage and eliminate moving parts, it is advisable to return to the simpler open hole well-bore method. Zonal isolation issues were discussed. The role of oil swelling packer was described with reference to its flexibility attributes such as the fact that rubber swells in hydrocarbons, activates in oil but not pure water, and creates an effective seal in open hole. Swell packer for oil-based mud was examined, along with details of successful applications. Functionality issues were discussed. The advantages of swell pack for oil-based mud is that it is rugged, self-repairing and has no environmental impact. It also has a good track record and is more flexible than concrete, more durable than Hydrogenated Nitrile Butadiene Rubber (HNBR) and regains integrity after failure. Various well construction advances, completion advances and global installations were discussed. Reservoir, well construction and completion challenges were reviewed. Economic challenges were discussed. Various features of the Constrictor swell packer, which enables annular fluid flow management, were presented. The Oil Selector, a product that enables automatic water control, was also reviewed. 7 figs.

  19. Stepwise swelling of a thin film of lamellae-forming poly(styrene-b- butadiene) in cyclohexane vapor

    KAUST Repository

    Di, Zhenyu

    2012-06-26

    We investigated the swelling of a thin film of lamellae-forming poly(styrene-b-butadiene) in cyclohexane vapor. The vapor pressure and thus the degree of swelling of the film are increased in a stepwise manner using a custom-built sample cell. The resulting structural changes during and after each step were followed in situ using time-resolved grazing-incidence small-angle X-ray scattering (GISAXS). During the first step, the lamellar thickness increases strongly, before it decreases again. At the same time, the full width at half-maximum (FWHM) of the diffuse Bragg reflection along the film normal has a sharp maximum. These observations point to the formation of new lamellae. During the subsequent swelling steps, the lamellar thickness overshoots only weakly. The behavior thus resembles qualitatively our previous results on a similar thin film during swelling in saturated vapor of cyclohexane; however, it deviates from earlier theoretical predictions. We propose a theory that is quantitatively correct for the description of the dependence of the lamellar thickness on the polymer volume fraction in the late stage of the swelling steps. © 2012 American Chemical Society.

  20. Hypotonic swelling promotes nitric oxide release in cardiac ventricular myocytes: impact on swelling-induced negative inotropic effect.

    Science.gov (United States)

    Gonano, Luis Alberto; Morell, Malena; Burgos, Juan Ignacio; Dulce, Raul Ariel; De Giusti, Verónica Celeste; Aiello, Ernesto Alejandro; Hare, Joshua Michael; Vila Petroff, Martin

    2014-12-01

    Cardiomyocyte swelling occurs in multiple pathological situations and has been associated with contractile dysfunction, cell death, and enhanced propensity to arrhythmias. We investigate whether hypotonic swelling promotes nitric oxide (NO) release in cardiomyocytes, and whether it impacts on swelling-induced contractile dysfunction. Superfusing rat cardiomyocytes with a hypotonic solution (HS; 217 mOsm), increased cell volume, reduced myocyte contraction and Ca(2+) transient, and increased NO-sensitive 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM) fluorescence. When cells were exposed to HS + 2.5 mM of the NO synthase inhibitor l-NAME, cell swelling occurred in the absence of NO release. Swelling-induced NO release was also prevented by the nitric oxide synthase 1 (NOS1) inhibitor, nitroguanidine, and significantly reduced in NOS1 knockout mice. Additionally, colchicine (inhibitor of microtubule polymerization) prevented the increase in DAF-FM fluorescence induced by HS, indicating that microtubule integrity is necessary for swelling-induced NO release. The swelling-induced negative inotropic effect was exacerbated in the presence of either l-NAME, nitroguandine, the guanylate cyclase inhibitor, ODQ, or the PKG inhibitor, KT5823, suggesting that NOS1-derived NO provides contractile support via a cGMP/PKG-dependent mechanism. Indeed, ODQ reduced Ca(2+) wave velocity and both ODQ and KT5823 reduced the HS-induced increment in ryanodine receptor (RyR2, Ser2808) phosphorylation, suggesting that in this context, cGMP/PKG may contribute to preserve contractile function by enhancing sarcoplasmic reticulum Ca(2+) release. Our findings suggest a novel mechanism for NO release in cardiomyocytes with putative pathophysiological relevance determined, at least in part, by its capability to reduce the extent of contractile dysfunction associated with hypotonic swelling. Published on behalf of the European Society of Cardiology. All rights reserved. © The

  1. Aging and Embrittlement of High Fluence Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Was, gary; Jiao, Zhijie; der ven, Anton Van; Bruemmer, Stephen; Edwards, Dan

    2012-12-31

    Irradiation of austenitic stainless steels results in the formation of dislocation loops, stacking fault tetrahedral, Ni-Si clusters and radiation-induced segregation (RIS). Of these features, it is the formation of precipitates which is most likely to impact the mechanical integrity at high dose. Unlike dislocation loops and RIS, precipitates exhibit an incubation period that can extend from 10 to 46 dpa, above which the cluster composition changes and a separate phase, (G-phase) forms. Both neutron and heavy ion irradiation showed that these clusters develop slowly and continue to evolve beyond 100 dpa. Overall, this work shows that the irradiated microstructure features produced by heavy ion irradiation are remarkably comparable in nature to those produced by neutron irradiation at much lower dose rates. The use of a temperature shift to account for the higher damage rate in heavy ion irradiation results in a fairly good match in the dislocation loop microstructure and the precipitate microstructure in austenitic stainless steels. Both irradiations also show segregation of the same elements and in the same directions, but to achieve comparable magnitudes, heavy ion irradiation must be conducted at a much higher temperature than that which produces a match with loops and precipitates. First-principles modeling has confirmed that the formation of Ni-Si precipitates under irradiation is likely caused by supersaturation of solute to defect sinks caused by highly correlated diffusion of Ni and Si. Thus, the formation and evolution of Ni-Si precipitates at high dose in austenitic stainless steels containing Si is inevitable.

  2. Stick-slip water penetration into capillaries coated with swelling hydrogel.

    Science.gov (United States)

    Silva, J E; Geryak, R; Loney, D A; Kottke, P A; Naik, R R; Tsukruk, V V; Fedorov, A G

    2015-08-07

    We have observed intriguing stick-slip behavior during capillary pressure driven filling of borosilicate microtubes coated with hydrogel on their inner wall. Swelling of hydrogel upon exposure to a translating waterfront is accompanied by "stick-and-slip" motion. This results in the macroscopic filling velocity for water penetration into glass capillaries coated with poly(N-isopropylacrylamide) (PNIPAM) being constant throughout the filling process, and reduced by three orders of magnitude when compared to filling of uncoated capillaries. A simple scaling analysis is used to introduce a possible explanation by considering the mechanisms responsible for pinning and unpinning of the contact line. The explanation assumes that the time scale for water diffusion into a hydrogel film and the resulting swelling/change of the local meniscus contact angle define the duration of each "stick" event. The "slip" length scale is in turn established by the elastocapillary deformation of dry hydrogel at the pinning point of the contact line. The sequential dynamics of these processes then determine the rate of water filling into a swelling capillary. Collectively, these experimental and theoretical results provide a new conceptual framework for liquid motion confined by soft, dynamically evolving polymer interfaces, in which the system creates an energy barrier to further motion through elasto-capillary deformation, and then lowers the barrier through diffusive softening. This insight has implications for optimal design of microfluidic and lab-on-a-chip devices based on stimuli-responsive smart polymers.

  3. Sustainable and smart keratin hydrogel with pH-sensitive swelling and enhanced mechanical properties.

    Science.gov (United States)

    Peralta Ramos, María Luz; González, Joaquín Antonio; Fabian, Lucas; Pérez, Claudio Javier; Villanueva, María Emilia; Copello, Guillermo Javier

    2017-09-01

    Protein based hydrogels are a very interesting type of biomaterials with many probed strengths related to their source and chemical structure. Biocompatibility and biodegradability are accompanied by affordability when it comes to low cost sources. The main keratin source is agroindustrial waste, such as feathers, horns, hooves, hair and wool. Thus, the main cost of keratin hydrogels derives from their processing. Here is presented a new strategy for the obtaining of a keratin hydrogel with enhanced mechanical properties using low cost reagents. This keratin hydrogel is stiff enough to allow handling without special cares and also presenting a reversible pH-responsive behavior. The minimum swelling is observed at low pH due to a collapsed and disordered protein network with water tightly adsorbed to the hydrophilic sites. The swelling rises significantly above pH6 and the maximum swelling appears above pH8 where an expanded network allows water to enter to the pores. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. MAPPING REMOVAL SWELLING CLAY SOILS IN THE AURES (N’GAOUS ALGERIA

    Directory of Open Access Journals (Sweden)

    Rahmani MOUNA

    2016-09-01

    Full Text Available The shrinkage and swelling phenomena of certain clay soils cause differential settlement manifested by disorders that affect mainly the individual frame. The objective of this research was to create a map related to these phenomena especially in the area of Algeria N’gaous (figure 1. The approach of the study is primarily based firstly on the interpretation of a geological map at a scale 1 : 50 000 and on the other part from existing literature and observations on a synthesis of a large number of geotechnical information to determine susceptibility to the phenomenon of clay or marl formations. This approach consisted in the establishment of a synthetic departmental mapping of these formations that have been identified from a hierarchy as to their susceptibility according to the shrinkage and swelling phenomenon. This classification was established on the basis of three quantifiable main features: the dominant lithology of formations, the mineralogical composition of their clay fraction (proportion of swelling minerals and geotechnical behavior (primarily assessed from the blue value and the plasticity index.

  5. Gigantic swelling of inorganic layered materials: a bridge to molecularly thin two-dimensional nanosheets.

    Science.gov (United States)

    Geng, Fengxia; Ma, Renzhi; Ebina, Yasuo; Yamauchi, Yusuke; Miyamoto, Nobuyoshi; Sasaki, Takayoshi

    2014-04-09

    Platy microcrystals of a typical layered material, protonated titanate, have been shown to undergo an enormous degree of swelling in aqueous solutions of various amines, including tertiary amines, quaternary ammonium hydroxides, and primary amines. Introducing these solutions expanded the crystal gallery height by up to ~100-fold. Through systematic analysis, we determined that ammonium ion intercalation is predominantly affected by the acid-base equilibrium and that the degree of swelling or inflow of H2O is controlled by the osmotic pressure balance between the gallery and the solution environment, both of which are relatively independent of electrolyte identity but substantially dependent on molarity. In solutions of tertiary amines and quaternary ammonium hydroxides, the uptake of ammonium ions increases nearly linearly with increasing external concentration before reaching a saturation plateau, i.e., ~40% relative to the cation-exchange capacity of the crystals used. The only exception is tetrabutylammonium ions, which yield a lower saturation value, ~30%, owing to steric effects. The swelling behaviors in some primary amine solutions differ as a result of the effect of attractive forces between amine solute molecules on the solution osmotic pressure. Although the swelling is essentially colligative in nature, the stability of the resultant swollen structure is heavily dependent on the chemical nature of the guest ions. Intercalated ions of higher polarity and smaller size help stabilize the swollen structure, whereas ions of lower polarity and larger size lead readily to exfoliation. The insight gained from this study sheds new light on both the incorporation of guest molecules into a gallery of layered structures in general and the exfoliation of materials into elementary single-layer nanosheets.

  6. A brief review of cavity swelling and hardening in irradiated copper and copper alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J.

    1990-01-01

    The literature on radiation-induced swelling and hardening in copper and its alloy is reviewed. Void formation does not occur during irradiation of copper unless suitable impurity atoms such as oxygen or helium are present. Void formation occurs for neutron irradiation temperatures of 180 to 550{degree}C, with peak swelling occurring at {approximately}320{degree}C for irradiation at a damage rate of 2 {times} 10{sup {minus}7} dpa/s. The post-transient swelling rate has been measured to be {approximately}0.5%/dpa at temperatures near 400{degree}C. Dispersion-strengthened copper has been found to be very resistant to void swelling due to the high sink density associated with the dispersion-stabilized dislocation structure. Irradiation of copper at temperatures below 400{degree}C generally causes an increase in strength due to the formation of defect clusters which inhibit dislocation motion. The radiation hardening can be adequately described by Seeger's dispersed barrier model, with a barrier strength for small defect clusters of {alpha} {approx} 0.2. The radiation hardening apparently saturates for fluences greater than {approximately}10{sup 24} n/m{sup 2} during irradiation at room temperature due to a saturation of the defect cluster density. Grain boundaries can modify the hardening behavior by blocking the transmission of dislocation slip bands, leading to a radiation- modified Hall-Petch relation between yield strength and grain size. Radiation-enhanced recrystallization can lead to softening of cold-worked copper alloys at temperatures above 300{degree}C.

  7. Characterizing the Swelling of a Crosslinked Organosilicon Polymer

    Science.gov (United States)

    Thornburg, Zane; Bonvallet, Paul

    A hydrophobic crosslinked organosilicon polymer, known by the trade name Osorb, absorbs many times its own weight in liquid- and vapor-phase organic solvents. Its Si-O-Si linkage is likely flexible, analogously to physical and spectroscopic measurements in various forms of silica. Infrared spectroscopy is commonly used due to the sensitivity of certain vibrational modes to changes in geometry and environment. We hypothesized that the Si-O-Si bond angle within the Osorb matrix changes when the material swells upon exposure to organic solvents. Density functional theory calculations on a small-molecule model system qualitatively agree with the central force model of glassy solids, which relates the IR vibrational frequency of the system to the angle and force constant of this bond. Treatment of various Osorb samples with decane consistently causes a moderate increase in the frequency of the asymmetric stretching band around 1100 cm-1. However, the spectroscopic changes do not correlate with the swell capacity of the material. In fact, some low-swelling samples showed the same changes in frequency as high-swelling samples, thus demonstrating that the swelling of Osorb is not due to changes in the Si-O-Si bond angle. National Science Foundation DMR-1560093.

  8. STUDY OF A SOIL WITH SWELLING AND SHRINKING PHENOMENA

    Directory of Open Access Journals (Sweden)

    G. Rogobete

    2012-12-01

    Full Text Available Vertisols are deep clayey soils, with more than 45 % clay, dominated by clay minerals, such as smectites, that expand upon wetting and shrink upon drying. The most important physical characteristics of Vertisols are a low hydraulic conductivity and stickiness when wet and high flow of water through the cracks when dry. They become very hard when dry and in all the time are difficult to work. During the rainy season, the cracks disappear and the soil becomes sticky and plastic with a very slippery surface which makes Vertisols in – trafficable when wet. Water movement in soil that change volume with water content is not well understood and management of swelling soil remains problematic. Swelling or shrinking result in vertical displacement of the wet soil, which involves gravitational work and contributes to an overburden component to the total potential of the soil water. Many swelling soil crack and the network of cracks provides pathways for rapid flow of water which prejudice application of theory based on Darcian flow. One – dimensional flow of water in a swelling system requires material balance equation for both the aqueous and solid phases. The analytical data offers some values particle – size distribution, compression, swelling degree and pressure, plasticity index, elastic modulus, triaxial shear, angle of shear and load carrying capacity in order to realize a foundation study for some constructions.

  9. Adsorption-induced deformation of microporous materials: coal swelling induced by CO2-CH4 competitive adsorption.

    Science.gov (United States)

    Brochard, Laurent; Vandamme, Matthieu; Pellenq, Roland J-M; Fen-Chong, Teddy

    2012-02-07

    Carbon dioxide injection in coal seams is known to improve the methane production of the coal seam, while ensuring a safe and long-term carbon sequestration. This improvement is due to the preferential adsorption of CO(2) in coal with respect to CH(4): an injection of CO(2) thus results in a desorption of CH(4). However, this preferential adsorption is also known to cause a differential swelling of coal, which results in a significant decrease in the reservoir permeability during the injection process. Recent studies have shown that adsorption in coal micropores (few angströms in size) is the main cause of the swelling. In this work, we focus on the competitive adsorption behavior of CO(2) and CH(4) in micropores. We perform molecular simulations of adsorption with a realistic atomistic model for coal. The competitive adsorption is studied at various temperatures and pressures representative of those in geological reservoirs. With the help of a poromechanical model, we then quantify the subsequent differential swelling induced by the computed adsorption behaviors. The differential swelling is almost insensitive to the geological temperatures and pressures considered here and is proportional to the CO(2) mole fraction in the coal.

  10. Irradiation creep and void swelling of two LMR heat of HT9 at {approx}400{degrees}C and 165 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Toloczko, M.B. [Univ. of California, Santa Barbara, CA (United States); Garner, F.A. [Pacific Northwest National Laboratory, Richland, WA (United States)

    1996-04-01

    Two nominally identical heats of HT9 ferritic-martensitic steel were produced, fabricated into pressurized tubes, and then irradiated in FFTF, using identical procedures. After reaching 165 dpa at {approx}400C, small differences in strains associated with both phase-related change in lattice parameter and void swelling were observed in comparing the two heats. The creep strains, while different, exhibited the same functional relationship to the swelling behavior. The derived creep coefficients, the one associated with creep in the absence of swelling and the one directly responsive to swelling, were essentially identical for the two heats. Even more significantly, the creep coefficients for this bcc ferritic-martensitic steel appear to be very similar and possibly identical to those routinely derived from creep experiments on fcc austenitic steels.

  11. Swelling studies of camel and bovine corneal stroma

    Directory of Open Access Journals (Sweden)

    Turki Almubrad

    2010-09-01

    Full Text Available Turki Almubrad, Mohammad Faisal Jamal Khan, Saeed AkhtarCornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, Saudi ArabiaAbstract: In the present study we investigated the swelling characteristics of fresh camel and bovine cornea in sodium salt solutions. Swelling studies were carried out at 20 minutes, 14 hours, and 46 hours on five fresh camel and 5 five fresh bovine corneas. During the 20-minute hydration of fresh corneal stroma was investigated using sodium chloride (NaCl, sodium bicarbonate (NaHCO3, sodium acetate (CH3COONa, sodium thiocyanate (NaSCN, and sodium floride (NaF at 2-minute time intervals. During a 46-hour time period, the hydration study was carried out using NaCl (150, 300 mM and NaF (150 mM at random intervals. The 14-hour study was carried out to assess the rehydration of corneal stroma after 6 hours of drying. During the 20-minute swelling studies in the first 2 minutes the rate of hydration in both camel and bovine corneas was high but gradually reduced in the 2–20-minute period. The rates and levels of hydration of camel and bovine cornea were not significantly different from each other in all the strengths of solutions. During the 46-hour swelling studies, the initial rate of hydration (0–2 hours of camel and bovine stroma, in all solutions was significantly higher (Z = 0.056 compared to hydration during later hours (2–46 hours. Camel stromal hydration (high in 150 mM NaCl was significantly higher compared to bovine stromal hydration in the same solution during the 10–24, and 24–46-hour time periods. Rehydration in camel stroma was significantly lower than bovine in 150 mM NaF. The 20-minute study showed that there was no selective affinity for particular ions in camel or bovine corneal stroma. Initial swelling in both corneal and bovine stroma is faster and more prominant compared to later swelling. The swelling in camel cornea is more prominant compared

  12. Temporomandibular joint osteochondromatosis: an unusual cause of preauricular swelling.

    LENUS (Irish Health Repository)

    Phelan, Eimear

    2012-02-01

    We report an unusual and rare cause of preauricular swelling and review the most recent literature concerning synovial osteochondromatosis of the temporomandibular joint. We report the clinical and radiologic findings of a case of synovial osteochondromatosis of the temporomandibular joint that presented as preauricular swelling in a female patient. This disease typically affects large joints; fewer than 100 cases reported in the literature affect the temporomandibular joint. This case illustrates that disorders of the temporomandibular joint should also be included in the differential diagnosis of patients who present with a preauricular mass.

  13. Mitigation of Voltage Swells by Static Series Compensator

    DEFF Research Database (Denmark)

    Awad, Hilmy; Blaabjerg, Frede

    2004-01-01

    Swells and overvoltages can cause overheating, tripping or even destruction of industrial equipment such as motor drives and control relays. This paper investigates the possibility of employing the Static Series Compensator (SSC) to mitigate voltage swells/overvoltages. In the case of voltage...... is lower than a predetermined voltage level, the active power is employed to charge the ESC to this voltage level; 2) otherwise, the overvoltage protection of the SSC must operate. This paper also applies an overvoltage protection scheme based on a combination of a dc resistor with a chopper and the valves...

  14. The physicochemical properties of polyurethane membranes determined by swelling measurements

    Science.gov (United States)

    Ciobanu, Gabriela; Carja, Gabriela; Apostolescu, Gabriela; Apostolescu, Nicolae

    2009-01-01

    In this work, we have dispersed SAPO-5 zeolite particles in polyurethane matrix for preparation of porous mixed matrix membranes. The goal of work is the determination of the cohesive energy density for unfilled- and zeolite - filled polyurethane membranes. Experimental determination of cohesive energy density values for the prepared membranes is obtained by measuring the swelling coefficients in water and several alcohols (methanol, ethanol, propanol and butanol). The solubility parameters of the membranes are also calculated. For the unfilled membranes the corresponded values of cohesive energy density and solubility parameter increase in comparison to those of the filled membranes. All the tested membranes show a tendency to swell with ethanol.

  15. Influence of effective stress on swelling pressure of expansive soils

    Directory of Open Access Journals (Sweden)

    Baille Wiebke

    2016-01-01

    Full Text Available The volume change and shear strength behaviour of soils are controlled by the effective stress. Recent advances in unsaturated soil mechanics have shown that the effective stress as applicable to unsaturated soils is equal to the difference between the externally applied stress and the suction stress. The latter can be established based on the soil-water characteristic curve (SWCC of the soil. In the present study, the evolution of swelling pressure in compacted bentonite-sand mixtures was investigated. Comparisons were made between magnitudes of applied suction, suction stress, and swelling pressure.

  16. Swelling, ion uptake and biodegradation studies of PE film modified through radiation induced graft copolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Inderjeet, E-mail: ij_kaur@hotmail.com [Department Chemistry, HPU Shimla 171005 (India); Gupta, Nitika; Kumari, Vandna [Department Chemistry, HPU Shimla 171005 (India)

    2011-09-15

    An attempt to develop biodegradable polyethylene film grafting of mixture of hydrophilic monomers methacrylic acid (MAAc) and acrylamide (AAm) onto PE film has been carried out by preirradiation method using benzoyl peroxide as the radical initiator. Since ether linkages are susceptible to easy cleavage during degradation process, PE film was irradiated before the grafting reactions by {gamma}-rays to introduce peroxidic linkages (PE-OO-PE) that offer sites for grafting. The effect of irradiation dose, monomer concentration, initiator concentration, temperature, time and amount of water on the grafting percent was determined. Maximum percentage of grafting of binary mixture (MAAc+AAm), (1792%) was obtained at a total concentration of binary monomer mixture=204.6x10{sup -2} mol/L ([MAAc]=176.5x10{sup -2} mol/L, [AAm]=28.1x10{sup -2} mol/L), [BPO]=8.3x10{sup -2} mol/L at 100 deg. C in 70 min. The grafted PE film was characterized by the Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopic (SEM) methods. Some selective properties of grafted films such as swelling studies, ion uptake and biodegradation studies have been investigated. The grafted films show good swelling in water, ion uptake studies shows promising results for desalination of brackish water and the soil burial test shows that PE film grafted with binary monomer mixture degrades up to 47% within 50 days. - Highlights: > Binary mixture of methacrylic acid (MAAc) and acrylamide (AAm) onto PE film by preirradiation method was carried out. > Graft copolymers of MAAc+AAm and PE film were characterized by FTIR, TGA and SEM studies and was found to be thermally stable. > Grafting of MAAc+AAm improved swelling behavior giving maximum swelling (485.71%) in water as against PE with 0% swelling. > The grafted PE-g-poly (MAAc-co-AAm) behaves as an excellent material for ion separation. > Biodegradation studies by soil burial test showed 47.19% of

  17. Controlled swelling and degradation studies of alginate microbeads in dilute natrium-citrate solutions

    Directory of Open Access Journals (Sweden)

    Mitrović Dragana D.

    2010-01-01

    Full Text Available Alginate hydrogels are widely used in biomedicine due to alginate availability, hydrophilic nature, biocompatibility and biodegradability. Alginate microbeads are particularly attractive for applications in pharmacy and regenerative medicine due to high surface to volume ratio, low mass transfer limitations and simple implantation by injection. Aim of this work was to investigate possibilities for controlled degradation of alginate microbeads in cell culture medium (Dulbecco’s modified Eagle’s medium with Na-citrate added in small concentrations (0.05 - 0.5 mM. Alginate microbeads (1.5% w/w, 800 m in diameter were produced by electrostatic droplet extrusion and evaluated over a period of 10 days regarding appearance, kinetics and degree of swelling as well as biomechanical properties determined in a novel bioreactor with mechanical stimulation under in vivo-like conditions in articular cartilage (10% strain, 337.5 m/s compression rate. In the citrate concentration range investigated, microbeads initially swelled reaching an equilibrium value (~150-170% with respect to the initial mass, upon which they appeared stable for a certain period of time (1 to over 7 days followed by bead bursting and degradation. This degradation process indicated that Na+ ions from the solution initially replaced Ca2+ ions bound mainly to COO- groups in polymannuronate sequences inducing electrostatic repulsion of polymer chains and, consequently, swelling of the beads. Citrate ions assisted in this process by forming insoluble calcium citrate. Thus, the specific rate of the bead swelling increased with the increase in citrate concentration approaching a maximal value of ~0.34 d-1. In the last phase, the beads burst into pieces, which slowly continued to degrade by replacement of Ca2+ ions bonded to polyguluronate blocks in the egg-box structure. Compression moduli for packed beds of control, freshly produced microbeads, and microbeads swelled at the equilibrium

  18. Multiple renal anomalies associated with encapsulated swellings of ...

    African Journals Online (AJOL)

    The current observation reports the occurrence of the left renal anomalies and encapsulated swellings involving the left sciatic nerve in a 47 years old male cadaver. Renal anomalies consisted of left double kidney, left bifid ureter and double arterial supply to the left kidney. The double kidney consisted of the two upper and ...

  19. Thermal effects on granules and direct determination of swelling ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-04

    Aug 4, 2009 ... Doublier JL, Llamas G, Lemeur M (1987). Swelling characteristics of native and chemically modified wheat starches as a function of heating temperature an time. Starch, 56: 181-189. Duprat F, Gallant D, Guilbot A, Mercier C, Robin JP (1980). Les polymères des végétaux. Ed. b. Monties, Gauthier-villars, pp.

  20. A swelling hydrogel-based Pco2 sensor

    NARCIS (Netherlands)

    Herber, S.; Olthuis, Wouter; Bergveld, Piet

    2003-01-01

    This paper reports the exploration of hydrogel as sensor material for the detection of carbon dioxide (CO2). Hydrogel microspheres, which swell or shrink in response to a change in pH, were specifically prepared for this purpose and placed on a pressure sensor membrane. Subsequently, a porous metal

  1. DNA-responsive hydrogels that can shrink or swell.

    Science.gov (United States)

    Murakami, Yoshihiko; Maeda, Mizuo

    2005-01-01

    Molecule-responsive hydrogels are reputed to be smart materials because of their unique properties. We recently reported that hydrogels containing directly grafted single-stranded (ss) DNA or ssDNA-polyacrylamide conjugate in a semi-interpenetrating network (semi-IPN) manner that "only shrunk" by the addition of ssDNA samples. To date, however, no DNA-responsive hydrogels have been reported capable of "swelling" in response to specific DNAs. Smart materials capable of both shrinking and swelling in response to specific DNAs would be very useful in biochemical and biomedical applications. Here, we show a novel "shrinking or swelling" DNA-responsive mechanism. Novel hybrid hydrogels containing rationally designed ssDNA as the cross-linker were capable of shrinking or swelling in response to ssDNA samples and recognizing a single base difference in the samples. On the basis of the results presented in this paper, it is envisioned that these novel hybrid hydrogels could function and have potential in applications such as DNA-sensing devices and DNA-triggered actuators.

  2. Laboratory tests of hydraulic fracturing and swell healing

    DEFF Research Database (Denmark)

    Thunbo, Christensen Claes; Foged, Christensen Helle; Foged, Niels

    1998-01-01

    New laboratory test set-ups and test procedures are described - for testing the formation of hydraulically induced fractures as well as the potential for subsequent fracture closurefrom the relase of a swelling potential. The main purpose with the tests is to provide information on fracturing...... stresses and whether or not the material in question possesses the potential for fracture closure....

  3. Tumescent steroid infiltration to reduce postoperative swelling after craniofacial surgery.

    Science.gov (United States)

    Neil-Dwyer, J G; Evans, R D; Jones, B M; Hayward, R D

    2001-10-01

    Steroids are often administered to paediatric craniomaxillofacial patients perioperatively to reduce postoperative facial swelling, although there is little evidence of their efficacy. Preoperative tumescent infiltration using 7 ml x kg(-1) of a solution consisting of 0.1 mg x ml(-1) triamcinolone acetate, 0.0125% bupivacaine, 0.025% lignocaine, 3 units x ml(-1) hyaluronidase and 1:1000000 adrenaline in Hartmann's solution was evaluated from a retrospective case controlled study of patients undergoing standard fronto-orbital remodelling for simple craniosynostosis (n = 20). Eye closure (i.e. inability to open the eyes) was used as a marker for severe facial swelling. Patients receiving the tumescent infiltration demonstrated significantly less eye closure (P < 0.005), implying that the tumescent infiltration had a significant effect on facial swelling. The avoidance of eye closure allowed more effective monitoring for neurological and ophthalmological complications, which is a significant clinical benefit. The infiltration solution has the advantage of a lower corticosteroid dose than previously reported dexamethasone-based perioperative regimens, thereby minimising any unwanted metabolic effects. The technique is advocated for the reduction of postoperative facial swelling in craniomaxillofacial surgical patients. Copyright 2001 The British Association of Plastic Surgeons.

  4. Clozapine- induced recurrent and transient parotid gland swelling

    African Journals Online (AJOL)

    agonist activity at the M4 muscarinic receptor and modest antagonistic effect on D2-like receptors.1 Clozapine is known to be superior to other antipsychotics and is effective in 30-50% of patients .... Brodkin ES, Pelton GH, Price LH. Treatment of clozapine-induced parotid gland swelling. Am J Psychiatry 1996; 153(3): 445.

  5. Grewia Gum 1: Some Mechanical and Swelling Properties of ...

    African Journals Online (AJOL)

    Methods: Compacts (500 mg) of both freeze-dried and air-dried grewia gum were separately prepared by compression on a potassium bromide (KBr) press at different pressures and subjected to Heckel analysis. Swelling studies were performed using 200 mg compacts of the gum (freeze-dried or air-dried) compressed on ...

  6. Cell swelling and glycogen metabolism in hepatocytes from fasted rats

    NARCIS (Netherlands)

    Gustafson, L. A.; Jumelle-Laclau, M. N.; van Woerkom, G. M.; van Kuilenburg, A. B.; Meijer, A. J.

    1997-01-01

    Cell swelling is known to increase net glycogen production from glucose in hepatocytes from fasted rats by activating glycogen synthase. Since both active glycogen synthase and phosphorylase are present in hepatocytes, suppression of flux through phosphorylase may also contribute to the net increase

  7. Kimura's disease: A case presentation of postauricular swelling ...

    African Journals Online (AJOL)

    Kimura's disease: A case presentation of postauricular swelling. A Rajesh, T Prasanth, V.C. Naga Sirisha, M.D.S. Azmi. Abstract. Kimura's disease (KD) is a rare chronic inflammatory disease of subcutaneous tissues and occurs predominantly in head and neck region. It is seen primarily in young Asian males. Typical clinical ...

  8. Clozapine- induced recurrent and transient parotid gland swelling

    African Journals Online (AJOL)

    Robinson D, Fenn H, Yesavage J. Possible association of parotitis with clozapine (letter). Am J Psychiatry 1995; 152: 297-298. 6. Brodkin ES, Pelton GH, Price LH. Treatment of clozapine-induced parotid gland swelling. Am J Psychiatry 1996; 153(3): 445. 7. Naranjo CA, Busto U, Sellers EM, et al. A method for estimating the.

  9. How does a flexible chain of active particles swell?

    Science.gov (United States)

    Kaiser, Andreas; Babel, Sonja; ten Hagen, Borge; von Ferber, Christian; Löwen, Hartmut

    2015-03-28

    We study the swelling of a flexible linear chain composed of active particles by analytical theory and computer simulation. Three different situations are considered: a free chain, a chain confined to an external harmonic trap, and a chain dragged at one end. First, we consider an ideal chain with harmonic springs and no excluded volume between the monomers. The Rouse model of polymers is generalized to the case of self-propelled monomers and solved analytically. The swelling, as characterized by the spatial extension of the chain, scales with the monomer number defining a Flory exponent ν which is ν = 1/2, 0, 1 in the three different situations. As a result, we find that activity does not change the Flory exponent but affects the prefactor of the scaling law. This can be quantitatively understood by mapping the system onto an equilibrium chain with a higher effective temperature such that the chain swells under an increase of the self-propulsion strength. We then use computer simulations to study the effect of self-avoidance on active polymer swelling. In the three different situations, the Flory exponent is now ν = 3/4, 1/4, 1 and again unchanged under self-propulsion. However, the chain extension behaves non-monotonic in the self-propulsion strength.

  10. Effects of Heterogeneous Sink Distribution on Void Swelling

    DEFF Research Database (Denmark)

    Leffers, Torben; Volobuyev, A. V.; Gann, V. V.

    1986-01-01

    Swelling rates are calculated for two types of material with heterogeneous distributions of dislocations and voids, namely copper irradiated with neutrons to low dose at 250 degree C and heavily cold-worked copper irradiated with 1 MeV electrons in a HVEM at 250 degree C. Both materials are consi......Swelling rates are calculated for two types of material with heterogeneous distributions of dislocations and voids, namely copper irradiated with neutrons to low dose at 250 degree C and heavily cold-worked copper irradiated with 1 MeV electrons in a HVEM at 250 degree C. Both materials...... are considered to consist of non-interacting spherical components with a wall and an inner cell with different dislocation and/or void densities. We subdivide the sphere (wall plus cell) in a number of concentric shells and find a quasi-static solution for the interstitial and vacancy concentrations...... in the different shells by a finite-difference method. From these concentrations the local and the average swelling rate and the dependence of this effect of the heterogeneities in sink distribution on swelling rate and the dependence of this effect on various structural parameters are investigated....

  11. Evaluation Of Postoperative Facial Swelling Following The Surgical ...

    African Journals Online (AJOL)

    Patients and Methods: Clinical evaluation of facial swelling after the surgical removal of impacted mandibular third molars using a tape measuring technique was ... The tape measuring method is simple, non-invasive, cost effective and time-saving method, which provides numerical data for determination of facial contour ...

  12. Evaluating the swelling, erosion, and compaction properties of cellulose ethers.

    Science.gov (United States)

    Ghori, Muhammad U; Grover, Liam M; Asare-Addo, Kofi; Smith, Alan M; Conway, Barbara R

    2018-02-01

    Swelling, erosion, deformation, and consolidation properties can affect the performance of cellulose ethers, the most commonly used matrix former in hydrophilic sustained tablet formulations. The present study was designed to comparatively evaluate the swelling, erosion, compression, compaction, and relaxation properties of the cellulose ethers in a comprehensive study using standardised conditions. The interrelationship between various compressional models and the inherent deformation and consolidation properties of the polymers on the derived swelling and erosion parameters are consolidated. The impact of swelling (K w ) on erosion rates (K E ) and the inter-relationship between Heckel and Kawakita plasticity constants was also investigated. It is evident from the findings that the increases in both substitution and polymer chain length led to higher K w , but a lower K E ; this was also true for all particle size fractions regardless of polymer grade. Smaller particle size and high substitution levels tend to increase the relative density of the matrix but reduce porosity, yield pressure (P y ), Kawakita plasticity parameter (b -1 ) and elastic relaxation. Both K W versus K E (R 2  = 0.949-0.980) and P y versus. b -1 correlations (R 2  = 0.820-0.934) were reasonably linear with regards to increasing hydroxypropyl substitution and molecular size. Hence, it can be concluded that the combined knowledge of swelling and erosion kinetics in tandem with the in- and out-of-die compression findings can be used to select a specific polymer grade and further to develop and optimize formulations for oral controlled drug delivery applications.

  13. Modeling Hydraulic Properties and Hydrologic Processes in Shrink-swell Clay Soils

    Science.gov (United States)

    Stewart, R. D.; Rupp, D. E.; Abou Najm, M. R.; Selker, J. S.

    2015-12-01

    Recognizing the need for tractable models that accurately describe the hydrologic behaviors of shrink-swell soils, we propose a new conceptual model that identifies up to five porosity domains based on morphological and hydrological distinctions. We provide governing equations that predict the porosity distribution as a function of soil water content and six additional parameters, all of which can be determined using laboratory measurements conducted on individual soil samples. We next derive new expressions for the hydraulic properties of such soils, which can be used to model infiltration at the plot scale. Finally, we incorporate these expressions into new models that can be used to predict and quantify surface runoff (i.e., overland flow) thresholds, and which may be used to reveal the dominant mechanisms by which water moves through clayey soils. Altogether, these models successfully link small-scale shrinkage/swelling behaviors with large-scale processes, and can be applied to such practical applications as converting measurements between gravimetric and volumetric water contents, as well as to predicting field-scale processes such as the sealing of individual cracks.

  14. Massive hydration-driven swelling of layered perovskite niobate crystals in aqueous solutions of organo-ammonium bases.

    Science.gov (United States)

    Song, Yeji; Iyi, Nobuo; Hoshide, Tatsumasa; Ozawa, Tadashi C; Ebina, Yasuo; Ma, Renzhi; Yamamoto, Shinya; Miyamoto, Nobuyoshi; Sasaki, Takayoshi

    2017-11-08

    Osmotic swelling behaviors in layered perovskite niobate were examined in aqueous solutions containing three types of amine-related agents including quaternary ammonium hydroxides and tertiary aminoethanol. Platelet microcrystals of a protonated layered perovskite niobate, HCa2Nb3O10·1.5H2O, were found to show enormous swelling in the aqueous solutions, which was clearly recognized by the noticeable expansion of the sample volume over 100-fold. Optical microscopy observations revealed that the crystals underwent accordion-like elongation in the layer-stacking direction up to several ten-fold the initial thickness. Small-angle X-ray scattering measurements of swollen samples indicate the expansion of interlayer separation ranging from ∼20 nm to over 100 nm, which is primarily governed by the concentrations of the amine-related agents. The magnitudes of the interlayer separation were comparable to those of the macroscopic swelling. The degree of swelling was progressively suppressed with further increasing concentration, and this suppression trend was related to the amines.

  15. Long-term water absorption and thickness swelling and determine their characteristics in wood flour/polypropylene/Nano SiO2 nanocomposite

    Directory of Open Access Journals (Sweden)

    Saeed Ismaeilimoghadam

    2016-09-01

    Full Text Available The objective of this study was to investigate the effect of nano SiO2 on long-term water absorption and thickness swelling, humidity coefficient diffusion and thickness swelling rate of wood plastic composite. For this purpose, 60% wood flour, 40% polypropylene, 2 per hundred compound (phc MAPP in internal mixer (HAAKE were mixed. Nano SiO2 with 0, 1, 3 and 5 (phc ratios as a reinforcing was used too. Finally test samples were fabricated by using the injection molding machine. Then long-term water absorption and thickness swelling for 1848 hours according to the ASTM standard on the samples were measured. Humidity coefficient diffusion and thickness swelling rate for closer look long-term water absorption and thickness swelling behavior in wood plastic nanocomposite were calculated too. For ensure to the formation of hydrogen bonds between hydroxyl grope of SiO2 nanoparticles with hydroxyl grope of wood flour form Fourier transform infrared (FTIR spectroscopy tests was used. The results showed that water absorption behavior of nanocomposite is according to Fick's law, in addition with increasing to SiO2 nanoparticles, long-term water absorption and thickness swelling and humidity coefficient diffusion in wood plastic nanocomposite decreased. The results of infrared spectroscopy showed that hydrogen bond between the nano SiO2 and wood flour confirmed. Statistical analysis showed that after 1848 hours of immersion, nano SiO2 showed a significant effect at a confidence level of 99% on water absorption and thickness swelling, so the sample with 5% silica nanoparticles was chosen as the best treatment.

  16. Behaviorism

    National Research Council Canada - National Science Library

    Moore, J

    2011-01-01

    .... Watson proposed an alternative: classical S-R behaviorism. According to Watson, behavior was a subject matter in its own right, to be studied by the observational methods common to all sciences...

  17. Swelling/floating capability and drug release characterizations of gastroretentive drug delivery system based on a combination of hydroxyethyl cellulose and sodium carboxymethyl cellulose.

    Directory of Open Access Journals (Sweden)

    Ying-Chen Chen

    Full Text Available The aim of this study was to characterize the swelling and floating behaviors of gastroretentive drug delivery system (GRDDS composed of hydroxyethyl cellulose (HEC and sodium carboxymethyl cellulose (NaCMC and to optimize HEC/NaCMC GRDDS to incorporate three model drugs with different solubilities (metformin, ciprofloxacin, and esomeprazole. Various ratios of NaCMC to HEC were formulated, and their swelling and floating behaviors were characterized. Influences of media containing various NaCl concentrations on the swelling and floating behaviors and drug solubility were also characterized. Finally, release profiles of the three model drugs from GRDDS formulation (F1-4 and formulation (F1-1 were examined. Results demonstrated when the GRDDS tablets were tested in simulated gastric solution, the degree of swelling at 6 h was decreased for each formulation that contained NaCMC in comparison to those in de-ionized water (DIW. Of note, floating duration was enhanced when in simulated gastric solution compared to DIW. Further, the hydration of tablets was found to be retarded as the NaCl concentration in the medium increased resulting in smaller gel layers and swelling sizes. Dissolution profiles of the three model drugs in media containing various concentrations of NaCl showed that the addition of NaCl to the media affected the solubility of the drugs, and also their gelling behaviors, resulting in different mechanisms for controlling a drug's release. The release mechanism of the freely water-soluble drug, metformin, was mainly diffusion-controlled, while those of the water-soluble drug, ciprofloxacin, and the slightly water-soluble drug, esomeprazole, were mainly anomalous diffusion. Overall results showed that the developed GRDDS composed of HEC 250HHX and NaCMC of 450 cps possessed proper swelling extents and desired floating periods with sustained-release characteristics.

  18. COAL CLEANING VIA LIQUID-FLUIDIZED CLASSIFICAITON (LFBC) WITH SELECTIVE SOLVENT SWELLING

    Energy Technology Data Exchange (ETDEWEB)

    J. M. Calo

    2000-12-01

    The concept of coal beneficiation due to particle segregation in water-fluidized beds, and its improvement via selective solvent-swelling of organic material-rich coal particles, was investigated in this study. Particle size distributions and their behavior were determined using image analysis techniques, and beneficiation effects were explored via measurements of the ash content of segregated particle samples collected from different height locations in a 5 cm diameter liquid-fluidized bed column (LFBC). Both acetone and phenol were found to be effective swelling agents for both Kentucky No.9 and Illinois No.6 coals, considerably increasing mean particle diameters, and shifting particle size distributions to larger sizes. Acetone was a somewhat more effective swelling solvent than phenol. The use of phenol was investigated, however, to demonstrate that low cost, waste solvents can be effective as well. For unswollen coal particles, the trend of increasing particle size from top to bottom in the LFBC was observed in all cases. Since the organic matter in the coal tends to concentrate in the smaller particles, the larger particles are typically denser. Consequently, the LFBC naturally tends to separate coal particles according to mineral matter content, both due to density and size. The data for small (40-100 {micro}m), solvent-swollen particles clearly showed improved beneficiation with respect to segregation in the water-fluidized bed than was achieved with the corresponding unswollen particles. This size range is quite similar to that used in pulverized coal combustion. The original process concept was amply demonstrated in this project. Additional work remains to be done, however, in order to develop this concept into a full-scale process.

  19. Swelling of olecranon bursa in uremic patients receiving hemodialysis.

    Science.gov (United States)

    Handa, S. P.; Khaliq, S. U.

    1978-01-01

    Three patients with chronic renal failure who received therapy with hemodialysis through arteriovenous fistulas in the forearm had fluctuating swelling over the elbow on the same side as the fistula used for the dialysis. The clinical findings in each case were compatible with olecranon bursitis with effusion. The aspirate obtained from the swellings contained lymphocytes, polymorphonuclear leukocytes and histiocytes, a finding similar to that in cases of uremic pericardial and pleural effusion. Biopsy of the bursa in one case showed hyalinized collagenous tissue with infiltration by histiocytes and lymphocytes, reflecting underlying chronic inflammation. Uremia was believed to be the causative factor. Bursitis with effusion is considered to be one of the clinical aspects of uremic polyserositis. Images FIG. 1 FIG. 2 PMID:638913

  20. Swell activated chloride channel function in human neutrophils

    Energy Technology Data Exchange (ETDEWEB)

    Salmon, Michael D. [Leukocyte and Ion Channel Research Laboratory, School of Health and Biosciences, University of East London, Stratford Campus, London E15 4LZ (United Kingdom); Ahluwalia, Jatinder, E-mail: j.ahluwalia@uel.ac.uk [Leukocyte and Ion Channel Research Laboratory, School of Health and Biosciences, University of East London, Stratford Campus, London E15 4LZ (United Kingdom)

    2009-04-17

    Non-excitable cells such as neutrophil granulocytes are the archetypal inflammatory immune cell involved in critical functions of the innate immune system. The electron current generated (I{sub e}) by the neutrophil NADPH oxidase is electrogenic and rapidly depolarises the membrane potential. For continuous function of the NADPH oxidase, I{sub e} has to be balanced to preserve electroneutrality, if not; sufficient depolarisation would prevent electrons from leaving the cell and neutrophil function would be abrogated. Subsequently, the depolarisation generated by the neutrophil NADPH oxidase I{sub e} must be counteracted by ion transport. The finding that depolarisation required counter-ions to compensate electron transport was followed by the observation that chloride channels activated by swell can counteract the NADPH oxidase membrane depolarisation. In this mini review, we discuss the research findings that revealed the essential role of swell activated chloride channels in human neutrophil function.

  1. Magnetic relaxation - coal swelling, extraction, pore size. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Doetschman, D.C.

    1994-10-26

    The aim of the contract was to employ electron and nuclear magnetic relaxation techniques to investigate solvent swelling of coals, solvent extraction of coals and molecular interaction with solvent coal pores. Many of these investigations have appeared in four major publications and a conference proceedings. Another manuscript has been submitted for publication. The set of Argonne Premium Coals was chosen as extensively characterized and representative samples for this project.

  2. High swelling rates observed in neutron-irradiated V-Cr and V-Si binary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Garner, F.A.; Gelles, D.S. [Pacific Northwest Lab., Richland, WA (United States); Takahashi, H.; Ohnuki, S.; Kinoshita, H. [Hokkaido Univ., Sapporo (Japan); Loomis, B.A. [Argonne National Lab., IL (United States)

    1991-11-01

    Additions of 5 to 14 wt% chromium to vanadium lead to very large swelling rates during neutron irradiation of the binary alloys, with swelling increasing strongly at higher irradiation temperatures. Addition of 2 wt% silicon to vanadium also leads to very large swelling rates but swelling decreases with increasing irradiation temperature. Addition of 1 wt% zirconium does not yield high swelling rates, however.

  3. Ultrasonography as a diagnostic tool in orofacial swellings

    Directory of Open Access Journals (Sweden)

    Sunidhi Garg

    2017-01-01

    Full Text Available Introduction: For several years, ultrasonography has played a major role as a diagnostic and therapeutic tool in various medical fields. Only recently has it been used for maxillofacial imaging. Aims and Objectives: To evaluate the reliability of ultrasonography as an alternative tool in the diagnosis of swellings in the orofacial region. Materials and Methods: Ultrasonographic examination of 30 patients of both the sexes aged between 8 and 70 years with swelling in the orofacial region was conducted. Doppler investigation was done in some cases to evaluate the vascularity. The following six sonographic parameters were recorded: shape, boundary echo, internal echo, distribution of internal echoes, posterior wall echoes, and vascularity. Following the clinical and ultrasonographic diagnosis, the lesion was subjected to histopathological examination and a final diagnosis was made. The ultrasonographic diagnosis was correlated with the clinical and histopathological diagnosis. Results: A significant association was observed between both clinical and histopathological diagnosis and ultrasonographic diagnosis (contingency = 0.888, P value = 0.000. Conclusion: Along with clinical and histopathological examinations, ultrasonography works out as a valuable adjunct in the diagnosis of orofacial swellings as it provides several advantages like it is non-invasive, easily reproducible, widely available, rapid, and inexpensive.

  4. Influence of different alcohols on the swelling behaviour of hydrogels

    Science.gov (United States)

    Althans, Daniel; Langenbach, Kai; Enders, Sabine

    2012-06-01

    The swelling equilibrium of cross-linked poly(N-isopropylacrylamide) (PNIPAAm) hydrogels in alcohol solutions as a function of temperature, alcohol concentration, kind of alcohol (C1OH-C3OH) and gel properties was investigated experimentally. Additionally, the swelling degree as a function of the alcohol concentration was modelled with the UNIQUAC-Free Volume model in combination with the Phantom Network theory. The experiments show that, in pure water, the transition temperature is between 303.15 and 308.15 K depending on the properties of the gel and hence on the polymerization conditions. The transition from a swollen to a shrunken state is caused by the polymeric network and the change of polymer chain localization. In a system with hydrogel + water + alcohol, the swelling degree decreases with increasing alcohol concentration until the shrunken state is reached and increases again by further addition of alcohol at constant temperature. With increasing carbon number of the alcohols, the transition from a swollen to a shrunken state and vice versa shifts to lower concentrations at constant temperature. The use of the UNIQUAC-Free Volume model with Phantom Network theory leads to results in good agreement with the experimental data.

  5. Impurities effect on the swelling of neutron irradiated beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Donne, M.D.; Scaffidi-Argentina, F. [Institut fuer Neutronenphysik und Reaktortechnik, Karlsruhe (Germany)

    1995-09-01

    An important factor controlling the swelling behaviour of fast neutron irradiated beryllium is the impurity content which can strongly affect both the surface tension and the creep strength of this material. Being the volume swelling of the old beryllium (early sixties) systematically higher than that of the more modem one (end of the seventies), a sensitivity analysis with the aid of the computer code ANFIBE (ANalysis of Fusion Irradiated BEryllium) to investigate the effect of these material properties on the swelling behaviour of neutron irradiated beryllium has been performed. Two sets of experimental data have been selected: the first one named Western refers to quite recently produced Western beryllium, whilst the second one, named Russian refers to relatively old (early sixties) Russian beryllium containing a higher impurity rate than the Western one. The results obtained with the ANFIBE Code were assessed by comparison with experimental data and the used material properties were compared with the data available in the literature. Good agreement between calculated and measured values has been found.

  6. 'Shamal' swells in the Arabian Sea and their influence along the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Aboobacker, V.M.; Vethamony, P.; Rashmi, R.

    winds in the Arabian Peninsula and northwestern Arabian Sea, which are associated with the winter shamal events. The winds during such events generate large northwesterly swells (shamal swells) in the northwestern Arabian Sea and propagate towards...

  7. Swelling of organoclays in styrene. Effect on flammability in polystyrene nanocomposites

    Directory of Open Access Journals (Sweden)

    2010-08-01

    Full Text Available In this work the effect of the compatibility between organoclays and styrene on the flammability of polystyrene/clay nanocomposites obtained through in situ incorporation was investigated. The reactions were carried out by bulk polymerization. The compatibility between organoclays and styrene was inferred from swelling of the organoclay in styrene. The nanocomposites were characterized by X-ray diffraction and Transmission Electron Microscopy. The heat release rate was obtained by Cone Calorimeter and the nanocomposites were tested by UL94 horizontal burn test. Results showed that intercalated and partially exfoliated polystyrene/clay nanocomposites were obtained depending on the swelling behavior of the organoclay in styrene. The nanocomposites submitted to UL94 burning test presented a burning rate faster than the virgin polystyrene (PS, however an increase of the decomposition temperature and an accentuated decrease on the peak of heat release of the nanocomposites were also observed compared to virgin PS. These results indicate that PS/clay nanocomposites, either intercalated or partially exfoliated, reduced the flammability approximately by the same extent, although reduced the ignition resistance of the PS.

  8. The crosslinking degree controls the mechanical, rheological, and swelling properties of hyaluronic acid microparticles.

    Science.gov (United States)

    Shimojo, Andréa Arruda Martins; Pires, Aline Mara Barbosa; Lichy, Rafael; Rodrigues, Ana Amélia; Santana, Maria Helena Andrade

    2015-02-01

    Viscosupplements, used for treating joint and cartilage diseases, restore the rheological properties of synovial fluid, regulate joint homeostasis and act as scaffolds for cell growth and tissue regeneration. Most viscosupplements are hydrogels composed of hyaluronic acid (HA) microparticles suspended in fluid HA. These microparticles are crosslinked with chemicals to assure their stability against enzyme degradation and to prolong the action of the viscosupplement. However, the crosslinking also modifies the mechanical, swelling and rheological properties of the HA microparticle hydrogels, with consequences on the effectiveness of the application. The aim of this study is to correlate the crosslinking degree (CD) with these properties to achieve modulation of HA/DVS microparticles through CD control. Because divinyl sulfone (DVS) is the usual crosslinker of HA in viscosupplements, we examined the effects of CD by preparing HA microparticles at 1:1, 2:1, 3:1, and 5:1 HA/DVS mass ratios. The CD was calculated from inductively coupled plasma spectrometry data. HA microparticles were previously sized to a mean diameter of 87.5 µm. Higher CD increased the viscoelasticity and the extrusion force and reduced the swelling of the HA microparticle hydrogels, which also showed Newtonian pseudoplastic behavior and were classified as covalent weak. The hydrogels were not cytotoxic to fibroblasts according to an MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. © 2014 Wiley Periodicals, Inc.

  9. Formation of nanoscale networks: selectively swelling amphiphilic block copolymers with CO2-expanded liquids.

    Science.gov (United States)

    Gong, Jianliang; Zhang, Aijuan; Bai, Hua; Zhang, Qingkun; Du, Can; Li, Lei; Hong, Yanzhen; Li, Jun

    2013-02-07

    Polymeric films with nanoscale networks were prepared by selectively swelling an amphiphilic diblock copolymer, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP), with the CO(2)-expanded liquid (CXL), CO(2)-methanol. The phase behavior of the CO(2)-methanol system was investigated by both theoretical calculation and experiments, revealing that methanol can be expanded by CO(2), forming homogeneous CXL under the experimental conditions. When treated with the CO(2)-methanol system, the spin cast compact PS-b-P4VP film was transformed into a network with interconnected pores, in a pressure range of 12-20 MPa and a temperature range of 45-60 °C. The formation mechanism of the network, involving plasticization of PS and selective swelling of P4VP, was proposed. Because the diblock copolymer diffusion process is controlled by the activated hopping of individual block copolymer chains with the thermodynamic barrier for moving PVP segments from one to another, the formation of the network structures is achieved in a short time scale and shows "thermodynamically restricted" character. Furthermore, the resulting polymer networks were employed as templates, for the preparation of polypyrrole networks, by an electrochemical polymerization process. The prepared porous polypyrrole film was used to fabricate a chemoresistor-type gas sensor which showed high sensitivity towards ammonia.

  10. Synthesis and characterization of fast-swelling porous superabsorbent hydrogel based on starch as a hemostatic agent.

    Science.gov (United States)

    Mirzakhanian, Zeinab; Faghihi, Khalil; Barati, Abolfazl; Momeni, Hamid Reza

    2015-01-01

    The body can't control massive bleeding without treatment. Different hemostatic agents have been prepared recently, but most of them are ineffective in severe bleeding and expensive or cause safety concerns. In this study, in order to achieve fast control of bleeding, we synthesized and characterized fast-swelling porous superabsorbent hydrogel (FSPSH) and investigated its use as a hemostatic agent. The FSPSH was prepared by grafting acrylic acid and acrylamide onto starch through free-radical polymerization in aqueous solution. The FSPSH was characterized by Fourier transform infrared, X-ray diffraction, field emission scanning electron microscope, and thermogravimetric analysis. Then, temporal swelling behavior and coagulation time experiments were used to predict the in vivo behavior of the FSPSH. The hemocompatibility of synthesized FSPSH was evaluated by hemolysis test and blood cells function. In vivo study using femoral artery injury in rat demonstrated the FSPSH's ability to aid in rapid hemostasis. Furthermore, monitoring the rat on first and seventh day after femoral artery injury also showed no harmful effect. This study indicates that FSPSH adsorbs fluid and swells, thus forms a physical barrier to blood loss. FSPSH, moreover, as hemostat is simple to use, lightweight, stable, and harmless.

  11. Swelling/deswelling of polyacrylamide gels in aqueous NaCl ...

    Indian Academy of Sciences (India)

    Swelling kinetics of water-swollen polyacrylamide (PAAm) hydrogels (WSG) was investigated in various concentrations of aqueous NaCl by macroscopic swelling measurements. For lower concentration of NaCl, WSG showed exponential swelling whereas at higher concentration of NaCl it underwent deswelling at short ...

  12. A grain-scale study of unsaturated flow in highly swelling granular materials

    NARCIS (Netherlands)

    Sweijen, Thomas

    2017-01-01

    Unsaturated flow in swelling porous materials are common and important phenomena in industrial products and earth materials; for example, in paper, hygienic products, swelling clays, and foods. Swelling causes porous media to expand and to deform, which results in a change in pore structure and thus

  13. Flakeboard thickness swelling. Part II, Fundamental response of board properties to steam injection pressing

    Science.gov (United States)

    Robert L. Geimer; Jin Heon. Kwon

    1999-01-01

    The results of this study showed that the same relative reductions in thickness swelling (TS) previously obtained with steam-injection-pressed (SIP) resinless mats are also obtained in boards bonded with 3% isocyanate resin. Reductions in thickness swelling were proportional to steam time and pressure. Thickness swelling of 40% measured in conventionally pressed boards...

  14. Exposure of natural rubber to personal lubricants--swelling and stress relaxation as potential indicators of reduced seal integrity of non-lubricated male condoms.

    Science.gov (United States)

    Sarkar Das, Srilekha; Coburn, James C; Tack, Charles; Schwerin, Matthew R; Richardson, D Coleman

    2014-07-01

    Male condoms act as mechanical barriers to prevent passage of body fluids. For effective use of condoms the mechanical seal is also expected to remain intact under reasonable use conditions, including with personal lubricants. Absorption of low molecular weight lubricant components into the material of male condoms may initiate material changes leading to swelling and stress relaxation of the polymer network chains that could affect performance of the sealing function of the device. Swelling indicates both a rubber-solvent interaction and stress relaxation, the latter of which may indicate and/or result in a reduced seal pressure in the current context. Swelling and stress relaxation of natural rubber latex condoms were assessed in a laboratory model in the presence of silicone-, glycol-, and water-based lubricants. Within 15 minutes, significant swelling (≥6 %) and stress reduction (≥12 %) of condoms were observed with 2 out of 4 silicone-based lubricants tested, but neither was observed with glycol- or water-based lubricants tested. Under a given strain, reduction in stress was prominent during the swelling processes, but not after the process was complete. Lubricant induced swelling and stress relaxation may loosen the circumferential stress responsible for the mechanical seal. Swelling and stress relaxation behavior of latex condoms in the presence of personal lubricants may be useful tests to identify lubricant-rooted changes in condom-materials. For non-lubricated latex condoms, material characteristics--which are relevant to failure--may change in the presence of a few silicone-based personal lubricants. These changes may in turn induce a loss of condom seal during use, specifically at low strain conditions. Published by Elsevier Inc.

  15. Behaviorism

    Science.gov (United States)

    Moore, J.

    2011-01-01

    Early forms of psychology assumed that mental life was the appropriate subject matter for psychology, and introspection was an appropriate method to engage that subject matter. In 1913, John B. Watson proposed an alternative: classical S-R behaviorism. According to Watson, behavior was a subject matter in its own right, to be studied by the…

  16. Influence of the standard free energy on swelling kinetics of gels.

    Science.gov (United States)

    Keener, James P; Sircar, Sarthok; Fogelson, Aaron L

    2011-04-01

    Classical theories of gel swelling employ the mixing free energy, thereby ignoring any effects of the free energy of the pure phases,i.e., the polymer standard free energy. In this paper we present a model for the swelling kinetics of gels that incorporates the free energy, including the polymer standard free energy. We provide a complete analysis of how the swelling kinetics and stable states and sizes of the swelled gel depends on the free energy parameters and show that theories that use only the mixing free energy cannot correctly describe equilibrium states or the swelling kinetics. ©2011 American Physical Society

  17. Controlling morphology in swelling-induced wrinkled surfaces

    Science.gov (United States)

    Breid, Derek Ronald

    Wrinkles represent a pathway towards the spontaneous generation of ordered surface microstructure for applications in numerous fields. Examples of highly complex ordered wrinkle structures abound in Nature, but the ability to harness this potential for advanced material applications remains limited. This work focuses on understanding the relationship between the patterns on a wrinkled surface and the experimental conditions under which they form. Because wrinkles form in response to applied stresses, particular attention is given to the nature of the stresses in a wrinkling surface. The fundamental insight gained was then utilized to account for observed wrinkle formation phenomena within more complex geometric and kinetic settings. In order to carefully control and measure the applied stresses on a wrinkling film, a swelling-based system was developed using poly(dimethylsiloxane) (PDMS), surface-oxidized with a UV-ozone treatment. The swelling of the oxidized surface upon exposure to an ethanol vapor atmosphere was characterized using beam-bending experiments, allowing quantitative measurements of the applied stress. The wrinkle morphologies were characterized as a function of the overstress, defined as the ratio of the applied swelling stress to the critical buckling stress of the material. A transition in the dominant morphology of the wrinkled surfaces from dimple patterns to ridge patterns was observed at an overstress value of ˜2. The pattern dependence of wrinkles on the ratio of the principal stresses was examined by fabricating samples with a gradient prestress. When swollen, these samples exhibited a smooth morphological transition from non-equibiaxial to equibiaxial patterns, with prestrains as low as 2.5% exhibiting non-equibiaxial characteristics. This transition was seen both in samples with low and high overstresses. To explore the impact of these stress states in more complex geometries, wrinkling hemispherical surfaces with radii of curvature

  18. Ultrasonographic evaluation of inflammatory swellings of buccal space

    Directory of Open Access Journals (Sweden)

    Srinivas K

    2009-01-01

    Full Text Available Objectives : The main objective of the study was a to differentiate cellulitis and abscess in buccal space region, b to study the ultrasonographic anatomy of cheek region and c to investigate the use of ultrasound in the diagnosis of inflammatory swellings of cheek region. Patients and Methods : The study consisted of 25 patients with unilateral buccal space inflammatory swellings of odontogenic origin. The contra lateral side was used as control. Toshiba ultrasonographic device with a linear array transducer (5-8 MHz was used. The areas of interest were scanned under both transverse and longitudinal sections and were interpreted by a single observer. The clinical diagnosis of cellulitis or abscess was confirmed by the absence or presence of pus respectively both sonographically and by aspiration. Also various anatomical structures present in buccal space were studied. Results : Clinically 23(92% were diagnosed as buccal space abscess and 2 (8% were cellulitis. Ultrasonographically and therapeutically 24 (96% were buccal space abscess and 1 (4% was cellulits. The sensitivity of clinical criteria over ultrasonographic diagnosis was 96% with a specificity of 100%. Also the cheek thickness in males and females varied from 8.2 to 17.1mm with a mean of 11.6mm±2.1 (SD and 8.2 mm to 14.2 mm with a mean of 11±1.8 (SD. The subcutaneous tissue appeared moderately echogenic, buccinator - highly echogenic, deep adipose tissue - less echogenic and parotid duct was appreciated as a thin hyperechogenic band crossing the buccinator muscle. Buccal space, masticator space and parotid space were appreciated. Conclusion : This study supports the ultrasonographic method of imaging of orofacial inflammatory swellings with high sensitivity and specificity. This imaging modality can also help in aspiration of pus in different spaces. We have described the ultrasonographic anatomy of the above mentioned spaces which can help a beginner in this field.

  19. Water Migration and Swelling in Bentonite Quantified using Neutron Radiography

    Science.gov (United States)

    Vial, A.; DiStefano, V. H.; Perfect, E.; Hale, R. E.; Anovitz, L. M.; McFarlane, J.

    2016-12-01

    Permanent disposal of radioactive waste remains a critical challenge for the nation's energy future. All disposal system concepts include interfaces between engineered systems and natural materials requiring extensive characterization. Bentonite is often used to buffer subsurface disposal systems from geologic media containing ground water. Bentonite characterization experiments were carried out using the CG-1D neutron imaging beam line at Oak Ridge National Laboratory. Dry bentonite was packed into vertically-oriented aluminum cylinders. Water was ponded on the top surface of each packed cylinder. Images were acquired at 2 min intervals using dynamic neutron radiography. The detector consisted of stacked neutron sensitive microchannel plates above a quad Timepix readout with a 28 x 28 mm2 field of view. The spatial resolution of the detector was 55 μm. Raw neutron radiographs were imported into ImageJ and normalized with respect to the initial completely dry state. The wetting process was 1-dimensional, and vertical intensity profiles were computed by averaging pixel rows. The vertical distance between the clay-water interface and the wetting front could then be determined as a function of time. Depth of water infiltration increased linearly with the square root of time, yielding a sorptivity value of 0.75 (± 0.070) mm/min0.5. Swelling occurred in the form of upward movement of clay particles into the ponded water over time. The resulting low density assemblage was discernable by normalizing the raw profiles with respect to the intensity profile immediately after ponding. The packed clay-water interface was clearly visible in the normalized profiles, and swelling was quantified as the height of the low density assemblage above the original interface. Swelling occurred as a linear function of time, at a rate of 0.054 (± 0.020) mm/min. Further experiments of this type are planned under variable temperature and pressure regimes applicable to subsurface

  20. Enhanced Swelling and Responsive Properties of Pineapple Peel Carboxymethyl Cellulose-g-poly(acrylic acid-co-acrylamide) Superabsorbent Hydrogel by the Introduction of Carclazyte.

    Science.gov (United States)

    Dai, Hongjie; Huang, Huihua

    2017-01-25

    The superabsorbent hydrogels were synthesized by grafting acrylic acid and acrylamide onto pineapple peel carboxymethyl cellulose and effect of carclazyte introduction was compared. The structure and morphology of the superabsorbents were investigated by Fourier transform infrared spectroscopy, X-ray diffraction, and field emission scanning electron microscopy. Swelling behaviors of the superabsorbents were investigated in distilled water, 0.9% NaCl solution, various salt and pH solutions, as well as surfactant solutions and simulated physiological fluids. The swelling dynamic mechanism of the superabsorbents was explained well by Fickian diffusion and Schott's pseudo-second-order models. The introduction of carclazyte effectively improved the swelling capacity of the superabsorbents in various solutions as well as its salt- and pH-sensitivity. The prepared superabsorbents also exhibited excellent sensitivities to various surfactant solutions and simulated physiological fluids, showing potential applications in the biomaterials field.

  1. Upper limb swelling following mastectomy: lymphedema or not?

    Science.gov (United States)

    Armer, Jane

    2007-04-01

    Having experienced an excisional biopsy, sentinel lymph node biopsy, and mastectomy, BH is at lifetime risk of developing post-breast cancer lymphedema in the arm on the side where her breast cancer was treated. She has two additional risk factors, among those documented in the literature: history of an infection (specifically a systemic infection, significant in that it required hospitalization for intravenous antibiotics) in the postsurgery period, and a moderate increase in bilateral limb volume and weight (body mass index) over the months and years following the breast cancer diagnosis. Further, the patient-reported transient hand swelling on the affected side and gradual weight increase are cues indicating a need for patient vigilance and careful monitoring by the health-care team. Preventing future infections, managing weight at an optimal level, and preventing trauma or injury to the affected arm and chest are important self-management precautions to reduce risk of chronic lymphedema development. BH needs continued support in reviewing evidence-based risk-reduction guidelines and understanding ways to apply them to her lifestyle. In the absence of preoperative baseline or contralateral limb measurements (with circumferences or perometry or water displacement), assessment of limb change at a level identified as diagnostic of lymphedema (commonly, 200-mL volume or 2-cm girth increase from baseline or as compared to the contralateral limb) is very challenging. Without bilateral preop limb measurements for baseline and contralateral limb comparisons, BH might have been diagnosed with lymphedema at postop or at 48 months, when both limbs increased symmetrically. Symptom assessment is also crucial, as symptom report of heaviness and swelling is found to be associated with limb volume changes indicative of lymphedema. Transient hand swelling may be evidence of latent lymphedema and cause for increased risk-reduction education and vigilance in assessment for

  2. Kimura's Disease: A Rare Cause of Postauricular Swelling

    Directory of Open Access Journals (Sweden)

    Suman Kumar Das

    2017-04-01

    Full Text Available Introduction Kimura’s Disease is a chronic inflammatory disorder of lymph node which is very rare in Indian population. Case Report A 15 year old boy with multiple postauricular swelling for 18 months presenting in OPD and diagnosed having eosinophilia. Then excision biopsy was taken, which indicates Kimura’s Disease. Patient was treated with high dose of corticosteroid. Conclusion Kimura’s disease, though rare should be kept in mind for treating a patient with lymphadenopathy with eosinophilia or high IgE level, because it can spare the patient unnecessary invasive procedure.

  3. Gamma radiation synthesis of rapid swelling superporous polyacrylamide hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Francis, Sanju [Radiation Technology Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)], E-mail: sanju@barc.gov.in; Mitra, D.; Dhanawade, B.R.; Varshney, Lalit; Sabharwal, Sunil [Radiation Technology Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2009-11-15

    In this report a simple route for gamma radiation induced synthesis of superporous hydrogel (SPH) is described. Conventional SPH synthesis requires foaming and cross-linking reactions to take place simultaneously. However, in radiation synthesis it is difficult to introduce foaming during the cross-linking reactions. In order to overcome this limitation, the foaming and radiation cross-linking reactions were decoupled and carried out in two stages. The polyacrylamide SPH synthesized by this approach has very fast swelling kinetics compared to the non-porous hydrogel.

  4. Gamma radiation synthesis of rapid swelling superporous polyacrylamide hydrogels

    Science.gov (United States)

    Francis, Sanju; Mitra, D.; Dhanawade, B. R.; Varshney, Lalit; Sabharwal, Sunil

    2009-11-01

    In this report a simple route for gamma radiation induced synthesis of superporous hydrogel (SPH) is described. Conventional SPH synthesis requires foaming and cross-linking reactions to take place simultaneously. However, in radiation synthesis it is difficult to introduce foaming during the cross-linking reactions. In order to overcome this limitation, the foaming and radiation cross-linking reactions were decoupled and carried out in two stages. The polyacrylamide SPH synthesized by this approach has very fast swelling kinetics compared to the non-porous hydrogel.

  5. Arteriovenous malformations in the differential diagnosis of palatal swellings

    Science.gov (United States)

    Ozden, Bora; Bas, Burcu; Duran, Hatice; Celenk, Peruze; Gunhan, Omer

    2016-01-01

    An arteriovenous malformation (AVM) is composed of abnormal communications between arteries and veins without the normal intervening capillary bed. AVM of the head and neck is a rare vascular anomaly. We present here an unusual case of AVM with the size of 4x3 cm at the left posterior palatal area. Incisionel biopsy revealed AVM. Resection of the lesion following angiography was suggested to the patient however, he refused the treatment. The patient was considered to be under control. AVM should always be kept in mind in the differential diagnosis of palatal swellings. PMID:28955556

  6. Genital tuberculosis: A rare cause of vulvovaginal discharge and swelling

    Directory of Open Access Journals (Sweden)

    Malak Alhakeem

    2013-09-01

    Full Text Available Herein, we report a patient with vulvovaginal tuberculosis (TB presented with a vulvovaginal mass and vaginal discharge.The diagnosis was made by both histopathological examination of the excised specimen which was clinicallysuspected to be a malignant lesion and cervical smear culture positivity for Mycobacterium tuberculosis. The patientwas prescribed a full course of anti-tuberculous drugs. In this report, we discuss the genital TB and its gynecologicaleffects in the light of medical literature. J Microbiol Infect Dis 2013; 3(3: 140-142Key words: Genital tuberculosis, vulvovaginal swelling

  7. Detection of swelling of single isolated mitochondrion with optical microscopy

    Science.gov (United States)

    Morikawa, Daisuke; Kanematsu, Keita; Shibata, Takahiro; Haseda, Keisuke; Umeda, Norihiro; Ohta, Yoshihiro

    2014-01-01

    Volume regulation under osmotic loading is one of the most fundamental functions in cells and organelles. However, the effective method to detect volume changes of a single organelle has not been developed. Here, we present a novel technique for detecting volume changes of a single isolated mitochondrion in aqueous solution based on the transmittance of the light through the mitochondrion. We found that 70% and 21% of mitochondria swelled upon addition of a hypotonic solution and Ca2+, respectively. These results show the potential of the present technique to detect the physiological volume changes of individual small organelles such as mitochondria. PMID:24688818

  8. Simultaneous measurement of CO2 sorption and swelling of phosphate-based ionic liquid

    Directory of Open Access Journals (Sweden)

    Junfeng Wang

    2016-10-01

    Full Text Available The development of alternative CO2 capture solvents such as ionic liquids (ILs and nanoparticle organic hybrid materials (NOHMs have provided interesting options for CO2 capture. In this study, CO2 interactions with 1,3-dimethylimidazolium dimethylphosphate ([MMIM]DMP, 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM]DMP and 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM]DEP that contain inorganic ester groups based on phosphate, were investigated using ATR FT-IR spectroscopy. CO2-induced swelling, CO2 diffusivity and CO2 capture capacity were simultaneously measured to identify CO2 capture mechanisms, kinetics and diffusion behaviors as a function of the alkyl chain length of the cation. Henry's law constants of CO2 were found to be in the range of 4–11 MPa, which is in agreement with those reported in other studies. Keywords: CO2 capture, ATR FT-IR spectroscopy, Ionic liquids, Mechanism, Diffusivity

  9. Ulcerated anterior maxillary swelling showing radiopaque bodies on cone beam computed tomography.

    Science.gov (United States)

    Costa, Fábio Wildson Gurgel; Vasconcelos, Marcelo Gadelha; de Queiroz, Lélia Maria Guedes; de Queiroz, Sormani Bento Fernandes; de Menezes, Alynne Vieira; Soares, Eduardo Costa Studart; Pereira, Karuza Maria Alves

    2013-11-01

    The calcifying epithelial odontogenic tumor (CEOT), also known as Pindborg tumor, is a rare benign tumor of epithelial origin of locally aggressive behavior, which represents less than 1% of all odontogenic tumors affecting the oral cavity. The lesion usually presents as a nonulcerated painless mass of slow growth, commonly affecting the posterior region of the mandible. Depending on the stages of development, CEOTs may present variable radiographic appearances. To date, a few number of cases affecting the anterior maxillary region have been published in the English-language literature. This article describes an interesting and rare case of an anterior ulcerated maxillary swelling diagnosed as a CEOT based on clinical, cone beam computed tomography and pathologic findings. Functional results were obtained with the surgical approach, and no recurrence of the lesion during a 2-year follow-up period was observed.

  10. Assembly, characterization and swelling kinetics of Ag nanoparticles in PDMAA-g-PVA hydrogel networks

    Energy Technology Data Exchange (ETDEWEB)

    Luo Yanling, E-mail: luoyanl@snnu.edu.cn [Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Materials Science, Shaanxi Normal University, No. 199, South Chang' an Road, Xi' an 710062 (China); Wei Qingbo [Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Materials Science, Shaanxi Normal University, No. 199, South Chang' an Road, Xi' an 710062 (China); Xu Feng, E-mail: fengxu@snnu.edu.cn [Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Materials Science, Shaanxi Normal University, No. 199, South Chang' an Road, Xi' an 710062 (China); Chen Yashao; Fan Lihua; Zhang Changhu [Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Materials Science, Shaanxi Normal University, No. 199, South Chang' an Road, Xi' an 710062 (China)

    2009-12-15

    A series of poly(N,N-dimethylacrylamide)-g-poly(vinyl alcohol) (PDMAA-g-PVA) graft hydrogel networks were designed and prepared via a free radical polymerization route initiated by a PVA-(NH{sub 4}){sub 2}Ce(NO{sub 3}){sub 6} redox reaction. Silver nanoparticles with high stability and good distribution behavior have been self-assembled by using these hydrogel networks as a nanoreactor and in situ reducing system. Meanwhile the PDMAA or PVA chains can efficiently act as stabilizing agents for the Ag nanoparticles in that Ag{sup +} would form complex via oxygen atom and nitrogen atom, and form weak coordination bonds, thus astricting Ag{sup +}. The structure of the PDMAA-g-PVA/Ag was characterized by a Fourier transform infrared spectroscope (FTIR). The morphologies of pure PDMAA-g-PVA hydrogels and PDMAA-g-PVA/Ag nanocomposite ones were observed by a scanning electron microscopy (SEM) and transmission electron microscope (TEM). TEM micrographs revealed the presence of nearly spherical and well-separated Ag nanoparticles with diameters ranging from 10 to 20 nm, depending on their reduction routes. XRD results showed all relevant Bragg's reflection for crystal structure of Ag nanoparticles. UV-vis studies apparently showed the characteristic surface plasmon band at 410-440 nm for the existence of Ag nanoparticles within the hydrogel matrix. The swelling kinetics demonstrated that the transport mechanism belongs to non-Fickian mode for the PDMAA-g-PVA hydrogels and PDMAA-g-PVA/Ag nanocomposite ones. With increasing the DMAA proportion, the r{sub 0} and S{sub {infinity} }are enhanced for each system. The assembly of Ag nanoparticles and the swelling behavior may be controlled and modulated by means of the compositional ratios of PVA to DMAA and reduction systems.

  11. Textureless Macula Swelling Detection with Multiple Retinal Fundus Images

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Tobin Jr, Kenneth William [ORNL; Grisan, Enrico [University of Padua, Padua, Italy; Favaro, Paolo [Heriot-Watt University, Edinburgh; Ruggeri, Alfredo [University of Padua, Padua, Italy; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2010-01-01

    Retinal fundus images acquired with non-mydriatic digital fundus cameras are a versatile tool for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relatively low cost, these cameras can be employed by operators with limited training for telemedicine or Point-of-Care applications. We propose a novel technique that uses uncalibrated multiple-view fundus images to analyse the swelling of the macula. This innovation enables the detection and quantitative measurement of swollen areas by remote ophthalmologists. This capability is not available with a single image and prone to error with stereo fundus cameras. We also present automatic algorithms to measure features from the reconstructed image which are useful in Point-of-Care automated diagnosis of early macular edema, e.g., before the appearance of exudation. The technique presented is divided into three parts: first, a preprocessing technique simultaneously enhances the dark microstructures of the macula and equalises the image; second, all available views are registered using non-morphological sparse features; finally, a dense pyramidal optical flow is calculated for all the images and statistically combined to build a naiveheight- map of the macula. Results are presented on three sets of synthetic images and two sets of real world images. These preliminary tests show the ability to infer a minimum swelling of 300 microns and to correlate the reconstruction with the swollen location.

  12. Controlled swelling and adsorption properties of polyacrylate/montmorillonite composites

    Energy Technology Data Exchange (ETDEWEB)

    Natkanski, Piotr [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Kustrowski, Piotr, E-mail: kustrows@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Bialas, Anna; Piwowarska, Zofia [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Michalik, Marek [Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Krakow (Poland)

    2012-10-15

    A series of novel polyacrylate/montmorillonite composites was synthesized by in situ polymerization in aqueous slurry of clay. Dissociated (obtained by adding ammonium or sodium hydroxide) and undissociated forms of acrylic acid were used as monomers in the hydrogel synthesis. The structure and composition of the samples were studied by powder X-ray diffraction, diffuse reflectance infra-red Fourier transform spectroscopy, thermogravimetry and elemental analysis. It has been found that the kind of monomer influences strongly the location of a polymer chain in the formed composite. Complete intercalation of hydrogel into the interlayer space of montmorillonite was observed for sodium polyacrylate, whereas polyacrylic acid and ammonium polyacrylate mainly occupied the outer surface of the clay. The position of hydrogel determined the swelling and adsorption properties of the studied composites. The important factor influencing the kinetics of Fe(III) cation adsorption was pH. The analysis of adsorption isotherms allowed to propose the mechanism of Fe(III) cation adsorption. Highlights: Black-Right-Pointing-Pointer Polyacrylate hydrogels can be introduced into the interlayers of clay. Black-Right-Pointing-Pointer The position of hydrogel in the composite depends on the polymer type. Black-Right-Pointing-Pointer Ammonium polyacrylate places outside the clay, sodium one is intercalated into it. Black-Right-Pointing-Pointer Swelling and adsorption capacities can be controlled by the polymer position. Black-Right-Pointing-Pointer High adsorption efficiency in Fe(III) removal was observed.

  13. Gibbs Ensemble Simulations of the Solvent Swelling of Polymer Films

    Science.gov (United States)

    Gartner, Thomas; Epps, Thomas, III; Jayaraman, Arthi

    Solvent vapor annealing (SVA) is a useful technique to tune the morphology of block polymer, polymer blend, and polymer nanocomposite films. Despite SVA's utility, standardized SVA protocols have not been established, partly due to a lack of fundamental knowledge regarding the interplay between the polymer(s), solvent, substrate, and free-surface during solvent annealing and evaporation. An understanding of how to tune polymer film properties in a controllable manner through SVA processes is needed. Herein, the thermodynamic implications of the presence of solvent in the swollen polymer film is explored through two alternative Gibbs ensemble simulation methods that we have developed and extended: Gibbs ensemble molecular dynamics (GEMD) and hybrid Monte Carlo (MC)/molecular dynamics (MD). In this poster, we will describe these simulation methods and demonstrate their application to polystyrene films swollen by toluene and n-hexane. Polymer film swelling experiments, Gibbs ensemble molecular simulations, and polymer reference interaction site model (PRISM) theory are combined to calculate an effective Flory-Huggins χ (χeff) for polymer-solvent mixtures. The effects of solvent chemistry, solvent content, polymer molecular weight, and polymer architecture on χeff are examined, providing a platform to control and understand the thermodynamics of polymer film swelling.

  14. Polymer-Induced Swelling of Solid-Supported Lipid Membranes

    Science.gov (United States)

    Kreuzer, Martin; Trapp, Marcus; Dahint, Reiner; Steitz, Roland

    2015-01-01

    In this paper, we study the interaction of charged polymers with solid-supported 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) membranes by in-situ neutron reflectivity. We observe an enormous swelling of the oligolamellar lipid bilayer stacks after incubation in solutions of poly(allylamine hydrochloride) (PAH) in D2O. The positively charged polyelectrolyte molecules interact with the lipid bilayers and induce a drastic increase in their d-spacing by a factor of ~4. Temperature, time, and pH influence the swollen interfacial lipid linings. From our study, we conclude that electrostatic interactions introduced by the adsorbed PAH are the main cause for the drastic swelling of the lipid coatings. The DMPC membrane stacks do not detach from their solid support at T > Tm. Steric interactions, also introduced by the PAH molecules, are held responsible for the stabilizing effect. We believe that this novel system offers great potential for fundamental studies of biomembrane properties, keeping the membrane’s natural fluidity and freedom, decoupled from a solid support at physiological conditions. PMID:26703746

  15. In situ characterization of structural dynamics in swelling hydrogels.

    Science.gov (United States)

    Guzman-Sepulveda, J R; Deng, J; Fang, J Y; Dogariu, A

    2016-07-06

    Characterizing the structural morphology and the local viscoelastic properties of soft complex systems raises significant challenges. Here we introduce a dynamic light scattering method capable of in situ, continuous monitoring of structural changes in evolving systems such as swelling gels. We show that the inherently non-stationary dynamics of embedded probes can be followed using partially coherent radiation, which effectively isolates only single scattering contributions even during the dramatic changes in the scattering regime. Using a simple and robust experimental setup, we demonstrate the ability to continuously monitor the structural dynamics of chitosan hydrogels formed by the Ag(+) ion-triggered gelation during their long-term swelling process. We demonstrate that both the local viscoelastic properties of the suspending medium and an effective cage size experienced by diffusing probe particles loaded into the hydrogel can be recovered and used to describe the structural dynamics of hydrogels with different levels of cross-linking. This characterization capability is critical for defining and controlling the hydrogel performance in different biomedical applications.

  16. Depleted swell root beneath the Cape Verde Islands

    Science.gov (United States)

    Lodge, Alexandra; Helffrich, George

    2006-06-01

    The hotspot swell—an area of uplifted bathymetry or topography surrounding regional volcanism—is a defining hotspot characteristic, yet its origin is poorly understood. To test current ideas about swell formation, we studied the crust and shallow mantle structure of the Cape Verdes in a passive seismic experiment. The Cape Verde Islands are ˜450 km west of Senegal in the tropical Atlantic Ocean and are on the southwest flank of the Cape Verde Rise, the largest bathymetric anomaly in the oceans, rising ˜2 km above the surrounding seafloor (Crough, 1982). The archipelago occupies a unique position, an approximately stationary one in the hotspot frame of reference (Gripp and Gordon, 2002) and therefore with respect to the melting source believed to have produced it. Here we present an analysis of compressional to shear (P to S) converted seismic phases, recorded on a temporary network of seismograph stations on the Cape Verde Islands, that indicate a crust thickened to 22 km is underlain by a high-velocity, low-density layer, which overlies a zone of low shear-wave velocity starting at ˜80 km depth. We also measured shear-wave splitting delay times for teleseismic SKS phases, which are ˜0.81 s, compatible with an origin in this same layer. We interpret these observations as effects of hotspot melting, which produces a thickened crust and a depleted swell root that buoys the ocean floor and spreads laterally as it grows over time.

  17. Evaluation of swell behaviour of expansive clays from specific moisture capacity

    Directory of Open Access Journals (Sweden)

    Pino Alejandro

    2016-01-01

    Full Text Available Current swell characterization techniques used to interpret the mechanical volume change occurring during the swelling process are not successful due to lack of inclusion of influential properties. Accurate prediction of swelling behaviour allows us to design more efficiently and with better reliability. This research aims at developing a more comprehensive framework to predict swell potential. Laboratory studies are conducted on five natural expansive soils with different degree of expansiveness. Initial studies include determination of basic soil characterization, swell strains and swell pressures at their compacted state along with their inherent mineralogy. Later, replicate samples were studied for soil water characteristic curves using standard pressure cell apparatus and filter paper techniques. The path traversed by the specimen during swelling process is representative of the soil water characteristic curve of the same specimen. Hence, studies are pursued to understand the relationship between degree of expansiveness and the specific moisture capacity relative to that particular range of suction head. Test results showed that the degree of expansion represented by swelling strain or swelling pressure is proportional to the specific moisture capacity determined during the swelling process.

  18. Non-monotonic swelling of surface grafted hydrogels induced by pH and/or salt concentration

    Energy Technology Data Exchange (ETDEWEB)

    Longo, Gabriel S. [Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CONICET, La Plata (Argentina); Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208 (United States); Olvera de la Cruz, Monica [Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208 (United States); Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Szleifer, I., E-mail: igal@northwestern.edu [Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States)

    2014-09-28

    We use a molecular theory to study the thermodynamics of a weak-polyacid hydrogel film that is chemically grafted to a solid surface. We investigate the response of the material to changes in the pH and salt concentration of the buffer solution. Our results show that the pH-triggered swelling of the hydrogel film has a non-monotonic dependence on the acidity of the bath solution. At most salt concentrations, the thickness of the hydrogel film presents a maximum when the pH of the solution is increased from acidic values. The quantitative details of such swelling behavior, which is not observed when the film is physically deposited on the surface, depend on the molecular architecture of the polymer network. This swelling-deswelling transition is the consequence of the complex interplay between the chemical free energy (acid-base equilibrium), the electrostatic repulsions between charged monomers, which are both modulated by the absorption of ions, and the ability of the polymer network to regulate charge and control its volume (molecular organization). In the absence of such competition, for example, for high salt concentrations, the film swells monotonically with increasing pH. A deswelling-swelling transition is similarly predicted as a function of the salt concentration at intermediate pH values. This reentrant behavior, which is due to the coupling between charge regulation and the two opposing effects triggered by salt concentration (screening electrostatic interactions and charging/discharging the acid groups), is similar to that found in end-grafted weak polyelectrolyte layers. Understanding how to control the response of the material to different stimuli, in terms of its molecular structure and local chemical composition, can help the targeted design of applications with extended functionality. We describe the response of the material to an applied pressure and an electric potential. We present profiles that outline the local chemical composition of the

  19. Prospective evaluation of pain, swelling, and disability from copperhead envenomation.

    Science.gov (United States)

    Roth, Brett; Sharma, Kapil; Onisko, Nancy; Chen, Tiffany

    2016-03-01

    In light of the existing controversy regarding antivenin treatment for copperhead envenomation, a more detailed analysis of the disability from this species is needed. Our objective was to prospectively determine the duration of pain, swelling, and functional disability, i.e., residual venom effects, in patients with copperhead envenomation. Patients with venomous snakebite reported to the North Texas Poison Center between April 2009 and November 2011 were assessed. Patients with confirmed envenomations were contacted by a specialist in poison information. Day zero was the day of the bite and verbal phone consent for study enrollment was obtained at that time. The patient (or their guardian) was contacted by phone daily thereafter, and asked to rate their pain, edema/swelling, and disability using the modified DASH and LEFS scales. Patients were followed to resolution of all symptoms or return to baseline. About 104 cases of venomous snakebite were followed; of which 17 were excluded due to being a dry bites (5) or for having insufficient data during follow-up (11) or due to coagulopathy (1). Overall, residual venom effects from copperhead bites for most patients last between 7 and 13 days. Median time to complete pain resolution was 7 days (mean = 10.7 days). Median length of time to resolution of swelling was 10 days (mean = 13 days) and median length of time to resolution of functional disability was 9 days (mean = 12.2 days). Residual venom effects from copperhead envenomation in this study had a slightly shorter duration than some other studies. Data are skewed due to outliers where residual venom effects lasted for up to 89 days. Initial reoccurrence of some symptoms may be seen. Antivenom (AV) is currently being used for a large percentage of patients with copperhead envenomation. Finally, no differences in duration of venom effects were seen based on age or location of bite. Our study suggests that residual venom effects from copperhead

  20. Feet swelling in a multistage ultraendurance triathlete: a case study

    Directory of Open Access Journals (Sweden)

    Knechtle B

    2015-10-01

    Full Text Available Beat Knechtle,1 Matthias Alexander Zingg,2 Patrizia Knechtle,1 Thomas Rosemann,2 Christoph Alexander Rüst2 1Gesundheitszentrum St Gallen, St Gallen, 2Institute of Primary Care, University of Zurich, Zurich, Switzerland Abstract: Recent studies investigating ultraendurance athletes showed an association between excessive fluid intake and swelling of the lower limbs such as the feet. To date, this association has been investigated in single-stage ultraendurance races, but not in multistage ultraendurance races. In this case study, we investigated a potential association between fluid intake and feet swelling in a multistage ultraendurance race such as a Deca Iron ultratriathlon with ten Ironman triathlons within 10 consecutive days. A 49-year-old well-experienced ultratriathlete competed in autumn 2013 in the Deca Iron ultratriathlon held in Lonata del Garda, Italy, and finished the race as winner within 129:33 hours:minutes. Changes in body mass (including body fat and lean body mass, foot volume, total body water, and laboratory measurements were assessed. Food and fluid intake during rest and competing were recorded, and energy and fluid turnovers were estimated. During the ten stages, the volume of the feet increased, percentage body fat decreased, creatinine and urea levels increased, hematocrit and hemoglobin values decreased, and plasma [Na+] remained unchanged. The increase in foot volume was significantly and positively related to fluid intake during the stages. The poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. This case report shows that the volume of the foot increased during the ten stages, and the increase in volume was significantly and positively related to fluid intake during the stages. Furthermore, the poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. The continuous feet swelling during the race was

  1. The effect of salt concentration on swelling power, rheological properties and saltiness perception of waxy, normal and high amylose maize starch.

    Science.gov (United States)

    Zhang, Xudong; Guo, Dongwei; Xue, Jiquan; Yanniotis, Stavros; Mandala, Ioanna

    2017-10-18

    The effect of salt concentration on swelling power, rheological properties and saltiness perception of waxy, normal and high amylose maize starch was investigated. The swelling power decreased with increasing salt concentration from 0% to 2.0% among all starch samples. Waxy starch showed the highest swelling power at different salt levels, while high amylose starch showed the least swelling power. The salt addition increased the gelatinization temperature of waxy starch and normal starch from 71.3 °C to 77.1 °C and from 72.3 °C to 78.2 °C. Their storage modulus (G'), loss modulus (G''), and viscosity values at lower salt concentration were greater than those at higher salt concentration. The increasing tan δ of waxy and normal starch against frequency sweep indicated liquid-like behavior, while high amylose starch exhibited decreasing tan δ indicating solid-like behavior as it was difficult to gelatinize. When sensory evaluation was conducted by trained panelists, it was found that high amylose starch displayed the highest initial saltiness and in-mouth saltiness intensity, accompanied by the greatest thickness, lubrication and stickiness, while waxy starch displayed the lowest values for saltiness perception and mouthfeel.

  2. Swelling and electro-osmotic properties of cation-exchange membranes with different structures in methanol-water media

    Science.gov (United States)

    Barragán, V. M.; Villaluenga, J. P. G.; Godino, M. P.; Izquierdo-Gil, M. A.; Ruiz-Bauzá, C.; Seoane, B.

    Electro-osmosis experiments through three cation-exchange membranes with different morphology and similar electric properties have been performed using methanol-water solutions under different experimental conditions. The influence on the electro-osmotic transport of the percentage of methanol on solvent with two different electrolytes, NaCl and LiCl, has been studied. The experimental results show that the presence of methanol in the solutions affects strongly the electro-osmotic flow, and this influence is different depending on the membrane morphology. Correlations among electro-osmotic permeability, swelling behavior, and cell resistance are studied for these membrane systems at different percentages of methanol in solvent.

  3. Water drainage in mine roadways with swelling floors

    Energy Technology Data Exchange (ETDEWEB)

    Martyushev, V.S.; Losev, G.F.; Danilov, B.G. (Shakhta imeni Leninskogo Komsomola Ukrainy (USSR))

    1989-09-01

    Describes the situation at a Pavlograd mine (W. Donbass) where the water influx into mine roadways is 70 m{sup 3}/h. Over a period of years, zones of large and small cracks have appeared around the main roadways (480 m level) through support replacement and dinting work. Some of the water entering the roadway flows away along these cracks parallel to the roadway. The flow rate by this means can reach 5 m{sup 3}/h. Water flowing in this way damages shaft linings and causes additional floor swelling. It may also escape into water conducting strata (coal, sandstone) and flood lower lying roadways. The problem is difficult to control, but sometimes the crack systems in roadway floors may be used to advantage to drain water out of influx hazard zones.

  4.  Soft Tissue Swelling at the Subscapular Region

    Directory of Open Access Journals (Sweden)

    Masoud Al Kindi

    2012-03-01

    Full Text Available A 38-year-old female presented with a longstanding painless swelling overlying the scapula on the right side and has been gradually increasing in size with occasional episodes of pain radiating to the right arm. The clinical diagnosis was a soft tissue tumor. MRI was reported as suggestive of irregular fibro-fatty tissue with muscular infiltration and inflammation. Fine needle aspiration (FNA retrieved a paucicellular aspirate with a few clusters of adipocytes. The diagnosis was a lipomatous lesion and excision was advised for histopathological examination. The intraoperative findings showed the tumor located deep into the rhomboids and latissimus dorsi and extending deep into the right scapula. The excised specimen was sent for histopathological examination. 

  5. Magnetic resonance imaging of clays: swelling, sedimentation, dissolution

    Science.gov (United States)

    Dvinskikh, Sergey; Furo, Istvan

    2010-05-01

    measure of clay distribution in extended samples during different physical processes such as swelling, dissolution, and sedimentation on the time scale from minutes to years [1-3]. To characterize the state of colloids that form after/during clay swelling the water self-diffusion coefficient was measured on a spatially resolved manner. Both natural clays and purified and ion-exchanged montmorillonite clays were investigated. The primary variables were clay composition and water ionic strength. These results have a significant impact for engineering barriers for storage of spent nuclear fuel where clay erosion by low salinity water must be addressed. Presented methods were developed under the motivation of using bentonite clays as a buffer medium to build in-ground barriers for the encapsulation of radioactive waste. Nevertheless, the same approaches can be found suitable in other applications in soil and environmental science to study other types of materials as they swell, dissolve, erode, or sediment. Acknowledgements: This work has been supported by the Swedish Nuclear Fuel and Waste Management Co (SKB) and the Swedish Research Council VR. [1] N. Nestle, T. Baumann, R. Niessner, Magnetic resonance imaging in environmental science. Environ. Sci. Techn. 36 154A (2002). [2] S. V. Dvinskikh, K. Szutkowski, I. Furó. MRI profiles over a very wide concentration ranges: application to swelling of a bentonite clay. J. Magn. Reson. 198 146 (2009). [3] S. V. Dvinskikh, I. Furó. Magnetic resonance imaging and nuclear magnetic resonance investigations of bentonite systems. Technical Report, TR-09-27, SKB (2009), www.skb.se.

  6. A study of the causes of bilateral optic disc swelling in Japanese patients

    Directory of Open Access Journals (Sweden)

    Iijima K

    2014-07-01

    Full Text Available Kei Iijima, Kimiya Shimizu, Yoshiaki Ichibe Department of Ophthalmology, Kitasato University, Kanagawa, Japan Purpose: To investigate the etiology of bilateral disc swelling in Japanese.Methods: Using Kitasato University’s Department of Neuro-Ophthalmology medical records and fundus photographs of the period December 1977 through November 2010, we retrospectively identified 121 outpatients who had been initially confirmed with bilateral disc swelling. Results: The most common cause of the bilateral disc swelling was increased intracranial pressure (ICP (59%; followed by pseudopapillitis (16%; uveitis (8%; hypertensive retinopathy (5%; bilateral optic neuritis, acute disseminated encephalomyelitis (ADEM and optic disc drusen (all at 2% each; and leukemia (1%. Unknown etiology accounted for 6% of the cases.Conclusion: Although increased ICP is the most common etiology for bilateral disc swelling, it can also be triggered by a variety of other causes. Pseudopapillitis is the most important progenitor of bilateral disc swelling in Japanese. Keywords: bilateral, disc swelling, papilledema, increased ICP, intracranial pressure

  7. Kinetics of swelling of polyelectrolyte gels: Fixed degree of ionization

    Science.gov (United States)

    Sen, Swati; Kundagrami, Arindam

    2015-12-01

    The swelling kinetics of uncharged and charged polymer (polyelectrolyte) gels in salt-free conditions is studied in one dimension by solving the constitutive equation of motion (Newton's law for the elementary gel volume) of the displacement variable by two theoretical methods: one in which the classical definition of stress is used with the bulk modulus taken as a parameter, and the other in which a phenomenological expression of the osmotic stress as a function of polymer density and degree of ionization is taken as an input to the dynamics. The time-evolution profiles for spatially varying polymer density and stress, along with the location of the gel-solvent interface, are obtained from the two methods. We show that both the polymer density (volume fraction) and stress inside the gel follow expected behaviours of being maximum for the uniformly shrunken gel, and relaxing slowly to the lowest values as the gel approaches equilibrium. We further show that, by comparing the temporal profiles of the gel-solvent interface and other variables between the two methods, one may attempt to assign an effective bulk modulus to the polyelectrolyte gel as a function of the degree of ionization and other parameters of the gel such as hydrophobicity, cross-link density, and the temperature. The major result we get is that the effective bulk modulus of a polyelectrolyte gel increases monotonically with its degree of ionization. In the process of identifying the parameters for a monotonic swelling, we calculated using a well-known expression of the free energy the equilibrium results of two-phase co-existence and the critical point of a polyelectrolyte gel with a fixed degree of ionization.

  8. A mathematical model of cellular swelling in Neuromyelitis optica.

    Science.gov (United States)

    Laranjeira, Simão; Symmonds, Mkael; Palace, Jacqueline; Payne, Stephen J; Orlowski, Piotr

    2017-11-21

    Neuromyelitis Optica (NMO) is a severe neuro-inflammatory disease of the central nervous system characterized by predominant damage to the optic nerve and of the spinal cord. The pathogenic antibody found in the majority of patients targets the AQP4 channels on astrocytic endfeet and causes the cells to swell. Although, the pathophysiology of the disease is broadly known, there are no specific targeted treatments for this process clinically available nor accurate prognostic markers both during attacks and for predicting long term neuronal damage. This lack is, in part, due to the rarity of the disease and its relatively recent pathogenic clarity. Hence, the ability to mathematically model the progress of the condition to test prospective therapies in silico would be a step forward. This paper combines state of the art models of cellular metabolism and cytotoxic oedema in neurons and astrocytes and augments it with a detailed characterization of water transport across the cellular membrane. In particular, we capture the process of perforation of the cell through the human complement cascade and resulting water and ionic fluxes. Simulating NMO by injecting its antibody and human complement into the extracellular space showed a 25% increase of the astrocytic volume after 12 h from onset. Most of the volume change occurred during the first 30 min of simulation with a peak volume change of 38%. The model was further adapted to simulate the therapeutic potential of CD59. It was found that there is a threshold of CD59 concentration that can prevent the swelling of astrocytes. Since the astrocyte volume changes mostly during the first hour, further experimental work should focus on this time scale to provide data for further model refinement and validation. Copyright © 2017. Published by Elsevier Ltd.

  9. Report on fundamental modeling of irradiation-induced swelling and creep in FeCrAl alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kohnert, Aaron A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dasgupta, Dwaipayan [Univ. of Tennessee, Knoxville, TN (United States); Wirth, Brian [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linton, Kory D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-23

    In order to improve the accident tolerance of light water reactor (LWR) fuel, alternative cladding materials have been proposed to replace zirconium (Zr)-based alloys. Of these materials, there is a particular focus on iron-chromium-aluminum (FeCrAl) alloys due to much slower oxidation kinetics in high-temperature steam than Zr-alloys. This should decrease the energy release due to oxidation and allow the cladding to remain integral longer in the presence of high temperature steam, making accident mitigation more likely. As a continuation of the development for these alloys, the material response must be demonstrated to provide suitable radiation stability, in order to ensure that there will not be significant dimensional changes (e.g., swelling), as well as quantifying the radiation hardening and radiation creep behavior. In this report, we describe the use of cluster dynamics modeling to evaluate the defect physics and damage accumulation behavior of FeCrAl alloys subjected to neutron irradiation, with a particular focus on irradiation-induced swelling and defect fluxes to dislocations that are required to model irradiation creep behavior.

  10. Relationship between swelling and the electrohydrodynamic properties of functionalized carboxymethyldextran macromolecules.

    Science.gov (United States)

    Rotureau, Elise; Thomas, Fabien; Duval, Jérôme F L

    2007-07-31

    The electrostatic, hydrodynamic, and swelling properties of a well-defined, functionalized carboxymethyldextran (CMD) polysaccharide are investigated in aqueous NaNO3 solution over a broad ionic strength range. The impact of the polycarboxylate charge and molar mass of the CMD macromolecules on their electrohydrodynamic features is thoroughly examined by combined protolytic titration, dynamic light scattering, and electrokinetic analyses. Electrophoretic mobility data obtained for sufficiently high electrolyte concentrations reveal a typical soft particle behavior. Upon decrease of the ionic strength, mobilities strongly increase in magnitude while significant electrostatic swelling takes place, as reflected in a decrease in the diffusion coefficients. CMD entities undergo conformational transitions from compact random coil at large ionic strengths to swollen coil and possibly a wormlike structure at lower NaNO3 concentrations. The magnitude of the variations in size and mobility with electrolyte concentration strongly depends on the overall charge of the CMD entity as well as on its molar mass. These factors control the stiffness of the constituent polymer chains and thus the degree of macromolecular permeability ("softness"). Using the soft-diffuse interface formalism previously developed for the electrohydrodynamics of charged permeable macromolecules, a quantitative analysis of the electrophoretic mobility data is presented. The measured values of the diffusion coefficient and space charge density Gamma degrees, as evaluated independently from the modeling of potentiometric titration curves, are taken into account in a self-consistent manner. It is found that large CMD entities of low charge densities are the most permeable to flow penetration with a limited heterogeneous electrostatic stiffening of the chains, whereas small CMD entities of larger Gamma degrees significantly expand upon lowering the ionic strength, giving rise to a strong anisotropy for the

  11. Biomass-Swelling Assisted Synthesis of Hierarchical Porous Carbon Fibers for Supercapacitor Electrodes.

    Science.gov (United States)

    Liu, Yang; Shi, Zijun; Gao, Yanfang; An, Weidan; Cao, Zhenzhu; Liu, Jinrong

    2016-10-26

    The preparation of porous materials from renewable energy sources is attracting intensive attention due to in terms of the application/economic advantage, and pore structural design is core in the development of efficient supercapacitors or available porous media. In this work, we focused on the transformation of natural biomass, such as cotton, into more stable porous carbonaceous forms for energy storage in practical applications. Biomorphic cotton fibers are pretreated under the effect of NaOH/urea swelling on cellulose and are subsequently used as a biomass carbon source to mold the porous microtubule structure through a certain degree of calcining. As a merit of its favorable structural features, the hierarchical porous carbon fibers exhibit an enhanced electric double layer capacitance (221.7 F g-1 at 0.3 A g-1) and excellent cycling stability (only 4.6% loss was observed after 6000 cycles at 2 A g-1). A detailed investigation displays that biomass-swelling behavior plays a significant role, not only in improving the surface chemical characteristics of biomorphic cotton fibers but also in facilitating the formation of a hierarchical porous carbon fiber structure. In contrast to traditional methods, nickel foams have been used as the collector for supercapacitor that requiring no additional polymeric binders or carbon black as support or conductive materials. Because of the absence of additive materials, we can further enhance capacitance. This remarkable capacitive performance can be due to sufficient void space within the porous microstructure. By effectively increasing the contact area between the carbon surface and the electrolyte, which can reduce the ion diffusion pathway or buffer the volume change during cycling. This approach opens a novel route to produce the abundantly different morphology of porous biomass-based carbon materials and proposes a green alternative method to meet sustainable development needs.

  12. Hydrogel swelling as a trigger to release biodegradable polymer microneedles in skin.

    Science.gov (United States)

    Kim, MinYoung; Jung, Bokyung; Park, Jung-Hwan

    2012-01-01

    Biodegradable polymeric microneedles were developed as a method for achieving sustained transdermal drug release. These microneedles have potential as a patient-friendly substitute for conventional sustained release methods. However, they have limitations related to the difficulty of achieving separation of the needles into the skin. We demonstrated that microneedle separation into the skin was mediated by hydrogel swelling in response to contact with body fluid after the needles were inserted into the skin. The hydrogel microparticles were synthesized by an emulsification method using poly-N-isopropylacrylamide (PNIPAAm). The microneedles were fabricated by micromolding poly-lactic-co-glycolic acid (PLGA) after filling the cavities of the mold with the hydrogel microparticles. The failure of microneedle tips caused by hydrogel swelling was studied in regard to contact with water, insertion of microneedles into porcine cadaver skin in vitro, stress-strain behavior, and insertion into the back skin of a hairless mouse in vivo. The drug delivery property of the hydrogel particles was investigated qualitatively by inserting polymer microneedles into porcine cadaver skin in vitro, and the sustained release property of PLGA microneedles containing hydrogel microparticles was studied quantitatively using the Franz cell model. The hydrogel particles absorbed water quickly, resulting in the cracking of the microneedles due to the difference in volume expansion between the needle matrix polymer and the hydrogel particles. The swollen particles caused the microneedles to totally breakdown, leaving the microneedle tips in the porcine cadaver skin in vitro and in the hairless mouse skin in vivo. Model drugs encapsulated in biodegradable polymer microneedles and hydrogel microparticles were successfully delivered by releasing microneedles into the skin. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. A SIPA-based theory of irradiation creep in the low swelling rate regime

    Energy Technology Data Exchange (ETDEWEB)

    Garner, F.A. [Pacific Northwest Lab., Richland, WA (United States); Woo, C.H. [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Nuclear Research Establishment

    1991-11-01

    A model is presented which describes the major facets of the relationships between irradiation creep, void swelling and applied stress. The increasing degree of anisotropy in distribution of dislocation Burger`s vectors with stress level plays a major role in this model. Although bcc metals are known to creep and swell at lower rates than fcc metals, it is predicted that the creep-swelling coupling coefficient is actually larger.

  14. A SIPA-based theory of irradiation creep in the low swelling rate regime

    Energy Technology Data Exchange (ETDEWEB)

    Garner, F.A. (Pacific Northwest Lab., Richland, WA (United States)); Woo, C.H. (Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Nuclear Research Establishment)

    1991-11-01

    A model is presented which describes the major facets of the relationships between irradiation creep, void swelling and applied stress. The increasing degree of anisotropy in distribution of dislocation Burger's vectors with stress level plays a major role in this model. Although bcc metals are known to creep and swell at lower rates than fcc metals, it is predicted that the creep-swelling coupling coefficient is actually larger.

  15. Modeling and Stress Analysis of Doubly-Fed Induction Generator during Grid Voltage Swell

    DEFF Research Database (Denmark)

    Zhou, Dao; Song, Yipeng; Blaabjerg, Frede

    2016-01-01

    the DFIG modeling and challenges when facing the symmetrical voltage swell. Then, the High Voltage Ride-Through (HVRT) capability of the DFIG can be calculated by using the demagnetizing current control, and the stator current, rotor current as well as the electromagnetic torque can be deduced during...... the transient voltage swell and its recovery. It is concluded that although both higher swell level and higher rotor speed cause higher rotor electromotive force, the doubly-fed induction generator can successfully ride through the grid fault due to the relatively small swell level required by the modern grid...

  16. A volatile tracer-assisted headspace analytical technique for determining the swelling capacity of superabsorbent polymers.

    Science.gov (United States)

    Zhang, Shu-Xin; Jiang, Ran; Chai, Xin-Sheng

    2017-09-01

    This paper reports on a new method for the determination of swelling capacity of superabsorbent polymers by a volatile tracer-assisted headspace gas chromatography (HS-GC). Toluene was used as a tracer and added to the solution for polymers swelling test. Based on the differences of the tracer partitioned between the vapor and hydrogel phase before and after the polymer's swelling capacity, a transition point (corresponding to the material swelling capacity) can be observed when plotting the GC signal of toluene vs. the ratio of solution added to polymers. The present method has good precision (RSDpolymers at the elevated temperatures. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Structural Changes in Lamellar Diblock Copolymer Thin Films upon Swelling in Nonselective Solvents

    DEFF Research Database (Denmark)

    Rudov, Andrey A.; Patyukova, Elena S.; Neratova, Irina V.

    2013-01-01

    swelling. This process is much faster and satisfies the space-filling condition at the thinning of the lamellae. That is why tilted lamellae are often observed in experiments and computer simulations. We demonstrate also that the distribution of the absorbed solvent in the film is inhomogeneous......Using dissipative particle dynamics simulations, we study the swelling of lamellae-forming diblock copolymer films in a nonselective solvent. Both the parallel and the perpendicular orientations of lamellae in the film are studied. The swelling of the film with parallel lamellae is accompanied...... with a maximum at the AB interfaces. The kinetics of the parallel lamellae swelling is compared with experimental data....

  18. The swelling of nitrile rubber by selected species in a synthetic jet turbine fuel

    Science.gov (United States)

    Graham, John Lynn

    The swelling of nitrile O-ring seals in petroleum distillate fuels has long been attributed to the aromatic species in these fuels. This presents a problem for synthetic fuels as they typically do not contain these aromatic species and thus may cause O-ring seals to shrink and fail. The composition of petroleum distillate fuels is extremely complex and it is not clear whether the swelling property originates from the aromatics in general, or if certain aromatics contribute more swelling character than others. Consequently, developing a general description of an efficient swelling promoter for O-rings in liquid hydrocarbon fuels will allow an unambiguous selection of candidate swelling agents for synthetic fuels. To accomplish this, a study was undertaken of the swelling of nitrile rubber (the most widely used O-ring material) in JP-5 (the jet propulsion fuel used by the U.S. Navy) and its synthetic equivalent S-5. Briefly, examining the molecular structure of nitrile rubber showed the fuel resistance of this polymer resides in the polar character of the cyano group suggesting that polar species in general, and hydrogen-bonded species in particular, should serve as efficient swelling promoters. A thorough test program utilizing a unique optical dilatometry method to provide temporal volume swell data, a GC-MS method for measuring the polymer/fuel partitioning, and a spectroscopic examination of thin nitrile rubber films confirmed this hypothesis. This program also showed that swelling character increases with decreasing molar volume which is consistent with previous work and general theories of solubility. Overall, this study showed that the most efficient aromatic swelling promoters for nitrile rubber are naphthalenes and asymmetrically substituted alkyl benzenes. However, polar species such as ketones and alcohols can be more efficient than aromatics while phenols and aromatic alcohols represent the most efficient potential swelling promoters for nitrile rubber in

  19. Can fertility signals lead to quality signals? Insights from the evolution of primate sexual swellings.

    Science.gov (United States)

    Huchard, Elise; Courtiol, Alexandre; Benavides, Julio A; Knapp, Leslie A; Raymond, Michel; Cowlishaw, Guy

    2009-05-22

    The sexual swellings of female primates have generated a great deal of interest in evolutionary biology. Two hypotheses recently proposed to elucidate their functional significance argue that maximal swelling size advertises either female fertility within a cycle or female quality across cycles. Published evidence favours the first hypothesis, and further indicates that larger swellings advertise higher fertility between cycles. If so, a male preference for large swellings might evolve, driving females to use swellings as quality indicators, as proposed by the second hypothesis. In this paper, we explore this possibility using a combination of empirical field data and mathematical modelling. We first test and find support for three key predictions of the female-quality hypothesis in wild chacma baboons (Papio ursinus): (i) inter-individual differences in swelling size are maintained across consecutive cycles, (ii) females in better condition have larger swellings and higher reproductive success, and (iii) males preferentially choose females with large swellings. We then develop an individual-based simulation model that indicates that females producing larger swellings can achieve higher mating success even when female-female competition is low and within-female variance in the trait is high. Taken together, our findings show that once sexual swellings have evolved as fertility signals, they might, in certain socio-sexual systems, be further selected to act as quality signals. These results, by reconciling two hypotheses, help to clarify the processes underlying sexual swelling evolution. More generally, our findings suggest that mate choice for direct benefits (fertility) can lead to indirect benefits (good genes).

  20. French Polynesia Hotspot Swells Explained By Dynamic Topography

    Science.gov (United States)

    Adam, C.; Yoshida, M.; Isse, T.; Suetsugu, D.; Shiobara, H.; Sugioka, H.; Kanazawa, T.; Fukao, Y.; Barruol, G.

    2007-12-01

    Situated on the South Pacific Superswell, French Polynesia is a region characterized by numerous geophysical anomalies among which a high volcanism concentration. Seven hotspots are required to explain the observed chains, volcanism ages and geochemical trends. Many open questions still remain on the origin of these hotspot chains: are they created by passive uplift of magma due to discontinuities in the structure of the lithosphere or by the ascent of mantle plumes? In this case, at which depth do these plumes initiate in the mantle? Many geophysical observations (bathymetry, gravity, magnetism, volcanism ages..) are used to understand the unique phenomenon occurring on this region. The most useful information may come from tomography models since they provide a 3D view of the mantle. Until recently, the tomography models over the region were quite inaccurate because of the sparse location of the seismic stations. The deployment of two new seismic stations networks (BBOBS and temporary island stations) has lately remedied this failing. The resulting tomography model obtained through the inversion of Rayleigh waves provides the most accurate view of the shallowest part of the mantle (depths ≤ 240 km) beneath French Polynesia. Indeed, for the first time the accuracy of a tomography model is good enough to provide information about plume phenomenology in this complex region. In order to quantify the plumes effect on the seafloor, we compute the dynamic topography through an instantaneous flow model. The general trend of the observed depths anomalies (highs and lows) is well recovered. For example the amplitude, location and extension of the swells associated with the Society, Macdonald and Rarotonga are accurately described by the dynamic model. We also find that dynamic uplift is associated with the Tuamotu archipelago which means that a part of the observed swell is due to the present day action of plumes. Since no volcanism ages are available over this chain

  1. CO 2 Capture Capacity and Swelling Measurements of Liquid-like Nanoparticle Organic Hybrid Materials via Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy

    KAUST Repository

    Park, Youngjune

    2012-01-12

    Novel nanoparticle organic hybrid materials (NOHMs), which are comprised of organic oligomers or polymers tethered to an inorganic nanosized cores of various sizes, have been synthesized, and their solvating property for CO 2 was investigated using attenuated total reflectance (ATR) Fourier transform infrared (FT-IR) spectroscopy. Simultaneous measurements of CO 2 capture capacity and swelling behaviors of polyetheramine (Jeffamine M-2070) and its corresponding NOHMs (NOHM-I-PE2070) were reported at temperatures of (298, 308, 323 and 353) K and CO 2 pressure conditions ranging from (0 to 5.5) MPa. The polymeric canopy, or polymer bound to the nanoparticle surface, showed significantly less swelling behavior with enhanced or comparable CO 2 capture capacity compared to pure unbound polyetheramine. © 2011 American Chemical Society.

  2. Properties and toughening mechanisms of PVA/PAM double-network hydrogels prepared by freeze-thawing and anneal-swelling.

    Science.gov (United States)

    Ou, Kangkang; Dong, Xia; Qin, Chengling; Ji, Xinan; He, Jinxin

    2017-08-01

    It is well known that preparation method of hydrogels has a significant effect on their properties. In this paper, freeze-thawing and anneal-swelling were applied to prepare poly(vinyl alcohol)/polyacrylamide (PVA/PAM) double-network hydrogels with covalently and physically cross-linked networks. The properties of these hydrogels were investigated and compared to control hydrogels. Results indicated that hydrogels fabricated by freeze-thawing show larger pores size and higher swelling capacity than those made by anneal-swelling and control hydrogels. Hydrogels prepared by anneal-swelling exhibit higher mechanical strength, energy dissipation, fracture energy, gel fraction and crystallinity than those made by freeze-thawing and control hydrogels. Physical cross-linking plays a key role in formation of physical-chemical double-network. The toughening mechanism of double-network hydrogel is related to their chain-fracture behavior and elasticity. The results also indicated that appropriate methods can endow hydrogels with specific microstructures and properties which would broaden current hydrogels research and applications in biomedical fields. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Impacts of burnup-dependent swelling of metallic fuel on the performance of a compact breed-and-burn fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hartanto, Donny; Heo, Woong; Kim, Chi Hyung; Kim, Yong Hee [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of)

    2016-04-15

    The U-Zr or U-TRU-Zr cylindrical metallic fuel slug used in fast reactors is known to swell significantly and to grow during irradiation. In neutronics simulations of metallic-fueled fast reactors, it is assumed that the slug has swollen and contacted cladding, and the bonding sodium has been removed from the fuel region. In this research, a realistic burnup-dependent fuel-swelling simulation was performed using Monte Carlo code McCARD for a single-batch compact sodium-cooled breed-and-burn reactor by considering the fuel-swelling behavior reported from the irradiation test results in EBR-II. The impacts of the realistic burnup-dependent fuel swelling are identified in terms of the reactor neutronics performance, such as core lifetime, conversion ratio, axial power distribution, and local burnup distributions. It was found that axial fuel growth significantly deteriorated the neutron economy of a breed-and-burn reactor and consequently impaired its neutronics performance. The bonding sodium also impaired neutron economy, because it stayed longer in the blanket region until the fuel slug reached 2% burnup.

  4. Swelling characterization and drug delivery kinetics of polyacrylamide-co-itaconic acid/chitosan hydrogels

    Directory of Open Access Journals (Sweden)

    2009-01-01

    Full Text Available Hybrid polymeric networks composed of polyacrylamide and chitosan were developed to determine their swelling and ascorbic acid delivery kinetics at various chitosan concentrations. The hybrid acrylamide/chitosan hydrogels were synthesized in aqueous itaconic acid solution (1% w/w. Young’s modulus was also evaluated for the hydrogels, and the results were correlated with the swelling properties. Swelling experiments were carried out using three different pH solutions: acidic (pH 4 buffer solution, neutral (distilled water and basic (pH 10 buffer solution. The results of the swelling study showed that the swelling properties of the network varied with the changes of the pH in the swelling solution, as well as concentration of chitosan. When chitosan concentration increased, the swelling capacity diminished, and therefore Young’s modulus increased. The results indicated that the swelling process followed a second order kinetics. The ascorbic acid diffusion inside the hydrogel follows a Fickian mechanism. The ascorbic acid diffusion coefficients are reported as a function of chitosan concentration.

  5. The Swell knowledge work dataset for stress and user modeling research

    NARCIS (Netherlands)

    Koldijk, S.J.; Sappelli, M.; Verberne, S.; Neerincx, M.A.; Kraaij, W.

    2014-01-01

    This paper describes the new multimodal SWELL knowl- edge work (SWELL-KW) dataset for research on stress and user modeling. The dataset was collected in an experiment, in which 25 people performed typical knowledge work (writing reports, making presentations, reading e-mail, searching for

  6. A rare cause of calf swelling: the Morel-Lavallee lesion.

    LENUS (Irish Health Repository)

    Moriarty, J M

    2011-03-01

    Calf swelling is a common clinical presentation with a wide and varied differential diagnosis. The Morel-Lavallee is a rare cause of subcutaneous swelling, caused by post-traumatic shearing of the hypodermis from the underlying fascia. The potential space so created fills with blood, lymph and necrotic fat giving specific findings on MR evaluation.

  7. Evolution of swelling pressure of cohesive-frictional, rough and elasto-plastic granulates

    NARCIS (Netherlands)

    Luding, Stefan; Bauer, Erich; Jiang, M.J.; Liu, F.; Bolton, M.

    2010-01-01

    The subject of this study is the modeling of the evolution of the swell-ing pressure of granulates with cohesive-frictional, rough and elasto-plastic “mi-croscopic” contact properties. The spherical particles are randomly arranged in a periodic cubic space with a fixed volume so that an increase of

  8. Effects of swelling forces on the durability of wood adhesive bonds

    Science.gov (United States)

    Blake M. Hofferber; Edward Kolodka; Rishawn Brandon; Robert J. Moon; Charles R. Frihart

    2006-01-01

    The purpose of this study was to investigate the role of wood swelling on performance of wood-adhesive bonds (resorcinol formaldehyde, epoxy, emulsion polymerisocyanate), for untreated and acetylated wood. Effects of these treatments on measured strain anisotropy and swelling stress were measured and then related to compressive shear strength and percentage wood...

  9. Swelling behaviour of isora/natural rubber composites in oils used in ...

    Indian Academy of Sciences (India)

    Unknown

    adhesion. Fibres, if bonded effectively are supposed to restrict the swelling of elastomers. The adhesion between rubber and various synthetic fibres like glass, asbestos, and natural fibres like sisal, oil palm etc have been studied using restricted swelling measurements (Das 1973; Varghese et al. 1995; Prasanth Kumar and ...

  10. Modelling of fission gas swelling in the high burnup UO{sub 2} fuel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Ho; Lee, Chan Bock; Bang, Je Gun; Jung, Yeon Ho

    1999-06-01

    Discharge burnup of the fuel in LWR has been increased to improve the fuel economy, and currently the high burnup fuel of over 70 MWd/kg U-rod avg. is being developed by the fuel vendors worldwide. At high burnup, thermal / mechanical properties of the fuel is known to change and new phenomenon could arise. This report describes the model development on fission gas swelling in high burnup UO{sub 2} fuel. For the low burnup fuel, swelling only by the solid fission products has been considered in the fuel performance analysis. However, at high burnup fuel, swelling by fission gas bubbles can not be neglected anymore. Therefore, fission gas swelling model which can predictbubble swelling of the high burnup UO{sub 2} fuel during the steady-state and the transient conditions in LWR was developed. Based on the bubble growth model, the empirical fission gas swelling model was developed as function of burnup, time and temperature. The model showed that fuel bubble swelling would be proportional to the burnup by the power of 1.157 and to the time by the power of 0.157. Comparison of the model prediction with the measured fission gas swelling data under the various burnup and temperature conditions showed that the model would predict the measured data reasonably well. (author). 20 refs., 8 tabs., 17 figs.

  11. Effects of particle size and heating rate on swelling characteristics of a bituminous coal

    Energy Technology Data Exchange (ETDEWEB)

    Yu, D.; Xu, M.; Liu, X.; Wang, Q.; Gao, X. [Huazhong University of Science and Technology, Wuhan (China)

    2006-02-15

    A size-classified bituminous coal was pyrolyzed in a laboratory drop tube furnace at different heating rates. The effects of coal particle size and heating rate on particle swelling properties were investigated. The results show that coal particles undergo obvious swelling during pyrolysis, leading to the formation of a large number of char cenospheres with a large central void surrounded by a thin shell. Analyses indicate this is caused by high concentrations of vitrinite present in coal samples. At the same heating rate, the extent of swelling increases with deceasing particle size and the difference in swelling decreases with increasing particle size. Since finer coal samples contain higher content of vitrinite, the observed phenomena are considered to be the result of the different content of vitrinite in these samples. The reason is that coal particles containing more vitrinite early undergo a softening and deformation stage and swell significantly during pyrolysis. When the heating rate increases the swelling of coal particle sin the same size range firstly increases and then decreases, which implies that an optimum heating rate at which coal particles swell most must exist. Reasonable explanation for this effect of heating rate on particle swelling are provided in the present study. 14 refs., 4 figs., 2 tabs.

  12. Green tea polyphenols attenuate glial swelling and mitochondrial dysfunction following oxygen-glucose deprivation in cultures

    Science.gov (United States)

    Astrocyte swelling is a major component of cytotoxic brain edema in ischemia. Oxidative stress and mitochondrial dysfunction have been hypothesized to contribute to such swelling in cultures. We investigated the protective effects of polyphenol-rich green tea extract (GTE) on key features of ischemi...

  13. Swelling behaviour of isora/natural rubber composites in oils used in ...

    Indian Academy of Sciences (India)

    The solvent swelling characteristics of natural rubber composites containing both untreated and alkali treated fibres were investigated in aromatic and aliphatic solvents like toluene, and -hexane. The diffusion experiments were conducted by the sorption gravimetric method. The restrictions on elastomer swelling exerted ...

  14. An Approach to Swelling Potential of Cohesive Soils: Avcilar-Esenyurt Example

    Directory of Open Access Journals (Sweden)

    Erkan Bozkurtoğlu

    2015-12-01

    Full Text Available Cohesive soil exhibits various degrees of swelling potential due to their clay contents and minerals. Many studies have been conducted to determine the degree of swelling of cohesive soil in the literature. These studies are related with the percentage of clay and colloid, plasticity index, shrinkage limit, activity, liquid limit, the water content and absorption and some of them give tables and others give graphics. In this study, the swelling potential of cohesive soil depending on liquid limit and natural water content were investigated. The graphical relation in literature was solved and a general equation between the water content and liquid limit of cohesive soil was determined for predicting swelling percentage. It is understood that the relation of swelling percentage between water content and liquid limit is not logarithmic as given in the literature, but it is an exponential equation with a -0.187w power constant N. The proposed methodology was applied to cohesive soil between Avcılar and Esenyurt. In literature classifications for swelling potential are variable and these definitions are inconsistent with each other. Whereas reliable numerical values for swelling are obtained by the proposed approach of swelling potential associated with clays water content.

  15. Cell swelling activates separate taurine and chloride channels in Ehrlich mouse ascites tumor cells

    DEFF Research Database (Denmark)

    Lambert, Ian Henry; Hoffmann, Else Kay

    1994-01-01

    The taurine efflux from Ehrlich ascites tumor cells is stimulated by hypotonic cell swelling. The swelling-activated taurine efflux is unaffected by substitution of gluconate for extracellular Cl– but inhibited by addition of MK196 (anion channel blocker) and 4,4 -diisothiocyanostilbene-2...

  16. Loss of knee-extension strength is related to knee swelling after total knee arthroplasty

    DEFF Research Database (Denmark)

    Holm, Bente; Kristensen, Morten T; Bencke, Jesper

    2010-01-01

    To examine whether changes in knee-extension strength and functional performance are related to knee swelling after total knee arthroplasty (TKA).......To examine whether changes in knee-extension strength and functional performance are related to knee swelling after total knee arthroplasty (TKA)....

  17. The swelling of clays and its effects on underground storage works; Le Gonflement des argiles et ses effets sur les ouvrages souterrains de stockage

    Energy Technology Data Exchange (ETDEWEB)

    Gaombalet, J

    2004-03-15

    The aim of this work is to study the swelling of clays and more generally the clayey media in relation to storage. Different types of clays, natural or reworked, have been studied in a rheological point of view, with the aim to result in behavior laws allowing to reproduce some identified phenomena. The first part of this work is a presentation of the concept of geological underground storage. The second part deals with clays. They are studied at a microscopic level and their macroscopic behavior are presented too. In the third part, the equations of the couplings: mechanics/transport in the porous media in general and applied to clays are formulated. Three types of clays have particularly been studied: a stiff clay, a plastic clay and a reworked clay. The following part deals with the swelling of clays. The analysis carried out through a bibliographical study has led us to propose a behavior law for the swelling-retirement. This part concerns essentially the mechanics. The behavior model, which integrates the swelling, involves the concentration of the ions present in solution in the interstitial water. Concerning the transport, of water or ions, the research of coherent models have led us to revise some models described in the second part and concerning the transport of solutions in porous media. The last part concerns the computerized simulation. It begins by a brief description of the computer code. We show how the equations described in the work are dealt with in the computer code. At last, some storage applications (computerized simulation) are given. (O.M.)

  18. Predicting extended wear complications from overnight corneal swelling.

    Science.gov (United States)

    Graham, A D; Fusaro, R E; Polse, K A; Lin, M C; Giasson, C J

    2001-12-01

    To examine the hypothesis that the corneal overnight swelling response (ONSR) is a predictor of ocular complications in contact lens extended wear (EW). The Berkeley Contact Lens Extended Wear Study (CLEWS) was a randomized, concurrently controlled clinical trial in which more than 200 subjects in EW with rigid gas-permeable (RGP) lenses were observed for 1 year. After adapting to EW, subjects were randomized to either medium or high oxygen-permeable (Dk) RGP lenses and underwent clinical assessments, keratometry, and corneal pachometry at 3-month intervals. The ONSR was directly related to lens Dk (P = 0.01) and exhibited substantial variability across subjects. The probability of remaining free of complications over time was not significantly lower for subjects with a mild ONSR compared with those with greater edema (P = 0.84). The risk of development of keratopathy was not significantly related to the ONSR (relative risk = 1.00). The corneal ONSR is not a good predictor of ocular complications in 1 year of RGP EW. Lenses that cause little or no corneal edema are not necessarily safer for overnight wear.

  19. Experimental Analysis on Shrinkage and Swelling in Ordinary Concrete

    Directory of Open Access Journals (Sweden)

    Barbara Kucharczyková

    2017-01-01

    Full Text Available The paper deals with the experimental determination of shrinkage development during concrete ageing. Three concrete mixtures were made. They differed in the amount of cement in the fresh mixture, 300, 350, and 400 kg/m3. In order to determine the influence of plasticiser on the progress of volume changes, another three concrete mixtures were prepared with plasticiser in the amount of 0.25% by cement mass. Measurements were performed with the goal of observing the influence of cement and plasticiser content on the overall development of volume changes in the concrete. Changes in length and mass losses of the concrete during ageing were measured simultaneously. The continuous measurement of concrete mass losses caused by drying of the specimen’s surface proved useful during the interpretation of results obtained from the concrete shrinkage measurement. During the first 24 hours of ageing, all the concrete mixtures exhibited swelling. Its magnitude and progress were influenced by cement, water, and plasticiser content. However, a loss of mass caused by water evaporation from the surface of the specimens was also recorded in this stage. The measured progress of shrinkage corresponded well to the progress of mass loss.

  20. Surgical sealants with tunable swelling, burst pressures, and biodegradation rates.

    Science.gov (United States)

    Henise, Jeff; Hearn, Brian R; Santi, Daniel V; Kamata, Hiroyuki; Sakai, Takamasa; Ashley, Gary W

    2017-08-01

    We developed two types of polyethylene glycol (PEG)-based surgical sealants, which we have termed the PER and PRO series. In one, the PRO series, an 8-arm PEG containing activated carbonyl end-groups was reacted with a 4-armed amino-PEG. In the second, the PER series, a 4-arm PEG containing bi-functional end groups with four azides and four activated esters was reacted by strain-promoted alkyne-azide cycloaddition with a 4-arm cyclooctyne-PEG to give a near-ideal Tetra-PEG hydrogel. The sealants showed predictably tunable strength, swelling, adhesion, and gelation properties. The gels were compared to commercially available PEG-based sealants and exhibit physical properties equivalent to or better than the standards. Variants of each gel-format were prepared that contained a β-eliminative cleavable linker in the crosslinks to control degradation rate. Linkers of this type self-cleave with half-lives spanning from hours to years, and offer the unique ability to precisely tune the degradation to match the healing process. In addition, these linkers could serve as cleavable tethers for controlled drug release. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1602-1611, 2017. © 2016 Wiley Periodicals, Inc.

  1. Internal structure and swelling behaviour of in silico microgel particles

    Science.gov (United States)

    Rovigatti, Lorenzo; Gnan, Nicoletta; Zaccarelli, Emanuela

    2018-01-01

    Microgels are soft colloids that, by virtue of their polymeric nature, can react to external stimuli such as temperature or pH by changing their size. The resulting swelling/deswelling transition can be exploited in fundamental research as well as for many diverse practical applications, ranging from art restoration to medicine. Such an extraordinary versatility stems from the complex internal structure of the individual microgels, each of which is a crosslinked polymer network. Here we employ a recently-introduced computational method to generate realistic microgel configurations and look at their structural properties, both in real and Fourier space, for several temperatures across the volume phase transition as a function of the crosslinker concentration and of the confining radius employed during the ‘in-silico’ synthesis. We find that the chain-length distribution of the resulting networks can be analytically predicted by a simple theoretical argument. In addition, we find that our results are well-fitted to the fuzzy-sphere model, which correctly reproduces the density profile of the microgels under study.

  2. Brain Cell Swelling During Hypocapnia Increases with Hyperglycemia or Ketosis

    Science.gov (United States)

    Glaser, Nicole; Bundros, Angeliki; Anderson, Steve; Tancredi, Daniel; Lo, Weei; Orgain, Myra; O'Donnell, Martha

    2014-01-01

    Severe hypocapnia increases the risk of DKA-related cerebral injury in children, but the reason for this association is unclear. To determine whether the effects of hypocapnia on the brain are altered during hyperglycemia or ketosis, we induced hypocapnia (pCO2 20 ± 3 mmHg) via mechanical ventilation in three groups of juvenile rats: 25 controls, 22 hyperglycemic rats (serum glucose 451± 78 mg/dL) and 15 ketotic rats (beta-hydroxy butyrate 3.0 ± 1.0 mmol/L). We used magnetic resonance imaging to measure cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) values in these groups and in 17 ventilated rats with normal pCO2 (40±3 mmHg). In a subset (n=35), after 2 hrs of hypocapnia, pCO2 levels were normalized (40±3 mmHg) and ADC and CBF measurements repeated. Declines in CBF with hypocapnia occurred in all groups. Normalization of pCO2 after hypocapnia resulted in striatal hyperemia. These effects were not substantially altered by hyperglycemia or ketosis, however, declines in ADC during hypocapnia were greater during both hyperglycemia and ketosis. We conclude that brain cell swelling associated with hypocapnia is increased by both hyperglycemia and ketosis, suggesting that these metabolic conditions may make the brain more vulnerable to injury during hypocapnia. PMID:24443981

  3. Specific Effects of Fiber Size and Fiber Swelling on Biomass Substrate Surface Area and Enzymatic Digestibility

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Xiaohui; Grego, Courtnee; Zhang, Xiao

    2013-09-01

    To clarify the specific effect of biomass substrate surface area on its enzymatic digestibility, factors of fiber size reduction and swelling changes were investigated by using poplar substrates with controlled morphological and chemical properties after modified chemical pulping. Results showed that fiber size changes had insignificant influence on enzymatic hydrolysis, although the external surface area increased up to 41% with the reduction of fiber size. Swelling changes caused by increased biomass fiber porosities after PFI refining showed a significant influence on the efficiency of enzymatic hydrolysis. It is also found that chemical properties such as xylan and lignin content can influence the swelling effect. Xylan is confirmed to facilitate substrate hydrolysability by swelling, while lignin restricts swelling effect and thus minimizes the enzyme accessibility to substrates.

  4. Efficacy of ultrasonography in the diagnosis of inflammatory swellings of odontogenic origin

    Directory of Open Access Journals (Sweden)

    Jai Sanghar

    2012-01-01

    Full Text Available Objective: The purpose of this study was to evaluate the efficacy of ultrasound in the diagnosis of inflammatory swellings of odontogenic origin. Study design: The study group consisted of 25 patients with inflammatory swellings of odontogenic origin. Only patients with unilateral swellings were considered for inclusion in the pathologic study group and normal contralateral side was taken as control. Results: Clinically, four cases were diagnosed as cellulitis and 21 cases as abscesses. Under ultrasonography (USG diagnosis, six cases were diagnosed as edema and two cases as cellulitis and 15 cases as preabscess and two cases as abscesses, considering the intra operative diagnosis as the gold standard technique. The ultrasonography technique presented sensitivity of 92%. Conclusion: USG can differentiate facial edema, facial cellulitis, and dentoalveolar abscess. USG can also evaluate the extension of these swellings. It is prudent to subject patients with inflammatory swellings of the maxillofacial region to USG in order to determine the appropriate treatment plan.

  5. Numerical Modelling of Insulin and Amyloglucosidase Release from Swelling Ca-Alginate Beads

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Snabe, T.; Pedersen, Lars Haastrup

    2003-01-01

    The release of insulin hexamer (39 kD) and amyloglucosidase (AMG, 97 kD), entrapped in spherical Ca–alginate beads, was investigated. While the release of insulin could be described solely by diffusion this was not the case for the 1.6 (r m /r m) larger AMG protein, where rm is the Stokes......–Einstein effective molecular radius. Because the alginate bead size was not constant during the release experiments, it was hypothesised that in addition to the diffusional mass transfer, a non-negligible convective flow of liquid in or out of the beads was present due to swelling or shrinkage, respectively...... convective flow in the numerical model, release could be described more accurately. The numerical model was able to describe the release  characteristics from both shrinking, swelling, and non-swelling alginate beads. To evaluate the effect of bead swelling on the protein release rate, a swelling modulus...

  6. Cell swelling and ion redistribution assessed with intrinsic optical signals

    Directory of Open Access Journals (Sweden)

    WITTE OTTO W.

    2001-01-01

    Full Text Available Cell volume changes are associated with alterations of intrinsic optical signals (IOS. In submerged brain slices in vitro, afferent stimulation induces an increase in light transmission. As assessed by measurement of the largely membrane impermeant ion tetramethylammonium (TMA in the extracellular space, these IOS correlate with the extent and time course of the change of the extracellular space size. They have a high signal to noise ratio and allow measurements of IOS changes in the order of a few percent. Under conditions of reduced net KCl uptake (low Cl solution a directed spatial buffer mechanism (K syphoning can be demonstrated in the neocortex with widening of the extracellular space in superficial layers associated with a reduced light transmission and an increase of extracellular K concentration. The nature of the IOS under pathophysiological conditions is less clear. Spreading depressions first cause an increase of light transmission, then a decrease. Such a decrease has also been observed following application of NMDA where it was associated with structural damage. Pharmacological analyses suggest that under physiological conditions changes of extracellular space size are mainly caused by astrocytic volume changes while with strong stimuli and under pathophysiological conditions also neuronal swelling occurs. With reflected light usually signals opposite to those observed with transmitted light are seen. Recording of IOS from interface slices gives very complex signals since under these conditions an increase of light transmission has been reported to be superimposed by a decrease of the signal due to mechanical lensing effects of the slice surface. Depending on the method of measurement and the exact conditions, several mechanisms may contribute to IOS. Under well defined conditions IOS are a useful supplementary tool to monitor changes of extracellular volume both in space and time.

  7. Heat-to-heat variability of irradiation creep and swelling of HT9 irradiated to high neutron fluence at 400-600{degrees}C

    Energy Technology Data Exchange (ETDEWEB)

    Toloczko, M.B.; Garner, F.A. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-10-01

    Irradiation creep data on ferritic/martensitic steels are difficult and expensive to obtain, and are not available for fusion-relevant neutron spectra and displacement rates. Therefore, an extensive creep data rescue and analysis effort is in progress to characterize irradiation creep of ferritic/martensitic alloys in other reactors and to develop a methodology for applying it to fusion applications. In the current study, four tube sets constructed from three nominally similar heats of HT9 subjected to one of two heat treatments were constructed as helium-pressurized creep tubes and irradiated in FFTF-MOTA at four temperatures between 400 and 600{degrees}C. Each of the four heats exhibited a different stress-free swelling behavior at 400{degrees}C, with the creep rate following the swelling according to the familiar B{sub o} + DS creep law. No stress-free swelling was observed at the other three irradiation temperatures. Using a stress exponent of n = 1.0 as the defining criterion, {open_quotes}classic{close_quotes} irradiation creep was found at all temperatures, but, only over limited stress ranges that decreased with increasing temperature. The creep coefficient B{sub o} is a little lower ({approx}50%) than that observed for austenitic steel, but the swelling-creep coupling coefficient D is comparable to that of austenitic steels. Primary transient creep behavior was also observed at all temperatures except 400{degrees}C, and thermal creep behavior was found to dominate the deformation at high stress levels at 550 and 600{degrees}C.

  8. Orientation-dependent interfacial mobility governs the anisotropic swelling in lithiated silicon nanowires.

    Science.gov (United States)

    Yang, Hui; Huang, Shan; Huang, Xu; Fan, Feifei; Liang, Wentao; Liu, Xiao Hua; Chen, Long-Qing; Huang, Jian Yu; Li, Ju; Zhu, Ting; Zhang, Sulin

    2012-04-11

    Recent independent experiments demonstrated that the lithiation-induced volume expansion in silicon nanowires, nanopillars, and microslabs is highly anisotropic, with predominant expansion along the direction but negligibly small expansion along the direction. The origin of such anisotropic behavior remains elusive. Here, we develop a chemomechanical model to study the phase evolution and morphological changes in lithiated silicon nanowires. The model couples the diffusive reaction of lithium with the lithiation-induced elasto-plastic deformation. We show that the apparent anisotropic swelling is critically controlled by the orientation-dependent mobility of the core-shell interface, i.e., the lithiation reaction rate at the atomically sharp phase boundary between the crystalline core and the amorphous shell. Our results also underscore the importance of structural relaxation by plastic flow behind the moving phase boundary, which is essential to quantitative prediction of the experimentally observed morphologies of lithiated silicon nanowires. The study sheds light on the lithiation-mediated failure in nanowire-based electrodes, and the modeling framework provides a basis for simulating the morphological evolution, stress generation, and fracture in high-capacity electrodes for the next-generation lithium-ion batteries. © 2012 American Chemical Society

  9. Kinetic modeling for macromolecule loading into crosslinked polyacrylamide hydrogel matrix by swelling.

    Science.gov (United States)

    Chen, L L

    1998-05-01

    A kinetic model was proposed to characterize the swelling phenomenon of polyacrylamide hydrogel and to quantify and predict the loading of insulin into the hydrogel by swelling. Polyacrylamide hydrogel and porcine insulin were used in the study. During swelling, the insulin concentration in the hydrogel was found to be higher than that in the loading solution, which could be attributed to ionization of the ionic networks, Donnan exclusion, and the possible ionic interactions between the anionic carboxylic pendants and cationic insulin. The experimental results demonstrated that the proposed kinetic model was able to describe the swelling kinetics of polyacrylamide hydrogel and the loading kinetics of insulin by using only two constants [input rate (Kin) and output rate (Kout)]. The experimental values of Kin and Kout were found to highly depend on the concentration of HCl. As medium pH declined (because of the addition of HCl), the degree of swelling decreased and the insulin loading amount in the hydrogel was reduced. A linear log-log function was observed between Kin and the volume fraction of HCl. The Kout values also decreased with the addition of HCl, but remained constant after more than 1% (v/v) of HCl (0.01 N) was added. The proposed model was able to characterize the swelling kinetics of polyacrylamide and predict the loading dose of insulin in the polyacrylamide hydrogel by swelling.

  10. Deformation mechanisms in a coal mine roadway in extremely swelling soft rock.

    Science.gov (United States)

    Li, Qinghai; Shi, Weiping; Yang, Renshu

    2016-01-01

    The problem of roadway support in swelling soft rock was one of the challenging problems during mining. For most geological conditions, combinations of two or more supporting approaches could meet the requirements of most roadways; however, in extremely swelling soft rock, combined approaches even could not control large deformations. The purpose of this work was to probe the roadway deformation mechanisms in extremely swelling soft rock. Based on the main return air-way in a coal mine, deformation monitoring and geomechanical analysis were conducted, as well as plastic zone mechanical model was analysed. Results indicated that this soft rock was potentially very swelling. When the ground stress acted alone, the support strength needed in situ was not too large and combined supporting approaches could meet this requirement; however, when this potential released, the roadway would undergo permanent deformation. When the loose zone reached 3 m within surrounding rock, remote stress p ∞ and supporting stress P presented a linear relationship. Namely, the greater the swelling stress, the more difficult it would be in roadway supporting. So in this extremely swelling soft rock, a better way to control roadway deformation was to control the releasing of surrounding rock's swelling potential.

  11. Paternal care and the evolution of exaggerated sexual swellings in primates.

    Science.gov (United States)

    Alberts, Susan C; Fitzpatrick, Courtney L

    2012-07-01

    The exaggerated sexual swellings exhibited by females of some primate species have been of interest to evolutionary biologists since the time of Darwin. We summarize existing hypotheses for their function and evolution and categorize these hypotheses within the context of 3 types of variation in sexual swelling size: 1) variation within a single sexual cycle, 2) variation between the sexual cycles of a single female, and 3) differences between females. We then propose the Paternal Care Hypothesis for the function of sexual swellings, which posits that exaggerated sexual swellings function to elicit the right quantity and quality of male care for a female's infant. As others have noted, swellings may allow females to engender paternity confusion, or they may allow females to confer relative paternal certainty on one male. Key to our hypothesis is that both of these scenarios create an incentive for one or more males to provide care. This hypothesis builds on previous hypotheses but differs from them by highlighting the elicitation of paternal care as a key function of swellings. Our hypothesis predicts that true paternal care (in which males accurately differentiate and provide assistance to their own offspring) will be most common in species in which exaggerated swellings accurately signal the probability of conception, and males can monopolize females during the window of highest conception probability. Our hypothesis also predicts that females will experience selection to behave in ways that either augment paternity confusion or enhance paternal certainty depending on their social and demographic contexts.

  12. Episodic swell growth inferred from variable uplift of the Cape Verde hotspot islands

    Science.gov (United States)

    Ramalho, R.; Helffrich, G.; Cosca, M.; Vance, D.; Hoffmann, D.; Schmidt, D.N.

    2010-01-01

    On the Beagle voyage, Charles Darwin first noted the creation and subsidence of ocean islands, establishing in geology's infancy that island freeboard changes with time. Hotspot ocean islands have an obvious mechanism for freeboard change through the growth of the bathymetric anomaly, or swell, on which the islands rest. Models for swell development indicate that flexural, thermal or dynamic pressure contributions, as well as spreading of melt residue from the hotspot, can all contribute to island uplift. Here we test various models for swell development using the uplift histories for the islands of the Cape Verde hotspot, derived from isotopic dating of marine terraces and subaerial to submarine lava-flow morphologies. The island uplift histories, in conjunction with inter-island spacing, uplift rate and timing differences, rule out flexural, thermal or dynamic pressure contributions. We also find that uplift cannot be reconciled with models that advocate the spreading of melt residue in swell development unless swell growth is episodic. Instead, we infer from the uplift histories that two processes have acted to raise the islands during the past 6 Myr. During an initial phase, mantle processes acted to build the swell. Subsequently, magmatic intrusions at the island edifice caused 350 m of local uplift at the scale of individual islands. Finally, swell-wide uplift contributed a further 100 m of surface rise.

  13. Co-existence of wind seas and swells along the west coast of India during non-monsoon season

    Digital Repository Service at National Institute of Oceanography (India)

    Rashmi, R.; Aboobacker, V.M.; Vethamony, P.; John, M.P.

    . Sea Swell Energy Ratio quantifies wind sea, swell and mixed seas prevailing in these regions during non-monsoon season. Intermodal distance (ID) between the energy peaks is moderately separated during non-monsoon season, whereas, during the shamal...

  14. Swelling characteristics and drug release kinetics of Ag/PVA hydrogel nanocomposites

    Science.gov (United States)

    Swaroop, K.; Somashekarappa, H. M.

    2017-05-01

    Ag/PVA hydrogels nanocomposites (HNC's) of different Ag concentrations were synthesized using gamma irradiation technique. The prepared hydrogels were characterized using powder XRD, UV, SEM and TEM analysis. The equilibrium and dynamic swelling properties of different concentrations of Ag/PVA HNC's were studied. It has been observed that the swelling properties of the Ag/PVA HNC's increase with the Ag concentration. L-ascorbic acid was loaded to Ag/PVA HNC's and the release data was monitored by the absorption wavelength at 252 nm. The results indicate that both swelling and the ascorbic acid release process of Ag/PVA HNC's follows non-Fickian mechanism.

  15. Effect of different electrolytes on the swelling properties of calyx[4]pyrrole-containing polyacrylamide membranes

    OpenAIRE

    Valente,Artur J. M.; Sobral, Abílio J. F. N.; Jiménez, Alfonso; Patachia, Sílvia; Oliveira, Ana R. C. B.; Lobo, Victor M. M.

    2006-01-01

    Calix[4]pyrrole (1) was synthesized and characterized and this macrocycle was incorporated in polyacrylamide gels. The presence of meso-octamethyl-porphyrinogen inside of gel was checked using infrared spectroscopy, differential scanning calorimetry, and swelling studies. The swelling degree of these hydrogels in equilibrium with different electrolytes (NaCl, LiCl, KCl, CaCl2 and AlCl3) was measured in a concentration range 0.1-0.5 mol dm-3. Although no significant alterations in the swelling...

  16. Estimates of the eigenvalues of operator arising in swelling pressure model

    Energy Technology Data Exchange (ETDEWEB)

    Kanguzhin, Baltabek [Institute of Mathematics and Mathematical Modeling, 050010, Almaty (Kazakhstan); Zhapsarbayeva, Lyailya [Al-Farabi Kazakh National University, Almaty (Kazakhstan)

    2016-08-10

    Swelling pressures from materials confined by structures can cause structural deformations and instability. Due to the complexity of interactions between expansive solid and solid-liquid equilibrium, the forces exerting on retaining structures from swelling are highly nonlinear. This work is our initial attempt to study a simplistic spectral problem based on the Euler-elastic beam theory and some simplistic swelling pressure model. In this work estimates of the eigenvalues of some initial/boundary value problem for nonlinear Euler-elastic beam equation are obtained.

  17. Anesthetic concerns in a huge congenital sublingual swelling obscuring airway access

    Directory of Open Access Journals (Sweden)

    Nilesh Kumar

    2015-01-01

    Full Text Available Presence of intraoral pathology poses a great challenge during management of pediatric airway. We report management of big intraoral cystic swelling physically occupying the entire oral cavity restricting access to airway. Preintubation aspiration of swelling was done to decrease its size and make room for airway manipulation, followed by laryngoscopy and intubation in lateral position. Airway patency is at risk in postoperative period also, in this case, though the swelling decreased in size postoperatively but presence of significant edema required placement of tongue stitch and modified nasopharyngeal airway. Case report highlights simple maneuvers to manage a difficult case.

  18. Facile synthesis of glucose-sensitive chitosan-poly(vinyl alcohol) hydrogel: Drug release optimization and swelling properties.

    Science.gov (United States)

    Abureesh, Mosab Ali; Oladipo, Akeem Adeyemi; Gazi, Mustafa

    2016-09-01

    The study describes the development of glucose-sensitive hydrogel and optimization of bovine serum albumin release profile from the hydrogel. To enhance the glucose sensitivity and improve the swelling behaviors of the hydrogel system, boric acid crosslinking, and freeze-thawing cycle techniques were used to prepare chitosan-poly(vinyl alcohol) hydrogel. The structure of the resultant hydrogel was confirmed by scanning electron microscopy and Fourier transform infrared spectroscopy. The experimental results revealed that the swelling of the hydrogel was influenced by the pH of the medium, and the hydrogel displayed explicit glucose-sensitivity under physiological conditions. The values of the diffusion exponent range between 0.34 and 0.44 and the diffusion of water into the gel system are assumed to be pseudo-Fickian in nature. Under optimized conditions, the cumulative Bovine serum albumin (BSA) drug releases ranged between 69.33±1.95% and 86.45±1.16% at 37°C in the presence of glucose and pH 7.4, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. The bending elasticity of surfactant monolayers and bilayers and its effect on the swelling of free liquid films

    NARCIS (Netherlands)

    Barneveld, P.A.

    1991-01-01

    The present study was carried out to obtain more insight into the unusual swelling behaviour of surfactant layers. Here, swelling means that the thickness of the water layer between two surfactant layers increases. It was shown recently that high salt concentrations can bring about swelling

  20. A rare cause of calf swelling: the Morel–Lavallee lesion

    Science.gov (United States)

    Borrero, C. G.; Kavanagh, E. C.

    2009-01-01

    Introduction Calf swelling is a common clinical presentation with a wide and varied differential diagnosis. The Morel–Lavallee is a rare cause of subcutaneous swelling, caused by post-traumatic shearing of the hypodermis from the underlying fascia. The potential space so created fills with blood, lymph and necrotic fat giving specific findings on MR evaluation. Materials and methods A case of a 53-year-old man with calf swelling is presented, with clinical and MRI correlation. Treatment options and clinical course are discussed. Conclusion The Morel–Lavallee lesion is a rare but important cause of calf swelling. MRI is the mainstay of diagnosis and treatment includes both surgical and minimally invasive modalities. PMID:19618237

  1. Influence of monomer and crosslinker molar ratio on the swelling behaviour of thermosensitive hydrogels

    National Research Council Canada - National Science Library

    Ilić-Stojanović Snežana S; Nikolić Ljubiša; Nikolić Vesna; Stanković Mihajlo; Stamenković Jakov; Mladenović-Ranisavljević Ivana; Petrović Slobodan

    2012-01-01

    ... of monomer and crosslinker molar ratios on the swelling behaviour was investigated. Synthesis of thermosensitive hydrogel based on N-isopropylacrylamide was carried out with the molar ratios of 5, 10, 15 and 20 mol...

  2. On grain size dependent void swelling in pure copper irradiated with fission neutrons

    DEFF Research Database (Denmark)

    Singh, B.N.; Eldrup, Morten Mostgaard; Zinkle, S.J.

    2001-01-01

    The effect of grain size on void swelling has its origin in the intrinsic property of grain boundaries as neutral and unsaturable sinks for both vacancies and self-interstitial atoms (SIAs). The phenomenon was investigated already in the 1970s and it wasdemonstrated that the grain size dependent...... cascade damage conditions was radically different and could not be explained in terms of the SRT. In an effort to understand the source of this significantdifference, the effect of grain size on void swelling under cascade damage conditions has been investigated both experimentally and theoretically...... was calculated within the framework of the production biasmodel (PBM) and the SRT. The grain size dependent void swelling measured experimentally is in good accord with the theoretical results obtained using PMB. Implications of these results on modeling of void swelling under cascade damage conditions...

  3. Characteristics of long-period swells measured in the near shore regions of eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Johnson, G.; SanilKumar, V.; Amrutha, M.M.; Singh, J.

    experienced a reduction in efficiency of cargo handling operations and mooring line breakages and structural damages to facilities and the factors identified for the cause were vessel and mooring characteris- tics, long-period swells and its orientation...

  4. Massive swelling of the cervical region: an uncommon manifestation of B cell chronic lymphocytic leukemia.

    Science.gov (United States)

    Becker, Stephan T; Wiltfang, Jörg; Klapper, Wolfram; Repp, Roland; Sinis, Nektarios; Warnke, Patrick H

    2008-12-01

    We report about a 61-year-old woman who attended our Department of Oral and Maxillofacial Surgery complaining about an increasing swelling of her neck over a period of several years and asking for possible plastic surgery options. Further examinations lead us to the diagnosis of an uncommon manifestation of chronic B cell lymphoma. We suggest that plastic surgeons may refer to magnetic resonance tomography imaging and blood cell counts prior to liposuction of a massive swelling of the neck. Accurate reduction of adipose tissue in the obese patient is a common field for plastic surgeons. Thus, liposuction has become a standard regimen to treat adipose swelling. But there may be exceptions to the rule. In this case report, we present an uncommon manifestation of a chronic lymphocytic leukemia which showed a massive soft swelling of the whole neck, mimicking Madelung's disease.

  5. The effect of swelling agent on the pore characteristics of mesoporous hydroxyapatite nanoparticles

    Directory of Open Access Journals (Sweden)

    L. Bakhtiari

    2015-06-01

    Full Text Available The effect of swelling agent on the physicochemical properties of mesoporous hydroxyapatite particles synthesized by self-assembly process has been investigated. Cetyl trimethylammonium bromide (CTAB and 1-dodecanethiol were used as soft template and swelling agent respectively. The results of the field emission scanning electron microscopy (FESEM, X-ray diffraction (XRD, simultaneous thermal analysis (STA, Brunauer-Emmett-Teller (BET surface area, small-angle X-ray diffraction and Fourier transform infrared spectroscopy (FTIR assessments revealed that in the case of low concentration, 1-dodecanethiol performed as swelling agent and caused an increase in the pore size. However, at higher concentrations it led to the formation of microemulsion and foamy structures. The optimum swelling agent: surfactant mass ratio in synthesis of mesoporous hydroxyapatite particles with high pore volume was determined to be around 2.1 in this study.

  6. Effect of compression therapy on knee swelling and pain after total knee arthroplasty

    DEFF Research Database (Denmark)

    Munk, Stig; Jensen, Niels J. F.; Andersen, Ida Bøgh

    2013-01-01

    PURPOSE: Knee swelling after total knee arthroplasty may impair postoperative mobilisation and training, and as medical elastic compression stockings are well tolerated and effective to prevent oedema, haematoma and postoperative pain after venous surgery, we wanted to study whether this effect...... could be transferred to total knee arthroplasty surgery reducing postoperative swelling and pain and thereby facilitating mobilisation and improving patient-reported knee function. METHODS: In a randomised controlled study, 88 patients were randomised to use either a medical elastic compression stocking...... or no stocking from the first postoperative day and the following 4 weeks after total knee arthroplasty. Outcome measures were knee, calf and ankle swelling, knee flexion, pain and patient-reported knee function. RESULTS: Seventy per cent of the swelling had occurred before application of the stocking the day...

  7. Finite Element Investigations on the Interaction between a Pile and Swelling Clay

    DEFF Research Database (Denmark)

    Kaufmann, Kristine Lee; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust

    This paper aims to investigate the interaction between a pile and a swelling soil modelled as a cohesive soil subjected to unloading. The investigations include analyses of the heave of the excavation level, shear stresses at the soil–pile interface and internal pile forces based on a case study...... of Little Belt Clay. The case study involves a circular concrete pile installed in clay immediately after an excavation. The influence of the swelling soil on the soil–pile interaction and the internal pile forces are analysed by solely observing the upper pile part positioned in the swelling zone....... For the investigated case study, the influence of the pile is observed in a radius of approximately 3 pile diameters from the pile centre creating a weak zone inside this radius. The maximum heave of the excavation level inside this radius decreases polynomially with increasing interface strength. The swelling...

  8. Swelling and stacking fault formation in helium implanted SiC

    Energy Technology Data Exchange (ETDEWEB)

    Barbot, J.F., E-mail: jean.francois.barbot@univ-poitiers.fr [Institut Pprime, UPR3346, CNRS-Universite de Poitiers-ENSMA, Department of Material Sciences, SP2MI, Bd. M. et P. Curie, Teleport 2, BP 30179, F-86962 Futuroscope - Chasseneuil (France); Beaufort, M.F. [Institut Pprime, UPR3346, CNRS-Universite de Poitiers-ENSMA, Department of Material Sciences, SP2MI, Bd. M. et P. Curie, Teleport 2, BP 30179, F-86962 Futuroscope - Chasseneuil (France); Texier, M. [IM2NP Faculte des Sciences et Techniques, Campus de Saint Jerome, av. Escadrille Normandie Niemen, F-13397 Marseille Cedex (France); Tromas, C. [Institut Pprime, UPR3346, CNRS-Universite de Poitiers-ENSMA, Department of Material Sciences, SP2MI, Bd. M. et P. Curie, Teleport 2, BP 30179, F-86962 Futuroscope - Chasseneuil (France)

    2011-06-30

    Effects of annealing on surface swelling in helium implanted 4H-SiC were studied for different implant conditions. The significant increase of surface swelling observed upon high temperature annealing of samples implanted under severe implant conditions (high temperature and fluence) is observed to be concomitant with the growth of cavities and the formation of other extended defects in the highly damaged zone. Frank loops resulting from the drift of interstitials only form in the highly damaged zone. These loops promote the formation of Shockley partial dislocations leading to stacking fault pile-up. For less severe conditions of implantation, low temperature and fluence, the formation of dislocations is avoided upon post-annealing, and the recovery of swelling progressively occurs. Under intermediate conditions of implantation, the compensation between elastic recovery of the implantation-induced strain and the limited formation of cavities and interstitial-type clusters result in a constant swelling.

  9. The increased swelling and instantaneous deformation of osteoarthritic cartilage is highly correlated with collagen degradation.

    Science.gov (United States)

    Bank, R A; Soudry, M; Maroudas, A; Mizrahi, J; TeKoppele, J M

    2000-10-01

    To provide evidence for the hypothesis that the loss of tensile strength of osteoarthritic (OA) cartilage (resulting in swelling-the hallmark of OA) is due to an impaired collagen network and not to loss or degradation of proteoglycans. The amount of degraded collagen molecules, the fixed charge density (FCD) on a dry-weight basis, the degree of swelling in saline, and the instantaneous deformation (ID; a test reflecting the tensile stiffness of the collagen network) were measured in full-depth OA femoral condyle samples. In addition, levels of the crosslink hydroxylysylpyridinoline (HP), the amount of degraded collagen molecules, and the degree of swelling were determined in the 3 zones (surface, middle, and deep) of OA cartilage. We also compared the ID of normal and OA cartilage. In full-depth OA cartilage, a close relationship was found between swelling and ID. Swelling and ID correlated strongly with the amount of degraded collagen molecules, and were not related to FCD. OA cartilage showed the same zonal pattern in HP levels as normal cartilage (i.e., an increase with depth). No relationship was found between collagen crosslinking and swelling of the surface, middle, and deep zones. In all 3 zones, swelling was proportional to the amount of degraded collagen molecules. Compared with that of normal cartilage, the change in ID of OA cartilage was most pronounced at the surface in a direction parallel to the direction of the collagen fibrils. The decreased stiffness of the OA collagen network (as measured by swelling and ID) is strongly related to the amount of degraded collagen molecules. The anisotropy in ID parallel and perpendicular to the direction of the fibrils revealed that the impairment of strength resides mainly in, and not between, the fibrils. Proteoglycans play only a minor role in the degeneration of the tensile stiffness of OA cartilage.

  10. Decreased STAT3 Phosphorylation Mediates Cell Swelling in Ammonia-Treated Astrocyte Cultures

    Directory of Open Access Journals (Sweden)

    Arumugam R. Jayakumar

    2016-12-01

    Full Text Available Brain edema, due largely to astrocyte swelling, and the subsequent increase in intracranial pressure and brain herniation, are major complications of acute liver failure (ALF. Elevated level of brain ammonia has been strongly implicated in the development of astrocyte swelling associated with ALF. The means by which ammonia brings about astrocyte swelling, however, is incompletely understood. Recently, oxidative/nitrosative stress and associated signaling events, including activation of mitogen-activated protein kinases (MAPKs, as well as activation of the transcription factor, nuclear factor-kappaB (NF-κB, have been implicated in the mechanism of ammonia-induced astrocyte swelling. Since these signaling events are known to be regulated by the transcription factor, signal transducer and activator of transcription 3 (STAT3, we examined the state of STAT3 activation in ammonia-treated cultured astrocytes, and determined whether altered STAT3 activation and/or protein expression contribute to the ammonia-induced astrocyte swelling. STAT3 was found to be dephosphorylated (inactivated at Tyrosine705 in ammonia-treated cultured astrocytes. Total STAT3 protein level was also reduced in ammonia-treated astrocytes. We also found a significant increase in protein tyrosine phosphatase receptor type-1 (PTPRT-1 protein expression in ammonia-treated cultured astrocytes, and that inhibition of PTPRT-1 enhanced the phosphorylation of STAT3 after ammonia treatment. Additionally, exposure of cultured astrocytes to inhibitors of protein tyrosine phosphatases diminished the ammonia-induced cell swelling, while cultured astrocytes over-expressing STAT3 showed a reduction in the astrocyte swelling induced by ammonia. Collectively, these studies strongly suggest that inactivation of STAT3 represents a critical event in the mechanism of the astrocyte swelling associated with acute liver failure.

  11. Variations in swells along Eastern Arabian Sea during the summer monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Johnson, G.; SanilKumar, V.; Sanjiv, P.C.; Singh, J.; Pednekar, P.S.; AshokKumar, K.; Dora, G.U.; Gowthaman, R.

    facilities. The presence of local wind sea and swell components propagating from distant storms can be identified by studying wave energy spectra. When seas and swells are present the wave energy spectrum will be multi-peaked with peaks corresponding...- responding to the maximum spectral energy density is referred as spectral peak period (Tp) and is estimated from the wave spectrum. Other parameters obtained were spectral narrowness parameter () [6] and the maximum spectral energy. Zero...

  12. The kinetics of swelling of southern bean mosaic virus: a study using photon correlation spectroscopy.

    Science.gov (United States)

    Brisco, M; Haniff, C; Hull, R; Wilson, T M; Sattelle, D B

    1986-01-15

    Southern bean mosaic virus swells upon removal of Ca2+ at pH 8.25. Virions do not seem to aggregate significantly; the z-average hydrodynamic diameter increases from 29.9 nm to 44.0 nm. Swelling is virtually complete within 3 min, and swollen virions have a z-average hydrodynamic diameter similar to that of virions swollen by dialysis overnight.

  13. Swelling compositions based polycarboxylic acids and bentonite clays in solutions of salts of metals

    Directory of Open Access Journals (Sweden)

    A. Sarshesheva

    2012-12-01

    Full Text Available This work is devoted to the synthesis of chemical cross-linked composite materials made of natural inorganic polymer bentonite clay of Manrak deposit, and polyacrylic and polymethacrylic acids. The swelling ability of the composition in solutions of salts of heavy metals (Ni2+ and Pb2+, influence of solution of concentration, pH and temperature on the swelling ability is investigated.

  14. Influence of swelling and diffusion-induced convection on polymer sorption processes

    OpenAIRE

    Alsoy, Sacide; Duda, John Larry

    2002-01-01

    Unsteady-state sorption of a vapor or liquid by a polymer is modeled to include the influence of the moving phase boundary associated with the polymer swelling and diffusion-induced convection. A formulation presented clearly elucidates the influence of these two effects on the overall sorption process. Numerical solutions of the model equations indicate the errors that can be induced when swelling or convection are neglected. For most polymer-solvent systems, the influence of the diffusion-i...

  15. Penis swelling due to foreign body reaction after injection of silicone.

    Science.gov (United States)

    Plaza, Tobias; Lautenschlager, Stephan

    2010-09-01

    A 19-year-old man presented with phimosis and painful swelling of the penis four weeks after augmentation with silicone in Thailand. Histology revealed a foreign body reaction to silicone. Infectious causes were ruled out. Granulomatous foreign body reactions to silicone are common, but there are few case reports on reactions following silicone injection for penis enlargement. Foreign body reactions should be included in the differential diagnosis of penis swelling.

  16. The Compressibility and Swell of Mixtures for Sand-Clay Liners

    Directory of Open Access Journals (Sweden)

    Muawia A. Dafalla

    2017-01-01

    Full Text Available Sand-clay liners utilize expansive clay to act as a filler to occupy the voids in the sand and thus reduce the hydraulic conductivity of the mixture. The hydraulic conductivity and transfer of water and other substances through sand-clay mixtures are of prime concern in the design of liners and hydraulic barriers. Many successful research studies have been undertaken to achieve appropriate mixtures that satisfy hydraulic conductivity requirements. This study investigates compressibility and swelling properties of mixtures to ensure that they were acceptable for light structures, roads, and slabs on grade. A range of sand-expansive clay mixtures were investigated for swell and compression properties. The swelling and compressibility indices were found to increase with increasing clay content. The use of highly expansive material can result in large volume changes due to swell and shrinkage. The inclusion of less expansive soil material as partial replacement of bentonite by one-third to two-thirds is found to reduce the compressibility by 60% to 70% for 10% and 15% clay content, respectively. The swelling pressure and swell percent were also found significantly reduced. Adding less expansive natural clay to bentonite can produce liners that are still sufficiently impervious and at the same time less problematic.

  17. Modeling and Investigation of the Swelling Kinetics of Acrylamide-Sodium Acrylate Hydrogel

    Directory of Open Access Journals (Sweden)

    Azmi Seyhun Kipcak

    2014-01-01

    Full Text Available The acrylamide-sodium acrylate hydrogel was synthesized by free radical polymerization of the method of solution polymerization. Dynamic swelling tests were conducted at 25, 40, and 60°C temperatures, in order to investigate the swelling properties of the synthesized hydrogel. The results have shown that swelling content and swelling rate of the hydrogel increase with increasing the swelling water temperature. The diffusivity values changed from 1.81×10-7 to 2.97×10-7 m2 s−1 over the temperature range. The activation energies were found as 3.56, 3.71, and 3.86 kJ mol−1 at 25, 40, and 60°C, respectively. The experimental drying curves obtained were fitted to a three different models, namely, Peleg’s, first-order absorption kinetic, and exponential association equation models. All the models applied provided a good agreement with the experimental data with high values of the coefficient of determination (R2, the least values of the reduced chi-square (χ2, and root mean square error (RMSE. Comparing the determination of coefficient, reduced chi-square, and root mean square error values of three models, it was concluded that the exponential association equation model represents swelling characteristics better than the others.

  18. How Much Do Ultrathin Polymers with Intrinsic Microporosity Swell in Liquids?

    KAUST Repository

    Ogieglo, Wojciech

    2016-09-13

    As synthetic membrane materials, polymers with intrinsic microporosity (PIMs) have demonstrated unprecedented permeation and molecular-separation properties. Here, we report the swelling characteristics of submicron-thick supported films of spirobisindane-based PIMs, PIM-1 and PIM-6FDA-OH, for six organic solvents and water using in situ spectroscopic ellipsometry. Surprisingly, PIMs swell significantly in most organic solvents, with swelling factors (SF = h/h) as high as 2.5. This leads to the loss of the ultrarigid character of the polymer and produces equilibrated liquid-like swollen films. Filling of the excess frozen-in fractional free volume with liquid was discovered next to swelling-induced polymer matrix dilation. Water hardly swells the polymer matrix, but it penetrates into the intrinsic microporous structure. This study is the first to provide fundamental swelling data for PIMs, leading to better comprehension of their permeation properties. Such an understanding is indispensable for applications such as solvent filtration, natural-gas separation, and ion retention in flow batteries.

  19. A structural model for the in vivo human cornea including collagen-swelling interaction

    Science.gov (United States)

    Cheng, Xi; Petsche, Steven J.; Pinsky, Peter M.

    2015-01-01

    A structural model of the in vivo cornea, which accounts for tissue swelling behaviour, for the three-dimensional organization of stromal fibres and for collagen-swelling interaction, is proposed. Modelled as a binary electrolyte gel in thermodynamic equilibrium, the stromal electrostatic free energy is based on the mean-field approximation. To account for active endothelial ionic transport in the in vivo cornea, which modulates osmotic pressure and hydration, stromal mobile ions are shown to satisfy a modified Boltzmann distribution. The elasticity of the stromal collagen network is modelled based on three-dimensional collagen orientation probability distributions for every point in the stroma obtained by synthesizing X-ray diffraction data for azimuthal angle distributions and second harmonic-generated image processing for inclination angle distributions. The model is implemented in a finite-element framework and employed to predict free and confined swelling of stroma in an ionic bath. For the in vivo cornea, the model is used to predict corneal swelling due to increasing intraocular pressure (IOP) and is adapted to model swelling in Fuchs' corneal dystrophy. The biomechanical response of the in vivo cornea to a typical LASIK surgery for myopia is analysed, including tissue fluid pressure and swelling responses. The model provides a new interpretation of the corneal active hydration control (pump-leak) mechanism based on osmotic pressure modulation. The results also illustrate the structural necessity of fibre inclination in stabilizing the corneal refractive surface with respect to changes in tissue hydration and IOP. PMID:26156299

  20. Hygroscopic Swelling Determination of Cellulose Nanocrystal (CNC) Films by Polarized Light Microscopy Digital Image Correlation.

    Science.gov (United States)

    Shrestha, Shikha; Diaz, Jairo A; Ghanbari, Siavash; Youngblood, Jeffrey P

    2017-05-08

    The coefficient of hygroscopic swelling (CHS) of self-organized and shear-oriented cellulose nanocrystal (CNC) films was determined by capturing hygroscopic strains produced as result of isothermal water vapor intake in equilibrium. Contrast enhanced microscopy digital image correlation enabled the characterization of dimensional changes induced by the hygroscopic swelling of the films. The distinct microstructure and birefringence of CNC films served in exploring the in-plane hygroscopic swelling at relative humidity values ranging from 0% to 97%. Water vapor intake in CNC films was measured using dynamic vapor sorption (DVS) at constant temperature. The obtained experimental moisture sorption and kinetic profiles were analyzed by fitting with Guggenheim, Anderson, and deBoer (GAB) and Parallel Exponential Kinetics (PEK) models, respectively. Self-organized CNC films showed isotropic swelling, CHS ∼0.040 %strain/%C. By contrast, shear-oriented CNC films exhibited an anisotropic swelling, resulting in CHS ∼0.02 and ∼0.30 %strain/%C, parallel and perpendicular to CNC alignment, respectively. Finite element analysis (FEA) further predicted moisture diffusion as the predominant mechanism for swelling of CNC films.

  1. How Much Do Ultrathin Polymers with Intrinsic Microporosity Swell in Liquids?

    Science.gov (United States)

    Ogieglo, Wojciech; Ghanem, Bader; Ma, Xiaohua; Pinnau, Ingo; Wessling, Matthias

    2016-10-06

    As synthetic membrane materials, polymers with intrinsic microporosity (PIMs) have demonstrated unprecedented permeation and molecular-separation properties. Here, we report the swelling characteristics of submicron-thick supported films of spirobisindane-based PIMs, PIM-1 and PIM-6FDA-OH, for six organic solvents and water using in situ spectroscopic ellipsometry. Surprisingly, PIMs swell significantly in most organic solvents, with swelling factors (SF = h swollen /h dry ) as high as 2.5. This leads to the loss of the ultrarigid character of the polymer and produces equilibrated liquid-like swollen films. Filling of the excess frozen-in fractional free volume with liquid was discovered next to swelling-induced polymer matrix dilation. Water hardly swells the polymer matrix, but it penetrates into the intrinsic microporous structure. This study is the first to provide fundamental swelling data for PIMs, leading to better comprehension of their permeation properties. Such an understanding is indispensable for applications such as solvent filtration, natural-gas separation, and ion retention in flow batteries.

  2. Swelling of plutonium alloys. Measurements by optical fiber dilatometry; Gonflement des alliages de plutonium. Mesures par dilatometrie a fibre optique

    Energy Technology Data Exchange (ETDEWEB)

    Julia, P.; Gras-Naulin, N. [CEA - Centre de Valduc - 21120 Is-sur-Tille (France)

    2006-07-01

    Swelling is certainly the most remarkable effect of the plutonium alloys aging. This phenomenon has been experimentally observed as well at the macroscopic scale than at the microscopic scale on delta phase stabilized alloys. The continuous measurement of the macroscopic swelling is carried out by an original technique of Bragg lattice optical fibers dilatometry (transformation of a dimensional variation to a spectral shift). The obtained results show that the swelling begins without observing a latency period. The swelling kinetics presents two distinct phases: a transient phase followed by a linear phase. The evolution of the swelling seems to be sensitive to temperature. (O.M.)

  3. Bacterial cellulose based hydrogel (BC-g-AA) and preliminary result of swelling behavior

    Energy Technology Data Exchange (ETDEWEB)

    Hakam, Adil; Lazim, Azwan Mat [UKM-MIMOS Laboratory, School of Chemical Sciences and Food Technology, National University of Malaysia (UKM) (Malaysia); Abdul Rahman, I. Irman [Laboratory of Gamma Radiation Instrument, Science Nuclear Program, School of Applied Physics, National University of Malaysia (UKM) (Malaysia)

    2013-11-27

    In this study, hydrogel based on Bacterial cellulose (BC) or local known as Nata de Coco, which grafted with monomer: Acrylic acid (AA) is synthesis by using gamma radiation technique. These hydrogel (BC-g-AA) has unique characteristic whereby responsive to pH buffer solution.

  4. The Effects of the Thickness and Type of Silicone Coating Materials on the Swelling Behaviour of Hydrogels

    Science.gov (United States)

    Radzi, Zamri; Lee, J. Hannah; Swan, Marc; Goodacre, Tim; Bucknall, David; Czernuszka, Jan

    2010-03-01

    Encapsulation is one of the methods to control the degree of hydrogel swelling. In certain medical applications the hydrogels are required to undergone slow initial swelling before they start to gradually swell up to their maximum swelling capacity. Using a dip coating technique, the anisotropic hydrogels were coated with different types of silicone dispersion formulations. The hydrogels were swelled and measured by determining the mass change as a function of time. By varying the coating thickness and concentration of silicone we found that it is possible to slow down the initial swelling and allow the subsequent swelling process to gradually take place to physiologically acceptable levels. This behaviour has been analysed in terms of the permeability to water of the silicone membranes and their mechanical properties.

  5. Role of Defects in Swelling and Creep of Irradiated SiC

    Energy Technology Data Exchange (ETDEWEB)

    Szlufarska, Izabela [Univ. of Wisconsin, Madison, WI (United States); Voyles, Paul [Univ. of Wisconsin, Madison, WI (United States); Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States); Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-01-16

    Silicon carbide is a promising cladding material because of its high strength and relatively good corrosion resistance. However, SiC is brittle and therefore SiC-based components need to be carefully designed to avoid cracking and failure by fracture. In design of SiC-based composites for nuclear reactor applications it is essential to take into account how mechanical properties are affected by radiation and temperature, or in other words, what strains and stresses develop in this material due to environmental conditions. While thermal strains in SiC can be predicted using classical theories, radiation-induced strains are much less understood. In particular, it is critical to correctly account for radiation swelling and radiation creep, which contribute significantly to dimensional instability of SiC under radiation. Swelling typically increases logarithmically with radiation dose and saturates at relatively low doses (damage levels of a few dpa). Consequently, swelling-induced stresses are likely to develop within a few months of operation of a reactor. Radiation-induced volume swelling in SiC can be as high as 2%, which is significantly higher than the cracking strain of 0.1% in SiC. Swelling-induced strains will lead to enormous stresses and fracture, unless these stresses can be relaxed via some other mechanism. An effective way to achieve stress relaxation is via radiation creep. Although it has been hypothesized that both radiation swelling and radiation creep are driven by formation of defect clusters, existing models for swelling and creep in SiC are limited by the lack of understanding of specific defects that form due to radiation in the range of temperatures relevant to fuel cladding in light water reactors (LWRs) (<1000°C). For example, defects that can be detected with traditional transmission electron microscopy (TEM) techniques account only for 10-45% of the swelling measured in irradiated SiC. Here, we have undertaken an integrated experimental and

  6. [Species Determination and Spectral Characteristics of Swelling Clay Minerals in the Pliocene Sandstones in Xinghai, Qinghai].

    Science.gov (United States)

    Wang, Chao-wen; Chen, Jiang-jun; Fang, Qian; Yin, Ke; Hong, Han-lie

    2015-10-01

    X-ray diffraction (XRD) and Fourier infrared absorption spectroscopy (FTIR) were conducted to deepen our research on specific species and spectral characteristics of swelling clay minerals in the Pliocene sandstones in Xinghai, Qinghai province. XRD results show that swelling clay minerals are dominant clay minerals in the sandstones, which can be up to 97% in percentage. XRD patterns show 060 reflections of the samples occur both remarkably at 1.534 Å and 1.498 Å, indicating the samples contain physical mixtures of trioctahedral and dioctahedral swelling clay minerals, respectively. Further treatment of Li-300 degrees C heat and glycerol saturation shows the swelling clay minerals collapse to 9.3-9.9 Å with a partial expansion to -18 Å. This indicates the swelling clay minerals dominate montmorillonite and contain minor saponite. The montmorillonite shows no swelling after Li-300 degrees C heat and glycerol saturation because of Li+ inserting into the octahedral layers, which balances the layer charge caused by the substitution of Mg to Al. FTIR results show the samples are composed of a kind of phyllosilicate with absorbed and structural water, which is in agreement with the results of XRD. Absorbed peaks at 913, 842, 880 cm(-1), corresponding to OH associated with Al-Al, Al-Mg, and Al-Fe pairs, further indicates the minerals are dominant dioctahedron in structure. Meanwhile, absorbed peaks at 625 and 519 cm(-1), corresponding to coupled Si-O and Al-O-Si deformation, indicates parts of Si is replaced by Al in tetrahedron. The spectral characteristics of the samples are against the presence of beidellite and nontronite based on the results of XRD and FTIR, while demonstrating an,existence of montmorillonite. This study, to distinguish the specific species of swelling clay species in clay minerals, would be of great importance when using clay mineralogy to interpret provenance and climatic information.

  7. A preliminary reactive transport approach to quantify swelling of clay-sulfate rocks

    Science.gov (United States)

    Schweizer, D.; Prommer, H.; Blum, P.; Butscher, C.; Siade, A. J.

    2016-12-01

    The processes underlying the swelling of clay-sulfate rocks are complex and have been the subject of numerous previous investigations. In general, the transformation of anhydrite into gypsum is considered the main mechanism of swelling, a process that is likely initiated by a change in hydraulic conditions, followed by influx of water and a change in geochemistry. Furthermore, it is accompanied by a volume increase of 61 % and a heat production of 28 kJ/mol. However, hydraulic and geochemical processes in the swelling zone, typically induced by construction measures such as borehole drillings, remain difficult to assess. In this study a numerical model was developed and applied to a site in Staufen, Germany, where significant swelling occurred in clay-sulfate rocks as a result of geothermal drillings. We used a field-scale dual-domain reactive transport modeling approach to investigate and quantify the importance of groundwater influx and geochemical reactions within the swelling zone. The observed swelling process was conceptualized through (i) a mobile domain that accounts for water flux and solute transport along preferential flow paths (PFP); and (ii) an immobile `reactive' domain considering the rate-limited transformation of anhydrite into gypsum. The model development was constrained by geodesic heave measurements at the ground surface as well as vertical temperature profiles. Both data types could be related to the predicted increase in rock volume and release of heat caused by the exothermal reaction, respectively. Compared to reported reaction rates of anhydrite dissolution and gypsum precipitation determined in laboratory experiments, our calibrated model yields considerably lower effective reaction rates. It was found that transport by PFP as well as the mass transfer between domains and therefore water availability impose a strong control on the magnitude and spatial extent of the simulated swelling process.

  8. Overnight corneal swelling with high and low powered silicone hydrogel lenses.

    Science.gov (United States)

    Moezzi, Amir M; Fonn, Desmond; Varikooty, Jalaiah; Simpson, Trefford L

    2015-01-01

    To compare central corneal swelling after eight hours of sleep in eyes wearing four different silicone hydrogel lenses with three different powers. Twenty-nine neophyte subjects wore lotrafilcon A (Dk, 140), balafilcon A (Dk, 91), galyfilcon A (Dk, 60) and senofilcon A (Dk, 103) lenses in powers -3.00, -10.00 and +6.00 D on separate nights, in random order, and on one eye only. The contra-lateral eye (no lens) served as the control. Central corneal thickness was measured using a digital optical pachometer before lens insertion and immediately after lens removal on waking. For the +6.00 D and -10.00 D, lotrafilcon A induced the least swelling and galyfilcon A the most. The +6.00 D power, averaged across lens materials, induced significantly greater central swelling than the -10.00 and -3.00 D (Re-ANOVA, p<0.001), (7.7±2.9% vs. 6.8±2.8% and 6.5±2.5% respectively) but there was no difference between -10.00 and -3.00 D. Averaged for power, lotrafilcon A induced the least (6.2±2.8%) and galyfilcon A the most (7.6±3.0%) swelling at the center (Re-ANOVA, p<0.001). Central corneal swelling with +6.00 D was significantly greater than -10.00 D lens power despite similar levels of average lens transmissibility of these two lens powers. The differences in corneal swelling of the lens wearing eyes are consistent with the differences in oxygen transmission of the silicone hydrogel lenses. In silicone hydrogel lenses central corneal swelling is mainly driven by central lens oxygen transmissibility. Copyright © 2013 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  9. Prediction of void swelling in the baffle ring of WWER-1000 reactors for service life of 30–60 years

    Energy Technology Data Exchange (ETDEWEB)

    Kalchenko, A.S., E-mail: kalchenko@kipt.kharkov.ua [National Science Center “Kharkov Institute of Physics and Technology”, 61108 Kharkov (Ukraine); Bryk, V.V.; Lazarev, N.P.; Voyevodin, V.N. [National Science Center “Kharkov Institute of Physics and Technology”, 61108 Kharkov (Ukraine); Garner, F.A. [Radiation Effects Consulting, Richland, WA 99354 (United States)

    2013-06-15

    Major internal components of WWER-type nuclear reactors are made from annealed 18Cr10NiTi steel, a close analog to AISI 321. Void swelling of the baffle ring in particular could be a major factor limiting operation of the reactor beyond the current 30 years license. A predictive swelling equation is needed to forecast the spatial variation of swelling so as to identify those areas requiring additional attention. Available data on the swelling of this steel arising from irradiation in the BOR-60 fast reactor was combined with data from a heavy ion accelerator at higher displacement rates to formulate a predictive equation of swelling for the WWER-relevant range of temperature, irradiation dose and dose rates. This equation was used to estimate the swelling distribution over a cross-section of the baffle ring of a WWER reactor during a service life up to 60 years, reaching a local maximum of ∼30% swelling. It was shown that void swelling extends over a larger portion of the baffle ring than previously expected and exhibits a very complex and irregular distribution in response to complex distributions of temperature and dpa rate. Most importantly, as operation is extended beyond 30 years several areas of the ring may experience swelling in excess of 10% where void-induced embrittlement begins and one area may exceed 20% after 45 years, a swelling level where a complete loss of ductility is known to occur.

  10. Predicting the volumetric variation due to changes in suction, applied stress and swelling pressure

    Directory of Open Access Journals (Sweden)

    Galaviz-González Roberto

    2016-01-01

    Full Text Available The settlements produced by the load transmitted to the structure on expansive soils, and those calculated by the classical theories of soil mechanics, are different because the swelling pressure acts inversely to the applied stress. In this paper we describe a procedure to determine a volumetric variation coefficient by hydration (αh which considers the expansive soil behaviour. In order to do this, it is necessary to know the soil’s initial water content, the swelling pressure, and the applied stress. Soil suction and swelling pressure were measured with filter paper technique and a mechanical oedometer, respectively. Unsaturated undisturbed samples of expansive soil were used. The water content was varied, starting from 0%, with increments of 5.5% to reach 38%. Furthermore, we present a set of curves that show the magnitude of the coefficient (αh associated to a water content, and the relationship between applied stress and swelling pressure. The results show that the variation of the coefficient under different initial water contents ranges between 0% to 22%. This is because water is strongly attracted by clay minerals, but this attraction decreases as water layers are father from the surface of clay minerals, thus decreasing its swelling potential.

  11. Swelling kinetics and impregnation of PLA with thymol under supercritical CO2 conditions

    Directory of Open Access Journals (Sweden)

    Milovanović Stoja L.

    2016-01-01

    Full Text Available The present work was aimed to study swelling kinetics of polylactic acid (PLA and its impregnation with thymol in supercritical carbon dioxide (scCO2 medium. The influences of temperature and soaking time on the swelling kinetics and impregnation yield of PLA cylindrical disc and film were investigated. Swelling experiments were performed in a high pressure view cell at 10 MPa and temperatures of 40°C, 60°C and 75°C for 2 to 24 h. On the basis of swelling kinetics, pressure of 10 MPa and temperature of 40°C were chosen for supercritical solvent impregnation (SSI of the PLA samples during 2 to24 h. The highest swelling extent was observed for the PLA monolith after 24 h treatment with pure scCO2 (7.5% and scCO2 with thymol (118.3%. It was shown that sufficiently high amount of thymol can be loaded into both PLA monolith and film using SSI after only 2 h (10.0% and 6.6%, respectively. Monolith and film of PLA impregnated with thymol could be suitable for active food packaging and sterile medical disposables.

  12. Characterization and swelling-deswelling properties of wheat straw cellulose based semi-IPNs hydrogel.

    Science.gov (United States)

    Liu, Jia; Li, Qian; Su, Yuan; Yue, Qinyan; Gao, Baoyu

    2014-07-17

    A novel wheat straw cellulose-g-poly(potassium acrylate)/polyvinyl alcohol (WSC-g-PKA/PVA) semi-interpenetrating polymer networks (semi-IPNs) hydrogel was prepared by polymerizing wheat straw and an aqueous solution of acrylic acid (AA), and further semi-interpenetrating with PVA occurred during the chemosynthesis. The swelling and deswelling properties of WSC-g-PKA/PVA semi-IPNs hydrogel and WSC-g-PKA hydrogel were studied and compared in various pH solutions, salt solutions, temperatures, particle sizes and ionic strength. The results indicated that both hydrogels had the largest swelling capacity at pH=6, and the effect of ions on the swelling of hydrogels was in the order: Na(+)>K(+)>Mg(2+)>Ca(2+). The Schott's pseudo second order model can be effectively used to evaluate swelling kinetics of hydrogels. Moreover, the semi-IPNs hydrogel had improved swelling-deswelling properties compared with that of WSC-g-PKA hydrogel. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Swelling Dynamics of a DNA-Polymer Hybrid Hydrogel Prepared Using Polyethylene Glycol as a Porogen

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    Ming Gao

    2015-11-01

    Full Text Available DNA-polyacrylamide hybrid hydrogels designed with covalent and double-stranded (dsDNA crosslinks respond to specific single-stranded DNA (ssDNA probes by adapting new equilibrium swelling volume. The ssDNA probes need to be designed with a base pair sequence that is complementary to one of the strands in a dsDNA supported network junction. This work focuses on tuning the hydrogel swelling kinetics by introducing polyethylene glycol (PEG as a pore-forming agent. Adding PEG during the preparation of hydrogels, followed by removal after polymerization, has been shown to improve the swelling dynamics of DNA hybrid hydrogels upon specific ssDNA probe recognition. The presence of porogen did not influence the kinetics of osmotic pressure-driven (2-acrylamido-2-methylpropane sulfonic acid-co-acrylamide (AMPSA-co-AAm hydrogels’ swelling, which is in contrast to the DNA-sensitive hydrogels. The difference in the effect of using PEG as a porogen in these two cases is discussed in view of processes leading to the swelling of the gels.

  14. Anions Govern Cell Volume: A Case Study of Relative Astrocytic and Neuronal Swelling in Spreading Depolarization.

    Directory of Open Access Journals (Sweden)

    Niklas Hübel

    Full Text Available Cell volume changes are ubiquitous in normal and pathological activity of the brain. Nevertheless, we know little about the dynamics of cell and tissue swelling, and the differential changes in the volumes of neurons and glia during pathological states such as spreading depolarizations (SD under ischemic and non-ischemic conditions, and epileptic seizures. By combining the Hodgkin-Huxley type spiking dynamics, dynamic ion concentrations, and simultaneous neuronal and astroglial volume changes into a comprehensive model, we elucidate why glial cells swell more than neurons in SD and the special case of anoxic depolarization (AD, and explore the relative contributions of the two cell types to tissue swelling. Our results demonstrate that anion channels, particularly Cl-, are intrinsically connected to cell swelling and blocking these currents prevents changes in cell volume. The model is based on a simple and physiologically realistic description. We introduce model extensions that are either derived purely from first physical principles of electroneutrality, osmosis, and conservation of particles, or by a phenomenological combination of these principles and known physiological facts. This work provides insights into numerous studies related to neuronal and glial volume changes in SD that otherwise seem contradictory, and is broadly applicable to swelling in other cell types and conditions.

  15. Stress state dependence of in-reactor creep and swelling. Part 2: Experimental results

    Science.gov (United States)

    Hall, M. M., Jr.; Flinn, J. E.

    2010-01-01

    Irradiation creep constitutive equations, which were developed in Part I, are used here to analyze in-reactor creep and swelling data obtained ca. 1977-1979 as part of the US breeder reactor program. The equations were developed according to the principles of incremental continuum plasticity for the purpose of analyzing data obtained from a novel irradiation experiment that was conducted, in part, using Type 304 stainless steel that had been previously irradiated to significant levels of void swelling. Analyses of these data support an earlier observation that all stress states, whether tensile, compressive, shear or mixed, can affect both void swelling and interactions between irradiation creep and swelling. The data were obtained using a set of five unique multiaxial creep-test specimens that were designed and used for the first time in this study. The data analyses demonstrate that the constitutive equations derived in Part I provide an excellent phenomenological representation of the interactive creep and swelling phenomena. These equations provide nuclear power reactor designers and analysts with a first-of-its-kind structural analysis tool for evaluating irradiation damage-dependent distortion of complex structural components having gradients in neutron damage rate, temperature and stress state.

  16. Hygroscopic swelling and shrinkage of latewood cell wall micropillars reveal ultrastructural anisotropy.

    Science.gov (United States)

    Rafsanjani, Ahmad; Stiefel, Michael; Jefimovs, Konstantins; Mokso, Rajmund; Derome, Dominique; Carmeliet, Jan

    2014-06-06

    We document the hygroscopic swelling and shrinkage of the central and the thickest secondary cell wall layer of wood (named S2) in response to changes in environmental humidity using synchrotron radiation-based phase contrast X-ray tomographic nanoscopy. The S2 layer is a natural fibre-reinforced nano-composite polymer and is strongly reactive to water. Using focused ion beam, micropillars with a cross section of few micrometres are fabricated from the S2 layer of the latewood cell walls of Norway spruce softwood. The thin neighbouring cell wall layers are removed to prevent hindering or restraining of moisture-induced deformation during swelling or shrinkage. The proposed experiment intended to get further insights into the microscopic origin of the anisotropic hygro-expansion of wood. It is found that the swelling/shrinkage strains are highly anisotropic in the transverse plane of the cell wall, larger in the normal than in the direction parallel to the cell wall's thickness. This ultrastructural anisotropy may be due to the concentric lamellation of the cellulose microfibrils as the role of the cellulose microfibril angle in the transverse swelling anisotropy is negligible. The volumetric swelling of the cell wall material is found to be substantially larger than the one of wood tissues within the growth ring and wood samples made of several growth rings. The hierarchical configuration in wood optimally increases its dimensional stability in response to a humid environment with higher scales of complexity.

  17. pH responsive cross-linked polymeric matrices based on natural polymers: effect of process variables on swelling characterization and drug delivery properties

    Directory of Open Access Journals (Sweden)

    Fahad Naeem

    2017-08-01

    Full Text Available Introduction: The current work was aimed to design and synthesize novel crosslinked pH-sensitive gelatin/pectin (Ge/Pec hydrogels using different polymeric ratios and to explore the effect of polymers and degree of crosslinking on dynamic, equilibrium swelling and in vitro release behavior of the model drug (Mannitol. Methods: The Ge/Pec based hydrogels were prepared using glutaraldehyde as the crosslinker. Various structural parameters that affect their release behavior were determined, including swelling study, porosity, sol-gel analysis, average molecular weight between crosslinks (Mc, volume fraction of polymer (V2,s, solvent interaction parameter (χ and diffusion coefficient. The synthesized hydrogels were subjected to various characterization tools like Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD and DSC differential scanning calorimetry (DSC and scanning electron microscopy (SEM. Results: The hydrogels show highest water uptake and release at lower pH values. The FTIR spectra showed an interaction between Ge and Pec, and the drug-loaded samples also showed the drug-related peaks, indicating proper loading of the drug. DSC and TGA studies confirmed the thermal stability of hydrogel samples, while SEM showed the porous nature of hydrogels. The drug release followed non-Fickian diffusion or anomalous mechanism. Conclusion: Aforementioned characterizations reveal the successful formation of copolymer hydrogels. The pH-sensitive swelling ability and drug release behavior suggest that the rate of polymer chain relaxation and drug diffusion from these hydrogels are comparable which also predicts their possible use for site-specific drug delivery.

  18. A three-scale model for ionic solute transport in swelling clays incorporating ion-ion correlation effects

    Science.gov (United States)

    Le, Tien Dung; Moyne, Christian; Murad, Marcio A.

    2015-01-01

    attractive forces between particles for bivalent ions for particular ranges of bulk concentrations. The three-scale model is applied to numerically simulate ion diffusion in a compacted clay liner underneath a sanitary landfill. Owing to the distinct constitutive behavior of the swelling pressure and partition coefficient for each ionic species, different compaction regimes and diffusion/adsorption patterns, with totally different characteristic time scales, are observed for sodium and calcium migration in the clay liner.

  19. Ion irradiation-induced swelling and hardening effect of Hastelloy N alloy

    Science.gov (United States)

    Zhang, S. J.; Li, D. H.; Chen, H. C.; Lei, G. H.; Huang, H. F.; Zhang, W.; Wang, C. B.; Yan, L.; Fu, D. J.; Tang, M.

    2017-06-01

    The volumetric swelling and hardening effect of irradiated Hastelloy N alloy were investigated in this paper. 7 MeV and 1 MeV Xe ions irradiations were performed at room temperature (RT) with irradiation dose ranging from 0.5 to 27 dpa. The volumetric swelling increases with increasing irradiation dose, and reaches up to 3.2% at 27 dpa. And the irradiation induced lattice expansion is also observed. The irradiation induced hardening initiates at low ion dose (≤1dpa) then saturates with higher ion dose. The irradiation induced volumetric swelling may be ascribed to excess atomic volume of defects. The irradiation induced hardening may be explained by the pinning effect where the defects can act as obstacles for the free movement of dislocation lines. And the evolution of the defects' size and number density could be responsible for the saturation of hardness.

  20. Investigation of the swelling behaviour of hydrogels in aqueous acid or alkaline solutions

    Science.gov (United States)

    Althans, Daniel; Enders, Sabine

    2014-09-01

    For development of tailor made drug delivery systems using poly(N-isopropylacrylamide) hydrogels, the influence of acids and bases added to the aqueous solution on the swelling behaviour as function of concentration, temperature and kind of acid or base were investigated experimentally. The selected acids are formic, acetic, propionic, lactic, succinic, α-ketoglutaric and citric acid. The applied bases are sodium and potassium hydroxide. The swelling behaviour was characterised by the degree of swelling and by the uptake of acids by the hydrogel in the swollen state. In the case of weak acids the properties of the swollen hydrogel as well as the phase transition temperature and phase transition acid concentration depends on the type of acids, whereas the properties of the shrunken state do not depend on the acid used. In the case of strong bases, the properties of the shrunken and swollen state depend on the ionic strength, but not on the base applied.

  1. Swelling and water transport in temperature-sensitive hydrogels based on 2-methoxyethylacrylate

    Energy Technology Data Exchange (ETDEWEB)

    Martellini, F. E-mail: martelli@net.ipen.br; Mei, L.H.I.; Balino, J.L.; Carenza, M. E-mail: carenza@frae.bo.cnr.it

    2002-01-01

    A series of thermoresponsive hydrogels based on copolymers of 2-methoxyethylacrylate with acrylamide or N,N-dimethylacrylamide were prepared by radiation-induced polymerization in dimethylformamide solution in the presence of a crosslinking agent. The swelling behaviour of the hydrogels was studied by immersing the polymer samples in water at 5 deg. C, 10 deg. C and 37 deg. C. The data were found to satisfactorily fit Fick's law with a constant diffusion coefficient. The results indicate that the swelling ratio increases with increasing the content of the hydrophilic monomers in the hydrogels and at the same time the equilibrium swelling time decreases. The effect of temperature on water transport mechanism was observed.

  2. Measurement of water transfer and swelling stress in the buffer material due to temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, H. [ITC, Tokai, Ibaraki (Japan); Chijimatsu, M.; Fujita, A.

    1999-03-01

    Coefficients concerning the water transfer in the buffer material was obtained by empirically giving a temperature gradient, and the swelling stress was measured when water was soaked in the sample under the uniform temperature and temperature gradient conditions. The distributions of temperature and water in the buffer material empirically given a temperature gradient were measured to deduce water diffusion constant due to the temperature gradient. The diffusion constant was the order of 10{sup -8} cm{sup 2}/s/degC. As a result of a equitemperature soaking test, it was found that the swelling stress of the part where soaktion was slow was greater than that of the part with fast soaking at a stage of non-uniform water distribution. The water soaking quantity to the sample and swelling stress reached a stationary state after 7000 hours and the water distribution in the whole sample was found saturated. (H. Baba)

  3. Cellulose nanocrystal interactions probed by thin film swelling to predict dispersibility

    Science.gov (United States)

    Reid, Michael S.; Villalobos, Marco; Cranston, Emily D.

    2016-06-01

    The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of the interactions between components. Measuring the cohesive particle-particle interactions and the adhesive particle-polymer interactions is challenging due to nanoscale dimensions and poor colloidal stability of nanoparticles in many solvents. We demonstrate a new cohesive interaction measurement method using cellulose nanocrystals (CNCs) as a model system; CNCs have recently gained attention in the composites community due to their mechanical strength and renewable nature. Multi-wavelength surface plasmon resonance spectroscopy (SPR) was used to monitor the swelling of CNC thin films to elucidate the primary forces between CNCs. This was achieved by measuring swelling in situ in water, acetone, methanol, acetonitrile, isopropanol, and ethanol and relating the degree of swelling to solvent properties. Films swelled the most in water where we estimate 1.2-1.6 nm spacings between CNCs (or 4-6 molecular layers of water). Furthermore, a correlation was found between film swelling and the solvent's Hildebrand solubility parameter (R2 = 0.9068). The hydrogen bonding component of the solubility parameters was more closely linked to swelling than the polar or dispersive components. The films remained intact in all solvents, and using DLVO theory we have identified van der Waals forces as the main cohesive interaction between CNCs. The trends observed suggest that solvents (and polymers) alone are not sufficient to overcome CNC-CNC cohesion and that external energy is required to break CNC agglomerates. This work not only demonstrates that SPR can be used as a tool to measure cohesive particle-particle interactions but additionally advances our fundamental understanding of CNC interactions which is necessary for the design of cellulose nanocomposites.The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of

  4. Erythrocyte swelling and membrane hole formation in hypotonic media as studied by conductometry.

    Science.gov (United States)

    Pribush, A; Meyerstein, D; Hatskelzon, L; Kozlov, V; Levi, I; Meyerstein, N

    2013-02-01

    Hypoosmotic swelling of erythrocytes and the formation of membrane holes were studied by measuring the dc conductance (G). In accordance with the theoretical predictions, these processes are manifested by a decrease in G followed by its increase. Thus, unlike the conventional osmotic fragility test, the proposed methodological approach allows investigations of both the kinetics of swelling and the erythrocyte fragility. It is shown that the initial rate of swelling and the equilibrium size of the cells are affected by the tonicity of a hypotonic solution and the membrane rheological properties. Because the rupture of biological membranes is a stochastic process, a time-dependent increase in the conductance follows an integral distribution function of the membrane lifetime. The main conclusion which stems from reported results is that information about rheological properties of red blood cell (RBC) membranes and the resistivity of RBCs to a certain osmotic shock may be extracted from conductance signals.

  5. Extracranial soft-tissue swelling: a normal postmortem radiographic finding or a sign of trauma?

    Energy Technology Data Exchange (ETDEWEB)

    Strouse, P.J. [Section of Pediatric Radiology, University of Michigan Medical Center, Ann Arbor (United States); Caplan, M. [Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan (United States); Owings, C.L. [Department of Pediatrics and Communicable Diseases, C. S. Mott Children`s Hospital, Ann Arbor, Michigan (United States)

    1998-08-01

    Objective. To determine if extracranial soft-tissue swelling is an expected postmortem finding or a sign of trauma. Materials and methods. Extracranial soft-tissue thickness was measured at 5 standardized locations on postmortem skull films obtained of 18 infants with no evidence of trauma on autopsy. The same measurements were performed on the skull films of 100 living children, all less than 3 years old and without clinical history of trauma. Results. Extracranial soft tissues measured only slightly greater in the postmortem group than on films of living children; however, the difference did achieve statistical significance. Conclusion. Minimal extracranial soft-tissue swelling is a normal finding on a postmortem skeletal survey. The presence of substantial or asymmetric extracranial soft-tissue swelling should be viewed with suspicion for trauma. (orig.) With 2 tabs., 5 refs.

  6. Recurrence of acute lymphoblastic leukemia manifesting as serous retinal detachments and optic disc swelling.

    Science.gov (United States)

    Yabas Kiziloglu, Ozge; Mestanoglu, Mert; Totuk Gedar, Ozgun Melike; Adiguzel, Cafer; Toygar, Okan

    2017-07-15

    The aim of this case report is to describe a patient with acute lymphoblastic leukemia (ALL) who developed bilateral serous retinal detachments and unilateral optic disc swelling. A 23-year-old woman with ALL presented to the ophthalmology clinic with bilateral subacute visual loss. Ophthalmologic examination revealed bilateral serous retinal detachments and unilateral optic disc swelling. Magnetic resonance imaging for differential diagnosis was inconclusive; however, cerebrospinal fluid sampling demonstrated leukemic involvement of the central nervous system. The patient's vision improved and fundus findings resolved with the institution of systemic and intrathecal chemotherapy. Serous retinal detachment and optic disc swelling are unusual ocular manifestations of ALL. They may occur due to leukemic infiltration of ocular structures and may indicate extramedullary recurrence of the disease. Early recognition and treatment is crucial to improve prognosis.

  7. Swelling of radiation crosslinked acrylamide-based microgels and their potential applications

    Energy Technology Data Exchange (ETDEWEB)

    Abd El-Rehim, H.A. [National Center for Radiation Research and Technology, Atomic Energy Authority, P.O. Box 29 Nasr City, Cairo (Egypt)]. E-mail: ha_rehim@hotmail.com

    2005-10-01

    Crosslinked polyacrylamide PAAm and acrylamide-Na-acrylate P(AAm-Na-AAc) microgels were prepared by electron beam irradiation. It was found that the dose required for crosslinking depends on the polymer moisture content, so that the dose to obtain PAAm of maximum gel fraction was over 40 and 20 kGy for dry and moist PAAm, respectively. The structural changes in irradiated PAAm were investigated using FTIR and SEM. The swelling property of such microgels in distilled water and real urine solution was determined and crosslinked polymers reached their equilibrium swelling state in a few minutes. As the gel content and crosslinking density decrease, the swelling of the microgels increases. The ability of the microgels to absorb and retain large amount of solutions suggested their possible uses in horticulture and in hygienic products such as disposable diapers.

  8. Tensile, swelling and morphological properties of bentonite-filled acrylonitrile butadiene rubber composites

    Science.gov (United States)

    Lotfi, Muhamad Nadhli Amin; Ismail, Hanafi; Othman, Nadras

    2017-10-01

    Tensile, swelling and morphological properties of bentonite filled acrylonitrile butadiene rubber (NBR/Bt) composites were studied. The experiments were conducted at room temperature by using two rolled mill, universal testing machine (INSTRON), and American Standard Testing Method (ASTM) D471 for compounding, tensile testing, and swelling test, respectively. Results obtained indicated that a better tensile strength, elongation at break and tensile modulus were recorded as compared to the pure NBR particularly up to 90 phr of Bt loading. However, swelling (%) exhibited the opposite trend where the liquid uptake by the composites was indirectly proportional with the increasing of Bt loading. Scanning electron microscopy (SEM) used on the tensile fractured surface of the NBR/Bt composites have shown that the fillers were well embedded in the NBR matrix, for Bt loading up to 90 phr. The agglomeration of fillers occurred for Bt loading exceeding 90 phr.

  9. Blends of hydrophobic and swelling agents in the swelling layer in the preparation of delayed-release pellets of a hydrophilic drug with low MW: Physicochemical characterizations and in-vivo evaluations

    Directory of Open Access Journals (Sweden)

    Chang You

    2014-08-01

    Full Text Available In this study, a hydrophobic material, ethylcellulose, which was used as its aqueous suspension Surelease®, was combined with a swelling agent as the swelling layer to prepare delayed-release pellets for Danshensu, which is a hydrophilic drug with low MW. A rupturable, delayed-release pellet consists of a drug core, a swelling layer containing a swelling agent (cross-linked sodium carboxymethyl cellulose with a hydrophobic agent (Surelease®, and a controlled layer composed by an insoluble, water-permeable polymeric coating (aqueous ethylcellulose dispersions was developed in a fluidised bed. Results showed that blending Surelease® into the swelling layer could effectively extend the release of Danshensu from the pellets, which may be attributed to the slowed swelling rate by reduction of water penetration and improvement of mechanical integrity of the swelling layer. Drug in the delayed pellets showed sustained release in beagle dogs after oral administration with comparable in-vivo exposure to the uncoated drug pellets. In conclusion, blends of hydrophobic and swelling agents in the swelling layer in double-membrane pellets could achieve a delayed drug-release profile in vitro, as well as delayed and sustained absorption in vivo for highly soluble, low-MW drug. The present study highlighted the potential use of a delayed-release system for other hydrophilic, low-MW drugs to meet the formulation requirements for chronopharmacological diseases.

  10. Experimental Anterior Ischemic Optic Neuropathy in Diabetic Mice Exhibited Severe Retinal Swelling Associated With VEGF Elevation.

    Science.gov (United States)

    Sun, Ming-Hui; Shariati, Mohammad Ali; Liao, Yaping Joyce

    2017-04-01

    Diabetes mellitus (DM) is one of the most important risk factors for nonarteritic anterior ischemic optic neuropathy (AION). In this study, we investigated for the first time the impact of experimental AION in a DM model. We induced a photochemical thrombosis model of AION after streptozotocin-induced DM and performed serial optical coherence tomography (OCT), morphometric analyses, and VEGF levels in the retina and sera. Compared with non-DM animals, experimental AION in DM mice led to significantly greater retinal swelling on day 1 and worse thinning at week 3 on OCT measurements. Greater retinal swelling on OCT in DM-AION eyes was associated with significantly increased loss of brain-specific homeobox/POU domain protein 3A (Brn3A+) retinal ganglion cells at week 3. In acute AION, there was greater inflammation as seen by an increase in ionized calcium-binding adapter molecule 1 (Iba1+)-activated microglia. On day 1, there was increase in vascular endothelial growth factor (VEGF) level in nondiabetic AION retinae and sera, but the VEGF level was the highest in the diabetic AION group, which decreased to nondiabetic levels after insulin treatment. The decrease in retinal and serum VEGF levels after insulin treatment correlated with a reduction in retinal swelling. In the setting of hyperglycemia, AION led to greater acute, postischemic microglial activation and elevation of VEGF levels, which likely contributed to greater retinal swelling acutely and worse retinal thinning and loss of retinal ganglion cells chronically. Treatment of hyperglycemia with insulin reduced VEGF levels and retinal swelling, consistent with the idea that VEGF is an important factor in postischemic swelling and that good glycemic control following AION may lead to better visual outcome.

  11. A structural model for the in vivo human cornea including collagen-swelling interaction.

    Science.gov (United States)

    Cheng, Xi; Petsche, Steven J; Pinsky, Peter M

    2015-08-06

    A structural model of the in vivo cornea, which accounts for tissue swelling behaviour, for the three-dimensional organization of stromal fibres and for collagen-swelling interaction, is proposed. Modelled as a binary electrolyte gel in thermodynamic equilibrium, the stromal electrostatic free energy is based on the mean-field approximation. To account for active endothelial ionic transport in the in vivo cornea, which modulates osmotic pressure and hydration, stromal mobile ions are shown to satisfy a modified Boltzmann distribution. The elasticity of the stromal collagen network is modelled based on three-dimensional collagen orientation probability distributions for every point in the stroma obtained by synthesizing X-ray diffraction data for azimuthal angle distributions and second harmonic-generated image processing for inclination angle distributions. The model is implemented in a finite-element framework and employed to predict free and confined swelling of stroma in an ionic bath. For the in vivo cornea, the model is used to predict corneal swelling due to increasing intraocular pressure (IOP) and is adapted to model swelling in Fuchs' corneal dystrophy. The biomechanical response of the in vivo cornea to a typical LASIK surgery for myopia is analysed, including tissue fluid pressure and swelling responses. The model provides a new interpretation of the corneal active hydration control (pump-leak) mechanism based on osmotic pressure modulation. The results also illustrate the structural necessity of fibre inclination in stabilizing the corneal refractive surface with respect to changes in tissue hydration and IOP. © 2015 The Author(s).

  12. Swelling behaviour of stones and its interest in conservation. An appraisal

    Directory of Open Access Journals (Sweden)

    Delgado Rodrigues, J.

    2001-12-01

    Full Text Available Swelling can be defined as the volume increase experienced by any solid body when wetted. Many lithotypes (carbonate rocks, sandstones, igneous rocks have expansive components in their composition; anhydrite and clay minerals are the two best-known expansive components in stone materials. Swelling strain can be easily quantified and swelling pressure determination is accessible in many geotechnical laboratories. This paper deals with the decay of stone due to swelling of clays and discusses the ways to take the swelling behaviour into account when the assessment of stone durability is concerned. It analyses the role of swelling in stone conservation and reviews some cases where this decay mechanism has a relevant role, explicit or implicitly.

    La expansibilidad puede ser definida como el incremento de volumen que un cuerpo sólido experimenta cuando es humedecido. Muchos tipos litológicos (rocas carbonatadas, areniscas, rocas ígneas tienen componentes expansivos en su composición; la anhidrita y los minerales arcillosos son los dos componentes expansivos más conocidos. La expansibilidad puede ser medida con facilidad y la determinación de la presión de hinchamiento se puede efectuar en muchos laboratorios de geotecnia. Este trabajo trata del problema de la degradación de los materiales rocosos debida a la expansión de las arcillas y discute las formas de tenerla en cuenta cuando interesa evaluar la durabilidad de esos materiales. Se analiza el papel de la expansibilidad en la conservación de la piedra y se hace una revisión de algunos casos en los que la degradación por expansión tiene un papel relevante, explícito o implícito.

  13. Top down analysis ceramide-induced mitochondrial dysfunctions: role of mitochondrial swelling.

    Science.gov (United States)

    Leducq, Nathalie; Macouillard-Poulletier de Gannes, Florence; Rotureau, Marc-Antoine Belaud; Belloc, Francis; Voisin, Pierre; Canioni, Paul; Diolez, Philippe

    2002-01-01

    Mitochondrial role in ceramide-induced apoptosis pathway remains unclear. Direct effects of ceramide on mitochondria (cytochrome c release, respiratory chain inhibition, oxygen radicals production...) have been reported [1, 2] and we previously showed that addition of ceramide to intact cells or isolated mitochondria triggers mitochondrial swelling which appeared to be insensitive to cyclosporin A (CsA) [3, 4]. The purpose of this work was to determine to which extent this CsA-insensitive mitochondrial swelling, therefore distinct from permeability transition, participates to ceramide-induced apoptosis. To achieve this, we applied Top-Down analysis of integrated mitochondrial function [5], in order to better understand ceramide-induced mitochondrial dysfunctions.

  14. Radiation myelopathy with spinal cord swelling occurring three years after irradiation. A case report

    Energy Technology Data Exchange (ETDEWEB)

    Okuda, Bungo; Okamoto, Kensho; Tagashira, Hiroshi [Ehime Prefectural Central Hospital (Japan)

    2002-02-01

    A 64-year-old woman developed progressive deterioration of sensations, gait, and bladder-bowel functions. The patient had suffered from malignant lymphoma in the neck, and underwent irradiation three years before admission. On admission, she exhibited cervical radiculomyelopathy including spastic tetraplegia, intrinsic muscle atrophy, sensory disturbance in the lower body, and sphincter disturbance. MRI showed diffuse high intensity in the cervical cord on T2-weighted image with Gd-enhancement on T1-weighted image. On serial MRI, swelling of the cervical cord progressed from 36 to 39 months after irradiation. Delayed swelling of the spinal cord can be associated with radiation myelopathy. (author)

  15. Transitory spinal cord swelling in a 6-year-old boy with Guillain-Barre syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Delhaas, T. [Section of Child Neurology, Wilhelmina Children`s Hospital, University Hospital for Children and Youth, Utrecht (Netherlands)]|[Department of Pediatrics, University Hospital Maastricht, P0 Box 5800, 6202 AZ Maastricht (Netherlands); Kamphuis, D.J. [Section of Child Neurology, Wilhelmina Children`s Hospital, University Hospital for Children and Youth, Utrecht (Netherlands); Witkamp, T.D. [Department of Radiology, University Hospital Utrecht, Utrecht (Netherlands)

    1998-07-01

    A 6-year-old boy developed progressive motor weakness and areflexia. The clinical picture, combined with electrophysiological findings, indicated a diagnosis of Guillain-Barre syndrome (GBS). MRI on admission revealed spinal cord swelling and increased signal intensity within the cord. It is concluded that, since a degree of central nervous system involvement can occasionally be part of the spectrum of GBS, swelling of the spinal cord without contrast enhancement does not exclude a diagnosis of GBS. (orig.) With 2 figs., 8 refs.

  16. Microstructure and anisotropic swelling behaviour of compacted bentonite/sand mixture

    Directory of Open Access Journals (Sweden)

    Simona Saba

    2014-04-01

    Full Text Available Pre-compacted elements (disks, torus of bentonite/sand mixture are candidate materials for sealing plugs of radioactive waste disposal. Choice of this material is mainly based on its swelling capacity allowing all gaps in the system to be sealed, and on its low permeability. When emplaced in the gallery, these elements will start to absorb water from the host rock and swell. Thereby, a swelling pressure will develop in the radial direction against the host rock and in the axial direction against the support structure. In this work, the swelling pressure of a small scale compacted disk of bentonite and sand was experimentally studied in both radial and axial directions. Different swelling kinetics were identified for different dry densities and along different directions. As a rule, the swelling pressure starts increasing quickly, reaches a peak value, decreases a little and finally stabilises. For some dry densities, higher peaks were observed in the radial direction than in the axial direction. The presence of peaks is related to the microstructure change and to the collapse of macro-pores. In parallel to the mechanical tests, microstructure investigation at the sample scale was conducted using microfocus X-ray computed tomography (μCT. Image observation showed a denser structure in the centre and a looser one in the border, which was also confirmed by image analysis. This structure heterogeneity in the radial direction and the occurrence of macro-pores close to the radial boundary of the sample can explain the large peaks observed in the radial swelling pressure evolution. Another interesting result is the higher anisotropy found at lower bentonite dry densities, which was also analysed by means of μCT observation of a sample at low bentonite dry density after the end of test. It was found that the macro-pores, especially those between sand grains, were not filled by swelled bentonite, which preserved the anisotropic microstructure caused by

  17. Water Vapor Sensors Based on the Swelling of Relief Gelatin Gratings

    Directory of Open Access Journals (Sweden)

    Sergio Calixto

    2015-01-01

    Full Text Available We report on a novel device to measure relative humidity. The sensor is based on surface diffraction gratings made of gelatin. This material swells and shrinks according to the content of water vapor in air. By sending a light beam to the grating, diffracted orders appear. Due to the gelatin swelling or shrinking, first order intensity changes according to the relative humidity. Calibration curves relating intensity versus relative humidity have been found. The fabrication process of diffraction gratings and the testing of the prototype sensing devices are described.

  18. Edge wave response on a barred beach with wind-sea and swell forcing

    Science.gov (United States)

    Contardo, Stephanie; Symonds, Graham; Segura, Laura

    2015-04-01

    The occurrence of short period wind-sea associated with a diurnal sea breeze, superimposed on longer period swell in South West Western Australia provides an opportunity to observe the response of infragravity (0.01-0.05 Hz) waves, in the nearshore, to both wind-sea and swell forcing. An alongshore array of pressure sensors and a cross-shore array of current velocity and pressure sensors are deployed at Secret Harbour, a barred beach near Perth. The observations show a stronger infragravity response to longer period incident swell than to short period wind-sea. Infragravity waves at Secret Harbour are generated by two mechanisms: breakpoint forcing and bound wave release. Breakpoint forcing is observed with both swell and wind-sea forcing while bound wave release is only observed in the presence of swell. Two mechanisms generate free infragravity waves during swell periods while only one mechanism is in place during wind-sea periods, providing an explanation for the stronger response to swell than wind-sea. Free infragravity waves propagating offshore after reflection at the shoreline are called leaky waves; those which are trapped to the shoreline by refraction are called edge waves. At Secret Harbour, both edge waves and leaky waves are detected. Leaky waves dominate with swell forcing while edge waves dominate with wind-sea forcing. Amongst edge waves, mode 0 waves are found to dominate in the absence of wind-sea, while higher mode edge waves dominate when wind-sea is present. We calculate the expected wavenumber-frequency distribution of edge wave and leaky wave energy, based on resonance conditions, using wave period, incidence angle and directional spreading, as proposed by Bowen and Guza (1978). Observations and predictions are in good agreement. However the model can be improved by quantifying the infragravity energy generated by both infragravity wave generation mechanisms. Bowen, A. J., and R. T. Guza (1978), Edge waves and surf beat, Journal of

  19. Swelling behaviour of Early Jurassic shales when exposed to water vapour

    Science.gov (United States)

    Houben, Maartje; Barnhoorn, Auke; Peach, Colin; Drury, Martyn

    2017-04-01

    The presence of water in mudrocks has a largely negative impact on production of gas, due to the fact that water causes swelling of the rock. Removing the water from the mudrock on the other hand could potentially shrink the rock and increase the matrix permeability. Investigation of the swelling/shrinkage behaviour of the rock during exposure to water vapour is of key importance in designing and optimizing unconventional production strategies. We have used outcrop samples of the Whitby Mudstone and the Posidonia shale [1], potential unconventional sources for gas in North-western Europe, to measure the swelling and shrinkage behaviour. Subsamples, 1 mm cubes, were prepared by the Glass Workshop at Utrecht University using a high precision digitally controlled diamond wafering saw cooled by air. The mm cubes were then exposed to atmospheres with different relative humidities either in an Environmental Scanning Electron Microscope (ESEM) or in a 3D dilatometer. So that the sample responses to exposure of water vapour could be measured. Parallel to the bedding we found a swelling strain between 0.5 and 1.5 %, perpendicular to the bedding though swelling strain varied between 1 and 3.5%. Volumetric swelling strain varied between 1 and 2% at a maximum relative humidity of 95%. Volumetric swelling strains measured in the Early Toarcian Shales are similar to the ones found in coal [2], where the results suggest that it might be possible to increase permeability in the reservoir by decreasing the in-situ water activity due to shrinkage of the matrix. [1] M.E. Houben, A. Barnhoorn, L. Wasch, J. Trabucho-Alexandre, C. J. Peach, M.R. Drury (2016). Microstructures of Early Jurassic (Toarcian) shales of Northern Europe, International Journal of Coal Geology, 165, 76-89. [2] Jinfeng Liu, Colin J. Peach, Christopher J. Spiers (2016). Anisotropic swelling behaviour of coal matrix cubes exposed to water vapour: Effects of relative humidity and sample size, International Journal of

  20. Large Plunging Ranula Presenting as Isolated Neck Swelling: Steps in Diagnosis and Surgical Steps in Management.

    Science.gov (United States)

    Nilesh, Kumar; Malik, Neelima A; Patil, Pankaj; Chapi, Mouneshkumar Devendrappa

    2015-06-01

    Ranula is a salivary gland cyst which typically present as localized superficial swelling over the floor of mouth. Complex or plunging ranulas develop when the mucus extravasation extends through or around the mylohyoid muscle, deeper into the neck, and present with neck lump along with or without swelling over floor of mouth. We report a case of large plunging ranula presenting as an isolated large neck mass in a 38-year-old female patient. The steps in diagnosis and surgical steps in management of the pathology are systematically described.

  1. Sonographic and MRI appearance of tensor fasciae suralis muscle, an uncommon cause of popliteal swelling

    Energy Technology Data Exchange (ETDEWEB)

    Montet, Xavier; Mauget, Denis [Departement de Radiologie, Division de Radiodiagnostic et Radiologie Interventionelle, Hopital cantonal Universitaire de Geneve, Rue Micheli-du-Crest 24, 1211 Geneva 14 (Switzerland); Sandoz, Alain [Specialiste FMH - Chirurgie orthopedique, Av. du Cardinal-Mermillod 36, 1227 Geneva (Switzerland); Martinoli, Carlo [Cattedra di Radiologia ' ' R' ' , DICMI-Universita di Genova, Largo Rosanna Benzi 8, 16132 Genoa (Italy); Bianchi, Stefano [Medecin associe, Departement de Radiologie, Division de Radiodiagnostic et Radiologie Interventionnelle, Hopital cantonal Universitaire de Geneve, Rue Micheli-du-Crest 24, 1211 Geneva 14 (Switzerland)

    2002-09-01

    A 20-year-old white man presented with a localized unilateral swelling in the popliteal fossa. Ultrasound (US) showed the presence of an accessory muscle, the tensor fasciae suralis. The muscle was located in the proximal portion of the popliteal fossa, superficial to the medial head of the gastrocnemius. Its long tendon extended inferiorly to join the Achilles tendon. Magnetic resonance images correlated well with the US findings, confirming the diagnosis. Tensor fasciae suralis muscle is a rare cause of popliteal swelling and must be differentiated from other masses. Both US and magnetic resonance imaging can diagnose it but we suggest US as the first-line technique in its evaluation. (orig.)

  2. Marked potentiation of cell swelling by cytokines in ammonia-sensitized cultured astrocytes

    Directory of Open Access Journals (Sweden)

    Tong Xiaoying

    2010-10-01

    Full Text Available Abstract Background Brain edema leading to high intracranial pressure is a lethal complication of acute liver failure (ALF, which is believed to be cytotoxic due to swelling of astrocytes. In addition to the traditional view that elevated levels of blood and brain ammonia are involved in the mechanism of brain edema in ALF, emerging evidence suggests that inflammatory cytokines also contribute to this process. We earlier reported that treatment of astrocyte cultures with a pathophysiological concentration of ammonia (5 mM NH4Cl resulted in the activation of nuclear factor-kappaB (NF-κB and that inhibition of such activation diminished astrocyte swelling, suggesting a key role of NF-κB in the mechanism of ammonia-induced astrocyte swelling. Since cytokines are also well-known to activate NF-κB, this study examined for additive/synergistic effects of ammonia and cytokines in the activation of NF-κB and their role in astrocyte swelling. Methods Primary cultures of astrocytes were treated with ammonia and cytokines (TNF-α, IL-1, IL-6, IFN-γ, each at 10 ng/ml, individually or in combination, and cell volume was determined by the [3H]-O-methylglucose equilibration method. The effect of ammonia and cytokines on the activation of NF-κB was determined by immunoblots. Results Cell swelling was increased by ammonia (43% and by cytokines (37% at 24 h. Simultaneous co-treatment with cytokines and ammonia showed no additional swelling. By contrast, cultures pretreated with ammonia for 24 h and then exposed to cytokines for an additional 24 h, showed a marked increase in astrocyte swelling (129%. Treatment of cultures with ammonia or cytokines alone also activated NF-κB (80-130%, while co-treatment had no additive effect. However, in cultures pre-treated with ammonia for 24 h, cytokines induced a marked activation of NF-κB (428%. BAY 11-7082, an inhibitor of NF-κB, completely blocked the astrocyte swelling in cultures pre-treated with ammonia and

  3. On grain-size-dependent void swelling in pure copper irradiated with fission neutrons

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Eldrup, Morten Mostgaard; Zinkle, S.J.

    2002-01-01

    The effect of grain size on void swelling has its origin in the intrinsic property of grain boundaries as neutral and unsaturable sinks for both vacancies and self-interstitial atoms. The phenomenon had already been investigated in the 1970s and it was demonstrated that the grain-size-dependent v...

  4. Reliability and validity of measurements of facial swelling with a stereophotogrammetry optical three-dimensional scanner

    NARCIS (Netherlands)

    van der Meer, Wicher J.; Dijkstra, Pieter U.; Visser, Anita; Vissink, Arjan; Ren, Yijin

    2014-01-01

    Volume changes in facial morphology can be assessed using the 3dMD DSP400 stereo-optical 3-dimensional scanner, which uses visible light and has a short scanning time. Its reliability and validity have not to our knowledge been investigated for the assessment of facial swelling. Our aim therefore

  5. Magnitude, modeling and significance of swelling and shrinkage processes in clay soils

    NARCIS (Netherlands)

    Bronswijk, J.J.B.

    1991-01-01

    The dynamic process of swelling and shrinkage in clay soils has significant practical consequences, such as the rapid transport of water and solutes via shrinkage cracks to the subsoil, and the destruction of buildings and roads on clay soils. In order to develop measuring methods and

  6. Bilateral breast swelling secondary to superior vena cava obstruction and subclavian vein thrombosis

    Directory of Open Access Journals (Sweden)

    Ariadne Mayumi Yamada

    2013-07-01

    Full Text Available Superior vena cava syndrome is defined by a set of signs and symptoms secondary to superior vena cava obstruction caused principally by malignant diseases. The present report describes the case of an unusual clinical manifestation of this syndrome with bilateral breast swelling, and emphasizes the relevance of knowledge on mammographic signs of systemic diseases.

  7. NFkappaB in the mechanism of ammonia-induced astrocyte swelling in culture.

    NARCIS (Netherlands)

    Sinke, A.P.; Jayakumar, A.R.; Panickar, K.S.; Moriyama, M.; Reddy, P.V.; Norenberg, M.D.

    2008-01-01

    Astrocyte swelling and brain edema are major neuropathological findings in the acute form of hepatic encephalopathy (fulminant hepatic failure), and substantial evidence supports the view that elevated brain ammonia level is an important etiological factor in this condition. Although the mechanism

  8. Second toe swelling: Nora's lesion or glomus tumour, case report and literature review.

    LENUS (Irish Health Repository)

    Mohammad, A

    2012-09-01

    We report a rare case of bizarre parosteal osteochondromatous proliferation (BPOP, Nora\\'s lesion) of the right second toe in a 60-year-old man who presented with painful, bluish and bulbous swelling of the right second toe without any break in the skin.

  9. Influence of monomer and crosslinker molar ratio on the swelling behaviour of thermosensitive hydrogels

    Directory of Open Access Journals (Sweden)

    Ilić-Stojanović Snežana S.

    2012-01-01

    Full Text Available The synthesis of the poly(N-isopropylacrylamide-co-2-hydroxypropylmethacrylate hydrogel along with the analysis of the residual monomers content and influence of monomer and crosslinker molar ratios on the swelling behaviour was investigated. Synthesis of thermosensitive hydrogel based on N-isopropylacrylamide was carried out with the molar ratios of 5, 10, 15 and 20 mol. % of monomer 2- hydroxypropyl-methacrylate, in the presence of ethylene glycol dimethacrylate as a crosslinker (1, 1.5, 2 and 3 mol. % and 2,2'-azobis(2-methylpropionitril as an initiator in acetone. The quantities of residual monomers in the synthesized copolymers were determined by HPLC method, ranging from 0.19 to 0.49 % for N-isopropylacrylamide and from 0.13 to 0.63 % for 2-hydroxypropyl-methacrylate, counting the amount of xerogel. The hydrogels swelling ratio depending on time at 20 and 40°C was examined. It was found that hydrogel with 5 mol. % 2-hydroxypropyl-methacrylate and 1 mol. % ethylene glycol dimethacrylate had the highest degree of swelling (α = 29.59 at 20°C, and that hydrogel with 20 mol. % 2-hydroxypropyl-methacrylate and 3 mol. % ethylene glycol dimethacrylate had the lowest swelling degree (α = 2.17 at 40°C.

  10. Simulating the swelling and deformation behaviour in soft tissues using a convective thermal analogy

    Directory of Open Access Journals (Sweden)

    Herzog Walter

    2002-12-01

    Full Text Available Abstract Background It is generally accepted that cartilage adaptation and degeneration are mechanically mediated. Investigating the swelling behaviour of cartilage is important because the stress and strain state of cartilage is associated with the swelling and deformation behaviour. It is well accepted that the swelling of soft tissues is associated with mechanical, chemical, and electrical events. Method The purpose of the present study was to implement the triphasic theory into a commercial finite element tool (ABAQUS to solve practical problems in cartilage mechanics. Because of the mathematical identity between thermal and mass diffusion processes, the triphasic model was transferred into a convective thermal diffusion process in the commercial finite element software. The problem was solved using an iterative procedure. Results The proposed approach was validated using the one-dimensional numerical solutions and the experimental results of confined compression of articular cartilage described in the literature. The time-history of the force response of a cartilage specimen in confined compression, which was subjected to swelling caused by a sudden change of saline concentration, was predicted using the proposed approach and compared with the published experimental data. Conclusion The advantage of the proposed thermal analogy technique over previous studies is that it accounts for the convective diffusion of ion concentrations and the Donnan osmotic pressure in the interstitial fluid.

  11. Propagation of Atlantic Ocean swells in the north Indian Ocean: A case study

    Digital Repository Service at National Institute of Oceanography (India)

    Samiksha, S.V.; Vethamony, P.; Aboobacker, V.M.; Rashmi, R.

    An analysis of altimeter significant wave height data of May 2007 revealed the occurrence of an extreme weather event off southern tip of South Africa in the Atlantic Ocean, and generation of a series of very high swells at 40 degrees S...

  12. Upper lip swelling caused by a large dentigerous cyst with mesiodens.

    Science.gov (United States)

    Khan, M H; Alam, M T; Haque, S; Khan, S H; Fatema, C N; Tahsin, T; Choudhury, A R

    2008-07-01

    Swelling of upper lip can results from various diseases such as salivary tumors, infections and inflammatory diseases and cyst, typically involving unerrupted teeth, are sometimes associated with supernumerary teeth in the maxillary anterior incisor region called the mesiodens. Mesiodens with dentigerous cyst is actually a rare case in the world and of course in Bangladesh. The overall prevalence of this type of cyst is only 0.15-1.9% of the total population. Recently we have experienced this kind of case like dentigerous cyst with mesiodens in the department of dentistry, Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders (BIRDEM) Hospital. The patient was 24 years old male young complaining of slow growing painless swelling on the upper lip region for the last several years. Clinical examination revealed a soft intra oral swelling in the labial surface of maxillary incisor region and there was also extra orally upper lip swelling. Radiographic examination demonstrated a large radiolucent area with a mesiodens extending to the root of both lateral incisors. The patient was treated surgically by enucleation of total cysts and surgical extraction of mesiodens under local anesthesia.

  13. Recent studies on wind seas and swells in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Vethamony, P.; Rashmi, R.; Samiksha, S.V.; Aboobacker, V.M.

    Winds and waves measured at a few locations along the west coast of India were analysed to study the wave characteristics in the deep as well as near shore regions during different seasons. The potential generation of swells observed in the Arabian...

  14. Swelling and tribological properties of melt-mixed fluoroelastomer/nitrile rubber blends under crude oil

    Science.gov (United States)

    Tagelsir, Yasin; Li, San-Xi; Lv, Xiaoren; Wang, Shijie; Wang, Song; Osman, Zeinab

    2018-01-01

    The melt-mixed fluoroelastomer (FKM)/ nitrile rubber (NBR) blends of (90/10, 80/20, 70/30, 60/40 and 50/50) ratios with same hardness were prepared, and their swelling and tribological properties under crude oil were investigated for the purpose of developing high performance cost-effective elastomers meeting requirement of oil extraction progressive cavity pump stator. Differential scanning calorimetry confirmed compatible blend system for all blends. Field emission scanning electron microscopy (FE-SEM) showed co-continuous morphology of 200–400 nm phase size for all blends, expect FKM/NBR (90/10) which exhibited partially continuous phase morphology of 100–250 nm phase size. The results of swelling and linear wear tests under crude oil indicated that swelling percentage, coefficient of friction and specific wear rate of FKM/NBR blends were much better than NBR, with FKM/NBR (90/10 and 80/20) showing swelling percentage and specific wear rate very close to FKM. Attenuated total reflectance-Fourier transform infrared spectroscopy disclosed that fracture of macromolecular chains was the main mechanochemical effect of unswollen and swollen worn surfaces, in addition to oxygenated degradation detected with increasing NBR ratio in the blends. The fracture of macromolecular chains resulted in slight fatigue wear mechanism, which was also confirmed by FE-SEM of the worn surfaces.

  15. A Rare Case of Paediatric Neck Swelling: Cervical Sympathetic Chain Schwannoma

    Directory of Open Access Journals (Sweden)

    E. Keane

    2013-01-01

    Full Text Available Schwannomas are indolent benign lesions arising from schwann cells in the nerve. They are especially rare in the paediatric population. We report an interesting case of a swelling in the upper neck, which highlights an atypical presentation of this tumour, as well as the complex details of its clinical, radiological, and surgical management.

  16. Sub-sarcolemmal swelling of sarcoplasmic reticulum after isometric contractions in rat semimembranosus lateralis muscle

    NARCIS (Netherlands)

    Willems, M.E.T.; Huijing, P.A.J.B.M.; Friden, J.

    1999-01-01

    The decline in isometric force, swelling of sarcoplasmic reticulum and loss of desmin was measured in semimembranosus lateralis muscle of male Wistar rats immediately after a short series of brief (500 ms) maximal isometric contractions. For the active muscle, the series ended below (protocol A) and

  17. Micromechanical Characterization of Hydrogels Undergoing Swelling and Dissolution at Alkaline pH

    Directory of Open Access Journals (Sweden)

    Wei Hu

    2017-11-01

    Full Text Available The swelling of polyelectrolyte hydrogels usually depends on the pH, and if the pH is high enough degradation can occur. A microindentation device was developed to dynamically test these processes in whey protein isolate hydrogels at alkaline pH 7–14. At low alkaline pH the shear modulus decreases during swelling, consistent with rubber elasticity theory, yet when chemical degradation occurs at pH ≥ 11.5 the modulus decreases quickly and extensively. The apparent modulus was constant with the indentation depth when swelling predominates, but gradients were observed when fast chemical degradation occurs at 0.05–0.1 M NaOH. In addition, these profiles were constant with time when dissolution rates are also constant, the first evidence that a swollen layer with steady state mechanical properties is achieved despite extensive dissolution. At >0.5 M NaOH, we provide mechanical evidence showing that most interactions inside the gels are destroyed, gels were very weak and hardly swell, yet they still dissolve very slowly. Microindentation can provide complementary valuable information to study the degradation of hydrogels.

  18. Obvious optic disc swelling in a patient with cryopyrin-associated periodic syndrome

    Directory of Open Access Journals (Sweden)

    Kawai M

    2013-08-01

    Full Text Available Mariko Kawai,1 Tadanobu Yoshikawa,1 Ryuta Nishikomori,2 Toshio Heike,2 Kanji Takahashi11Department of Ophthalmology, Kansai Medical University, Osaka, 2Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, JapanAbstract: Cryopyrin-associated periodic syndrome (CAPS is a group of rare hereditary autoinflammatory diseases caused by mutations of the NLRP3 gene, and leads to excessive production of the proinflammatory cytokine, interleukin-lß. A 35-year-old male presented with recurrent symptoms of urticarial-like rash, periodic fever, arthralgia, headache, and eye redness. His best-corrected visual acuity was 1.0 OD and 0.9 OS. Slit-lamp examination showed conjunctival and episcleral injection in both eyes. Ophthalmoscopy revealed obvious bilateral optic disc swelling and retinal vascular sheathing around the optic discs. Spectral domain optical coherence tomography also showed obvious optic disc swelling. Steroid and nonsteroidal anti-inflammatory drugs did not improve these symptoms. Genetic testing detected a heterozygous mutation of c.907G>A. Thus, the patient was genetically confirmed with CAPS. Visual acuity did not decrease for 3 years, although the optic discs became white in color. CAPS should therefore be distinguished from other disorders when examining optic disc swelling and/or uveitis patients with urticarial-like rash and periodic fever.Keywords: interleukin-lß, chronic infantile cutaneous and articular syndrome, cryopyrin-associated periodic syndrome, leucine-rich repeat-containing protein 3, optic disc swelling

  19. Alteration of non-swelling clay minerals and magadiite by acid activation

    NARCIS (Netherlands)

    Steudel, A.; Batenburg, L.F.; Fischer, H.R.; Weidler, P.G.; Emmerich, K.

    2009-01-01

    The bulk material of three kaolins, a sepiolite, an illite and one magadiite were treated with 1, 5 and 10 M H2SO4 at 80 °C for several hours. The alteration of the non-swelling clay mineral structures was controlled by the individual character of each mineral (chemical composition and initial

  20. Local Fission Gas Release and Swelling in Water Reactor Fuel during Slow Power Transients

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Walker, C.T.; Ray, I.L.F.

    1985-01-01

    Gas release and fuel swelling caused by a power increase in a water reactor fuel (burn-up 2.7–4.5% FIMA) is described. At a bump terminal level of about 400 W/cm (local value) gas release was 25–40%. The formation of gas bubbles on grain boundaries and their degree of interlinkage are the two...

  1. Throat ache ans swelling of the neck: first symptoms of Lemierre's syndrome

    NARCIS (Netherlands)

    de Lange, J.; Ybema, A; Baas, E. M.

    2014-01-01

    Lemierre's syndrome, a thrombophlebitis of the internal jugular vein, is a rare disorder, usually caused by the microorganism Fusobacterium necrophorum. Throat ache and swelling of the neck are often the first symptoms. Without adequate treatment, Lemierre's syndrome may result in thrombosis of the

  2. Development of swelling strain in smectite clays through exposure to carbon dioxide

    NARCIS (Netherlands)

    de Jong, S.M.; Spiers, C.J.|info:eu-repo/dai/nl/304829323; Busch, A.

    2014-01-01

    Smectites are common constituents of claystones, mudstones and shales and are often present in the caprocks and faults that seal potential CO2 storage reservoirs at depths up to 2 or even 3 km. Whilst the marked swelling behaviour of smectites caused by hydration through interlayer sorption of water

  3. Evaluation of hypoxic swelling of human cornea with high speed ultrahigh resolution optical coherence tomography

    Science.gov (United States)

    Bizheva, Kostadinka; Hyun, Chulho; Eichel, Justin; Hariri, Sepideh; Mishra, Akshaya; Clausi, David; Fieguth, Paul; Simpson, Trefford; Hutchings, Natalie

    2009-02-01

    Hypoxia induced corneal swelling was observed and evaluated in healthy human volunteers by use of high speed, ultrahigh resolution optical coherence tomography (UHROCT). Two dimensional corneal images were acquired at a speed of 47,000 A-scans/s with 3µm x 10µm (axial x lateral) resolution in corneal tissue. The UHROCT tomograms showed clear visualization of all corneal layers, including the Bowman's layer and the Descemet's membrane - Endothelium complex. A segmentation algorithm was developed and used for automatic detection of the boundaries of the different corneal layers and evaluation the individual layer thickness as a function of location. Corneal hypoxia was induced by wear of a soft contact lens (SCL) and an eye patch by 2 healthy volunteers for duration of 3 hours. The thickness of all corneal layers was measured as a function of time, prior to, with and after removal of the SCL. Results from the hypoxia study showed different rates of swelling and de-swelling of the individual corneal layers. About 10% increase in the total cornea thickness was observed, similar to the changes in the stroma, the Bowman's membrane swelled by 20%, while no significant change in the thickness was observed in the Descemet's - Endothelium complex.

  4. Ocean swell variability along the northern coast of the Gulf of Guinea ...

    African Journals Online (AJOL)

    This study analyses a 4.5 year (September 2009–March 2014) time-series of remotely-sensed data of altimeter significant wave heights to describe the temporal and spatial variability of ocean swells along the northern coast of the Gulf of Guinea. The NOAA WAVEWATCH III (NWW3) wave model data were used with ...

  5. Void Volume Swelling Dependent on Grain Size in Austenitic Stainless Steel

    DEFF Research Database (Denmark)

    Singh, Bachu Narain

    1973-01-01

    Describes some of the main findings of a systematic study of the effect of grain size on the void volume swelling. In this study a powder-produced 20 Ni/20 Cr austenitic stainless steel, with 0.02% carbon and without carbide-forming elements was used. Some specimens containing dispersions...

  6. On recoil energy dependent void swelling in pure copper: part 1, experimental results

    DEFF Research Database (Denmark)

    Singh, B.N.; Eldrup, M.; Horsewell, Andy

    2000-01-01

    In recent years, the problem of void swelling has been treated within the framework of production bias model (PBM). The model considers the intracascade clustering of vacancies and self-interstitial atoms (SIAs), their thermal stability and the resulting asymmetry in the production of free and mo...

  7. Activation of the TASK-2 channel after cell swelling is dependent on tyrosine phosphorylation

    DEFF Research Database (Denmark)

    Kirkegaard, Signe Skyum; Lambert, Ian Henry; Gammeltoft, Steen

    2010-01-01

    The swelling-activated K(+) currents (I(K,vol)) in Ehrlich ascites tumor cells (EATC) has been reported to be through the two-pore domain (K(2p)), TWIK-related acid-sensitive K(+) channel 2 (TASK-2). The regulatory volume decrease (RVD), following hypotonic exposure in EATC, is rate limited by I...

  8. Molecular dynamics simulations in the grand canonical ensemble: Application to clay mineral swelling

    Science.gov (United States)

    Shroll, Robert M.; Smith, David E.

    1999-11-01

    A grand canonical ensemble molecular dynamics (GMD) simulation method has been adapted to examine the thermodynamics of clay-mineral hydration. In the GMD method, the number of water molecules in the system is treated as a continuous variable for which an equation of motion is established. Fluctuations in the water content at constant chemical potential are investigated using trajectories of this particle number variable. A bias potential may be used to modify the free energy contour along the particle number coordinate. This catalyzes particle fluctuations and greatly improves simulation convergence. Adaptation of the GMD method to treat hydrated clay minerals included the introduction of a local-control technique that fixes the water chemical potential in the clay interlayer region. In addition, a bias-potential feedback algorithm was implemented to improve particle fluctuation efficiency. Information pertaining to the free energy contour, generated during the course of the simulation, was used periodically to enhance the bias potential. This allowed for the utilization of a single input bias potential under a broad range of simulation conditions. The method was used to investigate swelling of a cesium-montmorillonite clay. Measured disjoining pressures showed oscillations that are indicative of crystalline-swelling phase transitions. Integration of the disjoining pressures yielded a swelling free energy profile with distinct free-energy minima for the one- and two-layer hydrates. The results may be compared qualitatively with both clay swelling and surface force apparatus experiments, and with previous simulation studies of simple fluids in slit pores.

  9. HYPOOSMOTIC SPERM SWELLING TEST DOES NOT ASSESS FERTILIZING-CAPACITY OF HUMAN SPERMATOZOA

    NARCIS (Netherlands)

    JAGER, S; KREMER, J; WIJCHMAN, J

    1991-01-01

    The hypo-osmotic sperm swelling (HOSS) test was performed on semen samples of five normospermic men from couples with prolonged infertility. Previously, the men had negative results of the zona-free hamster oocyte (ZFHO) test on two different ejaculates and the wives subsequently had become pregnant

  10. A purple swelling on the tongue | Panta | Pan African Medical Journal

    African Journals Online (AJOL)

    Hemangiomas are benign hamartomatous lesions that are slow growing, sessile or pedunculated, smooth or lobulated, red swellings which sometimes exhibit a bluish hue. Hemangiomas of the tongue need special attention due to their susceptability to trauma from masticatory forces. Pan African Medical Journal 2015; 21 ...

  11. Sea and swell along west coast of India: Study based on measured data

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; AshokKumar, K.; Pednekar, P.; Gowthaman, R.

    Separation of sea and swell from the measured data is important for studying the wind wave dynamics and in the design of coastal and offshore structures. The wave data collected using Datawell directional waverider buoy at a deep-water location...

  12. Effect of a foot pump device on lower leg swelling in physically ...

    African Journals Online (AJOL)

    The aim of the study was to examine the effect of using a foot pump device (FPD) on orthostatic lower leg swelling in physically inactive office workers. Thirty-four physically inactive office workers (age: 41.6 ± 8.9 years, 26 females, 8 males) volunteered for the study. They participated in two exercise days (day 1 and 2), ...

  13. Permeability and selectivity of reverse osmosis membranes: correlation to swelling revisited.

    Science.gov (United States)

    Dražević, Emil; Košutić, Krešimir; Freger, Viatcheslav

    2014-02-01

    Membrane swelling governs both rejection of solutes and permeability of polymeric membranes, however very few data have been available on swelling in water of salt-rejecting reverse osmosis (RO) membranes. This study assesses swelling, thickness and their relation to water permeability for four commercial polyamide (PA) RO membranes (SWC4+, ESPA1, XLE and BW30) using atomic force microscopy (AFM) and attenuated total reflection Fourier transform IR spectroscopy (ATR-FTIR). ATR-FTIR offered a significantly improved estimate of the actual barrier thickness of PA, given AFM is biased by porosity ("fluffy parts") or wiggling of the active layer or presence of a coating layer. Thus obtained intrinsic permeability (permeability times thickness) and selectivity of aromatic polyamides plotted versus swelling falls well on a general trend, along with previously reported data on several common materials showing RO and NF selectivity. The observed general trend may be rationalized by viewing the polymers as a random composite medium containing molecularly small pores. The results suggest that the combination of a rigid low dielectric matrix, limiting the pore size, with multiple hydrophilic H-bonding sites may be a common feature of RO/NF membranes, allowing both high permeability and selectivity. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  14. Thermal Expansion and Swelling of Cured Epoxy Resin Used in Graphite/Epoxy Composite

    Science.gov (United States)

    Adamson, M. J.

    1979-01-01

    The thermal expansion and swelling of resin material as influenced by variations in temperature during moisture absorption is discussed. Comparison measurements using composites constructed of graphite fibers and each of two epoxy resin matrices are included. Polymer theory relative to these findings is discussed and modifications are proposed.

  15. Reactive transport modeling to quantify swelling of clay-sulfate rocks

    Science.gov (United States)

    Schweizer, Daniel; Prommer, Henning; Blum, Philipp; Siade, Adam J.; Butscher, Christoph

    2017-04-01

    The processes underlying the swelling of clay-sulfate rocks are complex and have been the subject of numerous previous investigations. In general, the transformation of anhydrite into gypsum, which is accompanied by a volume increase of 61 %, is considered the main mechanism of swelling. The process is typically initiated by a change in hydraulic conditions, followed by influx of water and a change in geochemistry. However, hydraulic and geochemical changes in the swelling zone, which may be induced by construction measures and borehole drillings, remain difficult to assess. In this study, a numerical reactive transport model was developed for a study site in SW-Germany, where geothermal drillings led to significant swelling in clay-sulfate rocks, heaves at the ground surface and large damage of houses. A dual-domain reactive transport modeling approach was employed to investigate and quantify the importance of groundwater influx and geochemical reactions within the swelling zone. The observed swelling process was conceptualized through (i) a mobile domain that accounts for water flux and solute transport along preferential flow paths (PFP); and (ii) an immobile 'reactive' domain considering the rate-limited transformation of anhydrite into gypsum. The model was calibrated by optimizing adjustable model parameters until the calculated volume changes that result from the simulated transformation of anhydrite into gypsum agreed with geodesic heave measurements at the ground surface. The calibrated model is capable of closely replicating the heave measurements that were taken prior to the mitigation measures that were implemented at the site. The reaction rate constants for anhydrite dissolution and gypsum precipitation that were determined during the model calibration were, not unexpectedly, lower than the corresponding constants reported from laboratory experiments. It was found that transport by PFP as well as the mass transfer between the mobile and immobile

  16. Loss of knee-extension strength is related to knee swelling after total knee arthroplasty.

    Science.gov (United States)

    Holm, Bente; Kristensen, Morten T; Bencke, Jesper; Husted, Henrik; Kehlet, Henrik; Bandholm, Thomas

    2010-11-01

    To examine whether changes in knee-extension strength and functional performance are related to knee swelling after total knee arthroplasty (TKA). Prospective, descriptive, hypothesis-generating study. A fast-track orthopedic arthroplasty unit at a university hospital. Patients (N=24; mean age, 66y; 13 women) scheduled for primary unilateral TKA were investigated 1 week before surgery and on the day of hospital discharge 2.4 days postsurgery. Not applicable. We assessed all patients for knee-joint circumference, knee-extension strength, and functional performance using the Timed Up & Go, 30-second Chair Stand, and 10-m fast speed walking tests, together with knee pain during all active test procedures. All investigated variables changed significantly from pre- to postsurgery independent of knee pain. Importantly, knee circumference increased (knee swelling) and correlated significantly with the decrease in knee-extension strength (r=-.51; P=.01). Reduced fast-speed walking correlated significantly with decreased knee-extension strength (r=.59; P=.003) and decreased knee flexion (r=.52; P=.011). Multiple linear regression showed that knee swelling (P=.023), adjusted for age and sex, could explain 27% of the decrease in knee-extension strength. Another model showed that changes in knee-extension strength (P=.009) and knee flexion (P=.018) were associated independently with decreased performance in fast-speed walking, explaining 57% of the variation in fast-speed walking. Our results indicate that the well-known finding of decreased knee-extension strength, which decreases functional performance shortly after TKA, is caused in part by postoperative knee swelling. Future studies may look at specific interventions aimed at decreasing knee swelling postsurgery to preserve knee-extension strength and facilitate physical rehabilitation after TKA. Copyright © 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  17. Influence of kinesiologic tape on postoperative swelling, pain and trismus after zygomatico-orbital fractures.

    Science.gov (United States)

    Ristow, Oliver; Pautke, Christoph; Victoria Kehl; Koerdt, Steffen; Schwärzler, Katharina; Hahnefeld, Lilian; Hohlweg-Majert, Bettina

    2014-07-01

    Surgical treatment of zygomatico-orbital (ZO) fractures is a common procedure in maxillofacial surgery. Often accompanied by pain, trismus and swelling, postoperative morbidity is a major disadvantage, affecting patients' quality of life. The appliance of kinesiologic tape (KT) improves the blood and lymph flow, removing congestions of lymphatic fluid and haemorrhages. The aim of this study was to find out if the application of kinesiologic tape prevents or improves swelling, pain and trismus after zygomatico-orbital fracture surgery, improving patients' postoperative quality of life. A total of 30 patients were assigned for treatment of zygomatico-orbital fractures and were randomly divided into treatment either with or without kinesiologic tape. Tape was applied directly after surgery and maintained for at least 5 days postoperatively. Facial swelling was quantified using a five-line measurement at six specific time points. Pain and degree of mouth opening was measured. Patient's subjective feeling and satisfaction was queried. The results of this study show that application of kinesiologic tape after zygomatico-orbital surgery significantly reduced the incidence of swelling with an earlier swelling maximum, and decreased the maximum turgidity for more than 60% during the first 2 days after surgery. Although, kinesiologic tape has no significant influence on pain control and trismus, mouth opening increased earlier after operation in the kinesiologic tape group compared to the no-kinesiologic tape group. Furthermore, patients with kinesiologic tape felt significantly lower morbidity than those without kinesiologic tape. Therefore kinesiologic tape is a promising, simple, less traumatic, economical approach, which is free from adverse reaction and improves patients' quality of life. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  18. Swelling-activated Ca2+ channels trigger Ca2+ signals in Merkel cells.

    Directory of Open Access Journals (Sweden)

    Henry Haeberle

    2008-03-01

    Full Text Available Merkel cell-neurite complexes are highly sensitive touch receptors comprising epidermal Merkel cells and sensory afferents. Based on morphological and molecular studies, Merkel cells are proposed to be mechanosensory cells that signal afferents via neurotransmission; however, functional studies testing this hypothesis in intact skin have produced conflicting results. To test this model in a simplified system, we asked whether purified Merkel cells are directly activated by mechanical stimulation. Cell shape was manipulated with anisotonic solution changes and responses were monitored by Ca2+ imaging with fura-2. We found that hypotonic-induced cell swelling, but not hypertonic solutions, triggered cytoplasmic Ca2+ transients. Several lines of evidence indicate that these signals arise from swelling-activated Ca2+-permeable ion channels. First, transients were reversibly abolished by chelating extracellular Ca2+, demonstrating a requirement for Ca2+ influx across the plasma membrane. Second, Ca2+ transients were initially observed near the plasma membrane in cytoplasmic processes. Third, voltage-activated Ca2+ channel (VACC antagonists reduced transients by half, suggesting that swelling-activated channels depolarize plasma membranes to activate VACCs. Finally, emptying internal Ca2+ stores attenuated transients by 80%, suggesting Ca2+ release from stores augments swelling-activated Ca2+ signals. To identify candidate mechanotransduction channels, we used RT-PCR to amplify ion-channel transcripts whose pharmacological profiles matched those of hypotonic-evoked Ca2+ signals in Merkel cells. We found 11 amplicons, including PKD1, PKD2, and TRPC1, channels previously implicated in mechanotransduction in other cells. Collectively, these results directly demonstrate that Merkel cells are activated by hypotonic-evoked swelling, identify cellular signaling mechanisms that mediate these responses, and support the hypothesis that Merkel cells contribute

  19. Bioimpedance spectroscopy for swelling evaluation following total knee arthroplasty: a validation study.

    Science.gov (United States)

    Pichonnaz, Claude; Bassin, Jean-Philippe; Lécureux, Estelle; Currat, Damien; Jolles, Brigitte M

    2015-04-25

    The evaluation of swelling is important for the outcome of total knee arthroplasty (TKA) surgery. The circumference or volume measurements are applicable at the bedside of the patient but are altered by muscular atrophy and the post-surgical dressing. Bioimpedance spectroscopy might overcome these limitations; however, it should be validated. This study aimed to explore the validity, the reliability and the responsiveness of bioimpedance spectroscopy for measuring swelling after TKA. The degree of swelling in 25 patients undergoing TKA surgery was measured using bioimpedance spectroscopy (BIS R0), knee circumference and limb volume. The measurements were performed on D-1 (day before surgery), D + 2 (2 days after surgery) and D + 8 (8 days after surgery). The BIS R0 measurements were repeated twice, alternating between two evaluators. The percentage of the difference between the limbs was calculated for BIS R0, circumference and volume. The intra- and inter-observer intraclass correlation coefficients (ICCs), limits of agreement (LOA), effect size (Cohen's d), correlations between the methods and diagnostic sensitivity were calculated. BIS R0, circumference and volume detected swelling Bioimpedance is a valid method for the evaluation of swelling following TKA. BIS R0 also demonstrated excellent intra- and inter-evaluator reliability. The diagnostic sensitivity and responsiveness is superior to that of concurrent methods. BIS R0 is an efficient method for post-surgical follow up at the bedside of the patient. The measurement of BIS R0 is a straightforward, valid, reliable and responsive method for lower limb swelling following TKA surgery that could be used in clinics and research. ClinicalTrials.gov Identifier: NCT00627770.

  20. Starch-free grewia gum matrices: Compaction, swelling, erosion and drug release behaviour.

    Science.gov (United States)

    Nep, E I; Asare-Addo, K; Ghori, M U; Conway, B R; Smith, A M

    2015-12-30

    Polysaccharides are suitable for application as hydrophilic matrices because of their ability to hydrate and swell upon contact with fluids, forming a gel layer which controls drug release. When extracted from plants, polysaccharides often contain significant quantities of starch that impacts upon their functional properties. This study aimed to evaluate differences in swelling, erosion and drug release from matrix tablets prepared from grewia gum (GG) and starch-free grewia gum (GDS) extracted from the stems of Grewia mollis. HPMC was used as a control polymer with theophylline as a model drug. Swelling, erosion, and in-vitro release were performed in deionized water, pH 1.2 and pH 6.8 media. The Vergnaud and Krosmeyer-Peppas model were used for swelling and drug release kinetics, respectively. However, linear regression technique was used to determine the erosion rate. GDS compacts were significantly harder than the native GG and HPMC compacts. GDS matrices exhibited the fastest erosion and drug release in deionised water and phosphate buffer compared with the GG and HPMC. At pH 1.2, GDS exhibited greater swelling than erosion, and drug release was similar to GG and HPMC. This highlights the potential of GDS as a matrix for controlled release similar to HPMC and GG at pH 1.2 but with a more rapid release at pH 6.8. GDS may have wider application in reinforcing compacts with relatively low mechanical strength. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. IRRADIATION CREEP AND SWELLING OF RUSSIAN FERRITIC-MARTENSITIC STEELS IRRADIATED TO VERY HIGH EXPOSURES IN THE BN-350 FAST REACTOR AT 305-335 DEGREES C

    Energy Technology Data Exchange (ETDEWEB)

    Konobeev, Yu V.; Dvoraishin, A. M.; Porollo, S. I.; Shulepin, S. V.; Budylkin, N. I.; Mironova, E. G.; Garner, Francis A.; Toloczko, Mychailo B.

    2003-09-03

    Russian ferritic martensitic (F(slash)M) steels EP(dash)450, EP(dash)852 and EP(dash)823 were irradiated in the BN(dash)350 fast reactor in the form of gas-pressurized creep tubes. The first steel is used in Russia for hexagonal wrappers in fast reactors. The other steels were developed for compatibility with Pb(dash)Bi coolants and serve to enhance our understanding of the general behavior of this class of steels. In an earlier paper we published data on irradiation creep of EP(dash)450 and EP(dash) 823 at temperatures between 390 and 520 degrees C, with dpa levels ranging from 20 to 60 dpa. In the current paper new data on the irradiation creep and swelling of EP(dash)450 and EP(dash)852 at temperatures between 305 and 335 degrees C and doses ranging from 61 to 89 dpa are presented. Where comparisons are possible, it appears that these steels exhibit behavior that is very consistent with that of Western steels. Swelling is relatively low at high neutron exposure and confined to temperatures less then 420 degrees C, but may be camouflaged somewhat by precipitation related densification. These irradiation creep studies confirm that the creep compliance of F(slash)M steels is about one half that of austenitic steels.

  2. Mathematical modelling and numerical solution of swelling of cartilaginous tissues. Part II: Mixed-hybrid finite element solution

    NARCIS (Netherlands)

    Malakpoor, K.; Kaasschieter, E.F.; Huyghe, J.M.

    2007-01-01

    Abstract: The swelling and shrinkage of biological tissues are modelled by a four-component mixture theory [J.M. Huyghe and J.D. Janssen, Int. J. Engng. Sci. 35 (1997) 793-802; K. Malakpoor, E.F. Kaasschieter and J.M. Huyghe, Mathematical modelling and numerical solution of swelling of cartilaginous

  3. Stepwise Swelling of a Thin Film of Lamellae-Forming Poly(styrene-b-butadiene) in Cyclohexane Vapor

    DEFF Research Database (Denmark)

    Di, Zhenyu; Posselt, Dorthe; Smilgies, Detlef-M.

    2012-01-01

    We investigated the swelling of a thin film of lamellae-forming poly(styrene-b-butadiene) in cyclohexane vapor. The vapor pressure and thus the degree of swelling of the film are increased in a stepwise manner using a custom-built sample cell. The resulting structural changes during and after eac...

  4. Contribution to swelling analysis in ceramic nuclear fuels; Contribucion al analisis del hinchamiento de combustibles nucleares ceramicos

    Energy Technology Data Exchange (ETDEWEB)

    Moreno Gonzalez, A.

    1976-07-01

    In this work a swelling phenomenological model containing several experimental observation is presented. Observations such as dissolution and redi solution of gas atoms, bubble nucleations in defects, dislocations and grain boundary, bubbles migration and coalescence are included. The model gives a bubbles distribution according to their size and position the swelling rate is calculated through the bubble distribution changes. (Author) 17 refs.

  5. Competition between adsorption-induced swelling and elastic compression of coal at CO2 pressures up to 100 MPa

    NARCIS (Netherlands)

    Hol, S.; Spiers, C.J.

    2012-01-01

    Enhanced Coalbed Methane production (ECBM) by CO2 injection frequently proves ineffective due to rapidly decreasing injectivity. Adsorption-induced swelling of the coal matrix has been identified as the principal factor controlling this reduction. To improve understanding of coal swelling in

  6. Diminished swelling of cross-linked aromatic oligoamide surfaces revealing a new fouling mechanism of reverse-osmosis membranes.

    Science.gov (United States)

    Ying, Wang; Kumar, Rajender; Herzberg, Moshe; Kasher, Roni

    2015-06-02

    Swelling of the active layer of reverse osmosis (RO) membranes has an important effect on permeate water flux. The effects of organic- and biofouling on the swelling of the RO membrane active layer and the consequent changes of permeate flux are examined here. A cross-linked aromatic oligoamide film that mimics the surface chemistry of an RO polyamide membrane was synthesized stepwise on gold-coated surfaces. Foulant adsorption to the oligoamide film and its swelling were measured with a quartz crystal microbalance, and the effects of fouling on the membrane's performance were evaluated. The foulants were extracellular polymeric substances (EPS) extracted from fouled RO membranes and organic compounds of ultrafiltration permeate (UFP) from a membrane bioreactor used to treat municipal wastewater. The adsorbed foulants affected the swelling of the cross-linked oligoamide film differently. EPS had little effect on the swelling of the oligoamide film, whereas UFP significantly impaired swelling. Permeate flux declined more rapidly under UFP fouling than it did under EPS. Foulant adsorption was shown to diminish swelling of the aromatic oligoamide surfaces. Among the already known RO membrane fouling mechanisms, a novel RO fouling mechanism is proposed, in which foulant-membrane interactions hinder membrane swelling and thus increase hydraulic resistance.

  7. Effect of grain morphology on gas bubble swelling in UMo fuels – A 3D microstructure dependent Booth model

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Shenyang; Burkes, Douglas; Lavender, Curt A.; Joshi, Vineet

    2016-11-01

    A three dimensional microstructure dependent swelling model is developed for studying the fission gas swelling kinetics in irradiated nuclear fuels. The model is extended from the Booth model [1] in order to investigate the effect of heterogeneous microstructures on gas bubble swelling kinetics. As an application of the model, the effect of grain morphology, fission gas diffusivity, and spatial dependent fission rate on swelling kinetics are simulated in UMo fuels. It is found that the decrease of grain size, the increase of grain aspect ratio for the grain having the same volume, and the increase of fission gas diffusivity (fission rate) cause the increase of swelling kinetics. Other heterogeneities such as second phases and spatial dependent thermodynamic properties including diffusivity of fission gas, sink and source strength of defects could be naturally integrated into the model to enhance the model capability.

  8. Effect of grain morphology on gas bubble swelling in UMo fuels – A 3D microstructure dependent Booth model

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Shenyang, E-mail: shenyang.hu@pnnl.gov; Burkes, Douglas; Lavender, Curt A.; Joshi, Vineet

    2016-11-15

    A three dimensional microstructure dependent swelling model is developed for studying the fission gas swelling kinetics in irradiated nuclear fuels. The model is extended from the Booth model [1] in order to investigate the effect of heterogeneous microstructures on gas bubble swelling kinetics. As an application of the model, the effect of grain morphology, fission gas diffusivity, and spatially dependent fission rate on swelling kinetics are simulated in UMo fuels. It is found that the decrease of grain size, the increase of grain aspect ratio for the grain having the same volume, and the increase of fission gas diffusivity (fission rate) cause the increase of swelling kinetics. Other heterogeneities such as second phases and spatially dependent thermodynamic properties including diffusivity of fission gas, sink and source strength of defects could be naturally integrated into the model to enhance the model capability.

  9. Dual-energy synchrotron X ray measurements of rapid soil density and water content changes in swelling soils during infiltration

    Science.gov (United States)

    Garnier, Patricia; Angulo-Jaramillo, Rafael; DiCarlo, David A.; Bauters, Tim W. J.; Darnault, Christophe J. G.; Steenhuis, Tammo S.; Parlange, J.-Yves; Baveye, Philippe

    1998-11-01

    Understanding soil swelling is hampered by the difficulty of simultaneously measuring water content and bulk density. A number of studies have used dual-energy gamma rays to investigate soil swelling. The long counting time of this technique makes it impracticable for studying the rapid changes in moisture content and soil swelling shortly after infiltration is initiated. In this paper, we use the dual-energy synchrotron X ray to measure, for the first time, the water content and bulk density changes during the fast, initial phase of the swelling process. Ponded infiltration experiments were performed with two soils: a bentonite-sand mixture and a vertisol. Swelling curves and hydraulic diffusivity were determined. Deformation was very rapid immediately after water application and then became progressively slower. The hydraulic diffusivity decreased with time, which can partially explain the very rapid decrease in infiltration rates observed in the field.

  10. A Plasma Based Beam Combiner for Very High Fluence and Energy

    Science.gov (United States)

    Kirkwood, Robert

    2017-10-01

    Recent work at NIF has demonstrated a plasma-based optic that combines the energy and fluence of many laser beams into a single bright beam, thus creating a new technique for designing future high energy density physics experiments. The technique uses the Cross Beam Energy Transfer (CBET) process and shows for the first time that a plasma can combine beams to produce a single beam that emerges with energy and fluence beyond that of any of those input for delivery to a range of experimental targets. In an initial demonstration multiple beams of the National Ignition Facility (NIF) laser have been combined in a plasma to produce a directed pulse of light with 4 +1 kJ of energy in its 1 ns duration which is 3.6 times the energy and 3.2 times the fluence of any of the incident beams during that period and is NIFs brightest 1ns duration beam of UV light. These enhancements are due to the non-linear interaction of the beams with a self-generated plasma diffractive optic which is far more damage resistant than existing solid state optics, and is inherently capable of producing much higher single beam fluence and radiance than solid state refractive or reflective optics can. The initial results are presently being used to further validate models of CBET which predict a larger number of non-resonant pump beams will scale up outputs still further. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  11. A Project for High Fluence 14 MeV Neutron Source

    CERN Document Server

    Pillon, Mario; Pizzuto, Aldo; Pietropaolo, Antonino

    2014-01-01

    The international community agrees on the importance to build a large facility devoted to test and validate materials to be used in harsh neutron environments. Such a facility, proposed by ENEA , reconsiders a previous study known as “Sorgentina” but takes into account new technological development so far attained. The “New Sorgentina” Fusion Source (NSFS) project is based upon an intense D - T 14 MeV neutron source achievable with T and D ion beams impinging on 2 m radius rotating target s . NSFS produces about 1 x10 13 n cm - 2 s - 1 over about 50 cm 3 . The NSFS facility will use the ion source and accelerating system technology developed for the Positive Ion Injectors (PII) used to heat the plasma in the fusion experiments,. NSFS, to be intended as an European facility, may be realized in a few years, once provided a preliminary technological program devote to study the operation of the ion source in continuous mode, target h eat loading/ removal, target and tritium handling, inventory as well as ...

  12. Effects of ATR-2 Irradiation to High Fluence on Nine RPV Surveillance Materials

    Energy Technology Data Exchange (ETDEWEB)

    Nanstad, Randy K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Odette, George R. [Univ. of California, Santa Barbara, CA (United States); Almirall, Nathan [Univ. of California, Santa Barbara, CA (United States); Robertson, Janet [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Server, W. L. [ATI Consulting, Pinehurst, NC (United States); Yamamoto, T. [Univ. of California, Santa Barbara, CA (United States); Wells, Peter [Univ. of California, Santa Barbara, CA (United States)

    2017-05-01

    The reactor pressure vessel (RPV) in a light-water reactor (LWR) represents the first line of defense against a release of radiation in case of an accident. Thus, regulations that govern the operation of commercial nuclear power plants require conservative margins of fracture toughness, both during normal operation and under accident scenarios. In the unirradiated condition, the RPV has sufficient fracture toughness such that failure is implausible under any postulated condition, including pressurized thermal shock (PTS) in pressurized water reactors (PWR). In the irradiated condition, however, the fracture toughness of the RPV may be severely degraded, with the degree of toughness loss dependent on the radiation sensitivity of the materials. The available embrittlement predictive models and our present understanding of radiation damage are not fully quantitative, and do not treat all potentially significant variables and issues, particularly considering extension of operation to 80y.

  13. Retention of nanocrystalline WN{sub x} layers exposed to high-fluence deuterium plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Vassallo, E., E-mail: vassallo@ifp.cnr.it [CNR, Istituto di Fisica del Plasma “ P. Caldirola ”, 20125 Milano (Italy); Caniello, R., E-mail: caniello@ifp.cnr.it [CNR, Istituto di Fisica del Plasma “ P. Caldirola ”, 20125 Milano (Italy); Angella, G., E-mail: angella@ieni.cnr.it [CNR, Istituto per l’Energetica e le Interfasi, 20125 Milano (Italy); Dellasega, D., E-mail: david.dellasega@polimi.it [CNR, Istituto di Fisica del Plasma “ P. Caldirola ”, 20125 Milano (Italy); Politecnico di Milano, Dipartimento di Energia, 20156 Milano (Italy); Granucci, G., E-mail: granucci@ifp.cnr.it [CNR, Istituto di Fisica del Plasma “ P. Caldirola ”, 20125 Milano (Italy); Mellera, V., E-mail: mellera@ifp.cnr.it [CNR, Istituto di Fisica del Plasma “ P. Caldirola ”, 20125 Milano (Italy); Minelli, D., E-mail: minelli@ifp.cnr.it [CNR, Istituto di Fisica del Plasma “ P. Caldirola ”, 20125 Milano (Italy); Pedroni, M., E-mail: pedroni@ifp.cnr.it [CNR, Istituto di Fisica del Plasma “ P. Caldirola ”, 20125 Milano (Italy); Ricci, D., E-mail: ricci@ifp.cnr.it [CNR, Istituto di Fisica del Plasma “ P. Caldirola ”, 20125 Milano (Italy); Rigato, V., E-mail: valentino.rigato@lnl.infn.it [INFN – Laboratori Nazionali di Legnaro, Legnaro, 35020 Padova (Italy); and others

    2015-11-15

    For high-power plasma operation regimes in tokamak fusion devices the power load onto W divertor plates must be kept below acceptable limits for materials. N{sub 2} gas is likely to be used to reduce the power load. However, because of erosion phenomena, WN{sub x} compounds will be produced in the divertor and tritium retention is issue of concern. We report recent experiments using the GYM linear plasma device that examined D retention in WN{sub x} compounds exposed to D plasma at divertor relevant fluence (∼10{sup 24} m{sup −2}). It is shown that WN{sub x} compounds with different nitrogen concentration have very similar D retention, lower than the case of the tungsten without nitrogen and in any case lower than the acceptable limit for operation in ITER. - Highlights: • Nitrogen in the process of tungsten redeposition in tokamak plays a very important role for fuel retention. • Incorporation of nitrogen in tungsten decreases the D retention. • WN{sub x} compounds showed a level of D retention lower than the acceptable limit for tritium (T) operation in ITER.

  14. High fluence neutron radiation of plastic scintillators for the TileCal of the ATLAS detector.

    Science.gov (United States)

    Mdhluli, J. E.; Davydov, Yu I.; Baranov, V.; Mthembu, S.; Erasmus, R.; Jivan, H.; Khanye, N.; Tlou, H.; Tjale, B.; Starchenko, J.; Solovyanov, O.; Mellado, B.; Sideras-Haddad, E.

    2017-09-01

    We report on structural and optical properties of neutron irradiated plastic scintillators. These scintillators were subjected to a neutron beam with wide energy range of up to 10MeV and a neutron flux range of 1.2 × 1012 - 9.4 × 1012 n/cm 2 using the IBR-2 pulsed reactor at the Joint Institute for Nuclear Research in Dubna. A study between polyvinyl toluene based commercial scintillators EJ200, EJ208 and EJ260 as well as polystyrene based scintillator from Kharkov is conducted. Light transmission, Raman spectroscopy, fluorescence spectroscopy and light yield testing was performed to characterize the damage induced in the samples. Preliminary results from the tests performed indicate no change in the optical and structural properties of the scintillators. The polystyrene based scintillators were further subjected to a higher neutron flux range of 3.8 × 1012 - 1.8 × 1014 n/cm 2 using the IBR-2 pulsed reactor.

  15. Temperature and high fluence induced ripple rotation on Si(100) surface

    Science.gov (United States)

    Chowdhury, Debasree; Satpati, Biswarup; Ghose, Debabrata

    2016-12-01

    The topography evolution of Si(100) surface due to oblique incidence low energy ion beam sputtering (IBS) is investigated. Experiments were carried out at different elevated temperatures from 20 °C-450 °C and at each temperature, the ion fluence is systematically varied in a wide range from 1 × 1018 cm-2 to 1 × 1020 cm-2. The ion sputtered surface morphologies are characterized by atomic force microscopy and high-resolution cross-sectional transmission electron microscopy. At room temperature, the ion sputtered surfaces show periodic ripple nanopatterns where their wave-vector remains parallel to ion beam projection for the entire fluence range. With an increase of substrate temperature, these patterns tend to demolish and reduce into randomly ordered mound-like structures around 350 °C. A further rise in temperature above 400 °C leads orthogonally rotated ripples beyond fluence 5 × 1019 cm-2. All the results are discussed combining the theoretical framework of linear, non-linear and recently developed mass redistribution continuum models of pattern formation by IBS. These results have technological importance regarding the control over ion-induced pattern formation, as well providing useful information for further progress in the theoretical field.

  16. Corneal Swelling with Cosmetic etafilcon A Lenses versus No Lens Wear

    Science.gov (United States)

    Moezzi, Amir M.; Varikooty, Jalaiah; Schulze, Marc; Ngo, William; Lorenz, Kathrine Osborn; Boree, Danielle; Jones, Lyndon W.

    2016-01-01

    ABSTRACT Purpose To determine if the use of pigments or adding polyvinyl pyrrolidone during the fabrication of 1-DAY ACUVUE DEFINE (AD) brand contact lenses impacts open-eye corneal swelling compared with no lens wear (NLW). Methods A partial double-masked, randomized, bilateral crossover study was conducted in 24 Asian subjects using AD, 1-DAY ACUVUE DEFINE with Lacreon (ADL), NLW, and a control lens with no tint (1-DAY ACUVUE MOIST [AM]). Central corneal thickness was measured before insertion and immediately after removal after 8 ± 1 h of open-eye wear using an optical pachymeter in one eye. Corneal thickness along a 10-mm cord was measured in the contralateral eye using the Visante optical coherence tomographer (OCT). Corneal swelling was tested for noninferiority using a 5% margin. The endothelial bleb response was measured at baseline and 20 min after lens insertion using specular microscopy. Subjective grading of corneal staining and limbal/bulbar hyperemia were also monitored. Results After 8 ± 1 h of open-eye wear, central corneal swelling across the study lenses with either optical pachymeter or OCT methods was negligible. Peripheral corneal swelling least-square mean differences with OCT were −0.03% (95% confidence interval [95% CI], −0.65 to 0.58%) and −0.26% (95% CI, −0.87 to 0.36%) between AD and ADL and the control lens (AM), respectively, and 1.67% (95% CI, 1.06 to 2.29%) and 1.45% (95% CI, 0.84 to 2.06%) between AD and ADL and NLW, respectively. No endothelial blebs were observed. No clinically significant differences were distinguished between the lenses and NLW for corneal staining and limbal/bulbar hyperemia. Conclusions After 8 ± 1 h of open-eye wear, central and peripheral corneal swelling along the horizontal meridian with AD, ADL, AM, and NLW were equivalent. These results confirm that the addition of polyvinyl pyrrolidone or pigments to etafilcon A to obtain a limbal ring design have no impact on corneal swelling or limbal

  17. Controlling the extrudate swell in melt extrusion additive manufacturing of 3D scaffolds: a designed experiment.

    Science.gov (United States)

    Yousefi, Azizeh-Mitra; Smucker, Byran; Naber, Alex; Wyrick, Cara; Shaw, Charles; Bennett, Katelyn; Szekely, Sarah; Focke, Carlie; Wood, Katherine A

    2018-02-01

    Tissue engineering using three-dimensional porous scaffolds has shown promise for the restoration of normal function in injured and diseased tissues and organs. Rigorous control over scaffold architecture in melt extrusion additive manufacturing is highly restricted mainly due to pronounced variations in the deposited strand diameter upon any variations in process conditions and polymer viscoelasticity. We have designed an I-optimal, split-plot experiment to study the extrudate swell in melt extrusion additive manufacturing and to control the scaffold architecture. The designed experiment was used to generate data to relate three responses (swell, density, and modulus) to a set of controllable factors (plotting needle diameter, temperature, pressure, and the dispensing speed). The fitted regression relationships were used to optimize the three responses simultaneously. The swell response was constrained to be close to 1 while maximizing the modulus and minimizing the density. Constraining the extrudate swell to 1 generates design-driven scaffolds, with strand diameters equal to the plotting needle diameter, and allows a greater control over scaffold pore size. Hence, the modulus of the scaffolds can be fully controlled by adjusting the in-plane distance between the deposited strands. To the extent of the model's validity, we can eliminate the effect of extrudate swell in designing these scaffolds, while targeting a range of porosity and modulus appropriate for bone tissue engineering. The result of this optimization was a predicted modulus of 14 MPa and a predicted density of 0.29 g/cm 3 (porosity ≈ 75%) using polycaprolactone as scaffold material. These predicted responses corresponded to factor levels of 0.6 μm for the plotting needle diameter, plotting pressure of 2.5 bar, melt temperature of 113.5 °C, and dispensing speed of 2 mm/s. The validation scaffold enabled us to quantify the percentage difference for the predictions, which was 9.5% for the

  18. Facial Swelling

    Science.gov (United States)

    ... forehead or face?YesNoDo you have red, flaky, oily areas near your scalp, in the folds of ... SEBACEOUS CYST, a collection of oil under the skin. Sebaceous cysts are usually small and grow slowly. ...

  19. Impetigo presenting as an acute necrotizing swelling of the lower lip in an adult patient.

    Science.gov (United States)

    Ghafoor, Mohammed; Halsnad, Moorthy; Fowell, Christopher; Millar, Brian G

    2012-06-01

    The authors present an unusual case of an acute swelling of the lower lip and septicemia in a 35-year-old, recent immigrant male arriving from India. The patient presented in our emergency department with a 48-hour history of a worsening, painful swelling of the lower lip. On presentation, he was pyrexial and the lip was found to be acutely inflamed with honey-colored crusting, pustular lesions, and induration . A diagnosis of impetigo leading to necrosis of the lip was established, a rare phenomenon potentially resulting in significant tissue destruction. Appropriate medical management achieved a good outcome and prevented disabling tissue loss of the orofacial region. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Stem drive oil recovery method utilizing a downhole steam generator and anti clay-swelling agent

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, D. N.; Snavely, E. S.

    1985-06-11

    Viscous oil is recovered from a subterranean, viscous oil-containing formation by a steam flooding technique wherein steam is generated in a downhole steam generator located in an injection well by spontaneous combustion of a pressurized mixture of a water-soluble fuel such as sugars and alcohols dissolved in water or a stable hydrocarbon fuel-in-water emulsion containing an anti clay-swelling agent and substantially pure oxygen. The generated mixture of steam and combustion gases pass through the formation, displacing oil and reducing the oil's viscosity and the mobilized oil is produced from the formation via a spaced-apart production well. Suitable anti clay-swelling agents include metal halide salts and diammonium phosphate.

  1. Hydrogel-swelling driven delivery device for corrosion resistance of metal in water.

    Science.gov (United States)

    Gu, Yu; Yang, Li-Ming; Chen, Jie; Wang, Ling-Ling; Chen, Bin

    2015-01-01

    Corrosion on steel and copper pipes in industry can trigger pollution and weakness due to undesired chemical and biochemical reactions. Too much or too little inhibitor can decrease its efficiency, even causing waste and pollution. In this contribution, an innovative delivery device driven by hydrogel swelling, mainly consisting of a semi-permeable membrane, a hydrogel-swelling force drive and a release orifice, was developed to control the release of inhibitor in a water system at a constant rate, leading the amount of inhibitor to maintain a proper concentration. The effects of hydrogel mass and orifice dimension on release property were studied for controlling release rate. Moreover, a weight loss experiment on carbon steels was carried out to show the incredible anti-corrosion function of the system.

  2. Porous Polyelectrolyte Hydrogels With Enhanced Swelling Properties Prepared Via Thermal Reverse Casting Technique

    Science.gov (United States)

    Salerno, Aurelio; Netti, Paolo A.

    2010-06-01

    In this work we investigated the preparation and characterization of porous polyelectrolyte hydrogels via thermal reverse casting technique. Polyacrylamide hydrogels were synthesized by free-radical crosslinking polymerization into the space of an agarose gel which, after the setting of the chemical gel, was removed to allow the formation of an interconnected porosity pathway. Two different monomer/agarose solution ratios were selected for the reverse casting process and, the resulting hydrogels characterized in terms of morphological, micro-structural and thermal properties, as well as swelling capability in solutions at different ionic strength. The results of this study demonstrated that proposed technique allowed the design of porous polyacrylamide hydrogels with well controlled pore structures. Furthermore, if compared to non porous polyacrylamide hydrogel, the as obtained hydrogels were characterized by enhanced swelling properties and that, these properties were fine tuned by the appropriate selection of the templating agent concentration.

  3. Synovial hemangiohamartoma presenting as knee pain, swelling and a soft tissue mass: a case report

    Directory of Open Access Journals (Sweden)

    Senol Serkan

    2012-07-01

    Full Text Available Abstract Introduction We present a case of a patient with juxtaarticular hemangiohamartoma with a synovial extension associated with hemorrhagic synovitis and recurrent spontaneous hemarthrosis. Case presentation A 21-year-old Caucasian woman was admitted to our hospital complaining of pain and swelling at her knee for 6 months. In the magnetic resonance imaging, T2-weighted and fat-suppressed scans revealed a mass with high signal intensity just posterior to the patellar tendon. We performed an excisional biopsy of the mass through an anterior longitudinal incision. Excised material included arterial and venous vascular structures, which were found to be spread among the fat, connective and peripheral nerve tissues microscopically. Conclusion Although hemangiohamartomas are not true neoplasms, they may cause knee pain, swelling and hemarthrosis that warrant surgical resection. This lesion, although rare, should be considered in the differential diagnosis, especially in teenagers and young adults.

  4. FE-SEM observation of swelled seaweed using hydrophilic ionic liquid; 1-butyl-3-methylimidazolium tetrafluoroborate.

    Science.gov (United States)

    Takahashi, Chisato; Shirai, Takashi; Fuji, Masayoshi

    2013-01-01

    The method to observe the exact morphology of swelled seaweed as an example of biological material by field emission scanning electron microscopy (FE-SEM) with the aid of hydrophilic ionic liquid (IL); 1-butyl-3-methylimidazolium tetrafluoroborate is reported. Seaweed was first swelled in 3.5% NaCl solution and then treated with the IL and water mixture in 1:7 weight ratios and centrifuged to remove the excess IL solution. Thus treated seaweed maintained its morphology even at high magnification and did not show drying in the FE-SEM chamber. This observation technique might be useful for various kinds of biological materials to be observed under FE-SEM. Copyright © 2012 Wiley Periodicals, Inc.

  5. The Goodman swell: a lithospheric flexure caused by crustal loading along the Midcontinent rift system

    Science.gov (United States)

    Peterman, Z.E.; Sims, P.K.

    1988-01-01

    Rb-Sr biotite ages of Archean and Early to Middle Proterozoic crystalline rocks in northern Wisconsin and adjacent Upper Peninsula of Michigan describe a regionally systematic pattern related to differential uplift. An "age low' occurs in northern Wisconsin where values range from 1070-1172 Ma for rocks with crystallization ages of 1760 to 1865 Ma. These values overlap with the main episode of mafic igneous activity (1090 to 1120 Ma) along the Midcontinent rift system (MRS). We interpret these low biotite ages as registering closure due to cooling below the 300??C isotherm as a consequence of uplift and rapid erosion of an area that we are informally naming the Goodman swell. We interpret the swell to be a forebulge imposed on an elastic crust by loading of mafic igneous rocks along and within the axis of the MRS. -from Authors

  6. Delayed resolution of eyelid swelling in preseptal cellulitis in a child: beware of causing occlusion amblyopia

    Science.gov (United States)

    Upendran, Muralidharan R; McLoone, Eibhlin

    2013-01-01

    A 7-month-old child presented with a 6-day history of right eyelid swelling and redness. She was being treated with chloramphenicol ointment and oral flucloxacillin by the general practitioner. Clinical examination revealed features of preseptal cellulitis. There was no evidence of orbital involvement and the child was generally well otherwise. Her oral antibiotics were changed and she was adviced to attend for a review in 2 days time. However, the child did not return for a review. Three weeks later following resolution of the eyelid swelling, the child represented with a divergent squint in the right eye. Clinical and orthoptic investigations suggested occlusion amblyopia. The child is currently receiving patching treatment for the amblyopia and is awaiting surgery for squint eye. PMID:23476010

  7. Nasal swelling due to plasma cell infiltrate in a cat without plasma cell pododermatitis.

    Science.gov (United States)

    Declercq, Jan; De Bosschere, Hendrik

    2010-08-01

    A cat with an upper respiratory infection was presented for examination. Close examination of the face revealed a firm, haired rounded swelling on the bridge of the nose. Serum protein electrophoresis demonstrated a mild hypergammaglobulinaemia. The cat tested negative for feline immunodeficiency virus. Skin biopsy of the nasal lesion revealed nodular angiocentric infiltrates in the deep dermis and subcutis. The mixed infiltrate had numerous plasma cells. Presence of calicivirus antigen could not be demonstrated within the skin lesion by immunohistochemical staining. The cat was treated for upper respiratory infection and 1 month later the nasal lesion had resolved. A firm and rounded swelling over the bridge of the nose may be a feline cutaneous plasmacytic reaction pattern. © 2010 The Authors. Journal compilation © 2010 ESVD and ACVD.

  8. Expanding Prevertebral Soft Tissue Swelling Subsequent to a Motor Vehicle Collision

    Directory of Open Access Journals (Sweden)

    Matthew F. Ryan

    2014-01-01

    Full Text Available Cervical acceleration/deceleration or whiplash injuries are a common cause of cervical spine trauma. Cervical acceleration/deceleration can result in vertebral fractures, subluxations, and ligamentous and other soft tissue injuries. Severe injuries are often evidenced by increased prevertebral swelling on lateral X-ray. Assessment of the prevertebral space on lateral cervical spine films is an essential component for identifying potential traumatic neck injuries. We describe a case in which an 84-year-old man on coumadin presented to the emergency department after a low-impact motor vehicle crash. The patient initially complained of neck and shoulder pain which subsequently progressed to hoarseness, dysphagia, and dyspnea. Imaging studies revealed significant prevertebral tissue swelling with anterior compression of his airway that required airway stabilization via awake fiber-optic intubation and reversal of his anticoagulation therapy.

  9. Mechanical, thermal and swelling properties of phosphorylated nanocellulose fibrils/PVA nanocomposite membranes.

    Science.gov (United States)

    Niazi, Muhammad Bilal Khan; Jahan, Zaib; Berg, Sigrun Sofie; Gregersen, Øyvind Weiby

    2017-12-01

    Cellulose nanofibrils (CNF) have strong reinforcing properties when incorporated in a compatible polymer matrix. This work reports the effect of the addition of phosphorylated nanocellulose (PCNF) on the mechanical, thermal and swelling properties of poly(vinyl alcohol) (PVA) nanocomposite membranes. The incorporation of nanocellulose in PVA reduced the crystallinity at 0%RH. However, when the films were exposed to higher humidities the crystallinity increased. No apparent trend is observed for mechanical properties for dry membranes (0% RH). However, at 93% RH the elastic modulus increased strongly from 0.12MPa to 0.82MPa when adding 6% PCNF. At higher humidities, the moisture uptake has large influence on storage modulus, tan δ and tensile properties. Membranes containing 1% PCNF absorbed most moisture. Swelling, thermal and mechanical properties indicate a good potential for applying of PVA/phosphorylated nanocellulose composite membranes for CO2 separation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Plasticity, Swell-Shrink, and Microstructure of Phosphogypsum Admixed Lime Stabilized Expansive Soil

    Directory of Open Access Journals (Sweden)

    Jijo James

    2016-01-01

    Full Text Available The study involved utilization of an industrial waste, Phosphogypsum (PG, as an additive to lime stabilization of an expansive soil. Three lime dosages, namely, initial consumption of lime (ICL, optimum lime content (OLC, and less than ICL (LICL, were identified for the soil under study for stabilizing the soil. Along with lime, varying doses of PG were added to the soil for stabilization. The effect of stabilization was studied by performing index tests, namely, liquid limit, plastic limit, shrinkage limit, and free swell test, on pulverized remains of failed unconfined compression test specimens. The samples were also subjected to a microstructural study by means of scanning electron microscope. Addition of PG to lime resulted in improvement in the plasticity and swell-shrink characteristics. The microstructural study revealed the formation of a dense compact mass of stabilized soil.

  11. Strategies used to inhibit postoperative swelling following removal of impacted lower third molar

    Directory of Open Access Journals (Sweden)

    Francesco Sortino

    2011-01-01

    Full Text Available Postoperative swelling following different surgical strategies is an area of great interest. The main part of literature on the topic deals with swelling after extraction of low impacted third molar. In this review, we have analyzed publications of the last 20 years with a pubmed search using the following key words: impacted third molar, swelling third molar, wisdom tooth, edema jaw, corticosteroids and extraction third molar, antibiotic prophylaxis and tooth extraction. Attention has often been focused on corticosteroid therapy administered by diverse routes (orally, IV, IM, topically and at different time schedules (before or after surgery or both. This investigation revealed how the use of different molecules and dosages makes the obtained results hardly comparable. Similar conclusions can be drawn from studies aimed at evaluating the efficacy of antibiotic therapy administered either before or after surgery. A complete review has also to take into account different surgical strategies used including various flaps, no traumatic osteothomy, and primary or secondary closure. The use of pharmacological therapy and application of an ice pack is critical in the postoperative period and has always provided positive results. However, even if it is difficult to come to definite conclusions, due to the variability of the design of studies analyzed, the postoperative discomfort identified with edema, pain and trismus following wisdom tooth removal is influenced by various factors such as the difficulty of the surgical procedure involved, age and gender of the patient, and experience of the surgeon. The pharmacological therapy when performed with corticosteroids seems to improve control of the postoperative swelling related with this kind of surgeries.

  12. How Do Organic Vapors Swell Ultra-Thin PIM-1 Films?

    KAUST Repository

    Ogieglo, Wojciech

    2017-06-22

    Dynamic sorption of ethanol and toluene vapor into ultra-thin supported PIM-1 films down to 6 nm are studied with a combination of in-situ spectroscopic ellipsometry and in-situ X-ray reflectivity. Both ethanol and toluene significantly swell the PIM-1 matrix and, at the same time, induce persistent structural relaxations of the frozen-in glassy PIM-1 morphology. For ethanol below 20 nm three effects were identified. First, the swelling magnitude at high vapor pressures is reduced by about 30% as compared to thicker films. Second, at low penetrant activities (below 0.3 p/p0) films below 20 nm are able to absorb slightly more penetrant as compared with thicker films despite similar swelling magnitude. Third, for the ultra-thin films the onset of the dynamic penetrant-induced glass transition Pg has been found to shift to higher values indicating higher resistance to plasticization. All of these effects are consistent with a view where immobilization of the super-glassy PIM-1 at the substrate surface leads to an arrested, even more rigid and plasticization-resistant, yet still very open, microporous structure. PIM-1 in contact with the larger and more condensable toluene shows very complex, heterogeneous swelling dynamics and two distinct penetrant-induced relaxation phenomena, probably associated with the film outer surface and the bulk, are detected. Following the direction of the penetrant\\'s diffusion the surface seems to plasticize earlier than the bulk and the two relaxations remain well separated down to 6 nm film thickness, where they remarkably merge to form just a single relaxation.

  13. Intrauterine Contraceptive Device Migration Presenting as Abdominal Wall Swelling: A Case Report

    Directory of Open Access Journals (Sweden)

    Imtiaz Wani

    2011-01-01

    Full Text Available A number of complications are reported with the use of intrauterine contraceptive devices. These may pursue asymptomatic course or present as an acute abdomen after migration into peritoneal cavity. The authors here are reporting an abdominal wall swelling caused by transuterine migration of a copper intrauterine contraceptive device in a 28-year-old female. An open approach was used, and impacted foreign body was retrieved.

  14. Swelling of the Upper Lip...Not always a Mucous Retention Cyst!!

    Directory of Open Access Journals (Sweden)

    Savitri M. Nerune

    2017-04-01

    Full Text Available Schwannoma, also known as neurilemmoma, is a solitary benign tumour arising from the Schwann cells. Oral schwannomas are rare and upper lip is an uncommon site. The diagnosis of schwannoma is typically made on histopathology and surgical resection is the treatment of choice. We report a case of swelling of the upper lip in a 26 year old male which was clinically diagnosed as mucous retention cyst and on histopathological examination, a diagnosis of schwannoma was offered.

  15. Re-evaluation of sarcolemma injury and muscle swelling in human skeletal muscles after eccentric exercise.

    Directory of Open Access Journals (Sweden)

    Ji-Guo Yu

    Full Text Available The results regarding the effects of unaccustomed eccentric exercise on muscle tissue are often conflicting and the aetiology of delayed onset muscle soreness (DOMS induced by eccentric exercise is still unclear. This study aimed to re-evaluate the paradigm of muscular alterations with regard to muscle sarcolemma integrity and fibre swelling in human muscles after voluntary eccentric exercise leading to DOMS. Ten young males performed eccentric exercise by downstairs running. Biopsies from the soleus muscle were obtained from 6 non-exercising controls, 4 exercised subjects within 1 hour and 6 exercised subjects at 2-3 days and 7-8 days after the exercise. Muscle fibre sarcolemma integrity, infiltration of inflammatory cells and changes in fibre size and fibre phenotype composition as well as capillary supply were examined with specific antibodies using enzyme histochemistry and immunohistochemistry. Although all exercised subjects experienced DOMS which peaked between 1.5 to 2.5 days post exercise, no significant sarcolemma injury or inflammation was detected in any post exercise group. The results do not support the prevailing hypothesis that eccentric exercise causes an initial sarcolemma injury which leads to subsequent inflammation after eccentric exercise. The fibre size was 24% larger at 7-8 days than at 2-3 days post exercise (p<0.05. In contrast, the value of capillary number per fibre area tended to decrease from 2-3 days to 7-8 days post exercise (lower in 5 of the 6 subjects at 7-8 days than at 2-3 days; p<0.05. Thus, the increased fibre size at 7-8 days post exercise was interpreted to reflect fibre swelling. Because the fibre swelling did not appear at the time that DOMS peaked (between 1.5 to 2.5 days post exercise, we concluded that fibre swelling in the soleus muscle is not directly associated with the symptom of DOMS.

  16. A solitary facial nodular swelling - A case report of intramuscular cysticercosis in buccinator muscle

    Directory of Open Access Journals (Sweden)

    Sujatha Dysanoor

    2013-06-01

    Full Text Available Taenia solium, the larvae of pork tapeworm can cause the parasitic infection known as cysticercosis. It is commonly seen in developing countries. The condition rarely involves orofacial region and represents a difficulty in clinical diagnosis. We present a case report of a healthy middle aged female patient who had a painless swelling on right side of face. The ultrasound examination revealed an intramuscular cysticercosal cyst.

  17. Observational Evidence of Summer Shamal Swells along the West Coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Glejin, J.; SanilKumar, V.; Nair, T.M.B.; Singh, J.; Mehra, P.

    are the dominant factor influencing the near shore processes. The waves along the west coast of the Indian subcontinent primarily depend on the wind conditions prevailing over the three different seasons: southwest (SW) monsoon (June-September), northeast (NE... at B2 is used to estimate the relative strength of winds between the summer Shamal and SW monsoon winds. Occurrences of summer Shamal swells at Ratnagiri depend on the comparative strengths of these wind systems. The combined effect of NW Shamal winds...

  18. Effect of Vulcanization System and Carbon Black on Mechanical and Swelling Properties of EPDM Blends

    OpenAIRE

    Mayasari, Hesty Eka; Yuniari, Arum

    2016-01-01

    EPDM (Ethylene propylene diene monomer) is one of synthetic rubber that widely used in automotive. It must be vulcanized and added by other materials before used. The aim of this study is to investigate the effect of vulcanization system and the addition of carbon black (CB) to the mechanical properties and swelling characteristic of EPDM. This research used three vulcanization system, conventional vulcanization (CV), efficient vulcanization (EV) and semi-efficient vulcanization (SEV) with th...

  19. Effect of vulcanization system and carbon black on mechanical and swelling properties of EPDM blends

    OpenAIRE

    Hesty Eka Mayasari; Arum Yuniari

    2016-01-01

    EPDM (Ethylene propylene diene monomer) is one of synthetic rubber that widely used in automotive. It must be vulcanized and added by other materials before used. The aim of this study is to investigate the effect of vulcanization system and the addition of carbon black (CB) to the mechanical properties and swelling characteristic of EPDM. This research used three vulcanization system, conventional vulcanization (CV), efficient vulcanization (EV) and semi-efficient vulcanization (SEV) with th...

  20. Advanced liquefaction using coal swelling and catalyst dispersion techniques. Quarterly progress report, July--September 1993

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, C.W. [Auburn Univ., (United States); Gutterman, C. [FWDC (United States); Chander, S. [Pennsylvania State Univ. (United States)

    1993-12-31

    The overall objective of this project is to develop a new approach for the direct liquefaction of coal to produce an all-distillate product slate at a sizable cost reduction over current technology. The approach integrates coal selection, pretreatment, coal swelling with catalyst impregnation, liquefaction, product recovery with characterization, alternate bottoms processing, and carrying out a technical assessment including an economic evaluation. The primary coal of this program, Black Thunder subbituminous coal, can be effectively beneficiated to about 3.5 wt % ash using aqueous sulfurous acid pretreatment. This treated coal can be further beneficiated to about 2 wt % ash using commercially available procedures. All three coals used in this study (Black Thunder, Burning Star bituminous, and Martin Lake lignite) are effectively swelled by a number of solvents. The most effective solvents are those having hetero-functionality. laboratory- and bench-scale liquefaction experimentation is underway using swelled and catalyst impregnated coal samples. Higher coal conversions were observed for the SO{sub 2}-treated subbituminous coal than the raw coal, regardless of catalyst type. Conversions of swelled coal were highest when Molyvan L, molybdenum naphthenate, and nickel octoate, respectively, were added to the liquefaction solvent. The study of bottoms processing consists of combining the ASCOT process which consists of coupling solvent deasphalting with delayed coking to maximize the production of coal-derived liquids while rejecting solids within the coke drum. The asphalt production phase has been completed; representative product has been evaluated. The solvent system for the deasphalting process has been established. Two ASCOT tests produced overall liquid yields (63.3 wt % and 61.5 wt %) that exceeded the combined liquid yields from the vacuum tower and ROSE process.

  1. Elimination & Mitigation of Sag & Swell Using a New UPQC-S Methodology & Fuzzy Logic Controller

    OpenAIRE

    Kanaka Raju Kalla,; Suneelgoutham Karudumpa

    2014-01-01

    This paper presents the enhancement of voltage sags, harmonic distortion and low power factor using Unified Power Quality Conditioner (UPQC) with Fuzzy Logic Controller in distribution system, The series inverter of UPQC is controlled to perform simultaneous 1) voltage sag/swell compensation and 2) load reactive power sharing with the shunt inverter. Since the series inverter simultaneously delivers active and reactive powers, this concept is named as UPQC-S (S for complex pow...

  2. Swelling of the temporal region: a case of benign masticatory muscle hypertrophy

    DEFF Research Database (Denmark)

    Gniadecka, M; Weismann, K; Herning, Gudrun Margrethe

    1997-01-01

    A 35-year-old Caucasian woman had bilateral indolent swelling of the temporal regions. Imaging studies with nuclear magnetic resonance, ultrasonography and histopathological investigation revealed enlargement of the temporal and masseter muscles, with no pathology in the skin or subcutaneous tiss....... A small prolactinoma of the pituitary gland was incidentally found. The condition, designated benign masticatory muscle hypertrophy, should be distinguished from similar diseases affecting the skin and the subcutaneous tissue of the scalp. The cause remains unknown...

  3. Study of the Effect of Swelling on Irradiation Assisted Stress Corrosion Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, Sebastien Paul [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    This report describes the methodology used to study the effect of swelling on the crack growth rate of an irradiation-assisted stress corrosion crack that is propagating in highly irradiated stainless steel 304 material irradiated to 33 dpa in the Experimental Breeder Reactor-II. The material selection, specimens design, experimental apparatus and processes are described. The results of the current test are presented.

  4. How Do Organic Vapors Swell Ultrathin Films of Polymer of Intrinsic Microporosity PIM-1?

    Science.gov (United States)

    Ogieglo, Wojciech; Rahimi, Khosorov; Rauer, Sebastian Bernhard; Ghanem, Bader; Ma, Xiaohua; Pinnau, Ingo; Wessling, Matthias

    2017-07-27

    Dynamic sorption of ethanol and toluene vapor into ultrathin supported films of polymer of intrinsic microporosity PIM-1 down to a thickness of 6 nm are studied with a combination of in situ spectroscopic ellipsometry and in situ X-ray reflectivity. Both ethanol and toluene significantly swell the PIM-1 matrix and, at the same time, induce persistent structural relaxations of the frozen-in glassy PIM-1 morphology. For ethanol below 20 nm, three effects were identified. First, the swelling magnitude at high vapor pressures is reduced by about 30% as compared to that of thicker films. Second, at low penetrant activities (below 0.3p/p 0 ), films below 20 nm are able to absorb slightly more penetrant as compared with thicker films despite a similar swelling magnitude. Third, for the ultrathin films, the onset of the dynamic penetrant-induced glass transition P g has been found to shift to higher values, indicating higher resistance to plasticization. All of these effects are consistent with a view where immobilization of the superglassy PIM-1 at the substrate surface leads to an arrested, even more rigid, and plasticization-resistant, yet still very open, microporous structure. PIM-1 in contact with the larger and more condensable toluene shows very complex, heterogeneous swelling dynamics, and two distinct penetrant-induced relaxation phenomena, probably associated with the film outer surface and the bulk, are detected. Following the direction of the penetrant's diffusion, the surface seems to plasticize earlier than the bulk, and the two relaxations remain well separated down to 6 nm film thickness, where they remarkably merge to form just a single relaxation.

  5. Understanding the adhesion phenomena in carbohydrate-hydrogel-based systems: Water up-take, swelling and elastic detachment.

    Science.gov (United States)

    Caccavo, Diego; Lamberti, Gaetano; Cascone, Sara; Barba, Anna Angela; Larsson, Anette

    2015-10-20

    The bio-adhesion is a complex phenomenon which takes place when two materials (at least one of biological nature, the other usually is a polymeric one) are held together for extended periods of time, usually for local drug delivery purposes. Despite bio-adhesion is widely exploited in commercial pharmaceuticals such as the buccal patches, the underlying phenomena of the process are not completely clarified yet. In this study experimental tests, in which the role of biological membranes is played by a water-rich agarose gel whereas patches are mimicked by hydrogel tablets (made of Carbopol or of Carbopol added with NaCl), have been used to analyze the behavior of the model system above described. Tablets have been forced to adhere on the agarose gel, and after a given contact time they have been detached, recording the required forces. Furthermore weight gain of the tablets (the water transported from the agarose gel toward the tablet) has been quantified. Water transport (during the time in which the contact between tablet and agarose gel is held) and elastic part of mechanical response during the detachment are modelled to achieve a better understanding of the adhesion process. Both the two sub-models nicely reproduce, respectively, the weight gain as well as the swelling of the Carbopol tablets, and the point at which the mechanical response ceases to be purely elastic. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Swelling equilibrium of dentin adhesive polymers formed on the water-adhesive phase boundary: experiments and micromechanical model.

    Science.gov (United States)

    Misra, A; Parthasarathy, R; Ye, Q; Singh, V; Spencer, P

    2014-01-01

    During their application to the wet, oral environment, dentin adhesives can experience phase separation and composition change, which can compromise the quality of the hybrid layer formed at the dentin-adhesive interface. The chemical composition of polymer phases formed in the hybrid layer can be represented using a ternary water-adhesive phase diagram. In this paper, these polymer phases are characterized using a suite of mechanical tests and swelling experiments. The experimental results were evaluated using a granular micromechanics-based model incorporating poro-mechanical effects and polymer-solvent thermodynamics. The variation in the model parameters and model-predicted polymer properties was studied as a function of composition along the phase boundary. The resulting structure-property correlations provide insight into interactions occurring at the molecular level in the saturated polymer system. These correlations can be used for modeling the mechanical behavior of the hybrid layer, and are expected to aid in the design and improvement of water-compatible dentin adhesive polymers. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  7. Robust Polypropylene Fabrics Super-Repelling Various Liquids: A Simple, Rapid and Scalable Fabrication Method by Solvent Swelling.

    Science.gov (United States)

    Zhu, Tang; Cai, Chao; Duan, Chunting; Zhai, Shuai; Liang, Songmiao; Jin, Yan; Zhao, Ning; Xu, Jian

    2015-07-01

    A simple, rapid (10 s) and scalable method to fabricate superhydrophobic polypropylene (PP) fabrics is developed by swelling the fabrics in cyclohexane/heptane mixture at 80 °C. The recrystallization of the swollen macromolecules on the fiber surface contributes to the formation of submicron protuberances, which increase the surface roughness dramatically and result in superhydrophobic behavior. The superhydrophobic PP fabrics possess excellent repellency to blood, urine, milk, coffee, and other common liquids, and show good durability and robustness, such as remarkable resistances to water penetration, abrasion, acidic/alkaline solution, and boiling water. The excellent comprehensive performance of the superhydrophobic PP fabrics indicates their potential applications as oil/water separation materials, protective garments, diaper pads, or other medical and health supplies. This simple, fast and low cost method operating at a relatively low temperature is superior to other reported techniques for fabricating superhydrophobic PP materials as far as large scale manufacturing is considered. Moreover, the proposed method is applicable for preparing superhydrophobic PP films and sheets as well.

  8. Swelling equilibrium of dentin adhesive polymers formed on the water-adhesive phase boundary: Experiments and micromechanical model

    Science.gov (United States)

    Misra, Anil; Parthasarathy, Ranganathan; Ye, Qiang; Singh, Viraj; Spencer, Paulette

    2013-01-01

    During their application to the wet, oral environment, dentin adhesives can experience phase separation and composition change which can compromise the quality of the hybrid layer formed at the dentin-adhesive interface. The chemical composition of polymer phases formed in the hybrid layer can be represented using a ternary water-adhesive phase diagram. In this paper, these polymer phases have been characterized using a suite of mechanical tests and swelling experiments. The experimental results were evaluated using granular micromechanics based model that incorporates poro-mechanical effects and polymer-solvent thermodynamics. The variation of the model parameters and model-predicted polymer properties has been studied as a function of composition along the phase boundary. The resulting structure-property correlations provide insight into interactions occurring at the molecular level in the saturated polymer system. These correlations can be used for modeling the mechanical behavior of hybrid layer, and are expected to aid in the design and improvement of water-compatible dentin adhesive polymers. PMID:24076070

  9. Neck swelling due to skull base (pseudo)meningocele protruding through a congenital skull base bone defect: a case report.

    Science.gov (United States)

    Sharma, Rajeev; Singh, Bhoopendra; Kedia, Shweta; Laythalling, Rajinder Kumar

    2017-02-01

    Meningocele is defined as a protrusion of the meninges through an opening in the skull or spinal column, forming a bulge or sac filled with cerebrospinal fluid. A pseudomeningocele is defined as a cerebrospinal fluid (CSF) collection formed due to escape of CSF through a dural defect with trapping of CSF into the surrounding soft tissues. We herby report rare occurrence of a large (pseudo)meningocele in a young patient with congenital skull base defect presenting as upper lateral neck swelling. We present the case of a 17-year-old boy who had painless progressive swelling right side of the upper neck without any history of meningitis or CSF leak. He had a history of undergoing cranioplasty using steel plates for nontraumatic boggy swelling right parieto-occipital region at the age of 5 years at another hospital. Clinical examination showed painless swelling right side of the upper neck, with positive cough impulse and transillumination. CT head with cisternography showed a large right skull base defect through which a large pseudomeningocele was herniating, thus producing upper neck swelling and compressing oral cavity. The neck swelling and intraoral bulge reduced in size after the coperitoneal shunt. Differential diagnosis of (pseudo)meningocele should be considered while evaluating a painless progressive upper neck swelling having cough impulse and transillumination in a young patient.

  10. Effect of Impact Modifier Type on Water Absorption and Thickness Swelling Parameters of Wood Flour- Recycled Polypropylene Composites

    Directory of Open Access Journals (Sweden)

    Saman Ghahri

    2012-01-01

    Full Text Available In this research, the effect of impact modifier type on water diffusion coefficient, maximum water absorption and thickness swelling parameters of wood flour- recycled polypropylene composites were evaluated. For this purpose, a virgin PP was thermo-mechanically degraded by two times extrusion under controlled conditions in a twin-screw extruder at a rotor speed of 100 rpm and a temperature of 1900C. The virgin and recycled PP in 2nd stage, compatibilizer (0, 2 % w/w and wood flour were compounded at 50% weight sawdust loading in a counter-rotating twin-screw extruder in presence different type of impact modifiers (0, 6 % w/w. Ethylene vinyl acetate (EVA, ethylene-propylene-diene monomer (EPDM and acrylonitrile-butadiene-styrene (ABS were used as impact modifiers. The analysis of diffusion mechanism and thickness swelling rate were done based on Fick’s theory and swelling model for wood flour- recycled polypropylene composites. The composites containing two times recycled PP exhibited lower moisture diffusion coefficients, swelling rate parameter, maximum water absorption, thickness swelling. Also results showed that moisture diffusion coefficients and thickness swelling parameters of composites containing EVA are lower than composites containing EPDM and ABS. The use of compatibilizer decreased the moisture diffusion coefficients and thickness swelling parameters of the wood flour- recycled polypropylene composites

  11. Tuning of cellulose fibres' structure and surface topography: Influence of swelling and various drying procedures.

    Science.gov (United States)

    Hribernik, Silvo; Stana Kleinschek, Karin; Rihm, Rainer; Ganster, Johannes; Fink, Hans-Peter; Sfiligoj Smole, Majda

    2016-09-05

    Presented study deals with the pre-treatment of cellulose fibres with the aim to activate their surface and to enlarge their pore system, leading to an enhancement of fibres' affinity for subsequent functionalization processes. Swelling of fibres in aqueous solutions of sodium hydroxide opens their fibrillar structure, while freezing and freeze-drying retain this enlargement of the pore system, in contrast with conventional air or elevated temperature drying. Effect of different pre-treatment procedures on fibres' supramolecular structure, enlargement of their pore system, surface topography, zeta potential and mechanical properties was investigated. Degree of enhancement of the pore system depends on the concentration of sodium hydroxide and type of freezing; higher alkali concentrations are more effective, but at the cost of extensive deterioration of mechanical properties. Swelling of fibres in lower concentrations of NaOH, in combination with freeze drying, offers an acceptable compromise between enhancement of the fibres' pore system, changes in surface potential and tensile properties of treated fibres. Design of a suitable regime of swelling and drying of cellulose fibres results in an effective procedure for controlled tuning of their surface topography in combination with an increase of the available internal surface area and pore volume. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Preparation and characterization of oil palm frond based cellulose hydrogel and its swelling properties

    Science.gov (United States)

    Selvakumaran, Nesha; Lazim, Mohd Azwani Shah bin Mat

    2016-11-01

    Malaysia is one of the largest producer of palm oil thus the quantity of biomass each year from this industry is very large. The oil palm frond from palm oil industry can be used as a source of cellulose which can be incorporated into hydrogel to be used as adsorbent. This research reported how to disperse 2 % cellulose in a `green-solution' prepared by using urea and sodium hydroxide. Polymerization is carried out between the monomers polyacrylamide and cellulose using microwave to form hydrogel. Hydrogel with 2 % cellulose have a swelling index of 1814 %. Meanwhile, zero hydrogel which is made with only polyacrylamide has swelling index of 15 %. Scanning electron microscope shows that cellulose hydrogel have a rough surface compared with zero hydrogel. This might attribute to the high swelling index for cellulose hydrogel compared with zero hydrogel. Meanwhile, FTIR shows that successful polymerization has occurred between polyacrylamide and cellulose with the characteristic band at 1657.99 cm-1 which is for N-H bond.

  13. The role of Swelling in Diffusion-Controlled Drug Release: a Lattice Monte Carlo Approach

    Science.gov (United States)

    Ignacio, Maxime; Slater, Gary W.

    A common approach used to control drug release rate consists in encapsulating the drug molecules inside a hydrogel (a network of hydrophilic cross-linked polymers). Placed in aqueous media or under the action of an external stimuli, the hydrogel can swell. This phenomenon leads to a non-trivial relation between the swelling of the hydrogel matrix, the diffusion properties of the drug molecules and the performance of a drug delivery system. We propose to investigate this problem using a novel Lattice Monte Carlo approach. In our LMC scheme, both the diffusion coefficient of the drug molecules and the lattice step size evolve in time as the water penetrates inside the system. Due to the resulting time- and space-dependent diffusivity, there are different interpretations of the stochastic term in the relevant overdamped Langevin equation (i.e ``Ito-Stratonovich dilemma''). First, we examine how each calculus changes the release properties of the system in both the swelling-controlled and the diffusion-controlled limits. Second, we discuss the validity of the empirical mathematic models often used to fit the release data.

  14. Void-swelling and precipitation in a neutron-irradiated, niobium-stabilised austenitic stainless steel

    Science.gov (United States)

    Williams, T. M.; Titchmarsh, J. M.; Arkell, D. R.

    1982-06-01

    Unstressed specimens of FV548 niobium-stabilised austenitic steel in three heat-treatment conditions (1150°C solutiontreated, 20% cold-worked, and 850°C aged) have been neutron-irradiated in the Dounreay Fast Reactor in the temperature range 380°-738°C and to displacement doses of up to 30 dpa. The irradiated specimens have been examined using transmission electron microscopy and EDX techniques to establish the void-swelling and precipitation behaviour under neutron irradiation. Where possible, the observations are compared with results obtained on type 316 steel. The similarities and differences in the behaviour of the two steels are used in an attempt to understand the factors affecting the precipitation under irradiation and the void-swelling behaviour of FV548 and type 316 steels. Irradiation is shown to enhance the formation of some precipitate phases (e.g. G-phase and carbides of the M 6C type) while having no effect on others (e.g. Sigma phase and M 23C 6). It is concluded that fine intragranular dispersions of niobium carbide particles play a major role in suppressing void-swelling in neutron-irradiated FV548 steel at relatively high irradiation temperatures.

  15. Disassembly of actin structures by nanosecond pulsed electric field is a downstream effect of cell swelling.

    Science.gov (United States)

    Pakhomov, Andrei G; Xiao, Shu; Pakhomova, Olga N; Semenov, Iurii; Kuipers, Marjorie A; Ibey, Bennett L

    2014-12-01

    Disruption of the actin cytoskeleton structures was reported as one of the characteristic effects of nanosecond-duration pulsed electric field (nsPEF) in both mammalian and plant cells. We utilized CHO cells that expressed the monomeric fluorescent protein (mApple) tagged to actin to test if nsPEF modifies the cell actin directly or as a consequence of cell membrane permeabilization. A train of four 600-ns pulses at 19.2 kV/cm (2 Hz) caused immediate cell membrane poration manifested by YO-PRO-1 dye uptake, gradual cell rounding and swelling. Concurrently, bright actin features were replaced by dimmer and uniform fluorescence of diffuse actin. To block the nsPEF-induced swelling, the bath buffer was isoosmotically supplemented with an electropore-impermeable solute (sucrose). A similar addition of a smaller, electropore-permeable solute (adonitol) served as a control. We demonstrated that sucrose efficiently blocked disassembly of actin features by nsPEF, whereas adonitol did not. Sucrose also attenuated bleaching of mApple-tagged actin in nsPEF-treated cells (as integrated over the cell volume), although did not fully prevent it. We conclude that disintegration of the actin cytoskeleton was a result of cell swelling, which, in turn, was caused by cell permeabilization by nsPEF and transmembrane diffusion of solutes which led to the osmotic imbalance. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Prediction of postoperative facial swelling, pain and trismus following third molar surgery based on preoperative variables

    Science.gov (United States)

    de Souza-Santos, Jadson A.; Martins-Filho, Paulo R.; da Silva, Luiz C.; de Oliveira e Silva, Emanuel D.; Gomes, Ana C.

    2013-01-01

    Objective: This paper investigates the relationship between preoperative findings and short-term outcome in third molar surgery. Study design: A prospective study was carried out involving 80 patients who required 160 surgical extractions of impacted mandibular third molars between January 2009 and December 2010. All extractions were performed under local anesthesia by the same dental surgeon. Swelling and maximal inter-incisor distance were measured at 48 h and on the 7th day postoperatively. Mean visual analogue pain scores were determined at four different time periods. Results: One-hundred eight (67.5%) of the 160 extractions were performed on male subjects and 52 (32.5%) were performed on female subjects. Median age was 22.46 years. The amount of facial swelling varied depending on gender and operating time. Trismus varied depending on gender, operating time and tooth sectioning. The influence of age, gender and operating time varied depending on the pain evaluation period (p trismus and pain) differ depending on the patients’ characteristics (age, gender and body mass index). Moreover, surgery characteristics such as operating time and tooth sectioning were also associated with postoperative variables. Key words:Third molar extraction, pain, swelling, trismus, postoperative findings, prediction. PMID:23229245

  17. Low-temperature swelling in LWR internal components: a computational assessment

    Energy Technology Data Exchange (ETDEWEB)

    Stoller, Roger E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Golubov, Stanislav I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Barashev, Alexander V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)

    2015-01-01

    A modern cluster dynamics model has been used to investigate the materials and irradiation parameters that control microstructural evolution under the relatively low-temperature exposure conditions that are representative of the operating environment for in-core light water reactor components. The focus is on components fabricated from austenitic stainless steel. The model accounts for the synergistic interaction between radiation-produced vacancies and the helium that is produced by nuclear transmutation reactions. Cavity nucleation rates are shown to be relatively high in this temperature regime (275 to 325 °C), but are sensitive to assumptions about the fine-scale microstructure produced under low-temperature irradiation. The cavity nucleation rates observed run counter to the expectation that void swelling would not occur under these conditions. This expectation was based on previous research on void swelling in austenitic steels in fast reactors. This misleading impression arose primarily from an absence of relevant data. The results of the computational modeling are generally consistent with recent data obtained by examining ex-service components. The long-term objective of this research is to provide a predictive model of void swelling at relevant lifetime exposures to support extended reactor operations.

  18. Effect of filler water absorption on water swelling properties of natural rubber

    Science.gov (United States)

    Trakuldee, J.; Boonkerd, K.

    2017-07-01

    The efficient water swelling rubber can be obtained by using high hydrophilic rubber such as chloroprene rubber. However, chloroprene rubber is synthetic rubber developed from the petroleum. Recently, many researches try to replace the usage of synthetic rubber with natural rubber. This is not only due to the concerning of environment but the cost reduction as well. However, natural rubber is hydrophobic, thus not absorbing water. To develop the water swelling rubber from natural rubber, the addition of water absorption filler is needed. The study was aimed to formulate water swelling rubber from natural rubber filled with sodium polyacrylate (SA)/sodium bentonite clay (SBC) hybrid filler used to water absorbent. The filler loading was kept constantly at 150 phr. The effect of SA/SBC ratio varied from 1:0, 1:1, 1:2 and 1:3 on the water absorption of the hybrid filled natural rubber was determined. The obtained result showed that the water adsorption proportionally increased with increasing SA loading but decreased with increasing SBC loading. The effect of glycidyl methacrylate (GM) and poly ethylene glycol (PEG) on the water absorption was studied later. The result from a scanning electron microscope depicted that the presence of GM can depress the falling out of SA from the rubber matrix while the presence of PEG increased water absorption.

  19. Swelling, Functionalization, and Structural Changes of the Nanoporous Layered Silicates AMH-3 and MCM-22

    KAUST Repository

    Kim, Wun-gwi

    2011-06-21

    Nanoporous layered silicate materials contain 2D-planar sheets of nanoscopic thickness and ordered porous structure. In comparison to porous 3D-framework materials such as zeolites, they have advantages such as significantly increased surface area and decreased diffusion limitations because the layers can potentially be exfoliated or intercalated into polymers to form nanocomposite materials. These properties are particularly interesting for applications as materials for enhancing molecular selectivity and throughput in composite membranes. In this report, the swelling and surface modification chemistry of two attractive nanoporous layered silicate materials, AMH-3 and MCM-22, were studied. We first describe a method, using long-chain diamines instead of monoamines, for swelling of AMH-3 while preserving its pore structure to a greater extent during the swelling process. Then, we describe a stepwise functionalization method for functionalizing the layer surfaces of AMH-3 and MCM-22 via silane condensation reactions. The covalently attached hydrocarbon chain molecules increased the hydrophobicity of AMH-3 and MCM-22 layer surfaces and therefore allow the possibility of effectively dispersing these materials in polymer matrices for thin film/membrane applications. © 2011 American Chemical Society.

  20. Cutaneous lymphatic malformation characterized by swelling of digits: a report of six cases.

    Science.gov (United States)

    Wang, Lei; Gao, Tianwen; Wang, Gang

    2014-05-01

    Cutaneous lymphatic malformations represent a group of heterogeneous diseases. In clinical practice, some cases of cutaneous lymphatic malformation have been found to differ from the well-characterized entities, and are difficult to classify. To report the clinical, histopathological and immunohistochemical characteristics of six cases of lymphatic malformation characterized by swelling of the digits. Six patients with swelling of the digits were included in this study. Histopathological examination and immunohistochemical staining of CD31, D2-40, Prox1, Wilms tumor 1 (WT-1) and human herpesvirus-8 (HHV-8) were performed for all cases. All cases were congenital lesions and presented as swelling of single or multiple digits. Histopathologically, the lesions showed proliferation of small-to-medium-sized vessels in the dermis and subcutaneous tissue. These abnormal vessels were positive for CD31, D2-40 and Prox1, and negative for WT-1 and HHV-8. The six cases reported herein represent a specific cutaneous lymphatic malformation different from previously reported entities. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.