Permeation of limonene through disposable nitrile gloves using a dextrous robot hand

Science.gov (United States)

Banaee, Sean; S Que Hee, Shane

2017-01-01

Objectives: The purpose of this study was to investigate the permeation of the low-volatile solvent limonene through different disposable, unlined, unsupported, nitrile exam whole gloves (blue, purple, sterling, and lavender, from Kimberly-Clark). Methods: This study utilized a moving and static dextrous robot hand as part of a novel dynamic permeation system that allowed sampling at specific times. Quantitation of limonene in samples was based on capillary gas chromatography-mass spectrometry and the internal standard method (4-bromophenol). Results: The average post-permeation thicknesses (before reconditioning) for all gloves for both the moving and static hand were more than 10% of the pre-permeation ones (P≤0.05), although this was not so on reconditioning. The standardized breakthrough times and steady-state permeation periods were similar for the blue, purple, and sterling gloves. Both methods had similar sensitivity. The lavender glove showed a higher permeation rate (0.490±0.031 μg/cm2/min) for the moving robotic hand compared to the non-moving hand (P≤0.05), this being ascribed to a thickness threshold. Conclusions: Permeation parameters for the static and dynamic robot hand models indicate that both methods have similar sensitivity in detecting the analyte during permeation and the blue, purple, and sterling gloves behave similarly during the permeation process whether moving or non-moving. PMID:28111415

Determinação da espessura da camada polimérica de fases estacionárias imobilizadas para cromatografia líquida de alta eficiência por termogravimetria Determination of polymeric layer thickness on immobilized stationary phases for high-performance liquid chromatography using thermogravimetric analyses

Directory of Open Access Journals (Sweden)

Anizio M. Faria

2008-01-01

Full Text Available This paper presents a simple and practical thermogravimetric method for determining the layer thickness of immobilized polymer stationary phases used in reversed-phase high-performance liquid chromatography. In this method, the weight loss of different polysiloxanes immobilized onto chromatographic supports, determined over the temperature range 150-650 ºC, demonstrated excellent agreement with the sum of carbon and hydrogen content obtained by elemental analysis. The results presented here suggest that the thermogravimetric procedure is an accurate and precise method to determine the polymeric material content on polymer-coated stationary phases.

Alteration of skin hydration and its barrier function by vehicle and permeation enhancers: a study using TGA, FTIR, TEWL and drug permeation as markers.

Science.gov (United States)

Shah, D K; Khandavilli, S; Panchagnula, R

2008-09-01

Vehicles and permeation enhancers (PEs) used in transdermal drug delivery (TDD) of a drug can affect skin hydration, integrity and permeation of the solute administered. This investigation was designed to study the effect of the most commonly used vehicles and PEs on rat skin hydration, barrier function and permeation of an amphiphilic drug, imipramine hydrochloride (IMH). An array of well-established techniques were used to confirm the findings of the study. Thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy were used to determine changes in skin hydration. Alteration of the stratum corneum (SC) structure was investigated using FTIR studies. To monitor the barrier function alteration, transepidermal water loss (TEWL) measurement and permeation studies were performed. Our findings indicate that with hydration, there was an increase in the bound water content of the skin, and pseudoequilibrium of hydration (a drastic decrease in hydration rate) was achieved at around 12 h. Hydration increased the ratio between amide-I and amide-II peaks in FTIR and reduced the C-H stretching peak area. Both propylene glycol (PG) and ethanol (EtOH) dehydrated skin, with the latter showing a predominant effect. Furthermore, it was confirmed that PG and EtOH decreased the bound water content due to alteration in the protein domains and extraction of SC lipids, respectively. The effect of hydration on the SC was found to be similar to that reported for temperature. Permeation studies revealed that the dehydration caused by vehicles decreased IMH flux, whereas the flux was enhanced by PEs. The role of partition was predominant for the permeation of IMH through dehydrated skin. A synergistic effect was observed for PG and menthol in the enhancement of IMH. Further findings provided strong evidence that PG affects protein domains and EtOH extracts lipids from the bilayer. Both PG and EtOH, with or without PEs, increased TEWL. Initial TEWL was well

Morphology and thermal degradation study of poly(lactic acid)/synthetic mica composites

International Nuclear Information System (INIS)

Souza, D.H.S.; Dias, M.L.

2010-01-01

Poly(lactic acid) (PLA)/synthetic mica composites has been little studied in the literature. In this work, an organophilic synthetic mica was used to prepare PLA nanocomposites. The composites were obtained at an internal mixer containing 3, 5, 7 and 10 wt% of mica. The materials were analyzed by x-ray diffraction, thermogravimetric analysis and gel permeation chromatography. (author)

Permeation of cytotoxic formulations through swatches from selected medical gloves.

Science.gov (United States)

Klein, Michael; Lambov, Nikolai; Samev, Nikola; Carstens, Gerhard

2003-05-15

The permeability of selected medical glove materials to various cytotoxic agents is described. Fifteen cytotoxic agents were prepared at the highest concentrations normally encountered by hospital personnel. Four single-layer and two double-layer glove systems made of two materials--latex and neoprene--were exposed to the drugs for 30, 60, 90, 120, 150, and 180 minutes. Circular sections of the glove material were cut from the cuff and evaluated without any pretreatment. Permeability tests were conducted in an apparatus consisting of a donor chamber containing the cytotoxic solution and a collection chamber filled with water (the acceptor medium). The two sections were separated by the glove material. Permeating portions, collected in water as the acceptor medium, were analyzed by either ultraviolet-visible light spectrophotometry or high-performance liquid chromatography (HPLC). Permeation rates were calculated on the basis of the concentration of the cytotoxic agent in the acceptor medium. Spectrophotometric measurements were taken every 30 minutes, and HPLC analysis was performed at the end of the three-hour period. Average permeation rates for 14 drugs were low (materials. All glove materials tested were impermeable to most of the cytotoxic agents over a period of three hours. Carmustine was the only agent that substantially permeated single-layer latex glove materials. Permeation of most tested cytotoxic formulations was low through swatches of material from various medical gloves.

Molecular weights and molecular weight distributions of irradiated cellulose fibers by gel permeation chromatography

International Nuclear Information System (INIS)

Kusama, Y.; Kageyama, E.; Shimada, M.; Nakamura, Y.

1976-01-01

Radiation degradation of cellulose fibers was investigated by gel permeation chromatography (GPC). Scoured cotton of Mexican variety (cellulose I), Polynosic rayon (cellulose II), and their microcrystalline celluloses obtained by hydrolysis of the original fibers were irradiated by Co-60 γ-rays under vacuum or humid conditions. The irradiated samples were then nitrated under nondegradative conditions. The molecular weights and molecular weight distributions were measured by GPC using tetrahydrofuran as solvent. The relationship between molecular weight and elution count was obtained with cellulose trinitrate standards fractionated by preparative GPC. The degree of polymerization of the fibers decreased with increasing irradiation dose, but their microcrystalline celluloses were only slightly degraded by irradiation, especially in microcrystalline cellulose from cellulose I. Degradation of the fibers irradiated under humid conditions was less than that irradiated under vacuum. It was found that the G-values for main-chain scission for the irradiated cellulose I, cellulose II, microcrystalline cellulose I, and microcrystalline cellulose II were 2.8, 2.9, less than 1, and 2.9, respectively, but the G-value for main-chain scission for the irradiated cellulose II was increased to 11.2 at irradiation doses above 3 Mrad. Consequently, it is inferred that cellulose molecules in the amorphous regions are degraded more readily, and the well-aligned molecules in crystalline regions are not as easily degraded by irradiation

Thermogravimetric Analysis Laboratory

Data.gov (United States)

Federal Laboratory Consortium — At NETL’s Thermogravimetric Analysis Laboratory in Morgantown, WV, researchers study how chemical looping combustion (CLC) can be applied to fossil energy systems....

Selection of imprinted nanoparticles by affinity chromatography.

Science.gov (United States)

Guerreiro, António R; Chianella, Iva; Piletska, Elena; Whitcombe, Michael J; Piletsky, Sergey A

2009-04-15

Soluble molecularly imprinted nanoparticles were synthesised via iniferter initiated polymerisation and separated by size via gel permeation chromatography. Subsequent fractionation of these particles by affinity chromatography allowed the separation of high affinity fractions from the mixture of nanoparticles. Fractions selected this way possess affinity similar to that of natural antibodies (K(d) 6.6x10(-8)) M and were also able to discriminate between related functional analogues of the template.

Analysis of humic colloid borne trace elements by flow field-flow fractionation, gel permeation chromatography and icp-mass spectrometry

International Nuclear Information System (INIS)

Ngo, Manh Thang; Beck, H.P; Geckeis, H.; Kim, J.I.

1999-01-01

Groundwater samples containing aquatic humic substances are analyzed by flow field- flow fractionation (FFFF) and gel permeation chromatography (GPC). Natural concentrations of U, Th and rare earth elements (REE) in a size-fractionated groundwater sample are analyzed by on-line coupling of inductively coupled plasma-mass spectrometry (ICP-MS) to either FFFF or GPC. The uranium, thorium, and REE are found to be quantitatively attached to colloidal species in the investigated groundwater sample. Their distribution in different colloid size fractions, however, is quite heterogeneous. Both, FFFF and GPC reveal that Th and REE are preferentially located in the size fraction > 50 kDalton. U is also attached to low molecular weight humic acid, similar to Fe and Al. This finding could be qualitatively reproduced by sequential ultrafiltration. The results are interpreted in terms of different binding mechanisms for the individual elements in the heterogeneous humic macromolecules. The inclusion of actinides into larger aggregates of aquatic humic acid might explain the considerable kinetic hindrance of actinide-humic acid dissociation reactions described in the literature. (authors)

Resistance of gloves and protective clothing materials to permeation of cytostatic solutions.

Science.gov (United States)

Krzemińska, Sylwia; Pośniak, Małgorzata; Szewczyńska, Małgorzata

2018-01-15

The objective of the work was to determine the resistance of selected protective clothing and glove materials to permeation of cytostatics such as docetaxel, fluorouracil, and doxorubicin. The following glove materials were used: natural rubber latex (code A), acrylonitrile-butadiene rubber (code B) and chloroprene rubber (code C). In addition, we tested a layered material composed of a non-woven polyester (PES), a polypropylene (PP) film, and a non-woven PP used for protective coats (code D). The cytostatics were analyzed by liquid chromatography with diode array detection. The tested samples were placed in a purpose-built permeation cell modified to be different from that specified in the standard EN 6529:2001. The tested materials were characterized by good resistance to solutions containing 2 out of the 3 selected cytostatics: doxorubicin and 5-fluorouracil, as indicated by a breakthrough time of over 480 min. Equally high resistance to permeation of the third cytostatic (docetaxel) was exhibited by natural rubber latex, acrylonitrile-butadiene rubber, and chloroprene rubber. However, docetaxel permeated much more readily through the clothing layered material, compromising its barrier properties. It was found that the presence of additional components in cytostatic preparations accelerated permeation through material samples, thus deteriorating their barrier properties. Int J Occup Med Environ Health 2018;31(3):341-350. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Effect of phonophoresis on skin permeation of commercial anti-inflammatory gels: sodium diclofenac and ketoprofen.

Science.gov (United States)

Souza, Jaqueline; Meira, Alianise; Volpato, Nadia Maria; Mayorga, Paulo; Gottfried, Carmem

2013-09-01

This study evaluated the use of ultrasound in combination with the commercial anti-inflammatory drugs ketoprofen and sodium diclofenac, according to the parameters used in physiotherapy. Ketoprofen and sodium diclofenac were used in the Franz diffusion cell model adapted to an ultrasound transducer in three conditions: no ultrasound, one application of ultrasound and two applications of ultrasound. High-performance liquid chromatography was used to quantify the total amount of drug permeating skin per unit area, as well as flux and latency. The results showed that for ketoprofen, the amount of drug permeating skin and flux increased with two ultrasound applications. Permeation of sodium diclofenac decreased in the presence of ultrasound. Ultrasound parameters and drug properties must be considered in the use of phonophoresis. Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Evaluation of the suitability of chromatographic systems to predict human skin permeation of neutral compounds.

Science.gov (United States)

Hidalgo-Rodríguez, Marta; Soriano-Meseguer, Sara; Fuguet, Elisabet; Ràfols, Clara; Rosés, Martí

2013-12-18

Several chromatographic systems (three systems of high-performance liquid chromatography and two micellar electrokinetic chromatography systems) besides the reference octanol-water partition system are evaluated by a systematic procedure previously proposed in order to know their ability to model human skin permeation. The precision achieved when skin-water permeability coefficients are correlated against chromatographic retention factors is predicted within the framework of the solvation parameter model. It consists in estimating the contribution of error due to the biological and chromatographic data, as well as the error coming from the dissimilarity between the human skin permeation and the chromatographic systems. Both predictions and experimental tests show that all correlations are greatly affected by the considerable uncertainty of the skin permeability data and the error associated to the dissimilarity between the systems. Correlations with much better predictive abilities are achieved when the volume of the solute is used as additional variable, which illustrates the main roles of both lipophilicity and size of the solute to penetrate through the skin. In this way, the considered systems are able to give precise estimations of human skin permeability coefficients. In particular, the HPLC systems with common C18 columns provide the best performances in emulating the permeation of neutral compounds from aqueous solution through the human skin. As a result, a methodology based on easy, fast, and economical HPLC measurements in a common C18 column has been developed. After a validation based on training and test sets, the method has been applied with good results to the estimation of skin permeation of several hormones and pesticides. Copyright © 2013 Elsevier B.V. All rights reserved.

Permeation through graphene ripples

Science.gov (United States)

Liang, Tao; He, Guangyu; Wu, Xu; Ren, Jindong; Guo, Hongxuan; Kong, Yuhan; Iwai, Hideo; Fujita, Daisuke; Gao, Hongjun; Guo, Haiming; Liu, Yingchun; Xu, Mingsheng

2017-06-01

Real graphene sheets show limited anti-permeation performance deviating from the ideally flat honeycomb carbon lattice that is impermeable to gases. Ripples in graphene are prevalent and they could significantly influence carrier transport. However, little attention has been paid to the role of ripples in the permeation properties of graphene. Here, we report that gases can permeate through graphene ripples at room temperature. The feasibility of gas permeation through graphene ripples is determined by detecting the initial oxidation sites of Cu surface covered with isolated graphene domain. Nudged elastic band (NEB) calculations demonstrate that the oxygen atom permeation occurs via the formation of C-O-C bond, in which process the energy barrier through the rippled graphene lattice is much smaller than that through a flat graphene lattice, rendering permeation through ripples more favorable. Combining with the recent advances in atoms intercalation between graphene and metal substrate for transfer-free and electrically insulated graphene, this discovery provides new perspectives regarding graphene’s limited anti-permeation performance and evokes for rational design of graphene-based encapsulation for barrier and selective gas separation applications through ripple engineering.

Neo-Geometric Copper Nanocrystals by Competitive, Dual Surfactant-Mediated Facet Adsorption Controlling Skin Permeation

Directory of Open Access Journals (Sweden)

Karmani Murugan

2016-11-01

Full Text Available Neogeometric copper nanoparticles (CuNPs have various applications yet its synthesis still proves to be challenging with regards to self-assembly and uniformity control. This study aimed to synthesize shape-specific CuNPs in the biomedical application of ascertaining skin permeation and retention of the CuNPs as a drug delivery system. The approach to the shape design involved the dual control of two surfactants to direct the shape organisation of the nanoparticles (NPs while an interesting aspect of the study showed the competitive adsorption of the surfactants onto the nanocrystal facets to direct facet growth. The resulting copper nanoparticles were characterised using X-ray diffraction (XRD and electron diffraction spectra analysis (EDS for elemental and crystalline analysis. Thermogravimetric Analysis (TGA identified the degradation of the surfactant coat and the synthesis of a novel copper-polymer complex and extensive transmission electron microscopy (TEM was conducted to determine the nanoparticle morphology. Epidermal skin tissue served as the model for permeation studies of five idealistic nano-geometries and investigated its application in drug delivery with regards to cellular internalisation and transbarrier transport of the geometric CuNPs. A mechanistic consideration for shape control is discussed.

SYNTHESIS OF AMPHIPHILIC COMB-SHAPED COPOLYMERS USED FOR SURFACE MODIFICATION OF PVDF MEMBRANES

Institute of Scientific and Technical Information of China (English)

徐又一

2009-01-01

The synthesis of a novel amphiphilic comb-shaped copolymer consisting of a main chain of styrene-(N-(4- hydroxyphenyl) maleimide)(SHMI) copolymer and poly(ethylene glycol) methyl ether methacrylate(PEGMA) side groups was achieved by atom transfer radical polymerization(ATRP).The amphiphilic copolymers were characterized by ~1H-NMR, Fourier transform infrared(FTIR) spectroscopy and gel permeation chromatography(GPC).From thermogravimetric analysis (TGA),the decomposition temperature of SHMI-g-PEGMA is low...

In-pile tritium permeation experiment

International Nuclear Information System (INIS)

Longhurst, G.R.; Miller, L.G.; Watts, K.D.; Kershner, C.J.; Rogers, M.L.

1982-01-01

The experiments in progress are examining various aspects of the permeation of hydrogen isotopes through fusion materials. Of particular importance will be the measurement of permeation due to ion implantation in the presence of a neutron radiation field. Theoretical and early experimental results for these experiments have suggested that sufficient tritium will permeate fusion reactor interior structures that development of a permeation barrier will be needed. (orig.)

In-pile tritium permeation experiment

Energy Technology Data Exchange (ETDEWEB)

Longhurst, G.R.; Miller, L.G.; Watts, K.D. (Idaho National Engineering Lab., Idaho Falls (USA)); Kershner, C.J.; Rogers, M.L. (Monsanto Research Corp., Miamisburg, OH (USA). Mound Facility)

The experiments in progress are examining various aspects of the permeation of hydrogen isotopes through fusion materials. Of particular importance will be the measurement of permeation due to ion implantation in the presence of a neutron radiation field. Theoretical and early experimental results for these experiments have suggested that sufficient tritium will permeate fusion reactor interior structures that development of a permeation barrier will be needed.

LIBRETTO-3: modelling tritium extraction/permeation and evaluation of permeation barriers under irradiation

International Nuclear Information System (INIS)

Sedano, L.A.; Fuetterer, M.A.; Viola, R.; Dies, X.

1996-01-01

Permeation barriers are required in order to limit the size and cost of the detritiation plants for future fusion reactor blankets of the water-cooled Pb-17Li type. The LIBRETTO irradiations were performed to evaluate the efficiency of permeation barriers under high flux reactor (HFR) conditions. Tritium extraction and permeation characteristics from Pb-17Li under variable temperatures 553-723 K, H 2 doping (0-1 vol%) and purge gas flow rates 20-100 scc/min were tested in LIBRETTO-3. An external TiC coating, an internal (TiC+Al 2 O 3 ), both produced by chemical vapour deposition (CVD), and an internal Al 2 O 3 produced by pack cementation (PC) on AISI 316L steel were tested as permeation barriers. The release mechanisms, experimental uncertainties and method for permeation barriers qualification are presented. As a result permeation reduction factors (PRF) at 0.1 dpa of 17 and 34 were obtained for the CVD-Al 2 O 3 at 498 K and for the PC-Al 2 O 3 at 508 K, respectively. These values were confirmed by a residence time analysis and are higher than in a preliminary analysis. (orig.)

Deuterium permeation through Flibe facing materials

International Nuclear Information System (INIS)

Fukada, S.; Anderl, R.A.; Smolik, G.R.

2004-01-01

Experiment of deuterium permeation through Ni facing with purified Flibe is being carried out under the Japan-US joint research project (JUPITER-II). The experiment has been proceeding in the following phases; (i) fabrication and assembly of a dual-probe permeation apparatus, (ii) a single-probe Ni/D 2 , permeation experiment without Flibe, (iii) a dual-probe Ar/Ni/D 2 permeation experiment without Flibe, (iv) Flibe chemical purification by HF/H 2 gas bubbling, (v) physical purification by Flibe transport through a porous Ni filter, (vi) Ar/Ni/Flibe/Ni/D 2 permeation experiment using the dual Ni probe, and (vii) Ar/Ni/Flibe/Ni/HT permeation experiment. The present paper describe results until the Ar/Ni/Flibe/Ni/D 2 permeation experiment in detail. (author)

Fabrication, appraisal, and transdermal permeation of sildenafil citrate-loaded nanostructured lipid carriers versus solid lipid nanoparticles

Science.gov (United States)

Elnaggar, Yosra SR; El-Massik, Magda A; Abdallah, Ossama Y

2011-01-01

Although sildenafil citrate (SC) is used extensively for erectile dysfunction, oral delivery of SC encounters many obstacles. Furthermore, the physicochemical characteristics of this amphoteric drug are challenging for delivery system formulation and transdermal permeation. This article concerns the assessment of the potential of nanomedicine for improving SC delivery and transdermal permeation. SC-loaded nanostructured lipid carriers (NLCs) and solid lipid nanoparticles (SLNs) were fabricated using a modified high-shear homogenization technique. Nanoparticle optimization steps included particle size analysis, entrapment efficiency (EE) determination, freeze-drying and reconstitution, differential scanning calorimetry, in vitro release, stability study and high-performance liquid chromatography analysis. Transdermal permeation of the nanocarriers compared with SC suspension across human skin was assessed using a modified Franz diffusion cell assembly. Results revealed that SLNs and NLCs could be optimized in the nanometric range (180 and 100 nm, respectively) with excellent EE (96.7% and 97.5%, respectively). Nanoparticles have significantly enhanced in vitro release and transdermal permeation of SC compared with its suspensions. Furthermore, transdermal permeation of SC exhibited higher initial release from both SLN and NLC formulations followed by controlled release, with promising implications for faster onset and longer drug duration. Nanomedicines prepared exhibited excellent physical stability for the study period. Solid nanoparticles optimized in this study successfully improved SC characteristics, paving the way for an efficient topical Viagra® product. PMID:22238508

Testing of Disposable Protective Garments Against Isocyanate Permeation From Spray Polyurethane Foam Insulation.

Science.gov (United States)

Mellette, Michael P; Bello, Dhimiter; Xue, Yalong; Yost, Michael; Bello, Anila; Woskie, Susan

2018-05-12

Diisocyanates (isocyanates), including methylene diphenyl diisocyanate (MDI), are the primary reactive components of spray polyurethane foam (SPF) insulation. They are potent immune sensitizers and a leading cause of occupational asthma. Skin exposure to isocyanates may lead to both irritant and allergic contact dermatitis and possibly contribute to systemic sensitization. More than sufficient evidence exists to justify the use of protective garments to minimize skin contact with aerosolized and raw isocyanate containing materials during SPF applications. Studies evaluating the permeation of protective garments following exposure to SPF insulation do not currently exist. To conduct permeation testing under controlled conditions to assess the effectiveness of common protective gloves and coveralls during SPF applications using realistic SPF product formulations. Five common disposable garment materials [disposable latex gloves (0.07 mm thickness), nitrile gloves (0.07 mm), vinyl gloves (0.07 mm), polypropylene coveralls (0.13 mm) and Tyvek coveralls (0.13 mm)] were selected for testing. These materials were cut into small pieces and assembled into a permeation test cell system and coated with a two-part slow-rise spray polyurethane foam insulation. Glass fiber filters (GFF) pretreated with 1-(9-anthracenylmethyl)piperazine) (MAP) were used underneath the garment to collect permeating isocyanates. GFF filters were collected at predetermined test intervals between 0.75 and 20.00 min and subsequently analyzed using liquid chromatography-tandem mass spectrometry. For each garment material, we assessed (i) the cumulative concentration of total isocyanate, including phenyl isocyanate and three MDI isomers, that effectively permeated the material over the test time; (ii) estimated breakthrough detection time, average permeation rate, and standardized breakthrough time; from which (iii) recommendations were developed for the use of similar protective garments following

Improved Quantitation of Gluten in Wheat Starch for Celiac Disease Patients by Gel-Permeation High-Performance Liquid Chromatography with Fluorescence Detection (GP-HPLC-FLD).

Science.gov (United States)

Scherf, Katharina Anne; Wieser, Herbert; Koehler, Peter

2016-10-12

Purified wheat starch (WSt) is commonly used in gluten-free products for celiac disease (CD) patients. It is mostly well-tolerated, but doubts about its safety for CD patients persist. One reason may be that most ELISA kits primarily recognize the alcohol-soluble gliadin fraction of gluten, but insufficiently target the alcohol-insoluble glutenin fraction. To address this problem, a new sensitive method based on the sequential extraction of gliadins, glutenins, and gluten from WSt followed by gel-permeation high-performance liquid chromatography with fluorescence detection (GP-HPLC-FLD) was developed. It revealed that considerable amounts of glutenins were present in most WSt. The gluten contents quantitated by GP-HPLC-FLD as sum of gliadins and glutenins were higher than those by R5 ELISA (gluten as gliadin content multiplied by a factor of 2) in 19 out of 26 WSt. Despite its limited selectivity, GP-HPLC-FLD may be applied as confirmatory method to ELISA to quantitate gluten in WSt.

Evaluation of peracetic acid permeation during flash sterilization through pharmaceutical plastic polymers used in cytotoxic reconstitution units.

Science.gov (United States)

Havard, Laurent; Fellous-Jerome, Joelle; Bonan, Brigitte; Pradeau, Dominique; Prognon, Patrice

2005-01-01

Peracetic acid (PAA) permeation in flash sterilization was studied using three different plastic infusion bags made of polypropylene and polyethylene, filled with glucose 5% or NaCl 0.9%. The pH was measured and acetic acid (AA) and PAA concentrations were made by reverse phase high-performance liquid chromatography (RP-HPLC). PAA was derivatized by oxidation of methyl tolyl sulfide (MTS) into methyl tolyl sulfoxide (MTSO) detected by ultraviolet (UV) absorbance at 230 nm. The technique has a sensitivity of 0.3 microg x L(-1) and was highly specific. Results showed that pH measurements remain constant and demonstrated the absence of PAA permeation, which was confirmed by the absence of AA permeation regardless of the brand tested, with both unwrapped and overwrapped infusion bags, when flash sterilization is applied. These results allow flash sterilization to be performed with unwrapped infusion bags without any risk of drug degradation by PAA. This makes compounding safer and easier, which improves productivity.

On Diffusion and Permeation

KAUST Repository

Peppin, Stephen S. L.

2009-01-01

concentrations they form a nearly rigid porous glass through which the fluid permeates. The theoretically determined pressure drop is nonlinear in the diffusion regime and linear in the permeation regime, in quantitative agreement with experimental measurements

Water permeation through anion exchange membranes

Science.gov (United States)

Luo, Xiaoyan; Wright, Andrew; Weissbach, Thomas; Holdcroft, Steven

2018-01-01

An understanding of water permeation through solid polymer electrolyte (SPE) membranes is crucial to offset the unbalanced water activity within SPE fuel cells. We examine water permeation through an emerging class of anion exchange membranes, hexamethyl-p-terphenyl poly (dimethylbenzimidazolium) (HMT-PMBI), and compare it against series of membrane thickness for a commercial anion exchange membrane (AEM), Fumapem® FAA-3, and a series of proton exchange membranes, Nafion®. The HMT-PMBI membrane is found to possess higher water permeabilities than Fumapem® FAA-3 and comparable permeability than Nafion (H+). By measuring water permeation through membranes of different thicknesses, we are able to decouple, for the first time, internal and interfacial water permeation resistances through anion exchange membranes. Permeation resistances on liquid/membrane interface is found to be negligible compared to that for vapor/membrane for both series of AEMs. Correspondingly, the resistance of liquid water permeation is found to be one order of magnitude smaller compared to that of vapor water permeation. HMT-PMBI possesses larger effective internal water permeation coefficient than both Fumapem® FAA-3 and Nafion® membranes (60 and 18% larger, respectively). In contrast, the effective interfacial permeation coefficient of HMT-PMBI is found to be similar to Fumapem® (±5%) but smaller than Nafion®(H+) (by 14%).

Tritium permeation through iron

International Nuclear Information System (INIS)

Hagi, Hideki; Hayashi, Yasunori

1989-01-01

An experimental method for measuring diffusion coefficients and permeation rates of tritium in metals around room temperature has been established, and their values in iron have been obtained by using the method. Permeation rates of tritium and hydrogen through iron were measured by the electrochemical method in which a tritiated aqueous solution was used as a cathodic electrolyte. Tritium and hydrogen were introduced from one side of a membrane specimen by cathodic polarization, while at the other side of the specimen the permeating tritium and hydrogen were extracted by potentiostatical ionization. The amount of permeated hydrogen was obtained by integrating the anodic current, and that of tritium was determined by measuring the radioactivity of the electrolyte sampled from the extraction side. Diffusion coefficients of tritium (D T ) and hydrogen (D H ) were determined from the time lag of tritium and hydrogen permeation. D T =9x10 -10 m 2 /s and D H =4x10 -9 m 2 /s at 286 K for annealed iron specimens. These values of D T and D H were compared with the previous data of the diffusion coefficients of hydrogen and deuterium, and the isotope effect in diffusion was discussed. (orig.)

Tritium permeation in fusion reactors: INTOR

International Nuclear Information System (INIS)

Baskes, M.I.; Bauer, W.; Kerst, R.A.; Swansiger, W.A.; Wilson, K.L.

1981-12-01

Tritium permeation through the first wall of advanced fusion reactors is examined. A fraction of the D-T which bombards the first wall as charge exchange neutral particles will permeate through the first wall and enter the coolant. Calculations of the steady state permeation rate for the US INTOR Tokamak design result in values of less than or equal to 0.002 grams of tritium per day under the most favorable conditions. For unfavorable surface conditions the rate is greater than or equal to 0.1 g/day. The magnitude of these permeation rates is critically dependent on the temperatures and surface conditions of the wall. The introduction of permeation barriers at the wall-coolant interface can significantly reduce permeation rates and hence may be desirable for reactor applications

Permeation behavior of deuterium implanted into beryllium

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Hirofumi; Hayashi, Takumi; O' hira, Shigeru; Nishi, Masataka [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2001-09-01

Study on Implantation Driven Permeation (IDP) behavior of deuterium through pure beryllium was investigated as a part of the research to predict the tritium permeation through the first wall components ITER (International Thermonuclear Experimental Reactor). The permeation experiments were carried out with two beryllium specimens, one was an unannealed specimen and the other was that annealed at 1173 K. The permeation flux was measured as a function of specimen temperature and incident ion flux. Surface analysis of specimen was also carried out after the permeation experiment. Permeation was observed only with the annealed specimen and no significant permeation was observed with unannealed specimen under the present experimental condition (maximum temperature: 685 K, detection limit: 1x10{sup 13} D atoms/m{sup 2}s). It could be attributed that the intrinsic lattice defects, which act as diffusion preventing site, decreased with the specimen annealing. Based on the result of steady and transient permeation behavior and surface analysis, it was estimated that the deuterium permeation implanted into annealed beryllium was controlled by surface recombination due to the oxide layer on the surface of the permeated side. (author)

Flibe-D2 Permeation Experiment and Analysis

International Nuclear Information System (INIS)

Fukada, S.; Anderl, R.A.; Pawelko, R.J.; Smolik, G.R.; Schuetz, S.T.; O'Brien, J.E.; Nishimura, H.; Hatano, Y.; Terai, T.; Petti, D.A.; Sze, D.-K.; Tanaka, S.

2003-01-01

Experiment of D 2 permeation through Ni facing with purified Flibe is being carried out under the Japan-US joint research project (JUPITER-II). The experiment is proceeding in the following phases; (i) fabrication and assembly of a dual-probe permeation apparatus, (ii) a single-probe Ni/D 2 permeation experiment without Flibe, (iii) a dual-probe Ni/D 2 permeation experiment without Flibe, (iv) Flibe chemical purification by HF/H 2 gas bubbling, (v) physical purification by Flibe transport through a porous Ni filter, (vi) Ni/Flibe/D 2 permeation experiment, and (vii) Ni/Flibe/HT permeation experiment. The present paper describes results of the single and dual Ni/D 2 permeation experiments in detail

Electrodynamic thermogravimetric analyzer

International Nuclear Information System (INIS)

Spjut, R.E.; Bar-Ziv, E.; Sarofim, A.F.; Longwell, J.P.

1986-01-01

The design and operation of a new device for studying single-aerosol-particle kinetics at elevated temperatures, the electrodynamic thermogravimetric analyzer (EDTGA), was examined theoretically and experimentally. The completed device consists of an electrodynamic balance modified to permit particle heating by a CO 2 laser, temperature measurement by a three-color infrared-pyrometry system, and continuous weighing by a position-control system. In this paper, the position-control, particle-weight-measurement, heating, and temperature-measurement systems are described and their limitations examined

Thermogravimetric investigations of vanadium complexes

International Nuclear Information System (INIS)

Bechmann, W.; Uhlemann, E.; Ludwig, W.

1987-01-01

Extensive studies on oxovanadium(IV) and (V) complexes with bidentate chelating ligands include thermogravimetric investigations. TG, DTG, and DTA data provide additional facts to redox behaviour and stability of the complexes. These data also allow a critical appreciation of the given melting temperatures. (author)

On Diffusion and Permeation

KAUST Repository

Peppin, Stephen S. L.

2009-01-01

Diffusion and permeation are discussed within the context of irreversible thermodynamics. A new expression for the generalized Stokes-Einstein equation is obtained which links the permeability to the diffusivity of a two-component solution and contains the poroelastic Biot-Willis coefficient. The theory is illustrated by predicting the concentration and pressure profiles during the filtration of a protein solution. At low concentrations the proteins diffuse independently while at higher concentrations they form a nearly rigid porous glass through which the fluid permeates. The theoretically determined pressure drop is nonlinear in the diffusion regime and linear in the permeation regime, in quantitative agreement with experimental measurements. © 2009 Walter de Gruyter, Berlin, New York.

Thermogravimetric assessment of thermal degradation in asphaltenes

Energy Technology Data Exchange (ETDEWEB)

Barneto, Agustín García, E-mail: agustin.garcia@diq.uhu.es [Department of Chemical Engineering, Physical Chemistry and Organic Chemistry, University of Huelva, Huelva (Spain); Carmona, José Ariza [Department of Chemical Engineering, Physical Chemistry and Organic Chemistry, University of Huelva, Huelva (Spain); Garrido, María José Franco [CEPSA, RDI Centre, Madrid (Spain)

2016-03-20

Graphical abstract: - Highlights: • Asphaltenes content of visbreaking streams in oil refinery can be measured by using TGA. • Deconvoluting TGA curves allows the thermal-based composition of asphaltenes to be elucidated. • Asphaltenes cracking involves acceleratory stages compatible with autocatalytic kinetic. • Activation energy during asphaltenes pyrolysis increased with increasing temperature. • Activation energy remained almost constant at 200–225 kJ/mol during oxidative cracking. - Abstract: Monitoring asphaltenes is very important with a view to optimizing visbreaking units in oil refineries. Current analyses based on selective dissolution in different solvents are slow, so new, more expeditious methods for measuring asphaltenes are required to facilitate fuel-oil production. In this work, we studied the thermal degradation of asphaltenes as the potential basis for a thermogravimetric method for their monitoring in visbreaking streams. The thermal degradation of asphaltenes occurs largely from 400 to 500 °C; the process is quite smooth in an inert environment but involves several fast mass loss events in the air. Kinetic parameters for characterizing the process were determined by using two model-free methods and the modified Prout–Tompkins kinetic equation to examine asphaltene thermolysis. Both types of methods showed the activation energy to increase during pyrolysis but to remain almost constant during cracking in the presence of oxygen or even diminish during char oxidation. Deconvoluting the thermogravimetric profiles revealed that asphaltene thermolysis in the air cannot be accurately described in terms of an nth order kinetic model because it involves some acceleratory phases. Also, thermogravimetric analyses of visbreaking streams revealed that char production in them is proportional to their asphaltene content. This relationship enables the thermogravimetric measurement of asphaltenes.

Thermogravimetric assessment of thermal degradation in asphaltenes

International Nuclear Information System (INIS)

Barneto, Agustín García; Carmona, José Ariza; Garrido, María José Franco

2016-01-01

Graphical abstract: - Highlights: • Asphaltenes content of visbreaking streams in oil refinery can be measured by using TGA. • Deconvoluting TGA curves allows the thermal-based composition of asphaltenes to be elucidated. • Asphaltenes cracking involves acceleratory stages compatible with autocatalytic kinetic. • Activation energy during asphaltenes pyrolysis increased with increasing temperature. • Activation energy remained almost constant at 200–225 kJ/mol during oxidative cracking. - Abstract: Monitoring asphaltenes is very important with a view to optimizing visbreaking units in oil refineries. Current analyses based on selective dissolution in different solvents are slow, so new, more expeditious methods for measuring asphaltenes are required to facilitate fuel-oil production. In this work, we studied the thermal degradation of asphaltenes as the potential basis for a thermogravimetric method for their monitoring in visbreaking streams. The thermal degradation of asphaltenes occurs largely from 400 to 500 °C; the process is quite smooth in an inert environment but involves several fast mass loss events in the air. Kinetic parameters for characterizing the process were determined by using two model-free methods and the modified Prout–Tompkins kinetic equation to examine asphaltene thermolysis. Both types of methods showed the activation energy to increase during pyrolysis but to remain almost constant during cracking in the presence of oxygen or even diminish during char oxidation. Deconvoluting the thermogravimetric profiles revealed that asphaltene thermolysis in the air cannot be accurately described in terms of an nth order kinetic model because it involves some acceleratory phases. Also, thermogravimetric analyses of visbreaking streams revealed that char production in them is proportional to their asphaltene content. This relationship enables the thermogravimetric measurement of asphaltenes.

Permeation of hair dye ingredients, p-phenylenediamine and aminophenol isomers, through protective gloves.

Science.gov (United States)

Lee, Hsiao-Shu; Lin, Yu-Wen

2009-04-01

Skin irritation and contact allergies are skin disorders common to hairdressers. The predominant oxidative hair dye components, such as p-phenylenediamine (PPD) and aminophenol isomers, can cause contact dermatitis. Use of protective gloves can prevent dermal contact with skin irritants. This study investigates the permeation behaviors of p-aminophenol (PAP), m-aminophenol (MAP), o-aminophenol (OAP) and PPD in single and mixed challenge solutions with disposable natural rubber latex (NRL) gloves, disposable polyvinylchloride (PVC) gloves and neoprene (NP) gloves. The challenge solutions were 4% PPD (w/v), 3% OAP (w/v), 2% PAP (w/v) and 2% MAP (w/v) in ethanol or 12% hydrogen peroxide solutions. The cocktail solutions of the four chemicals were also tested. An American Society for Testing and Materials type permeation cell, ethanol liquid collection and gas chromatography-flame ionization detection of samples taken from the collection medium every 10 min facilitated determination of breakthrough times (BTs), cumulative permeated masses and steady-state permeation rates (SSPRs). Experiments were 4 h long for the NRL and PVC gloves and 8 h for NP gloves. No chemicals tested broke through the NP gloves when exposed for 8 h. In the ethanol solution, PPD and OAP started breaking through the PVC gloves at 40 min. The SSPRs of PVC gloves were higher than those for NRL gloves in all challenge conditions for both single chemicals and mixtures. No tested chemicals in hydrogen peroxide solutions permeated the gloves during the 4-h tests. The chemical composition of the challenge solution was a main effecter of BTs and SSPRs for the NRL glove. For disposable PVC gloves, the main factors of BTs were molecular size [molar volume (MV)] and polarity (logK(ow)), and the primary factors of SSPRs were concentration, MV and logK(ow). In conclusion, disposable NRL gloves and disposable PVC gloves should not be used repeatedly for handling the hair dye products. Hydrogen peroxide did not

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of semivolatile organic compounds in bottom sediment by solvent extraction, gel permeation chromatographic fractionation, and capillary-column gas chromatography/mass spectrometry

Science.gov (United States)

Furlong, E.T.; Vaught, D.G.; Merten, L.M.; Foreman, W.T.; Gates, Paul M.

1996-01-01

A method for the determination of 79 semivolatile organic compounds (SOCs) and 4 surrogate compounds in soils and bottom sediment is described. The SOCs are extracted from bottom sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography (GPC). The SOCs then are qualitatively identified and quantitative concentrations determined by capillary-column gas chromatography/mass spectrometry (GC/MS). This method also is designed for an optional simultaneous isolation of polychlorinated biphenyls (PCBs) and organochlorine (OC) insecticides, including toxaphene. When OCs and PCBs are determined, an additional alumina- over-silica column chromatography step follows GPC cleanup, and quantitation is by dual capillary- column gas chromatography with electron-capture detection (GC/ECD). Bottom-sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethane. The extract is concentrated, centrifuged, and then filtered through a 0.2-micrometer polytetrafluoro-ethylene syringe filter. Two aliquots of the sample extract then are quantitatively injected onto two polystyrene- divinylbenzene GPC columns connected in series. The SOCs are eluted with dichloromethane, a fraction containing the SOCs is collected, and some coextracted interferences, including elemental sulfur, are separated and discarded. The SOC-containing GPC fraction then is analyzed by GC/MS. When desired, a second aliquot from GPC is further processed for OCs and PCBs by combined alumina-over-silica column chromatography. The two fractions produced in this cleanup then are analyzed by GC/ECD. This report fully describes and is limited to the determination of SOCs by GC/MS.

Comparison of solid phase extraction, saponification and gel permeation chromatography for the clean-up of microwave-assisted biological extracts in the analysis of polycyclic aromatic hydrocarbons.

Science.gov (United States)

Navarro, P; Cortazar, E; Bartolomé, L; Deusto, M; Raposo, J C; Zuloaga, O; Arana, G; Etxebarria, N

2006-09-22

The feasibility of different clean-up procedures was studied for the determination of polycyclic aromatic hydrocarbons (PAHs) in biota samples such as oysters, mussels and fish liver. In this sense, once the samples were extracted--essentially with acetone and in a microwave system--and before they could be analysed by gas chromatography-mass spectrometry (GC-MS), three different approaches were studied for the clean-up step: solid phase extraction (SPE), microwave-assisted saponification (MAS) and gel permeation chromatography (GPC). The main aim of this work was to maximise the recoveries of PAHs and to minimise the presence of interfering compounds in the last extract. In the case of SPE, Florisil cartridges of 1, 2 and 5 g, and silica cartridges of 5 g were studied. In that case, and with oysters and mussels, microwave-assisted extraction and 5 g Florisil cartridges provided good results. In addition, the concentrations obtained for Standard Reference Material (SRM) NIST 2977 (mussel tissue) were in good agreement with the certified values. In the case of microwave-assisted saponification, the extracts were not as clean as those obtained with 5 g Florisil and this fact lead to overestimate the concentration of the heaviest PAHs. Finally, the cleanest extracts were obtained by GPC. The method was successfully applied to mussels, oysters and hake liver, and the results obtained for NIST 2977 (mussel tissue) were within the confidence interval of the certified reference material for most of the certified analytes.

Permeation of Telone EC through protective gloves.

Science.gov (United States)

Zainal, Hanaa; Que Hee, Shane S

2005-09-30

Telone is a potent fumigant that is based on the chlorinated unsaturated hydrocarbon, 1,3-dichloropropene (1,3-DCP). It is often applied without dilution and so poses severe inhalation and air pollution threats. Urinary metabolites of 1,3-DCP have been detected after Telone skin exposure, so that preventing dermal exposure is also important. The objective of the study was to assess if nitrile and multi-layer ("laminated") gloves provide adequate protection against Telone EC formulation. To accomplish this, disposable (Safeskin) and chemically resistant (Sol-Vex) nitrile and laminated (Barrier mark and Silver Shield) glove materials were challenged by Telone EC with hexane liquid collection in an ASTM-type I-PTC-600 permeation cell. Analyses of cis- and trans-1,3-DCP in the collection fluid at specified times were performed on a moderately polar capillary column by gas chromatography-electron capture detection. Telone EC caused microholes in both nitrile materials, though the chemically protective material was degraded slower than the disposable nitrile. The laminated gloves offered limited protection. Silver Shield protected best because 1.5-2.3 mg 1,3-DCP permeated by 8 h relative to 2.5-7.6 mg for Barrier, implying about 2.5 times more protection for 8 h. Even for Silver Shield, the extent of protection was inadequate as illustrated by a risk assessment of the skin exposure situation. The normalized breakthrough times for both types of laminated gloves varied between 27 and 60 min. It is recommended that Viton gloves still be worn for protection.

Contribution made by multivariate curve resolution applied to gel permeation chromatography-Fourier transform infrared data for an in-depth characterization of styrene-butadiene rubber blends.

Science.gov (United States)

Ruckebusch, C; Vilmin, F; Coste, N; Huvenne, J P

2008-07-01

We evaluate the contribution made by multivariate curve resolution-alternating least squares (MCR-ALS) for resolving gel permeation chromatography-Fourier transform infrared (GPC-FT-IR) data collected on butadiene rubber (BR) and styrene butadiene rubber (SBR) blends in order to access in-depth knowledge of polymers along the molecular weight distribution (MWD). In the BR-SBR case, individual polymers differ in chemical composition but share almost the same MWD. Principal component analysis (PCA) gives a general overview of the data structure and attests to the feasibility of modeling blends as a binary system. MCR-ALS is then performed. It allows resolving the chromatographic coelution and validates the chosen methodology. For SBR-SBR blends, the problem is more challenging since the individual elastomers present the same chemical composition. Rank deficiency is detected from the PCA data structure analysis. MCR-ALS is thus performed on column-wise augmented matrices. It brings very useful insight into the composition of the analyzed blends. In particular, a weak change in the composition of individual SBR in the MWD's lowest mass region is revealed.

Fermentation of lactose to ethanol in cheese whey permeate and concentrated permeate by engineered Escherichia coli.

Science.gov (United States)

Pasotti, Lorenzo; Zucca, Susanna; Casanova, Michela; Micoli, Giuseppina; Cusella De Angelis, Maria Gabriella; Magni, Paolo

2017-06-02

Whey permeate is a lactose-rich effluent remaining after protein extraction from milk-resulting cheese whey, an abundant dairy waste. The lactose to ethanol fermentation can complete whey valorization chain by decreasing dairy waste polluting potential, due to its nutritional load, and producing a biofuel from renewable source at the same time. Wild type and engineered microorganisms have been proposed as fermentation biocatalysts. However, they present different drawbacks (e.g., nutritional supplements requirement, high transcriptional demand of recombinant genes, precise oxygen level, and substrate inhibition) which limit the industrial attractiveness of such conversion process. In this work, we aim to engineer a new bacterial biocatalyst, specific for dairy waste fermentation. We metabolically engineered eight Escherichia coli strains via a new expression plasmid with the pyruvate-to-ethanol conversion genes, and we carried out the selection of the best strain among the candidates, in terms of growth in permeate, lactose consumption and ethanol formation. We finally showed that the selected engineered microbe (W strain) is able to efficiently ferment permeate and concentrated permeate, without nutritional supplements, in pH-controlled bioreactor. In the conditions tested in this work, the selected biocatalyst could complete the fermentation of permeate and concentrated permeate in about 50 and 85 h on average, producing up to 17 and 40 g/l of ethanol, respectively. To our knowledge, this is the first report showing efficient ethanol production from the lactose contained in whey permeate with engineered E. coli. The selected strain is amenable to further metabolic optimization and represents an advance towards efficient biofuel production from industrial waste stream.

Measuring the molecular dimensions of wine tannins: comparison of small-angle X-ray scattering, gel-permeation chromatography and mean degree of polymerization.

Science.gov (United States)

McRae, Jacqui M; Kirby, Nigel; Mertens, Haydyn D T; Kassara, Stella; Smith, Paul A

2014-07-23

The molecular size of wine tannins can influence astringency, and yet it has been unclear as to whether the standard methods for determining average tannin molecular weight (MW), including gel-permeation chromatography (GPC) and depolymerization reactions, are actually related to the size of the tannin in wine-like conditions. Small-angle X-ray scattering (SAXS) was therefore used to determine the molecular sizes and corresponding MWs of wine tannin samples from 3 and 7 year old Cabernet Sauvignon wine in a variety of wine-like matrixes: 5-15% and 100% ethanol; 0-200 mM NaCl and pH 3.0-4.0, and compared to those measured using the standard methods. The SAXS results indicated that the tannin samples from the older wine were larger than those of the younger wine and that wine composition did not greatly impact on tannin molecular size. The average tannin MWs as determined by GPC correlated strongly with the SAXS results, suggesting that this method does give a good indication of tannin molecular size in wine-like conditions. The MW as determined from the depolymerization reactions did not correlate as strongly with the SAXS results. To our knowledge, SAXS measurements have not previously been attempted for wine tannins.

Pb-H2O Thermogravimetric Plants. The Rankine Cycle

International Nuclear Information System (INIS)

Arosio, S.; Carlevaro, R.

2000-01-01

An economic evaluation concerning Pb-H 2 O thermogravimetric systems with an electric power in the range 200-1.000 kW has been done. Moreover, plant and running costs for a thermogravimetric and a Rankine cycle, 1 MW power, have been compared. Basically due to the lead charge, the plant cost of the former is higher: nevertheless such amount can be recuperated in less than three years, being higher the running cost of the latter [it

Thermogravimetric analysis and dissociation pressure of caesium trihalides

International Nuclear Information System (INIS)

Harris, G.S.; McKechnie, J.S.

1982-01-01

We have carried out a thermogravimetric study of caesium trihalides to obtain, from the procedural decomposition temperatures, an order of apparent thermal stability which could be compared with the order of thermodynamic stability obtained from vapour pressure measurements. Thermogravimetric analysis could also prove to be a useful method for rapid analysis of metal polyhalides. The thermograms indicated a one-step decomposition for each compound; the procedural decomposition temperatures and percentage weight losses obtained are given. Dissociation pressures were measured and values of equilibrium constant and enthalpy of dissociation were calculated. The results are given. The 'stability' order obtained is discussed. (U.K.)

Thermogravimetric-quadrupole mass-spectrometric analysis of geochemical samples.

Science.gov (United States)

Gibson, E. K., Jr.; Johnson, S. M.

1972-01-01

Thermogravimetric-quadrupole mass-spectrometric-analysis techniques can be used to study a wide variety of problems involving decomposition processes and identification of released volatile components. A recording vacuum thermoanalyzer has been coupled with a quadrupole mass spectrometer. The rapid scan capabilities of the quadrupole mass spectrometer are used to identify the gaseous components released. The capability of the thermogravimetric-quadrupole mass spectrometer to provide analytical data for identification of the released volatile components, for determination of their sequence of release and for correlation of thermal-decomposition studies is illustrated by an analysis of the Orgueil carbonaceous chondrite.

Counter-diffusion and -permeation of deuterium and hydrogen through metals

Energy Technology Data Exchange (ETDEWEB)

Kizu, Kaname; Tanabe,; Tetsuo, [Nagoya Univ. (Japan)

1998-03-01

The first experiments for counter-diffusion and -permeation of deuterium and hydrogen through palladium were performed. Deuterium permeation rates against D{sub 2} pressure were measured under the condition where hydrogen permeated to opposite direction by supplying H{sub 2} gas at the permeated side of D{sub 2}. It was found that not a small amount of deuterium was clearly permeated even if the deuterium pressure was much smaller than the hydrogen pressure. Deuterium permeation rate was gradually reduced by increasing the counter H permeation. The deuterium permeation rate under the counter H permeation is well represented by a simple model in which the ratio of the deuterium permeation rates with and without the counter H permeation was proportional to the fractional concentration of deuterium in the bulk. As increasing the hydrogen counter flow, however, the deuterium permeation rate deviates from the model. This means that adsorption (absorption) of D{sub 2} from gas phase is inhibited and surface recombination of deuterium is blocked by hydrogen. (author)

Evaluation of co-pyrolysis petrochemical wastewater sludge with lignite in a thermogravimetric analyzer and a packed-bed reactor: Pyrolysis characteristics, kinetics, and products analysis.

Science.gov (United States)

Mu, Lin; Chen, Jianbiao; Yao, Pikai; Zhou, Dapeng; Zhao, Liang; Yin, Hongchao

2016-12-01

Co-pyrolysis characteristics of petrochemical wastewater sludge and Huolinhe lignite were investigated using thermogravimetric analyzer and packed-bed reactor coupled with Fourier transform infrared spectrometer and gas chromatography. The pyrolysis characteristics of the blends at various sludge blending ratios were compared with those of the individual materials. Thermogravimetric experiments showed that the interactions between the blends were beneficial to generate more residues. In packed-bed reactor, synergetic effects promoted the release of gas products and left less liquid and solid products than those calculated by additive manner. Fourier transform infrared spectrometer analysis showed that main functional groups in chars gradually disappeared with pyrolysis temperatures increasing, and H 2 O, CH 4 , CO, and CO 2 appeared in volatiles during pyrolysis. Gas compositions analysis indicated that, the yields of H 2 and CO clearly increased as the pyrolysis temperature and sludge blending ratio increasing, while the changes of CH 4 and CO 2 yields were relatively complex. Copyright © 2016 Elsevier Ltd. All rights reserved.

Thermogravimetric study of vinpocetine suppository

Directory of Open Access Journals (Sweden)

N. А. Nаgоrnaya

2014-02-01

Full Text Available Introduction. Development of technology is the one of the main stage in creation of new medications. Technological process of suppository manufacturing includes sufficiently long thermoprocessing during suppository base making, addition of the active substances and homogenisation. This makes risk of chemical and physical transformations of active substances and excipients in suppository which can be destroyed and changed pharmacologicaly. Use of thermogravimetric analyses in pharmaceutical technology allows to study possibility of chemical interactions of components in the wide range of temperature. The aim of this work was to study thermoprocessing effects on suppository base with vinpocetine in temperature range of technological process of suppository manufacturing. Object. Vinpocetine rectal suppository (with 0,5% of surface-active substances, active substance (vinpocetine and excipients (twin 80, cacao oil were used as the objects of thermogravimetric investigation. Thermogravimetric analyses was carried out on the derivatograph «Shimadzu DTG-60» (Japan with the platinum-rhodium thermocouple by heating from 25°C to 200°C in the aluminium crucible. α-Al2O3 was used as standard. Heating speed was 10ºС in minute. Model mass was 14,23 – 34,4 mg. Conclusions. It was established that cacao oil is thermolabile substance with melting temperature 41,32 ºС. Surface-active substance twin 80 displays thermostability from 30 tо 100ºС. Vinpocetine derivatogramme confirmed its thermostability in temperature range from 30 tо 154 ºС. Derivatogramme of vinpocetine rectal suppository 0,01 and suppository base displayed the absence of critical temperature lower 100ºС. Insignificant mass loss (0,21% shows that fact. Investigation of composition over 100ºС wasn’t carried out because these temperatures aren’t used in technological process of suppository manufacturing. Presence of thermal effects on derivatogramme of vinpocetine rectal

In-site coatings to reduce H and Tr permeation

International Nuclear Information System (INIS)

Stoever, D.; Buchkremer, H.P.; Hecker, R.; Jonas, H.; Schaefer, J.; Zink, U.; Forsyth, N.; Thiele, W.

1982-01-01

The main goal of this project is the development of protective coatings to reduce or prevent Tr and H permeation through the heat exchanger walls of HTR components. The tasks of the project are: Measurement of the permeation inhibition efficiency of oxidic coatings on the high-temperature- resistant heat exchanger walls; establishing the parameters influencing permeation by variation of the process gas and steam parameters, temperature and mechanical stress; characterisation of coatings and correlation of coating characteristics with permeation measurements; investigation of permeation and corrosion mechanisms; quantitative description of H and Tr permeation by means of mathematical/physical models. (orig./IHOE) [de

Permeation of gasoline, diesel, bioethanol (E85), and biodiesel (B20) fuels through six glove materials.

Science.gov (United States)

Chin, Jo-Yu; Batterman, Stuart A

2010-07-01

Biofuels and conventional fuels differ in terms of their evaporation rates, permeation rates, and exhaust emissions, which can alter exposures of workers, especially those in the fuel refining and distribution industries. This study investigated the permeation of biofuels (bioethanol 85%, biodiesel 20%) and conventional petroleum fuels (gasoline and diesel) through gloves used in occupational settings (neoprene, nitrile, and Viton) and laboratories (latex, nitrile, and vinyl), as well as a standard reference material (neoprene sheet). Permeation rates and breakthrough times were measured using the American Society for Testing and Materials F739-99 protocol, and fuel and permeant compositions were measured by gas chromatography/mass spectrometry. In addition, we estimated exposures for three occupational scenarios and recommend chemical protective clothing suitable for use with motor fuels. Permeation rates and breakthrough times depended on the fuel-glove combination. Gasoline had the highest permeation rate among the four fuels. Bioethanol (85%) had breakthrough times that were two to three times longer than gasoline through neoprene, nitrile Sol-Vex, and the standard reference materials. Breakthrough times for biodiesel (20%) were slightly shorter than for diesel for the latex, vinyl, nitrile examination, and the standard neoprene materials. The composition of permeants differed from neat fuels, e.g., permeants were significantly enriched in the lighter aromatics including benzene. Viton was the best choice among the tested materials for the four fuels tested. Among the scenarios, fuel truck drivers had the highest uptake via inhalation based on the personal measurements available in the literature, and gasoline station attendants had highest uptake via dermal exposure if gloves were not worn. Appropriate selection and use of gloves can protect workers from dermal exposures; however, current recommendations from the National Institute for Occupational Safety and

Lyophilized phytosomal nanocarriers as platforms for enhanced diosmin delivery: optimization and ex vivo permeation

Directory of Open Access Journals (Sweden)

Freag MS

2013-07-01

Full Text Available May S Freag, Yosra SR Elnaggar, Ossama Y AbdallahDepartment of Pharmaceutics, Faculty of Pharmacy, Alexandria University, Alexandria, EgyptAbstract: Diosmin (DSN is an outstanding phlebotonic flavonoid with a tolerable potential for the treatment of colon and hepatocellular carcinoma. Being highly insoluble, DSN bioavailability suffers from high inter-subject variation due to variable degrees of permeation. This work endeavored to develop novel DSN loaded phytosomes in order to improve drug dissolution and intestinal permeability. Three preparation methods (solvent evaporation, salting out, and lyophilization were compared. Nanocarrier optimization encompassed different soybean phospholipid (SPC types, different solvents, and different DSN:SPC molar ratios (1:1, 1:2, and 1:4. In vitro appraisal encompassed differential scanning calorimetry, infrared spectroscopy, particle size, zeta potential, polydispersity index, transmission electron microscopy, drug content, and in vitro stability. Comparative dissolution studies were performed under sink versus non-sink conditions. Ex vivo intestinal permeation studies were performed on rats utilizing noneverted sac technique and high-performance liquid chromatography analysis. The results revealed lyophilization as the optimum preparation technique using SPC and solvent mixture (Dimethyl sulphoxide:t-butylalchol in a 1:2 ratio. Complex formation was contended by differential scanning calorimetry and infrared data. Optimal lyophilized phytosomal nanocarriers (LPNs exhibited the lowest particle size (316 nm, adequate zeta-potential (−27 mV, and good in vitro stability. Well formed, discrete vesicles were revealed by transmission electron microscopy, drug content, and in vitro stability. Comparative dissolution studies were performed. LPNs demonstrated significant enhancement in DSN dissolution compared to crude drug, physical mixture, and generic and brand DSN products. Permeation studies revealed 80% DSN

Proton exchange membranes from sulfonated polyetheretherketone and sulfonated polyethersulfone-cardo blends: Conductivity, water sorption and permeation properties

International Nuclear Information System (INIS)

Li, Yongli; Nguyen, Quang Trong; Schaetzel, Pierre; Lixon-Buquet, Camille; Colasse, Laurent; Ratieuville, Vincent

2013-01-01

Five blend membranes were prepared by solvent evaporation from solutions of the synthesized sulfonated polyetheretherketone (SPEEK) and sulfonated polyethersulfone-cardo (SPESc). Their ion exchange capacity and degree of sulfonation determined by acid–base titration and by thermogravimetric analysis were consistent. The blends glass transition behavior obtained by differential scanning calorimetry suggests that the two sulfonated polymers are compatible in the whole composition range. The values of the activation energy for proton transport determined by conductivity measurements on the SPEEK-based blend membranes were in the range of 13–34 kJ mol −1 , which suggest a mixed transport mechanism that involves both proton jumps on ionic sites and water of hydration and diffusion of proton–water complex in hydrophilic domains. The water vapor sorption in the membranes exhibits sigmoid-shape isotherms which were well fitted by the “new dual mode sorption” model, and the fitted parameters values were successfully used to model the change in the water permeation flux with the upstream water activity using the first Fick's diffusion equation. The fast increase in the permeation flux beyond a critical value of activity (0.5) was owing to the exponential concentration-dependent diffusion coefficient. These modelings allowed us to show a strong increase in the limit diffusion coefficient of water and a decrease in the water-diffusion plasticization coefficient with the SPEEK content in the polymer blends

Implantation driven permeation behavior of deuterium through pure tungsten

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Hirofumi E-mail: nakamura@tpl.tokai.jaeri.go.jp; Hayashi, Takumi; Nishi, Masataka; Arita, Makoto; Okuno, Kenji

2001-09-01

Implantation driven permeation behavior of deuterium through pure tungsten has been investigated to estimate the amount of tritium permeation through its barrier in a thermo-nuclear fusion device. The permeation experiments were performed on pure tungsten foil of 25 {mu}m thickness under conditions of incident flux of 1.9x10{sup 18}-1.1x10{sup 19} D{sup +}/m{sup 2}s, incident ion energy of 200-2000 eV, and specimen temperature of 512-660 K. As a result of this steady-state permeation experiment, the rate-determining process of deuterium permeation was found to be controlled by diffusion at both implanted and permeated sides. On the other hand, transient permeation was strongly affected by trap effect in the specimen. Simulation analysis using TMAP code on transient permeation behavior indicates the existence of a trap site with a trap energy of nearly 1eV and with a trap density of over several ten's ppm in tungsten.

Implantation driven permeation behavior of deuterium through pure tungsten

International Nuclear Information System (INIS)

Nakamura, Hirofumi; Hayashi, Takumi; Nishi, Masataka; Arita, Makoto; Okuno, Kenji

2001-01-01

Implantation driven permeation behavior of deuterium through pure tungsten has been investigated to estimate the amount of tritium permeation through its barrier in a thermo-nuclear fusion device. The permeation experiments were performed on pure tungsten foil of 25 μm thickness under conditions of incident flux of 1.9x10 18 -1.1x10 19 D + /m 2 s, incident ion energy of 200-2000 eV, and specimen temperature of 512-660 K. As a result of this steady-state permeation experiment, the rate-determining process of deuterium permeation was found to be controlled by diffusion at both implanted and permeated sides. On the other hand, transient permeation was strongly affected by trap effect in the specimen. Simulation analysis using TMAP code on transient permeation behavior indicates the existence of a trap site with a trap energy of nearly 1eV and with a trap density of over several ten's ppm in tungsten

Thermogravimetric and kinetic study of methylolmelamine ...

African Journals Online (AJOL)

Some salient properties of cotton cellulose which requires it to be treated with additives to improve its versatility were examined taken into consideration, the molecular structure. Thermogravimetric analysis of the cotton fabric and the treated cotton fabric were carried out in an improvised muffled furnace. The result was in ...

Permeation of hydrogen through metal membranes

International Nuclear Information System (INIS)

Wienhold, P.; Rota, E.; Waelbroeck, F.; Winter, J.; Banno, Tatsuya.

1986-08-01

Experiments show that the permeant flux of hydrogen through a metal membrane at low driving pressures ( r is introduced into the model as a new material constant and the rate equations are given. After the description of the wall pump effect, a variety of different limiting cases are discussed for a symmetrical permeation membrane. This is modified to the asymmetric case and to the influence of particle implantation. The permeation number W turns out to be a dimensionless quantity which characterizes the permeation range and predicts the permeant flux in steady state. (orig.)

Formulation of sage essential oil (Salvia officinalis, L.) monoterpenes into chitosan hydrogels and permeation study with GC-MS analysis.

Science.gov (United States)

Kodadová, Alexandra; Vitková, Zuzana; Herdová, Petra; Ťažký, Anton; Oremusová, Jarmila; Grančai, Daniel; Mikuš, Peter

2015-01-01

This study deals with the formulation of natural drugs into hydrogels. For the first time, compounds from the sage essential oil were formulated into chitosan hydrogels. A sample preparation procedure for hydrophobic volatile analytes present in a hydrophilic water matrix along with an analytical method based on the gas chromatography coupled with the mass spectrometry (GC-MS) was developed and applied for the evaluation of the identity and quantity of essential oil components in the hydrogels and saline samples. The experimental results revealed that the chitosan hydrogels are suitable for the formulation of sage essential oil. The monoterpene release can be effectively controlled by both chitosan and caffeine concentration in the hydrogels. Permeation experiment, based on a hydrogel with the optimized composition [3.5% (w/w) sage essential oil, 2.0% (w/w) caffeine, 2.5% (w/w) chitosan and 0.1% (w/w) Tween-80] in donor compartment, saline solution in acceptor compartment, and semi-permeable cellophane membrane, demonstrated the useful permeation selectivity. Here, (according to lipophilicity) an enhanced permeation of the bicyclic monoterpenes with antiflogistic and antiseptic properties (eucalyptol, camphor and borneol) and, at the same time, suppressed permeation of toxic thujone (not exceeding its permitted applicable concentration) was observed. These properties highlight the pharmaceutical importance of the developed chitosan hydrogel formulating sage essential oil in the dermal applications.

Permeation Tests on Polypropylene Fiber Materials

Science.gov (United States)

2018-03-16

Permeation Tests on Polypropylene Fiber Materials Brandy J. White Martin H. Moore Brian J. Melde Laboratory for the Study of Molecular Interfacial...ABSTRACT Permeation Tests on Polypropylene Fiber Materials Brandy J. White, Martin H. Moore, Brian J. Melde Center for Bio/Molecular Science

Spectroscopic and thermogravimetric study of nickel sulfaquinoxaline complex

International Nuclear Information System (INIS)

Tailor, Sanjay M.; Patel, Urmila H.

2016-01-01

The ability of sulfaquinoxaline (4-Amino-N-2-quinoxalinylbenzenesulfonamide) to form metal complexes are investigated. The nickel complex of sulfaquinoxaline is prepared by reflux method and characterized by CHN analysis and IR spectra. The results of IR spectral data suggest that the binding of nickel atom to the sulfonamidic nitrogen are in good agreement. The thermogravimetric analysis (TGA), differential thermal analysis (DTA) and differential thermogravimetric (DTG) analysis of nickel sulfaquinoxaline are carried out from ambient temperature to 750°C in inert nitrogen atmosphere. The activation energy, enthalpy, entropy and Gibbs free energy of nickel sulfaquinoxaline complex is determined from the thermal curves using Broido method. The results are reported in this paper.

In situ measurement of tritium permeation through stainless steel

Science.gov (United States)

Luscher, Walter G.; Senor, David J.; Clayton, Kevin K.; Longhurst, Glen R.

2013-06-01

The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a 4He carrier gas mixed with a specified quantity of tritium (T2) to yield partial pressures of 0.1, 5, and 50 Pa at 292 °C and 330 °C. In situ tritium permeation measurements were made by passing a He-Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. Results from in situ permeation measurements were compared with predictions based on an ex-reactor permeation correlation in the literature. In situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure over the ranges considered in this study. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of 3He to T, was also evaluated by introducing a 4He carrier gas mixed with 3He at a partial pressure of 1013 Pa at 330 °C. Less than 3% of the tritium resulting from 3He transmutation contributed to tritium permeation.

Thermogravimetric analysis of forest understory grasses

Science.gov (United States)

Thomas Elder; John S. Kush; Sharon M. Hermann

2011-01-01

Forest understory grasses are of significance in the initiation, establishment and maintenance of fire, whether used as a management tool or when occurring as wildfire. The fundamental thermal properties of such grasses are critical to their behavior in fire situations and have been investigated in the current work by the application of thermogravimetric analysis (TGA...

Thermogravimetric analysis of biowastes during combustion

International Nuclear Information System (INIS)

Otero, M.; Sanchez, M.E.; Gomez, X.; Moran, A.

2010-01-01

The combustion of sewage sludge (SS), animal manure (AM) and the organic fraction of municipal solid waste (OFMSW) was assessed and compared with that of a semianthracite coal (SC) and of a PET waste by thermogravimetric (TG) analysis. Differences were found in the TG curves obtained for the combustion of these materials accordingly to their respective proximate analysis. Non-isothermal thermogravimetric data were used to assess the kinetics of the combustion of these biowastes. The present paper reports on the application of the Vyazovkin model-free isoconversional method for the evaluation of the activation energy necessary for the combustion of these biowastes. The activation energy related to SS combustion (129.1 kJ/mol) was similar to that corresponding to AM (132.5 kJ/mol) while the OFMSW showed a higher value (159.3 kJ/mol). These values are quite higher than the one determined in the same way for the combustion of SC (49.2 kJ/mol) but lower than that for the combustion of a PET waste (165.6 kJ/mol).

In situ measurement of tritium permeation through stainless steel

Energy Technology Data Exchange (ETDEWEB)

Luscher, Walter G., E-mail: walter.luscher@pnnl.gov [Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99352 (United States); Senor, David J., E-mail: david.senor@pnnl.gov [Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99352 (United States); Clayton, Kevin K., E-mail: kevin.clayton@inl.gov [Idaho National Laboratory, 2525 Fremont Ave., Idaho Falls, ID 83415 (United States); Longhurst, Glen R., E-mail: glenlonghurst@suu.edu [Idaho National Laboratory, 2525 Fremont Ave., Idaho Falls, ID 83415 (United States)

2013-06-15

Highlights: ► In situ tritium permeation measurements collected over broad pressure range. ► Test conditions relevant to 316 SS in commercial light water reactors. ► Comparisons between in- and ex-reactor measurements provided. ► Correlation between tritium permeation, temperature, and pressure developed. -- Abstract: The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a {sup 4}He carrier gas mixed with a specified quantity of tritium (T{sub 2}) to yield partial pressures of 0.1, 5, and 50 Pa at 292 °C and 330 °C. In situ tritium permeation measurements were made by passing a He–Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. Results from in situ permeation measurements were compared with predictions based on an ex-reactor permeation correlation in the literature. In situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure over the ranges considered in this study. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of {sup 3}He to T, was also evaluated by introducing a {sup 4}He carrier gas mixed with {sup 3}He at a partial pressure of 1013 Pa at 330 °C. Less than 3% of the tritium resulting from {sup 3}He transmutation contributed to tritium permeation.

Tritium permeation barriers for fusion technology

International Nuclear Information System (INIS)

Perujo, A.; Forcey, K.

1994-01-01

An important issue concerning the safety, feasibility and fueling (i.e., tritium breeding ratio and recovery from the breeding blanket) of a fusion reactor is the possible tritium leakages through the structural materials and in particular through those operating at high temperatures. The control of tritium permeation could be a critical factor in determining the viability of a future fusion power reactor. The formation of tritium permeation barriers to prevent the loss of tritium to the coolant by diffusion though the structural material seems to be the most practical method to minimize such losses. Many authors have discussed the formation of permeation barriers to reduce the leakage of hydrogen isotopes through proposed first wall and structural materials. In general, there are two routes for the formation of such a barrier, namely: the growth of oxide layers (e.g., Cr 2 O 3 , Al 2 O 3 , etc.) or the application of surface coatings. Non-metals are the most promising materials from the point of view of the formation of permeation barriers. Oxides such as Al 2 O 3 or Cr 2 O 3 or carbides such as SiC or TiC have been proposed. Amongst the metals only tungsten or gold are sufficiently less permeable than steel to warrant investigation as candidate materials for permeation barriers. It is of course possible to grow oxide layers on steel directly by heating in the atmosphere or under a variety of conditions (first route above). The direct oxidizing is normally done in an environment of open-quotes wet hydrogenclose quotes to promote the growth of chromia on, for example, nickel steels or ternary oxides on 316L to prevent corrosion. The application of surface layers (second route above), offers a greater range of materials for the formation of permeation barriers. In addition to reducing permeation, such layers should be adhesive, resistant to attack by corrosive breeder materials and should not crack during thermal cycling

Hydrogen permeation properties of plasma-sprayed tungsten

International Nuclear Information System (INIS)

Anderl, R.A.; Pawelko, R.J.; Hankins, M.R.; Longhurst, G.R.; Neiser, R.A.

1994-01-01

Tungsten has been proposed as a plasma-facing component material for advanced fusion facilities. This paper reports on laboratory-scale studies that were done to assess the hydrogen permeation properties of plasma-sprayed tungsten for such applications. The work entailed deuterium permeation measurements for plasma-sprayed (PS) tungsten coatings, sputter-deposited (SP) tungsten coatings, and steel substrate material using a mass-analyzed, 3 keV D + 3 ion beam with fluxes of similar 6.5x10 19 D/m 2 s. Extensive characterization analyses for the plasma-sprayed tungsten coatings were made using Auger spectrometry and scanning electron microscopy (SEM). Observed permeation rates through composite PS-tungsten/steel specimens were several orders of magnitude below the permeation levels observed for SP-tungsten/steel composite specimens and pure steel specimens. Characterization analyses indicated that the plasma-sprayed tungsten coating had a nonhomogeneous microstructure that consisted of splats with columnar solidification, partially-melted particles with grain boundaries, and void regions. Reduced permeation levels can be attributed to the complex microstructure and a substantial surface-connected porosity. ((orig.))

Hydrogen permeation properties of plasma-sprayed tungsten

Energy Technology Data Exchange (ETDEWEB)

Anderl, R.A. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Pawelko, R.J. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Hankins, M.R. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Longhurst, G.R. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Neiser, R.A. (Sandia National Laboratories, Albuquerque, NM 87185 (United States))

1994-09-01

Tungsten has been proposed as a plasma-facing component material for advanced fusion facilities. This paper reports on laboratory-scale studies that were done to assess the hydrogen permeation properties of plasma-sprayed tungsten for such applications. The work entailed deuterium permeation measurements for plasma-sprayed (PS) tungsten coatings, sputter-deposited (SP) tungsten coatings, and steel substrate material using a mass-analyzed, 3 keV D[sup +][sub 3] ion beam with fluxes of similar 6.5x10[sup 19] D/m[sup 2] s. Extensive characterization analyses for the plasma-sprayed tungsten coatings were made using Auger spectrometry and scanning electron microscopy (SEM). Observed permeation rates through composite PS-tungsten/steel specimens were several orders of magnitude below the permeation levels observed for SP-tungsten/steel composite specimens and pure steel specimens. Characterization analyses indicated that the plasma-sprayed tungsten coating had a nonhomogeneous microstructure that consisted of splats with columnar solidification, partially-melted particles with grain boundaries, and void regions. Reduced permeation levels can be attributed to the complex microstructure and a substantial surface-connected porosity. ((orig.))

Thermal decomposition characteristics of microwave liquefied rape straw residues using thermogravimetric analysis

Science.gov (United States)

Xingyan Huang; Cornelis F. De Hoop; Jiulong Xie; Chung-Yun Hse; Jinqiu Qi; Yuzhu Chen; Feng Li

2017-01-01

The thermal decomposition characteristics of microwave liquefied rape straw residues with respect to liquefaction condition and pyrolysis conversion were investigated using a thermogravimetric (TG) analyzer at the heating rates of 5, 20, 50 °C min-1. The hemicellulose decomposition peak was absent at the derivative thermogravimetric analysis (DTG...

Tritium permeation characterization of Al{sub 2}O{sub 3}/FeAl coatings as tritium permeation barriers on 321 type stainless steel containers

Energy Technology Data Exchange (ETDEWEB)

Yang, Feilong; Xiang, Xin; Lu, Guangda; Zhang, Guikai, E-mail: zhangguikai@caep.cn; Tang, Tao; Shi, Yan; Wang, Xiaolin

2016-09-15

Accurate tritium transport properties of prospective tritium permeation barriers (TPBs) are essential to tritium systems in fusion reactors. By passing a temperature and rate-controlled sweeping gas over specimen surfaces to carry the permeated tritium to an ion chamber, the gas-driven permeation of tritium has been performed on 321 type stainless steel containers with Al{sub 2}O{sub 3}/FeAl barriers, to determine the T-permeation resistant performance and mechanism of the barrier. The tritium permeability of the Al{sub 2}O{sub 3}/FeAl coated container was reduced by 3 orders of magnitude at 500–700 °C by contrast with that of the bare one, which meets the requirement of the tritium permeation reduction factor (PRF) of TPBs for tritium operating components in the CN-HCCB TBM. The Al{sub 2}O{sub 3}/FeAl barrier resists the tritium permeation by the diffusion in the bulk substrate at a limited number of defect sites with an effective area and thickness, suggesting that the TPB quality is a very important factor for efficient T-permeation resistance. - Highlights: • T-permeation has been measured on bare and coated type 321 SS containers. • Al{sub 2}O{sub 3}/FeAl coating give a reduction of T-permeability of 3 orders of magnitude. • Mechanism of Al{sub 2}O{sub 3}/FeAl barrier resisting T-permeation has obtained. • Quality of TPB is a very important factor for efficient T-permeating reduction.

Permeation of Ionic Liquids through the skin

Directory of Open Access Journals (Sweden)

Ana Júlio

2017-12-01

Full Text Available Alternative forms of drug delivery such as delivery through the skin, have been developed to explore other routes. However, the incorporation of poorly soluble or partially insoluble drugs into these delivery systems represents a major problem. Ionic liquids (ILs may be incorporated in aqueous, oily or hydroalcoholic solutions and thus, may be used as excipients in drug delivery systems to increase/improve the topical and transdermal drug delivery. However, it is fundamental to consider the cytotoxicity of these salts and it is also crucial to evaluate if these compounds permeate through the skin. Herein, three imidazole-based ILs: [C2mim][Br], [C4mim][Br] and [C6mim][Br], were synthesized and each IL was incorporated within caffeine saturated solutions. Permeation studies of the active (caffeine in these solutions were performed to evaluate the amount of IL that permeated through the porcine ear skin in the presence of the active. To achieve this, gravimetric studies of the receptor compartment were performed. Results showed that the more lipophilic IL [C6mim][Br] presented the highest permeation through the skin. The permeation is dependent upon the size of the alkyl chain of the IL, and as more than 60% of the ILs permeate is it vital to consider the cytotoxicity of these salts when considering their incorporation in topical systems.

Hydrogen permeation resistant layers for liquid metal reactors

International Nuclear Information System (INIS)

McGuire, J.C.

1980-03-01

Reviewing the literature in the tritium diffusion field one can readily see a wide divergence in results for both the response of permeation rate to pressure, and the effect of oxide layers on total permeation rates. The basic mechanism of protective oxide layers is discussed. Two coatings which are less hydrogen permeable than the best naturally occurring oxide are described. The work described is part of an HEDL-ANL cooperative research program on Tritium Permeation in Liquid Metal Cooled Reactors. This includes permeation work on hydrogen, deuterium, and tritium with the hydrogen-deuterium research leading to the developments presented

Tritium permeation losses in HYLIFE-II heat exchanger tubes

International Nuclear Information System (INIS)

Longhurst, G.R.; Dolan, T.J.

1990-01-01

Tritium permeation through the intermediate heat exchanger of the HYLIFE-II inertial fusion design concept is evaluated for routine operating conditions. The permeation process is modelled using the Lewis analogy combined with surface recombination. It is demonstrated that at very low driving potentials, permeation becomes proportional to the first power of the driving potential. The model predicts that under anticipated conditions the primary cooling loop will pass about 6% of the tritium entering it to the intermediate coolant. Possible approached to reducing tritium permeation are explored. Permeation is limited by turbulent diffusion transport through the molten salt. Hence, surface barriers with impendance factors typical of present technology can do very little to reduce permeation. Low Flibe viscosity is desirable. An efficient tritium removal system operating on the Flibe before it gets to the intermediate heat exchanger is required. Needs for further research are highlighted. 9 refs., 2 figs., 1 tab

An unheated permeation device for calibrating atmospheric VOC measurements

Directory of Open Access Journals (Sweden)

J. Brito

2011-10-01

Full Text Available The development of an unpowered permeation device for continuous calibration of in-situ instruments measuring atmospheric volatile organic compounds (VOCs is described. Being lightweight and compact, and containing only negligible amounts of chemicals, the device is especially suited for field use such as on board aircraft. Its speciality is to maintain the permeation process in thermal equilibrium, so that the instantaneous permeation rate can be ascribed to a simple temperature measurement. This equilibrium state is maintained by a combination of three features: (i a thin PTFE membrane as permeation medium which guarantees short stabilization times, (ii a water bath as heat buffer, and (iii a vacuum-panel based insulation, in which features (ii and (iii minimize temperature drifts to ~30 mK h⁻¹ per Kelvin temperature difference to the environment. The respective uncertainty of the permeation rate due to thermal non-equilibrium is kept below 1%. An extensive theory part details the major permeation processes of gases through porous polymers, being Fick's diffusion, Knudsen flow, and viscous flow. Both the measured stabilization time and the measured temperature dependence of the permeation rate independently indicate that the permeation can be described by a viscous flow model, where diffusion of the gas molecules in large pores (having a diameter of >0.05 μm dominates.

Effect of Permeation Enhancers on the Release Behavior and ...

African Journals Online (AJOL)

Purpose: The aim of this research work was to formulate, characterize and evaluate the in vitro permeation behavior of tramadol lotion containing propylene glycol (PG) and polyethylene glycol (PEG) as permeation enhancers. Methods: The permeation experiments were conducted in vitro using full thickness rabbit skin in ...

Modeling and experiments on tritium permeation in fusion reactor blankets

Science.gov (United States)

Holland, D. F.; Longhurst, G. R.

The determination of tritium loss from helium-cooled fusion breeding blankets are discussed. The issues are: (1) applicability of present models to permeation at low tritium pressures; (2) effectiveness of oxide layers in reducing permeation; (3) effectiveness of hydrogen addition as a means to lower tritium permeation; and (4) effectiveness of conversion to tritiated water and subsequent trapping to reduce permeation. Theoretical models applicable to these issues are discussed, and results of experiments in two areas are presented; permeation of mixtures of hydrogen isotopes and conversion to tritiated water.

Modeling and experiments on tritium permeation in fusion reactor blankets

International Nuclear Information System (INIS)

Holland, D.F.; Longhurst, G.R.

1985-01-01

Issues are discussed that are critical in determining tritium loss from helium-cooled fusion breeding blankets. These issues are: (a) applicability of present models to permeation at low tritium pressures, (b) effectiveness of oxide layers in reducing permeation, (c) effectiveness of hydrogen addition as a means to lower tritium permeation, and (d) effectiveness of conversion to tritiated water and subsequent trapping as a means to reduce permeation. The paper discusses theoretical models applicable to these issues, and presents results of experiments in two areas: permeation of mixtures of hydrogen isotopes and conversion to tritiated water

PERMEATION OF POLYELECTROLYTES AND OTHER SOLUTES INTO THE PORE SPACES OF WATER-SWOLLEN CELLULOSE: A REVIEW

Directory of Open Access Journals (Sweden)

Ning Wu

2009-08-01

Full Text Available The rate and extent of transport of macromolecules and other solutes into cellulosic materials and fibers have important applications in such fields as papermaking, textiles, medicine, and chromatography. This review considers how diffusion and flow affect permeation into wood, paper, and other lignocellulosic materials. Because pore sizes within such materials can range from nanometers to millimeters, a broad perspective will be used, also considering some publications related to other porous materials. Factors that limit the rate or extent of polymer or other solute transport into pores can involve thermodynamics (affecting the driving motivation for permeation, kinetics (if there is insufficient time for the system to come to equilibrium, and physical barriers. Molecular flow is also affected by the attributes of the solute, such as molecular mass and charge, as well as those of the substrate, such as the pore size, interconnectedness, restricted areas, and surface characteristics. Published articles have helped to clarify which of these factors may have a controlling influence on molecular transport in different situations.

Measurement of skin permeation/penetration of nanoparticles for their safety evaluation.

Science.gov (United States)

Kimura, Eriko; Kawano, Yuichiro; Todo, Hiroaki; Ikarashi, Yoshiaki; Sugibayashi, Kenji

2012-01-01

The aim of the present study was to quantitatively evaluate the skin permeation/penetration of nanomaterials and to consider their penetration pathway through skin. Firstly, penetration/permeation of a model fluorescent nanoparticle, Fluoresbrite®, was determined through intact rat skin and several damaged skins. Fluoresbrite® permeated through only needle-punctured skin. The permeation profiles of soluble high molecular compounds, fluorescein isothiocyanate-dextrans (FITC-dextrans, FDs), with different molecular weights were also measured for comparison. The effects of molecular sizes and different skin pretreatments on the skin barrier were determined on the skin penetration/permeation of Fluoresbrite® and FDs. Fluoresbrite® was not permeated the intact skin, but FDs were permeated the skin. The skin distribution of titanium dioxide and zinc oxide nanoparticles was also observed after topical application of commercial cosmetics. Nanoparticles in sunscreen cosmetics were easily distributed into the groove and hair follicles after their topical application, but seldom migrated from the groove or follicles to viable epidermis and dermis. The obtained results suggested that nanoparticles did not permeate intact skin, but permeated pore-created skin. No or little permeation was observed for these nanomaterials through the stratum corneum.

Kinetic parameters from thermogravimetric analysis

Science.gov (United States)

Kiefer, Richard L.

1993-01-01

High performance polymeric materials are finding increased use in aerospace applications. Proposed high speed aircraft will require materials to withstand high temperatures in an oxidative atmosphere for long periods of time. It is essential that accurate estimates be made of the performance of these materials at the given conditions of temperature and time. Temperatures of 350 F (177 C) and times of 60,000 to 100,000 hours are anticipated. In order to survey a large number of high performance polymeric materials on a reasonable time scale, some form of accelerated testing must be performed. A knowledge of the rate of a process can be used to predict the lifetime of that process. Thermogravimetric analysis (TGA) has frequently been used to determine kinetic information for degradation reactions in polymeric materials. Flynn and Wall studied a number of methods for using TGA experiments to determine kinetic information in polymer reactions. Kinetic parameters, such as the apparent activation energy and the frequency factor, can be determined in such experiments. Recently, researchers at the McDonnell Douglas Research Laboratory suggested that a graph of the logarithm of the frequency factor against the apparent activation energy can be used to predict long-term thermo-oxidative stability for polymeric materials. Such a graph has been called a kinetic map. In this study, thermogravimetric analyses were performed in air to study the thermo-oxidative degradation of several high performance polymers and to plot their kinetic parameters on a kinetic map.

Gas-driven permeation of deuterium through tungsten and tungsten alloys

Energy Technology Data Exchange (ETDEWEB)

Buchenauer, Dean A., E-mail: dabuche@sandia.gov [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States); Karnesky, Richard A. [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States); Fang, Zhigang Zak; Ren, Chai [University of Utah, Department of Metallurgical Engineering, Salt Lake City, UT 84112 (United States); Oya, Yasuhisa [Shizuoka University, Graduate School of Science, Shizuoka (Japan); Otsuka, Teppei [Kyushu University, Department of Advanced Energy Engineering Science, Fukuoka (Japan); Yamauchi, Yuji [Hokkaido University, Third Division of Quantum Science and Engineering, Faculty of Engineering, Sapporo (Japan); Whaley, Josh A. [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States)

2016-11-01

Highlights: • We have designed and performed initial studies on a high temperature gas-driven permeation cell capable of operating at temperatures up to 1150 °C and at pressures between 0.1–1 atm. • Permeation measurements on ITER grade tungsten compare well with past studies by Frauenfelder and Zahkarov in the temperature range from 500 to 1000 °C. • First permeation measurements on Ti dispersoid-strengthened ultra-fine grained tungsten show higher permeation at 500 °C, but very similar permeation with ITER tungsten at 1000 °C. Diffusion along grain boundaries may be playing a role for this type of material. - Abstract: To address the transport and trapping of hydrogen isotopes, several permeation experiments are being pursued at both Sandia National Laboratories (deuterium gas-driven permeation) and Idaho National Laboratories (tritium gas- and plasma-driven tritium permeation). These experiments are in part a collaboration between the US and Japan to study the performance of tungsten at divertor relevant temperatures (PHENIX). Here we report on the development of a high temperature (≤1150 °C) gas-driven permeation cell and initial measurements of deuterium permeation in several types of tungsten: high purity tungsten foil, ITER-grade tungsten (grains oriented through the membrane), and dispersoid-strengthened ultra-fine grain (UFG) tungsten being developed in the US. Experiments were performed at 500–1000 °C and 0.1–1.0 atm D{sub 2} pressure. Permeation through ITER-grade tungsten was similar to earlier W experiments by Frauenfelder (1968–69) and Zaharakov (1973). Data from the UFG alloy indicates marginally higher permeability (< 10×) at lower temperatures, but the permeability converges to that of the ITER tungsten at 1000 °C. The permeation cell uses only ceramic and graphite materials in the hot zone to reduce the possibility for oxidation of the sample membrane. Sealing pressure is applied externally, thereby allowing for elevation

Permeation of aromatic solvent mixtures through nitrile protective gloves.

Science.gov (United States)

Chao, Keh-Ping; Hsu, Ya-Ping; Chen, Su-Yi

2008-05-30

The permeation of binary and ternary mixtures of benzene, toluene, ethyl benzene and p-xylene through nitrile gloves were investigated using the ASTM F739 test cell. The more slowly permeating component of a mixture was accelerated to have a shorter breakthrough time than its pure form. The larger differences in solubility parameter between a solvent mixture and glove resulted in a lower permeation rate. Solubility parameter theory provides a potential approach to interpret the changes of permeation properties for BTEX mixtures through nitrile gloves. Using a one-dimensional diffusion model based on Fick's law, the permeation concentrations of ASTM F739 experiments were appropriately simulated by the estimated diffusion coefficient and solubility. This study will be a fundamental work for the risk assessment of the potential dermal exposure of workers wearing protective gloves.

Permeation of deuterium implanted into vanadium alloys

International Nuclear Information System (INIS)

Anderl, R.A.; Longhurst, G.R.; Struttmann, D.A.

1986-05-01

Permeation of deuterium through the vanadium alloy, V-15Cr-5Ti, was investigated using 3-keV, D 3 + ion beams from a small accelerator. The experiments consisted of measurements of the deuterium reemission and permeation rates as a function of implantation fluence for 0.5-mm thick specimens heated to tempertures from 623 to 823 0 K. Implantation-side surface characterization was made by simultaneous measurements of sputtered ions with a secondary ion mass spectrometer (SIMS). Analyses of these measurements indicate that for the experimental conditions used, the steady-state deuterium permeation flux in V-15Cr-5Ti is approximately 18% of the implantation flux. This corresponds to approximately 1000 times that seen in the ferritic steel, HT-9, under comparable conditions. Measurement of deuterium diffusivity in V-15Cr-5Ti using permeation break-through times indicates D = 1.4 x 10 -8 exp(-.11 eV/kT) (m 2 /s)

Separation of Aeruginosin-865 from Cultivated Soil Cyanobacterium (Nostoc sp.) by Centrifugal Partition Chromatography combined with Gel Permeation Chromatography

Czech Academy of Sciences Publication Activity Database

Cheel, José; Minceva, M.; Urajová, Petra; Aslam, R.; Hrouzek, Pavel; Kopecký, Jiří

2015-01-01

Roč. 10, č. 10 (2015), s. 1719-1722 ISSN 1934-578X R&D Projects: GA MŠk EE2.3.30.0059; GA MŠk ED2.1.00/03.0110; GA MŠk LO1416 Institutional support: RVO:61388971 Keywords : Cyanobacteria * Aeruginosin-865 * Centrifugal partition chromatography Subject RIV: EE - Microbiology, Virology Impact factor: 0.884, year: 2015

Hydrogen permeation properties of plasma-sprayed tungsten*1

Science.gov (United States)

Anderl, R. A.; Pawelko, R. J.; Hankins, M. R.; Longhurst, G. R.; Neiser, R. A.

1994-09-01

Tungsten has been proposed as a plasma-facing component material for advanced fusion facilities. This paper reports on laboratory-scale studies that were done to assess the hydrogen permeation properties of plasma-sprayed tungsten for such applications. The work entailed deuterium permeation measurements for plasma-sprayed (PS) tungsten coatings, sputter-deposited (SP) tungsten coatings, and steel substrate material using a mass-analyzed, 3 keV D 3+ ion beam with fluxes of ˜6.5 × 10 19 D/m 2 s. Extensive characterization analyses for the plasma-sprayed tungsten coatings were made using Auger spectrometry and scanning electron microscopy (SEM). Observed permeation rates through composite PS-tungsten/steel specimens were several orders of magnitude below the permeation levels observed for SP-tungsten/steel composite specimens and pure steel specimens. Characterization analyses indicated that the plasma-sprayed tungsten coating had a nonhomogeneous microstructure that consisted of splats with columnar solidification, partially-melted particles with grain boundaries, and void regions. Reduced permeation levels can be attributed to the complex microstructure and a substantial surface-connected porosity.

Thermogravimetric studies on the silicothermic reduction of uranium tetrafluoride under nitrogen

International Nuclear Information System (INIS)

Venkataramani, R.; Bhatt, Y.J.; Krishnamurthy, N.; Garg, S.P.

1986-01-01

This paper presents details of the experimental procedure and results obtained by thermogravimetric studies on the preparation of uranium nitrides by silicothermic reduction of uranium tetrafluoride under a nitrogen atmosphere. The folowing sequential steps are involved during the reaction: 4UF 4 +Si->4UF 3 +SiF 4 (g), 2UF 3 +Si+N 2 ->2UNF+SiF 4 (g), 4UNF+Si+N 2 ->2U 2 N 3 +SiF 4 (g), the uranium sesquintride U 2 N 3 obtained in the above process then decomposed at 1370 K under a dynamic vacuum of less than 10 -2 Tor to yield uranium mononitride of purity better than 99.9%, according to reaction 2U 2 N 3 ->4UN+N 2 (g). The chemical composition of the intermediate products formed during the sequential steps of the process, assessed by thermogravimetric and differential thermogravimetric studies, were further confirmed by chemical and X-ray analysis

Graft Copolymerization of Styrene from Poly(vinyl alcohol via RAFT Process

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Gholam Ali Koohmareh

2011-01-01

Full Text Available Polystyrene, PS, was grafted from poly(vinyl alcohol, PVA, backbone by reversible addition-fragmentation chain transfer (RAFT polymerization. The hydroxyl groups of the PVA were converted into aromatic dithioester RAFT agent and polymerization began in the presence of this agent. The structure of compounds was confirmed by FT-IR and 1HNMR spectroscopy. The graft copolymer was characterized by thermogravimetric analysis (TGA, X-ray diffraction (XRD, and scanning electron microscopy (SEM. Grafted polystyrene chains were cleaved from the PVA backbone by acidic hydrolysis of the PVA-g-PS, and its polydispersity index, PDI, was determined by gel permeation chromatography (GPC showing narrow molecular weight distribution.

Hydrogen permeation preventive structural materials

International Nuclear Information System (INIS)

Fukushima, Kimichika; Nakahigashi, Shigeo; Imura, Masashi; Terasawa, Michitaka; Ebisawa, Katsuyuki.

1986-01-01

Purpose: To provide highly practical wall materials for use in thermonuclear reactors capable of effectively preventing the permeation of hydrogen isotopes such as tritium thereby preventing the contamination of coolants. Constitution: Helium gas is injected into or at the surface of base materials comprising stainless steel plates to form a helium gas region. Alternatively, boron, nitrogen or the compound thereof having a greater helium forming nuclear reaction cross section than that of the base materials is mixed or injected into the base material to form the helium gas region through (n,α) reaction under neutron irradiation. Since the helium gas region constitutes a diffusion barrier for the tritium as the hydrogen isotope, the permeation amount of tritium is significantly suppressed. Helium gas bubbles or lattice defects are formed in the helium gas region under the neutron irradiation, by which the hydrogen isotope capturing effect can also be effected. In this way, permeation of the hydrogen isotope, contamination of the coolants, etc. can be prevented to provide great practical effectives. (Kawakami, Y.)

Reemission and permeation of deuterium implanted into metals

International Nuclear Information System (INIS)

Tanabe, T.; Furuyama, Y.; Imoto, S.

1984-01-01

Focusing on the marked depression of deuterium permeation rate during the deuteron bombardment, implantation experiments coupled with gaseous permeation experiments are performed on pure Ni and Ni with evaporated MnO. It is concluded that the reemission of implanted deuterium is initially depressed, but it soon becomes enhanced with increase of fluence leading to a rapid decrease of permeation rate at the intermediate temperatures 600-1000 K, which is attributed to the formation of short diffusion paths from the projected range to the front surface. (orig.)

Thermogravimetric investigations of cream with minoxidil

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I. V. Gnitko

2016-12-01

Full Text Available Minoxidil is one of the most effective and modern medications, which is used in modern trichology for hair growth stimulation in case of androgenic and other forms of alopecia. Clinical effect of this substance is caused by the intensification of metabolic processes in the skin due to intensification of microcirculation. For local application domestic dermatology uses imported minoxidil medicines in form of alcohol-water lotions and aerosols. The use of semisolid dosage form with minoxidil for external administration will allow to increase its efficacy and will widen the arsenal of domestic pharmacotherapeutic agents for hair growth stimulation. Rational composition of minoxidil semisolid dosage form for external use with 2% of active substance has been developed at the Department of Medicinal Preparations Technology, Zaporozhye State Medical University as a result of complex physical-chemical, microbiological and biopharmaceutical investigations. The aim of this work is the study of thermal treatment effects of cream-mask with minoxidil for external use over the temperature range, which is used in technological process of this dosage form manufacturing. Materials and methods. Cream with 2% of minoxidil on the emulsion base and its excipients have been used as the object for the thermogravimetric investigations. Thermogravimetric analysis has been carried out on the derivatograph «Shimadzu DTG-60», Japan, with the platinum and platinum-rhodium thermopair with samples’ heating in aluminium crucibles from 25 to 200ºС. Results. According to thermogravimetric experimental data minoxidil is a thermal stable substance from 26 to 240ºС. During experimental process insignificant endothermic effect was determined at 191,72ºС. However the mass of the example to the end of experiment practically didn’t change (decrease on 0,32%. Thermal effects on the derivatogram of minoxidil emulsion cream match with thermal effects of the base components and

THERMOGRAVIMETRIC INVESTIGATIONS OF VAGINAL SUPPOSITORY WITH THYME OIL

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N. V. Melnikova

2015-04-01

Full Text Available One of the main stages in new medicines creation is the development of their making technology. Technological process of suppository making includes ratherlongthermal treatment during preparation and homogenization of suppository base, active substancesaddition. These factors create danger of chemical and physical transformation of active substances and excipients in suppository up to their destruction and change of pharmacological and physical-chemical properties. Use of thermogravimetric analysis in pharmaceutical technology allows to studythepossibility of chemical interaction in dosage forms over the wide temperature range. The aim of this work is study of thermal treatmenteffects of suppository base with thyme oil over the temperature range of suppository manufacturing. Methods and results. As an object of thermogravimetric study vaginal suppository with thyme oil 0,2 g, suppository-placebo containing propylenglycol, polyethylene glycol 400, proxanol 268, twin 80 and the active ingredient of «Царствоароматов», Ukraine, production were used. Thermogravimetric analysis was carried out on the derivatograph«Shimadzu DTG-60», Japan, with the platinum and platinum-rhodiumthermopair with samples heating in aluminiumcrucibles from 25 to 200ºС. As standard α-Al2O3was used.Heating rate was 10ºСper min.Mass of the samples was 23,45– 39,63 mg. Obtained data were registered by the derivatograph as curves T, DTA, TGA. The T curve on the derivatogramm shows the temperature change and the TGA curve demonstrates the sample mass change during investigation. The DTA curve reflects differentiation of thermal effects and contains information about endothermic and exothermal maximum and is used for qualitative valuation of derivatogramm. According to results of thermogravimetric investigation the thyme oil is thermostable substance which is gradually evaporating during heating. So, at the beginning of study the test sample mass was 23

Development of a Contact Permeation Test Fixture and Method

Science.gov (United States)

2013-04-01

Permeation and Analytical Solutions Team Quality System documentation and the guidance found in the ISO 17025 standard. All permeation and...annular ring (left) and no pressure (right). 2.2.4 Quality Controls Analytical permeation testing was conducted in accordance with ISO 17025 quality...internal standard. This mixture was vortexed for 20–30 s then centrifuged at 15,000 rpm for 5 min in a Micromax microcentrifuge (Thermo IEC ; Needham

Measurement of Skin Permeation/Penetration of Nanoparticles for Their Safety Evaluation

OpenAIRE

木村, 恵理子; 河野, 雄一郎; 藤堂, 浩明; 五十嵐, 良明; 杉林, 堅次

2012-01-01

The aim of the present study was to quantitatively evaluate the skin permeation/penetration of nanomaterials and to consider their penetration pathway through skin. Firstly, penetration/permeation of a model fluorescent nanoparticle, Fluoresbrite?, was determined through intact rat skin and several damaged skins. Fluoresbrite? permeated through only needle-punctured skin. The permeation profiles of soluble high molecular compounds, fluorescein isothiocyanate-dextrans (FITC-dextrans, FDs), wit...

A simple HPLC method for the determination of halcinonide in lipid nanoparticles: development, validation, encapsulation efficiency, and in vitro drug permeation

Directory of Open Access Journals (Sweden)

Clarissa Elize Lopes

2017-06-01

Full Text Available ABSTRACT Halcinonide is a high-potency topical glucocorticoid used for skin inflammation treatments that presents toxic systemic effects. A simple and quick analytical method to quantify the amount of halcinonide encapsulated into lipid nanoparticles, such as polymeric lipid-core nanoparticles and solid lipid nanoparticles, was developed and validated regarding the drug's encapsulation efficiency and in vitro permeation. The development and validation of the analytical method were carried out using the high performance liquid chromatography with the UV detection at 239 nm. The validation parameters were specificity, linearity, precision and accuracy, limits of detection and quantitation, and robustness. The method presented an isocratic flow rate of 1.0 mL.min-1, a mobile phase methanol:water (85:15 v/v, and a retention time of 4.21 min. The method was validated according to international and national regulations. The halcinonide encapsulation efficiency in nanoparticles was greater than 99% and the in vitro drug permeation study showed that less than 9% of the drug permeated through the membrane, indicating a nanoparticle reservoir effect, which can reduce the halcinonide's toxic systemic effects. These studies demonstrated the applicability of the developed and validated analytical method to quantify halcinonide in lipid nanoparticles.

Effect of residual stresses on hydrogen permeation in iron

International Nuclear Information System (INIS)

Mouanga, M.; Bercot, P.; Takadoum, J.

2010-01-01

The effect of residual stresses on electrochemical permeation in iron membrane was investigated. Four thermal and mechanical treatments were chosen to obtain different surface states in relation to the residual stresses. Residual stresses were determined by X-ray diffraction (XRD) using the Macherauch and Mueller method. The results were completed by the microhardness measurements. For all iron membranes, compressive residual stresses were obtained. Electrochemical permeation experiments using a Devanathan and Stachurski cell were employed to determine the hydrogen permeation behaviour of the various iron membranes. The latter was charged with hydrogen by galvanostatic cathodic polarization in 0.1 M NaOH at 25 deg. C. The experimental results revealed that hydrogen permeation rate increases with increasing residual stresses introduced in iron membranes.

Design and tritium permeation analysis of China HCCB TBM port cell

International Nuclear Information System (INIS)

Jiangfeng, S.; Guoqiang, H.; Zhiyong, H.; Chang'an, C.; Deli, L.

2015-01-01

China is planning to develop a helium-cooled ceramic breeder (HCCB) test blanket module (TBM) on ITER to test key blanket technologies. In this paper, the design and tritium permeation analysis of China HCCB TBM port cell are introduced. A theoretical model has been developed to estimate tritium permeation rates and leak rates from the components and pipes which China has scheduled to house in the port cell. It is shown that on normal working conditions, the permeation and leak rate of the systems in the port cell will be no higher than 1.58 Ci/d without the use of tritium permeation barriers, and 0.10 Ci/d with the use of tritium permeation barriers. It also appears that tritium permeation barriers are necessary for high temperature components such as the reduction bed and the heater

Design and tritium permeation analysis of China HCCB TBM port cell

Energy Technology Data Exchange (ETDEWEB)

Jiangfeng, S.; Guoqiang, H.; Zhiyong, H.; Chang' an, C.; Deli, L. [China Academy of Engineering Physics, Mianyang, Sichuan (China)

2015-03-15

China is planning to develop a helium-cooled ceramic breeder (HCCB) test blanket module (TBM) on ITER to test key blanket technologies. In this paper, the design and tritium permeation analysis of China HCCB TBM port cell are introduced. A theoretical model has been developed to estimate tritium permeation rates and leak rates from the components and pipes which China has scheduled to house in the port cell. It is shown that on normal working conditions, the permeation and leak rate of the systems in the port cell will be no higher than 1.58 Ci/d without the use of tritium permeation barriers, and 0.10 Ci/d with the use of tritium permeation barriers. It also appears that tritium permeation barriers are necessary for high temperature components such as the reduction bed and the heater.

Permeation barrier properties of thin oxide films on flexible polymer substrates

International Nuclear Information System (INIS)

Fahlteich, John; Fahland, Matthias; Schoenberger, Waldemar; Schiller, Nicolas

2009-01-01

Solar cells and organic electronic devices require an encapsulation to ensure sufficient lifetime. Key parameters of the encapsulation are permeation barrier, UV stability, temperature stability, optical transmission spectra and mechanical stability. The requirements depend very much on the specific application. Many work groups suggest multilayer stacks to meet the permeation requirements. In this paper the permeation barrier properties of the different constituents of such a multilayer stack are characterized. Different layer materials are compared regarding their water vapour and oxygen permeability as well as the influence of process parameters is examined. Finally temperature dependent permeation measurements are used to characterize the permeation mechanisms in the different constituents of the multilayer barrier

Separation of aromatics by vapor permeation through solvent swollen membrane

Energy Technology Data Exchange (ETDEWEB)

Ito, A.; Adachi, K.; Feng, Y. [Niigata University, Niigata (Japan)

1995-12-20

A vapor permeation process for aromatics separation from a hydrocarbon mixture was studied by means of the simultaneous permeation of dimethylsulfoxide vapor as an agent for membrane swelling and preferential permeation of aromatics. The separation performance of the process was demonstrated by a polyvinylalcohol membrane for mixed vapors of benzene/cyclohexane, xylene/octane and a model gasoline. The aromatic vapors preferentially permeated from these mixed vapor feeds. The separation factor was over 10. The separation mechanism of the process mainly depends on the relative salability of the vapors between aromatics and other hydrocarbons in dimethylsulfoxide. 14 refs., 9 figs., 1 tab.

Permeation barrier for lightweight liquid hydrogen tanks

Energy Technology Data Exchange (ETDEWEB)

Schultheiss, D.

2007-04-16

For the future usage of hydrogen as an automotive fuel, its on-board storage is crucial. One approach is the storage of liquid hydrogen (LH2, 20 K) in double-walled, vacuum insulated tanks. The introduction of carbon fiber reinforced plastics (CFRP) as structural material enables a high potential of reducing the weight in comparison to the state-of-the-art stainless steel tanks. The generally high permeability of hydrogen through plastics, however, can lead to long-term degradation of the insulating vacuum. The derived objective of this dissertation was to find and apply an adequate permeation barrier (liner) on CFRP. The investigated liners were either foils adhered on CFRP specimens or coatings deposited on CFRP specimens. The coatings were produced by means of thermal spraying, metal plating or physical vapor deposition (PVD). The materials of the liners included Al, Au, Cu, Ni and Sn as well as stainless steel and diamond-like carbon. The produced liners were tested for their permeation behavior, thermal shock resistance and adherence to the CFRP substrate. Additionally, SEM micrographs were used to characterize and qualify the liners. The foils, although being a good permeation barrier, adhered weakly to the substrate. Furthermore, leak-free joining of foil segments is a challenge still to be solved. The metal plating liners exhibited the best properties. For instance, no permeation could be detected through a 50 {mu}m thick Cu coating within the accuracy of the measuring apparatus. This corresponds to a reduction of the permeation gas flow by more than factor 7400 compared to uncoated CFRP. In addition, the metal platings revealed a high adherence and thermal shock resistance. The coatings produced by means of thermal spraying and PVD did not show a sufficient permeation barrier effect. After having investigated the specimens, a 170 liter CFRP tank was fully coated with 50 {mu}m Cu by means of metal plating. (orig.)

Simplified tritium permeation model

International Nuclear Information System (INIS)

Longhurst, G.R.

1993-01-01

In this model I seek to provide a simplified approach to solving permeation problems addressed by TMAP4. I will assume that there are m one-dimensional segments with thickness L i , i = 1, 2, hor-ellipsis, m, joined in series with an implantation flux, J i , implanting at the single depth, δ, in the first segment. From material properties and heat transfer considerations, I calculate temperatures at each face of each segment, and from those temperatures I find local diffusivities and solubilities. I assume recombination coefficients K r1 and K r2 are known at the upstream and downstream faces, respectively, but the model will generate Baskes recombination coefficient values on demand. Here I first develop the steady-state concentration equations and then show how trapping considerations can lead to good estimates of permeation transient times

Method development and validation for the determination of pesticides in green coffee by gas chromatography

International Nuclear Information System (INIS)

Dallos Corredor, David; Guerrero Dallos, Jairo Arturo

2005-01-01

This study describes the implementation and validation of a multiresidue methodology for the determination of organochlorine, organophosphorus and pyrethroids pesticides in green coffee. Pesticides residues were extracted from green samples with an acetone-water (2:1) mixture followed by ethyl acetate cyclohexane (1:1) partitioning. The clean up steps include gel permeation chromatography and mini column chromatography using silica gel. Final determination was carried out by high-resolution gas chromatography with a pulsed split less injection mode and simultaneous detection by μ-ECD and NPD coupled in parallel. The methodology is specific, selective precise and accurate. Recoveries of majority of pesticides from spiked samples range from 70 to 110% at fortification levels of 0.038 mg/kg-1.536 mg/kg with limit of quantitation between 0.011 mg/kg and 0.100 mg/kg

Development of Novel Formulations to Enhance in Vivo Transdermal Permeation of Tocopherol

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Nada Aly H.

2014-09-01

Full Text Available Tocopherol represents a big challenge for transdermal permeation owing to its extreme hydrophobicity and large molecular mass. The aim of the present study was to develop alpha-tocopherol (T topical formulations and evaluate their ex vivo and in vivo permeation. Franz diffusion cells were used for ex vivo permeation, and neonatal rats were used for in vivo permeation. Seven gel formulations and 21 liquid formulations were investigated for physical stability, viscosity and permeation of T. Analysis of T was performed by a validated HPLC method using a UV detector. The ex vivo permeation from gel and emulsion formulations was very poor (0.001-0.015 %. Highest permeation was observed from monophasic liquid formulations containing dimethyl sulfoxide (DMSO, tocopheryl polyethylene glycols (TPGs, propylene glycol, ethanol and 9.5 % T. The in vivo results demonstrated higher retention in the epidermis compared to subcutaneous tissues, 1377 and 1.13 μg g-1, respectively. Increasing T concentration from 4.8 to 9.5 % did not increase the amount permeated or % of T retained. It was concluded that simple solutions of T in the presence of DMSO and TPGs were more promising systems for effective transdermal permeation compared to gel, emulsion or oleaginous systems.

Changes in molecular structure and properties of irradiated polymers of different compositions - ESR and NMR study

International Nuclear Information System (INIS)

Carswell-Pomerantz, T.; Babanalbandi, A.; Dong, L.; Hill, D.J.T.; Perera, M.C.S.; Pomery, P.J.; Saadat, G.; Whittaker, A.K.

1999-01-01

Investigations of molecular structural changes in polymers during exposure to high energy radiation is the long term interest of the Polymer Materials and Radiation Group at the University of Queensland. Recently, the group had looked at a range of polymers including natural and synthetic rubbers, methacrylates and polyesters. The objective of the work has been to investigate the relationships between polymer structure and sensitivity towards high energy radiation, including gamma radiation. This report will focus on the Electron Spin Resonance (ESR) and Nuclear Magnetic Resonance (NMR) studies of the effects of gamma irradiation on these polymers. Other methods such as Gas Chromatography (GC), Gel Permeation Chromatography (GPC), Fourier Transformed Infra Red (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Dynamic Mechanical Analysis (DMA) have also been used as these methods combine with ESR and NMR, to provide a more complete picture of the mechanism of the structural changes. (author)

Modeling benzene permeation through drinking water high density polyethylene (HDPE) pipes.

Science.gov (United States)

Mao, Feng; Ong, Say Kee; Gaunt, James A

2015-09-01

Organic compounds such as benzene, toluene, ethyl benzene and o-, m-, and p-xylene from contaminated soil and groundwater may permeate through thermoplastic pipes which are used for the conveyance of drinking water in water distribution systems. In this study, permeation parameters of benzene in 25 mm (1 inch) standard inside dimension ratio (SIDR) 9 high density polyethylene (HDPE) pipes were estimated by fitting the measured data to a permeation model based on a combination of equilibrium partitioning and Fick's diffusion. For bulk concentrations between 6.0 and 67.5 mg/L in soil pore water, the concentration-dependent diffusion coefficients of benzene were found to range from 2.0×10(-9) to 2.8×10(-9) cm2/s while the solubility coefficient was determined to be 23.7. The simulated permeation curves of benzene for SIDR 9 and SIDR 7 series of HDPE pipes indicated that small diameter pipes were more vulnerable to permeation of benzene than large diameter pipes, and the breakthrough of benzene into the HDPE pipe was retarded and the corresponding permeation flux decreased with an increase of the pipe thickness. HDPE pipes exposed to an instantaneous plume exhibited distinguishable permeation characteristics from those exposed to a continuous source with a constant input. The properties of aquifer such as dispersion coefficients (DL) also influenced the permeation behavior of benzene through HDPE pipes.

Thermogravimetric analysis and kinetic study of formation of lithium titanate by solid state route

International Nuclear Information System (INIS)

Sonak, Sagar; Jain, Uttam; Sahu, Ashok Kumar; Kumar, Sanjay; Krishnamurthy, Nagaiyar

2015-01-01

The kinetics of formation of lithium titanate from the solid state reaction of lithium carbonate and titanium oxide was studied using non-isothermal thermogravimetric technique. Thermogravimetric data for the reaction of lithium carbonate and titanium oxide was obtained at various heating rates. The methods such as Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose were used to estimate the kinetic parameters from the obtained thermogravimetric data. The average activation energy for the formation of lithium titanate by solid state route was found to be 243 kJ/mol K. The reaction mechanism was determined by the method given by Malek. It was found that the three dimensional diffusion model best describes the reaction kinetics. A kinetic equation describing the reaction is proposed and reaction mechanism is discussed

Synthesis of precursor the base of indene for polyelectrolyte an membrane production for application in fuel cell; Sintese de precursores a base de indeno para producao de polieletrolitos e membranas para uso em celula a combustivel

Energy Technology Data Exchange (ETDEWEB)

Brum, F.J.B.; Laux, F.N.; Haack, M.S.; Forte, M.M.C. [Universidade Federal do Rio Grande do Sul. Escola de Engenharia, Porto Alegre, RS (Brazil)

2010-07-01

Monomers with vinyl bond can be polymerized via a cationic mechanism using acid catalysts. This study aimed to obtain homo and copolymers of styrene and indene via cationic mechanism and the functionalization of sulfonic groups to the production of membranes for fuel cells. Polymers and poly electrolytes were characterized by infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and gel permeation chromatography (GPC/SEC). The degree of sulfonation of the polymers was determined by titration and evaluated for these films to the degree of swelling in water, ion exchange capacity and analysis of electrochemical impedance spectroscopy. Membranes prepared with polyindene and PVA were tested in an apparatus of the fuel cell. (author)

Synthesis and characterization of poly(ester amide from remewable resources through melt polycondensation

Directory of Open Access Journals (Sweden)

B. B. Wang

2014-01-01

Full Text Available Biodegradable poly(ester amides (PEAs were synthesized from lactic acid and 11-aminoundecanoic acid via melt polycondensation. Molecular weights, chemical structures and thermal properties of the poly(ester amides were characterized in terms of gel permeation chromatography (GPC, Fourier transform infrared spectroscopy (FTIR, 1H nuclear magnetic resonance (1H NMR, differential scanning calorimetry (DSC and thermogravimetric analysis (TGA, respectively. The PEAs have low molecular weights and display a lower cold crystallization temperature as well as smaller crystallinity by comparison with the pure poly(lactic acid (PLA. The incorporation of the 11-aminoundecanoic acid into the PLA chain not only improved the thermal stability but changed the decomposition process.

Deuterium permeation and diffusion in high-purity beryllium

International Nuclear Information System (INIS)

Abramov, E.; Riehm, M.P.; Thompson, D.A.; Smeltzer, W.W.

1990-01-01

The permeation rate of deuterium through high-purity beryllium membranes was measured using the gas-driven permeation technique. The time-dependent and the steady-state deuterium flux data were analyzed and the effective diffusivities of the samples were determined. Using multilayer permeation theory the effects of surface oxide were eliminated and the diffusion coefficients of the bulk beryllium determined. The diffusion parameters obtained for the extra-grade beryllium samples (99.8%) are D 0 =6.7x10 -9 m 2 /s and E D =28.4 kJ/mol. For the high-grade beryllium samples (99%) the parameters are D 0 =8.0x10 -9 m 2 /s and E D =35.1 kJ/mol. (orig.)

Recent results on implantation and permeation into fusion reactor materials

Science.gov (United States)

Anderl, R. A.; Holland, D. F.; Longhurst, G. R.; Struttman, D. A.

This paper reports on implantation-driven permeation experiments that have been made for primary candidate alloy (PCA) and the ferritic steel HT-9 using deuterium ion beams from an accelerator. The results include measurements of the implantation flux and fluence dependence of the deuterium reemission and permeation for specimens heated to approximately 430(0)C. Simultaneous measurements of the ions sputtered from the specimen front surface with a secondary ion mass spectrometer provided some characterization of the surface condition throughout an experiment. For both materials, the permeation rate was lowered by the implantation process. However, the steady state permeation rate for HT-9 was found to be at least a factor of 5 greater than that for PCA.

Towards a unified model of passive drug permeation I: origins of the unstirred water layer with applications to ionic permeation.

Science.gov (United States)

Ghosh, Avijit; Scott, Dennis O; Maurer, Tristan S

2014-02-14

In this work, we provide a unified theoretical framework describing how drug molecules can permeate across membranes in neutral and ionized forms for unstirred in vitro systems. The analysis provides a self-consistent basis for the origin of the unstirred water layer (UWL) within the Nernst-Planck framework in the fully unstirred limit and further provides an accounting mechanism based simply on the bulk aqueous solvent diffusion constant of the drug molecule. Our framework makes no new assumptions about the underlying physics of molecular permeation. We hold simply that Nernst-Planck is a reasonable approximation at low concentrations and all physical systems must conserve mass. The applicability of the derived framework has been examined both with respect to the effect of stirring and externally applied voltages to measured permeability. The analysis contains data for 9 compounds extracted from the literature representing a range of permeabilities and aqueous diffusion coefficients. Applicability with respect to ionized permeation is examined using literature data for the permanently charged cation, crystal violet, providing a basis for the underlying mechanism for ionized drug permeation for this molecule as being due to mobile counter-current flow. Copyright © 2013 Elsevier B.V. All rights reserved.

Electrochemical measurement of tritium and hydrogen permeation through iron membranes

International Nuclear Information System (INIS)

Hagi, Hideki; Hayashi, Yasunori

1987-01-01

Permeation rates of tritium and hydrogen through iron were measured by the electro-chemical method in which an aqueous solution containing 3.7 x 10 12 Bq/m 3 tritium was used as a cathodic electrolyte. Tritium and hydrogen were introduced from one side of a specimen by cathodic polarization with a constant current density, while at the other side of the specimen the permeated tritium and hydrogen were extracted by potentiostatical ionization. Nearly all of the potentiostatic current on the extraction side is produced by the ionization of hydrogen, because the concentration of tritium in the cathodic electrolyte is very small. The amount of permeated hydrogen was obtained by integrating the potentiostatic current, and that of permeated tritium was determined by measuring the radioactivity of the electrolyte sampled from the anodic side. The separation factor for permeation obtained under steady state conditions (the ratio of permeation rates of hydrogen to tritium divided by the ratio of the concentration of hydrogen to tritium in the cathodic electrolyte) is 12 at 288 K. This value is independent of cathodic current density. Diffusion coefficients of tritium (D T ) and hydrogen (D H ) in iron were determined from the tritium and hydrogen permeation by using time lag technique. For annealed iron at 286 K, D T = 9 x 10 -10 m 2 /s and D H = 4 x 10 -9 m 2 /s, and for 9 % cold-worked iron at 284 K, D T = 3 x 10 -10 m 2 /s and D H = 4 x 10 -10 m 2 /s. (author)

Compensation effect in H 2 permeation kinetics of PdAg membranes

KAUST Repository

Zeng, Gaofeng

2012-08-30

Knowledge about the (inter)dependence of permeation kinetic parameters on the stoichiometry of H 2-selective alloys is still rudimentary, although uncovering the underlying systematic correlations will greatly facilitate current efforts into the design of novel high-performance H 2 separation membranes. Permeation measurements with carefully engineered, 2-7 μm thick supported Pd 100-xAg x membranes reveal that the activation energy and pre-exponential factor of H 2 permeation laws vary systematically with alloy composition, and both kinetic parameters are strongly correlated for x ≤ 50. We show that this permeation kinetic compensation effect corresponds well with similar correlations in the hydrogen solution thermodynamics and diffusion kinetics of PdAg alloys that govern H 2 permeation rates. This effect enables the consistent description of permeation characteristics over wide temperature and alloy stoichiometry ranges, whereas hydrogen solution thermodynamics may play a role, too, as a yet unrecognized source of kinetic compensation in, for example, H 2-involving reactions over metal catalysts or hydrogenation/ dehydrogenation of hydrogen storage materials. © 2012 American Chemical Society.

Thermogravimetric Analysis of Single-Wall Carbon Nanotubes

Science.gov (United States)

Arepalli, Sivram; Nikolaev, Pavel; Gorelik, Olga

2010-01-01

An improved protocol for thermogravimetric analysis (TGA) of samples of single-wall carbon nanotube (SWCNT) material has been developed to increase the degree of consistency among results so that meaningful comparisons can be made among different samples. This improved TGA protocol is suitable for incorporation into the protocol for characterization of carbon nanotube material. In most cases, TGA of carbon nanotube materials is performed in gas mixtures that contain oxygen at various concentrations. The improved protocol is summarized.

[Study on essential oil separation from Forsythia suspensa oil-bearing water body based on vapor permeation membrane separation technology].

Science.gov (United States)

Zhang, Qian; Zhu, Hua-Xu; Tang, Zhi-Shu; Pan, Yong-Lan; Li, Bo; Fu, Ting-Ming; Yao, Wei-Wei; Liu, Hong-Bo; Pan, Lin-Mei

2018-04-01

To investigate the feasibility of vapor permeation membrane technology in separating essential oil from oil-water extract by taking the Forsythia suspensa as an example. The polydimethylsiloxane/polyvinylidene fluoride (PDMS/PVDF) composite flat membrane and a polyvinylidene fluoride (PVDF) flat membrane was collected as the membrane material respectively. Two kinds of membrane osmotic liquids were collected by self-made vapor permeation device. The yield of essential oil separated and enriched from two kinds of membrane materials was calculated, and the microscopic changes of membrane materials were analyzed and compared. Meanwhile, gas chromatography-mass spectrometry (GC-MS) was used to compare and analyze the differences in chemical compositions of essential oil between traditional steam distillation, PVDF membrane enriched method and PDMS/PVDF membrane enriched method. The results showed that the yield of essential oil enriched by PVDF membrane was significantly higher than that of PDMS/PVDF membrane, and the GC-MS spectrum showed that the content of main compositions was higher than that of PDMS/PVDF membrane; The GC-MS spectra showed that the components of essential oil enriched by PVDF membrane were basically the same as those obtained by traditional steam distillation. The above results showed that vapor permeation membrane separation technology shall be feasible for the separation of Forsythia essential oil-bearing water body, and PVDF membrane was more suitable for separation and enrichment of Forsythia essential oil than PDMS/PVDF membrane. Copyright© by the Chinese Pharmaceutical Association.

A versatile, stability-indicating and high-throughput ultra-fast liquid chromatography method for the determination of isoflavone aglycones in soybeans, topical formulations, and permeation assays.

Science.gov (United States)

Nemitz, Marina C; Yatsu, Francini K J; Bidone, Juliana; Koester, Letícia S; Bassani, Valquiria L; Garcia, Cássia V; Mendez, Andreas S L; von Poser, Gilsane L; Teixeira, Helder F

2015-03-01

There is a growing interest in the pharmaceutical field concerning isoflavones topical delivery systems, especially with regard to their skin care properties and antiherpetic activity. In this context, the present work describes an ultra-fast liquid chromatography method (UFLC) for determining daidzein, glycitein, and genistein in different matrices during the development of topical systems containing isoflavone aglycones (IA) obtained from soybeans. The method showed to be specific, precise, accurate, and linear (0.1 to 5 µg mL(-1)) for IA determination in soybean acid extract, IA-rich fraction obtained after the purification process, IA loaded-nanoemulsions, and topical hydrogel, as well as for permeation/retention assays in porcine skin and porcine esophageal mucosa. The matrix effect was determined for all complex matrices, demonstrating low effect during the analysis. The stability indicating UFLC method was verified by submitting IA to acidic, alkaline, oxidative, and thermal stress conditions, and no interference of degradation products was detected during analysis. Mass spectrometry was performed to show the main compounds produced after acid hydrolysis of soybeans, as well as suggest the main degradation products formed after stress conditions. Besides the IA, hydroxymethylfurfural and ethoxymethylfurfural were produced and identified after acid hydrolysis of the soybean extract and well separated by the UFLC method. The method's robustness was confirmed using the Plackett-Burman experimental design. Therefore, the new method affords fast IA analysis during routine processes, extract purification, products development, and bioanalytical assays. Copyright © 2014 Elsevier B.V. All rights reserved.

Temperature dependence of the resonance frequency of thermogravimetric devices

NARCIS (Netherlands)

Iervolino, E.; Riccio, M.; Van Herwaarden, A.W.; Irace, A.; Breglio, G.; Van der Vlist, W.; Sarro, P.M.

2010-01-01

This paper investigates the temperature dependence of the resonance frequency of thermogravimetric (TG) devices for tip heating over the temperature range of View the MathML source 25–600?C. The resonance frequency of a fabricated TG device shows to be temperature independent for tip heating up to

Hydrogen gas driven permeation through tungsten deposition layer formed by hydrogen plasma sputtering

International Nuclear Information System (INIS)

Uehara, Keiichiro; Katayama, Kazunari; Date, Hiroyuki; Fukada, Satoshi

2015-01-01

Highlights: • H permeation tests for W layer formed by H plasma sputtering are performed. • H permeation flux through W layer is larger than that through W bulk. • H diffusivity in W layer is smaller than that in W bulk. • The equilibrium H concentration in W layer is larger than that in W bulk. - Abstract: It is important to evaluate the influence of deposition layers formed on plasma facing wall on tritium permeation and tritium retention in the vessel of a fusion reactor from a viewpoint of safety. In this work, tungsten deposition layers having different thickness and porosity were formed on circular nickel plates by hydrogen RF plasma sputtering. Hydrogen permeation experiment was carried out at the temperature range from 250 °C to 500 °C and at hydrogen pressure range from 1013 Pa to 101,300 Pa. The hydrogen permeation flux through the nickel plate with tungsten deposition layer was significantly smaller than that through a bare nickel plate. This indicates that a rate-controlling step in hydrogen permeation was not permeation through the nickel plate but permeation though the deposition layer. The pressure dependence on the permeation flux differed by temperature. Hydrogen permeation flux through tungsten deposition layer is larger than that through tungsten bulk. From analysis of the permeation curves, it was indicated that hydrogen diffusivity in tungsten deposition layer is smaller than that in tungsten bulk and the equilibrium hydrogen concentration in tungsten deposition layer is enormously larger than that in tungsten bulk at same hydrogen pressure.

Deuterium permeation and diffusion in high purity beryllium

International Nuclear Information System (INIS)

Abramov, E.

1990-05-01

The permeation rate of deuterium through high-purity beryllium membranes was measured using the gas-driven permeation technique. The time-dependent and the steady-state deuterium flux data were analyzed and the effective diffusivities of the samples were determined. A multilayer permeation theory was used in order to eliminate the surface oxide effects and the diffusion coefficients of the bulk beryllium were determined. The diffusion parameters obtained for the extra-grade beryllium samples (99.8%) are D 0 = 6.7 x 10 -9 [m 2 /s] and E D = 28.4 [KJ/mol]; and for the high-grade beryllium samples (99%) the parameters are D 0 = 8.0 x 10 -9 [m 2 /s] and E D = 35.1 [KJ/mol

Hydrogen ion-driven permeation in carbonaceous films

International Nuclear Information System (INIS)

Anderl, R.A.; Holland, D.F.; Longhurst, G.R.

1989-01-01

This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C:H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D 3 + ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5x10 14 D/cm 2 s to 5x10 15 D/cm 2 s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C:H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C:H films. (orig.)

Hydrogen ion-driven permeation in carbonaceous films

Energy Technology Data Exchange (ETDEWEB)

Anderl, R.A.; Holland, D.F.; Longhurst, G.R.

1989-04-01

This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C:H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D/sub 3//sup +/ ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5x10/sup 14/ D/cm/sup 2/ s to 5x10/sup 15/ D/cm/sup 2/ s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C:H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C:H films. (orig.).

Hydrogen ion-driven permeation in carbonaceous films

Science.gov (United States)

Anderl, R. A.; Holland, D. F.; Longhurst, G. R.

1989-04-01

This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C: H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D +3 ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5 × 10 14D/ cm2 s to 5 × 10 15D/ cm2 s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C : H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C : H films.

Thermogravimetric studies of vapour-aerosol interactions

International Nuclear Information System (INIS)

Henshaw, J.; Newland, M.S.; Wood, S.J.

1991-01-01

Thermogravimetric analysis has been used to study the interaction of iodine vapour with cadmium, silver and manganese monoxide substrates. These studies have demonstrated the importance of time-dependence data on reaction rates. Iodine did not react with manganese monoxide (as expected from thermodynamic considerations); however, extensive reaction did occur with silver and cadmium. Two rate limiting mechanisms were observed: mass transfer of iodine molecules from the gas phase (leading to linear reaction rates) and parabolic kinetics (ie inversely proportional to the extent of reaction) when the rate was limited by a diffusion process through the reaction product. (author)

Purity Evaluation of Single-Walled Carbon Nanotubes Using Thermogravimetric Analysis

International Nuclear Information System (INIS)

Goak, Jeung Choon; Kim, Tae Yang; Jung, Jongwan; Seo, Young-Soo; Lee, Naesung; Sok, Junghyun

2013-01-01

This study evaluated the purity of single-walled carbon nanotubes (SWCNTs) in the arc-synthesized SWCNT samples by using thermogravimetric analysis (TGA). The as-produced SWCNT samples were heat-treated in air for 20 h at 275-475°C and characterized by scanning and transmission electron microscopes and TGA to establish oxidation temperature ranges of SWCNTs and carbonaceous impurities comprising the samples. Based on these oxidation temperature ranges, derivative thermogravimetric curves were deconvoluted, and differentiated peaks were assigned to SWCNTs and carbonaceous impurities. The compositions and the SWCNT purities of the samples were obtained simply by calculating the areal ratios under the deconvoluted curves. TGA studies on purity evaluation and thermal stabilities of SWCNTs and carbonaceous impurities are likely to provide us with a simple route of thermal oxidation purification to acquire high-purity SWCNT samples.

Gas chromatography-mass spectrometry analysis of di-n-octyl disulfide in a straight oil metalworking fluid: application of differential permeation and Box-Cox transformation.

Science.gov (United States)

Xu, Wenhai; Que Hee, Shane S

2006-01-06

The aim of this study was to identify and quantify an unknown peak in the chromatogram of a very complex mixture, a straight oil metalworking fluid (MWF). The fraction that permeated through a thin nitrile polymer membrane had less mineral oil background than the original MWF did at the retention time of the unknown peak, thus facilitating identification by total ion current (TIC) gas chromatography-mass spectrometry (GC-MS). The peak proved to be di-n-octyl disulfide (DOD) through retention time and mass spectral comparisons. Quantitation of DOD was by extracted ion chromatogram analysis of the DOD molecular ion (mass-to-charge ratio (m/z) 290), and of the m/z 71 ion for the internal standard, n-triacontane. Linear models of the area ratio (y) of these two ions versus DOD concentration showed a systematic negative bias at low concentrations, a common occurrence in analysis. The linear model of y(0.8) (from Box-Cox power transformation) versus DOD concentration showed negligible bias from the lowest measured standard of 1.51 mg/L to the highest concentration tested at 75.5 mg/L. The intercept did not differ statistically from zero. The concentration of DOD in the MWF was then calculated to be 0.398+/-0.034% (w/w) by the internal standard method, and 0.387+/-0.036% (w/w) by the method of standard additions. These two results were not significantly different at p Box-Cox transformation is therefore recommended when the data for standards are non-linear.

Separating esterase targets of organophosphorus compounds in the brain by preparative chromatography.

Science.gov (United States)

Mangas, I; Vilanova, E; Benabent, M; Estévez, J

2014-02-10

Low level exposure to organophosphorus esters (OPs) may cause long-term neurological effects and affect specific cognition domains in experimental animals and humans. Action on known targets cannot explain most of these effects by. Soluble carboxylesterases (EC 3.1.1.1) of chicken brain have been kinetically discriminated using paraoxon, mipafox and phenylmethyl sulfonylfluoride as inhibitors and phenyl valerate as a substrate. Three different enzymatic components were discriminated and called Eα, Eβ and Eγ. In this work, a fractionation procedure with various steps was developed using protein native separation methods by preparative HPLC. Gel permeation chromatography followed by ion exchange chromatography allowed enriched fractions with different kinetic behaviors. The soluble chicken brain fraction was fractionated, while total esterase activity, proteins and enzymatic components Eα, Eβ and Eγ were monitored in each subfraction. After the analysis, 13 fractions were pooled and conserved. Preincubation of the soluble chicken brain fraction of with the organophosphorus mipafox gave rise to a major change in the ion exchange chromatography profile, but not in the molecular exchanged chromatography profile, which suggest that mipafox permanently modifies the ionic properties of numerous proteins. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Penetration of radionuclides across the skin. Rat age dependent promethium permeation through skin in vitro

International Nuclear Information System (INIS)

Kassai, Z.; Kassai, A.; Bauerova, K.; Koprda, V.; Harangozo, M.; Bendova, P.; Bujnova, A.

2003-01-01

The composition and the permeation properties of the skin are dependent on age. In the animal models for permation studies, age affects the mechanical as well as the permeation properties significantly. The time dependence of permeation of 147 Pm 3+ from aqueous solution was established by the animal skin model and the age dependence of promethium permeation through the skin was examined. The aim was to find the optimum rat skin age model for radionuclide permeation studies and to assess the relative importance of the main permeation pathways: transepidermal and transfollicular permeation. The skin from 5-day-old rats (5DR) was found to represent the optimum animal model to study transepidermal permeation of ions. The skin from 9-day-old rats (9DR) was selected to study transfollicular permeation of ions. Comparison of the permeated amounts of promethium through the skin without hairs (3 DR to 6 DR) and with hairs (7DR to 12DR) showed that the additional permation mode via follicles significantly contributed to the permeation rate and extent. (author)

Current Design of the Flange Type Hydrogen Permeation Sensor in Liquid Breeder

International Nuclear Information System (INIS)

Lee, E. H.; Jin, H. G.; Yoon, J. S.; Kim, S. K.; Lee, D. W.; Lee, H. G.

2015-01-01

In 2004, A. Ciampichetti et al. proposed a hollow capsule shape permeation sensor and they theoretically and experimentally evaluated the performance of the sensor made of Nb membrane at test condition of 500 .deg. C. However, the evaluation result showed the measured hydrogen permeation flux in the sensor much lower than the predicted one and they concluded that, the result is due to the formation of an oxide layer on the sensor membrane surface. Three years later, A. Ciampichetti et al. observed that a hollow capsule shape permeation sensor has too long response time to measure hydrogen concentration in liquid breeder. However, they suggested optimizing the sensor geometry with the reduction of the ratio 'total sensor volume/permeation surface' to overcome the low hydrogen permeating flux. For development of the liquid breeding technologies in nuclear fusion, the permeation sensor to measure tritium concentration in liquid metal breeder has been developed. Lee et al. proposed a flange type permeation sensor to dramatically reduce the ratio sensor 'inside volume/permeation surface' and to remove membrane welding during sensor manufacture process. However, the flange type sensor has problem with sealing. In present study, the modified flange sensor design with a metallic C-ring spring gasket is introduced. The modified sensor will be verified and evaluated under high temperature conditions by end of 2015

Current Design of the Flange Type Hydrogen Permeation Sensor in Liquid Breeder

Energy Technology Data Exchange (ETDEWEB)

Lee, E. H.; Jin, H. G.; Yoon, J. S.; Kim, S. K.; Lee, D. W. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, H. G. [National Fusion Research Institute, Daejeon (Korea, Republic of)

2015-10-15

In 2004, A. Ciampichetti et al. proposed a hollow capsule shape permeation sensor and they theoretically and experimentally evaluated the performance of the sensor made of Nb membrane at test condition of 500 .deg. C. However, the evaluation result showed the measured hydrogen permeation flux in the sensor much lower than the predicted one and they concluded that, the result is due to the formation of an oxide layer on the sensor membrane surface. Three years later, A. Ciampichetti et al. observed that a hollow capsule shape permeation sensor has too long response time to measure hydrogen concentration in liquid breeder. However, they suggested optimizing the sensor geometry with the reduction of the ratio 'total sensor volume/permeation surface' to overcome the low hydrogen permeating flux. For development of the liquid breeding technologies in nuclear fusion, the permeation sensor to measure tritium concentration in liquid metal breeder has been developed. Lee et al. proposed a flange type permeation sensor to dramatically reduce the ratio sensor 'inside volume/permeation surface' and to remove membrane welding during sensor manufacture process. However, the flange type sensor has problem with sealing. In present study, the modified flange sensor design with a metallic C-ring spring gasket is introduced. The modified sensor will be verified and evaluated under high temperature conditions by end of 2015.

Computer calculations of activation energy for pyrolysis from thermogravimetric curves

International Nuclear Information System (INIS)

Hussain, R.

1994-01-01

A BASIC programme to determine energy of activation for the degradation of polymers has been described. The calculations are based on the results of thermogravimetric curves. This method is applicable for those polymers which produce volatile products upon thermal degradation. (author)

Comparison on implantation-driven permeation characteristics of fusion reactor structural materials

Energy Technology Data Exchange (ETDEWEB)

Longhurst, G.R.; Anderl, R.A.; Struttmann, D.A. (Idaho National Engineering Lab., Idaho Falls)

Implantation-driven permeation experiments have been conducted on samples of the ferritic steel HT-9, the austenitic Primary Candidate Alloy (PCA) and the vanadium alloy V-15Cr-5Ti using D{sub 3}{sup +} ions under conditions that simulate charge-exchange neutral loading on a fusion reactor first wall. The steels all exhibited an initially intense permeation spike followed by an exponential decrease to low steady-state values. That spike was not evident in the V-15Cr-5Ti experiments. Steady-state permeation was highest in the vanadium alloy and lowest in the austenitic steel. Though permeation rates in the HT-9 were lower than those in V-15Cr-5Ti, permeation transients were much faster in HT-9 than in other materials tested. Sputtering of the steel surface resulted in enhanced reemission, whereas in the vanadium tests, recombination and diffusivity both appeared to diminish as the deuterium concentration rose. We conclude that for conditions comparable to those of these experiments, tritium retention and permeation loss in first wall structures made of steels will be less than in structures made of V-15Cr-5Ti.

The formation of tritium permeation barriers by CVD

International Nuclear Information System (INIS)

Forcey, K.S.; Perujo, A.; Reiter, F.; Lolli-Ceroni, P.L.

1993-01-01

The effectiveness as permeation barriers of the following CVD coatings have been investigated: TiC (1 to 2 μm in thickness); a bi-layer of TiN on TiC (3 μm total thickness) and CVD Al 2 O 3 on a TiN/TiC bi-layer. The substrate materials were TZM (a Mo alloy) and 316L stainless steel in the form of discs of diameter 48 mm and thickness 0.1 or 1 mm. Permeation measurements were performed in the temperature range 515-742 K using deuterium at pressures in the range 1-50 kPa. CVD layers were shown to form reasonably effective permeation barriers. At a temperature of 673 K TiC is around 6000 times less permeable to deuterium than 316L stainless steel. (orig.)

Ion-driven deuterium permeation through tungsten at high temperatures

Science.gov (United States)

Gasparyan, Yu. M.; Golubeva, A. V.; Mayer, M.; Pisarev, A. A.; Roth, J.

2009-06-01

The ion-driven permeation (IDP) through 50 μm thick pure tungsten foils was measured in the temperature range of 823-923 K during irradiation by 200 eV/D + ion beam with a flux of 10 17-10 18 D/m 2s. Gas driven permeation (GDP) from the deuterium background gas was observed as well. Calculations using both the analytical formula for the diffusion limited regime (DLR) and the TMAP 7 code gave good agreement with the experimental data. Defects with a detrapping energy of (2.05 ± 0.15) eV were found to limit the permeation lag time in our experimental conditions.

Ion-driven deuterium permeation through tungsten at high temperatures

Energy Technology Data Exchange (ETDEWEB)

Gasparyan, Yu.M., E-mail: yury.gasparyan@ipp.mpg.d [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmanstrasse 2, D-85748 Garching (Germany); Moscow Engineering and Physics Institute, Kashirskoe sh. 31, Moscow 115409 (Russian Federation); Golubeva, A.V. [RRC ' Kurchatov Institute' , Ac. Kurchatov sq., 1/1, Moscow RU-123182 (Russian Federation); Mayer, M. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmanstrasse 2, D-85748 Garching (Germany); Pisarev, A.A. [Moscow Engineering and Physics Institute, Kashirskoe sh. 31, Moscow 115409 (Russian Federation); Roth, J. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmanstrasse 2, D-85748 Garching (Germany)

2009-06-15

The ion-driven permeation (IDP) through 50 mum thick pure tungsten foils was measured in the temperature range of 823-923 K during irradiation by 200 eV/D{sup +} ion beam with a flux of 10{sup 17}-10{sup 18} D/m{sup 2}s. Gas driven permeation (GDP) from the deuterium background gas was observed as well. Calculations using both the analytical formula for the diffusion limited regime (DLR) and the TMAP 7 code gave good agreement with the experimental data. Defects with a detrapping energy of (2.05 +- 0.15) eV were found to limit the permeation lag time in our experimental conditions.

Ion-driven deuterium permeation through tungsten at high temperatures

International Nuclear Information System (INIS)

Gasparyan, Yu.M.; Golubeva, A.V.; Mayer, M.; Pisarev, A.A.; Roth, J.

2009-01-01

The ion-driven permeation (IDP) through 50 μm thick pure tungsten foils was measured in the temperature range of 823-923 K during irradiation by 200 eV/D + ion beam with a flux of 10 17 -10 18 D/m 2 s. Gas driven permeation (GDP) from the deuterium background gas was observed as well. Calculations using both the analytical formula for the diffusion limited regime (DLR) and the TMAP 7 code gave good agreement with the experimental data. Defects with a detrapping energy of (2.05 ± 0.15) eV were found to limit the permeation lag time in our experimental conditions.

Volatile Organic Compound (VOC Removal by Vapor Permeation at Low VOC Concentrations: Laboratory Scale Results and Modeling for Scale Up

Directory of Open Access Journals (Sweden)

Philippe Moulin

2011-03-01

Full Text Available Petroleum transformation industries have applied membrane processes for solvent and hydrocarbon recovery as an economic alternative to reduce their emissions and reuse evaporated components. Separation of the volatile organic compounds (VOCs (toluene-propylene-butadiene from air was performed using a poly dimethyl siloxane (PDMS/α-alumina membrane. The experimental set-up followed the constant pressure/variable flow set-up and was operated at ~21 °C. The membrane is held in a stainless steel module and has a separation area of 55 × 10−4 m². Feed stream was set to atmospheric pressure and permeate side to vacuum between 3 and 5 mbar. To determine the performance of the module, the removed fraction of VOC was analyzed by Gas Chromatography/Flame Ionization Detector (GC/FID. The separation of the binary, ternary and quaternary hydrocarbon mixtures from air was performed at different flow rates and more especially at low concentrations. The permeate flux, permeance, enrichment factor, separation efficiency and the recovery extent of the membrane were determined as a function of these operating conditions. The permeability coefficients and the permeate flux through the composite PDMS-alumina membrane follow the order given by the Hildebrand parameter: toluene > 1,3-butadiene > propylene. The simulated data for the binary VOC/air mixtures showed fairly good agreement with the experimental results in the case of 1,3-butadiene and propylene. The discrepancies observed for toluene permeation could be minimized by taking into account the effects of the porous support and an influence of the concentration polarization. Finally, the installation of a 0.02 m2 membrane module would reduce 95% of the VOC content introduced at real concentration conditions used in the oil industry.

Heater-Integrated Cantilevers for Nano-Samples Thermogravimetric Analysis

OpenAIRE

Toffoli, Valeria; Carrato, Sergio; Lee, Dongkyu; Jeon, Sangmin; Lazzarino, Marco

2013-01-01

The design and characteristics of a micro-system for thermogravimetric analysis (TGA) in which heater, temperature sensor and mass sensor are integrated into a single device are presented. The system consists of a suspended cantilever that incorporates a microfabricated resistor, used as both heater and thermometer. A three-dimensional finite element analysis was used to define the structure parameters. TGA sensors were fabricated by standard microlithographic techniques and tested using mill...

Thermogravimetric evaluation of the suitability of precursors for MOCVD

International Nuclear Information System (INIS)

Kunte, G V; Shivashankar, S A; Umarji, A M

2008-01-01

A method based on the Langmuir equation for the estimation of vapour pressure and enthalpy of sublimation of subliming compounds is described. The variable temperature thermogravimetric/differential thermogravimetric (TG/DTG) curve of benzoic acid is used to arrive at the instrument parameters. Employing these parameters, the vapour pressure–temperature curves are derived for salicylic acid and camphor from their TG/DTG curves. The values match well with vapour pressure data in the literature, obtained by effusion methods. By employing the Clausius–Clapeyron equation, the enthalpy of sublimation could be calculated. Extending the method further, two precursors for metal-organic chemical vapour deposition (MOCVD) of titanium oxide bis-isopropyl bis tert-butyl 2-oxobutanoato titanium, Ti(O i Pr) 2 (tbob) 2 , and bis-oxo-bis-tertbutyl 2-oxobutanoato titanium, [TiO(tbob) 2 ] 2 , have been evaluated. The complex Ti(O i Pr) 2 (tbob) 2 is found to be a more suitable precursor. This approach can be helpful in quickly screening for the suitability of a compound as a CVD precursor

Purification Simulation With Vapor Permeation and Distillation-Adsorption In Bioethanol Plant

Directory of Open Access Journals (Sweden)

Misri Gozan

2017-04-01

Full Text Available High purity of Bioethanol is required in biofuel mixing with gasoline (EXX. In bioethanol production line, the azeotropic property of ethanol-water becomes the barrier for purification process. This study examined two bioethanol separation processes by support of simulation tools, Superpro Designer 9.0 software. Ethanol purity and a low costeconomical process were the major considerations. Purification method of vapor permeation membrane technology was compared with distillation-adsorption method. Data from previous lab experiments and some literatures were used. The results showed that distillation-adsorption method is more economical compared to vapor permeation technology. Payback period of the simulation is 3.9 years and 4.3 years to distillation adsorption and vapor permeation respectively with each IRR value is 20.23% and 17.89%. Initial investment value of vapor permeation is 9.6% higher than distillation method. Significant difference observed in operating costs, since more units involved in vapor permeation require more labors to operate.

Recent developments in skin mimic systems to predict transdermal permeation.

Science.gov (United States)

Waters, Laura J

2015-01-01

In recent years there has been a drive to create experimental techniques that can facilitate the accurate and precise prediction of transdermal permeation without the use of in vivo studies. This review considers why permeation data is essential, provides a brief summary as to how skin acts as a natural barrier to permeation and discusses why in vivo studies are undesirable. This is followed by an in-depth discussion on the extensive range of alternative methods that have been developed in recent years. All of the major 'skin mimic systems' are considered including: in vitro models using synthetic membranes, mathematical models including quantitative structure-permeability relationships (QSPRs), human skin equivalents and chromatographic based methods. All of these model based systems are ideally trying to achieve the same end-point, namely a reliable in vitro-in vivo correlation, i.e. matching non-in vivo obtained data with that from human clinical trials. It is only by achieving this aim, that any new method of obtaining permeation data can be acknowledged as a potential replacement for animal studies, for the determination of transdermal permeation. In this review, the relevance and potential applicability of the various models systems will also be discussed.

SAMPA: A free software tool for skin and membrane permeation data analysis.

Science.gov (United States)

Bezrouk, Aleš; Fiala, Zdeněk; Kotingová, Lenka; Krulichová, Iva Selke; Kopečná, Monika; Vávrová, Kateřina

2017-10-01

Skin and membrane permeation experiments comprise an important step in the development of a transdermal or topical formulation or toxicological risk assessment. The standard method for analyzing these data relies on the linear part of a permeation profile. However, it is difficult to objectively determine when the profile becomes linear, or the experiment duration may be insufficient to reach a maximum or steady state. Here, we present a software tool for Skin And Membrane Permeation data Analysis, SAMPA, that is easy to use and overcomes several of these difficulties. The SAMPA method and software have been validated on in vitro and in vivo permeation data on human, pig and rat skin and model stratum corneum lipid membranes using compounds that range from highly lipophilic polycyclic aromatic hydrocarbons to highly hydrophilic antiviral drug, with and without two permeation enhancers. The SAMPA performance was compared with the standard method using a linear part of the permeation profile and a complex mathematical model. SAMPA is a user-friendly, open-source software tool for analyzing the data obtained from skin and membrane permeation experiments. It runs on a Microsoft Windows platform and is freely available as a Supporting file to this article. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tritium inventory and permeation in the ITER breeding blanket

International Nuclear Information System (INIS)

Violante, V.; Tosti, S.; Sibilia, C.; Felli, F.; Casadio, S.; Alvani, C.

2000-01-01

A model has allowed us to perform the analysis of the tritium inventory and permeation in the international thermonuclear experimental reactor (ITER) breeding blanket under the hypothesis of steady state conditions. Li 2 ZrO 3 (reference) and Li 2 TiO 3 (alternative) have been studied as breeding materials. The total breeder inventory assessed is 7.64 g for the Li 2 ZrO 3 at reference temperature. The model has also been used for a parametric analysis of the tritium permeation. At reference temperature and purge helium velocity of 0.01 m/s, the HT partial pressure is ranging from 10 to 30 Pa in the breeder and 1.5x10 -3 Pa in the beryllium. At 0.1 m/s of purge helium velocity, the HT partial pressure is reduced of one order by magnitude in the breeder and becomes 5x10 -5 Pa in the beryllium. The tritium permeation into the coolant for the whole blanket is ranging from 100 to 250 mCi per day for purge helium velocity of 0.01 m/s. The analysis of the tritium inventory and permeation for the alternative Li 2 TiO 3 breeding material has been carried out too. The tritium inventory in the breeder is in the range from 6 to 375 g larger than in Li 2 ZrO 3 by about a factor 5; the tritium permeation into coolant is comparable to the Li 2 ZrO 3 one. This analysis provides indications on the influence of the operating parameters on the tritium control in the ITER breeding blanket; particularly the control of the tritium inventory by the temperature and the tritium permeation by the purge gas velocity

Changes on iron electrode surface during hydrogen permeation in borate buffer solution

International Nuclear Information System (INIS)

Modiano, S.; Carreno, J.A.V.; Fugivara, C.S.; Torresi, R.M.; Vivier, V.; Benedetti, A.V.; Mattos, O.R.

2008-01-01

Hydrogen interaction with oxide films grown on iron electrodes at open circuit potential (E oc ) and in the passive region (+0.30 V ECS ) was studied by chronopotentiometry, chronoamperometry and electrochemical impedance spectroscopy techniques. The results were obtained in deaerated 0.3 mol L -1 H 3 BO 3 + 0.075 mol L -1 Na 2 B 4 O 7 (BB, pH 8.4) solution before, during and after hydrogen permeation. The iron oxide film modification was also investigated by means of in situ X-ray absorption near-edge spectroscopy (XANES) and scanning electrochemical microscopy (SECM) before and during hydrogen permeation. The main conclusion was that the passive film is reduced during the hydrogen diffusion. The hydrogen permeation stabilizes the iron surface at a potential close to the thermodynamic water stability line where hydrogen evolution can occur. The stationary condition required for the determination of the permeation parameters cannot be easily attained on iron surface during hydrogen permeation. Moreover, additional attention must be paid when obtaining the transport parameters using the classical permeation cell

Thermogravimetric study of γ-irradiated lanthanum oxalate

International Nuclear Information System (INIS)

Nayak, H.; Bhatta, D.

2000-01-01

Thermogravimetric study of La 2 (C 2 O 4 ) 3 , exposed to different doses (5.0 - 50.0 x 10 -2 MGy) of γ-rays has been carried out. Marginal effect is observed at lower doses which is prominent at higher dose (5.0 x 10 -1 MGy). The radiolytic damaged entities, generated by irradiation favours the reaction by creating new potential nucleation centres in the lattice. The solid product, La 2 O 3 formed by irradiation also acts as a heterogeneous catalyst and brings out changes in the reactivity of the solid. (author)

Miniature quartz crystal-resonator-based thermogravimetric detector.

Science.gov (United States)

Sai, N; Tagawa, Y; Sohgawa, M; Abe, T

2014-09-01

In this work, a new design for a microheater combined with a quartz crystal microbalance (QCM) array for thermogravimetric analysis is presented. Each QCM consists of two electrodes to excite thickness-shear-mode vibrations and one microheater to increase the temperature on the crystal backside. In addition, all the electrode pads are patterned on the crystal backside, making the design of the QCM compact and user-friendly. Finally, the proposed QCM array was employed to separate ethanol from methanol. This was successfully achieved via thermal desorption spectra calculated by differentiating the frequency changes.

Thermogravimetric control of intermediate compounds in uranium metallurgy

International Nuclear Information System (INIS)

Gasco Sanchez, L.; Fernandez Cellini, R.

1959-01-01

The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs

Investigation of fatigue and mechanical properties of the pipe grade poly(vinyl chloride using recycled scraps

Directory of Open Access Journals (Sweden)

J-M. Lee

2015-04-01

Full Text Available In this paper, the effect of using pre-consumer PVC scraps on static and long-term mechanical properties is studied. The degradation characteristics of mixing virgin PVC with crushed pre-consumer and PVC pipe scraps are analyzed using various tools including Gel Permeation Chromatography (GPC, Thermogravimetric Analysis (TGA, X-ray fluorescence (XRF and Fourier Transform Infrared (FTIR spectroscopy. The variation of static mechanical properties as a function of adding pre-consumer PVC pipe scraps is investigated using the degradation analyses of recycled PVC scraps. In addition, fatigue tests are executed to evaluate the long-term durability of blending virgin PVC and recycled PVC scraps, and the fracture surface is investigated in detail to reveal the variation of the fracture mechanisms.

Synthesis, characterization and thermal degradation of cross-linked polystyrene using the alkyne-functionalized esters as a cross-linker agent by click chemistry method

Directory of Open Access Journals (Sweden)

Hakan Akat

2015-08-01

Full Text Available AbstractIn this study, it has been demonstrated that cross-linked polystyrene (CPS was successfully prepared by using click chemistry. For this purpose, firstly, poly (styrene-co-4 chloromethylstyrene with 4-chloromethylstyrene was synthesized. Secondly, alkyne-functionalized esters (dipropargyl adipate, dipropargyl succinate were obtained using propargyl alcohol, adipoyl chloride and succinyl chloride. Azide-functionalized polystrene (PS-N3 and dipropargyl adipate (or dipropargyl succinate were reacted in N,N-dimethylformamide for 24 h at room temperature to give CPS. The synthesized polymer and compounds were characterized by nuclear magnetic resonance (1H-NMR, gel permeation chromatography (GPC, fourier transform infrared spectroscopy (FT-IR and thermogravimetric (TG/DTG analysis.. The surface properties were investigated by Scanning Electron Micrography (SEM.

Synthesis and Characterization of Konjac Glucomannan-Graft-Polyacrylamide via γ-Irradiation

Directory of Open Access Journals (Sweden)

Jie Pang

2008-03-01

Full Text Available The synthesis of konjac glucomannan-graft-polyacrylamide (KGM-g-PAM wascarried out at 25°C by γ-irradiation under a N2 atmosphere. The effects of absorbedradiation dosage and monomer concentration on grafting yield and water absorbency werestudied. The grafted copolymers were characterized using Fourier Transform Infrared(FTIR spectroscopy, nuclear magnetic resonance (NMR, x-ray diffraction (XRD,thermogravimetric analysis (TGA and gel permeation chromatography (GPC. Thegrafting yield was observed to increase with increasing absorbed dosage and monomerconcentration. Compared with the original KGM, the grafted copolymers exhibited betterthermal stability and water absorbency. The results suggest that γ-irradiation is convenientand efficient for inducing graft copolymerization of KGM and acrylamide (AM.

Thermogravimetric analysis in the characterization of colombian coals used in the production of coke

International Nuclear Information System (INIS)

Guerrero, Camilo; Salamanca, Monica E; Diaz, Jose de J

2010-01-01

Five types of coal from the states of Cundinamarca, Boyaca and Norte de Santander (Colombia) were characterized by proximate, ultimate, rheological, petrographic, calorific and thermogravimetric analysis. The parameters used, especially the ones which determine the rheological properties show that the studied coals and its blends could produce good quality coke. It was observed the inverse relationship between the volatile matter content and the mean vitrinite reflectance, relationship which is attributed to the increase of the aromaticity in the molecular structure of the coal as a consequence of the rank increase. The parameters derived from the thermogravimetric analysis, maximum velocity of de-volatilization and the temperature of maximum velocity of de-volatilization and the media reflectance of the vitrinite showed good correlations. Also was observed an interesting correlation between the velocity of de-volatilization and maximum fluidity. This shows that the thermogravimetric analysis can be a useful tool to characterize in a quick way coals used for metallurgical coke production.

Electrochemical measurement of tritium and hydrogen permeation through iron membranes

International Nuclear Information System (INIS)

Hagi, Hideki; Hayashi, Yasunori

1988-01-01

Permeation rates of tritium and hydrogen through iron were measured by the electrochemical method in which an aqueous solution containing 3.7 x 10 12 Bq/m 3 tritium was used as a cathodic electrolyte. Tritium and hydrogen were introduced from one side of a specimen by cathodic polarization with a constant current density, while at the other side of the specimen the permeated tritium and hydrogen were extracted by potentiostatical ionization. Nearly all of the potentiostatic current of the extraction side stands for the ionization of hydrogen, because the concentration of tritium in the cathodic electrolyte is very small. The amount of permeated hydrogen was obtained by integrating the anodic current, and that of tritium was determined by measuring the radioactivity of the electrolyte sampled from the extraction side. The separation factor for permeation obtained under steady state conditions (the ratio of permeation rates of hydrogen to tritium divided by the ratio of the concentration of hydrogen to tritium in the charging electrolyte) is 12 at 288 K. This value is independent of cathodic current density. Diffusion coefficients of tritium (D T ) and hydrogen (D H ) in iron were determined from the time lag of tritium and hydrogen permeation. For annealed specimens at 286 K, D T = 9 x 10 -10 m 2 /s and D H = 4 x 10 -9 m 2 /s, and for 9% cold-worked specimens at 284 K, D T = 3 x 10 -10 m 2 /s and D H = 4 x 10 -10 m 2 /s. (author)

Re-evaluation of SiC permeation coefficients at high temperatures

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Yasushi, E-mail: yama3707@kansai-u.ac.jp [Faculty of Engineering Science, Kansai Univ., Yamate-cho, Suita, Osaka 564-8680 (Japan); Murakami, Yuichiro; Yamaguchi, Hirosato; Yamamoto, Takehiro; Yonetsu, Daigo [Faculty of Engineering Science, Kansai Univ., Yamate-cho, Suita, Osaka 564-8680 (Japan); Noborio, Kazuyuki [Hydrogen Isotope Research Center, Univ. of Toyama, Toyama, Toyama 930-8555 (Japan); Konishi, Satoshi [Institute of Advanced Energy, Kyoto Univ., Gokasho, Uji, Kyoto 611-0011 (Japan)

2016-11-01

Highlights: • The deuterium permeation coefficients of CVD-SiC at 600–950 °C were evaluated. • The wraparound flow was reduced to less than 1/100th of the permeation flow. • CVD-SiC materials are very effective as hydrogen isotope permeation barriers. - Abstract: Since 2007, our group has studied the deuterium permeation and diffusion coefficients for SiC materials at temperatures above 600 °C as a means of evaluating the tritium inventory and permeation in fusion blankets. During such measurements, control and evaluation of the wraparound flow through the sample holder are important, and so the heated sample holder is enclosed by a glass tube and kept under vacuum during experimental trials. However, detailed studies regarding the required degree of vacuum based on model calculations have shown that the wraparound flow is much larger than expected, and so can affect measurements at high temperatures. We therefore modified the measurement apparatus based on calculations involving reduced pressure in the glass tube, and are now confident that the measurement error is only several percent, even at 950 °C. In this paper, recent experimental results obtained with a chemical vapor deposition (CVD)-SiC sample over the temperature range of 600–950 °C are presented, showing that the permeation coefficient for CVD-SiC is more than three orders of magnitude smaller than that for stainless steel (SS316) at 600 °C, and that at 950 °C, the coefficient for CVD-SiC is almost equal to that for SUS316 at 550 °C.

Thermogravimetric analysis of the polymer acrylate-vinyl ether mixture cured by radiation

International Nuclear Information System (INIS)

Danu, Sugiarto

1998-01-01

An experiment on thermal stability of the polymer acrylate-vinyl ether mixture cured by radiation have been done using thermogravimetric analysis. Three kinds of acrylic oligomers i.e., epoxy acrylate, urethane acrylate, and polypropylene glycol diacrylate, and vinyl ether monomers i.e., triethylene glycol divinyl ether (DVE-3), 1,4-cyclohexane dimethanol divinyl ether (CHVE), and butanediol monovinyl ether (HBVE) were used in the experiment. Reaction was taken via radical and cationic polymerisation. In case of cationic polymerisation, diphenyliodonium hexafluorophosphate fotoinisiator was used in the formulation. Thermogravimetric analysis was conducted in a nitrogen atmosphere at a flow rate of 40 ml/minute with a constant heating rate 10 o C and evaluation range were done from 25 to 500 o C. The results of thermogravimetric analysis showed that acrylate and DVE-3 mixture produced the polymer films with higher thermal stability than the mixture of acrylate with CHVE or HBVE. The composition of acrylate-vinyl ether mixture and degree of unsaturation of vinyl ether monomers influenced the thermal stability of polymer. The mixture of epoxy acrylate-vinyl ether and polypropylene glycol diacrylate-vinyl ether have 1 initial decomposition temperature whereas the urethane acrylate-vinyl ether mixture has 2 initial decomposition temperatures. (authors)

Uses and evaluation methods of potential hydrogen permeation barriers for nuclear reactor materials

International Nuclear Information System (INIS)

Noga, J.O.; Piercy, G.R.; Bowker, J.T.

1985-07-01

This report summarizes results on the use of coatings as hydrogen permeation barriers on nuclear reactor component materials. Two classes of base materials were considered, exothermic hydrogen absorbers and endothermic hydrogen absorbers. The results of the tests indicate that substantial reductions in the amount of hydrogen absorbed by a metal can be achieved through the use of hydrogen permeation barrier coatings. Gold was determined to provide an effective hydrogen permeation barrier on Zr-2-1/2 Nb pressure tube material. Tin was determined to be a suitable hydrogen permeation barrier when applied on AISI 410 stainless steel and iron. Both gas phase and electrochemical permeation techniques were used to determine hydrogen permeabilities through coatings and base materials

Drug Release and Skin Permeation from Lipid Liquid Crystalline Phases

Science.gov (United States)

Costa-Balogh, F. O.; Sparr, E.; Sousa, J. J. S.; Pais, A. A. C. C.

We have studied drug release and skin permeation from several different liquid crystalline lipid formulations that may be used to control the respective release rates. We have studied the release and permeation through human skin of a water-soluble and amphiphilic drug, propranolol hydrochloride, from several formulations prepared with monoolein and phytantriol as permeation enhancers and controlled release excipients. Diolein and cineol were added to selected formulations. We observed that viscosity decreases with drug load, wich is compatible with the occurrence of phase changes. Diolein stabilizes the bicontinuous cubic phases leading to an increase in viscosity and sustained release of the drug. The slowest release was found for the cubic phases with higher viscosity. Studies on skin permeation showed that these latter formulations also presented lower permeability than the less viscous monoolein lamellar phases. Formulations containing cineol originated higher permeability with higher enhancement ratios. Thus, the various formulations are adapted to different circumstances and delivery routes. While a slow release is usually desired for drug sustained delivery, the transdermal route may require a faster release. Lamellar phases, which are less viscous, are more adapted to transdermal applications. Thus, systems involving lamellar phases of monoolein and cineol are good candidates to be used as skin permeation enhancers for propranolol hydrochloride.

Implications of recent implantation-driven permeation experiments for fusion reactor safety

International Nuclear Information System (INIS)

Longhurst, G.R.; Anderl, R.A.; Struttmann, D.A.

1986-01-01

Metal structures exposed to the plasma in tritium-burning fusion reactors will be subject to implantation-driven permeation (IDP) of tritium. Permeation rates for IDP in fusion structural materials are usually high because the tritium atoms enter the material without having to go through the dissociation and solution steps required of tritium-bearing gas molecules. These surface processes, which may be rate limiting in PDP, actually enhance permeation in IDP by inhibiting the return of tritium to the plasma side of the structure. Experiments have been conducted at the Idaho National Engineering Laboratory (INEL) to investigate the nature of IDP by simulating conditions experienced by structures exposed to the plasma. These experiments have shown that surface conditions are important to tritium permeation in materials endothermic to hydrogen solution such as austenitic and ferritic steels. In reactive metals such as vanadium, surface processes appear to totally control the permeation. The purpose of this paper is to review the progress of those experiments and to discuss the implications that the results have regarding the tritium-related safety concerns of fusion reactors

Thermogravimetric analysis of reactor-neutrons-irradiated LEXAN polycarbonate film

International Nuclear Information System (INIS)

Kalsi, P.C.

2000-01-01

The effects of reactor-neutrons irradiation on the thermogravimetric (TG) analysis of LEXAN polycarbonate film in air were studied. Irradiation enhances the degradation rate and the effect increases further with increasing neutron fluence. The kinetics of the different steps of degradation were also evaluated from the TG curves. The activation energy values calculated for all the degradation stages decrease on irradiation. (author)

Thermogravimetric and differential thermal analysis of potassium bicarbonate contaminated cellulose

Science.gov (United States)

A. Broido

1966-01-01

When samples undergo a complicated set of simultaneous and sequential reactions, as cellulose does on heating, results of thermogravimetric and differential thermal analyses are difficult to interpret. Nevertheless, careful comparison of pure and contaminated samples, pyrolyzed under identical conditions, can yield useful information. In these experiments TGA and DTA...

SC lipid model membranes designed for studying impact of ceramide species on drug diffusion and permeation--part II: diffusion and permeation of model drugs.

Science.gov (United States)

Ochalek, M; Podhaisky, H; Ruettinger, H-H; Wohlrab, J; Neubert, R H H

2012-10-01

The barrier function of two quaternary stratum corneum (SC) lipid model membranes, which were previously characterized with regard to the lipid organization, was investigated based on diffusion studies of model drugs with varying lipophilicities. Diffusion experiments of a hydrophilic drug, urea, and more lipophilic drugs than urea (i.e. caffeine, diclofenac sodium) were conducted using Franz-type diffusion cells. The amount of permeated drug was analyzed using either HPLC or CE technique. The subjects of interest in the present study were the investigation of the influence of physicochemical properties of model drugs on their diffusion and permeation through SC lipid model membranes, as well as the study of the impact of the constituents of these artificial systems (particularly ceramide species) on their barrier properties. The diffusion through both SC lipid model membranes and the human SC of the most hydrophilic model drug, urea, was faster than the permeation of the more lipophilic drugs. The slowest rate of permeation through SC lipid systems occurred in the case of caffeine. The composition of SC lipid model membranes has a significant impact on their barrier function. Model drugs diffused and permeated faster through Membrane II (presence of Cer [EOS]). In terms of the barrier properties, Membrane II is much more similar to the human SC than Membrane I. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of permeation enhancers on the penetration mechanism of transfersomal gel of ketoconazole

Directory of Open Access Journals (Sweden)

Reshmy Rajan

2012-01-01

Full Text Available The aim of the present research work was to investigate the potential of transfersome formulations for transdermal delivery of Ketoconazole (KTZ. KTZ is a broad-spectrum antifungal agent that is active against a wide variety of fungi and yeasts. It is readily but incompletely absorbed after oral dosing and is highly variable. The transfersomes were formulated by lipid film hydration technique using Rotary vacuum Evaporator. The prepared transfersomes were converted into suitable gel formulation and is evaluated for their gel characteristics like pH, viscosity, spreadability, extrudability, homogeneity, drug content, etc. Suitable essential oils acting as natural permeation enhancers were added to the transfersomal formulation of KTZ for their release studies. Studies proved that addition of suitable permeation enhancers to the transfersomal formulation improved the release and permeation of KTZ, which showed that the permeation enhancers modify the barrier to penetration present in skin without itself undergoing any change. From the various essential oils which are used as permeation enhancers, the formulation containing Eucalyptus oil showed better in vitro release and permeation as compared with other formulations containing different permeation enhancers.

Practical experience of backwashing with SWRO permeate for UF fouling control

KAUST Repository

Li, Sheng; Heijman, Sebastiaan G J; Verberk, J. Q J C; Amy, Gary L.; Van Dijk, Johannis C.

2013-01-01

Effectiveness of seawater reverse osmosis (SWRO) permeate backwash on fouling control of seawater ultrafiltration was investigated at a pilot scale. A standard membrane module was used in this pilot to represent full-scale desalination plants. Results of the pilot show a good reproducibility. When the UF permeate was used for backwash, the frequency of chemically enhanced backwash (CEB) was around once per day. However, results of the pilot show that SWRO permeate backwashing could significantly reduce the CEB frequency. © 2013 Desalination Publications.

A comparison of implantation-driven permeation characteristics of fusion reactor structural materials

Science.gov (United States)

Longhurst, G. R.; Anderl, R. A.; Struttmann, D. A.

1986-11-01

Implantation-driven permeation experiments have been conducted on samples of the ferritic steel HT-9, the austenitic Primary Candidate Alloy (PCA) and the vanadium alloy V-15Cr-5Ti using D 3+ ions under conditions that simulate charge-exchange neutral loading on a fusion reactor first wall. The steels all exhibited an initially intense permeation "spike" followed by an exponential decrease to low steady-state values. That spike was not evident in the V-15Cr-5Ti experiments. Steady-state permeation was highest in the vanadium alloy and lowest in the austenitic steel. Though permeation rates in the HT-9 were lower than those in V-15Cr-5Ti, permeation transients were much faster in HT-9 than in other materials tested. Sputtering of the steel surface resulted in enhanced reemission, whereas in the vanadium tests, recombination and diffusivity both appeared to diminish as the deuterium concentration rose. We conclude that for conditions comparable to those of these experiments, tritium retention and permeation loss in first wall structures made of steels will be less than in structures made of V-15Cr-5Ti.

Hydrogen permeation inhibition by zinc-nickel alloy plating on steel XC68

International Nuclear Information System (INIS)

El Hajjami, A.; Gigandet, M.P.; De Petris-Wery, M.; Catonne, J.C.; Duprat, J.J.; Thiery, L.; Raulin, F.; Starck, B.; Remy, P.

2008-01-01

The inhibition of hydrogen permeation and barrier effect by zinc-nickel plating was investigated using the Devanathan-Stachurski permeation technique. The hydrogen permeation and hydrogen diffusion for the zinc-nickel (12-15%) plating on steel XC68 is compared with zinc and nickel. Hydrogen permeation and hydrogen diffusion were followed as functions of time at current density applied (cathodic side) and potential permanent (anodic side). The hydrogen permeation inhibition for zinc-nickel is intermediate to that of nickel and zinc. This inhibition was due to nickel-rich layer effects at the Zn-Ni alloy/substrate interface, is shown by GDOES. Zinc-nickel plating inhibited the hydrogen diffusion greater as compared to zinc. This diffusion resistance was due to the barrier effect caused by the nickel which is present at the interface and transformed the hydrogen atomic to Ni 2 H compound, as shown by GIXRD.

Hydrogen permeation inhibition by zinc-nickel alloy plating on steel XC68

Energy Technology Data Exchange (ETDEWEB)

El Hajjami, A. [Institut UTINAM, UMR CNRS 6213, Sonochimie et Reactivite des Surfaces, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France); Coventya S.A.S., 51 rue Pierre, 92588 Clichy Cedex (France); Gigandet, M.P. [Institut UTINAM, UMR CNRS 6213, Sonochimie et Reactivite des Surfaces, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France)], E-mail: marie-pierre.gigandet@univ-fcomte.fr; De Petris-Wery, M. [Institut Universitaire de Technologie d' Orsay, Universite Paris XI, Plateau de Moulon, 91400 Orsay (France); Catonne, J.C. [Professeur Honoraire du Conservatoire national des arts et metiers (CNAM), Paris (France); Duprat, J.J.; Thiery, L.; Raulin, F. [Coventya S.A.S., 51 rue Pierre, 92588 Clichy Cedex (France); Starck, B.; Remy, P. [Lisi Automotive, 28 faubourg de Belfort, BP 19, 90101 Delle Cedex (France)

2008-12-30

The inhibition of hydrogen permeation and barrier effect by zinc-nickel plating was investigated using the Devanathan-Stachurski permeation technique. The hydrogen permeation and hydrogen diffusion for the zinc-nickel (12-15%) plating on steel XC68 is compared with zinc and nickel. Hydrogen permeation and hydrogen diffusion were followed as functions of time at current density applied (cathodic side) and potential permanent (anodic side). The hydrogen permeation inhibition for zinc-nickel is intermediate to that of nickel and zinc. This inhibition was due to nickel-rich layer effects at the Zn-Ni alloy/substrate interface, is shown by GDOES. Zinc-nickel plating inhibited the hydrogen diffusion greater as compared to zinc. This diffusion resistance was due to the barrier effect caused by the nickel which is present at the interface and transformed the hydrogen atomic to Ni{sub 2}H compound, as shown by GIXRD.

Permeated defect detecting test method and device in reactor

International Nuclear Information System (INIS)

Sakurai, Yoshishige.

1996-01-01

The present invention provides a method of and a device capable of performing a test for entire inner surfaces of the reactor upon periodical inspection of a BWR type reactor while sufficiently taking countermeasures for radiation rays into consideration. Namely, the present invention comprises following steps. (1) A provisional step for taking a shroud head of a reactor core shroud and incore structural components above and below the shroud out of the reactor, discharging reactor water and water tightly closing openings such as reactor wall perforation holes, (2) a pretreatment step for washing exposed inner surfaces of the reactor and peeling deteriorated materials, (3) a first drying step for drying portions washed and peeled in the step (2), (4) a permeation step for applying a permeation liquid of a defect detecting medium on the exposed inner surfaces of the reactor, (5) a permeation liquid removing step for removing the an excess permeation liquid in the step (4), (6) a second drying step for drying corresponding portions after performing the step (5), and (7) a flaw detecting step for optically observing the corresponding portions after performing the step (6) and detecting flaws. (I.S.)

A study on reverse osmosis permeating treatment for yarn dyeing ...

African Journals Online (AJOL)

This paper presents a fuzzy linear regression model for estimation of reverse osmosis permeating parameters conditions. The proposed model can effectively take on non-crisp, fuzzy and crisp data. This study model used for estimation of reverse osmosis permeating parameters data from Tirupur examines the variables that ...

Effect of Nutrient Formulations on Permeation of Proteins and Lipids ...

African Journals Online (AJOL)

Purpose: To investigate the effect of nutrient formulations on the permeation of proteins and lipids through porcine intestine in vitro. Method: In vitro permeation studies of proteins and lipids of two peptide-based formulations, composed of various compounds and sources of hydrolyzed protein was carried out, and compared ...

Studies on Tasar Cocoon Cooking Using Permeation Method

Science.gov (United States)

Javali, Uday C.; Malali, Kiran B.; Ramya, H. G.; Naik, Subhas V.; Padaki, Naveen V.

2018-02-01

Cocoon cooking is an important process before reeling of tasar silk yarn. Cooking ensures loosening of the filaments in the tasar cocoons thereby easing the process of yarn withdrawal during reeling process. Tasar cocoons have very hard shell and hence these cocoons need chemical cooking process to loosen the silk filaments. Attempt has been made in this article to study the effect of using vacuum permeation chamber for tasar cocoon cooking in order to reduce the cooking time and improve the quality of tasar silk yarn. Vacuum assisted permeation cooking method has been studied in this article on tasar daba cocoons for cooking efficiency, deflossing and reelability. Its efficiency has been evaluated with respect to different cooking methods viz, traditional and open pan cooking methods. The tasar silk produced after reeling process has been tested for fineness, strength and cohesion properties. Results indicate that permeation method of tasar cooking ensures uniform cooking with higher efficiency along with better reeling performance and improved yarn properties.

Development of tritium permeation barriers on Al base in Europe

Science.gov (United States)

Benamati, G.; Chabrol, C.; Perujo, A.; Rigal, E.; Glasbrenner, H.

The development of the water cooled lithium lead (WCLL) DEMO fusion reactor requires the production of a material capable of acting as a tritium permeation barrier (TPB). In the DEMO blanket reactor permeation barriers on the structural material are required to reduce the tritium permeation from the Pb-17Li or the plasma into the cooling water to acceptable levels (HIP) technology and spray (this one developed also for repair) deposition techniques. The final goal is to select a reference technique to be used in the blanket of the DEMO reactor and in the ITER test module fabrication. The activities performed in four European laboratories are summarised here.

Tritium permeation in stainless-steel structures exposed to plasma ions

International Nuclear Information System (INIS)

Anderl, R.A.; Holland, D.F.; Struttmann, D.A.; Longhurst, G.R.; Merrill, B.J.

1985-01-01

This paper presents a comparison of the hydrogen permeation properties of the austenitic primary candidate alloy, PCA, and of the advanced ferritic alloy, HT-9. The comparison is based on experimental measurements of the permeation and reemission of deuterium from specimens undergoing implantation with 3-keV, D 3 + ions produced by an accelerator. Characterization of the specimen surface facing the ion beam is provided by secondary ion mass spectrometer (SIMS) analysis of the species sputtered from the surface during the implantation. Recombination and diffusivity data for PCA and HT-9 were derived from an analysis in which model calculations were applied to the reemission and permeation measurements

Tritium permeation and recovery for the Flibe/He blanket design

International Nuclear Information System (INIS)

Moir, R.

1984-10-01

This study assumes tritium to be a gas dissolved in molten salt, with TF formation suppressed. Tritium permeates readily through the hot steel tubes of the reactor and steam generator and will leak into the steam system at the rate of about one gram per day in the absence of special permeation barriers, assuming that 1% of the helium coolant flow rate is processed for tritium recovery at 90% efficiency per pass. Tritiated water in the steam system is a personnel hazard at concentration levels well below one part per million and this level would soon be reached without costly isotopic processing. Alternatively, including a combination of permeation barriers on reactor and steam generator tubes and molten salt processing is estimated to reduce the leak rate into the steam system by over two orders of magnitude. For the option with the lowest estimated leak rate, 55 Ci/d, it may be possible to purge the steam system continuously to prevent tritiated water buildup. At best, isotopic separation of dilute tritiated water may not be necessary and for higher leak-rate options the isotopic processing rate can be reduced. The proposed permeation barrier for the reactor tubes is a 10 μm layer of tungsten which, in principle, will reduce tritium blanket permeation by a factor of about 300 below the bare-steel rate

Expansion of thermodynamic model of solute permeation through reverse osmosis membrane

International Nuclear Information System (INIS)

Nishimaki, Kenzo; Koyama, Akio

1994-01-01

Many studies have been performed on permeation mechanism of solute and solvent in membrane separation process like reverse osmosis or ultrafiltration, and several models of solute/solvent permeation through membrane are proposed. Among these models, Kedem and Katchalsky, based on the theory of thermodynamics of irreversible processes, formulated the one-solute permeation process in their mathematical model, which treats membrane as a black box, not giving consideration to membrane structure and to interaction between membrane material and permeates, viz. solute and solvent. According to this theory, the driving force of solute/solvent permeation through membrane is the difference of their chemical potential between both sides of membrane, and the linear phenomenological equation is applied to describing the relation between driving force and flux of solute/solvent. This equation can be applied to the irreversible process only when the process is almost in equilibrium. This condition is supposed to be satisfied in the solute/solvent permeation process through compact membrane with fine pores like reverse osmosis membrane. When reverse osmosis is applied to treatment process for liquid waste, which usually contains a lot of solutes as contaminants, we can not predict the behavior of contaminants by the above one-solute process model. In the case of multi-solutes permeation process for liquid waste, the number of parameter in thermodynamic model increases rapidly with the number of solute, because of coupling phenomenon among solutes. In this study, we expanded the above thermodynamic model to multi-solute process applying operational calculus to the differential equations which describe the irreversible process of the system, and expressed concisely solute concentration vector as a matrix product. In this way, we predict the behavior of solutes in multi-solutes process, using values of parameters obtained in two-solutes process. (author)

A simple, sensitive graphical method of treating thermogravimetric analysis data

Science.gov (United States)

Abraham Broido

1969-01-01

Thermogravimetric Analysis (TGA) is finding increasing utility in investigations of the pyrolysis and combustion behavior of materuals. Although a theoretical treatment of the TGA behavior of an idealized reaction is relatively straight-forward, major complications can be introduced when the reactions are complex, e.g., in the pyrolysis of cellulose, and when...

Oxygen permeation through oxygen ion oxide-noble metal dual phase composites

NARCIS (Netherlands)

Chen, C.S.; Chen, C.S.; Kruidhof, H.; Bouwmeester, Henricus J.M.; Verweij, H.; Burggraaf, Anthonie; Burggraaf, A.J.

1996-01-01

Oxygen permeation behaviour of three composites, yttria-stabilized zirconia-palladium, erbia-stabilized bismuth oxidenoble metal (silver, gold) was studied. Oxygen permeation measurements were performed under controlled oxygen pressure gradients at elevated temperatures. Air was supplied at one side

Formation of permeation barriers on ceramic SiC/SiC composites

International Nuclear Information System (INIS)

Racault, C.; Fenici, P.

1996-01-01

The effectiveness as permeation barriers of the following CVD and PVD (sputtering) coatings has been investigated: TiC+Al 2 O 3 (CVD), SiC(CVD), SiO 2 (CVD), TiN(CVD), TiN(CVD)+TiN(PVD) and SiC(CVD)+Al 2 O 3 (PVD). The substrate material was a SiC/SiC composite, proposed as low activation structural material for fusion applications. Permeation measurements were performed in the temperature range 300-750 K using deuterium at pressures in the range 0.5-150 kPa. A linear dependence of permeation rate on pressure was measured. The efficiency of the coatings as deuterium permeation barriers is discussed in terms of coating microstructure. The best result was obtained with a bilayer of TiN(CVD) (15 μm) +TiN(PVD) (8 μm). (orig.)

40 CFR 1060.521 - How do I test fuel caps for permeation emissions?

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false How do I test fuel caps for permeation... EQUIPMENT Test Procedures § 1060.521 How do I test fuel caps for permeation emissions? If you measure a fuel tank's permeation emissions with a nonpermeable covering in place of the fuel cap under § 1060.520(b)(5...

Permeation of deuterium implanted into V-15Cr-5Ti

International Nuclear Information System (INIS)

Anderl, R.A.; Longhurst, G.R.; Struttmann, D.A.

1987-01-01

Permeation and reemission of deuterium for the vanadium alloy, V-15Cr-5Ti, was investigated using 3 keV, D 3 + ion beams from a small accelerator. The experiments consisted of measurement of the deuterium reemission and permeation rates as a function of implantation fluence for 0.5 mm thick specimens heated to temperatures from 623 K to 823 K. Implantation-side surface characterization was made by simultaneous measurements of sputtered ions with a secondary ion mass spectrometer (SIMS). For the experimental conditions used, the steady-state deuterium permeation flux in V-15Cr-5Ti is approximately 18% of the implantation flux. This is approximately 1000 times that seen in the austenitic stainless steel, PCA, and 200 times that seen in the ferritic steel, HT-9, under comparable conditions. Measurement of deuterium diffusivity in V-15Cr-5Ti using permeation break-through times indicates that D = 1.4x10 -8 exp(-0.11 eV/kT)(m 2 /s), over the temperature range 723 K to 823 K. (orig.)

Permeation of deuterium implanted into V-15Cr-5Ti

Science.gov (United States)

Anderl, R. A.; Longhurst, G. R.; Struttmann, D. A.

1987-02-01

Permeation and reemission of deuterium for the vanadium alloy, V-15Cr-5Ti, was investigated using 3 keV, D 3+ ion beams from a small accelerator. The experiments consisted of measurement of the deuterium reemission and permeation rates as a function of implantation fluence for 0.5 mm thick specimens heated to temperatures from 623 K to 823 K. Implantation-side surface characterization was made by simultaneous measurements of sputtered ions with a secondary ion mass spectrometer (SIMS). For the experimental conditions used, the steady-state deuterium permeation flux in V-15Cr-5Ti is approximately 18% of the implantation flux. This is approximately 1000 times that seen in the austenitic stainless steel, PCA, and 200 times that seen in the ferritic steel, HT-9, under comparable conditions. Measurement of deuterium diffusivity in V-15Cr-5Ti using permeation break-through times indicates that D = 1.4 × 10 -8 exp( -0.11 eV/ kT) (m 2/s), over the temperature range 723 K to 823 K.

Permeation of deuterium implanted into V-15Cr-5Ti

Energy Technology Data Exchange (ETDEWEB)

Anderl, R.A.; Longhurst, G.R.; Struttmann, D.A.

1987-02-01

Permeation and reemission of deuterium for the vanadium alloy, V-15Cr-5Ti, was investigated using 3 keV, D/sub 3//sup +/ ion beams from a small accelerator. The experiments consisted of measurement of the deuterium reemission and permeation rates as a function of implantation fluence for 0.5 mm thick specimens heated to temperatures from 623 K to 823 K. Implantation-side surface characterization was made by simultaneous measurements of sputtered ions with a secondary ion mass spectrometer (SIMS). For the experimental conditions used, the steady-state deuterium permeation flux in V-15Cr-5Ti is approximately 18% of the implantation flux. This is approximately 1000 times that seen in the austenitic stainless steel, PCA, and 200 times that seen in the ferritic steel, HT-9, under comparable conditions. Measurement of deuterium diffusivity in V-15Cr-5Ti using permeation break-through times indicates that D = 1.4x10/sup -8/ exp(-0.11 eVkT)(m/sup 2/s), over the temperature range 723 K to 823 K.

The formation of hydrogen permeation barriers on steels by aluminising

Science.gov (United States)

Forcey, K. S.; Ross, D. K.; Wu, C. H.

1991-06-01

An extensive investigation has been carried out into the effectiveness of aluminised layers as permeation barriers on AISI 316L stainless and DIN 1.4914 martensitic steels. The study involved measurement of the hydrogen permeation rate through commercially aluminised steel discs of thicknesses in the range 1-1.6 mm, at temperatures between 250 and 600 °C and for an upstream hydrogen pressure of 10 5 Pa. The composition and structure of the aluminide layers were investigated by a number of techniques such as SEM, electron beam microprobe and X-ray diffraction. Accelerator based techniques such as RBS and NRA were employed to study the top micron or so of the surfaces of the samples. By these techniques it was found that the effectiveness of the permeation barrier depended on the formation of a thin surface oxide layer consisting of Al 2O 3. It was found that the permeation rate through the aluminised steels could be reduced by 3-4 orders of magnitude by forming a surface oxide layer up to a micron or so in thickness.

Mechanisms of oxygen permeation through plastic films and barrier coatings

Science.gov (United States)

Wilski, Stefan; Wipperfürth, Jens; Jaritz, Montgomery; Kirchheim, Dennis; Mitschker, Felix; Awakowicz, Peter; Dahlmann, Rainer; Hopmann, Christian

2017-10-01

Oxygen and water vapour permeation through plastic films in food packaging or other applications with high demands on permeation are prevented by inorganic barrier films. Most of the permeation occurs through small defects (visualized by etching with reactive oxygen in a capacitively coupled plasma and subsequent SEM imaging. In this work, defects in SiO x -coatings deposited by plasma-enhanced chemical vapour deposition on polyethylene terephthalate (PET) are investigated and the mass transport through the polymer is simulated in a 3D approach. Calculations of single defects showed that there is no linear correlation between the defect area and the resulting permeability. The influence of adjacent defects in different distances was observed and led to flow reduction functions depending on the defect spacing and defect area. A critical defect spacing where no interaction between defects occurs was found and compared to other findings. According to the superposition principle, the permeability of single defects was added up and compared to experimentally determined oxygen permeation. The results showed the same trend of decreasing permeability with decreasing defect densities.

Preventing method and device for underground permeation of hazardous material

International Nuclear Information System (INIS)

Funabashi, Kiyomi; Kurokawa, Hideaki; Fukazawa, Tetsuo; Yamazaki, Tadashi.

1996-01-01

In a method of preventing hazardous materials from permeating into ground by burying adsorbing materials underground, a plurality of adsorbing layers are laminated being spaced apart from each other, the concentration of the hazardous materials between each of the adsorbent layers is measured. When the concentration reaches a predetermined value, the adsorbent layers are regenerated. A suppression means for preventing hazardous materials from permeating into the ground are formed by an upper adsorbent layer and a lower adsorbent layer, and a means for measuring the concentration of hazardous materials passing through the upper adsorbent layer and a means for charging and discharging regenerated liquid are disposed. When it is detected that the poisonous materials can not be eliminated, the poisonous materials are already permeated to the adsorbent layer, and they start to inflow into underground water. In order to prevent it, an adsorbent layer is additionally disposed at the lower side of the place of detection to eliminate the poisonous materials completely thereby enabling to prevent poisonous materials from permeating into underground for a long period of time. (T.M.)

Deuterium permeation measurements on tungsten using ion-beam-based detection

Energy Technology Data Exchange (ETDEWEB)

Kapser, Stefan [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Physik-Department, Technische Universitaet Muenchen, James-Franck-Str. 1, 85748 Garching (Germany); Manhard, Armin; Toussaint, Udo von [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

2016-07-01

Tungsten (W) is promising for the inner wall of a future fusion reactor, where it will be exposed to high fluxes of hydrogen (H) isotopes. Knowledge of their diffusion in W is important for safety and economic considerations, particularly concerning tritium. A common method to investigate H diffusion in metals are permeation experiments. Typically, gas loading and mass-spectrometric detection are used. Information about the diffusion can be gained from the temporal evolution of the permeation flux, whose magnitude is determined by the permeability (product of diffusivity and solubility). However, for low-permeability metals, the permeation flux can be unmeasurably small. For W this is the case near room temperature. We present a method that circumvents this problem. It is an improved version of experiments on nickel and stainless steel. The W is exposed to deuterium (D) plasma on one side and the permeating D is accumulated in a getter on the other side. A cover prevents D gettering from the gas phase. The amount in the getter is analysed by the nuclear reaction D({sup 3}He,p){sup 4}He.

Permeation Barrier Coatings for the Helical Heat Exchanger

International Nuclear Information System (INIS)

Korinko, P.S.

1999-01-01

A permeation barrier coating was specified for the Helical Heat Exchanger (HHE) to minimize contamination through emissions and/or permeation into the nitrogen system for ALARA reasons. Due to the geometry of the HHE, a special coating practice was needed since the conventional method of high temperature pack aluminization was intractable. A survey of many coating companies was undertaken; their coating capabilities and technologies were assessed and compared to WSRC needs. The processes and limitations to coating the HHE are described. Slurry coating appears to be the most technically sound approach for coating the HHE

Permeation of "Hydromer" Film: An Elastomeric Hydrogen-Capturing Biopolymer.

Energy Technology Data Exchange (ETDEWEB)

Karnesky, Richard A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Friddle, Raymond William [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Whaley, Josh A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Smith, Geoffrey [New Mexico State Univ., Las Cruces, NM (United States)

2015-12-01

This report analyzes the permeation resistance of a novel and proprietary polymer coating for hydrogen isotope resistance that was developed by New Mexico State University. Thermal gravimetric analysis and thermal desoprtion spectroscopy show the polymer is stable thermally to approximately 250 deg C. Deuterium gas-driven permeation experiments were conducted at Sandia to explore early evidence (obtained using Brunauer - Emmett - Teller) of the polymer's strong resistance to hydrogen. With a relatively small amount of the polymer in solution (0.15%), a decrease in diffusion by a factor of 2 is observed at 100 and 150 deg C. While there was very little reduction in permeability, the preliminary findings reported here are meant to demonstrate the sensitivity of Sandia's permeation measurements and are intended to motivate the future exploration of thicker barriers with greater polymer coverage.

Computational investigation of the effects of barrier layers on the permeation of hydrogen through metals

International Nuclear Information System (INIS)

Perkins, W.G.

1975-01-01

Results of a computational investigation of the permeation behavior of oxide-coated metal membranes are presented. A steady-state permeation model was developed which promises to be useful in evaluation of oxide layers on metals as hydrogen permeation barriers. The pressure and thickness dependence of steady state permeation through oxide-coated metal membranes is described using plots of logarithmic functions. (U.S.)

Increased albumin permeation in eyes, aorta, and kidney of hypertensive rats fed galactose

International Nuclear Information System (INIS)

Tilton, R.G.; LaRose, L.; Chang, K.; Weigel, C.J.; Williamson, J.R.

1986-01-01

These experiments were undertaken to determine whether ingestion of galactose increases albumin permeation in the vasculature of hypertensive rats. 50% dextrin (control) or 50% galactose diets were fed to unilaterally nephrectomized, male Sprague-Dawley rats weighing 200 g. Hypertension (systolic pressure >175 mmHg) was induced by weekly IM injections of 25 mg/kg DOCA and 1% saline drinking water; 3 months later 125 I-albumin permeation was assessed in whole eyes, aorta and kidneys. 125 I-albumin permeation was significantly increased in all 3 tissues of hypertensive rats (n = 9) vs controls (n = 9): aorta (3.30 +/- 0.19 (SD) vs 2.87 +/- 0.14), eye (3.15 +/- 0.14 vs 2.59 +/- 0.11), and kidney (6.58 +/- 0.63 vs 3.85 +/- 0.50). Albumin permeation was increased still further in hypertensive rats fed the galactose diet (n = 8): aorta (3.75 +/- 0.38), eye (3.82 +/- 0.17), and kidney (10.74 +/- 3.13). Hypertension +/- galactose feeding had no effect on albumin permeation in lung, skin, or brain. These findings indicate that: (1) hypertension increases albumin permeation in vessels affected by diabetic vascular diseases, and 2) hypertension-induced increases in albumin permeation are increased still further by galactose ingestion, presumably mediated by imbalances in polyol/insitol metabolism (analogous to those induced by diabetes) independent of hyperglycemia and/or insulinopenia

Ultrathin graphene-based membrane with precise molecular sieving and ultrafast solvent permeation

Science.gov (United States)

Yang, Q.; Su, Y.; Chi, C.; Cherian, C. T.; Huang, K.; Kravets, V. G.; Wang, F. C.; Zhang, J. C.; Pratt, A.; Grigorenko, A. N.; Guinea, F.; Geim, A. K.; Nair, R. R.

2017-12-01

Graphene oxide (GO) membranes continue to attract intense interest due to their unique molecular sieving properties combined with fast permeation. However, their use is limited to aqueous solutions because GO membranes appear impermeable to organic solvents, a phenomenon not yet fully understood. Here, we report efficient and fast filtration of organic solutions through GO laminates containing smooth two-dimensional (2D) capillaries made from large (10-20 μm) flakes. Without modification of sieving characteristics, these membranes can be made exceptionally thin, down to ~10 nm, which translates into fast water and organic solvent permeation. We attribute organic solvent permeation and sieving properties to randomly distributed pinholes interconnected by short graphene channels with a width of 1 nm. With increasing membrane thickness, organic solvent permeation rates decay exponentially but water continues to permeate quickly, in agreement with previous reports. The potential of ultrathin GO laminates for organic solvent nanofiltration is demonstrated by showing >99.9% rejection of small molecular weight organic dyes dissolved in methanol. Our work significantly expands possibilities for the use of GO membranes in purification and filtration technologies.

Determination of solvents permeating through chemical protective clothing with a microsensor array.

Science.gov (United States)

Park, J; Zellers, E T

2000-08-01

The performance of a novel prototype instrument in determining solvents and solvent mixtures permeating through samples of chemical protective clothing (CPC) materials was evaluated. The instrument contains a mini-preconcentrator and an array of three polymer-coated surface-acoustic-wave (SAW) microsensors whose collective response patterns are used to discriminate among multiple permeants. Permeation tests were performed with a 2.54 cm diameter test cell in an open-loop configuration on samples of common glove materials challenged with four individual solvents, three binary mixtures, and two ternary mixtures. Breakthrough times, defined as the times required for the permeation rate to reach a value of 1 microg cm(-2) min(-1), determined by the instrument were within 3 min of those determined in parallel by manual sampling and gas chromatographic analysis. Permeating solvents were recognized (identified) from their response patterns in 59 out of 64 measurements (92%) and their vapor concentrations were quantified to an accuracy of +/- 31% (typically +/- 10%). These results demonstrate the potential for such instrumentation to provide semi-automated field or bench-top screening of CPC permeation resistance.

Impacts of chemical enhancers on skin permeation and deposition of terbinafine.

Science.gov (United States)

Erdal, Meryem Sedef; Peköz, Ayca Yıldız; Aksu, Buket; Araman, Ahmet

2014-08-01

The addition of chemical enhancers into formulations is the most commonly employed approach to overcome the skin barrier. The objective of this work was to evaluate the effect of vehicle and chemical enhancers on the skin permeation and accumulation of terbinafine, an allylamine antifungal drug. Terbinafine (1% w/w) was formulated as a Carbopol 934 P gel formulation in presence and absence of three chemical enhancers, nerolidol, dl-limonene and urea. Terbinafine distribution and deposition in stratum corneum (SC) and skin following 8-h ex vivo permeation study was determined using a sequential tape stripping procedure. The conformational order of SC lipids was investigated by ATR-FTIR spectroscopy. Nerolidol containing gel formulation produced significantly higher enhancement in terbinafine permeation through skin and its skin accumulation was increased. ATR-FTIR results showed enhancer induced lipid bilayer disruption in SC. Urea resulted in enhanced permeation of terbinafine across the skin and a balanced distribution to the SC was achieved. But, dl-limonene could not minimize the accumulation of terbinafine in the upper SC. Nerolidol dramatically improved the skin permeation and deposition of terbinafine in the skin that might help to optimize targeting of the drug to the epidermal sites as required for both of superficial and deep cutaneous fungal infections.

Comparison of implantation-driven permeation characteristics of fusion reactor structural materials

International Nuclear Information System (INIS)

Longhurst, G.R.; Anderl, R.A.; Struttmann, D.A.

1986-01-01

Implantation-driven permeation experiments have been conducted on samples of the ferritic steel HT-9, the austenitic Primary Candidate Alloy (PCA) and the vanadium alloy V-15Cr-5Ti using D 3 + ions under conditions that simulate charge-exchange neutral loading on a fusion reactor first wall. The steels all exhibited an initially intense permeation ''spike'' followed by an exponential decrease to low steady-state values. That spike was not evident in the V-15Cr-5Ti experiments. Steady-state permeation was highest in the vanadium alloy and lowest in the austenitic steel. Though permeation rates in the HT-9 were lower than those in V-15Cr-5Ti, permeation transients were much faster in HT-9 than in other materials tested. Ion-beam sputtering of the surface in the steel experiments resulted in enhanced remission at the front surface, whereas in the vanadium tests, recombination and diffusivity both appeared to diminish as the deuterium concentration rose. This may be due to a phase change in the material. We conclude that for conditions comparable to those of these experiments, tritium retention and loss in first wall structures made of steels will be less than in structures made of V-15Cr-5Ti

Hydrogen permeation modification of 4140 steel by ion nitriding with pulsed plasmas

Energy Technology Data Exchange (ETDEWEB)

Bruzzoni, P.; Ortiz, M. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Bruehl, S.P.; Gomez, B.J.A.; Feugeas, J.N. [Inst. de Fisica Rosario (UNR-CONICET), Rosario (Argentina); Nosei, L. [Inst. de Mecanica Aplicada y Estructuras (UNR), Rosario (Argentina)

1998-11-10

It is widely known that the hydrogen in steel produces embrittlement. This effect may cause the failure of the elements (confining walls, mechanical parts, etc.) whose surfaces are in contact with this gas or with processes in which hydrogen is continuously generated. In this work it is shown that the ion nitriding of the surface of AISI 4140 is a good mechanism to act as a barrier against hydrogen permeation in its bulk. The ion nitriding was performed using a square wave DC glow discharge. The development of a compound layer of iron nitrides was observed as the cause of the hydrogen permeation reduction. For equal duration of treatment, thicker compound layers were developed in higher discharge/post-discharge ratios in the square wave of the applied voltage onto the sample (cathode), with a greater reduction of hydrogen permeation coefficient as a consequence. Nevertheless, the permeation was not reduced to zero in any of the treatment conditions used. The results of the analysis of the permeation tests and the image of the photomicrographs showed that the existence of cracks, fractures, failures, etc. in the compound layer (pre-existing in the AISI 4140 steel) could be the cause of the residual hydrogen permeation. This can be attributed to the movement of the hydrogen through these defects diffusing through the original {alpha}-Fe phase of the non-treated steel. (orig.) 11 refs.

Rapid Screening of Bovine Milk Oligosaccharides in a Whey Permeate Product and Domestic Animal Milks by Accurate Mass Database and Tandem Mass Spectral Library

Science.gov (United States)

Lee, Hyeyoung; Cuthbertson, Daniel J.; Otter, Don E.; Barile, Daniela

2018-01-01

A bovine milk oligosaccharide (BMO) library, prepared from cow colostrum, with 34 structures was generated and used to rapidly screen oligosaccharides in domestic animal milks and a whey permeate powder. The novel library was entered into a custom Personal Compound Database and Library (PCDL) and included accurate mass, retention time, and tandem mass spectra. Oligosaccharides in minute-sized samples were separated using nanoliquid chromatography (nanoLC) coupled to a high resolution and sensitive quadrupole-Time of Flight (Q-ToF) MS system. Using the PCDL, 18 oligosaccharides were found in a BMO-enriched product obtained from whey permeate processing. The usefulness of the analytical system and BMO library was further validated using milks from domestic sheep and buffaloes. Through BMO PCDL searching, 15 and 13 oligosaccharides in the BMO library were assigned in sheep and buffalo milks, respectively, thus demonstrating significant overlap between oligosaccharides in bovine (cow and buffalo) and ovine (sheep) milks. This method was shown to be an efficient, reliable, and rapid tool to identify oligosaccharide structures using automated spectral matching. PMID:27428379

Automation of a thermogravimetric equipment

International Nuclear Information System (INIS)

Mussio, L.; Castiglioni, J.; Diano, W.

1987-01-01

A low cost automation of some instruments by means of simple electronic circuits and a microcomputer Apple IIe. type is discussed. The electronic circuits described are: a) a position detector including phototransistors connected as differential amplifier; b) a current source that, using the error signal of the position detector, changes the current through the coil of an electromagnetic balance to restore its zero position; c) a proportional temperature controller, zero volt switching to drive a furnace to a desired temperature; d) an interface temperature regulator-microcomputer to control the temperature regulator by software; e) a multiplexer for an analog input of a commercial interface. Those circuits are applied in a thermogravimetric equipment used also for vapours adsorption. A program in block diagram form is included and is able to record change of mass, time, furnace temperature and to drive the temperature regulator in order to have the heating rates or the temperature plateaux needed for the experiment. (author) [pt

In vitro-in vivo correlation in skin permeation.

Science.gov (United States)

Mohammed, D; Matts, P J; Hadgraft, J; Lane, M E

2014-02-01

In vitro skin permeation studies have been used extensively in the development and optimisation of delivery of actives in vivo. However, there are few reported correlations of such in vitro studies with in vivo data. The aim of this study was to investigate the skin permeation of a model active, niacinamide, both in vitro and in vivo. Conventional diffusion cell studies were conducted in human skin to determine niacinamide permeation from a range of vehicles which included dimethyl isosorbide (DMI), propylene glycol (PG), propylene glycol monolaurate (PGML), N-methyl 2-pyrrolidone (NMP), Miglyol 812N® (MG), and mineral oil (MO). Single, binary or ternary systems were examined. The same vehicles were subsequently examined to investigate niacinamide delivery in vivo. For this proof-of-concept study one donor was used for the in vitro studies and one volunteer for the in vivo investigations to minimise biovariability. Analysis of in vitro samples was conducted using HPLC and in vivo uptake of niacinamide was evaluated using Confocal Raman spectroscopy (CRS). The amount of niacinamide permeated through skin in vitro was linearly proportional to the intensity of the niacinamide signal determined in the stratum corneum in vivo. A good correlation was observed between the signal intensities of selected vehicles and niacinamide signal intensity. The findings provide further support for the use of CRS to monitor drug delivery into and across the skin. In addition, the results highlight the critical role of the vehicle and its disposition in skin for effective dermal delivery.

Development of a plasma driven permeation experiment for TPE

Energy Technology Data Exchange (ETDEWEB)

Buchenauer, Dean, E-mail: dabuche@sandia.gov [Sandia National Laboratories, Livermore, CA (United States); Kolasinski, Robert [Sandia National Laboratories, Livermore, CA (United States); Shimada, Masa [Idaho National Laboratory, Idaho Falls, ID (United States); Donovan, David [Sandia National Laboratories, Livermore, CA (United States); Youchison, Dennis [Sandia National Laboratories, Albuquerque, NM (United States); Merrill, Brad [Idaho National Laboratory, Idaho Falls, ID (United States)

2014-10-15

Highlights: • We have designed and fabricated a novel tritium permeation membrane holder for use in the Tritium Plasma Experiment (TPE). • The membrane temperature is controlled by varying the cooling flow rate and proximity of a spiral cooling channel. • Sealing tests have demonstrated adequate helium leak rates up to temperatures of 1000 °C. • Flow modeling indicates a minimal helium pressure drop across the membrane holder (<700 Pa). • Thermal modeling shows good heat removal and minimal membrane temperature variation (±2%) even up to peak TPE ion fluxes. - Abstract: Experiments on retention of hydrogen isotopes (including tritium) at temperatures less than 800 °C have been carried out in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory [1,2]. To provide a direct measurement of plasma driven permeation in plasma facing materials at temperatures reaching 1000 °C, a new TPE membrane holder has been built to hold test specimens (≤1 mm in thickness) at high temperature while measuring tritium permeating through the membrane from the plasma facing side. This measurement is accomplished by employing a carrier gas that transports the permeating tritium from the backside of the membrane to ion chambers giving a direct measurement of the plasma driven tritium permeation rate. Isolation of the membrane cooling and sweep gases from TPE's vacuum chamber has been demonstrated by sealing tests performed up to 1000 °C of a membrane holder design that provides easy change out of membrane specimens between tests. Simulations of the helium carrier gas which transports tritium to the ion chamber indicate a very small pressure drop (∼700 Pa) with good flow uniformity (at 1000 sccm). Thermal transport simulations indicate that temperatures up to 1000 °C are expected at the highest TPE fluxes.

Development of a plasma driven permeation experiment for TPE

International Nuclear Information System (INIS)

Buchenauer, Dean; Kolasinski, Robert; Shimada, Masa; Donovan, David; Youchison, Dennis; Merrill, Brad

2014-01-01

Highlights: • We have designed and fabricated a novel tritium permeation membrane holder for use in the Tritium Plasma Experiment (TPE). • The membrane temperature is controlled by varying the cooling flow rate and proximity of a spiral cooling channel. • Sealing tests have demonstrated adequate helium leak rates up to temperatures of 1000 °C. • Flow modeling indicates a minimal helium pressure drop across the membrane holder (<700 Pa). • Thermal modeling shows good heat removal and minimal membrane temperature variation (±2%) even up to peak TPE ion fluxes. - Abstract: Experiments on retention of hydrogen isotopes (including tritium) at temperatures less than 800 °C have been carried out in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory [1,2]. To provide a direct measurement of plasma driven permeation in plasma facing materials at temperatures reaching 1000 °C, a new TPE membrane holder has been built to hold test specimens (≤1 mm in thickness) at high temperature while measuring tritium permeating through the membrane from the plasma facing side. This measurement is accomplished by employing a carrier gas that transports the permeating tritium from the backside of the membrane to ion chambers giving a direct measurement of the plasma driven tritium permeation rate. Isolation of the membrane cooling and sweep gases from TPE's vacuum chamber has been demonstrated by sealing tests performed up to 1000 °C of a membrane holder design that provides easy change out of membrane specimens between tests. Simulations of the helium carrier gas which transports tritium to the ion chamber indicate a very small pressure drop (∼700 Pa) with good flow uniformity (at 1000 sccm). Thermal transport simulations indicate that temperatures up to 1000 °C are expected at the highest TPE fluxes

Heater-Integrated Cantilevers for Nano-Samples Thermogravimetric Analysis

Science.gov (United States)

Toffoli, Valeria; Carrato, Sergio; Lee, Dongkyu; Jeon, Sangmin; Lazzarino, Marco

2013-01-01

The design and characteristics of a micro-system for thermogravimetric analysis (TGA) in which heater, temperature sensor and mass sensor are integrated into a single device are presented. The system consists of a suspended cantilever that incorporates a microfabricated resistor, used as both heater and thermometer. A three-dimensional finite element analysis was used to define the structure parameters. TGA sensors were fabricated by standard microlithographic techniques and tested using milli-Q water and polyurethane microcapsule. The results demonstrated that our approach provides a faster and more sensitive TGA with respect to commercial systems.

Thermogravimetric study of rare earth concentrates

International Nuclear Information System (INIS)

Delyagejd, V.V.; Anisimova, V.N.; Eremenko, Z.V.; Kutsev, V.S.

1974-01-01

Methods of thermogravimetric, chemical and phase analysis were used in measuring the concentration of rare-earth elements of different origins. At temperatures 400-800 deg C a gradual decomposition of fluorocarbonates takes place leading to the formation of derivatives of corresponding oxides and oxyfluorides. For concentrates containing siderite the process takes place at 550-600 deg C followed by oxidation of bivalent iron into trivalent state. Reaction of rare-earth elements with sodium carbonate and the increase in the concentration of the latter results in a narrowing down of the interval of temperatures at which decomposition takes place. Under these conditions an intense reaction and a fusion take place leading to the formation of eutectic at 500-600 deg C and further synthesis of sodium fluoride and oxyfluoride derivatives of calcium and rare-earth elements

Thermogravimetric studies of New Zealand coals

Energy Technology Data Exchange (ETDEWEB)

Beamish, B.B.; Rodgers, K.A.; Benfell, K.E.; Shaw, K.J. [University of Auckland, Auckland (New Zealand). Dept. of Geology

1997-12-31

The thermal behaviour of New Zealand coals may be reliably characterised by a series of tightly constrained thermogravimetric (TG) procedures of high repeatability developed in the Department of Geology at The University of Auckland. Proximate, combustion and char reactivity analyses can be routinely obtained for run-of-mine samples. Volatile matter determination by TG produces an acceptable reproducible result compared with the ISO method, whereas further refinement of the technique is necessary to achieve the same level of precision for ash content of New Zealand low rank coals. Combining combustion and char reactivity analyses enables the performance of a coal to be assessed under differing operating conditions, and offers the opportunity to elucidate competing effects of major element geochemistry of the coal. 12 refs., 4 figs., 2 tabs.

Water Vapor Permeation of Metal Oxide/Polymer Coated Plastic Films

Science.gov (United States)

Numata, Yukihiro; Oya, Toshiyuki; Kuwahara, Mitsuru; Ito, Katsuya

Barrier performance to water vapor permeation of ceramic coated layers deposited on flexible polymer films is of great interest to food packaging, medical device packaging and flat panel display industries. In this study, a new type film in which a ceramic layer is deposited on a polymer coated film was proposed for lower water vapor permeation. It is important how to control interfacial properties between each layer and film for good barrier performance. Several kinds of polymer coated materials were prepared for changing surface free energy of the films before and after depositing the ceramic layer. The ceramic layer, which is composed of mixed material of SiO2 and Al2O3, was adopted under the same conditions. The following results were obtained; 1) Water vapor permeation is not related to the surface energy of polymer coated films, 2) After depositing the ceramic layer, however, a strong correlation is observed between the water vapor permeation and surface free energy. 3) The phenomenon is considered that the polarity of the polymer layers plays a key role in changing the structure of ceramic coated layers.

Mechanisms of oxygen permeation through plastic films and barrier coatings

International Nuclear Information System (INIS)

Wilski, Stefan; Wipperfürth, Jens; Jaritz, Montgomery; Kirchheim, Dennis; Dahlmann, Rainer; Hopmann, Christian; Mitschker, Felix; Awakowicz, Peter

2017-01-01

Oxygen and water vapour permeation through plastic films in food packaging or other applications with high demands on permeation are prevented by inorganic barrier films. Most of the permeation occurs through small defects (<3 µ m) in the barrier coating. The defects were visualized by etching with reactive oxygen in a capacitively coupled plasma and subsequent SEM imaging. In this work, defects in SiO x -coatings deposited by plasma-enhanced chemical vapour deposition on polyethylene terephthalate (PET) are investigated and the mass transport through the polymer is simulated in a 3D approach. Calculations of single defects showed that there is no linear correlation between the defect area and the resulting permeability. The influence of adjacent defects in different distances was observed and led to flow reduction functions depending on the defect spacing and defect area. A critical defect spacing where no interaction between defects occurs was found and compared to other findings. According to the superposition principle, the permeability of single defects was added up and compared to experimentally determined oxygen permeation. The results showed the same trend of decreasing permeability with decreasing defect densities. (paper)

In vitro permeation of platinum and rhodium through Caucasian skin.

Science.gov (United States)

Franken, A; Eloff, F C; Du Plessis, J; Badenhorst, C J; Jordaan, A; Du Plessis, J L

2014-12-01

During platinum group metals (PGMs) refining the possibility exists for dermal exposure to PGM salts. The dermal route has been questioned as an alternative route of exposure that could contribute to employee sensitisation, even though literature has been focused on respiratory exposure. This study aimed to investigate the in vitro permeation of platinum and rhodium through intact Caucasian skin. A donor solution of 0.3mg/ml of metal, K2PtCl4 and RhCl3 respectively, was applied to the vertical Franz diffusion cells with full thickness abdominal skin. The receptor solution was removed at various intervals during the 24h experiment, and analysed with high resolution ICP-MS. Skin was digested and analysed by ICP-OES. Results indicated cumulative permeation with prolonged exposure, with a significantly higher mass of platinum permeating after 24h when compared to rhodium. The mass of platinum retained inside the skin and the flux of platinum across the skin was significantly higher than that of rhodium. Permeated and skin retained platinum and rhodium may therefore contribute to sensitisation and indicates a health risk associated with dermal exposure in the workplace. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation, thermogravimetric study and infrared spectra of rare earth acetates

International Nuclear Information System (INIS)

Graehlert, X.; Starke, M.

1992-01-01

The anhydrous and the hydrated acetates of Ho, Er, Tm, Yb and Lu have been prepared. The compounds obtained have been investigated by thermogravimetric analysis and infrared spectroscopy. The thermal decomposition of the rare earth acetates may proceed via various steps. It depends on both the number of crystal water molecules in the acetates and the rare earth element's behaviour. (orig.)

Assessment of permeation of lipoproteins in human carotid tissue

Science.gov (United States)

Ghosn, Mohamad G.; Syed, Saba H.; Leba, Michael; Morrisett, Joel D.; Tuchin, Valery V.; Larin, Kirill V.

2010-02-01

Cardiovascular disease is among the leading causes of death in the United States. Specifically, atherosclerosis is an increasingly devastating contributor to the tally and has been found to be a byproduct of arterial permeability irregularities in regards to lipoprotein penetration. To further explore arterial physiology and molecular transport, the imaging technique of Optical Coherence Tomography (OCT) was employed. With OCT, the permeation of glucose (MW = 180 Da), low density lipoprotein (LDL; MW = 2.1 × 106 Da), and high density lipoprotein (HDL; MW = 2.5 × 105 Da) in human carotid tissue was studied to determine the effect of different molecular characteristics on permeation in atherosclerotic tissues. The permeability rates calculated from the diffusion of the molecular agents into the abnormal carotid tissue samples is compared to those of normal, healthy tissue. The results show that in the abnormal tissue, the permeation of agents correlate to the size constraints. The larger molecules of LDL diffuse the slowest, while the smallest molecules of glucose diffuse the fastest. However, in normal tissue, LDL permeates at a faster rate than the other two agents, implying the existence of a transport mechanism that facilitates the passage of LDL molecules. These results highlight the capability of OCT as a sensitive and specific imaging technique as well as provide significant information to the understanding of atherosclerosis and its effect on tissue properties.

Synthesis and characterization of acrylate copolymer containing fluorescein functional group

International Nuclear Information System (INIS)

Hui, Guodong; Huang, Weiyun; Song, Yunzhao; Chen, Deben; Zhong, Anyong

2013-01-01

We report a novel method to fabricate fluorescent polymer (F-CPA) based on the esterification between acrylate copolymer (CPA) and fluorescein using N, N-dicyclohexylcarbodiimide (DCC)/4-dimethylaminopyridine (DMAP) as catalyst. The resulting copolymer was characterized by Fourier transform-infrared spectroscopy (FT-IR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), ultraviolet-visible spectroscopy (UV-Vis) and fluorescence spectroscopy. In addition, the influences of concentration, solvents, pH and metal cations (Cu"2"+, Fe"3"+ and Zn"2"+) on the fluorescent behaviors of F-CPA are discussed in detail. All those observations suggest that the synthesized F-CPA is an excellent luminescent macromolecular material with simple synthesis method and excellent solubility. Moreover, its sensitive fluorescence response behaviors to solvents, pH and metal cations make it to become a polymer-based probe

Dominant thermogravimetric signatures of lignin in cashew shell as compared to cashew shell cake.

Science.gov (United States)

Gangil, Sandip

2014-03-01

Dominant thermogravimetric signatures related to lignin were observed in cashew shell as compared to these signatures in cashew shell cake. The phenomenon of weakening of lignin from cashew shell to cashew shell cake was explained on the basis of changes in the activation energies. The pertinent temperature regimes responsible for the release of different constituents of both the bio-materials were identified and compared. The activation energies of cashew shell and cashew shell cake were compared using Kissinger-Akahira-Sunose method. Thermogravimetric profiling of cashew shell and cashew shell cake indicated that these were different kinds of bio-materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of argon ion sputtering of surface on hydrogen permeation through vanadium

International Nuclear Information System (INIS)

Yamawaki, Michio; Namba, Takashi; Yoneoka, Toshiaki; Kanno, Masayoshi; Shida, Koji.

1983-01-01

In order to measure the hydrogen permeation rate through V with atomically cleaned surface, an Ar ion sputtering apparatus has been installed in the hydrogen permeability measuring system. The permeation rate of the initial specimen was found to be increased by about one order of magnitude after Ar ion sputtering of its upstream side surface. Repeating of such a sputter-cleaning was not so much effective in increasing the steady state permeation rate as the initial sputtering was, but it accelerated the transient response rate by a factor of 2 or 3. The transient response rate was also accelerated by the increase of hydrogen pressure, but this effect tended to be diminished by the sputter-cleaning of specimen surface. The surface impurity layer on the downstream side of specimen was also inferred to act as a diffusion barrier affecting the steady state permeation rate. The present value of activation energy for hydrogen permeation through V at temperatures below 873K was the smallest one ever obtained, showing that the surface effect was minimized in the present study on account of the surface sputter-cleaning in addition to the ultra high vacuum system. (author)

Control of tritium permeation through fusion reactor strucural materials

International Nuclear Information System (INIS)

Maroni, V.A.

1978-01-01

The intention of this paper is to provide a brief synopsis of the status of understanding and technology pertaining to the dissolution and permeation of tritium in fusion reactor materials. The following sections of this paper attempt to develop a simple perspective for understanding the consequences of these phenomena and the nature of the technical methodology being contemplated to control their impact on fusion reactor operation. Considered in order are: (1) the occurrence of tritium in the fusion fuel cycle, (2) a set of tentative criteria to guide the analysis of tritium containment and control strategies, (3) the basic mechanisms by which tritium may be released from a fusion plant, and (4) the methods currently under development to control the permeation-related release mechanisms. To provide background and support for these considerations, existing solubility and permeation data for the hydrogen isotopes are compared and correlated under conditions to be expected in fusion reactor systems

RF plasma-driven hydrogen permeation through a biased iron membrane

International Nuclear Information System (INIS)

Banno, T.; Waelbroeck, F.; Winter, J.

1984-01-01

The steady-state RF plasma-driven hydrogen permeation through an electrically biased iron membrane has been investigated as a function of the bias potential Vsub(M) for membrane temperatures in the range of 150-400 0 C. Vsub(M) has been gradually increased positively from the floating potential of the membrane. The permeation flux decreases when Vsub(M) increases at low voltages: positive hydrogen ions are repelled. The membrane temperature does not influence this effect measurably. The permeation flux starts to increase when Vsub(M) is raised higher, i.e. when energetic electrons strike the surface. This phenomenon shows a pronounced temperature dependence - the enhancement is largest for the lowest temperatures. The effect is interpreted in terms of an electron-induced dissociation of hydrogen molecules on the membrane surface. (orig.)

Permeation of macromolecules into the renal glomerular basement membrane and capture by the tubules

Science.gov (United States)

Lawrence, Marlon G.; Altenburg, Michael K.; Sanford, Ryan; Willett, Julian D.; Bleasdale, Benjamin; Ballou, Byron; Wilder, Jennifer; Li, Feng; Miner, Jeffrey H.; Berg, Ulla B.; Smithies, Oliver

2017-01-01

How the kidney prevents urinary excretion of plasma proteins continues to be debated. Here, using unfixed whole-mount mouse kidneys, we show that fluorescent-tagged proteins and neutral dextrans permeate into the glomerular basement membrane (GBM), in general agreement with Ogston's 1958 equation describing how permeation into gels is related to molecular size. Electron-microscopic analyses of kidneys fixed seconds to hours after injecting gold-tagged albumin, negatively charged gold nanoparticles, and stable oligoclusters of gold nanoparticles show that permeation into the lamina densa of the GBM is size-sensitive. Nanoparticles comparable in size with IgG dimers do not permeate into it. IgG monomer-sized particles permeate to some extent. Albumin-sized particles permeate extensively into the lamina densa. Particles traversing the lamina densa tend to accumulate upstream of the podocyte glycocalyx that spans the slit, but none are observed upstream of the slit diaphragm. At low concentrations, ovalbumin-sized nanoparticles reach the primary filtrate, are captured by proximal tubule cells, and are endocytosed. At higher concentrations, tubular capture is saturated, and they reach the urine. In mouse models of Pierson’s or Alport’s proteinuric syndromes resulting from defects in GBM structural proteins (laminin β2 or collagen α3 IV), the GBM is irregularly swollen, the lamina densa is absent, and permeation is increased. Our observations indicate that size-dependent permeation into the lamina densa of the GBM and the podocyte glycocalyx, together with saturable tubular capture, determines which macromolecules reach the urine without the need to invoke direct size selection by the slit diaphragm. PMID:28246329

Tritium permeation evaluation through vertical target of divertor based on recent tritium transport properties

International Nuclear Information System (INIS)

Nakamura, Hirofumi; Nishi, Masataka

2003-11-01

Re-evaluation of tritium permeation through vertical target of divertor under the ITER operation condition was carried out using tritium properties in the candidate materials such as the diffusion coefficient and the trapping factors in tungsten for armor, and the surface recombination coefficient on copper for the heat sink obtained by authours' recent investigation (authors' data), which simulated the plasma-facing conditions of ITER. Evaluation with the data set of previous evaluation was also carried out for comparison (previous data). The permeation analysis was carried out individually by classifying into the armor region (Carbon Fiber Composites and tungsten) and the slit region without armor (3% of armor surface area) assuming the incident flux and temperature for each region. As the results of the permeation analysis, estimated permeation amount with the authors' data was one order less than that with the previous data at the end of lifetime of the divertor due to authors' small diffusion coefficient of tritium in tungsten. It also indicated the possibility that permeation through the slit region of the armor tiles could dominate total permeation through the vertical target, since tritium permeation amount through tungsten armor with the authors' data was estimated to be reduced drastically smaller than that with the previous evaluation data. The result of a little tritium permeation amount through the vertical target with the authors' data ensured the conservatism of the current evaluation of tritium concentration in the primary cooling water in ITER divertor, as it indicated the possibility of direct drainage of the divertor primary cooling water. (author)

A permeation theory for single-file ion channels: one- and two-step models.

Science.gov (United States)

Nelson, Peter Hugo

2011-04-28

How many steps are required to model permeation through ion channels? This question is investigated by comparing one- and two-step models of permeation with experiment and MD simulation for the first time. In recent MD simulations, the observed permeation mechanism was identified as resembling a Hodgkin and Keynes knock-on mechanism with one voltage-dependent rate-determining step [Jensen et al., PNAS 107, 5833 (2010)]. These previously published simulation data are fitted to a one-step knock-on model that successfully explains the highly non-Ohmic current-voltage curve observed in the simulation. However, these predictions (and the simulations upon which they are based) are not representative of real channel behavior, which is typically Ohmic at low voltages. A two-step association/dissociation (A/D) model is then compared with experiment for the first time. This two-parameter model is shown to be remarkably consistent with previously published permeation experiments through the MaxiK potassium channel over a wide range of concentrations and positive voltages. The A/D model also provides a first-order explanation of permeation through the Shaker potassium channel, but it does not explain the asymmetry observed experimentally. To address this, a new asymmetric variant of the A/D model is developed using the present theoretical framework. It includes a third parameter that represents the value of the "permeation coordinate" (fractional electric potential energy) corresponding to the triply occupied state n of the channel. This asymmetric A/D model is fitted to published permeation data through the Shaker potassium channel at physiological concentrations, and it successfully predicts qualitative changes in the negative current-voltage data (including a transition to super-Ohmic behavior) based solely on a fit to positive-voltage data (that appear linear). The A/D model appears to be qualitatively consistent with a large group of published MD simulations, but no

Thermogravimetric and nuclear magnetic resonance study of hydrated Na-β''-alumina

International Nuclear Information System (INIS)

Donoso, P.; Panepucci, H.; Gobato, Y.G.; Oliveira, L.N.; Souza, D.P.F. de

1990-01-01

This paper reports thermogravimetric and proton spin-lattice relaxation times measurement of hydrated Na-β''-alumina, which yield information about the identification of the sites where the loosely bound water molecules are located in the polycrystalline sample. It examines also the influence of impurities on the motion of the protons. (autor) [pt

Strategy for thermo-gravimetric analysis of K East fuel samples

International Nuclear Information System (INIS)

Lawrence, L.A.

1997-01-01

A strategy was developed for the Thermo-Gravimetric Analysis (TGA) testing of K East fuel samples for oxidation rate determinations. Tests will first establish if there are any differences for dry air oxidation between the K West and K East fuel. These tests will be followed by moist inert gas oxidation rate measurements. The final series of tests will consider pure water vapor i.e., steam

Characterization of the Sublimation and Vapor Pressure of 2-(2-Nitrovinyl) Furan (G-0) Using Thermogravimetric Analysis: Effects of Complexation with Cyclodextrins.

Science.gov (United States)

Ruz, Vivian; González, Mirtha Mayra; Winant, Danny; Rodríguez, Zenaida; Van den Mooter, Guy

2015-08-19

In the present work, the sublimation of crystalline solid 2-(2-nitrovinyl) furan (G-0) in the temperature range of 35 to 60 °C (below the melting point of the drug) was studied using thermogravimetric analysis (TGA). The sublimated product was characterized using Fourier-transformed-infrared spectroscopy (FT-IR) and thin layer chromatography (TLC). The sublimation rate at each temperature was obtained using the slope of the linear regression model and followed apparent zero-order kinetics. The sublimation enthalpy from 35 to 60 °C was obtained from the Eyring equation. The Gückel method was used to estimate the sublimation rate and vapor pressure at 25 °C. Physical mixtures, kneaded and freeze-dried complexes were prepared with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) and analyzed using isothermal TGA at 50 °C. The complexation contributed to reducing the sublimation process. The best results were achieved using freeze-dried complexes with both cyclodextrins.

Characterization of Grewia Gum, a Potential Pharmaceutical Excipient

Directory of Open Access Journals (Sweden)

Elijah.I.Nep

2010-03-01

Full Text Available Grewia gum was extracted from the inner stem bark of Grewia mollis and characterized by several techniques such as gas chromatography (GC, gel permeation chromatography (GPC, scanning electron microscopy (SEM, differential scanning calorimetry (DSC and thermogravimetric analysis of the extracted sample. Spectroscopic techniques such as x-ray photoelectron spectroscopy (XPS, fourier-transformed infrared (FT-IR, solid-state nuclear magnetic resonance (NMR, and 1H and 13C NMR techniques were also used to characterize the gum. The results showed that grewia gum is a typically amorphous polysaccharide gum containing glucose, rhamnose, galactose, arabinose and xylose as neutral sugars. It has an average molecular weight of 5925 kDa expressed as the pullulan equivalent. The gum slowly hydrated in water, dispersing and swelling to form a highly viscous dispersion exhibiting pseudoplastic flow behaviour. The polysaccharide gum is thermally stable and may have application as stabilizer or suspending agent in foods, cosmetics and in pharmaceuticals. It may have application as a binder or sustained-release polymer matrix in tablets or granulations.

Rapid measurement of polychlorinated dibenzo-p-dioxins and dibenzofurans and planar chlorobiphenyls using microcolumn chromatography

Energy Technology Data Exchange (ETDEWEB)

King, T.L.; Haines, B.K.; Tokarczyk, R.; Uthe, J.F. [Department of Fisheries and Oceans, Halifax, NS (Canada). Biological Sciences Branch

1997-05-01

The concentration of polychlorinated dibenzo-p-dioxin, dibenzofuran classes and chlorobiphenyl in lobster from Atlantic Canada was measured using a newly developed quick and low-cost measuring method. The method is based on saponification followed by extraction into hexane, clean-up by gel-permeation chromatography and sulfuric acid treatment, and the separation of the non-ortho-chlorinated chlorobiphenyls and polychlorinated dibenzo-p-dioxins and dibenzofurans from other chlorinated compounds. Detection limits as low as 1-5 pg.g{sup -1} wet wt. were achieved for some of the chlorinated compounds.

Thermogravimetric research of hydrogen storage materials

International Nuclear Information System (INIS)

Kleperis, J; Grinberga, L; Ergle, M; Chikvaidze, G; Klavins, J

2007-01-01

During thermogravimetric research of metal hydrides we noticed mass growth of samples above 200 deg. C even in an argon atmosphere. Further heating is leading to the growth of weight up to 2-7 weight% till 500 0 C. Second run of the same sample without taking out of DTA instrument gave only small mass changes, indicating that noticed mass increase during first run is permanent. Microscope and elemental analyses were made to determine the reason of mass growth. XRD inspection revealed the formation of new phase with bunsenite NiO structure with deformed cubic structure. The new phase is no more active to hydrogen sorption/desorption. Our results demonstrated that the usage of hydrogen storage alloys AB 5 must be taken with care - it is important not to exceed some critical temperature were irreversible structural, compositional and morphological changes will occur

In Vitro Skin Permeation Enhancement of Sumatriptan by Microneedle Application.

Science.gov (United States)

Nalluri, Buchi N; Anusha, Sai Sri V; Bramhini, Sri R; Amulya, J; Sultana, Ashraf S K; Teja, Chandra U; Das, Diganta B

2015-01-01

Different dimensions of commercially available microneedle devices, namely, Admin- Patch(®) microneedle arrays (MN) (0.6, 0.9, 1.2 and 1.5 mm lengths) and Dermaroller(®) microneedle rollers (DR) (0.5 and 1mm lengths) were evaluated for their relative efficiency in enhancement of transdermal permeation of Sumatriptan (SMT). Solubility assessment of SMT was carried out using propylene glycol (PG), polyethylene glycol (PEG) in combination with saline (S) at different ratios and the order of solubility was found to be 70:30 > 80:20 > 90:10 %v/v in both PG:S and PEG:S. In vitro skin permeation studies were performed using PG:S (70:30 %v/v) as donor vehicle. A significant increase in cumulative amount of SMT permeated, steady state flux, permeability coefficient and diffusion coefficient values were observed after microneedle treatment, and the values were in the order of 1.5mm MN >1.2mm MN >0.9mm MN >1mm DR >0.6mm MN >0.5mm DR > passive permeation. Lag times were significantly shorter after longer microneedle application (0.24h for 1.5mm MN). Arrays were found to be superior to rollers with similar microneedle lengths in enhancing SMT permeation and may be attributed to higher density of microneedles and force of application onto skin. The in vitro flux values revealed that 2.5cm(2) area patch is sufficient for effective therapy after treatment of skin with 1.5mm MN. It may be inferred that microneedle application significantly enhances the transdermal penetration of SMT and that it may be feasible to deliver clinically relevant therapeutic levels of SMT using microneedle assisted transdermal delivery systems.

Seawater ultrafiltration fouling control: Backwashing with demineralized water/SWRO permeate

KAUST Repository

Li, Sheng; Heijman, Sebastiaan G J; Verberk, J. Q J C; Amy, Gary L.; Van Dijk, Johannis C.

2012-01-01

In this study, the effect of demineralized water backwashing on fouling control of seawater ultrafiltration was investigated. Seawater from Scheveningen beach in The Hague and a desalination plant of Evides Company at Zeeland in the Netherlands was used as feed water, while demineralized water and UF permeate were used as backwash water for a fouling control efficiency comparison under different fluxes and backwash durations. Furthermore, demineralized waters with 5 or 50 mmol/l NaCl were applied for backwashing as well, to check the influence of monovalent cations on UF fouling control. Additionally, SWRO permeate was used for backwashes in long-term experiments to check the possibility of it replacing demineralized water. Results show that seawater UF fouling control is substantially improved by demineralized water backwashing. However, due to the high salinity of seawater, more water was required to dilute the cation concentration and limit the dispersion effect near the membrane surface than was needed for surface water. A 2-min demineralized water backwash showed better fouling control efficiency than a 1-min backwash. Furthermore, the presence of monovalent cations in the backwash water deteriorated the fouling control efficiency of the backwash, indicating the existence of a charge screening effect. The demineralized water with 5 and 50 mmol/l NaCl both showed a similar fouling control efficiency which is better than the UF permeate backwash. The calcium ions in UF permeate probably deteriorates the fouling control efficiency by maintaining a Ca-bridging effect between the membranes and NOM. SWRO permeate backwashing successfully controls membrane fouling as well. © 2012 Elsevier B.V. All rights reserved.

Seawater ultrafiltration fouling control: Backwashing with demineralized water/SWRO permeate

KAUST Repository

Li, Sheng

2012-09-01

In this study, the effect of demineralized water backwashing on fouling control of seawater ultrafiltration was investigated. Seawater from Scheveningen beach in The Hague and a desalination plant of Evides Company at Zeeland in the Netherlands was used as feed water, while demineralized water and UF permeate were used as backwash water for a fouling control efficiency comparison under different fluxes and backwash durations. Furthermore, demineralized waters with 5 or 50 mmol/l NaCl were applied for backwashing as well, to check the influence of monovalent cations on UF fouling control. Additionally, SWRO permeate was used for backwashes in long-term experiments to check the possibility of it replacing demineralized water. Results show that seawater UF fouling control is substantially improved by demineralized water backwashing. However, due to the high salinity of seawater, more water was required to dilute the cation concentration and limit the dispersion effect near the membrane surface than was needed for surface water. A 2-min demineralized water backwash showed better fouling control efficiency than a 1-min backwash. Furthermore, the presence of monovalent cations in the backwash water deteriorated the fouling control efficiency of the backwash, indicating the existence of a charge screening effect. The demineralized water with 5 and 50 mmol/l NaCl both showed a similar fouling control efficiency which is better than the UF permeate backwash. The calcium ions in UF permeate probably deteriorates the fouling control efficiency by maintaining a Ca-bridging effect between the membranes and NOM. SWRO permeate backwashing successfully controls membrane fouling as well. © 2012 Elsevier B.V. All rights reserved.

Permeation of iodide from iodine-enriched yeast through porcine intestine.

Science.gov (United States)

Ryszka, Florian; Dolińska, Barbara; Zieliński, Michał; Chyra, Dagmara; Dobrzański, Zbigniew

2013-01-01

Iodine deficiency is a common phenomenon, threatening the whole global human population. Recommended daily intake of iodine is 150 μg for adults and 250 μg for pregnant and breastfeeding women. About 50% of human population can be at risk of moderate iodine deficiency. Due to this fact, increased iodine supplementation is recommended, through intake of iodized mineral water and salt iodization. The aim of this study was to investigate permeation and absorption of iodide from iodine bioplex (experimental group) in comparison with potassium iodide (controls). Permeation and absorption processes were investigated in vitro using a porcine intestine. The experimental model was based on a standard Franz diffusion cell (FD-Cell). The iodine bioplex was produced using Saccharomyces cerevisiae yeast and whey powder: iodine content - 388 μg/g, total protein - 28.5%, total fat - 0.9%., glutamic acid - 41.2%, asparaginic acid - 29.4%, lysine - 24.8%; purchased from: F.Z.N.P. Biochefa, Sosnowiec, Poland. Potassium iodide was used as controls, at 388 μg iodine concentration, which was the same as in iodine-enriched yeast bioplex. A statistically significant increase in iodide permeation was observed for iodine-enriched yeast bioplex in comparison with controls - potassium iodide. After 5h the total amount of permeated iodide from iodine-enriched yeast bioplex was 85%, which is ~ 2-fold higher than controls - 37%. Iodide absorption was by contrast statistically significantly higher in controls - 7.3%, in comparison with 4.5% in experimental group with iodine-enriched yeast bioplex. Presented results show that iodide permeation process dominates over absorption in case of iodine-enriched yeast bioplex.

In vitro permeation of platinum through African and Caucasian skin.

Science.gov (United States)

Franken, A; Eloff, F C; du Plessis, J; Badenhorst, C J; Du Plessis, J L

2015-02-03

The majority of the South African workforce are Africans, therefore potential racial differences should be considered in risk and exposure assessments in the workplace. Literature suggests African skin to be a superior barrier against permeation and irritants. Previous in vitro studies on metals only included skin from Caucasian donors, whereas this study compared the permeation of platinum through African and Caucasian skin. A donor solution of 0.3 mg/ml of potassium tetrachloroplatinate (K₂PtCl₄) dissolved in synthetic sweat was applied to the vertical Franz diffusion cells with full thickness abdominal skin. Skin from three female African and three female Caucasian donors were included (n=21). The receptor solution was removed at various intervals during the 24 h experiment, and analysed with high resolution inductively coupled plasma-mass spectrometry (ICP-MS). Skin was digested and analysed by inductively coupled plasma-optical emission spectrometry (ICP-OES). Significantly higher permeation of platinum through intact African skin (p=0.044), as well as a significantly higher mass of platinum retention in African skin in comparison with Caucasian skin (p=0.002) occurred. Significant inter-donor variation was found in both racial groups (pskin and further investigation is necessary to explain the higher permeation through African skin. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Hydrogen permeation through sol-gel-coated iron during galvanostatic charging

International Nuclear Information System (INIS)

Zakorchemna, I.; Carmona, N.; Zakroczymski, T.

2008-01-01

One-layer sol-gel silica-zirconia and two-layer silica-zirconia and zirconia coatings were deposited on one side of iron membranes by spin-coating, densified in air and annealed up to 800 deg. C in vacuum. Hydrogen permeation through the membranes, coated and uncoated, polarised cathodically under galvanostatic control in 0.1 M NaOH solution was studied using the electrochemical permeation technique. During the initial period, the effect of the sol-gel coatings was insignificant. However, the coatings quite efficiently prevented the iron surface become more active to hydrogen entry during a long-lasting cathodic polarisation. In addition, the electrochemical-corrosion behaviour of the coated iron and the effect of the sol-gel coatings on the effective diffusivity of hydrogen in the coated membranes were studied. On the basis of the polarisation curves and the hydrogen permeation data it was proved that the sol-gel coatings blocked the iron surface for the hydrogen evolution reaction and, consequently, for the hydrogen entry into iron. The effective coating coverage was determined by comparison of the hydrogen fluxes permeating the coated and uncoated membranes. Finally the real concentration of hydrogen beneath the uncoated iron sites and the amount of hydrogen stored in a membrane were evaluated

Dissolution and permeation characteristics of artemether tablets ...

African Journals Online (AJOL)

characterized by delayed drug release but enhanced permeation of the released drug. Keywords: ... and prosopis gum as binders and to consider the relationship between ..... higher tensile strength and higher brittle fracture index compared ...

Crystallization and deuterium permeation behaviors of yttrium oxide coating prepared by metal organic decomposition

Directory of Open Access Journals (Sweden)

Takumi Chikada

2016-12-01

Full Text Available Yttrium oxide coatings were fabricated on reduced activation ferritic/martensitic steels by metal organic decomposition with a dip-coating technique, and their deuterium permeation behaviors were investigated. The microstructure of the coatings varied with heat-treatment temperature: amorphous at 670ºC (amorphous coating and crystallized at 700ºC (crystallized coating. Deuterium permeation flux of the amorphous coating was lower than the uncoated steel by a factor of 5 at 500ºC, while that of the crystallized coating was lower by a factor of around 100 at 400‒550ºC. The permeation fluxes of both coatings were drastically decreased during the measurements at higher temperatures by a factor of up to 790 for the amorphous coating and 1000 for the crystallized one, indicating a microstructure modification occurred by an effect of test temperature with hydrogen flux. Temperature dependence of deuterium diffusivity in the coatings suggests that the decrease of the permeation flux has been derived from a decrease of the diffusivity. Characteristic permeation behaviors were observed with different annealing conditions; however, they can be interpreted using the permeation mechanism clarified in the previous erbium oxide coating studies.

Improved permeation barriers for tritiated waste packaging

International Nuclear Information System (INIS)

Vassallo, G.; Van Den Bergh, R.; Forcey, K.S.; Perujo, A.

1994-01-01

High-density polyethylene (HDPE) is extensively used as flexible bagging or packaging for soft tritiated waste in the tritium community because of its low permeability to the more radiotoxic form of tritium, i.e., tritiated water (HTO). However, HDPE does not represent a perfect barrier to HTO nor does it effectively hinder the permeation of elemental tritium, i.e, HT. This latter drawback is particularly important considering that the elemental form may readily convert to HTO outside of the waste package. The possible use of a multilayer film as packing material for the conditioning of tritiated waste is assessed, and its capability to hinder the permeation of elemental tritium is measured and compared with that of bare HDPE. The material investigated is readily available from the food industry. 5 refs., 1 tab

Heater-Integrated Cantilevers for Nano-Samples Thermogravimetric Analysis

Directory of Open Access Journals (Sweden)

Valeria Toffoli

2013-12-01

Full Text Available The design and characteristics of a micro-system for thermogravimetric analysis (TGA in which heater, temperature sensor and mass sensor are integrated into a single device are presented. The system consists of a suspended cantilever that incorporates a microfabricated resistor, used as both heater and thermometer. A three-dimensional finite element analysis was used to define the structure parameters. TGA sensors were fabricated by standard microlithographic techniques and tested using milli-Q water and polyurethane microcapsule. The results demonstrated that our approach provides a faster and more sensitive TGA with respect to commercial systems.

Differential permeation of piroxicam-loaded PLGA micro/nanoparticles and their in vitro enhancement

International Nuclear Information System (INIS)

Shankarayan, Raju; Kumar, Sumit; Mishra, Prashant

2013-01-01

Piroxicam is a non-steroidal anti-inflammatory drug used for the treatment of musculoskeletal pain. The main problem encountered when piroxicam is administered orally is its gastric side-effect (ulcer, bleeding and holes in the stomach). Transmucosal delivery and encapsulation of piroxicam in biodegradable particles offer potential advantages over conventional oral delivery. The present study was aimed to develop an alternative to piroxicam-delivery which could overcome the direct contact of the drug at the mucosal membrane and its permeation through the mucosal membrane was studied. To achieve this, the piroxicam was encapsulated in Poly (lactide-co-glycolide) (PLGA) microparticles (size 1–4 μm, encapsulation efficiency 80–85 %) and nanoparticles (size 151.6 ± 28.6 nm, encapsulation efficiency 92.17 ± 3.08 %). Various formulation process parameters were optimised for the preparation of piroxicam-loaded PLGA nanoparticles of optimal size and encapsulation efficiency. Transmucosal permeability of piroxicam-loaded PLGA micro- and nanoparticles through the porcine oesophageal mucosa was studied. Using fluorescently labelled PLGA micro- and nanoparticles, size-dependent permeation was demonstrated. Furthermore, the effect of different permeation enhancers on the flux rate and permeability coefficient for the permeation of nanoparticles was investigated. The results suggested that amongst the permeation enhancers used the most efficient enhancement of permeation was observed with 10 mM sodium dodecyl sulphate.

Differential permeation of piroxicam-loaded PLGA micro/nanoparticles and their in vitro enhancement

Energy Technology Data Exchange (ETDEWEB)

Shankarayan, Raju; Kumar, Sumit; Mishra, Prashant, E-mail: pmishra@dbeb.iitd.ac.in [Indian Institute of Technology Delhi, Department of Biochemical Engineering and Biotechnology (India)

2013-03-15

Piroxicam is a non-steroidal anti-inflammatory drug used for the treatment of musculoskeletal pain. The main problem encountered when piroxicam is administered orally is its gastric side-effect (ulcer, bleeding and holes in the stomach). Transmucosal delivery and encapsulation of piroxicam in biodegradable particles offer potential advantages over conventional oral delivery. The present study was aimed to develop an alternative to piroxicam-delivery which could overcome the direct contact of the drug at the mucosal membrane and its permeation through the mucosal membrane was studied. To achieve this, the piroxicam was encapsulated in Poly (lactide-co-glycolide) (PLGA) microparticles (size 1-4 {mu}m, encapsulation efficiency 80-85 %) and nanoparticles (size 151.6 {+-} 28.6 nm, encapsulation efficiency 92.17 {+-} 3.08 %). Various formulation process parameters were optimised for the preparation of piroxicam-loaded PLGA nanoparticles of optimal size and encapsulation efficiency. Transmucosal permeability of piroxicam-loaded PLGA micro- and nanoparticles through the porcine oesophageal mucosa was studied. Using fluorescently labelled PLGA micro- and nanoparticles, size-dependent permeation was demonstrated. Furthermore, the effect of different permeation enhancers on the flux rate and permeability coefficient for the permeation of nanoparticles was investigated. The results suggested that amongst the permeation enhancers used the most efficient enhancement of permeation was observed with 10 mM sodium dodecyl sulphate.

Differential permeation of piroxicam-loaded PLGA micro/nanoparticles and their in vitro enhancement

Science.gov (United States)

Shankarayan, Raju; Kumar, Sumit; Mishra, Prashant

2013-03-01

Piroxicam is a non-steroidal anti-inflammatory drug used for the treatment of musculoskeletal pain. The main problem encountered when piroxicam is administered orally is its gastric side-effect (ulcer, bleeding and holes in the stomach). Transmucosal delivery and encapsulation of piroxicam in biodegradable particles offer potential advantages over conventional oral delivery. The present study was aimed to develop an alternative to piroxicam-delivery which could overcome the direct contact of the drug at the mucosal membrane and its permeation through the mucosal membrane was studied. To achieve this, the piroxicam was encapsulated in Poly (lactide- co-glycolide) (PLGA) microparticles (size 1-4 μm, encapsulation efficiency 80-85 %) and nanoparticles (size 151.6 ± 28.6 nm, encapsulation efficiency 92.17 ± 3.08 %). Various formulation process parameters were optimised for the preparation of piroxicam-loaded PLGA nanoparticles of optimal size and encapsulation efficiency. Transmucosal permeability of piroxicam-loaded PLGA micro- and nanoparticles through the porcine oesophageal mucosa was studied. Using fluorescently labelled PLGA micro- and nanoparticles, size-dependent permeation was demonstrated. Furthermore, the effect of different permeation enhancers on the flux rate and permeability coefficient for the permeation of nanoparticles was investigated. The results suggested that amongst the permeation enhancers used the most efficient enhancement of permeation was observed with 10 mM sodium dodecyl sulphate.

Chromatic response of polydiacetylene vesicle induced by the permeation of methotrexate.

Science.gov (United States)

Shin, Min Jae; Kim, Ye Jin; Kim, Jong-Duk

2015-07-07

The noble vesicular system of polydiacetylene showed a red shift using two types of detecting systems. One of the systems involves the absorption of target materials from the outer side of the vesicle, and the other system involves the permeation through the vesicular layers from within the vesicle. The chromatic mixed vesicles of N-(2-aminoethyl)pentacosa-10,12-diynamide (AEPCDA) and dimethyldioctadecylammonium chloride (DODAC) were fabricated by sonication, followed by polymerization by UV irradiation. The stability of monomeric vesicles was observed to increase with the polymerization of the vesicles. Methotrexate was used as a target material. The polymerized mixed vesicles having a blue color were exposed to a concentration gradient of methotrexate, and a red shift was observed indicating the adsorption of methotrexate on the polydiacetylene bilayer. In order to check the chromatic change by the permeation of methotrexate, we separated the vesicle portion, which contained methotrexate inside the vesicle, and checked chromatic change during the permeation of methotrexate through the vesicle. The red shift apparently indicates the disturbance in the bilayer induced by the permeation of methotrexate. The maximum contrast of color appeared at the equal molar ratio of AEPCDA and DODAC, indicating that the formation of flexible and deformable vesicular layers is important for red shift. Therefore, it is hypothesized that the system can be applicable for the chromatic detection of the permeation of methotrexate through the polydiacetylene layer.

Financial Permeation and Economic Growth: Evidence from Sub-Saharan Africa

OpenAIRE

Inoue, Takeshi; Hamori, Shigeyuki

2013-01-01

This article empirically analyzes the role of finance in economic growth in Sub-Saharan Africa from the perspective of what is termed herein “financial permeation”. By estimating panel data on 37 countries in Sub-Saharan Africa between 2004 and 2010, we examine whether financial permeation through improved convenience and access to financial services has contributed to economic growth in this region. Empirical results clearly indicate that financial permeation has a statistically significant ...

Measurement of tritium permeation through resistant materials near room temperature

International Nuclear Information System (INIS)

Maienschein, J.; DuVal, V.; McMurphy, F.; Uribe, F.; Musket, R.; Brown, D.

1985-01-01

To measure tritium permeation through low-permeability materials at 50 to 170 0 C, we use highly-sensitive liquid scintillation counting to detect the permeating tritium. To validate our method, we conducted extensive experiments with copper, for which much data exists for comparison. We report permeability of tritium through copper at 50, 100, and 170 0 C, and discuss details of the experimental technique. Further plans are outlined. 15 refs., 5 figs., 1 tab

Curie temperature determination via thermogravimetric and continuous wavelet transformation analysis

Energy Technology Data Exchange (ETDEWEB)

Hasier, John; Nash, Philip [Thermal Processing Technology Center, IIT, Chicago, IL (United States); Riolo, Maria Annichia [University of Michigan, Center for the Study of Complex Systems, Ann Arbor, MI (United States)

2017-12-15

A cost effective method for conversion of a vertical tube thermogravimetric analysis system into a magnetic balance capable of measuring Curie Temperatures is presented. Reference and preliminary experimental data generated using this system is analyzed via a general-purpose wavelet based Curie point edge detection technique allowing for enhanced speed, ease and repeatability of magnetic balance data analysis. The Curie temperatures for a number of Heusler compounds are reported. (orig.)

Rationalizing the permeation of polar antibiotics into Gram-negative bacteria

International Nuclear Information System (INIS)

Scorciapino, Mariano Andrea; Acosta-Gutierrez, Silvia; Benkerrou, Dehbia; D’Agostino, Tommaso; Malloci, Giuliano; Samanta, Susruta; Bodrenko, Igor; Ceccarelli, Matteo

2017-01-01

The increasing level of antibiotic resistance in Gram-negative bacteria, together with the lack of new potential drug scaffolds in the pipeline, make the problem of infectious diseases a global challenge for modern medicine. The main reason that Gram-negative bacteria are particularly challenging is the presence of an outer cell-protecting membrane, which is not present in Gram-positive species. Such an asymmetric bilayer is a highly effective barrier for polar molecules. Several protein systems are expressed in the outer membrane to control the internal concentration of both nutrients and noxious species, in particular: (i) water-filled channels that modulate the permeation of polar molecules and ions according to concentration gradients, and (ii) efflux pumps to actively expel toxic compounds. Thus, besides expressing specific enzymes for drugs degradation, Gram-negative bacteria can also resist by modulating the influx and efflux of antibiotics, keeping the internal concentration low. However, there are no direct and robust experimental methods capable of measuring the permeability of small molecules, thus severely limiting our knowledge of the molecular mechanisms that ultimately control the permeation of antibiotics through the outer membrane. This is the innovation gap to be filled for Gram-negative bacteria. This review is focused on the permeation of small molecules through porins, considered the main path for the entry of polar antibiotics into Gram-negative bacteria. A fundamental understanding of how these proteins are able to filter small molecules is a prerequisite to design/optimize antibacterials with improved permeation. The level of sophistication of modern molecular modeling algorithms and the advances in new computer hardware has made the simulation of such complex processes possible at the molecular level. In this work we aim to share our experience and perspectives in the context of a multidisciplinary extended collaboration within the IMI

Rationalizing the permeation of polar antibiotics into Gram-negative bacteria

Science.gov (United States)

Scorciapino, Mariano Andrea; Acosta-Gutierrez, Silvia; Benkerrou, Dehbia; D'Agostino, Tommaso; Malloci, Giuliano; Samanta, Susruta; Bodrenko, Igor; Ceccarelli, Matteo

2017-03-01

The increasing level of antibiotic resistance in Gram-negative bacteria, together with the lack of new potential drug scaffolds in the pipeline, make the problem of infectious diseases a global challenge for modern medicine. The main reason that Gram-negative bacteria are particularly challenging is the presence of an outer cell-protecting membrane, which is not present in Gram-positive species. Such an asymmetric bilayer is a highly effective barrier for polar molecules. Several protein systems are expressed in the outer membrane to control the internal concentration of both nutrients and noxious species, in particular: (i) water-filled channels that modulate the permeation of polar molecules and ions according to concentration gradients, and (ii) efflux pumps to actively expel toxic compounds. Thus, besides expressing specific enzymes for drugs degradation, Gram-negative bacteria can also resist by modulating the influx and efflux of antibiotics, keeping the internal concentration low. However, there are no direct and robust experimental methods capable of measuring the permeability of small molecules, thus severely limiting our knowledge of the molecular mechanisms that ultimately control the permeation of antibiotics through the outer membrane. This is the innovation gap to be filled for Gram-negative bacteria. This review is focused on the permeation of small molecules through porins, considered the main path for the entry of polar antibiotics into Gram-negative bacteria. A fundamental understanding of how these proteins are able to filter small molecules is a prerequisite to design/optimize antibacterials with improved permeation. The level of sophistication of modern molecular modeling algorithms and the advances in new computer hardware has made the simulation of such complex processes possible at the molecular level. In this work we aim to share our experience and perspectives in the context of a multidisciplinary extended collaboration within the IMI

Changes in chemical permeation of disposable latex, nitrile, and vinyl gloves exposed to simulated movement.

Science.gov (United States)

Phalen, Robert N; Le, Thi; Wong, Weng Kee

2014-01-01

Glove movement can affect chemical permeation of organic compounds through polymer glove products. However, conflicting reports make it difficult to compare the effects of movement on chemical permeation through commonly available glove types. The aim of this study was to evaluate the effect of movement on chemical permeation of an organic solvent through disposable latex, nitrile, and vinyl gloves. Simulated whole-glove permeation testing was conducted using ethyl alcohol and a previously designed permeation test system. With exposure to movement, a significant decrease (p ≤ 0.001) in breakthrough time (BT) was observed for the latex (-23%) and nitrile gloves (-31%). With exposure to movement, only the nitrile glove exhibited a significant increase (p ≤ 0.001) in steady-state permeation rate (+47%) and cumulative permeation at 30 min (+111%). Even though the nitrile glove provided optimum chemical resistance against ethyl alcohol, it was most affected by movement. With exposure to movement, the latex glove was an equivalent option for overall worker protection, because it was less affected by movement and the permeation rate was lower than that of the nitrile glove. In contrast, the vinyl glove was the least affected by movement, but did not provide adequate chemical resistance to ethyl alcohol in comparison with the nitrile and latex gloves. Glove selection should take movement and polymer type into account. Some glove polymer types are less affected by movement, most notably the latex glove in this test. With nitrile gloves, at least a factor of three should be used when attempting to assign a protection factor when repetitive hand motions are anticipated. Ultimately, the latex gloves outperformed nitrile and vinyl in these tests, which evaluated the effect of movement on chemical permeation. Future research should aim to resolve some of the observed discrepancies in test results with latex and vinyl gloves.

Modeling the Effects of Interfacial Characteristics on Gas Permeation Behavior of Nanotube-Mixed Matrix Membranes.

Science.gov (United States)

Chehrazi, Ehsan; Sharif, Alireza; Omidkhah, Mohammadreza; Karimi, Mohammad

2017-10-25

Theoretical approaches that accurately predict the gas permeation behavior of nanotube-containing mixed matrix membranes (nanotube-MMMs) are scarce. This is mainly due to ignoring the effects of nanotube/matrix interfacial characteristics in the existing theories. In this paper, based on the analogy of thermal conduction in polymer composites containing nanotubes, we develop a model to describe gas permeation through nanotube-MMMs. Two new parameters, "interfacial thickness" (a int ) and "interfacial permeation resistance" (R int ), are introduced to account for the role of nanotube/matrix interfacial interactions in the proposed model. The obtained values of a int , independent of the nature of the permeate gas, increased by increasing both the nanotubes aspect ratio and polymer-nanotube interfacial strength. An excellent correlation between the values of a int and polymer-nanotube interaction parameters, χ, helped to accurately reproduce the existing experimental data from the literature without the need to resort to any adjustable parameter. The data includes 10 sets of CO 2 /CH 4 permeation, 12 sets of CO 2 /N 2 permeation, 3 sets of CO 2 /O 2 permeation, and 2 sets of CO 2 /H 2 permeation through different nanotube-MMMs. Moreover, the average absolute relative errors between the experimental data and the predicted values of the proposed model are very small (less than 5%) in comparison with those of the existing models in the literature. To the best of our knowledge, this is the first study where such a systematic comparison between model predictions and such extensive experimental data is presented. Finally, the new way of assessing gas permeation data presented in the current work would be a simple alternative to complex approaches that are usually utilized to estimate interfacial thickness in polymer composites.

Double electrolyte sensor for monitoring hydrogen permeation rate in steels

International Nuclear Information System (INIS)

Ouyang, Y.J.; Yu, G.; Ou, A.L.; Hu, L.; Xu, W.J.

2011-01-01

Highlights: → Designed an amperometric hydrogen sensor with double electrolytes. → Explained the principle of determining hydrogen permeation rate. → Verified good stability, reproducibility and correctness of the developed sensor. → Field on-line monitoring the susceptivity of hydrogen induced cracks. - Abstract: An amperometric hydrogen sensor with double electrolytes composed of a gelatiniform electrolyte and KOH solution has been developed to determine the permeation rate of hydrogen atoms in steel equipment owing to hydrogen corrosion. The gelatiniform electrolyte was made of sodium polyacrylate (PAAS), carboxyl methyl cellulose (CMC) and 0.2 mol dm -3 KOH solution. The results show that the gelatiniform electrolyte containing 50 wt.% polymers has suitable viscosity and high electrical conductivity. The consistent permeation curves were detected by the sensor of the double electrolyte and single liquid KOH electrolyte, respectively. The developed sensor has good stability and reproducibility at room temperature.

Double electrolyte sensor for monitoring hydrogen permeation rate in steels

Energy Technology Data Exchange (ETDEWEB)

Ouyang, Y.J. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Department of Chemistry and Chemical Engineering, Huaihua College, Huaihua 418008 (China); Yu, G., E-mail: yuganghnu@163.co [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Ou, A.L.; Hu, L.; Xu, W.J. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

2011-06-15

Highlights: {yields} Designed an amperometric hydrogen sensor with double electrolytes. {yields} Explained the principle of determining hydrogen permeation rate. {yields} Verified good stability, reproducibility and correctness of the developed sensor. {yields} Field on-line monitoring the susceptivity of hydrogen induced cracks. - Abstract: An amperometric hydrogen sensor with double electrolytes composed of a gelatiniform electrolyte and KOH solution has been developed to determine the permeation rate of hydrogen atoms in steel equipment owing to hydrogen corrosion. The gelatiniform electrolyte was made of sodium polyacrylate (PAAS), carboxyl methyl cellulose (CMC) and 0.2 mol dm{sup -3} KOH solution. The results show that the gelatiniform electrolyte containing 50 wt.% polymers has suitable viscosity and high electrical conductivity. The consistent permeation curves were detected by the sensor of the double electrolyte and single liquid KOH electrolyte, respectively. The developed sensor has good stability and reproducibility at room temperature.

Thermogravimetric-Mass Spectrometric Study of the Pyrolysis Behavior of PVC

Institute of Scientific and Technical Information of China (English)

SUN Qing-lei; SHI Xin-gang; LIN Yun-liang; ZHU He; WANG Xiao; CHENG Chuan-ge; LIU Jian-hua

2007-01-01

The pyrolysis characteristics of PVC were systematically investigated using a Netzschne TG thermo-balance coupled to a quadrupole mass spectrometer. The pyrolysis conditions were 0.1 MPa of Ar, a heating rate of 10 ℃/min and a final temperature of 1000 ℃. Both the thermogravimetric properties and the simultaneous evolution of gaseous products during pyrolysis were studied. The TG/DTG results showed that as the pyrolysis temperature increases the weight loss and weight loss rate of PVC increases. Near 412 ℃ the weight loss rate attained its peak value. At higher temperatures the rate of loss gradually decreases. The gases evolved during thermogravimetric analysis were analyzed by a mass spectrometer, monitoring the relative intensity of HCl, C6H6, light hydrocarbon and chlorine-containing gases. The evolution curves showed that HCl, C6H6, light hydrocarbon and chlorine-containing gases all peak at about 416 ℃. This is consistent with the fact that the weight loss curves also peak at about 412 ℃. The extensive HCl evolution is consistent with the high chlorine content of PVC. The formation of these gases can be explained by considering these reactions: dehydrochlorination, intramolecular cyclization and the addition of HCl to unsaturated hydrocarbons.

Thermogravimetric measurements of liquid vapor pressure

International Nuclear Information System (INIS)

Rong Yunhong; Gregson, Christopher M.; Parker, Alan

2012-01-01

Highlights: ► Rapid determination of vapor pressure by TGA. ► Demonstration of limitations of currently available approaches in literature. ► New model for vapor pressure assessment of small size samples in TGA. ► New model accounts for vapor diffusion and sample geometry and measures vapor pressure normally within 10%. - Abstract: A method was developed using thermo-gravimetric analysis (TGA) to determine the vapor pressure of volatile liquids. This is achieved by measuring the rate of evaporation (mass loss) of a pure liquid contained within a cylindrical pan. The influence of factors like sample geometry and vapor diffusion on evaporation rate are discussed. The measurement can be performed across a wide range of temperature yielding reasonable results up to 10 kPa. This approach may be useful as a rapid and automatable method for measuring the volatility of flavor and fragrance raw materials.

Thermogravimetric analysis and thermal degradation behaviour of advanced PMR-X carbon fiber composites

International Nuclear Information System (INIS)

Rngie, M.

2003-01-01

Thermal degradation behavior of sized and unsized carbon fibers in polyimide matrix was investigated. Degradation of neat resin and unidirectional laminates were investigated by thermogravimetric analysis technique at temperatures between 470 d ig C -650 d ig C and up to 250 h rs. Isothermal ageing of the PMR-X composite samples under different test conditions (i. e. different temperatures and prolonged aging times), showed that oxidation and degradation occurs in stage three different rates. Thermogravimetric analysis showed that the cured PMR-X composite panels are more stable in an inert atmosphere (nitrogen atmosphere)than in air and the degradation of neat resin is much higher than the composite samples. However, the rate of degradation of the unsized untreated carbon fibers in nitrogen environment is much higher than that for the PMR-X composites containing sized fibers

Gas permeation process for post combustion CO2 capture

International Nuclear Information System (INIS)

Pfister, Marc

2017-01-01

CO 2 Capture and Storage (CCS) is a promising solution to separate CO 2 from flue gas, to reduce the CO 2 emissions in the atmosphere, and hence to reduce global warming. In CCS, one important constraint is the high additional energy requirement of the different capture processes. That statement is partly explained by the low CO 2 fraction in the inlet flue gas and the high output targets in terms of CO 2 capture and purity (≥90%). Gas permeation across dense membrane can be used in post combustion CO 2 capture. Gas permeation in a dense membrane is ruled by a mass transfer mechanism and separation performance in a dense membrane are characterized by component's effective permeability and selectivity. One of the newest and encouraging type of membrane in terms of separation performance is the facilitated transport membrane. Each particular type of membrane is defined by a specific mass transfer law. The most important difference to the mass transfer behavior in a dense membrane is related to the facilitated transport mechanism and the solution diffusion mechanism and its restrictions and limitations. Permeation flux modelling across a dense membrane is required to perform a post combustion CO 2 capture process simulation. A CO 2 gas permeation separation process is composed of a two-steps membrane process, one drying step and a compression unit. Simulation on the energy requirement and surface area of the different membrane modules in the global system are useful to determine the benefits of using dense membranes in a post combustion CO 2 capture technology. (author)

In vitro permeation studies of nanoemulsions containing ketoprofen as a model drug.

Science.gov (United States)

Kim, Beom Su; Won, Myoung; Lee, Kang Min; Kim, Cheo Sang

2008-09-01

We prepared a nanoemulsion system with benzyl alcohol/ ethanol/Solutol/smash(R) HS 15 /water. Ketoprofen was used as a model drug in this study. The nanoemulsions of this system evidenced a high degree of stability. The droplet diameter did not change over a period of at least 3 months. The nanoemulsion containing 4% benzyl alcohol evidenced a permeation rate higher than was observed with the 1% and 2% nanoemulsions. Also the nanoemulsion containing 1% Solutol(R) HS 15 provided a permeation rate higher than was seen with the 2% and 4% nanoemulsions. All ketoprofen-loaded nanoemulsions enhanced the in vitro permeation rate through mouse skins as compared to the control.

Influence of nitrogen ion implantation on hydrogen permeation in an extra mild steel

International Nuclear Information System (INIS)

Brass, A.M.; Chene, J.; Pivin, J.C.

1989-01-01

This paper presents the first results on the effect of nitrogen implantation on hydrogen permeation in steels. Nitrogen can modify superficially the steel's chemistry and/or microstructure depending on the fluence and thereby affect the processes of hydrogen diffusion and trapping. The implantations were performed on low carbon steel specimens with different nominal doses (1% to 10% and 33% nitrogen in a superficial layer of approximately 100 to 120 nm). The corresponding microstructures were characterized and permeation tests were conducted at room temperature in a double electrolytic cell. The nitrogen implanted layers on iron affects the electrochemical behaviour of the surface and the permeation in the material. This effect depends on the nitrogen concentration in the layer and on the corresponding microstructure. A continuous Fe 2 N layer acts as an efficient barrier to hydrogen entry and permeation when the layer is located on the entry face of the permeation membrane. This effect is stronger when the implanted layer is on the downstream face of the membrane. The low permeability values are mainly attributed to a lower hydrogen solubility in the implanted layer, whereas hydrogen trapping on defects and nitride precipitates delay hydrogen penetration. (author)

40 CFR 90.129 - Fuel tank permeation from handheld engines and equipment.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Fuel tank permeation from handheld... KILOWATTS Emission Standards and Certification Provisions § 90.129 Fuel tank permeation from handheld... equipment with respect to fuel tanks. For the purposes of this section, fuel tanks do not include fuel caps...

Ion-driven permeation of deuterium through tungsten under simultaneous helium and deuterium irradiation

International Nuclear Information System (INIS)

Lee, H.T.; Tanaka, H.; Ohtsuka, Y.; Ueda, Y.

2011-01-01

Ion-driven permeation of D through tungsten under simultaneous irradiation with He-D was measured as a function of temperature, flux, and energy. He reduced the permeation flux with the reduction increasing with decreasing temperature. The reduction in permeation flux followed a linear dependence to the incident flux at T > 1000 K, but shifted to a square root dependence at T < 1000 K. The results were interpreted as shifts from diffusion limited to recombination limited H transport according to Doyle and Brice's theory. Arrhenius functions of front diffusivity and recombination coefficients were derived and used to calculate the transport parameter W. The effect of He can be interpreted as changes to the front diffusivity that approaches H diffusion behavior in the absence of traps. The reduction in total concentration results in a shallower concentration gradient that can describe the observed decrease in permeation.

Hydrogen and deuterium permeation in copper alloys, copper--gold brazing alloys, gold, and the in situ growth of stable oxide permeation barriers

International Nuclear Information System (INIS)

Begeal, D.R.

1978-01-01

The deuterium permeation through several copper alloys has been measured over a temperature range of 550 to 830 K using the membrane technique. In some cases, the hydrogen permeability was also measured. The results were divided into three categories: common alloys, gold alloys, and stable oxide forming alloys. Common alloys which showed typical bulk metallic diffusion with litle change in the permeation activation energy as compared to copper (77 kJ/mol for D 2 ) were: (additions are in weight percent) 5% Sn, 2.3% U, 0.15% Zr, 4% Sn+4% Pb+4% Zn, 3% Si, and 7% Al+2% Fe. Compared to copper, the D 2 permeability at 573 K was reduced by factors of 2.0, 2.7, 4.5, 5.3, 5.9, and 7.0, respectively. A series of gold--copper alloys including pure gold, 80% Au, 50% Au, 49% Au, and 35% Au also showed typical bulk metallic diffusion with a trend of decreasing permeability (increasing activation energies for permeation) with increasing gold content. There were also pronounced inflections or shifts in the permeability at approx.370 0 C, or about the order--disorder transition for Cu 3 Au and CuAu, for the 80% and 50% alloys. Two alloys did not exhibit bulk metallic permeation behavior and the permeabiltiy was in fact controlled by surface oxide layers. It was found that a layer of beryllium oxide could be formed on Cu+2% Be and a layer of aluminum oxide could be formed on Cu+7% Al+2% Si. As compared to 0.25 mm-thick copper, the deuterium permeability at 500 0 C was reduced by a factor of approx.250 for Cu--Be and approx.1000 for Cu--Al--Si. The activation energies for deuterium permeation were 98 kJ/mol and 132 kJ/mol, respectively. The mechanism for the oxide growth is the high-temperature hydrogen reduction of nearby less stable oxides, simultaneous with oxidation of the active metal, Be or Al, by trace amounts of water in the hydrogen. Ion microprobe mass analysis identified the oxide layers as containing beryllium or aluminum but not containing copper

Hydrogen permeation behavior through F82H at high temperature

Energy Technology Data Exchange (ETDEWEB)

Matsuda, S.; Katayama, K.; Shimozori, M.; Fukada, S. [Interdisciplinary Graduate School of Engineering Science, Kyushu University, Kyushu (Japan); Ushida, H. [Energy Science and Engineering, Faculty of Engineering, Kyushu University, Kyushu (Japan); Nishikawa, M. [Malaysia-Japan International Institute of Technology, UTM, Kuala Lumpur (Malaysia)

2015-03-15

F82H is a primary candidate of structural material and coolant pipe material in a blanket of a fusion reactor. Understanding tritium permeation behavior through F82H is important. In a normal operation of a fusion reactor, the temperature of F82H will be controlled below 550 C. degrees because it is considered that F82H can be used up to 30,000 hours at 550 C. degrees. However, it is necessary to assume the situation where F82H is heated over 550 C. degrees in a severe accident. In this study, hydrogen permeation behavior through F82H was investigated in the temperature range from 500 to 800 C. degrees. In some cases, water vapor was added in a sample gas to investigate an effect of water vapor on hydrogen permeation. The permeability of hydrogen in the temperature range from 500 to 700 C. degrees agreed well with the permeability reported by E. Serra et al. The degradation of the permeability by water vapor was not observed. After the hydrogen permeation reached in a steady state at 700 C. degrees, the F82H sample was heated to 800 C. degrees. The permeability of hydrogen through F82H sample which was once heated up to 800 C. degrees was lower than that of the original one. (authors)

Dual-directional regulation of drug permeating amount by combining the technique of ion-pair complexation with chemical enhancers for the synchronous permeation of indapamide and bisoprolol in their compound patch through rabbit skin.

Science.gov (United States)

Song, Wenting; Cun, Dongmei; Quan, Peng; Liu, Nannan; Chen, Yang; Cui, Hongxia; Xiang, Rongwu; Fang, Liang

2015-04-01

To achieve the synchronous skin permeation of indapamide (IND) and bisoprolol (BSP) in their compound patch, the techniques of ion-pair complexation and chemical enhancers were combined to dual-directionally regulate drug permeating amounts. Ion-pair complexes of BSP and various organic acids were formed by the technique of ion-pair complexation. Among the complexes formed, bisoprolol tartrate (BSP.T) down-regulated the permeating amount of BSP to the same extent as that of IND. Then, to simultaneously up-regulate the amounts of the two drugs, an enhancer combination of 15.8% Span80 (SP), 6.0% Azone (AZ) and 2.2% N-methyl pyrrolidone (NMP) was obtained by central composite design and exhibited an outstanding and simultaneous enhancement on IND and BSP with enhancing ratio (ER) of 4.52 and 3.49, respectively. The effect of the dual-directional regulation was evaluated by in vitro permeation experiments and in vivo pharmacokinetic studies. For IND and BSP, their observed permeation profiles were comparable and their MAT (mean absorption time) showed no significant difference, which both demonstrated these two drugs achieved the synchronous skin permeation in their compound patch by the dual-directional regulation strategy of combining the technique of ion-pair complexation with chemical enhancers. Copyright © 2015 Elsevier B.V. All rights reserved.

Oxygen permeation and thermo-chemical stability of oxygen separation membrane materials for the oxyfuel process

Energy Technology Data Exchange (ETDEWEB)

Ellett, Anna Judith

2009-07-01

The reduction of CO{sub 2} emissions, generally held to be one of the most significant contributors to global warming, is a major technological issue. CO{sub 2} Capture and Storage (CCS) techniques applied to large stationary sources such as coal-fired power plants could efficiently contribute to the global carbon mitigation effort. The oxyfuel process, which consists in the burning of coal in an oxygen-rich atmosphere to produce a flue gas highly concentrated in CO{sub 2}, is a technology considered for zero CO{sub 2} emission coal-fired power plants. The production of this O{sub 2}-rich combustion gas from air can be carried out using high purity oxygen separation membranes. Some of the most promising materials for this application are mixed ionic-electronic conducting (MIEC) materials with perovskite and K{sub 2}NiF{sub 4} perovskite-related structures. The present work examines the selection of La{sub 0.58}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCF58), La{sub 2}NiO{sub 4+{delta}}, Pr{sub 0.58}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (PSCF58) and Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (BSCF50) as membrane materials for the separation of O{sub 2} and N{sub 2} in the framework of the oxyfuel process with flue gas recycling. Annealing experiments were carried out on pellets exposed to CO{sub 2}, water vapour, O{sub 2} and Cr{sub 2}O{sub 3} in order to determine the thermo-chemical resistance to the atmospheres and the high temperature conditions present during membrane operation in a coal-fired power plant. The degradation of their microstructure was investigated using Scanning Electron Microscopy (SEM) in combination with electron dispersive spectroscopy (EDS) as well as X-Ray Diffraction (XRD). Also, the oxygen permeation fluxes of selected membranes were investigated as a function of temperature. The membrane materials selected were characterised using thermo-analytical techniques such as precision thermogravimetric

Thermogravimetric analysis-mass spectrometry (TG-MS) of selected Chinese palygorskites-Implications for structural water

International Nuclear Information System (INIS)

Cheng, Hongfei; Yang, Jing; Frost, Ray L.

2011-01-01

Four Chinese palygorskites clay minerals have been analysed by thermogravimetric analysis-mass spectrometry and X-ray diffraction. The structural water of the palygorskite dehydrates in the temperature range of 30-625 o C, as shown in the thermogravimetric analysis and mass spectrometric curves. The mass spectrometric curves combined the differential thermogravimetric curves enable the detailed determination of the main dehydration steps. The results show that the dehydration occurs in four main steps: (a) elimination of interparticle water and partial zeolitic water at below 110 o C, (b) release of the rest part of zeolitic water from the structural layer of palygorskite at about 160 o C, (c) dehydration of one part of bound water at about 340 o C and (d) loss of the rest part of bound water at around 450 o C. The temperatures of dehydration of the palygorskite minerals are found to be influenced by the geological environment and the amount and kind of impurities. The evolved gases in the decomposition process are various because of the different amounts and kind of impurities. It is also found that decarbonization takes place at around 600 o C due to the decomposition of calcite and dolomite impurities in these minerals. It is evident by the mass spectrometric curve that the water is given out from the samples and carbon dioxide originates from the impurity calcite and dolomite.

Human skin in vitro permeation of bentazon and isoproturon formulations with or without protective clothing suit.

Science.gov (United States)

Berthet, Aurélie; Hopf, Nancy B; Miles, Alexandra; Spring, Philipp; Charrière, Nicole; Garrigou, Alain; Baldi, Isabelle; Vernez, David

2014-01-01

Skin exposures to chemicals may lead, through percutaneous permeation, to a significant increase in systemic circulation. Skin is the primary route of entry during some occupational activities, especially in agriculture. To reduce skin exposures, the use of personal protective equipment (PPE) is recommended. PPE efficiency is characterized as the time until products permeate through material (lag time, Tlag). Both skin and PPE permeations are assessed using similar in vitro methods; the diffusion cell system. Flow-through diffusion cells were used in this study to assess the permeation of two herbicides, bentazon and isoproturon, as well as four related commercial formulations (Basagran(®), Basamais(®), Arelon(®) and Matara(®)). Permeation was measured through fresh excised human skin, protective clothing suits (suits) (Microchem(®) 3000, AgriSafe Pro(®), Proshield(®) and Microgard(®) 2000 Plus Green), and a combination of skin and suits. Both herbicides, tested by itself or as an active ingredient in formulations, permeated readily through human skin and tested suits (Tlag < 2 h). High permeation coefficients were obtained regardless of formulations or tested membranes, except for Microchem(®) 3000. Short Tlag, were observed even when skin was covered with suits, except for Microchem(®) 3000. Kp values tended to decrease when suits covered the skin (except when Arelon(®) was applied to skin covered with AgriSafe Pro and Microgard(®) 2000), suggesting that Tlag alone is insufficient in characterizing suits. To better estimate human skin permeations, in vitro experiments should not only use human skin but also consider the intended use of the suit, i.e., the active ingredient concentrations and type of formulations, which significantly affect skin permeation.

Deuterium permeation of amorphous alumina coating on 316L prepared by MOCVD

International Nuclear Information System (INIS)

Li Shuai; He Di; Liu Xiaopeng; Wang Shumao; Jiang Lijun

2012-01-01

Highlights: ► Deuterium permeation behavior of alumina coating by MOCVD is investigated. ► The as-prepared alumina is amorphous. ► The alumina coating is dense and well adherent to substrate. ► Deuterium permeation rate of alumina coating is 2–3 orders of magnitude lower than martensitic steels. - Abstract: The deuterium permeation behavior of the alumina coating on 316L stainless steel prepared by metal organic chemical vapor deposition (MOCVD) was investigated. The alumina coating was also characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). It was found that the as-prepared coating consisted of amorphous alumina. This alumina coating had a dense, crack-free and homogeneous morphology. Although the alumina coating was amorphous, effective suppression of deuterium permeation was demonstrated. The deuterium permeability of the alumina coating was 51–60 times less than that of the 316L stainless steel and 153–335 times less than that of the referred low activation martensitic steels at 860–960 K.

Tritium permeation barriers in contact with liquid lithium-lead eutectic (Pb-17Li)

International Nuclear Information System (INIS)

Forcey, K.S.; Perujo, A.

1995-01-01

The permeation of deuterium through coated stainless steel tubes containing liquid lithium-lead eutectic (Pb-17Li) has been studied and compared to measurements through tubes without the lithium compound. The measurements form part of an investigation into the effect of a potential tritium breeder material on permeation barriers for fusion reactors. The coatings studied were CVD TiC and Al 2 O 3 and a pack aluminised layer. Without the lithium-lead, the CVD coatings reduced the permeation rate up to 1 order of magnitude, and the aluminised layer up to 2 orders of magnitude. A CVD layer was unaffected by Pb-17Li whilst in the case of the aluminised tube, the lithium-lead completely removed the permeation barrier, presumably by attacking the surface oxide. Furthermore, the aluminised sample presented a large number of cracks and poor adheren ce to the substrate. ((orig.))

Comparative study of silver nanoparticle permeation using Side-Bi-Side and Franz diffusion cells

Science.gov (United States)

Trbojevich, Raul A.; Fernandez, Avelina; Watanabe, Fumiya; Mustafa, Thikra; Bryant, Matthew S.

2016-03-01

Better understanding the mechanisms of nanoparticle permeation through membranes and packaging polymers has important implications for the evaluation of drug transdermal uptake, in food safety and the environmental implications of nanotechnology. In this study, permeation of 21 nm diameter silver nanoparticles (AgNPs) was tested using Side-Bi-Side and Franz static diffusion cells through hydrophilic 0.1 and 0.05 µm pore diameter 125 µm thick synthetic cellulose membranes, and 16 and 120 µm thick low-density polyethylene (LDPE) films. Experiments performed with LDPE films discarded permeation of AgNPs or Ag ions over the investigated time-frame in both diffusion systems. But controlled release of AgNPs has been quantified using semipermeable hydrophilic membranes. The permeation followed a quasi-linear time-dependent model during the experimental time-frame, which represents surface reaction-limited permeation. Diffusive flux, diffusion coefficients, and membrane permeability were determined as a function of pore size and diffusion model. Concentration gradient and pore size were key to understand mass transfer phenomena in the diffusion systems.

Comparative study of silver nanoparticle permeation using Side-Bi-Side and Franz diffusion cells

International Nuclear Information System (INIS)

Trbojevich, Raul A.; Fernandez, Avelina; Watanabe, Fumiya; Mustafa, Thikra; Bryant, Matthew S.

2016-01-01

Better understanding the mechanisms of nanoparticle permeation through membranes and packaging polymers has important implications for the evaluation of drug transdermal uptake, in food safety and the environmental implications of nanotechnology. In this study, permeation of 21 nm diameter silver nanoparticles (AgNPs) was tested using Side-Bi-Side and Franz static diffusion cells through hydrophilic 0.1 and 0.05 µm pore diameter 125 µm thick synthetic cellulose membranes, and 16 and 120 µm thick low-density polyethylene (LDPE) films. Experiments performed with LDPE films discarded permeation of AgNPs or Ag ions over the investigated time-frame in both diffusion systems. But controlled release of AgNPs has been quantified using semipermeable hydrophilic membranes. The permeation followed a quasi-linear time-dependent model during the experimental time-frame, which represents surface reaction-limited permeation. Diffusive flux, diffusion coefficients, and membrane permeability were determined as a function of pore size and diffusion model. Concentration gradient and pore size were key to understand mass transfer phenomena in the diffusion systems.Graphical Abstract

Comparative study of silver nanoparticle permeation using Side-Bi-Side and Franz diffusion cells

Energy Technology Data Exchange (ETDEWEB)

Trbojevich, Raul A. [U.S. Food and Drug Administration, Division of Biochemical Toxicology, National Center for Toxicological Research (United States); Fernandez, Avelina, E-mail: velifdez@ific.uv.es [Consejo Superior de Investigaciones Científicas-Universitat de València, Parc Científic, Instituto de Física Corpuscular (Spain); Watanabe, Fumiya; Mustafa, Thikra [University Arkansas at Little Rock, Center for Integrative Nanotechnology Sciences (United States); Bryant, Matthew S. [U.S. Food and Drug Administration, Division of Biochemical Toxicology, National Center for Toxicological Research (United States)

2016-03-15

Better understanding the mechanisms of nanoparticle permeation through membranes and packaging polymers has important implications for the evaluation of drug transdermal uptake, in food safety and the environmental implications of nanotechnology. In this study, permeation of 21 nm diameter silver nanoparticles (AgNPs) was tested using Side-Bi-Side and Franz static diffusion cells through hydrophilic 0.1 and 0.05 µm pore diameter 125 µm thick synthetic cellulose membranes, and 16 and 120 µm thick low-density polyethylene (LDPE) films. Experiments performed with LDPE films discarded permeation of AgNPs or Ag ions over the investigated time-frame in both diffusion systems. But controlled release of AgNPs has been quantified using semipermeable hydrophilic membranes. The permeation followed a quasi-linear time-dependent model during the experimental time-frame, which represents surface reaction-limited permeation. Diffusive flux, diffusion coefficients, and membrane permeability were determined as a function of pore size and diffusion model. Concentration gradient and pore size were key to understand mass transfer phenomena in the diffusion systems.Graphical Abstract.

Research on preparation of phosphate-modified animal glue binder for foundry use

Science.gov (United States)

Wang, Tian-Shu; Liu, Wei-Hua; Li, Ying-Min

2018-03-01

In this paper, three phosphates were used as modifiers to modify animal glue binder. The structural characteristics and thermal properties of animal glue binder treated with phosphates were studied by Fourier transform-infrared spectroscopy, gel permeation chromatography and derivative thermogravimetric analysis. The results showed that the modified animal glue binder had better sand tensile strength and lower viscosity than untreated animal glue binder. The best modification process was as follows: the optimal amount of sodium carbonate was 4 wt% to animal glue; the optimal weight ratio of the modifiers was sodium pyrophosphate : sodium tripolyphosphate : sodium hexametaphosphate : animal glue = 3 : 3 : 4 : 100, and the optimal reaction should be performed at 80°C for a reaction time of 120 min. A final tensile strength of approximately 3.20 MPa was achieved and the viscosity value was approximately 880 mPa s.

Preparation of microspheres containing methyl methacrylate (MMA) with magnetic nanoparticles; Preparacao de microesferas contendo metacrilato de metila (PMMA) com nanoparticulas magneticas

Energy Technology Data Exchange (ETDEWEB)

Feuser, P.E.; Souza, M.N. de, E-mail: paulofeuser@hotmail.co, E-mail: nele@eq.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Dept. de Engenharia Quimica

2010-07-01

Magnetic nanoparticles have found many technological applications and has been intensively studied due to its special magnetic properties. In most biomedical applications, microspheres containing magnetic nanoparticles is used as a vehicle for transporting drugs, presenting several advantages when compared to other conventional methods. PMMA is a polymer which has biocompatibility and can be used for the encapsulation of magnetic nanoparticles, showing a great degree of saturation magnetization. PMMA microparticles containing magnetic nanoparticles were prepared by suspension polymerization. Polymers containing magnetic nanoparticles were characterized by X-ray diffraction (XRD), vibrating sample magnetization, thermogravimetric analysis, optical microscopy, chromatography gel permeation, analysis of particle size - malversizer 2000 (Malvern Instruments). The average size of magnetic nanoparticles was approximately 150 {mu}m and depending on the amount of magnetic nanoparticles in the reaction medium Mw of microspheres can be altered. (author)

In vitro degradation of poly (L-co-D,L lactic acid containing PCL-T

Directory of Open Access Journals (Sweden)

Marcia Adriana Tomaz Duarte

2014-01-01

Full Text Available The application of polymer-based bioresorbable temporary devices in the medical field grows continuously, and professionals from several areas act to solve problems related to body functions lost due to diseases, accidents or natural wear. Here we study the influence from poly(caprolactonetriol (PCL-T on the degeneration process in the copolymer poly(L-co-DL-lactic acid (PLDLA membrane, by producing PLDLA/PCL-T blends with 90/10, 70/30 and 50/50 relative concentrations. The data for in vitro degradation showed that PCL-T decreases the rate of PLDLA. This was obtained with the following techniques: Differential Scanning Calorimetry (DSC, Thermogravimetric Analysis (TGA, Gel Permeation Chromatography (GPC and Scanning Electron Microscopy (SEM. Therefore, it is possible to vary the membrane degradation rate by changing the blend composition, which is a tool to tailor a biomaterial.

Synthesis and characterization of acrylate copolymer containing fluorescein functional group

Energy Technology Data Exchange (ETDEWEB)

Hui, Guodong; Huang, Weiyun; Song, Yunzhao; Chen, Deben; Zhong, Anyong [Sichuan University, Chengdu (China)

2013-08-15

We report a novel method to fabricate fluorescent polymer (F-CPA) based on the esterification between acrylate copolymer (CPA) and fluorescein using N, N-dicyclohexylcarbodiimide (DCC)/4-dimethylaminopyridine (DMAP) as catalyst. The resulting copolymer was characterized by Fourier transform-infrared spectroscopy (FT-IR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), ultraviolet-visible spectroscopy (UV-Vis) and fluorescence spectroscopy. In addition, the influences of concentration, solvents, pH and metal cations (Cu{sup 2+}, Fe{sup 3+} and Zn{sup 2+}) on the fluorescent behaviors of F-CPA are discussed in detail. All those observations suggest that the synthesized F-CPA is an excellent luminescent macromolecular material with simple synthesis method and excellent solubility. Moreover, its sensitive fluorescence response behaviors to solvents, pH and metal cations make it to become a polymer-based probe.

A Thermogravimetric Study of the Behaviour of Biomass Blends During Combustion

Directory of Open Access Journals (Sweden)

Ivo Jiříček

2012-01-01

Full Text Available The ignition and combustion behavior of biomass and biomass blends under typical heating conditions were investigated. Thermogravimetric analyses were performed on stalk and woody biomass, alone and blended with various additive weight ratios. The combustion process was enhanced by adding oxygen to the primary air. This led to shorter devolatilization/pyrolysis and char burnout stages, which both took place at lower temperatures than in air alone. The results of the ignition study of stalk biomass show a decrease in ignition temperature as the particle size decreases. This indicates homogeneous ignition, where the volatiles burn in the gas phase, preventing oxygen from reaching the particle surface.The behavior of biomass fuels in the burning process was analyzed, and the effects of heat production and additive type were investigated. Mixing with additives is a method for modifying biofuel and obtaining a more continuous heat release process. Differential scanning calorimetric-thermogravimetric (DSC-TGA analysis revealed that when the additive is added to biomass, the volatilization rate is modified, the heat release is affected, and the combustion residue is reduced at the same final combustion temperature.

Modell experiments to determine the effect of inhibitive oxide layers on metals against hydrogen permeation

International Nuclear Information System (INIS)

Zink, U.

1983-11-01

The coupling of H 2 -permeation and corrosion has been examined with the high-temperature alloys Incoloy 800 and Incoloy 802. Permeationsrates as well as corrosionsrates have been measured simultanously under H 2 O-H 2 atmospheres in the test-facility HD-PERM. Test parameters have been temperature and oxidationpotential. Parabolic laws for the growth of the oxide scales have been identified and are considered to be highly important for the efficiency of a permeation barrier. A comparison between the temperature dependencies of corrosionsrates and H 2 -permeationsrates has revealed that permeation and corrosion are coupled only in so far that the permeation barrier is formed by the corrosion reaction. The corrosion data (parabolic rate constant, activation energy) of the oxide scales have given clear indications for the existence of a Cr 2 O 3 -layer, which is considered to be responsible for efficient oxide permeation barriers. (orig.) [de

Enhanced skin permeation of naltrexone by pulsed electromagnetic fields in human skin in vitro.

Science.gov (United States)

Krishnan, Gayathri; Edwards, Jeffrey; Chen, Yan; Benson, Heather A E

2010-06-01

The aim of the present study was to evaluate the skin permeation of naltrexone (NTX) under the influence of a pulsed electromagnetic field (PEMF). The permeation of NTX across human epidermis and a silicone membrane in vitro was monitored during and after application of the PEMF and compared to passive application. Enhancement ratios of NTX human epidermis permeation by PEMF over passive diffusion, calculated based on the AUC of cumulative NTX permeation to the receptor compartment verses time for 0-4 h, 4-8 h, and over the entire experiment (0-8 h) were 6.52, 5.25, and 5.66, respectively. Observation of the curve indicated an initial enhancement of NTX permeation compared to passive delivery whilst the PEMF was active (0-4 h). This was followed by a secondary phase after termination of PEMF energy (4-8 h) in which there was a steady increase in NTX permeation. No significant enhancement of NTX penetration across silicone membrane occurred with PEMF application in comparison to passively applied NTX. In a preliminary experiment PEMF enhanced the penetration of 10 nm gold nanoparticles through the stratum corneum as visualized by multiphoton microscopy. This suggests that the channels through which the nanoparticles move must be larger than the 10 nm diameter of these rigid particles. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association

40 CFR 1060.102 - What permeation emission control requirements apply for fuel lines?

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What permeation emission control... AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EVAPORATIVE EMISSIONS FROM NEW AND IN-USE NONROAD AND STATIONARY EQUIPMENT Emission Standards and Related Requirements § 1060.102 What permeation...

40 CFR 1060.103 - What permeation emission control requirements apply for fuel tanks?

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What permeation emission control... AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EVAPORATIVE EMISSIONS FROM NEW AND IN-USE NONROAD AND STATIONARY EQUIPMENT Emission Standards and Related Requirements § 1060.103 What permeation...

Permeation of hydrogen at low pressures through stainless steel and implications for tritium control in fusion reactor systems

International Nuclear Information System (INIS)

Axtmann, R.C.; Johnson, E.F.; Kuehler, C.W.

1976-01-01

New experimental data on the permeation of hydrogen through stainless steel indicate that at driving pressures below 10 -2 torr, the permeation rate is linearly dependent on the driving pressure. A possible consequence is that the permeation rates of hydrogenic species in fusion reactor systems might be much lower than those reported in contemporary conceptual design studies which assume that the rates are dependent on the square root of the driving pressure. The important implications of these low permeation rates are: (1) tritium losses to the environment may be more dependent on ordinary leaks from equipment than on permeation to the steam cycle; (2) recovery of tritium from breeding blankets via permeation windows may be impracticable; and (3) recovery of tritium from breeding blankets not dependent on permeation windows may be simplified by the possibility of operating at much higher average tritium concentrations in the blanket and cooling systems

Effect of pressure sensitive adhesive and vehicles on permeation of terbinafine across porcine hoof membrane.

Science.gov (United States)

Ahn, Tai Sang; Lee, Jung-Phil; Kim, Juhyun; Oh, Seaung Youl; Chun, Myung-Kwan; Choi, Hoo-Kyun

2013-11-01

The purpose of this study was to investigate characteristics of transungual drug delivery and the feasibility of developing a drug-in-adhesive formulation of terbinafine. The permeation of terbinafine from a PSA matrix across porcine hoof membrane was determined using a plate containing poloxamer gel. The permeation rate of terbinafine across hairless mouse skin was evaluated using a flow-through diffusion cell system. The permeation of terbinafine across the hoof membranes was the highest from the silicone adhesive matrix, followed by PIB, and most of the acrylic adhesives, SIS, and SBS. The rank order of permeation rate across mice skin was different from the rank order across porcine hooves. The amount of terbinafine permeated across the porcine hoof membranes poorly correlated with the amount of terbinafine remaining inside the hooves after 20 days, however, the ratio between rate of terbinafine partitioning into the hoof membrane and its rate of diffusion across the membrane was relatively constant within the same type of PSA. For influence of various vehicles in enhancing permeation of terbinafine across the hoof membrane, all vehicles except Labrasol(®) showed tendency to improve permeation rate. However, the enhancement ratio of a given vehicle differed from one adhesive to another with a moderate correlation between them. The infrared spectrum of the hoof treated with NMP, PPG 400 or PEG 200 indicated that the conformation of keratin changed from a non-helical to a helical structure.

Development of permeate flux model for municipal wastewater treatment using membrane bioreactor

International Nuclear Information System (INIS)

Geissler, S.; Zhou, H.; Zytner, R.; Melin, T.

2002-01-01

In municipal wastewater treatment, membrane filtration technologies receive great attention because they usually produce the better quality effluent, generate less sludge and require a smaller aeration tank volume. However, one main challenge of using membranes is membrane fouling, which results in a permeate flux decrease or transmembrane pressure increase over the time. Many efforts have been directed to develop the mechanistic permeate flux model to correlate the permeate flux with process parameters. However, their applicability has been largely thwarted due to complicated membrane fouling mechanisms and the interactions of many factors affecting the membrane bioreactor. This paper proposes a semi-empirical permeate flux model for the membrane bioreactor (MBR) process using ZENON immersed hollow fibre membrane modules. The semi-empirical model was proposed by assuming that the permeate flux is equal to transmembrane pressure divided by total resistance. The total resistance is divided into two components: an inside membrane resistance and an outer fouling layer resistance. These membrane resistances are then related to the ageing of membrane used. Good correlation was found between the predicted and measured flux, with the mean absolute deviation being less than 4%. The observations also identified some general rules for operating membrane systems. Ideally, it is advisable that high pressure periods be avoided as this leads to a faster increase of non-reversal membrane resistance. It was also observed that membrane preservatives should be washed out carefully prior to use. (author)

Whole glove permeation of cyclohexanol through disposable nitrile gloves on a dextrous robot hand: Fist clenching vs. non-clenching.

Science.gov (United States)

Mathews, Airek R; Que Hee, Shane S

2017-04-01

The differences in permeation parameters when a gloved dextrous robot hand clenched and did not were investigated with the dynamic permeation system described in the companion paper. Increased permeation through the gloves of the present study for cyclohexanol when the gloved hand clenched depended on glove thickness and porosity for cyclohexanol permeation. The Sterling glove, the thinnest and most porous, was the least protective. Hand clenching promoted more permeation for the Sterling glove in terms of breakthrough times, steady state permeation rate, and diffusion coefficient. The Safeskin glove showed increased permeation only for the steady state permeation rate but not breakthrough times or diffusion coefficient. The Blue and Purple gloves showed no differences when the hand was clenching or not. The correlational analysis supported differences between the clenching and non-clenching situations, and the risk assessment considered the worst and best scenarios relative to one and two hydrated hands that were and were not protected by specific gloves.

Tritium permeation through helium-heated steam generators of ceramic breeder blankets for DEMO

International Nuclear Information System (INIS)

Fuetterer, M.A.; Raepsaet, X.; Proust, E.

1994-01-01

The specifications of permeation barriers, tritium recovery process maintaining a very low tritium activity in the coolant, and control of the coolant chemistry, required the evaluation of the tritium losses through the steam generators and include the definition of its operating conditions by thermodynamic cycle calculations and its thermal-hydraulic design. For both tasks specific computer tools were developed. The obtained geometry, surface area, and temperature profiles along the heat exchanger tubes were then used to estimate the daily tritium permeation into the steam cycle. Steam oxidized Incoloy 800 austenitic stainless steel was identified as the best suited existing material; in nominal steady-state operation, the tritium escape into the steam cycle could be restricted to less than 10 Ci/d. Tritium permeation during temperature and pressure transients in the steam generator (destruction and possible self-healing of the permeation barrier) is identified to bear a large tritium release potential. Solutions are proposed. (from authors). 4 figs., 1 tab

Tritium permeation through helium-heated steam generators of ceramic breeder blankets for DEMO

Energy Technology Data Exchange (ETDEWEB)

Fuetterer, M A; Raepsaet, X; Proust, E

1994-12-31

The specifications of permeation barriers, tritium recovery process maintaining a very low tritium activity in the coolant, and control of the coolant chemistry, required the evaluation of the tritium losses through the steam generators and include the definition of its operating conditions by thermodynamic cycle calculations and its thermal-hydraulic design. For both tasks specific computer tools were developed. The obtained geometry, surface area, and temperature profiles along the heat exchanger tubes were then used to estimate the daily tritium permeation into the steam cycle. Steam oxidized Incoloy 800 austenitic stainless steel was identified as the best suited existing material; in nominal steady-state operation, the tritium escape into the steam cycle could be restricted to less than 10 Ci/d. Tritium permeation during temperature and pressure transients in the steam generator (destruction and possible self-healing of the permeation barrier) is identified to bear a large tritium release potential. Solutions are proposed. (from authors). 4 figs., 1 tab.

Optimisation of cosolvent concentration for topical drug delivery III--influence of lipophilic vehicles on ibuprofen permeation.

Science.gov (United States)

Watkinson, R M; Guy, R H; Oliveira, G; Hadgraft, J; Lane, M E

2011-01-01

Previously, we have reported the effects of water, ethanol, propylene glycol and various binary and ternary mixtures of these solvents on the permeation of ibuprofen in model membranes and in skin. The present study investigates the influence of lipophilic vehicles on the transport of ibuprofen in silicone membrane and in human skin. The permeation of ibuprofen was measured from mineral oil (MO), Miglyol® 812 (MG) and binary mixtures of MO and MG. The solubility of ibuprofen was 5-fold higher in MG than in MO, however, the permeation of ibuprofen from the pure vehicles and combinations of both was comparable in silicone membrane. Additionally, there were no significant differences in skin permeation for MO and MG vehicles. When the permeation of various hydrophilic and lipophilic vehicles is considered, a trend between flux values for the model membrane and skin is evident (r(2) = 0.71). The findings suggest that silicone membrane may provide information on qualitative trends in skin permeation for vehicles of diverse solubility and partition characteristics. Copyright © 2010 S. Karger AG, Basel.

Implantation measurements to determine tritium permeation in first wall structures

International Nuclear Information System (INIS)

Holland, D.F.; Causey, R.A.

1983-01-01

A principal safety concern for a D-T burning fusion reactor is release of tritium during routine operation. Tritium implantation into first wall structures, and subsequent permeation into coolants, is potentially an important source of tritium loss. This paper reports on an experiment in which an ion accelerator was used to implant deuterium atoms in a stainless steel disk to simulate tritium implantation in first wall structures. The permeation rate was measured under various operating conditions. These results were used in the TMAP computer code to determine potential tritium loss rates for fusion reactors

Implantation measurements to determine tritium permeation in first-wall structures

International Nuclear Information System (INIS)

Holland, D.F.; Causey, R.A.; Sattler, M.L.

1983-01-01

A principal safety concern for a D-T burning fusion reactor is release of tritium during routine operation. Tritium implantation into first-wall structures, and subsequent permeation into coolants, is potentially an important source of tritium loss. This paper reports on an experiment in which an ion accelerator was used to implant deuterium atoms in a stainless steel disk to simulate tritium implantation in first-wall structures. The permeation rate was measured under various operating conditions. These results were used in the TMAP computer code to determine potential tritium loss rates for fusion reactors

Rapidly assessing the activation conditions and porosity of metal-organic frameworks using thermogravimetric analysis.

Science.gov (United States)

McDonald, Thomas M; Bloch, Eric D; Long, Jeffrey R

2015-03-25

A methodology utilizing a thermogravimetric analyzer to monitor propane uptake following incremental increases of the temperature is demonstrated as a means of rapidly identifying porous materials and determining the optimum activation conditions of metal-organic frameworks.

Manilkara zapota (Linn.) Seeds: A Potential Source of Natural Gum.

Science.gov (United States)

Singh, Sudarshan; Bothara, Sunil B

2014-01-01

Mucilage isolated from seeds of Manilkara zapota (Linn.) P. Royen syn. is a plant growing naturally in the forests of India. This mucilage is yet to be commercially exploited, and characterized as polymer. Various physicochemical methods like particle size analysis, scanning electron microscopy, thermal analysis, gel permeation chromatography, X-ray diffraction spectrometry, zeta potential, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy have been employed to characterize this gum in the present study. Particle size analyses suggest that mucilage has particle size in nanometer. Scanning electron microscopy analysis suggests that the mucilage has irregular particle size. The glass transition temperature of the gum was observed to be 138°C and 136°C by differential scanning calorimetry and differential thermal analysis, respectively. The thermogravimetric analysis suggested that mucilage had good thermal stability. The average molecular weight of mucilage was determined to be 379180, by gel permeation chromatography, while the viscosity of mucilage was observed to be 219.1 cP. The X-ray diffraction spectrometry pattern of the mucilage indicates a completely amorphous structure. Elemental analysis of the gum revealed the contents of carbon, hydrogen, nitrogen, and sulfur to be 80.9 (%), 10.1 (%), 1.58 (%), and 512 (mg/kg), respectively. Mucilage had specific content of calcium, magnesium, potassium, lower concentrations of aluminum, cadmium, cobalt, lead, and nickel. The major functional groups identified from FT-IR spectrum include 3441 cm(-1) (-OH), 1660 cm(-1) (Alkenyl C-H & C=C Stretch), 1632 cm(-1) (-COO-), 1414 cm(-1) (-COO-), and 1219 cm(-1) (-CH3CO). Analysis of mucilage by paper chromatography and 1D NMR, indicated the presence of rhamnose, xylose, arabinose, mannose, and fructose.

Effects of Vehicles and Enhancers on the Skin Permeation of Phytoestrogenic Diarylheptanoids from Curcuma comosa.

Science.gov (United States)

Tuntiyasawasdikul, Sarunya; Limpongsa, Ekapol; Jaipakdee, Napaphak; Sripanidkulchai, Bungorn

2017-04-01

Curcuma comosa (C. comosa) is widely used in traditional medicine as a dietary supplement for health promotion in postmenopausal women in Thailand. It contains several diarylheptanoids, which are considered to be a novel class of phytoestrogens. However, the diarylheptanoids isolated from the plant rhizome are shown to have low oral bioavailability and faster elimination characteristics. The aim of this study was to investigate the permeation behavior of the active compounds of diarylheptanoids. The effects of binary vehicle systems and permeation enhancers on diarylheptanoids permeation and accumulation within the skin were studied using side-by-side diffusion cells through the porcine ear skin. Among the tested binary vehicle systems, the ethanol/water vehicle appeared to be the most effective system for diarylheptanoids permeation with the highest flux and shortest lag time. The presence of transcutol in the vehicle system significantly increased diarylheptanoid's permeation and accumulation within the skin in a concentration-dependent manner. Although the presence of terpenes in formulation decreased the flux of diarylheptanoids, it raised the amount of diarylheptanoids retained within the skin substantially. Based on the feasibility of diarylheptanoid permeation, C. comosa extract should be further developed into an effective transdermal product for health benefits and hormone replacement therapy.

Skin permeation of D-limonene-based nanoemulsions as a transdermal carrier prepared by ultrasonic emulsification.

Science.gov (United States)

Lu, Wen-Chien; Chiang, Been-Huang; Huang, Da-Wei; Li, Po-Hsien

2014-03-01

Nanoemulsions can be used for transporting pharmaceutical phytochemicals in skin-care products because of their stability and rapid permeation properties. However, droplet size may be a critical factor aiding permeation through skin and transdermal delivery efficiency. We prepared D-limonene nanoemulsions with various droplet sizes by ultrasonic emulsification using mixed surfactants of sorbitane trioleate and polyoxyethylene (20) oleyl ether under different hydrophilic-lipophilic balance (HLB) values. Droplet size decreased with increasing HLB value. With HLB 12, the droplet size was 23 nm, and the encapsulated ratio peaked at 92.3%. Transmission electron microscopy revealed spherical droplets and the gray parts were D-limonene precipitation incorporated in spherical droplets of the emulsion system. Franz diffusion cell was used to evaluate the permeation of D-limonene nanoemulsion through rat abdominal skin; the permeation rate depended on droplet size. The emulsion with the lowest droplet size (54 nm) achieved the maximum permeation rate. The concentration of D-limonene in the skin was 40.11 μL/cm(2) at the end of 360 min. Histopathology revealed no distinct voids or empty spaces in the epidermal region of permeated rat skin, so the D-limonene nanoemulsion may be a safe carrier for transdermal drug delivery. Copyright © 2013 Elsevier B.V. All rights reserved.

Intact penetratin metabolite permeates across Caco-2 monolayers

DEFF Research Database (Denmark)

Birch, Ditlev; Christensen, Malene Vinther; Stærk, Dan

. Previous studies have demonstrated that cell-penetrating peptides (CPPs) may be used as carriers in order to improve the bioavailability of a therapeutic cargo like insulin after oral administration. Penetratin, a commonly used CPP, has been shown to increase the uptake of insulin across Caco-2 cell......-2 cells cultured on permeable filter inserts and in cell lysates, respectively. The epithelial permeation of penetratin and the formed metabolites was assessed by using Caco-2 monolayers cultured on permeable filter inserts. Results Preliminary data revealed that at least one specific metabolite...... is formed upon both intracellular and extracellular degradation of penetratin (figure 1A). Following incubation with epithelium for 4 hours, the metabolite permeated the Caco-2 monolayer and the concentration increased approximately 10-fold when compared to a sample collected following 15 minutes...

Gas Permeation Characteristics across Nano-Porous Inorganic Membranes

Directory of Open Access Journals (Sweden)

M.R Othman, H. Mukhtar

2012-10-01

Full Text Available An overview of parameters affecting gas permeation in inorganic membranes is presented. These factors include membrane physical characteristics, operational parameters and gas molecular characteristics. The membrane physical characteristics include membrane materials and surface area, porosity, pore size and pore size distribution and membrane morphology. The operational parameters include feed flow rate and concentration, stage cut, temperature and pressure. The gas molecular characteristics include gas molecular weight, diameter, critical temperature, critical pressure, Lennard-Jones parameters and diffusion volumes. The current techniques of material characterization may require complementary method in describing microscopic heterogeneity of the porous ceramic media. The method to be incorporated in the future will be to apply a stochastic model and/or fractal dimension. Keywords: Inorganic membrane, surface adsorption, Knudsen diffusion, Micro-porous membrane, permeation, gas separation.

Permeation of antigen protein-conjugated nanoparticles and live bacteria through microneedle-treated mouse skin

Science.gov (United States)

Kumar, Amit; Li, Xinran; Sandoval, Michael A; Rodriguez, B Leticia; Sloat, Brian R; Cui, Zhengrong

2011-01-01

Background: The present study was designed to evaluate the extent to which pretreatment with microneedles can enhance skin permeation of nanoparticles in vitro and in vivo. Permeation of live bacteria, which are physically nanoparticles or microparticles, through mouse skin pretreated with microneedles was also studied to evaluate the potential risk of microbial infection. Methods and results: It was found that pretreatment of mouse skin with microneedles allowed permeation of solid lipid nanoparticles, size 230 nm, with ovalbumin conjugated on their surface. Transcutaneous immunization in a mouse skin area pretreated with microneedles with ovalbumin nanoparticles induced a stronger antiovalbumin antibody response than using ovalbumin alone. The dose of ovalbumin antigen determined whether microneedle-mediated transcutaneous immunization with ovalbumin nanoparticles induced a stronger immune response than subcutaneous injection of the same ovalbumin nanoparticles. Microneedle treatment permitted skin permeation of live Escherichia coli, but the extent of the permeation was not greater than that enabled by hypodermic injection. Conclusion: Transcutaneous immunization on a microneedle-treated skin area with antigens carried by nanoparticles can potentially induce a strong immune response, and the risk of bacterial infection associated with microneedle treatment is no greater than that with a hypodermic injection. PMID:21753877

Quantitation of Surface Coating on Nanoparticles Using Thermogravimetric Analysis.

Science.gov (United States)

Dongargaonkar, Alpana A; Clogston, Jeffrey D

2018-01-01

Nanoparticles are critical components in nanomedicine and nanotherapeutic applications. Some nanoparticles, such as metallic nanoparticles, consist of a surface coating or surface modification to aid in its dispersion and stability. This surface coating may affect the behavior of nanoparticles in a biological environment, thus it is important to measure. Thermogravimetric analysis (TGA) can be used to determine the amount of coating on the surface of the nanoparticle. TGA experiments run under inert atmosphere can also be used to determine residual metal content present in the sample. In this chapter, the TGA technique and experimental method are described.

Deuterium gas-driven permeation and subsequent retention in rolled tungsten foils

International Nuclear Information System (INIS)

Liu, Feng; Zhou, Haishan; Li, Xiao-Chun; Xu, Yuping; An, Zhongqing; Mao, Hongmin; Xing, Wenjing; Hou, Qing; Luo, Guang-Nan

2014-01-01

Experiments concerning deuterium gas-driven permeation through rolled tungsten foils in the temperature range of 850–950 K and subsequent deuterium retention have been performed. The steady state permeation flux of deuterium is proportional to the square root of the driving pressure. The permeability of deuterium is in an order of 10 −14 mol m −1 s −1 Pa −1/2 in this temperature range and the activation energy for permeation is 1.21 eV. Measurements of diffusivity are significantly affected by the driving pressure, which can be well explained by a saturable-trap model. Thermal desorption spectra of samples feature a single deuterium release peak at about 873 K. TMAP 4 modeling of this peak gives a detrapping energy of 1.70 eV, which fits the dissociation enthalpy of deuterium desorbing from the inner wall of vacancy clusters or pores in tungsten

Deuterium gas-driven permeation and subsequent retention in rolled tungsten foils

Science.gov (United States)

Liu, Feng; Zhou, Haishan; Li, Xiao-Chun; Xu, Yuping; An, Zhongqing; Mao, Hongmin; Xing, Wenjing; Hou, Qing; Luo, Guang-Nan

2014-12-01

Experiments concerning deuterium gas-driven permeation through rolled tungsten foils in the temperature range of 850-950 K and subsequent deuterium retention have been performed. The steady state permeation flux of deuterium is proportional to the square root of the driving pressure. The permeability of deuterium is in an order of 10-14 mol m-1 s-1 Pa-1/2 in this temperature range and the activation energy for permeation is 1.21 eV. Measurements of diffusivity are significantly affected by the driving pressure, which can be well explained by a saturable-trap model. Thermal desorption spectra of samples feature a single deuterium release peak at about 873 K. TMAP 4 modeling of this peak gives a detrapping energy of 1.70 eV, which fits the dissociation enthalpy of deuterium desorbing from the inner wall of vacancy clusters or pores in tungsten.

Experimental evaluation of tritium permeation through stainless steel tubes of heat exchanger from primary to secondary water in ITER

International Nuclear Information System (INIS)

Nakamura, Hirofumi; Nishi, Masataka

2004-01-01

Tritium permeation through heat exchanger from primary cooling water to secondary cooling water has been investigated experimentally with SS316L heat exchanger under simulated ITER (international thermonuclear experimental reactor) operation condition in order to establish the tritium permeation evaluation method through the heat exchanger. As the result, the permeation rate of aqueous tritium was found to be about three orders smaller than that of the gaseous tritium. Tritium permeation through the heat exchanger in ITER was then evaluated, and it was revealed that total tritium permeation amount based on obtained aqueous permeability was about one order less than that with the former method with the gaseous permeability and putting the permeation reduction factor as 1000. Evaluated tritium permeation amount into secondary water during 20 years was quite small, which could be considered as negligible from the safety viewpoint

Combined use of bile acids and aminoacids to improve permeation properties of acyclovir.

Science.gov (United States)

Cirri, M; Maestrelli, F; Mennini, N; Mura, P

2015-07-25

The aim of this work was to develop a topical formulation with improved permeation properties of acyclovir. Ursodeoxycholic (UDC) and dehydrocholic (DHC) acids were tested as potential enhancers, alone or in combination with different aminoacids. Equimolar binary and ternary systems of acyclovir with cholic acids and basic, hydrophilic or hydrophobic aminoacids were prepared by co-grinding in a high vibrational micromill. Differential scanning calorimetry (DSC) was used to characterize the solid state of these systems, while their permeation properties were evaluated in vitro through a lipophilic artificial membrane. UDC was more than 2 times more effective than DHC in improving drug AUC and permeation rate. As for the ternary systems drug-UDC-aminoacid, only the combined use of l-lysine with UDC acid produced an evident synergistic effect in enhancing drug permeation properties, enabling an almost 3 and 8 times AUC increase compared to the binary UDC system or the pure drug, respectively. The best systems were selected for the development of topical cream formulations, adequately characterized and tested for in vitro drug permeation properties and stability on storage. The better performance revealed by acyclovir-UDC-l-lysine was mainly attributed to the formation of a more permeable activated system induced by the multicomponent co-grinding process. Copyright © 2015 Elsevier B.V. All rights reserved.

Influence of bulk and surface phenomena on the hydrogen permeation through metals

International Nuclear Information System (INIS)

Waelbroeck, F.; Wienhold, P.; Winter, J.; Rota, E.; Bauno, T.

1984-12-01

We discuss the permeation of hydrogen through metals and alloys such as iron, nickel, steels and Inconel wherein H dissolves endothermically from an H 2 gas. We assume first that trapping centers, surface contamination layers, the saturation of the H surface coverage and the implantation profile - when energetic ions drive the permeation - can be neglected, that a quasi-equilibrium exists between the H atom concentration ν in the adsorbed layer and c in the near surface layers and that the H solubility and diffusivity are homogeneous in the membrane. We evaluate thereafter separately the influence of these various effects and identify the parameter domains where appreciable corrections result. The permeation phenomenon is complex even when these simplifications are made: the penetration rate is proportional to the flux of thermal molecules, atoms or energetic ions - depending upon the case - which strike the surface; the diffusion in the metal is proportional to the gradient of c; the release rate depends on c 2 ; the time-dependent diffusion equation includes a double spatial derivative of c. Permeation can only be fully described when computer codes such as PERI is used. Simple analytical relations are however obtained in several limiting cases. They are the object of this report. Some of them had already been derived by other authors but they were not shown to be part of a single, self consistent permeation model. A comparison of predicted and experimental results shows that the simplified model describes surprisingly accurately the hydrogen exchange between gas and metal solutions. (orig./GSCH)

Catalytic reforming of methane to syngas in an oxygen-permeative membrane reactor

Energy Technology Data Exchange (ETDEWEB)

Urano, Takeshi; Kubo, Keiko; Saito, Tomoyuki; Hitomi, Atsushi, E-mail: turano@jp.tdk.com [Materials and Process Development Center, TDK Corporation 570-2, Matsugashita, Minamihatori, Narita, Chiba 286-8588 (Japan)

2011-05-15

For fuel cell applications, partial oxidative reforming of methane to syngas, hydrogen and carbon monoxide, was performed via a dense oxygen-permeative ceramic membrane composed by both ionic and electronic conductive materials. The modification of Ni-based catalyst by noble metals was investigated to increase oxygen permeation flux and decrease carbon deposition during reforming reaction. The role of each component in catalyst was also discussed.

40 CFR 1060.520 - How do I test fuel tanks for permeation emissions?

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false How do I test fuel tanks for... STATIONARY EQUIPMENT Test Procedures § 1060.520 How do I test fuel tanks for permeation emissions? Measure permeation emissions by weighing a sealed fuel tank before and after a temperature-controlled soak. (a...

Production of citric acid from whey permeate by fermentation using Aspergillus niger

Energy Technology Data Exchange (ETDEWEB)

Hossain, M; Brooks, J D

1983-08-01

The use of lactic casein whey permeate as a substrate for citric acid production by fermentation has been investigated. Using a mutant strain of Aspergillus niger IMI 41874 in fermenter culture, a citric acid concentration of 8.3 g/l, representing a yield of 19% (w/w) based on lactose utilized, has been observed. Supplementation of the permeate with lactose (final concentration 140 g/l) increased the production to 14.8 g/l (yield 23%). The natural pH of the permeate (pH 4.5) was the most suitable initial pH for the process, and pH control during the fermentation was unnecessary. The addition of methanol (final concentration 3% v/v) to the fermentation increased the citric acid production to 25 g/l (yield 33%, based on lactose utilized). 13 references.

LIBRETTO-3: Performance of tritium permeation barriers under irradiation at the HFR Petten

International Nuclear Information System (INIS)

Conrad, R.; Fuetterer, M.A.; Giancarli, L.; May, R.; Perujo, A.; Sample, T.

1994-01-01

The LIBRETTO-3 irradiation was performed at the HFR Petten during 77 full power days in three cycles to compare the efficiency of three different tritium permeation barriers in presence of Pb-17Li to uncoated AISI 316L steel. For this purpose four steel capsules (arnothing o =10 mm, arnothing i =8 mm, l=300 mm) were filled with 28 g Pb-17Li. The coatings included CVD TiC (outside), CVD TiC+Al 2 O 3 (inside), and pack cementation aluminisation (inside). The generated tritium was partly extracted by bubbling, partly it permeated through the capsules. Permeated and extracted tritium were measured as a function of temperature (280-450 C), H 2 doping (0-1 vol%) and purge gas flow rate. The driving partial pressure in the coated capsules were from an extraction model calibrated by the uncoated capsule for which tritium partial pressure could be calculated. In LIBRETTO-3 conditons, the best barrier was pack cementation aluminisation. The first interpretation of the experiment could, however, not confirm permeation reduction factors of 100 or more expected from this barrier. ((orig.))

Deuterium gas-driven permeation and subsequent retention in rolled tungsten foils

Energy Technology Data Exchange (ETDEWEB)

Liu, Feng [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhou, Haishan [Department of Fusion Science, The Graduate University for Advanced Studies, Toki 509-5292 (Japan); Li, Xiao-Chun [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Xu, Yuping; An, Zhongqing [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026 (China); Mao, Hongmin; Xing, Wenjing [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Hou, Qing [Key Laboratory for Radiation Physics and Technology, Sichuan University, Chengdu 610061 (China); Luo, Guang-Nan, E-mail: gnluo@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026 (China)

2014-12-15

Experiments concerning deuterium gas-driven permeation through rolled tungsten foils in the temperature range of 850–950 K and subsequent deuterium retention have been performed. The steady state permeation flux of deuterium is proportional to the square root of the driving pressure. The permeability of deuterium is in an order of 10{sup −14} mol m{sup −1} s{sup −1} Pa{sup −1/2} in this temperature range and the activation energy for permeation is 1.21 eV. Measurements of diffusivity are significantly affected by the driving pressure, which can be well explained by a saturable-trap model. Thermal desorption spectra of samples feature a single deuterium release peak at about 873 K. TMAP 4 modeling of this peak gives a detrapping energy of 1.70 eV, which fits the dissociation enthalpy of deuterium desorbing from the inner wall of vacancy clusters or pores in tungsten.

A thermogravimetric analyzer for corrosive atmospheres, and its application to the chlorination of ZrO2-C mixtures

International Nuclear Information System (INIS)

Pasquevich, Daniel; Caneiro, Alberto

1990-01-01

A thermogravimetric analyzer built on the basis of a Cahn 2000 electrobalance, suitable for using with corrosive atmospheres, is reported. The corrections for buoyancy and gas-flow effects, which strongly modify the thermogravimetric curves are discussed. As an application, the kinetics of a reaction between chlorine and a mixture of zirconia and carbon has been studied. It has been able to measure the uptake of chlorine by carbon and the reaction rate within the first 50 seconds. Evidence of a transition to quite a different reaction rate at longer times is presented. (Author)

Isothermal thermogravimetric data acquisition analysis system

Science.gov (United States)

Cooper, Kenneth, Jr.

1991-01-01

The description of an Isothermal Thermogravimetric Analysis (TGA) Data Acquisition System is presented. The system consists of software and hardware to perform a wide variety of TGA experiments. The software is written in ANSI C using Borland's Turbo C++. The hardware consists of a 486/25 MHz machine with a Capital Equipment Corp. IEEE488 interface card. The interface is to a Hewlett Packard 3497A data acquisition system using two analog input cards and a digital actuator card. The system provides for 16 TGA rigs with weight and temperature measurements from each rig. Data collection is conducted in three phases. Acquisition is done at a rapid rate during initial startup, at a slower rate during extended data collection periods, and finally at a fast rate during shutdown. Parameters controlling the rate and duration of each phase are user programmable. Furnace control (raising and lowering) is also programmable. Provision is made for automatic restart in the event of power failure or other abnormal terminations. Initial trial runs were conducted to show system stability.

Deuterium permeation behavior of HTUPS4 steel with thermal oxidation layer

International Nuclear Information System (INIS)

Xu, Yu-Ping; Liu, Feng; Zhao, Si-Xiang; Li, Xiao-Chun; Wang, Jing; An, Zhong-Qing; Lu, Tao; Liu, Hao-Dong; Ding, Fang; Zhou, Hai-Shan; Luo, Guang-Nan

2016-01-01

The permeation behavior of creep-resistant, Al 2 O 3 -forming HTUPS austenitic stainless steels was studied using a gas driven permeation (GDP) device. The steel samples were first thermal oxidized at air condition, followed by GDP experiments. The permeability and diffusion coefficients of oxidized samples and bare 316L steels were derived and compared. In order to characterize the oxide layer, X-ray photoelectron spectroscopy was performed. An oxide layer with a thickness of 200 nm which mainly consists of Al 2 O 3 was detected.

Liposomal buccal mucoadhesive film for improved delivery and permeation of water-soluble vitamins.

Science.gov (United States)

Abd El Azim, Heba; Nafee, Noha; Ramadan, Alyaa; Khalafallah, Nawal

2015-07-05

This study aims at improving the buccal delivery of vitamin B6 (VB6) as a model highly water-soluble, low permeable vitamin. Two main strategies were combined; first VB6 was entrapped in liposomes, which were then formulated as mucoadhesive film. Both plain and VB6-loaded liposomes (LPs) containing Lipoid S100 and propylene glycol (∼ 200 nm) were then incorporated into mucoadhesive film composed of SCMC and HPMC. Results showed prolonged release of VB6 (72.65%, T50% diss 105 min) after 6h from LP-film compared to control film containing free VB6 (96.37%, T50% diss 30 min). Mucoadhesion was assessed both ex vivo on chicken pouch and in vivo in human. Mucoadhesive force of 0.2N and residence time of 4.4h were recorded. Ex vivo permeation of VB6, across chicken pouch mucosa indicated increased permeation from LP-systems compared to corresponding controls. Interestingly, incorporation of the vesicles in mucoadhesive film reduced the flux by 36.89% relative to LP-dispersion. Meanwhile, both films provided faster initial permeation than the liquid forms. Correlating the cumulative percent permeated ex vivo with the cumulative percent released in vitro indicated that LPs retarded VB6 release but improved permeation. These promising results represent a step forward in the field of buccal delivery of water-soluble vitamins. Copyright © 2015 Elsevier B.V. All rights reserved.

Construction and performance test of apparatus for permeation experiments with controlled surfaces

International Nuclear Information System (INIS)

Hatano, Yuji; Nomura, Mamoru; Watanabe, Kuniaki; Livshits, Alexander I.; Busnyuk, Andrei O.; Nakamura, Yukio; Ohyabu, Nobuyoshi

2003-01-01

A new apparatus was constructed to examine gas-, atom- and plasma-driven permeation of hydrogen isotopes through group VA metal membranes with precisely controlled surface states. Absorption and desorption experiments are also possible. The new apparatus consists of two vacuum chambers, an upstream chamber and a downstream chamber, separated by a specimen membrane. Both chambers are evacuated by turbo-molecular pumps and sputter-ion pumps. The upstream chamber is equipped with Ta filaments serving as atomizers in atom-driven permeation experiments and cathodes in plasma-driven permeation experiments. The specimen membrane is formed into a tubular shape and electrically isolated from the chamber. Hence, ohmic heating of the membrane is possible, and this feature of the membrane is suitable for surface cleaning by high-temperature heating an impurity doping for the control of surface chemical composition through surface segregation. Both chambers were evacuated to 1 x 10 -7 Pa after baking. The main component of residual gas was H 2 , and the partial pressures of impurity gases other than H 2 were ca. 1 x 10 -8 Pa. Gas- and atom-driven permeation experiments were successfully carried out with hydrogen gas for Nb membrane activated by heating in vacuum at 1173 K. Superpermeation was observed in the atom-driven permeation experiments. Absorption experiments with a clean surface were also carried out. The surface was, however, cleaned only partially, because the temperature distribution was not uniform during high-temperature heating. Nevertheless, surface cleanliness was retained during absorption experiments under the present vacuum conditions. A new membrane assembly that will enable a uniform temperature distribution is now under construction. (author)

Thermogravimetric studies on electron beam initiated grafting of triallyl cyanurate onto polyethylene

International Nuclear Information System (INIS)

Chaki, T.K.; Bhowmik, A.K.; Mukunda, P.G.; Majali, A.B.; Tikku, V.K.

1993-01-01

Low density polyethylene (LDPE) containing different levels of triallyl cyanurate (TAC) have been prepared in a Brabender Plasticorder at 120 degC. The moulded samples in the form of rectangular compression sheet were irradiated under electron beam accelerator with different irradiation doses. Thermogravimetric and derivative thermogravimetric analyses of the irradiated samples grafted with TAC have been carried out in order to explore the decomposition behaviour and kinetics of decomposition under nitrogen atmosphere. Initial decomposition temperature (Ti), temperature at which 50% weight loss takes place (T50), final decomposition temperature (Tf) and the kinetic parameters evaluated from TGA traces of samples at different radiation doses (constant TAC level) and at different levels of TAC (constant radiation dose) have been reported. The effect of radiation dose and TAC level on the grafting of TAC onto polyethylene have been explained on the basis of degradation characteristics of irradiated samples. Kinetic studies show that the degradation of the irradiated samples follow first order reaction kinetics. Activation energies of degradation have been determined using McCarty and Green's method. Activation energy of the irradiated samples increases with the increasing radiation dose and also with increasing level of TAC. (author). 3 tabs

Hydrogen permeation through metallic foils

International Nuclear Information System (INIS)

Bernardi, M.I.B.; Rodrigues, J.A.

1987-01-01

The process of electrolytic permeation of hydrogen through metallic foils is studied. A double electrolytic cell, in glass, in which the two compartments of reaction are separated by a metallic foil to be studied, was built. As direct result, the hydrogen diffusion coefficient in the metal is obtained. The hydrogen diffusion coefficients in the palladium and, in austenitic stainless steels 304 and 304 L, used in the Angra-1 reactor, were obtained. Samples of stainless steels with and without welding, were used. (Author) [pt

Water vapor permeation and dehumidification performance of poly(vinyl alcohol)/lithium chloride composite membranes

KAUST Repository

Bui, Duc Thuan

2015-10-09

Thin and robust composite membranes comprising stainless steel scaffold, fine and porous TiO2 and polyvinyl alcohol/lithium chloride were fabricated and studied for air dehumidification application. Higher hydrophilicity, sorption and permeation were observed for membranes with increased lithium chloride content up to 50%. The permeation and sorption properties of the membranes were investigated under different temperatures. The results provided a deeper insight into the membrane water vapor permeation process. It was specifically noted that lithium chloride significantly reduces water diffusion energy barrier, resulting in the change of permeation energy from positive to negative values. Higher water vapor permeance was observed for the membrane with higher LiCl content at lower temperature. The isothermal air dehumidification tests show that the membrane is suitable for dehumidifying air in high humid condition. Additionally, results also indicate a trade-off between the humidity ratio drop with the water vapor removal rate when varying air flowrate.

Characterization of an alkali-treated grass fiber by thermogravimetric and X-ray crystallographic analysis

NARCIS (Netherlands)

De, D.; De, Debapriya

2008-01-01

The thermal behavior of grass fiber was characterized by means of thermogravimetric analysis and differential scanning calorimetry analysis. The results proved that the removal of water-soluble matter improved the thermal behavior of grass fiber over that of unleached fiber, and this was further

A novel lipid nanoemulsion system for improved permeation of granisetron.

Science.gov (United States)

Doh, Hea-Jeong; Jung, Yunjin; Balakrishnan, Prabagar; Cho, Hyun-Jong; Kim, Dae-Duk

2013-01-01

A new lipid nanoemulsion (LNE) system containing granisetron (GRN) was developed and its in vitro permeation-enhancing effect was evaluated using Caco-2 cell monolayers. Particle size, polydispersity index (PI) and stability of the prepared GRN-loaded LNE systems were also characterized. The mean diameters of prepared LNEs were around 50 nm with PI<0.2. Developed LNEs were stable at 4°C in the dark place over a period of 12 weeks. In vitro drug dissolution and cytotoxicity studies of GRN-loaded LNEs were performed. GRN-loaded LNEs exhibited significantly higher drug dissolution than GRN suspension at pH 6.8 for 2h (P<0.05). In vitro permeation study in Caco-2 cell monolayers showed that the LNEs significantly enhanced the drug permeation compared to GRN powder. The in vivo toxicity study in the rat jejunum revealed that the prepared GRN-loaded LNE was as safe as the commercial formulation (Kytril). These results suggest that LNE could be used as a potential oral liquid formulation of GRN for anti-emetic treatment on the post-operative and chemotherapeutic patients. Copyright © 2012 Elsevier B.V. All rights reserved.

High permeation rates in liposome systems explain rapid glyphosate biodegradation associated with strong isotope fractionation.

Science.gov (United States)

Ehrl, Benno; Mogusu, Emmanuel O; Kim, Kyoungtea; Hofstetter, Heike; Pedersen, Joel A; Elsner, Martin

2018-05-23

Bacterial uptake of charged organic pollutants such as the widely used herbicide glyphosate is typically attributed to active transporters, whereas passive membrane permeation as an uptake pathway is usually neglected. For 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) liposomes, pH-dependent membrane permeation coefficients (Papp) of glyphosate, determined by nuclear magnetic resonance (NMR) spectroscopy, varied from Papp(pH 7.0) = 3.7 (+/-0.3) × 10-7 m∙s-1 to Papp(pH 4.1) = 4.2 (+/-0.1) × 10-6 m∙s-1. This surprisingly rapid membrane permeation depended on glyphosate speciation and was, at physiological pH, in the range of polar, non-charged molecules suggesting that passive membrane permeation is a potential uptake pathway during glyphosate biodegradation. To test this hypothesis, a Gram-negative glyphosate degrader, Ochrobactrum sp. FrEM, was isolated from glyphosate-treated soil and glyphosate permeation rates inferred from the liposome model were compared to bacterial degradation rates. Estimated maximum permeation rates were, indeed, two orders of magnitudes higher than glyphosate degradation rates. Moreover, biodegradation of millimolar glyphosate concentrations gave rise to pronounced carbon isotope fractionation with an apparent kinetic isotope effect of AKIEcarbon= 1.014 ± 0.003. This value is consistent with unmasked enzymatic isotope fractionation demonstrating that glyphosate biodegradation was little mass transfer-limited and glyphosate exchange across the cell membrane was rapid relative to enzymatic turnover.

Thermogravimetric analytical procedures for characterizing New Zealand and eastern Australian coals

Energy Technology Data Exchange (ETDEWEB)

Benfell, K.E.; Beamish, B.B.; Rodgers, K.A. [University of Auckland, Auckland (New Zealand). Dept. of Geology

1996-09-01

Under tightly constrained experimental conditions (particle size {lt}75 {mu}m, sample mass 5.0 {+-} 0.5 mg), heating rate 15{degree}C min{sup -1}, dry air purge 50 mL min{sup -1}, maximum temperature 900{degree}C a repeatability of {lt} {+-} 2{degree}C, may be achieved for significant temperatures that characterize the differential thermogravimetric burning profiles of typical medium-volatile, bituminous Australian Gondwanan coals and high-volatile, bituminous New Zealand Cretaceous-Tertiary coals.

Contaminant Permeation in the Ionomer-Membrane Water Processor (IWP) System

Science.gov (United States)

Kelsey, Laura K.; Finger, Barry W.; Pasadilla, Patrick; Perry, Jay

2016-01-01

The Ionomer-membrane Water Processor (IWP) is a patented membrane-distillation based urine brine water recovery system. The unique properties of the IWP membrane pair limit contaminant permeation from the brine to the recovered water and purge gas. A paper study was conducted to predict volatile trace contaminant permeation in the IWP system. Testing of a large-scale IWP Engineering Development Unit (EDU) with urine brine pretreated with the International Space Station (ISS) pretreatment formulation was then conducted to collect air and water samples for quality analysis. Distillate water quality and purge air GC-MS results are presented and compared to predictions, along with implications for the IWP brine processing system.

The impact of tritium solubility and diffusivity on inventory and permeation in liquid breeder blankets

International Nuclear Information System (INIS)

Caorlin, M.; Gervasini, G.; Reiter, F.

1988-01-01

The authors reviewed hydrogen solubility and diffusivity data for liquid lithium-based compounds which are potential breeding blanket materials in NET-type fusion devices. These data have been used to assess tritium permeation and inventory in separately cooled NET blankets and in self cooled blankets with a vanadium first wall. The results for the separately cooled NET-liquid breeder show that tritium permeation is negligible for lithium, a serious problem for Pb-17Li and a critical one for Flibe. The total tritium inventory is lowest in lithium, high in Pb-17Li and very high in Flibe. The high tritium partial pressure for Flibe or Pb-17Li can be reduced in a self cooled blanket with a vanadium first wall. Permeation into the plasma reduces the blanket tritium inventory and permeation. Tritium recovery can be combined with the plasma exhaust

Crosslinked bicontinuous biobased PLA/NR blends via dynamic vulcanization using different curing systems.

Science.gov (United States)

Yuan, Daosheng; Chen, Kunling; Xu, Chuanhui; Chen, Zhonghua; Chen, Yukun

2014-11-26

In this study, blends of entirely biosourced polymers, namely polylactide (PLA) and natural rubber (NR), were prepared through dynamic vulcanization using dicumyl peroxide (DCP), sulphur (S) and phenolic resin (2402) as curing agents, respectively. The crosslinked NR phase was found to be a continuous structure in all the prepared blends. The molecular weight changes of PLA were studied by gel permeation chromatography. Interfacial compatibilization between PLA and NR was investigated using Fourier transform infrared spectroscopy and scanning electron microscopy. The thermal properties of blends were evaluated by differential scanning calorimetry and thermogravimetric analysis instrument. It was found that the molecular weight of PLA and interfacial compatibilizaion between PLA and NR showed a significant influence on the mechanical and thermal properties of blends. The PLA/NR blend (60/40 w/w) by DCP-induced dynamic vulcanization owned the finest mechanical properties and thermal stability. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation of poly (styrene)-b-poly (acrylic acid)/{gamma}-Fe{sub 2}O{sub 3} composites

Energy Technology Data Exchange (ETDEWEB)

Zhang, L.D. [School of Materials Science and Engineering, Shandong Polytechnic University, Key Laboratory of Processing and Testing Technology of Glass Functional Ceramics of Shandong Province, Daxue Road, Western University Science Park, Jinan 250353 (China); Liu, W.L., E-mail: wlliu@sdu.edu.cn [School of Materials Science and Engineering, Shandong Polytechnic University, Key Laboratory of Processing and Testing Technology of Glass Functional Ceramics of Shandong Province, Daxue Road, Western University Science Park, Jinan 250353 (China); Xiao, C.L.; Yao, J.S.; Fan, Z.P.; Sun, X.L.; Zhang, X.; Wang, L. [School of Materials Science and Engineering, Shandong Polytechnic University, Key Laboratory of Processing and Testing Technology of Glass Functional Ceramics of Shandong Province, Daxue Road, Western University Science Park, Jinan 250353 (China); Wang, X.Q. [State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China)

2011-12-15

The use of a block copolymer, poly (styrene)-b-poly (acrylic acid) (PS-b-PAA) to prepare a magnetic nanocomposite was investigated. Poly (styrene)-poly (t-butyl acrylate) block copolymer, being synthesized by atom transfer radical polymerization, was hydrolyzed with hydrochloric acid for obtaining PS-b-PAA. The obtained PS-b-PAA was then compounded with the modified {gamma}-Fe{sub 2}O{sub 3}, and subsequently the magnetic nanocomposite was achieved. The products were characterized by {sup 1}H NMR, FTIR, gel permeation chromatography, thermogravimetric analysis, transmission electron microscopy and vibrating sample magnetometer. The results showed that the nanocomposites exhibited soft magnetism, with the mean diameter of 100 nm approximately. - Highlights: > Magnetic composites were prepared using {gamma}-Fe{sub 2}O{sub 3} and PS-b-PAA. > PS-b-PAA was synthesized by atom transfer radical polymerization. > The obtained composite exhibited soft magnetism.

Methods of analysis-Determination of pesticides in sediment using gas chromatography/mass spectrometry

Science.gov (United States)

Hladik, Michelle; McWayne, Megan M.

2012-01-01

A method for the determination of 119 pesticides in environmental sediment samples is described. The method was developed by the U.S. Geological Survey (USGS) in support of the National Water Quality Assessment (NAWQA) Program. The pesticides included in this method were chosen through prior prioritization. Herbicides, insecticides, and fungicides along with degradates are included in this method and span a variety of chemical classes including, but not limited to, chloroacetanilides, organochlorines, organophosphates, pyrethroids, triazines, and triazoles. Sediment samples are extracted by using an accelerated solvent extraction system (ASE®, and the compounds of interest are separated from co-extracted matrix interferences (including sulfur) by passing the extracts through high performance liquid chromatography (HPLC) with gel-permeation chromatography (GPC) along with the use of either stacked graphitized carbon and alumina solid-phase extraction (SPE) cartridges or packed Florisil®. Chromatographic separation, detection, and quantification of the pesticides from the sediment-sample extracts are done by using gas chromatography with mass spectrometry (GC/MS). Recoveries in test sediment samples fortified at 10 micrograms per kilogram (μg/kg) dry weight ranged from 75 to 102 percent; relative standard deviations ranged from 3 to 13 percent. Method detection limits (MDLs), calculated by using U.S. Environmental Protection Agency procedures (40 CFR 136, Appendix B), ranged from 0.6 to 3.4 μg/kg dry weight.

Permeation of a H2 + HD + D2 gas mixture through a polymer membrane

International Nuclear Information System (INIS)

Mercea, P.; Cuna, S.; Kreibik, S.; Ursu, I.

1990-01-01

The selective permeation of a H 2 + HD + D 2 gas mixture through a polyethylene terephthalate membrane was studied at T 20 0 C. It was found that the permeation of the HD through the membrane leads to a smaller overall hydrogen-deuterium separation factor than that determined in the permeation experiments with pure H 2 and D 2 . On the other hand, a process of isotopic exchange between deuterium atoms from the penetrant gas stream and hydrogen atoms from the polymer membrane is assumed and discussed in order to explain temporal variations of the H 2 , HD and D 2 concentrations of the permanent gas stream. (author)

Feasibility of permeation grouting for constructing subsurface barriers

International Nuclear Information System (INIS)

Dwyer, B.P.

1994-04-01

Efforts are being made to devise technologies that provide interim containment of waste sites while final remediation alternatives are developed. Permeation grouting, a technique used extensively in the civil and mining engineering industry has been investigated as a method for emplacing a subsurface containment barrier beneath existing waste sites. Conceptually an underlying barrier is placed by injecting grout into the formation at less than fracturing pressure from a series of directionally drilled boreholes beneath the waste site. This study evaluated the penetration and performance characteristics in varying soil conditions of four different grout materials (two microfine cements, mineral wax, and sodium silicate) at a field scale. Field testing consisted of grout injection via sleeve (tube-a'-manchette) pipe into both vertical and horizontal borehole configurations at the Mixed Waste Landfill Integrated Demonstration site at Sandia National Laboratories. Prior to, during, and after grout injection non-intrusive geophysical techniques were used to map grout flow. Following the tests, the site was excavated to reveal details of the grout permeation, and grouted soil samples were cored for laboratory characterization. The non-intrusive and intrusive grout mapping showed preferential flow patterns, i.e., the grout tended to follow the path of least resistance. Preliminary testing indicates that permeation grouting is a feasible method for emplacing a low permeability subsurface barrier in the semi-arid unconsolidated alluvial soils common to the Southwest. Despite the success of this project, difficulties in predicting grout flow in heterogeneous soils and non-intrusive methods for imaging grout location and continuity are issues that need more attention

Hydrogen permeation resistant heat pipe for bi-modal reactors. Final report, October 1, 1994--September 30, 1995

International Nuclear Information System (INIS)

North, M.T.; Anderson, W.G.

1995-01-01

The principal objective of this program was to demonstrate technology that will make a sodium heat pipe tolerant of hydrogen permeation for a bimodal space reactor application. Special focus was placed on techniques which enhance the permeation of hydrogen out of the heat pipe. Specific objectives include: define the detailed requirements for the bimodal reactor application; design and fabricate a prototype heat pipe tolerant of hydrogen permeation; and test the prototype heat pipe and demonstrate that hydrogen which permeates into the heat pipe is removed or reduced to acceptable levels. The results of the program were fully successful. Analyses were performed on two different heat pipe designs and an experimental heat pipe was fabricated and tested. A model of the experimental heat pipe was developed to predict the enhancement in the hydrogen permeation rate out of the heat pipe. A significant improvement in the rate at which hydrogen permeates out of a heat pipe was predicted for the use of the special condenser geometry developed here. Agreement between the model and the experimental results was qualitatively good. Inclusion of the additional effects of fluid flow in the heat pipe are recommended for future work

Effect of piperidones on hydrogen permeation and corrosion ...

Indian Academy of Sciences (India)

corrosion inhibition. 3.5 Hydrogen permeation measurements. Hydrogen can enter into the metal during various industrial operations like melting, heat treatment, or pickling and electrochemical processes such as cathodic cleaning and electrolytic machining. Of the various sources of entry of hydrogen into the metal,.

Thermogravimetric analysis of anthracite and waste plastics by iso-conversional method

International Nuclear Information System (INIS)

Ren, Shan; Zhang, Jianliang

2013-01-01

Highlights: • Co-combustion kinetic analysis of solid fuels was made by iso-conversional method. • Thermodynamic and kinetic parameters of combustion for blends were determined. • WP can improve the combustion characteristic of high ash anthracite. • Reasonable utilization the energy of WP is important for industrial production. - Abstract: Combustion mechanisms and kinetics of plastics-coal blends with 0, 10, 20, 40 and 100% waste plastics (WP) are studied separately by thermogravimetric analysis (TGA) from ambient temperature to 900 °C in air atmosphere. These blends are combusted at different heating rates. The results indicate that, with the increase of waste plastics content, the combustion processes of blends could be divided into one stage, two stages, three stages and one stage. Meanwhile, the ignition and final temperatures of them both decrease. The maximum weight loss rate of WP is much higher than that of other samples. The iso-conversional method is used for the kinetic analysis of the non-isothermal thermogravimetric data and results indicate that, when the waste plastics content varied from 0% to 40%, the values of activation energy increase from 113.3 kJ mol −1 to 156.0 kJ mol −1 , and the value of activation energy for pure WP is 278.8 kJ mol −1

In vitro permeation of palladium powders through intact and damaged human skin.

Science.gov (United States)

Crosera, Matteo; Mauro, Marcella; Bovenzi, Massimo; Adami, Gianpiero; Baracchini, Elena; Maina, Giovanni; Larese Filon, Francesca

2018-05-01

The use of palladium (Pd) has grown in the last decades, commonly used in automotive catalytic converters, jewellery and dental restorations sectors. Both general and working population can be exposed to this metal, which may act as skin sensitizer. This study investigated in vitro palladium powders permeation through excised intact and damaged human skin using the Franz diffusion cell method and the effect of rapid skin decontamination using sodium laureth-sulphate. 1 mL of a 10 min sonicated suspension made of 2.5 g of Pd powder in 50 mL synthetic sweat at pH 4.5 and room temperature was applied to the outer surface of the skin membranes for 24 h. Pd permeation, assessed by ICP-MS, was higher when damaged skin was used (p = 0.03). Final flux permeation values and lag times were 0.02 ± 0.01 μg cm -2  h -1 and 6.00 ± 3.95 h for intact, and 0.10 ± 0.02 μg cm -2  h -1 and 2.05 ± 1.49 h for damaged skin samples, respectively. Damaged skin protocol enhances Pd skin penetration inside dermal layer (p = 0.04), thus making the metal available for systemic uptake. Pd penetration (p = 0.02) and permeation (p = 0.012) through intact skin decreased significantly when a cleaning procedure was applied. This study demonstrates that after skin exposure to Pd powders a small permeation of the metal happen both through intact and damaged skin and that an early decontamination with a common cleanser can significantly decrease the final amount of metal available forsystemic uptake. Copyright © 2018 Elsevier B.V. All rights reserved.

Analysis of transient permeation behavior of hydrogen isotope caused by abrupt temperature change of first wall and blanket wall material

International Nuclear Information System (INIS)

Yamawaki, Michio; Tanaka, Satoru; Kiyoshi, Tsukasa

1989-01-01

To obtain further information on the transient permeation behavior of hydrogen isotopes as caused by an abrupt temperature change, numerical calculations were carried out for two typical metals, nickel and vanadium. Deuterium permeation through nickel is analyzed as a typical case of bulk-diffusion-limited permeation. Its transient behavior changed dramatically according to the specimen thickness. The transient behavior, in general, is separated into two parts, initial and latter period behaviors. Conditions which cause such a separation were evaluated. Evaluation of the hydrogen diffusivity and solubility by an analysis of transient curves of hydrogen permeation was carried out. The transient behavior of simultaneous gas- and ion-driven hydrogen permeation through vanadium was also analyzed. Overshooting of the hydrogen permeation rate appears with an abrupt temperature increase. Increasing the impinging ion flux causes the overshooting peak to become sharper, and also reduces the change of the steady-state permeation rate to be attained after the temperature change compared with the initial value. (orig.)

Ozonation of nanofiltration permeate of whey before processing by reverse osmosis

Directory of Open Access Journals (Sweden)

Zmievskii Yurii G.

2017-01-01

Full Text Available During nanofiltration processing of whey a significant amount of permeate is generated. In some cases this permeate is treated by reverse osmosis to get purified water for technological needs. Dry substances are not used, because they contain practically the same amount of organic and inorganic components. Mineral substances can be used for the mineralization of drinking water purified by reverse osmosis. However, the presence of organic compounds complicates the process of separation, as well as reduces the specific productivity of reverse osmosis membranes at the concentration stage. Therefore, the search for methods of destruction and removal of organic components is grounded. In the presented work, experimental studies of ozonation and sorption of organic compounds by activated carbon were carried. It has been shown that ozonation improves the degree of sorption purification by six times. Sequential treatment with ozone and subsequent filtration through the layer of activated carbon improves the specific productivity of reverse osmosis membranes by 30% at the stage of treatment of the nanofiltration permeate, while their selectivity remains unchanged.

Bias-Exchange Metadynamics Simulation of Membrane Permeation of 20 Amino Acids.

Science.gov (United States)

Cao, Zanxia; Bian, Yunqiang; Hu, Guodong; Zhao, Liling; Kong, Zhenzhen; Yang, Yuedong; Wang, Jihua; Zhou, Yaoqi

2018-03-16

Thermodynamics of the permeation of amino acids from water to lipid bilayers is an important first step for understanding the mechanism of cell-permeating peptides and the thermodynamics of membrane protein structure and stability. In this work, we employed bias-exchange metadynamics simulations to simulate the membrane permeation of all 20 amino acids from water to the center of a dipalmitoylphosphatidylcholine (DPPC) membrane (consists of 256 lipids) by using both directional and torsion angles for conformational sampling. The overall accuracy for the free energy profiles obtained is supported by significant correlation coefficients (correlation coefficient at 0.5-0.6) between our results and previous experimental or computational studies. The free energy profiles indicated that (1) polar amino acids have larger free energy barriers than nonpolar amino acids; (2) negatively charged amino acids are the most difficult to enter into the membrane; and (3) conformational transitions for many amino acids during membrane crossing is the key for reduced free energy barriers. These results represent the first set of simulated free energy profiles of membrane crossing for all 20 amino acids.

Bias-Exchange Metadynamics Simulation of Membrane Permeation of 20 Amino Acids

Directory of Open Access Journals (Sweden)

Zanxia Cao

2018-03-01

Full Text Available Thermodynamics of the permeation of amino acids from water to lipid bilayers is an important first step for understanding the mechanism of cell-permeating peptides and the thermodynamics of membrane protein structure and stability. In this work, we employed bias-exchange metadynamics simulations to simulate the membrane permeation of all 20 amino acids from water to the center of a dipalmitoylphosphatidylcholine (DPPC membrane (consists of 256 lipids by using both directional and torsion angles for conformational sampling. The overall accuracy for the free energy profiles obtained is supported by significant correlation coefficients (correlation coefficient at 0.5–0.6 between our results and previous experimental or computational studies. The free energy profiles indicated that (1 polar amino acids have larger free energy barriers than nonpolar amino acids; (2 negatively charged amino acids are the most difficult to enter into the membrane; and (3 conformational transitions for many amino acids during membrane crossing is the key for reduced free energy barriers. These results represent the first set of simulated free energy profiles of membrane crossing for all 20 amino acids.

Synthesis, characterization and thermogravimetric study of zinc and cadmium acetates-polyaniline hybrids

International Nuclear Information System (INIS)

Fernandes de Farias, Robson

2004-01-01

By dissolution of respective acetates and conducting polymer in dimethylformamide, homogeneous zinc acetate and cadmium acetate-polyaniline (PANI) hybrids were synthesized and characterized by infrared spectroscopy, thermogravimetry and SEM microscopy. The infrared spectra suggests that there are interactions between PANI and the metal cations involving both, imine and amine nitrogens in a typical Lewis acid-base reaction. The thermogravimetric degradation profile of the synthesized hybrids resembles those exhibited by PANI samples

Tritium permeation and recovery

International Nuclear Information System (INIS)

Bond, R.A.; Hamilton, A.M.

1987-01-01

The paper is an appendix to a study of the reactor relevance of the NET design concept. The latter study examines whether the technologies and design principles proposed for NET can be directly extrapolated to a demonstration (DEMO) reactor. In this appendix, tritium transport in the DEMO breeding blanket is considered with emphasis on the permeation rate from the lithium-lead breeder into the coolant. A computational model used to calculate the tritium transport in the breeder blanket is described. Results are reported for the tritium transport in the NET/INTOR type blanket as well as the DEMO blanket in order to provide a comparison. In addition, results are presented for the helium coolant tritium extraction analysis. (U.K.)

Experimental measurements of the permeation of hydrogen isotopes in lithium filled niobium cells

International Nuclear Information System (INIS)

Goodall, D.H.J.; McCracken, G.M.; Austin, G.E.

1976-01-01

Lithium filled niobium cells have been heated in vacua at temperatures in the range 300 to 900 0 C. By measuring the flow of deuterium into the cell it has been possible to make estimates of the rate of permeation of deuterium in the niobium wall. After initial fast diffusion into the capsule the rate of permeation becomes very much slower than that determined by diffusion in the bulk niobium indicating that a second, slower, rate process is involved. Measurements of the rate of deuterium permeation out of the cell have been made for a number of different cell geometries and a range of temperatures. The results indicate that the slow rate process, which is dominant at low concentrations, is the desorption step from the metal to the gas phase

Comparing pervaporation and vapor permeation hybrid distillation processes

NARCIS (Netherlands)

Fontalvo, J.; Cuellar, P.; Timmer, J.M.K.; Vorstman, M.A.G.; Wijers, J.G.; Keurentjes, J.T.F.

2005-01-01

Previous studies have shown that hybrid distillation processes using either pervaporation or vapor permeation can be very attractive for the separation of mixtures. In this paper, a comparison between these two hybrid processes has been made. A tool has been presented that can assist designers and

40 CFR 1051.515 - How do I test my fuel tank for permeation emissions?

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false How do I test my fuel tank for... Procedures § 1051.515 How do I test my fuel tank for permeation emissions? Measure permeation emissions by weighing a sealed fuel tank before and after a temperature-controlled soak. (a) Preconditioning fuel soak...

Recommendations for plutonium colloid size determination

International Nuclear Information System (INIS)

Kosiewicz, S.T.

1984-02-01

This report presents recommendations for plutonium colloid size determination and summarizes a literature review, discussions with other researchers, and comments from equipment manufacturers. Four techniques suitable for plutonium colloid size characterization are filtration and ultrafiltration, gel permeation chromatography, diffusion methods, and high-pressure liquid chromatography (conditionally). Our findings include the following: (1) Filtration and ultrafiltration should be the first methods used for plutonium colloid size determination because they can provide the most rapid results with the least complicated experimental arrangement. (2) After expertise has been obtained with filtering, gel permeation chromatography should be incorporated into the colloid size determination program. (3) Diffusion methods can be used next. (4) High-pressure liquid chromatography will be suitable after appropriate columns are available. A plutonium colloid size characterization program with filtration/ultrafiltration and gel permeation chromatography has been initiated

Thermogravimetric analysis coupled with chemometrics as a powerful predictive tool for ß-thalassemia screening.

Science.gov (United States)

Risoluti, Roberta; Materazzi, Stefano; Sorrentino, Francesco; Maffei, Laura; Caprari, Patrizia

2016-10-01

β-Thalassemia is a hemoglobin genetic disorder characterized by the absence or reduced β-globin chain synthesis, one of the constituents of the adult hemoglobin tetramer. In this study the possibility of using thermogravimetric analysis (TGA) followed by chemometrics as a new approach for β-thalassemia detection is proposed. Blood samples from patients with β-thalassemia were analyzed by the TG7 thermobalance and the resulting curves were compared to those typical of healthy individuals. Principal Component Analysis (PCA) was used to evaluate the correlation between the hematological parameters and the thermogravimetric results. The thermogravimetric profiles of blood samples from β-thalassemia patients were clearly distinct from those of healthy individuals as result of the different quantities of water content and corpuscular fraction. The hematological overview showed significant decreases in the values of red blood cell indices and an increase in red cell distribution width value in thalassemia subjects when compared with those of healthy subjects. The implementation of a predictive model based on Partial Least Square Discriminant Analysis (PLS-DA) for β-thalassemia diagnosis, was performed and validated. This model permitted the discrimination of anemic patients and healthy individuals and was able to detect thalassemia in clinically heterogeneous patients as in the presence of δβ-thalassemia and β-thalassemia combined with Hb Lepore. TGA and Chemometrics are capable of predicting ß-thalassemia syndromes using only a few microliters of blood without any pretreatment and with an hour of analysis time. A fast, rapid and cost-effective diagnostic tool for the β-thalassemia screening is proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

Fully automatic flow-based device for monitoring of drug permeation across a cell monolayer.

Science.gov (United States)

Zelená, Lucie; Marques, Sara S; Segundo, Marcela A; Miró, Manuel; Pávek, Petr; Sklenářová, Hana; Solich, Petr

2016-01-01

A novel flow-programming setup based on the sequential injection principle is herein proposed for on-line monitoring of temporal events in cell permeation studies. The permeation unit consists of a Franz cell with its basolateral compartment mixed under mechanical agitation and thermostated at 37 °C. The apical compartment is replaced by commercially available Transwell inserts with a precultivated cell monolayer. The transport of drug substances across epithelial cells genetically modified with the P-glycoprotein membrane transporter (MDCKII-MDR1) is monitored on-line using rhodamine 123 as a fluorescent marker. The permeation kinetics of the marker is obtained in a fully automated mode by sampling minute volumes of solution from the basolateral compartment in short intervals (10 min) up to 4 h. The effect of a P-glycoprotein transporter inhibitor, verapamil as a model drug, on the efficiency of the marker transport across the cell monolayer is thoroughly investigated. The analytical features of the proposed flow method for cell permeation studies in real time are critically compared against conventional batch-wise procedures and microfluidic devices.

Chromatography.

Science.gov (United States)

Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

This booklet presents some activities on chromatography. Directions for preparing leaf pigment extracts using alcohol are given, and paper chromatography and thin-layer chromatography are described as modifications of the basic principles of chromatography. (KHR)

Impact of Humidity on In Vitro Human Skin Permeation Experiments for Predicting In Vivo Permeability.

Science.gov (United States)

Ishida, Masahiro; Takeuchi, Hiroyuki; Endo, Hiromi; Yamaguchi, Jun-Ichi

2015-12-01

In vitro skin permeation studies have been commonly conducted to predict in vivo permeability for the development of transdermal therapeutic systems (TTSs). We clarified the impact of humidity on in vitro human skin permeation of two TTSs having different breathability and then elucidated the predictability of in vivo permeability based on in vitro experimental data. Nicotinell(®) TTS(®) 20 and Frandol(®) tape 40mg were used as model TTSs in this study. The in vitro human skin permeation experiments were conducted under humidity levels similar to those used in clinical trials (approximately 50%) as well as under higher humidity levels (approximately 95%). The skin permeability values of drugs at 95% humidity were higher than those at 50% humidity. The time profiles of the human plasma concentrations after TTS application fitted well with the clinical data when predicted based on the in vitro permeation parameters at 50% humidity. On the other hand, those profiles predicted based on the parameters at 95% humidity were overestimated. The impact of humidity was higher for the more breathable TTS; Frandol(®) tape 40mg. These results show that in vitro human skin permeation experiments should be investigated under realistic clinical humidity levels especially for breathable TTSs. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

d-Tagatose production by permeabilized and immobilized Lactobacillus plantarum using whey permeate.

Science.gov (United States)

Jayamuthunagai, J; Srisowmeya, G; Chakravarthy, M; Gautam, P

2017-07-01

The aim of the work is to produce d-Tagatose by direct addition of alginate immobilized Lactobacillus plantarum cells to lactose hydrolysed whey permeate. The cells were untreated and immobilized (UIC), permeabilized and immobilized (PIC) and the relative activities were compared with purified l-arabinose isomerase (l-AI) for d-galactose isomerization. Successive lactose hydrolysis by β-galactosidase from Escherichia coli and d-galactose isomerization using l-AI from Lactobacillus plantarum was performed to investigate the in vivo production of d-tagatose in whey permeate. In whey permeate, maximum conversion of 38% and 33% (w/w) d-galactose isomerization by PIC and UIC has been obtained. 162mg/g and 141mg/g of d-tagatose production was recorded in a 48h reaction time at 50°C, pH 7.0 with 5mM Mn 2+ ion concentration in the initial substrate mixture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of nanoparticle surface coatings and nanoparticle purity using microscale thermogravimetric analysis.

Science.gov (United States)

Mansfield, Elisabeth; Tyner, Katherine M; Poling, Christopher M; Blacklock, Jenifer L

2014-02-04

The use of nanoparticles in some applications (i.e., nanomedical, nanofiltration, or nanoelectronic) requires small samples with well-known purities and composition. In addition, when nanoparticles are introduced into complex environments (e.g., biological fluids), the particles may become coated with matter, such as proteins or lipid layers. Many of today's analytical techniques are not able to address small-scale samples of nanoparticles to determine purity and the presence of surface coatings. Through the use of an elevated-temperature quartz crystal microbalance (QCM) method we call microscale thermogravimetric analysis, or μ-TGA, the nanoparticle purity, as well as the presence of any surface coatings of nanomaterials, can be measured. Microscale thermogravimetric analysis is used to determine the presence and amount of surface-bound ligand coverage on gold nanoparticles and confirm the presence of a poly(ethylene glycol) coating on SiO2 nanoparticles. Results are compared to traditional analytical techniques to demonstrate reproducibility and validity of μ-TGA for determining the presence of nanoparticle surface coatings. Carbon nanotube samples are also analyzed and compared to conventional TGA. The results demonstrate μ-TGA is a valid method for quantitative determination of the coatings on nanoparticles, and in some cases, can provide purity and compositional data of the nanoparticles themselves.

Transdermal delivery of diclofenac using water-in-oil microemulsion: formulation and mechanistic approach of drug skin permeation.

Science.gov (United States)

Thakkar, Priyanka J; Madan, Parshotam; Lin, Senshang

2014-05-01

The objective of the present investigation was to enhance skin permeation of diclofenac using water-in-oil microemulsion and to elucidate its skin permeation mechanism. The w/o microemulsion formulations were selected based on constructed pseudoternary phase diagrams depending on water solubilization capacity and thermodynamic stability. These formulations were also subjected to physical characterization based on droplet size, viscosity, pH and conductivity. Permeation of diclofenac across rat skin using side-by-side permeation cells from selected w/o microemulsion formulations were evaluated and compared with control formulations. The selected w/o microemulsion formulations were thermodynamically stable, and incorporation of diclofenac sodium into microemulsion did not affect the phase behavior of system. All microemulsion formulations had very low viscosity (11-17 cps) and droplet size range of 30-160 nm. Microemulsion formulations exhibited statistically significant increase in diclofenac permeation compared to oily solution, aqueous solution and oil-Smix solution. Higher skin permeation of diclofenac was observed with low Smix concentration and smaller droplet size. Increase in diclofenac loading in aqueous phase decreased the partition of diclofenac. Diclofenac from the oil phase of microemulsion could directly partition into skin, while diclofenac from the aqueous droplets was carried through skin by carrier effect.

Permeation of antigen protein-conjugated nanoparticles and live bacteria through microneedle-treated mouse skin

Directory of Open Access Journals (Sweden)

Kumar A

2011-06-01

Full Text Available Amit Kumar, Xinran Li, Michael A Sandoval, B Leticia Rodriguez, Brian R Sloat, Zhengrong CuiUniversity of Texas at Austin, College of Pharmacy, Pharmaceutics Division, Austin, TX, USABackground: The present study was designed to evaluate the extent to which pretreatment with microneedles can enhance skin permeation of nanoparticles in vitro and in vivo. Permeation of live bacteria, which are physically nanoparticles or microparticles, through mouse skin pretreated with microneedles was also studied to evaluate the potential risk of microbial infection.Methods and results: It was found that pretreatment of mouse skin with microneedles allowed permeation of solid lipid nanoparticles, size 230 nm, with ovalbumin conjugated on their surface. Transcutaneous immunization in a mouse skin area pretreated with microneedles with ovalbumin nanoparticles induced a stronger antiovalbumin antibody response than using ovalbumin alone. The dose of ovalbumin antigen determined whether microneedle-mediated transcutaneous immunization with ovalbumin nanoparticles induced a stronger immune response than subcutaneous injection of the same ovalbumin nanoparticles. Microneedle treatment permitted skin permeation of live Escherichia coli, but the extent of the permeation was not greater than that enabled by hypodermic injection.Conclusion: Transcutaneous immunization on a microneedle-treated skin area with antigens carried by nanoparticles can potentially induce a strong immune response, and the risk of bacterial infection associated with microneedle treatment is no greater than that with a hypodermic injection.Keywords: antibody responses, safety of microneedles, transepidermal water loss

Transcriptome and membrane fatty acid analyses reveal different strategies for responding to permeating and non-permeating solutes in the bacterium Sphingomonas wittichii

Directory of Open Access Journals (Sweden)

Johnson David R

2011-11-01

Full Text Available Abstract Background Sphingomonas wittichii strain RW1 can completely oxidize dibenzo-p-dioxins and dibenzofurans, which are persistent contaminants of soils and sediments. For successful application in soil bioremediation systems, strain RW1 must cope with fluctuations in water availability, or water potential. Thus far, however, little is known about the adaptive strategies used by Sphingomonas bacteria to respond to changes in water potential. To improve our understanding, strain RW1 was perturbed with either the cell-permeating solute sodium chloride or the non-permeating solute polyethylene glycol with a molecular weight of 8000 (PEG8000. These solutes are assumed to simulate the solute and matric components of the total water potential, respectively. The responses to these perturbations were then assessed and compared using a combination of growth assays, transcriptome profiling, and membrane fatty acid analyses. Results Under conditions producing a similar decrease in water potential but without effect on growth rate, there was only a limited shared response to perturbation with sodium chloride or PEG8000. This shared response included the increased expression of genes involved with trehalose and exopolysaccharide biosynthesis and the reduced expression of genes involved with flagella biosynthesis. Mostly, the responses to perturbation with sodium chloride or PEG8000 were very different. Only sodium chloride triggered the increased expression of two ECF-type RNA polymerase sigma factors and the differential expression of many genes involved with outer membrane and amino acid metabolism. In contrast, only PEG8000 triggered the increased expression of a heat shock-type RNA polymerase sigma factor along with many genes involved with protein turnover and repair. Membrane fatty acid analyses further corroborated these differences. The degree of saturation of membrane fatty acids increased after perturbation with sodium chloride but had the

Effect of Microneedle Type on Transdermal Permeation of Rizatriptan.

Science.gov (United States)

Uppuluri, Chandrateja; Shaik, Ashraf Sultana; Han, Tao; Nayak, Atul; Nair, Karthik J; Whiteside, Benjamin R; Nalluri, Buchi N; Das, Diganta B

2017-07-01

The present study was aimed to investigate the effect of salient microneedle (MN) geometry parameters like length, density, shape and type on transdermal permeation of rizatriptan (RIZ). Studies were carried out using two types of MN devices viz. AdminPatch® arrays (ADM) (0.6, 0.9, 1.2 and 1.5 mm lengths) and laboratory-fabricated polymeric MNs (PMs) of 0.6 mm length. In the case of the PMs, arrays were applied three times at different places within a 1.77-cm 2 skin area (PM-3) to maintain the MN density closer to 0.6 mm ADM. Histological studies revealed that PM, owing to their geometry/design, formed wider and deeper microconduits when compared to ADM of similar length. Approximately 4.9- and 4.2-fold increases in the RIZ steady-state flux values were observed with 1.5 mm ADM and PM-3 applications when compared to the passive studies. A good correlation between different dimensionless parameters like the amount of RIZ permeated (C t /C s ), thickness (h/L) and surface area (S a /L 2 ) of the skin was observed with scaling analyses. Numerical simulations provided further information regarding the distribution of RIZ in MN-treated skin after application of different MNs. Overall, the study suggests that MN application enhances the RIZ transdermal permeation and the geometrical parameters of MNs play an important role in the degree enhancement.

Study on low temperature plasma driven permeation of hydrogen

Energy Technology Data Exchange (ETDEWEB)

Takizawa, Masayuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-03-01

It is one of the most important problem in PWI of fusion devices from the point of view of tritium leakage that hydrogen diffuses in the wall of the device and permeates through it, which results in hydrogen being released to the coolant side. In this study, plasma driven permeation experiments were carried out with several kinds of metal membranes in the low temperature plasma where ionic and atomic hydrogen as well as electron existed in order to survey PDP mechanism from the many view points. In addition, incident flux rate from the plasma to the membrane surface was evaluated by calculation analysis. As a result the mechanism of low temperature PDP was found out and described as PDP models. The simulation of the membrane pump system was executed and the system performance was estimated with the models. (author). 135 refs.

Study on low temperature plasma driven permeation of hydrogen

International Nuclear Information System (INIS)

Takizawa, Masayuki

1998-03-01

It is one of the most important problem in PWI of fusion devices from the point of view of tritium leakage that hydrogen diffuses in the wall of the device and permeates through it, which results in hydrogen being released to the coolant side. In this study, plasma driven permeation experiments were carried out with several kinds of metal membranes in the low temperature plasma where ionic and atomic hydrogen as well as electron existed in order to survey PDP mechanism from the many view points. In addition, incident flux rate from the plasma to the membrane surface was evaluated by calculation analysis. As a result the mechanism of low temperature PDP was found out and described as PDP models. The simulation of the membrane pump system was executed and the system performance was estimated with the models. (author). 135 refs

Investigation of non-magnetic alloys for the suppression of tritium permeation. Final report

International Nuclear Information System (INIS)

1980-07-01

This report describes a small (300 man hour) literature survey relating to the suppression of tritium loss by permeation through the walls of fusion reactors. The program was based on prior in-house Thermacore work to suppress hydrogen permeation into high temperature (800 0 C) heat pipes. The Thermacore approach involves selection of a steel with a small (.5 to 5%) aluminum content. The aluminum is diffused to the surface and oxidized. The present work was aimed at identification of alloys which might combine low tritium permeation with other properties desired in fusion reactor vessels, heat exchangers, lithium-handling plumbing and other components likely to contain tritium. These properties include low radiation damage, low magnetic permeability, high temperature strength, and compatibility with potential heat transfer and blanket materials. The work consisted of two tasks: Problem Definition and Literature Search and Analysis

Physics-Based Modeling of Permeation: Simulation of Low-Volatility Agent Permeation and Aerosol Vapor Liquid Assessment Group Experiments

Science.gov (United States)

2015-06-01

methylphosphonothiolate (VX) through natural latex rubber and neoprene resulting from LVAP tests. 2. The permeation model is used to study the sensitivity of...Styrene–Butadiene– Rubber , Ethylene–Propylene–Diene Terpolymer, and Natural Rubber Versus Hydrocarbons (C8–C16). Macromolecules 1991, 24 (9), 2598–2605...22 14. Harogoppad, S.B.; Aminabhavi, T.M. Diffusion and Sorption of Organic Liquids through Polymer Membranes 2. Neoprene, SBR, EPDM, NBR , and

The ‘ideal selectivity’ vs ‘true selectivity’ for permeation of gas mixture in nanoporous membranes

Science.gov (United States)

He, Zhou; Wang, Kean

2018-03-01

In this study, we proposed and validated a novel and non-destructive experimental technology for measuring the permeation of binary gas mixture in nanoporous membranes. The traditional time lag rig was modified to examine the permeation characteristics of each gas component as well as that of the binary gas mixtures. The difference in boiling points of each species were explored. Binary gas mixtures of CO2/He were permeated through the nanoporous carbon molecular sieve membrane (CMSM). The results showed that, due to the strong interaction among different molecules and with the porous network of the membrane, the measured perm-selectivity or ‘true selectivity’ of a binary mixture can significantly deviate from the ‘ideal selectivity’ calculated form the permeation flux of each pure species, and this deviation is a complicated function of the molecular properties and operation conditions.

Phase Change Permeation Technology for Environmental Control & Life Support Systems

Data.gov (United States)

National Aeronautics and Space Administration — NASA is evaluating Dutyion™, a phase change permeation membrane technology developed by Design Technology and Irrigation (DTI), for use in future advanced life...

PermeaLoop™, a novel in vitro tool for small-scale drug-dissolution/permeation studies

DEFF Research Database (Denmark)

Sironi, Daniel; Rosenberg, Jörg; Bauer-Brandl, Annette

2018-01-01

dissolution and permeation, as it is occurring in vivo. We propose a novel setup with a high area-to-volume ratio and report as a model case the dissolution/permeation behavior of an enabling formulation of the poorly soluble and poorly permeable drug ABT-869. Mini tablets consisting of an amorphous solid......Loop™ is regarded a promising tool for evaluating enabling formulations....

Investigation on the suitability of plasma sprayed Fe-Cr-Al coatings as tritium permeation barrier

International Nuclear Information System (INIS)

Fazio, C.; Serra, E.; Benamati, G.

1999-01-01

Results on the fabrication of a tritium permeation barrier by spraying Fe-Cr-Al powders are described. The sprayed coatings were deposited at temperatures below the A c1 temperature of the ferritic-martensitic steel substrate and no post-deposition heat treatment was applied. The aim of the investigation was the determination of the efficiency of the coatings to act as tritium permeation barrier. Metallurgical investigations as well as hydrogen isotope permeation measurements were carried out onto the produced coatings. The depositions were performed on ferritic-martensitic steels by means of three types of spray techniques: high velocity oxy fuel, air plasma spray and vacuum plasma spray. (orig.)

Liquid and Gas Permeation Studies on the Structure and Properties of Polyamide Thin-Film Composite Membranes

KAUST Repository

Duan, Jintang

2014-01-01

layer by gas adsorption and gas permeation measurements. Gas adsorption isotherms (N2 at 77K, CO2 at 273K) confirmed the microporous nature of PA in comparison with dense CTA and polysulfone materials. Gas permeation through the commercial PA

Implanted-tritium permeation experiments

International Nuclear Information System (INIS)

Longhurst, G.R.; Holland, D.F.; Casper, L.A.; Hsu, P.Y.; Miller, L.G.; Schmunk, R.E.; Watts, K.D.; Wilson, C.J.; Kershner, C.J.; Rogers, M.L.

1982-04-01

In fusion reactors, charge exchange neutral atoms of tritium coming from the plasma will be implanted into the first wall and other interior structures. EG and G Idaho is conducting two experiments to determine the magnitude of permeation into the coolant streams and the retention of tritium in those structures. One experiment uses an ion gun to implant deuterium. The ion gun will permit measurements to be made for a variety of implantation energies and fluxes. The second experiment utilizes a fission reactor to generate a tritium implantation flux by the 3 He(n,p) 3 H reaction. This experiment will simulate the fusion reactor radiation environment. We also plan to verify a supporting analytical code development program, in progress, by these experiments

Hydrogen permeation in FeCrAl alloys for LWR cladding application

Science.gov (United States)

Hu, Xunxiang; Terrani, Kurt A.; Wirth, Brian D.; Snead, Lance L.

2015-06-01

FeCrAl, an advanced oxidation-resistant iron-based alloy class, is a highly prevalent candidate as an accident-tolerant fuel cladding material. Compared with traditional zirconium alloy fuel cladding, increased tritium permeation through FeCrAl fuel cladding to the primary coolant is expected, raising potential safety concerns. In this study, the hydrogen permeability of several FeCrAl alloys was obtained using a static permeation test station, which was calibrated and validated using 304 stainless steel. The high hydrogen permeability of FeCrAl alloys leads to concerns with respect to potentially significant tritium release when used for fuel cladding in LWRs. The total tritium inventory inside the primary coolant of a light water reactor was quantified by applying a 1-dimensional steady state tritium diffusion model to demonstrate the dependence of tritium inventory on fuel cladding type. Furthermore, potential mitigation strategies for tritium release from FeCrAl fuel cladding were discussed and indicate the potential for application of an alumina layer on the inner clad surface to serve as a tritium barrier. More effort is required to develop a robust, economical mitigation strategy for tritium permeation in reactors using FeCrAl clad fuel assemblies.

Dynamic permeation sources for volatile organic compounds (VOCS): 'a standards test environment' nuclear track detector

International Nuclear Information System (INIS)

Hussain, A.; Marr, I.

2000-01-01

The generation of a test environment for trace VOCs in urban air or work place has never been easy. This investigation is concerned with the loss rates of VOCs through polythene membrane of different thickness. Permeation glass sample bottles were suspended in the chamber with water jacket at 24 deg. C -+ 0.5 deg. temperature. The condenser was connected with a stream of nitrogen gas at a flow rate of 75-ml min/sup -1 and further diluted with air 500-ml min/sup -1/. The loss in weight of VOCs in each bottle was determined regularly, every 24 hours, with a good agreement. The loss rate depends upon temperature of the bath, thickness of the polythene, internal diameter of the permeation bottle opening. However the loss rate from permeation tubes also depends upon the solubility of the VOCs in the polymer. It is generally believed that the vapors of VOCs in the permeation bottle are dissolved in the polythene sheet (making some sort of solution) and are eventually evaporated out of it. It was observed that the loss rate per minute for benzene > toluene. This simple technique described 'generation of test environment through dynamic permeation source' could be suitable for preparing mixture of benzene, toluene and xylene in atmosphere at ppm levels or lower, with good stability, reliability and also for other compounds of atmospheric interest. (author)

Permeation of Mixed Penetrants through Glassy Polymer Membranes.

Science.gov (United States)

1985-03-15

and LOPE. Also, ESCA was used in conjunction with plasma etching to determine the effects of the gas phase fluorine concentration and fluorination...at 35 3C. ARD-AISS5 65 PERMEATION OF MIXED PENETRANTS THROUGH GLASSY POLYMER 213 MENBRANES (U) NORTH CAROLINA STATE UNIV AT RALEIGH R T CHERN ET AL. 15

Investigation on hydrogen permeation on heat exchanger materials in conditions of steam coal gasification

International Nuclear Information System (INIS)

Moellenhoff, H.

1984-01-01

The permeation of hydrogen through iron-based alloys of different compositions in the temperature range between 700 and 1000 0 C was examined in a laboratory fluidized bed in the conditions of steam/coal gasification. Apart from tests on bright metal samples, measurement in the gasification atmosphere at a maximum pressure of 1 bar were carried out during oxidation of the metal. Experiments in a steam/hydrogen/argon mixture with the same oxidation potential were used for comparison purposes. The hydrogen permeated through the metal sample was taken to a gas chromatograph with argon flushing gas and analyzed there. The investigations on bright steel samples of various composition showed that their permeabilities for hydrogen at temperatures around 900 0 C only differed by a maximum of ± 30%. Effective prevention of permeation is therefore not possible simply by choosing a suitable alloy. If the steels are oxidized during permeation measurements, there is a reduction of the hydrogen permeability by 2 or 3 orders of magnitude due to the oxidation process, both in the steam/coal gasification fluidized bed and in a pure steam/hydrogen/argon mixture. (orig./GG) [de

Thermogravimetric study of the reaction of uranium oxides with fluorine

International Nuclear Information System (INIS)

Komura, Motohiro; Sato, Nobuaki; Kirishima, Akira; Tochiyama, Osamu

2008-01-01

Thermogravimetric study of the reaction of uranium oxides with fluorine was conducted by TG-DTA method using anti-corrosion type differential thermobalance. When UO 2 was heated from R.T. to 500 deg. C in 5% F 2 /He atmosphere, the weight increase appeared at ca. 250 deg. C with an exothermic peak. Then the weight decreased slightly with a small exothermic peak followed by the complete volatilization with a large exothermic peak at ca. 350 deg. C. At a flow rate of 15, 30, 60 ml min -1 , there seemed to be no significant change for the fluorination of UO 2 . With the different heating rates of 1, 2, 5 and 10 deg. C min -1 , the fluorination peak shifted to higher temperature with increasing heating rates. For the comparison with thermogravimetric results, phase analysis by XRD method was conducted for the products obtained at different temperatures. At 260 deg. C, the product was UO 2 with a small amount of the intermediate compound, UO 2 F. The amount of this compound increased with increasing temperature up to 320 deg. C. Then another phase of UO 2 F 2 appeared at 340 deg. C but it was immediately fluorinated to the volatile fluoride. When U 3 O 8 was used as a starting material, it was found that the steep weight decrease peak appeared at ca. 350 deg. C and the uranium volatilized completely. This result suggests that fluorination of U 3 O 8 occurs at this temperature forming UF 6 . Uranium trioxide showed the similar fluorination behavior to that of U 3 O 8

Development of Acyclovir-Loaded Albumin Nanoparticles and Improvement of Acyclovir Permeation Across Human Corneal Epithelial T Cells.

Science.gov (United States)

Suwannoi, Panita; Chomnawang, Mullika; Sarisuta, Narong; Reichl, Stephan; Müller-Goymann, Christel C

2017-12-01

The aim of the present study was to develop acyclovir (ACV) ocular drug delivery systems of bovine serum albumin (BSA) nanoparticles as well as to assess their in vitro transcorneal permeation across human corneal epithelial (HCE-T) cell multilayers. The ACV-loaded BSA nanoparticles were prepared by desolvation method along with physicochemical characterization, cytotoxicity, as well as in vitro transcorneal permeation studies across HCE-T cell multilayers. The nanoparticles appeared to be spherical in shape and nearly uniform in size of about 200 nm. The size of nanoparticles became smaller with decreasing BSA concentration, while the ratios of water to ethanol seemed not to affect the size. Increasing the amount of ethanol in desolvation process led to significant reduction of drug entrapment of nanoparticles with smaller size and more uniformity. The ACV-loaded BSA nanoparticles prepared were shown to have no cytotoxic effect on HCE-T cells used in permeation studies. The in vitro transcorneal permeation results revealed that ACV could permeate through the HCE-T cell multilayers significantly higher from BSA nanoparticles than from aqueous ACV solutions. The ACV-loaded BSA nanoparticles could be prepared by desolvation method without glutaraldehyde in the formulation. ACV could increasingly permeate through the multilayers of HCE-T cells from the ACV-loaded BSA nanoparticles. Therefore, the ACV-loaded BSA nanoparticles could be a highly potential ocular drug delivery system.

Permeation mechanisms of pulsed microwave plasma deposited silicon oxide films for food packaging applications

International Nuclear Information System (INIS)

Deilmann, Michael; Grabowski, Mirko; Theiss, Sebastian; Bibinov, Nikita; Awakowicz, Peter

2008-01-01

Silicon oxide barrier layers are deposited on polyethylene terephthalate as permeation barriers for food packaging applications by means of a low pressure microwave plasma. Hexamethyldisiloxane (HMDSO) and oxygen are used as process gases to deposit SiO x coatings via pulsed low pressure plasmas. The layer composition of the coating is investigated by Fourier transform infrared spectroscopy and energy dispersive x-ray spectroscopy to show correlations with barrier properties of the films. The oxygen permeation barrier is determined by the carrier gas method using an electrochemical detector. The transition from low to high barrier films is mapped by the transition from organic SiO x C y H z layers to quartz-like SiO 1.7 films containing silanol bound hydrogen. A residual permeation as low as J = 1 ± 0.3 cm 3 m -2 day -1 bar -1 is achieved, which is a good value for food packaging applications. Additionally, the activation energy E p of oxygen permeation is analysed and a strong increase from E p = 31.5 kJ mol -1 for SiO x C y H z -like coatings to E p = 53.7 kJ mol -1 for SiO 1.7 films is observed by increasing the oxygen dilution of HMDSO:O 2 plasma. The reason for the residual permeation of high barrier films is discussed and coating defects are visualized by capacitively coupled atomic oxygen plasma etching of coated substrates. A defect density of 3000 mm -2 is revealed

Effects of thin films on inventory, permeation and re-emission of energetic hydrogen

International Nuclear Information System (INIS)

Ohyabu, N.; Nakamura, Y.; Nakahara, Y.; Livshits, A.; Alimov, V.; Busnyuk, A.; Notkin, M.; Samartsev, A.; Doroshin, A.

2000-01-01

A non-metallic coating thicker than the implantation depth may protect a metal against tritium retention and permeation. However, a thinner film has quite the opposite effect: a dramatic increase of permeation and retention, and a corresponding suppression of re-emission. In view of the benefits expected from particle control with a superpermeable membrane placed right inside the divertor, the behavior of a Nb sample was investigated in a plasma-membrane device having a graphite target. Even polyatomic carbide coating was found not to hinder hydrogen absorption and permeation. Polyatomic non-carbide C films effectively inhibits it, but the formation of such films depends on H and C fluxes, H energy and metal temperature. A durable isolation of suprathermal hydrogen with the superpermeable membrane was observed at a high enough ratio between H and C fluxes, and the effects of carbon were found to have a non-monotonic temperature dependence

GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)

Science.gov (United States)

AbstractThe need for the development of polymeric materials based on renewable resources has led to the development of poly(lactic acid) (PLA) which is being produced from a feedstock of corn rather than petroleum. The present study examines the permeation of nitrogen...

Hydrogen permeation measurement of the reduced activation ferritic steel F82H by the vacuum thermo-balance method

International Nuclear Information System (INIS)

Yoshida, Hajime; Enoeda, Mikio; Abe, Tetsuya; Akiba, Masato

2005-03-01

Hydrogen permeation fluxes of the reduced activation ferritic steel F82H were quantitatively measured by a newly proposed method, vacuum thermo-balance method, for a precise estimation of tritium leakage in a fusion reactor. We prepared sample capsules made of F82H, which enclosed hydrogen gas. The hydrogen in the capsules permeated through the capsule wall, and subsequently desorbed from the capsule surface during isothermal heating. The vacuum thermo-balance method allows simultaneous measurement of the hydrogen permeation flux by two independent methods, namely, the net weight reduction of the sample capsule and exhaust gas analysis. Thus the simultaneous measurements by two independent methods increase the reliability of the permeability measurement. When the gas pressure of enclosed hydrogen was 0.8 atm at the sample temperature of 673 K, the hydrogen permeation flux of F82H obtained by the net weight reduction and the exhaust gas analysis was 0.75x10 18 (H 2 /m 2 s) and 2.2x10 18 (H 2 /m 2 s), respectively. The ratio of the hydrogen permeation fluxes obtained by the net weight reduction to that measured by the exhaust gas analysis was in the range from 1/4 to 1/1 in this experiment. The temperature dependence of the estimated permeation flux was similar in both methods. Taking the uncertainties of both measurements into consideration, both results are supposed to be consistent. The enhancement of hydrogen permeation flux was observed from the sample of which outer surface was mechanically polished. Through the present experiments, it has been demonstrated that the vacuum thermo-balance method is effective for the measurement of hydrogen permeation rate of F82H. (author)

Structural and functional significance of water permeation through cotransporters

DEFF Research Database (Denmark)

Zeuthen, Thomas; Gorraitz, Edurne; Her, Ka

2016-01-01

Membrane transporters, in addition to their major role as specific carriers for ions and small molecules, can also behave as water channels. However, neither the location of the water pathway in the protein nor their functional importance is known. Here, we map the pathway for water and urea...... through the intestinal sodium/glucose cotransporter SGLT1. Molecular dynamics simulations using the atomic structure of the bacterial transporter vSGLT suggest that water permeates the same path as Na+ and sugar. On a structural model of SGLT1, based on the homology structure of vSGLT, we identified...... to be due to alterations in steric hindrance to water and urea, and/or changes in protein folding caused by mismatching of side chains in the water pathway. Water permeation through SGLT1 and other transporters bears directly on the structural mechanism for the transport of polar solutes through...

Alfuzosin hydrochloride transdermal films: evaluation of physicochemical, in vitro human cadaver skin permeation and thermodynamic parameters

Directory of Open Access Journals (Sweden)

Satyanarayan Pattnaik

2009-12-01

Full Text Available Purpose: The main objective of the investigation was to develop a transdermal therapeutic system for alfuzosin hydrochloride and to study the effects of polymeric system and loading dose on the in vitro skin permeation pattern. Materials and methods: Principles of experimental design have been exploited to develop the dosage form. Ratio of ethyl cellulose (EC and polyvinyl pyrrolidone (PVP and loading dose were selected as independent variables and their influence on the cumulative amount of alfuzosin hydrochloride permeated per cm2 of human cadaver skin at 24 h (Q24, permeation flux (J and steady state permeability coefficient (P SS were studied using experimental design. Various physicochemical parameters of the transdermal films were also evaluated. Activation energy for in vitro transdermal permeation has been estimated. Results: Ratio of EC and PVP was found to be the main influential factor for all the dependent variables studied. Drug loading dose was also found to influence the dependent variables but to a lesser extent. Physicochemical parameters of the prepared films were evaluated and found satisfactory. Activation energy for alfuzosin permeation has also been estimated and reported. Conclusion: The therapeutic system was found to be dermatologically non-irritant and hence, a therapeutically effective amount of alfuzosin hydrochloride can be delivered via a transdermal route.

Liquid crystalline systems for transdermal delivery of celecoxib: in vitro drug release and skin permeation studies.

Science.gov (United States)

Estracanholli, Eder André; Praça, Fabíola Silva Garcia; Cintra, Ana Beatriz; Pierre, Maria Bernadete Riemma; Lara, Marilisa Guimarães

2014-12-01

Liquid crystalline systems of monoolein/water could be a promising approach for the delivery of celecoxib (CXB) to the skin because these systems can sustain drug release, improve drug penetration into the skin layers and minimize side effects. This study evaluated the potential of these systems for the delivery of CXB into the skin based on in vitro drug release and skin permeation studies. The amount of CXB that permeated into and/or was retained in the skin was assayed using an HPLC method. Polarizing light microscopy studies showed that liquid crystalline systems of monoolein/water were formed in the presence of CXB, without any changes in the mesophases. The liquid crystalline systems decreased drug release when compared to control solution. Drug release was independent of the initial water content of the systems and CXB was released from cubic phase systems, irrespective of the initial water content. The systems released the CXB following zero-order release kinetics. In vitro drug permeation studies showed that cubic phase systems allowed drug permeation and retention in the skin layers. Cubic phase systems of monoolein/water may be promising vehicles for the delivery of CXB in/through the skin because it improved CXB skin permeation compared with the control solution.

Thermogravimetric analysis and fast pyrolysis of Milkweed.

Science.gov (United States)

Kim, Seung-Soo; Agblevor, Foster A

2014-10-01

Pyrolysis of Milkweed was carried out in a thermogravimetric analyzer and a bubbling fluidized bed reactor. Total liquid yield of Milkweed pyrolysis was between 40.74% and 44.19 wt% between 425 °C and 550 °C. The gas yield increased from 27.90 wt% to 33.33 wt% with increasing reaction temperature. The higher heating values (HHV) of the Milkweed bio-oil were relatively high (30.33-32.87 MJ/kg) and varied with reaction temperature, feeding rate and fluidization velocity. The selectivity for CO2 was highest within non-condensable gases, and the molar ratio of CO2/CO was about 3 at the different reaction conditions. The (13)C NMR analysis, of the bio-oil showed that the relative concentration carboxylic group and its derivatives was higher at 425 °C than 475 °C, which resulted in slightly higher oxygen content in bio-oil. The pH of aqueous phase obtained at 475 °C was 7.37 which is the highest reported for any lignocellulosic biomass pyrolysis oils. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of Hexane Vapour Permeation in Two Different Polymeric Membranes via an Innovative In-line FID Detection Method

Directory of Open Access Journals (Sweden)

Z. Petrusová

2017-07-01

Full Text Available This manuscript presents a novel method for the analysis of vapour permeation through polymeric membranes based on in-line analysis of the permeate with an FID detector. The hexane vapour permeation was studied for two commercially available membranes, namely low-density polyethylene (LDPE and thin-film-composite polyamide (PA membrane. The hexane permeation was studied at temperatures of 25–45 °C, hexane vapour activity in the range of 0.2–0.8 and trans-membrane pressures of 5–50 kPa. Two fundamentally different membranes were chosen to demonstrate the potential and sensitivity of the permeation apparatus. Upon increasing the temperature from 25 to 45 °C, the flux in LDPE was found to increase almost fourfold over the whole activity range. The nonlinear increase of the flux with activity indicates plasticization of the polymer by hexane. Contrarily, the flux in the PA membrane increases almost linearly with activity, with only a minor upward curvature. Since the PA is far away from any phase transition, it is less temperature-dependent than LDPE. The activation energy for permeation demonstrates that the temperature dependence in the LDPE membrane is dominated by changes in diffusion, whereas it is dominated by changes in solubility in the PA membrane.

Effects of Inorganic Fillers on the Thermal and Mechanical Properties of Poly(lactic acid).

Science.gov (United States)

Liu, Xingxun; Wang, Tongxin; Chow, Laurence C; Yang, Mingshu; Mitchell, James W

Addition of filler to polylactic acid (PLA) may affect its crystallization behavior and mechanical properties. The effects of talc and hydroxyapatite (HA) on the thermal and mechanical properties of two types of PLA (one amorphous and one semicrystalline) have been investigated. The composites were prepared by melt blending followed by injection molding. The molecular weight, morphology, mechanical properties, and thermal properties have been characterized by gel permeation chromatography (GPC), scanning electron microscope (SEM), instron tensile tester, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was found that the melting blending led to homogeneous distribution of the inorganic filler within the PLA matrix but decreased the molecular weight of PLA. Regarding the filler, addition of talc increased the crystallinity of PLA, but HA decreased the crystallinity of PLA. The tensile strength of the composites depended on the crystallinity of PLA and the interfacial properties between PLA and the filler, but both talc and HA filler increased the toughness of PLA.

Effects of Inorganic Fillers on the Thermal and Mechanical Properties of Poly(lactic acid

Directory of Open Access Journals (Sweden)

Xingxun Liu

2014-01-01

Full Text Available Addition of filler to polylactic acid (PLA may affect its crystallization behavior and mechanical properties. The effects of talc and hydroxyapatite (HA on the thermal and mechanical properties of two types of PLA (one amorphous and one semicrystalline have been investigated. The composites were prepared by melt blending followed by injection molding. The molecular weight, morphology, mechanical properties, and thermal properties have been characterized by gel permeation chromatography (GPC, scanning electron microscope (SEM, instron tensile tester, thermogravimetric analysis (TGA, differential scanning calorimetry (DSC, and dynamic mechanical analysis (DMA. It was found that the melting blending led to homogeneous distribution of the inorganic filler within the PLA matrix but decreased the molecular weight of PLA. Regarding the filler, addition of talc increased the crystallinity of PLA, but HA decreased the crystallinity of PLA. The tensile strength of the composites depended on the crystallinity of PLA and the interfacial properties between PLA and the filler, but both talc and HA filler increased the toughness of PLA.

Reduction of tritium permeation through Inconel 718 and Incoloy 800 HT by means of natural oxides

Energy Technology Data Exchange (ETDEWEB)

Aiello, A., E-mail: antonio.aiello@enea.it [ENEA C.R. Brasimone, I-40032 Camugnano (Italy); Utili, M.; Ciampichetti, A. [ENEA C.R. Brasimone, I-40032 Camugnano (Italy)

2011-10-01

Chronical releases of tritium from the helium primary coolant into the water secondary coolant is a fundamental safety issue in the design of a fusion reactor steam generator. It is well known that the steam/water circuit of a fusion reactor would be considered not relevant from a radiological point of view, while if a strong permeation of tritium will be present it will be released together with incondensable gases in the condenser. The permeation of hydrogen isotopes through candidate steam generator materials in different conditions was studied in the past. Further experiments demonstrated that nickel alloys of nuclear interest are always covered by a thin and adherent oxide layer able to reduce permeation of orders of magnitude. The major objective of this work is the evaluation of the permeated flux through nickel alloys, when exposed to pure hydrogen and to an oxidant gas stream, to verify the real permeability of these materials in conditions close to those foreseen in the helium side of the steam generator.

Tritium breeders and tritium permeation barrier coatings for fusion reactor

International Nuclear Information System (INIS)

Yamawaki, Michio; Kawamura, Hiroshi; Tsuchiya, Kunihiko

2004-01-01

A state of R and D of tritium breeders and tritium permeation barrier coatings for fusion reactor is explained. A list of candidate for tritium breeders consists of ceramics containing lithium, for examples, Li 2 O, Li 2 TiO 3 , Li 2 ZrO 3 , Li 4 SiO 4 and LiAlO 2 . The characteristics and form are described. The optimum particle size is from 1 to 10 μm. The production technologies of tritium breeders in the world are stated. Characteristics of ceramics with lithium as tritium breeders are compared. TiC, TiN/TiC, Al 2 O 3 and Cr 2 O 3 -SiO 2 -P 2 O 5 are tritium permeation barrier coating materials. These production methods and evaluation of characteristics are explained. (S.Y.)

Protection efficacy of gloves against components of the solvent in a sprayed isocyanate coating utilizing a reciprocating permeation panel.

Science.gov (United States)

Ceballos, Diana M; Reeb-Whitaker, Carolyn; Sasakura, Miyoko; Dills, Russell; Yost, Michael G

2015-04-01

Determine protection effectiveness of 5-mil natural rubber latex (0.13-mm), 5-mil nitrile rubber (0.13-mm), and 13-mil butyl rubber (0.33-mm) glove materials against solvents present in a commonly used automotive clear coat formulation using a novel permeation panel. The latex and nitrile gloves were the type commonly used by local autobody spray painters. Glove materials were tested by spraying an automotive clear coat onto an automated reciprocating permeation panel (permeation panel II). Temperature, relative humidity, and spray conditions were controlled to optimize clear coat loading homogeneity as evaluated by gravimetric analysis. Solvent permeation was measured using charcoal cloth analyzed by the National Institute for Occupational Safety and Health 1501 method. Natural rubber latex allowed 3-5 times the permeation of solvents relative to nitrile rubber for all 10 solvents evaluated: ethyl benzene, 2-heptanone, 1-methoxy-2-propyl acetate, o-xylene, m-xylene, p-xylene, n-butyl acetate, methyl isobutyl ketone, petroleum distillates, and toluene. There is a distinct behavior in solvent permeation before and after the coating dry time. Solvent permeation increased steadily before coating dry time and remained fairly constant after coating dry time. Butyl was not permeated by any of the solvents under the conditions tested. Commonly used 5-mil thick (0.13-mm) latex and nitrile gloves were ineffective barriers to solvents found in a commonly used clear coat formulation. Conversely, 13-mil (0.33-mm) butyl gloves were found to be protective against all solvents in the clear coat formulation. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Study of tritium permeation through Peach Bottom Steam Generator tubes

International Nuclear Information System (INIS)

Yang, L.; Baugh, W.A.; Baldwin, N.L.

1977-06-01

The report describes the equipment developed, samples tested, procedures used, and results obtained in the tritium permeation tests conducted on steam generator tubing samples which were removed from the Peach Bottom Unit No. 1 reactor

Analysis on tritium permeation in tritium storage bed with gas flowing calorimetry

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Hirofumi; Hayashi, Takumi; Suzuki, Takumi; Nishi, Masataka [Japan Atomic Energy Research Inst., Naka Fusion Research Establishment, Department of Fusion Engineering Research, Naka, Ibaraki (Japan); Yoshida, Hiroshi [Japan Atomic Energy Research Inst., Naka Fusion Research Establishment, ITER-Joint Centeral Team, Naka, Ibaraki (Japan)

2000-10-01

Tritium permeation amount in a tritium storage bed with gas flowing calorimetric was evaluated under a condition of new operation mode for International Thermonuclear Experimental Reactor (ITER). As a result, tritium permeation under the new operation mode was estimated to be about twice of that under the practical operation mode. This result show that it would be regardless in a view point of material control of tritium, however, it was suggested to be required additional tritium removal or evacuate system in a view points of safety control or performance of accountability or thermal insulating of the tritium storage bed. (author)

Nitride and carbide thin films as hydrogen permeation barrier on Manet steel

International Nuclear Information System (INIS)

Benamati, G.; Checchetto, R.; Bonelli, M.; Gratton, L.M.; Guzman, L.; Miotello, A.; Terlain, A.

1995-01-01

TiC / TiN bilayers, ∼ 1.2 μm thick, were deposited on Manet II steel by the ion beam assisted deposition technique to investigate the possible use of this ceramic coating as hydrogen barrier. Hydrogen permeation experiments in the temperature range 470-570 K showed indeed that this coating is a very efficient barrier to the hydrogen permeation being able to reduce the hydrogen flux up to two order of magnitude with respect to the uncoated steel. Preliminary compatibility tests between coated Manet II and Pb-17Li showed no attack of Pb-17Li to the steel. (orig.)

A description of an ultra high vacuum device for permeation measurements

International Nuclear Information System (INIS)

Gautsch, O.; Hodapp, G.

1984-01-01

The permeability of deuterium through austenitic stainless steel membranes is determined by means of an UHV-apparatus as a function of temperature, membrane thickness, and deuterium upstream driving pressure. The upstream side of the membrane is in contact with the liquid alloy of the eutectic Pb 83 Li 17 in order to represent the situation of a tritium breeding blanket of a fusion reactor. By means of the experimental results the amounts of tritium which permeate across the walls of the cooling tubes into the coolant will be determined. The purpose of this work is to describe the apparatus and the methods used for the determination of permeabilities. Also some preliminary results of permeation flux measurements are given

Transdermal delivery of carvedilol containing glycyrrhizin and chitosan as permeation enhancers: biochemical, biophysical, microscopic and pharmacodynamic evaluation.

Science.gov (United States)

Sapra, Bharti; Jain, Subheet; Tiwary, A K

2008-09-01

The present study was aimed at unveiling the influence of glycyrrhizin and chitosan on rat epidermis and to correlate these effects with percutaneous permeation characteristics of carvedilol. The permeation of carvedilol across excised rat epidermis was significantly higher (p vehicle as compared to propylene glycol:ethanol (7:3) mixture. Epidermis obtained after 12 hr treatment of viable rat skin with a glycyrrhizin-chitosan mixture showed significantly higher (p space, disordered lipid structure and corneocyte detachment as observed in SEM and TEM suggests great potential of glycyrrhizin for use as a percutaneous permeation enhancer.

Extração e pré-concentração de compostos orgânicos voláteis por permeação em membrana para análise cromatográfica Extraction and pre-concentration of volatile organic compounds by membrane permeation for chromatography analysis

Directory of Open Access Journals (Sweden)

Eduardo Carasek da Rocha

2000-02-01

Full Text Available This work discusses sample preparation processes for gas chromatography (GC based on the technique of extraction through membrane permeation (MPE. The MPE technique may be easily coupled to GC via a relatively simple device, which is a module that holds the membrane and is directly connected to the GC column. The possibility of operational errors due to sample handling is substantially reduced in an MPE-GC system because the sample preparation and the chemical analysis are accomplished as a one-step process. The MPE technique is of relatively wide application as it can be used for aqueous samples, solid samples and gaseous samples. Depending on the type of sample the extraction is performed with the membrane in direct contact with the sample or in contact with its headspace. The MPE-GC technique is very useful in trace analysis, due to the time-dependent enrichment of the analyte. A typical application of MPE-GC is the analysis of VOCs present in water that may be accomplished with detection limits at the low ppb (mugL-1 level.

Preparation, characterization and permeation studies of a nanovesicular system containing diclofenac for transdermal delivery.

Science.gov (United States)

Gaur, Praveen Kumar; Purohit, Suresh; Kumar, Yatendra; Mishra, Shikha; Bhandari, Anil

2014-02-01

Transdermal formulations contain permeation enhancer which causes skin damage. Ceramide 2 is natural lipid found in stratum corneum (SC). Drug-loaded nanovesicles of ceramide-2, cholesterol, palmitic acid, cholesteryl sulfate were formulated and analyzed for physical and biological properties. Diclofenac was used as a model drug. The vesicles were prepared using the film hydration method and characterized for physical parameters, in vitro drug release, accelerated stability studies and formulated into gel. Respective gels were compared with a commercial formulation (CEG) and plain carbopol gel (CG) containing drug for ex vivo, in vivo drug permeation and anti-inflammatory activity. The vesicles were stable with optimum physical parameters. DCG-1 showed 92.89% in vitro drug release. Ceramide vesicles showed drug release between 18 and 25 μg/cm(2) whereas CG and CEG released 0.33 and 1.35 μg/cm(2) drug, respectively. DCG-1 and CEG showed corresponding Cmax at 6 and 4 h, respectively. DCG-1 showed six times AUC than CEG. DCG-1 inhibited edema by 86.37% by 4th hour of application. The presence of ceramide 2 specifically promotes the drug permeation through SC and dermis and also contribute towards stability and non-irritancy. The composition of the nanovesicle played an important role in physical properties and drug permeation.

Buccal delivery of thiocolchicoside: in vitro and in vivo permeation studies.

Science.gov (United States)

Artusi, M; Santi, P; Colombo, P; Junginger, H E

2003-01-02

Thiocolchicoside, a muscle-relaxant agent, is administered by the oral, intra-muscular and topical route. After oral administration the extent of bioavailability compared with intra-muscular administration is low, due to a first pass effect. In this paper, the delivery of thiocolchicoside through oral mucosa is studied to improve the bioavailability. Thiocolchicoside in vitro permeation through porcine oral mucosa and in vivo buccal transport in humans were investigated. Two dosage forms, a bioadhesive disc and a fast dissolving disc for buccal and sublingual administration of thiocolchicoside, respectively, were designed. The in vitro permeation of thiocolchicoside through porcine buccal mucosa from these dosage forms was evaluated and compared with in vivo absorption. Results from in vitro studies demonstrated that thiocolchicoside is quite permeable across porcine buccal mucosa and that permeation enhancers, such as sodium taurocholate and sodium taurodeoxycholate, were not able to increase its flux. The in vivo thiocolchicoside absorption experiments, in which the drug loss from oral cavity was measured, indicated that both formulations could be useful for therapeutic application. The fast dissolving (sublingual) form resulted in a quick uptake of 0.5 mg of thiocolchicoside within 15 min whereas with the adhesive buccal form the same dose can be absorbed over an extended period of time.

Study and Thermogravimetric analysis of Poly N-4 Aminostyrol

International Nuclear Information System (INIS)

Meghezzi, A.; Lakhdar, Y.; Saidi, M.; Dadamoussa, B.

2006-01-01

The polyaminostyrol samples (PAS) and their copolymers with the styrol differing in position and quantity of amino-group, were obtained by polymerization of monomers on cyclogexan solution. The observed thermal effects were analyzed by the differential thermal analysis combined with a thermogravimetric analysis. It was found that the introduction of amino-groups into the polystyrols increased the temperature of total degradation of polymer from 150 till 260C. The increase in thermostability may be explained by the cohesion of macromolecules with the participation of amino-groups, which results in ammonium evolution, as well as in the decrease of valence area band of -NH2 grouping the region 3370-34440 cm. It was showed that the degree of cohesion formation and thermolysis rate depended on amino-group and their position into the cycle of benzene. (author)

A novel quantification method of pantaprazole sodium monohydrate in sesquihydrate by thermogravimetric analyzer.

Science.gov (United States)

Reddy, V Ranga; Rajmohan, M Anantha; Shilpa, R Laxmi; Raut, Dilip M; Naveenkumar, Kolla; Suryanarayana, M V; Mathad, Vijayavitthal T

2007-04-11

To demonstrate the applicability of thermogravimetric analyzer as a tool for the quantification of pantaprazole sodium monohydrate in sesquihydrate, studies have been conducted. Thermal analysis (DSC, TGA) crystallographic (PXRD) and spectroscopic techniques (FT-IR) were used for the characterization of the polymorphs. Thermogravimetric analysis (TGA) analysis was explored by high-resolution dynamic (Hi-Res-dynamic) and high-resolution modulated (Hi-Res-modulated) test procedures to quantify the hydrate polymorphic mixtures. The two polymorphic forms exhibited significant differences and good resolution in the second derivative thermogram generated by Hi-Res-modulated test procedure. Thus, the TGA with Hi-Res-modulated test procedure was considered for the quantification of monohydrate in sesquihydrate. The calibration plot was constructed from the known mixtures of two polymorphs by plotting the peak area of the second derivative thermogram against the weight percent of monohydrate. Using this novel approach, 1 wt% limit of detection (LOD) was achieved. The polymorphic purity results, obtained by TGA in Hi-Res-modulated test procedure were found to be in good agreement with the results predicted by FT-IR and was comparable with the actual values of the known polymorphic mixtures. The Hi-Res-modulated TGA technique is very simple and easy to perform the analysis.

Method for Determining the Activation Energy Distribution Function of Complex Reactions by Sieving and Thermogravimetric Measurements.

Science.gov (United States)

Bufalo, Gennaro; Ambrosone, Luigi

2016-01-14

A method for studying the kinetics of thermal degradation of complex compounds is suggested. Although the method is applicable to any matrix whose grain size can be measured, herein we focus our investigation on thermogravimetric analysis, under a nitrogen atmosphere, of ground soft wheat and ground maize. The thermogravimetric curves reveal that there are two well-distinct jumps of mass loss. They correspond to volatilization, which is in the temperature range 298-433 K, and decomposition regions go from 450 to 1073 K. Thermal degradation is schematized as a reaction in the solid state whose kinetics is analyzed separately in each of the two regions. By means of a sieving analysis different size fractions of the material are separated and studied. A quasi-Newton fitting algorithm is used to obtain the grain size distribution as best fit to experimental data. The individual fractions are thermogravimetrically analyzed for deriving the functional relationship between activation energy of the degradation reactions and the particle size. Such functional relationship turns out to be crucial to evaluate the moments of the activation energy distribution, which is unknown in terms of the distribution calculated by sieve analysis. From the knowledge of moments one can reconstruct the reaction conversion. The method is applied first to the volatilization region, then to the decomposition region. The comparison with the experimental data reveals that the method reproduces the experimental conversion with an accuracy of 5-10% in the volatilization region and of 3-5% in the decomposition region.

Interactions between oxygen permeation and homogeneous-phase fuel conversion on the sweep side of an ion transport membrane

KAUST Repository

Hong, Jongsup

2013-02-01

The interactions between oxygen permeation and homogeneous fuel oxidation reactions on the sweep side of an ion transport membrane (ITM) are examined using a comprehensive model, which couples the dependency of the oxygen permeation rate on the membrane surface conditions and detailed chemistry and transport in the vicinity of the membrane. We assume that the membrane surface is not catalytic to hydrocarbon or syngas oxidation. Results show that increasing the sweep gas inlet temperature and fuel concentration enhances oxygen permeation substantially. This is accomplished through promoting oxidation reactions (oxygen consumption) and the transport of the products and reaction heat towards the membrane, which lowers the oxygen concentration and increases the gas temperature near the membrane. Faster reactions at higher fuel concentration and higher inlet gas temperature support substantial fuel conversion and lead to a higher oxygen permeation flux without the contribution of surface catalytic activity. Beyond a certain maximum in the fuel concentration, extensive heat loss to the membrane (and feed side) reduces the oxidation kinetic rates and limits oxygen permeation as the reaction front reaches the membrane. The sweep gas flow rate and channel height have moderate impacts on oxygen permeation and fuel conversion due to the residence time requirements for the chemical reactions and the location of the reaction zone relative to the membrane surface. © 2012 Elsevier B.V.

Skin Delivery of EGCG and Silibinin: Potential of Peptide Dendrimers for Enhanced Skin Permeation and Deposition.

Science.gov (United States)

Shetty, Pallavi Krishna; Manikkath, Jyothsna; Tupally, Karnaker; Kokil, Ganesh; Hegde, Aswathi R; Raut, Sushil Y; Parekh, Harendra S; Mutalik, Srinivas

2017-08-01

The aim of the present study was to evaluate the ability of the peptide dendrimers to facilitate transdermal delivery of antioxidants, silibinin, and epigallocatechin-3-gallate (EGCG). Drug-peptide dendrimer complexes were prepared and evaluated for their ability to permeate across the skin. The data revealed the ready formation of complexes between drug and peptide dendrimer in a molar ratio of 1:1. In vitro permeation studies using excised rat skin and drug-peptide dendrimer complexes showed highest values for cumulative drug permeation at the end of 12 h (Q 12 ), with corresponding permeability coefficient (Kp) and enhancement ratio values also determined at this time point. With silibinin, 3.96-, 1.81-, and 1.06-fold increase in skin permeation was observed from silibinin-peptide dendrimer complex, simultaneous application of silibinin + peptide dendrimer, and pretreatment of skin with peptide dendrimer, respectively, in comparison with passive diffusion. With EGCG, 9.82-, 2.04-, and 1.72-fold increase in skin permeation was observed from EGCG-peptide dendrimer complex, simultaneous application of EGCG + peptide dendrimer, and pretreatment of skin with peptide dendrimer, respectively, in comparison with passive diffusion. The present study demonstrates the application of peptide dendrimers in effectively delivering antioxidants such as EGCG and silibinin into the skin, thus offering the potential to provide antioxidant effects when delivered via appropriately formulated topical preparations.

Nickel hydroxide electrode. 3: Thermogravimetric investigations of nickel (II) hydroxides

Science.gov (United States)

Dennstedt, W.; Loeser, W.

1982-01-01

Water contained in Ni hydroxide influences its electrochemical reactivity. The water content of alpha and beta Ni hydroxides is different with respect to the amount and bond strength. Thermogravimetric experiments show that the water of the beta Ni hydroxides exceeding the stoichiometric composition is completely removed at 160 deg. The water contained in the interlayers of the beta hydroxide, however, is removed only at higher temperatures, together with the water originating from the decomposition of the hydroxide. These differences are attributed to the formation of II bonds within the interlayers and between interlayers and adjacent main layers. An attempt is made to explain the relations between water content and the oxidizability of the Ni hydroxides.

Study on high-silicon boron-containing zeolite by thermogravimetric and IR-spectroscopy techniques

International Nuclear Information System (INIS)

Chukin, G.D.; Nefedov, B.K.; Surin, S.A.; Polinina, E.V.; Khusid, B.L.; Sidel'kovskaya, V.G.

1985-01-01

The structure identity of initial Na-forms of boron-containing and aluminosilicate high-silicon zeolites is established by thermogravimetric and IR-spectroscopy methods. The presence of boron in Na-forms of high-silicon zeolites is shown to lead to reduction of structure thermal stability. It is noted that thermal stability of the H-form of both high-silicon boron-containing and boron-free zeolites is practically equal and considerably higher than that of Na-forms

Protein permeation through polymer membranes for hybrid-type artificial pancreas

Energy Technology Data Exchange (ETDEWEB)

Burczak, K; Fujisato, Toshiya; Ikada, Yoshito [Kyoto Univ. (Japan); Hatada, Motoyoshi

1991-05-01

Hydrogel membranes were prepared by radiation crosslinking of poly (vinyl alcohol) (PVA) in aqueous solutions. Effects of PVA concentration, PVA molecular weight, and radiation dose on the permeation of insulin and immunoglobulin through the membranes were investigated. Glucose permeation was also studied. The crosslinking density affected the size of macromolecular mesh of hydrogel network as well as the water content of membrane responsible for the diffusion of the solutes. The diffusion coefficient linearly increased for all the solutes with the increasing water content in PVA hydrogels, indicating that diffusion occurs primarily through the water hydrating the polymer network. The increase in crosslinking density of hydrogels by changing PVA molecular weight brought about the decrease in mesh size of the hydrogels, which, in turn, had an influence on the diffusion of immunoglobulin, but not of insulin and glucose. (author).

Natural oils as skin permeation enhancers for transdermal delivery of olanzapine: in vitro and in vivo evaluation.

Science.gov (United States)

Aggarwal, Geeta; Dhawan, Sanju; HariKumar, S L

2012-03-01

The feasibility of development of transdermal delivery system of olanzapine utilizing natural oils as permeation enhancers was investigated. Penetration enhancing potential of corn (maize) oil, groundnut oil and jojoba oil on in vitro permeation of olanzapine across rat skin was studied. The magnitude of flux enhancement factor with corn oil, groundnut oil and jojoba oil was 7.06, 5.31 and 1.9 respectively at 5mg/ml concentration in solvent system. On the basis of in vitro permeation studies, eudragit based matrix type transdermal patches of olanzapine were fabricated using optimized concentrations of natural oils as permeation enhancers. All transdermal patches were found to be uniform with respect to physical characteristics. The interaction studies carried out by comparing the results of ultraviolet, HPLC and FTIR analyses for the pure drug, polymers and mixture of drug and polymers indicated no chemical interaction between the drug and excipients. Corn oil containing unsaturated fatty acids was found to be promising natural permeation enhancer for transdermal delivery of olanzapine with greatest cumulative amount of drug permeated (1010.68 μg/cm²/h) up to 24 h and caused no skin irritation. The fabricated transdermal patches were found to be stable. The pharmacokinetic characteristics of the final optimized matrix patch (T2) were determined after transdermal application to rabbits. The calculated relative bioavailability of TDDS was 113.6 % as compared to oral administration of olanzapine. The therapeutic effectiveness of optimized transdermal system was confirmed by tranquillizing activity in rotarod and grip mice model.

Permeation enhancing polymers in oral delivery of hydrophilic macromolecules: thiomer/GSH systems.

Science.gov (United States)

Bernkop-Schnürch, A; Kast, C E; Guggi, D

2003-12-05

Thiolated polymers (= thiomers) in combination with reduced glutathione (GSH) were shown to improve the uptake of hydrophilic macromolecules from the GI tract. The mechanism responsible for this permeation enhancing effect seems to be based on the thiol groups of the polymer. These groups inhibit protein tyrosine phosphatase, being involved in the closing process of tight junctions, via a GSH-mediated mechanism. The strong permeation enhancing effect of various thiomer/GSH systems such as poly(acrylic acid)-cysteine/GSH or chitosan-4-thio-butylamidine (chitosan-TBA)/GSH could be shown via permeation studies on freshly excised intestinal mucosa in Ussing-type chambers. Furthermore, the efficacy of the system was also shown in vivo. By utilizing poly(acrylic acid)-cysteine/GSH as carrier matrix, an absolute oral bioavailability for low molecular weight heparin of 19.9 +/- 9.3% and a pharmacological efficacy--calculated on the basis of the areas under the reduction in serum glucose levels of the oral formulation versus subcutaneous (s.c.) injection-for orally given insulin of 7% could be achieved. The incorporation of salmon calcitonin in chitosan-TBA/GSH led on the other hand to a pharmacological efficacy based on the areas under the reduction in plasma calcium levels of the oral thiomer formulation versus intravenous (i.v.) injection of 1.3%. Because of this high efficacy (i), the possibility to combine thiomer/GSH systems with additional low molecular weight permeation enhancers acting in other ways (ii) and minimal toxicological risks as these polymers are not absorbed from the GI tract (iii), thiolated polymers represent a promising novel tool for the oral administration of hydrophilic macromolecules.

Characterization and utilization of the permeate and retentate obtained after “dead-end” ultrafiltration

Directory of Open Access Journals (Sweden)

Vasić Vesna M.

2013-01-01

Full Text Available In the recent years, with the increase in bioethanol production, the increasing amounts of distillery wastewater are generated. Such wastewater (stillage is one of the most polluted waste product of the food and beverage industries. The present study evaluates the treatment of distillery wastewater by ultrafiltration (UF, in order to reduce its pollution and evaluate the composition of the permeate and retentate. Polyethersulfone ultrafiltration membrane with molecular weight cut-off (MWCO 30000 Da, was used for the experiments. The UF was carried out in dead-end mode. The results of the analyses of the permeate and retentate obtained after ultrafiltration were considered as well as different ways for their further utilization. The pollutant level in the permeate was decreased significantly in comparison to the raw stillage, and suspended solids were completely removed from the stillage. [Projekat Ministarstva nauke Republike Srbije, br. TR 31002

Preparation and Skin Permeation Study of N, N- Diethyl- meta-Toluamide Semi Solid Formulations

Directory of Open Access Journals (Sweden)

Solmaz Ghaffari

2013-06-01

Full Text Available N,N-Diethyl meta Toluamide (DEET is an insect repellent agent that contrary to its benefits, if is used in formulations with high skin permeation, will produce side effects of different severity. This study attempted to achieve a semi-solid DEET containing formulation with good appearance, sufficient spreadity, suitable viscosity for tube and jar filling, compatible pH with skin, reasonable stability, longer release time, and the less skin permeation. To obtain such a formulation, three types of DEET containing semi solids including gels (hydrophile, creams (emulsion and ointments (lipophile, and their characteristics were compared with each other and with Off! Brand. Results showed that one of the prepared creams with the proper viscosity, stability, appearance and spreadity, had the least drug release in six hours and less skin permeation of DEET as compared with Off!. Hence the preparation was introduced as the optimal formulation.

Surface oxygen vacancy and oxygen permeation flux limits of perovskite ion transport membranes

KAUST Repository

Hunt, Anton

2015-09-01

© 2015 Elsevier B.V. The mechanisms and quantitative models for how oxygen is separated from air using ion transport membranes (ITMs) are not well understood, largely due to the experimental complexity for determining surface exchange reactions at extreme temperatures (>800°C). This is especially true when fuels are present at the permeate surface. For both inert and reactive (fuels) operations, solid-state oxygen surface vacancies (δ) are ultimately responsible for driving the oxygen flux, JO2. In the inert case, the value of δ at either surface is a function of the local PO2 and temperature, whilst the magnitude of δ dictates both the JO2 and the inherent stability of the material. In this study values of δ are presented based on experimental measurements under inert (CO2) sweep: using a permeation flux model and local PO2 measurements, collected by means of a local gas-sampling probe in our large-scale reactor, we can determine δ directly. The ITM assessed was La0.9Ca0.1FeO3-δ (LCF); the relative resistances to JO2 were quantified using the pre-defined permeation flux model and local PO2 values. Across a temperature range from 825°C to 1056°C, δ was found to vary from 0.007 to 0.029 (<1%), safely within material stability limits, whilst the permeate surface exchange resistance dominates. An inert JO2 limit was identified owing to a maximum sweep surface δ, δmaxinert. The physical presence of δmaxinert is attributed to a rate limiting step shift from desorption to associative electron transfer steps on the sweep surface as PO2 is reduced. Permeate surface exchange limitations under non-reactive conditions suggest that reactive (fuel) operation is necessary to accelerate surface chemistry for future work, to reduce flux resistance and push δpast δmaxinert in a stable manner.

Influence of adsorbed hydrogen molecules on the hydrogen permeation and recycling

International Nuclear Information System (INIS)

Banno, T.

1987-01-01

Hydrogen permeation through a thin iron membrane has been measured using a molecular hydrogen gas and/or a weakly ionized rf-discharge as particle sources. Transient and steady state values of the permeation flux φ p were obtained in the regime where the surface penetration of H and the recombinative release of H 2 are rate-determining. φ p is then proportional to the flux density ψ of the particles which impinge on the membrane upstream. The proportionality factors depend on the nature (atomic or molecular) of the incident particles, on temperature (in particular for a molecular driving gas) and on the ratio of the surface recombinative release rate constants (2σk r ) u and (2σk r ) d up- and downstream, respectively. (orig.)

Characterization of Thin Film Polymers Through Dynamic Mechanical Analysis and Permeation

Science.gov (United States)

Herring, Helen

2003-01-01

Thin polymer films are being considered, as candidate materials to augment the permeation resistance of cryogenic hydrogen fuel tanks such as would be required for future reusable launch vehicles. To evaluate performance of candidate films after environmental exposure, an experimental study was performed to measure the thermal/mechanical and permeation performance of six, commercial-grade materials. Dynamic storage modulus, as measured by Dynamic Mechanical Analysis, was found over a range of temperatures. Permeability, as measured by helium gas diffusion, was found at room temperature. Test data was correlated with respect to film type and pre-test exposure to moisture, elevated temperature, and cryogenic temperature. Results indicated that the six films were comparable in performance and their resistance to environmental degradation.

Silicon Carbide as a tritium permeation barrier in tungsten plasma-facing components

Science.gov (United States)

Wright, G. M.; Durrett, M. G.; Hoover, K. W.; Kesler, L. A.; Whyte, D. G.

2015-03-01

The control of tritium inventory is of great importance in future fusion reactors, not only from a safety standpoint but also to maximize a reactor's efficiency. Due to the high mobility of hydrogenic species in tungsten (W) one concern is the loss of tritium from the system via permeation through the tungsten plasma-facing components (PFC). This can lead to loss of tritium through the cooling channels of the wall thereby mandating tritium monitoring and recovery methods for the cooling system of the first wall. The permeated tritium is then out of the fuel cycle and cannot contribute to energy production until it is recovered and recycled into the system.

Nitride and carbide thin films as hydrogen permeation barrier on MANET steel

International Nuclear Information System (INIS)

Benamati, G.

1994-01-01

TiC/TiN bilayers, - 1.2 μm thick, were deposited on Manet II steel by the ion beam assisted deposition technique to investigate the possible use of this ceramic coating as hydrogen barrier. Hydrogen permeation experiments in the temperature range 470-570 K showed indeed that this coating is a very efficient barrier to the hydrogen permeation being able to reduce the hydrogen flux up to two order of magnitude with respect to the uncoated steel. Preliminary compatibility tests between coated Manet II and Pb-17Li showed no attack of Pb-17Li to the steel. (author) 8 refs.; 2 figs.; 1 tab

Incorporation of whey permeate, a dairy effluent, in ethanol fermentation to provide a zero waste solution for the dairy industry.

Science.gov (United States)

Parashar, Archana; Jin, Yiqiong; Mason, Beth; Chae, Michael; Bressler, David C

2016-03-01

This study proposes a novel alternative for utilization of whey permeate, a by-product stream from the dairy industry, in wheat fermentation for ethanol production using Saccharomyces cerevisiae. Whey permeates were hydrolyzed using enzymes to release fermentable sugars. Hydrolyzed whey permeates were integrated into wheat fermentation as a co-substrate or to partially replace process water. Cold starch hydrolysis-based simultaneous saccharification and fermentation was done as per the current industrial protocol for commercial wheat-to-ethanol production. Ethanol production was not affected; ethanol yield efficiency did not change when up to 10% of process water was replaced. Lactic acid bacteria in whey permeate did not negatively affect the co-fermentation or reduce ethanol yield. Whey permeate could be effectively stored for up to 4 wk at 4 °C with little change in lactose and lactic acid content. Considering the global abundance and nutrient value of whey permeate, the proposed strategy could improve economics of the dairy and biofuel sectors, and reduce environmental pollution. Furthermore, our research may be applied to fermentation strategies designed to produce value-added products other than ethanol. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Development of a low tritium partial pressure permeation system for mass transport measurement in lead lithium eutectic

International Nuclear Information System (INIS)

Pawelko, R.; Shimada, M.; Katayama, K.; Fukada, S.; Terai, T.

2014-01-01

A new experimental system designed to investigate tritium mass transfer properties in materials important to fusion technology is operational at the Safety and Tritium Applied Research (STAR) facility located at the Idaho National Laboratory (INL). The tritium permeation measurement system was developed as part of the Japan/US TITAN collaboration to investigate tritium mass transfer properties in liquid lead lithium eutectic (LLE) alloy. The system is similar to a hydrogen/deuterium permeation measurement system developed at Kyushu University and also incorporates lessons learned from previous tritium permeation experiments conducted at the STAR facility. This paper describes the experimental system that is configured specifically to measure tritium mass transfer properties at low tritium partial pressures. We present preliminary tritium permeation results for α-Fe and α-Fe/LLE samples at 600degC and at tritium partial pressures between 1.0E-3 and 2.4 Pain helium. The preliminary results are compared with literature data. (author)

Effect of Enhancers on in vitro and in vivo Skin Permeation and Deposition of S-Methyl-L-Methionine.

Science.gov (United States)

Kim, Ki Taek; Kim, Ji Su; Kim, Min-Hwan; Park, Ju-Hwan; Lee, Jae-Young; Lee, WooIn; Min, Kyung Kuk; Song, Min Gyu; Choi, Choon-Young; Kim, Won-Serk; Oh, Hee Kyung; Kim, Dae-Duk

2017-07-01

S-methyl- L -methionine (SMM), also known as vitamin U, is commercially available as skin care cosmetic products for its wound healing and photoprotective effects. However, the low skin permeation expected of SMM due to its hydrophilic nature with a log P value of -3.3, has not been thoroughly addressed. The purpose of this study thus was to evaluate the effect of skin permeation enhancers on the skin permeation/deposition of SMM. Among the enhancers tested for the in vitro skin permeation and deposition of SMM, oleic acid showed the most significant enhancing effect. Moreover, the combination of oleic acid and ethanol further enhanced in vitro permeation and deposition of SMM through hairless mouse skin. Furthermore, the combination of oleic acid and ethanol significantly increased the in vivo deposition of SMM in the epidermis/dermis for 12 hr, which was high enough to exert a therapeutic effect. Therefore, based on the in vitro and in vivo studies, the combination of oleic acid and ethanol was shown to be effective in improving the topical skin delivery of SMM, which may be applied in the cosmetic production process for SMM.

A study of hydrogen permeation in aluminum alloy treated by various oxidation processes

International Nuclear Information System (INIS)

Song Wenhai; Long Bin

1997-01-01

A set of oxide coatings was formed on the surface of an Al alloy (wt%: Fe, 0.24; Si, 1.16; Cu, 0.05-0.2; Zn, 0.1; Al, residual) by means of various oxidation processes. The hydrogen permeability through the aluminum alloy and its coating materials was determined by a vapor phase permeation technique at temperatures ranging from 400 to 500 C using high-purity H 2 (99.9999%) gas with an upstream hydrogen pressure of 10 4 -10 5 Pa. The experimental results show that the hydrogen permeability through aluminum oxide coating is 100-2000 times lower than that through the aluminum alloy substrate. This means that the aluminum oxide is a significant hydrogen permeation barrier. A high hydrogen permeation resistance was observed in an oxide layer prefilmed in 200 C water, while an anodized aluminum oxide film had a less obstructive effect, possibly caused by the porous structure of the anodic oxide. The hydrogen permeability through films of aluminum oxide was not a simple function of the aluminum-oxide phase configuration. (orig.)

Organic fluid permeation through fluoropolymer membranes

Science.gov (United States)

Nemser, Stuart M.; Kosaraju, Praveen; Bowser, John

2015-07-14

Separation of the components of liquid mixtures is achieved by contacting a liquid mixture with a nonporous membrane having a fluoropolymer selectively permeable layer and imposing a pressure gradient across the membrane from feed side to permeate side. Unusually high transmembrane flux is obtained when the membrane is subjected to one or more process conditions prior to separation. These include (a) leaving some residual amount of membrane casting solvent in the membrane, and (b) contacting the membrane with a component of the mixture to be separated for a duration effective to saturate the membrane with the component.

Phase Change Permeation Technology For Environmental Control Life Support Systems

Science.gov (United States)

Wheeler, Raymond M.

2014-01-01

Use of a phase change permeation membrane (Dutyion [Trademark]) to passively and selectively mobilize water in microgravity to enable improved water recovery from urine/brine for Environment Control and Life Support Systems (ECLSS) and water delivery to plans for potential use in microgravity.

Diclofenac Salts, VIII. Effect of the Counterions on the Permeation through Porcine Membrane from Aqueous Saturated Solutions

Science.gov (United States)

Fini, Adamo; Bassini, Glenda; Monastero, Annamaria; Cavallari, Cristina

2012-01-01

The following bases: monoethylamine (EtA), diethylamine (DEtA), triethylamine (TEtA), monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), pyrrolidine (Py), piperidine (Pp), morpholine (M), piperazine (Pz) and their N-2-hydroxyethyl (HE) analogs were employed to prepare 14 diclofenac salts. The salts were re-crystallized from water in order to obtain forms that are stable in the presence of water. Vertical Franz-type cells with a diffusional surface area of 9.62 cm2 were used to study the permeation of these diclofenac salts from their saturated solutions through an internal pig ear membrane. The receptor compartments of the cells contained 100 mL of phosphate buffer (pH 7.4); a saturated solution (5 mL) of each salt was placed in the donor compartment, thermostated at 37 °C. Aliquots were withdrawn at predetermined time intervals over 8 h and then immediately analyzed by HPLC. Fluxes were determined by plotting the permeated amount, normalized for the membrane surface area versus time. Permeation coefficients were obtained dividing the flux values J by the concentration of the releasing phase—that is, water solubility of each salt. Experimental results show that fluxes could be measured when diclofenac salts with aliphatic amines are released from a saturated aqueous solution. Different chemical species (acid, anion, ion pairs) contribute to permeation of the anti-inflammatory agent even though ion-pairs could be hypothesized to operate to a greater extent. Permeation coefficients were found higher when the counterion contains a ring; while hydroxy groups alone do not appear to play an important role, the ring could sustain permeation, disrupting the organized domains of the membrane. PMID:24300300

Kinetic Model of LiFePO4 Formation Using Non-Isothermal Thermogravimetric Analysis

Directory of Open Access Journals (Sweden)

Abdul Halim

2014-03-01

Full Text Available The formation reaction of LiFePO4 from decomposition of precursors LiOH, FeSO4.7H2O and (NH42HPO4 with mol ratio of Li:Fe:P=1:1:1 was investigated. The experiment was carried out by thermogravimetric differential thermal analysis (TG-DTA method using nitrogen as atmosfer at a constant heating rate to obtain kinetic constant parameters. Several heating rates were selected, there are 5, 7, 10, 15, 17.5, 22.5 and 25 °C/min. Activation energy, pre-exponential factor and reaction order were taken using Kissinger method and obtained respectively 56.086 kJ/mol, 6.95×108 min-1, and 1.058. Based on fitting result between reaction model and experiment were obtained that reaction obeyed the three dimension diffusion model. © 2014 BCREC UNDIP. All rights reservedReceived: 19th September 2013; Revised: 9th December 2013; Accepted: 23rd January 2014 [How to Cite: Halim, A., Widiyastuti, W., Setyawan, H., Winardi, S. (2014. Kinetic of LiFePO4 For-mation Using Non-isothermal Thermogravimetric Analysis. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (1: 60-65. (doi:10.9767/bcrec.9.1.5508.60-65][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.1.5508.60-65] 

Skin penetration and tissue permeation after topical administration of diclofenac.

Science.gov (United States)

Hagen, Martina; Baker, Mark

2017-09-01

Topical delivery of drugs is an alternative to oral administration, often with similar efficacy but potentially a more favorable tolerability profile. However, topical formulations need to be able to penetrate the skin and permeate to the target areas in quantities sufficient to exert a therapeutic effect. Many factors can affect this process, including the physicochemical properties of the drug, the formulation used, and the site and mode of application. It is believed that measurement of drug concentrations at the sites of action may be an indicator of their likely efficacy. This review addresses these issues, with reference to topically administered diclofenac in osteoarthritis. Articles relevant to this review were identified after a systematic search of Medline and Embase, using the key words "diclofenac", "topical administration" and "osteoarthritis" in the search strategy. The sparse data available indicate that topical diclofenac can penetrate and permeate to deeper tissues, with a lower plasma to tissue ratio than oral diclofenac. The tissue diclofenac levels after topical delivery are sustained over time (at least several hours). However, there is not enough data to establish how diclofenac levels in the joint compare with IC 50 levels (50% of the maximum inhibition of prostaglandin synthesis) established following oral administration. After topical application, diclofenac can penetrate the skin and permeate to deeper tissues, where it reaches a concentration that appears to be sufficient to exert a therapeutic effect. More robust methods are required for in vivo characterization to better estimate the clinical efficacy of topically applied drugs.

Development of a hydrogen permeation sensor for future tritium applications

Energy Technology Data Exchange (ETDEWEB)

Llivina, L.; Colominas, S.; Abellà, J., E-mail: sergi.colominas@iqs.es

2014-10-15

Highlights: • Designing and testing of a hydrogen permeation sensor. • Palladium and α-iron have been used as a hydrogen permeation materials in the sensor. • The experiments performed using both membranes showed that the operation of the sensors in the equilibrium mode required at least several hours to reach the hydrogen equilibrium pressure. - Abstract: Tritium monitoring in lithium–lead eutectic is of great importance for the performance of liquid blankets in fusion reactors. In addition, tritium measurements will be required in order to proof tritium self-sufficiency in liquid metal breeding systems. On-line hydrogen (isotopes) sensors must be design and tested in order to accomplish these goals. In this work, an experimental set up was designed in order to test the permeation hydrogen sensors at 500 °C. This experimental set-up allowed working with controlled environments (different hydrogen partial pressures) and the temperature was measured using a thermocouple connected to a temperature controller that regulated an electrical heater. In a first set of experiments, a hydrogen sensor was constructed using an α-iron capsule as an active hydrogen area. The sensor was mounted and tested in the experimental set up. In a second set of experiments the α-iron capsule was replaced by a welded thin palladium disk in order to minimize the death volume. The experiments performed using both membranes (α-iron and palladium) showed that the operation of the sensors in the equilibrium mode required at least several hours to reach the hydrogen equilibrium pressure.

Determination of effective moisture diffusivity and drying kinetics for poplar sawdust by thermogravimetric analysis under isothermal condition.

Science.gov (United States)

Chen, Dengyu; Zheng, Yan; Zhu, Xifeng

2012-03-01

The current study presents a thermogravimetric method to determine the effective moisture diffusivity and drying kinetics of biomass. Drying experiments on poplar sawdust were performed at four temperatures (60, 70, 80, and 90°C) by a thermogravimetric analyzer (TGA). The major assumption in experimentally determining effective diffusivity by Fick's diffusion equation is that drying is mass transfer limited and temperature remains isothermal during drying. The results indicated that TGA could well achieve these determining conditions. The drying process of sawdust mostly took place in the falling rate period. Midilli-Kucuk model showed the best fit for all experimental data. The effective diffusivity values changed from 9.38 × 10(-10)m(2)/s to 1.38 × 10(-9)m(2)/s within the given temperature range, and the activation energy was calculated to be 12.3 kJ/mol. Copyright © 2011 Elsevier Ltd. All rights reserved.

Hydrogen permeation properties of Pd-coated V89.8Cr 10Y0.2 alloy membrane using WGS reaction gases

KAUST Repository

Jeon, Sungil

2013-05-01

The influence of co-existing gases on the hydrogen permeation was studied through a Pd-coated V89.8Cr10Y0.2 alloy membrane. Preliminary hydrogen permeation experiments have been confirmed that hydrogen flux was 6.26 ml/min/cm2 for a Pd-coated V 89.8Cr10Y0.2 alloy membrane (thick: 0.5 mm) using pure hydrogen as feed gas. Also, the hydrogen permeation flux decreased with decrease of hydrogen partial pressure at constant pressure when H 2/CO2 and H2/CO2/H2S mixture applied as feed gas respectively and permeation fluxes were satisfied with Sievert\\'s law in different feed conditions. It was found from XRD and SEM results after permeation test that the Pd-coated V89.8Cr 10Y0.2 alloy membrane had good stability and durability for various mixture feeding conditions. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Hydrogen permeation properties of Pd-coated V89.8Cr 10Y0.2 alloy membrane using WGS reaction gases

KAUST Repository

Jeon, Sungil; Park, Junghoon

2013-01-01

The influence of co-existing gases on the hydrogen permeation was studied through a Pd-coated V89.8Cr10Y0.2 alloy membrane. Preliminary hydrogen permeation experiments have been confirmed that hydrogen flux was 6.26 ml/min/cm2 for a Pd-coated V 89.8Cr10Y0.2 alloy membrane (thick: 0.5 mm) using pure hydrogen as feed gas. Also, the hydrogen permeation flux decreased with decrease of hydrogen partial pressure at constant pressure when H 2/CO2 and H2/CO2/H2S mixture applied as feed gas respectively and permeation fluxes were satisfied with Sievert's law in different feed conditions. It was found from XRD and SEM results after permeation test that the Pd-coated V89.8Cr 10Y0.2 alloy membrane had good stability and durability for various mixture feeding conditions. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Investigating the sonophoresis effect on the permeation of diclofenac sodium using 3D skin equivalent.

Science.gov (United States)

Aldwaikat, Mai; Alarjah, Mohammed

2015-01-01

Ultrasound temporally increases skin permeability by altering stratum corneum SC function (sonophoresis). The objective of this study was to evaluate the effect of variable ultrasound conditions on the permeation of diclofenac sodium DS with range of physicochemical properties through EpiDerm™. Permeation studies were carried out in vitro using Franz diffusion cell. HPLC method was used for the determination of the concentration of diclofenac sodium in receiving compartment. Parameters like ultrasound frequency, application time, amplitude, and mode of sonication and distance of ultrasound horn from skin were investigated, and the conditions where the maximum enhancement rate obtained were determined. Application of ultrasound enhanced permeation of diclofenac sodium across EpiDerm™ by fivefolds. The most effective enhancing parameters were power sonication of 20kHz frequency, 20% amplitude at continuous mode for 5min. Copyright © 2014. Published by Elsevier B.V.

Stability of tritium permeation prevention barrier with TiC and TiN + TiC coating

International Nuclear Information System (INIS)

Shan Changqi; Chen Qingwang; Dai Shaoxia; Jiang Weisheng

1999-01-01

The stability of tritium permeation prevention barrier of 316L stainless steel with coating TiC and TiN + TiC under the conditions of very large thermal gradient, thermal cycling and plasma irradiation is researched. The research includes two aspects: one is the study on the stability resisting H + plasma irradiation; another is on the ability of two coating materials when they are used in long term under the condition of very large thermal gradient and cycling. The results show that TiC and TiN + TiC composite coating materials, after chemical heat treatment and forming tritium permeation prevention barrier, can resist H + ion irradiation, and also can resist very large thermal gradient and thermal cycling. The long time experiments show that tritium permeation prevention barrier of those coating materials is stable when they are used in long term

Peculiarities of hydrogen permeation through Zr–1%Nb alloy and evaluation of terminal solid solubility

Energy Technology Data Exchange (ETDEWEB)

Denisov, E.A.; Kompaniets, M.V.; Kompaniets, T.N., E-mail: tkompaniets@spbu.ru; Bobkova, I.S.

2016-04-15

Hydrogen permeation through Zr–1%Nb alloy was studied at the temperature below the temperature of α-β transition. Analysis of the transient permeation curves from a closed volume in a surface limited regime allowed to determine total and mobile hydrogen concentrations. At the mobile hydrogen concentration of 4.3 at% a part of the absorbed hydrogen is cut out of permeation process. Increase of the mobile hydrogen concentration in α-phase of Zr–1%Nb alloy is ceasing at the concentration of (5.5 ± 0.3) at%, which is the maximum possible concentration of the mobile hydrogen in α-phase of the studied alloy. From this moment on all absorbed hydrogen is spent on hydride formation. The obtained results are compared with those obtained by means of traditional techniques for terminal solid solubility determination.

Investigation of aluminised steel as a barrier to tritium using accelerator-based and hydrogen permeation techniques

Energy Technology Data Exchange (ETDEWEB)

Sokhi, R S; Forcey, K S; Ross, D K; Earwaker, L G [Birmingham Univ. (UK). School of Physics and Space Research

1989-04-01

Aluminised steel has been proposed as a barrier to tritium permeation in fusion reactors. The properties of these materials as tritium barriers have been studied using accelerator-based techniques and hydrogen permeation methods. The aluminide layers has been characterised by Rutherford backscattering spectroscopy (RBS) and nuclear reaction analysis (NRA) techniques using the 3 MV Dynamitron accelerator based at the School of Physics and Space Research Radiation Centre. The effectiveness of the aluminide layer as a tritium barrier has been measured directly by a conventional permeation apparatus over a range of temperatures. The effect of high temperatures on the structure of the aluminide layer has been examined. Any correlation between the composition of the layer and its effectiveness as a tritium barrier is also discussed. (orig.).

Deuterium permeation of amorphous alumina coating on 316L prepared by MOCVD

Science.gov (United States)

Li, Shuai; He, Di; Liu, Xiaopeng; Wang, Shumao; Jiang, Lijun

2012-01-01

The deuterium permeation behavior of the alumina coating on 316L stainless steel prepared by metal organic chemical vapor deposition (MOCVD) was investigated. The alumina coating was also characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). It was found that the as-prepared coating consisted of amorphous alumina. This alumina coating had a dense, crack-free and homogeneous morphology. Although the alumina coating was amorphous, effective suppression of deuterium permeation was demonstrated. The deuterium permeability of the alumina coating was 51-60 times less than that of the 316L stainless steel and 153-335 times less than that of the referred low activation martensitic steels at 860-960 K.

Thermogravimetric study of superconducting YBa2Cu3O9-x in hydrogen

International Nuclear Information System (INIS)

Swaminathan, K.; Janaki, J.; Rao, G.V.N.; Sreedharan, O.M.; Radhakrishnan, T.S.

1988-01-01

The thermogravimetric curve of YBa 2 Cu 3 O 9-x in hydrogen exhibits five steps, the first two corresponding to the reduction of copper oxide to copper by about 683 K (as identified by XRD on quenched samples) followed by three more steps predominantly due to hydration-dehydration behaviour of BaO. The need for blank corrections and the choice of 1223 K as the temperature for the determination of oxygen stoichiometry are discussed. 6 refs.; 2 figs.; 1 table

Thermogravimetric analysis of silicon carbide-silicon nitride fibers at ambient to 1000 C in air

Science.gov (United States)

Daniels, J. G.; Ledbetter, F. E., III; Clemons, J. M.; Penn, B. G.

1984-01-01

Thermogravimetric analysis of silicon carbide-silicon nitride fibers was carried out at ambient to 1000 C in air. The weight loss over this temperature range was negligible. In addition, the oxidative stability at high temperature for a short period of time was determined. Fibers heated at 1000 C in air for fifteen minutes showed negligible weight loss (i.e., less than 1 percent).

Oxygen- and hydrogen-permeation measurements on-mixed conducting SrFeCo{sub 0.5}O{sub y} ceramic membrane material

Energy Technology Data Exchange (ETDEWEB)

Serra, E.; Casagrande, E.; La Barbera, A. [ENEA UTS MAT, CR Casaccia, 00060 S.M. di Galeria, Roma (Italy); Alvisi, M. [ENEA UTS MAT, CR Brindisi, 72100 Brindisi (Italy); Bezzi, G.; Mingazzini, C. [ENEA UTS MAT, CR Faenza, 48018 Faenza (Italy)

2008-02-15

The SrFeCo{sub 0.5}O{sub y} system combines high electronic/ionic conductivity with appreciable oxygen permeability at elevated temperatures. This system has potential use in high-temperature electrochemical applications such as solid oxide fuel cells, batteries, sensors, and oxygen separation membranes. Dense ceramic membranes of SrFeCo{sub 0.5}O{sub y} are prepared by pressing a ceramic powder prepared by using a sol-gel combustion technique. Oxygen and hydrogen permeation at high temperature on this material are studied. Measurements are conducted using a time-dependent permeation method at the temperature in the range of 1073-1273 K with oxygen- and hydrogen-driving pressures in the range (3 x 10{sup 2})-(1 x 10{sup 5}) Pa (300-1000 mbar). The maximum oxygen-permeated flux at 1273 K is 6.5 x 10{sup -3} mol m{sup -2} s{sup -1}. The activation energies for the O{sub 2}-permeation fluxes and diffusivities are 240 and 194 kJ/mol, respectively. Due to the high fragility, the high temperature for the measurements and the high oxygen permeation through such material, a special membrane holder, and compression sealing system have been designed and realized for the permeation apparatus. (author)

Gas Permeation Processes in Biogas Upgrading: A Short Review

Czech Academy of Sciences Publication Activity Database

Kárászová, Magda; Sedláková, Zuzana; Izák, Pavel

2015-01-01

Roč. 69, č. 10 (2015), s. 1277-1283 ISSN 0366-6352 R&D Projects: GA MŠk(CZ) LD14094; GA MŠk LH14006; GA ČR GA14-12695S Institutional support: RVO:67985858 Keywords : biogas upgrading * memranes * gas permeation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.326, year: 2015

Analysis of skin permeation-enhancing mechanism of iontophoresis using hydrodynamic pore theory.

Science.gov (United States)

Manabe, E; Numajiri, S; Sugibayashi, K; Morimoto, Y

2000-05-15

The effects of constant DC iontophoresis (0-1.5 mA/0.966 cm(2)) on the permeation of three hydrophilic compounds, antipyrine (ANP, M.W. 188.23), sucrose (SR, M.W. 342.30) and 1-kestose (KT, M.W. 506.73), through excised hairless rat skin were evaluated using hydrodynamic pore theory. The electro-osmotic flow caused by iontophoresis was measured using deuterium oxide (D(2)O). The penetration-enhancing mechanism of iontophoresis was found to increase solvent flow through electro-osmosis and pore enlargement and/or new pore production in the skin barrier, together with enhancement of electrochemical potential difference across the skin. These effects were closely related to the strength of the current applied. The electro-osmotic flow of D(2)O (J(D(2)O)) greatly enhanced the skin permeation clearance of all hydrophilic penetrants (CL(drug)). Pore production was classified into reversible and irreversible processes, which resulted from lower (0-0.5 mA/0.966 cm(2)) and higher (0.5-1. 5 mA/0.966 cm(2)) currents, respectively. Thus, the enhancing effects of iontophoresis on skin permeation of nonionic hydrophilic compounds can be explained by increase in pore size and higher solvent flow.

Effect of emulsification on the skin permeation and UV protection of catechin.

Science.gov (United States)

Yoshino, Sachie; Mitoma, Tomoaki; Tsuruta, Keiko; Todo, Hiroaki; Sugibayashi, Kenji

2014-06-01

An anti-aging effect may be obtained by skin application of tea catechins (Camellia sinensis) since they have high ultraviolet (UV)-protection activity. In this study, the skin permeation of catechin (C), epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECg) and epigallocatechin gallate (EGCg) was determined and compared, and the effect of emulsification on the skin permeation of C was measured. The UV-protective effect of C was also determined. The in vitro skin permeability of each catechin derivative was determined using side-by-side diffusion of cells. The UV-protective effect of C was determined by applying different concentrations of C to the solution or emulsion on a three-dimensional cultured human skin model or normal human epidermal keratinocytes with UV-irradiation. ECg and EGCg with gallate groups showed lower skin permeability than C, EC and EGC without gallate groups, suggesting that the skin permeability of catechin derivatives may be dependent on the existence of a gallate group. Interestingly, the skin permeation of C was increased by an o/w emulsification. In addition, the C emulsion showed a significantly higher UV-protective effect by C than that with its aqueous solution. These results suggest that the o/w emulsion of catechin derivatives is probably useful as a cosmetic formulation with anti-aging efficacy.

Evaluation of a dynamic dissolution/permeation model

DEFF Research Database (Denmark)

Sironi, Daniel; Christensen, Mette; Rosenberg, Jörg

2017-01-01

-steady state). To this end, a model case was construed: compacts of pure crystalline hydrocortisone methanolate (HC·MeOH) of slow release rates were prepared, and their dissolution and permeation determined simultaneously in a side-by-side setup, separated by a biomimetic barrier (Permeapad...... dissolution rate and flux influenced each other. Interestingly, for all the dynamic scenarios, the incremental flux values obtained correlated nicely with the corresponding actual donor concentrations. Furthermore, donor depletion was tested using a HC solution. The dynamic interplay between decrease in donor...

Measurement of blood-brain barrier permeation in rats during exposure to 2450-MHz microwaves

International Nuclear Information System (INIS)

Ward, T.R.; Elder, J.A.; Long, M.D.; Svendsgaard, D.

1982-01-01

Adult rats anesthesized with pentobarbital and injected intravenously with a mixture of [ 14 C] sucrose and [ 3 H] inulin were exposed for 30 min to an environment at an ambient temperature of 22, 30, or 40 degrees C, or were exposed at 22 degrees C to 2450-MHz CW microwave radiation at power densities of 0, 10, 20, or 30 mW/cm2. Following exposure, the brain was perfused and sectioned into eight regions, and the radioactivity in each region was counted. The data were analyzed by two methods. First, the data for each of the eight regions and for each of the two radioactive tracers were analyzed by regression analysis for a total of 16 analyses and Bonferroni's Inequality was applied to prevent false positive results from numerous analyses. By this conservative test, no statistically significant increase in permeation was found for either tracer in any brain region of rats exposed to microwaves. Second, a profile analysis was used for a general change in tracer uptake across all brain regions. Using this statistical method, a significant increase in permeation was found for sucrose but not for inulin. A correction factor was then derived from the warm-air experiments to correct for the increase in permeation of the brain associated with change in body temperature. This correction factor was applied to the data for the irradiated animals. After correcting the data for thermal effects of the microwave radiation, no significant increase in permeation was found

Gastrointestinal behavior of nano- and microsized fenofibrate: In vivo evaluation in man and in vitro simulation by assessment of the permeation potential.

Science.gov (United States)

Hens, Bart; Brouwers, Joachim; Corsetti, Maura; Augustijns, Patrick

2015-09-18

The purpose of this study was (i) to evaluate the gastrointestinal behavior of micro- and nanosized fenofibrate in humans and (ii) to develop a simple yet qualitatively predictive in vitro setup that simulates the observed absorption-determining factors. Commercially available micro- and nanoparticles of fenofibrate (Lipanthyl® and Lipanthylnano®, respectively) were administered orally to five healthy volunteers in fasting and postprandial conditions. Intraluminal and systemic drug concentrations were determined as reference data for the development of a predictive in vitro setup. To capture the observed solubility/permeability interplay, in vitro dissolution testing was performed in the presence of a permeation bag with sink conditions. In fasting conditions, intake of nanosized fenofibrate generated increased duodenal concentrations compared to microsized fenofibrate, which was reflected in an improved systemic exposure. In postprandial conditions, duodenal concentrations were greatly enhanced for both formulations, however without an accompanying increase in systemic exposure. It appeared that micellar encapsulation of the highly lipohilic fenofibrate limited its potential to permeate from fed state intestinal fluids. To capture these in vivo observations in an in vitro setup, classic dissolution testing was combined with permeation assessment into a permeation bag with sink conditions. In case of fasting conditions, the dissolution/permeation approach allowed for an improved discriminative power between micro- and nanosized fenofibrate by better simulating the dynamic interplay of dissolution and absorption. In case of postprandial conditions, the observed solubility-permeability interplay could be simulated using the dissolution/permeation approach in combination with biorelevant media (FeSSGFFortimel and FeSSIF-V2) to mimic micellar entrapment and reduced permeation potential of fenofibrate. For the first time, reduced permeation of a lipophilic drug

Needs and gaps in the development of aluminum-based corrosion and T-permeation barriers for DEMO blankets

Energy Technology Data Exchange (ETDEWEB)

Wulf, Sven-Erik, E-mail: sven-erik.wulf@kit.edu; Krauss, Wolfgang; Konys, Jürgen

2015-10-15

Highlights: • New processes for barriers based on electroplating introduced in the last years. • New processes ECA and ECX able to overcome former fabrication problems. • Scales by ECA showed long-term compatibility in flowing Pb–Li (>12,000 h). • Further fusion relevant characterization and optimization of scales is required. • Qualification of T-permeation properties is urgently needed. - Abstract: Low-activation-ferritic–martensitic (RAFM) steels are candidates for structural materials in different blanket designs foreseen for DEMO and partly for TBM's tested in ITER. In all designs the liquid breeder Pb–15.7Li is in direct contact with the structural material, and thus two major topics – corrosion and T-permeation – influence the reliable, safe and economical application of such combination of breeder and structural material. As bare RAFM steels exhibit high corrosion rates of up to 400 μm/h in flowing Pb–15.7Li, Al-based coatings made by different coating processes were developed during the last 15 years and showed promising results in protecting RAFM steels from corrosion and T-permeation reduction. Especially barriers made by HDA, and electroplating (ECA, ECX), proved their ability to protect Eurofer against corrosion in flowing Pb–15.7Li. However, available T-permeation data for coated RAFM steels are rare and partly ambiguous for these coatings. This paper summarizes the state-of-the-art of aluminum-based barrier development and points out gaps and needs in future scale characterization and T-permeation barrier development. Additionally, necessary qualification steps on the path toward a reliable fabrication route are presented that is required to produce aluminum-based corrosion and T-permeation barriers on RAFM steels for blanket applications in future fusion reactors like DEMO.

Characteristics of curcumin using cyclic voltammetry, UV–vis, fluorescence and thermogravimetric analysis

International Nuclear Information System (INIS)

Masek, Anna; Chrzescijanska, Ewa; Zaborski, Marian

2013-01-01

Highlights: • Electrooxidation of curcumin was investigated with cyclic voltammetry. • The curcumin is irreversibly oxidized at the platinum electrode in anhydrous media. • Absorbance, fluorescence and thermogravimetric analysis of curcumin was studied. • The HOMO and Mapped Electron Densities were calculated using HyperChem. • Oxidation mechanism for curcumin proposed. -- Abstract: Curcumin, the yellow, primary bioactive component of turmeric, has recently received attention from chemists due its wide range of potential biological applications as an antioxidant, anti-inflammatory, and anti-carcinogenic agent. The electrochemical behaviour of curcumin at a platinum electrode has been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The oxidation of curcumin is an irreversible process that proceeds in two steps in 0.1 M (C 4 H 9 ) 4 NClO 4 in acetonitrile. The process of oxidation and its kinetics have been investigated. The rate constant, electron transfer coefficient and diffusion coefficients for the electrochemical oxidation of curcumin were determined. A mechanism for the oxidation of curcumin is proposed. The data obtained are consistent with the current literature and suggest that voltammetric studies on mechanically transferred solids may be a convenient method for elucidating the electrochemical oxidation mechanisms of compounds in anhydrous media. Theoretical calculations regarding the optimization of curcumin, electronic properties like highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were calculated using with HyperChem software by AM1 semi-empirical method. The properties of curcumin in a homogeneous environment were investigated using spectroscopic techniques and thermogravimetric analysis

The influence of pH on the in vitro permeation of rhodium through human skin.

Science.gov (United States)

Jansen Van Rensburg, Sané; Franken, Anja; Du Plessis, Jeanetta; Du Plessis, Johannes Lodewykus

2017-06-01

Workers in precious metals refineries are at risk of exposure to salt compounds of the platinum group metals through inhalation, as well as through the skin. Rhodium salt permeation through the skin has previously been proven using rhodium trichloride (RhCl 3 ) dissolved in synthetic sweat at a pH of 6.5. However, the skin surface pH of refinery workers may be lower than 6.5. The aim of this study was to investigate the influence of pH 6.5 and 4.5 on the in vitro permeation of rhodium through intact Caucasian skin using Franz diffusion cells. A concentration of 0.3 mg mL -1 rhodium was used and analyses were performed using inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry. Results indicated a cumulative increase in permeation over 24 h. Rhodium permeation after 12 h was significantly greater at pH 4.5 (1.56 ± 0.24 ng cm -2 ) than at 6.5 (0.85 ± 0.13 ng cm -2 ; p = 0.02). At both pH levels, there was a highly significant difference ( p rhodium remaining in the skin (1428.68 ± 224.67 ng cm -2 at pH 4.5 and 1029.90 ± 115.96 ng cm -2 at pH 6.5) and the mass that diffused through (0.88 ± 0.17 ng cm -2 at pH 4.5 and 0.62 ± 0.10 ng cm -2 at pH 6.5). From these findings, it is evident that an acidic working environment or low skin surface pH may enhance permeation of rhodium salts, contributing to sensitization and adverse health effects.

Thermogravimetric analysis of fuel film evaporation

Institute of Scientific and Technical Information of China (English)

HU Zongjie; LI Liguang; YU Shui

2006-01-01

Thermogravimetric analysis (TGA) was compared with the petrochemical distillation measurement method to better understand the characteristics of fuel film evaporation at different wall tem- peratures. The film evaporation characteristics of 90# gasoline, 93# gasoline and 0# diesel with different initial thicknesses were investigated at different environmental fluxes and heating rates. The influences of heating rate, film thickness and environmental flux on fuel film evaporation for these fuels were found. The results showed that the environmental conditions in TGA were similar to those for fuel films in the internal combustion engines, so data from TGA were suitable for the analysis of fuel film evaporation. TGA could simulate the key influencing factors for fuel film evaporation and could investigate the basic quantificational effect of heating rate and film thickness. To get a rapid and sufficient fuel film evaporation, sufficiently high wall temperature is necessary. Evaporation time decreases at a high heating rate and thin film thickness, and intense gas flow is important to promoting fuel film evaporation. Data from TGA at a heating rate of 100℃/min are fit to analyze the diesel film evaporation during cold-start and warming-up. Due to the tense molecular interactions, the evaporation sequence could not be strictly divided according to the boiling points of each component for multicomponent dissolved mixture during the quick evaporation process, and the heavier components could vaporize before reaching their boiling points. The 0# diesel film would fully evaporate when the wall temperature is beyond 250℃.

Performance Tests of a Permeation Sensor for Test Blanket Modules Using Liquid Metal

International Nuclear Information System (INIS)

Choi, B. G.; Lee, D. W.; Lee, E. H.; Yoon, J. S.; Kim, S. K.; Shin, K. I.; Jin, H. G.

2013-01-01

The tritium extraction from a breeder is one of the key technologies and its methods have been investigated. For developing the tritium extraction methods and evaluating the amount of tritium in the system, a reliable and correct sensor is required to measure the hydrogen concentration in liquid metal breeder. There are several researches for developing the sensors in the ITER participants and especially, EU has developed the permeation sensors trying to selecting materials with low Serviette's constant (solubility) and high hydrogen diffusivity coefficient. However, EU's response time is still too long time about tens of minutes to measure the tritium concentration in the online system. We have been performing the preliminary tests with designed and fabricated sensors to solve the late response of sensor. However, we could not continue the tests because of the membrane's oxidation (pure Fe) and the difficulty of welding nonferrous metals. In present study, a permeation sensor made of vacuum flanges with a porous plate inside is proposed not only to eliminate the difficulty of the fabrication but to optimize the performance of sensor. The permeation sensor to measure the hydrogen isotopes in liquid metal breeder has been proposed and evaluated to overcome the limitation of a long response time for various shapes and materials. We found that the previous sensors have limitation; the oxidation problems (pure Fe) and the difficulty in welding (nonferrous metals). Therefore we proposed a permeation sensor with the vacuum flanges filled with porous disks to eliminate the problems. By using the CF flanges, the problem caused by welding is removed. But the permeable response time of sensors took a long time to reach the pressure equivalent

Effect of feed flow pattern on the distribution of permeate fluxes in desalination by direct contact membrane distillation

KAUST Repository

Soukane, Sofiane

2017-05-31

The current study aims to highlight the effect of flow pattern on the variations of permeate fluxes over the membrane surface during desalination in a direct contact membrane distillation (DCMD) flat module. To do so, a three dimensional (3D) Computational Fluid Dynamics (CFD) model with embedded pore scale calculations is implemented to predict flow, heat and mass transfer in the DCMD module. Model validation is carried out in terms of average permeate fluxes with experimental data of seawater desalination using two commercially available PTFE membranes. Average permeate fluxes agree within 6% and less with experimental values without fitting parameters. Simulation results show that the distribution of permeate fluxes and seawater salinity over the membrane surface are strongly dependent on momentum and heat transport and that temperature and concentration polarization follow closely the flow distribution. The analysis reveals a drastic effect of recirculation loops and dead zones on module performance and recommendations to improve MD flat module design are drawn consequently.

Measuring deuterium permeation through tungsten near room temperature under plasma loading using a getter layer and ion-beam based detection

Directory of Open Access Journals (Sweden)

Stefan Kapser

2017-08-01

Full Text Available A method to measure deuterium permeation through tungsten near room temperature under plasma loading is presented. The permeating deuterium is accumulated in a getter layer of zirconium, titanium or erbium, respectively, on the unexposed side of the sample. Subsequently, the amount of deuterium in the getter is measured ex-situ using nuclear reaction analysis. A cover layer system on the getter prevents direct loading of the getter with deuterium from the gas phase during plasma loading. In addition, it enables the distinction of deuterium in the getter and at the cover surface. The method appears promising to add additional permeation measurement capabilities to deuterium retention experiments, also in other plasma devices, without the need for a complex in-situ permeation measurement setup.

Interactions of coal gangue and pine sawdust during combustion of their blends studied using differential thermogravimetric analysis.

Science.gov (United States)

Zhang, Yuanyuan; Zhang, Zhezi; Zhu, Mingming; Cheng, Fangqin; Zhang, Dongke

2016-08-01

The interactions between coal gangue and pine sawdust during the combustion process were studied using thermogravimetric analysis. The effect of the blending ratio, oxygen concentration and heating rate on the weight loss (TG) and differential thermogravimetric (TGA) profiles was examined. The TG and DTG curves of the blends were not additives of those of the individual materials, suggesting that interactions between coal gangue and pine sawdust had occurred during the combustion, especially in the temperature range of 400-600°C. Kinetic analysis confirmed that the combustion of coal gangue, pine sawdust and their blends was chemical reaction controlled. Further analysis revealed that the interactions between coal gangue and pine sawdust were primarily due to thermal effects rather than structural changes, with the thermal inertia of coal gangue dominating over the behaviour of the blends. The interactions decreased with decreasing the coal gangue ratio in the blend, oxygen concentration and heating rate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hydrogen isotope permeation in elastomeric materials

International Nuclear Information System (INIS)

Steinmeyer, R.H.; Braun, J.D.

1976-01-01

The permeabilities of elastomeric and polymeric materials to hydrogen isotopes were measured at room temperature. The technique for measuring permeation rates is based on the following constant-volume method: a fixed pressure of gas is applied to one side of the specimen to be studied and the permeability constant is determined from the observed rate of pressure increase in an initially evacuated volume on the other side of the specimen. Permeability constants for hydrogen, deuterium, and tritium were measured for Mylar, Teflon, Kapton, Saran, Buna-N, and latex rubber. Results were compared with literature values for hydrogen and deuterium where available and showed excellent agreement

Hydrogen diffusion, dissolution and permeation of nonmetallic solids

International Nuclear Information System (INIS)

Elleman, T.S.; Rao, D.; Verghese, K.; Zumwalt, L.

1979-01-01

A review of hydrogen diffusion, dissolution and permeation in metal oxides, carbides, nitrides, halides and hydrides is presented. Results are organized by compound and an effort has been made to resolve differences between measured results where wide disparities exist. The document has been prepared to provide needed data for the development of fusion reactor blankets but the results should be generally useful in technologies that involve interactions between hydrogen and non-metals

In vitro skin permeation and decontamination of the organophosphorus pesticide paraoxon under various physical conditions--evidence for a wash-in effect.

Science.gov (United States)

Misik, Jan; Pavlikova, Ruzena; Josse, Denis; Cabal, Jiri; Kuca, Kamil

2012-09-01

Misuse of various chemicals, such as chemical warfare agents, industrial chemicals or pesticides during warfare or terrorists attacks requires adequate protection. Thus, development and evaluation of novel decontamination dispositives and techniques are needed. In this study, in vitro permeation and decontamination of a potentially hazardous compound paraoxon, an active metabolite of organophosphorus pesticide parathion, was investigated. Skin permeation and decontamination experiments were carried out in modified Franz diffusion cells. Pig skin was used as a human skin model. Commercially produced detergent-based washing solutions FloraFree(™) and ArgosTM were used as decontamination means. The experiments were done under "warm", "cold", "dry" and "wet" skin conditions in order to determine an effect of various physical conditions on skin permeation of paraoxon and on a subsequent decontamination process. There was no significant difference in skin permeation of paraoxon under warm, cold and dry conditions, whereas wet conditions provided significantly higher permeation rates. In the selected conditions, decontamination treatments performed 1 h after a skin exposure did not decrease the agent volume that permeated through the skin. An exception were wet skin conditions with non-significant decontamination efficacy 18 and 28% for the FloraFree(™) and Argos(™) treatment, respectively. In contrast, the skin permeation of paraoxon under warm, cold and dry conditions increased up to 60-290% following decontamination compared to non-decontaminated controls. This has previously been described as a skin wash-in effect.

Biomass Thermogravimetric Analysis: Uncertainty Determination Methodology and Sampling Maps Generation

Science.gov (United States)

Pazó, Jose A.; Granada, Enrique; Saavedra, Ángeles; Eguía, Pablo; Collazo, Joaquín

2010-01-01

The objective of this study was to develop a methodology for the determination of the maximum sampling error and confidence intervals of thermal properties obtained from thermogravimetric analysis (TG), including moisture, volatile matter, fixed carbon and ash content. The sampling procedure of the TG analysis was of particular interest and was conducted with care. The results of the present study were compared to those of a prompt analysis, and a correlation between the mean values and maximum sampling errors of the methods were not observed. In general, low and acceptable levels of uncertainty and error were obtained, demonstrating that the properties evaluated by TG analysis were representative of the overall fuel composition. The accurate determination of the thermal properties of biomass with precise confidence intervals is of particular interest in energetic biomass applications. PMID:20717532

Hydrogen Adsorption in Zeolite Studied with Sievert and Thermogravimetric Methods

International Nuclear Information System (INIS)

Lesnicenoks, P; Sivars, A; Grinberga, L; Kleperis, J

2012-01-01

Natural clinoptilolite (mixture from clinoptilolite, quartz and muscovite) is activated with palladium and tested for hydrogen adsorption capability at temperatures RT - 200°C. Thermogravimetric and volumetric methods showed that zeolite activated with palladium (1.25%wt) shows markedly high hydrogen adsorption capacity - up to 3 wt%. Lower amount of adsorbed hydrogen (∼1.5 wt%) was found for raw zeolite and activated with higher amount of palladium sample. Hypothesis is proposed that the heating of zeolite in argon atmosphere forms and activates the pore structure in zeolite material, where hydrogen encapsulation (trapping) is believed to occur when cooling down to room temperature. An effect of catalyst (Pd) on hydrogen sorption capability is explained by spillover phenomena were less-porous fractions of natural clinoptilolite sample (quartz and muscovite) are involved.

Mineralogical and chemical-physical effects of hydrocarbon permeation in composite liners and cut-off walls. Final report; Mineralogische und chemisch-physikalische Auswirkungen der Permeation von Kohlenwasserstoffen in Kombinationsdichtungen und -dichtwaenden. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Kalbe, U; Berger, W; Mueller, W; Brune, M; Eckardt, J; Tatzky-Gerth, R; Ache, W; Goebbels, J [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany); Breu, J; Kerzdoerfer, H [Regensburg Univ. (Germany). Inst. fuer Anorganische Chemie

2000-05-31

Composite liner systems (HDPE geomembrane and compacted mineral liner) are used in Germany in landfills and for the lining of contaminated sites according to the technical regulations. It is expected that these lining systems provide a highly efficient and reliable technical barrier for the long-term groundwater protection. To support these expectations and assess the performance of the liner system even under extreme conditions, various composite liner systems were exposed to a mixture of 9 liquid hydrocarbons and their permeation behaviour was studied in permeation cells over 12 years. The cells were now dismantled and changes in the liner materials were carefully measured and controlled. The following issues were pursued in the research project: - effect of long-term hydrocarbon permeation and immersion on the properties of the geomembrane, - determination of the vertical distribution of organic contaminants in the mineral liner, - changes in the mineralogical, micromorphological and soil mechanical properties of the mineral liner brought about by the contaminant mixture, - investigation of the influence of microbial activity on the mineral layer, - modelling of the pollutant transport in the composite liner system. Neither geomembrane nor most of the tested mineral liners exhibited significant changes. Hydrocarbon permeation was proved to have been substantially suppressed by the composite liner. (orig.) [German] Zur Sicherung von Deponien und Altlasten mit dem Ziel eines langfristig wirksamen Grundwasserschutzes werden seit Mitte der 80er Jahre Kombinationsdichtungen (Verbund aus Kunststoffdichtungsbahn und mineralischer Dichtschichten) eingesetzt. Um deren Langzeitbestaendigkeit auch unter extremen Bedingungen bewerten zu koennen, wurden Permeationsmesszellen, welche die Verhaeltnisse in der Deponie nachstellen und ueber einen Zeitraum von 12 Jahren mit einem Mehrkomponentengemisch konzentrierter organischer Verbindungen beaufschlagt worden waren, zerlegt und

Ionic Selectivity and Permeation Properties of Human PIEZO1 Channels.

Directory of Open Access Journals (Sweden)

Radhakrishnan Gnanasambandam

Full Text Available Members of the eukaryotic PIEZO family (the human orthologs are noted hPIEZO1 and hPIEZO2 form cation-selective mechanically-gated channels. We characterized the selectivity of human PIEZO1 (hPIEZO1 for alkali ions: K+, Na+, Cs+ and Li+; organic cations: TMA and TEA, and divalents: Ba2+, Ca2+, Mg2+ and Mn2+. All monovalent ions permeated the channel. At a membrane potential of -100 mV, Cs+, Na+ and K+ had chord conductances in the range of 35-55 pS with the exception of Li+, which had a significantly lower conductance of ~ 23 pS. The divalents decreased the single-channel permeability of K+, presumably because the divalents permeated slowly and occupied the open channel for a significant fraction of the time. In cell-attached mode, 90 mM extracellular divalents had a conductance for inward currents carried by the divalents of: 25 pS for Ba2+ and 15 pS for Ca2+ at -80 mV and 10 pS for Mg2+ at -50 mV. The organic cations, TMA and TEA, permeated slowly and attenuated K+ currents much like the divalents. As expected, the channel K+ conductance increased with K+ concentration saturating at ~ 45 pS and the KD of K+ for the channel was 32 mM. Pure divalent ion currents were of lower amplitude than those with alkali ions and the channel opening rate was lower in the presence of divalents than in the presence of monovalents. Exposing cells to the actin disrupting reagent cytochalasin D increased the frequency of openings in cell-attached patches probably by reducing mechanoprotection.

Effect of alcohol on skin permeation and metabolism of an ester-type prodrug in Yucatan micropig skin.

Science.gov (United States)

Fujii, Makiko; Ohara, Rieko; Matsumi, Azusa; Ohura, Kayoko; Koizumi, Naoya; Imai, Teruko; Watanabe, Yoshiteru

2017-11-15

We studied the effect that three alcohols, ethanol (EA), propanol (PA), and isopropanol (IPA), have on the skin permeation of p-hydroxy benzoic acid methyl ester (HBM), a model ester-type prodrug. HBM was applied to Yucatan micropig skin in a saturated phosphate buffered solution with or without 10% alcohol, and HBM and related materials in receptor fluid and skin were determined with HPLC. In the absence of alcohol, p-hydroxy benzoic acid (HBA), a metabolite of HBM, permeated the skin the most. The three alcohols enhanced the penetration of HBM at almost the same extent. The addition of 10% EA or PA to the HBM solution led to trans-esterification into the ethyl ester or propyl ester of HBA, and these esters permeated skin as well as HBA and HBM did. In contrast, the addition of 10% IPA promoted very little trans-esterification. Both hydrolysis and trans-esterification in the skin S9 fraction were inhibited by BNPP, an inhibitor of carboxylesterase (CES). Western blot and native PAGE showed the abundant expression of CES in micropig skin. Both hydrolysis and trans-esterification was simultaneously catalyzed by CES during skin permeation. Our data indicate that the alcohol used in dermal drug preparations should be selected not only for its ability to enhance the solubility and permeation of the drug, but also for the effect on metabolism of the drug in the skin. Copyright © 2017 Elsevier B.V. All rights reserved.

Design of a permeator against vacuum for tritium extraction from eutectic lithium-lead in a DCLL DEMO

Energy Technology Data Exchange (ETDEWEB)

Garcinuño, Belit, E-mail: belit.garcinuno@ciemat.es [CIEMAT-LNF (Laboratorio Nacional de Fusión), Madrid (Spain); Rapisarda, David [CIEMAT-LNF (Laboratorio Nacional de Fusión), Madrid (Spain); Fernández, Iván [Fundación & Departamento de Ingeniería Energética, UNED, Madrid (Spain); CIEMAT-LNF (Laboratorio Nacional de Fusión), Madrid (Spain); Moreno, Carlos; Palermo, Iole; Ibarra, Ángel [CIEMAT-LNF (Laboratorio Nacional de Fusión), Madrid (Spain)

2017-04-15

Highlights: • A conceptual design of a Permeator Against Vacuum is presented. • The efficiency is dependent on geometry and Tritium transport. • The use of different membrane materials is discussed. • A squared PAV with alternated PbLi flowing and vacuum flat ducts is designed. • 80% efficiency of Tritium extraction is accomplished under DCLL-BB requirements. - Abstract: One of the most important issues in future fusion power plants is the extraction of tritium generated in the breeders in order to achieve self-sufficiency. When the breeder is a liquid metal one of the most promising techniques is the Permeation Against Vacuum, whose principle is based on tritium diffusion through a permeable membrane in contact with the liquid metal carrier and its further extraction by a vacuum pump. A conceptual design of permeator has been developed, taking into account the features of a DEMO reactor with a Dual Coolant Lithium Lead (DCLL) breeder blanket. The study is based on the analysis of different membranes and geometries aiming at the overall efficiency (extraction capability) of the device, as well as its compatibility with the breeder material. The permeator is based on a rectangular section multi-channel distribution where the liquid metal channels and vacuum channels are alternated in order to maximize the contact area and therefore to promote tritium transport from the bulk to the walls. The resulting permeator design has an excellent estimated extraction efficiency, of 80%, in a relatively compact device.

Thermogravimetric kinetics of corn stalk pretreated by oleaginous fungi Cunninghamella echinulata.

Science.gov (United States)

Wu, Jianguo; Gao, Shi; Wan, Jilin; Zeng, Yelin; Ma, Fuying; Zhang, Xiaoyu

2011-04-01

The thermogravimetric and composition of corn stalk pretreated by oleaginous fungi Cunninghamella echinulata had been studied in this paper. Results indicated that pretreatment by oleaginous fungi C. echinulata could decrease the activation energy and make the pyrolysis more efficient and energy-saving. By bio-pretreatment, the contents of elements agreed with the weight loss, sugar content, and oil contents, especially the sulfur content was greatly decreased, greatly eliminating the inventory of gas contamination such as the emission of SOx and making the pyrolysis more environmentally friendly. Therefore, corn stalk with sugar pretreated by oleaginous fungi C. echinulata should be a good pyrolysis material to obtain high quality bio-oil. Copyright © 2011 Elsevier Ltd. All rights reserved.

Thermogravimetric and x-ray diffraction analyses of Luna-24 regolith samples

International Nuclear Information System (INIS)

Deshpande, V.V.; Dharwadkar, S.R.; Jakkal, V.S.

1979-01-01

Two samples of Luna-24 were analysed by X-ray diffraction and thermogravimetric (TG) techniques. The sample 24123.12 shows a weight loss of nearly 0.85 percent between 23O-440deg C and followed by 1.16 percent weight gain from 500 to 800deg C. The sample 23190.13 showed only a weight gain of about 1.5 percent from 5O0deg C to 900deg C. X-ray diffraction analyses show the presence of olivine, plagioclase, pigeonite, enstatite, and native iron in both the virgin samples. The heated samples, however, show that only the native iron got oxidized to iron oxide. The other constituents remain unaltered. (auth.)

Toward enhanced hydrogen generation from water using oxygen permeating LCF membranes

KAUST Repository

Wu, Xiao-Yu; Chang, Le; Uddi, Mruthunjaya; Kirchen, Patrick; Ghoniem, Ahmed F.

2015-01-01

and flow rates on the feed and sweep sides on the water thermolysis rate and oxygen flux. A single step reaction mechanism is proposed for surface reactions, and three-resistance permeation models are derived. Results show that water thermolysis

Importance of the Direct Contact of Amorphous Solid Particles with the Surface of Monolayers for the Transepithelial Permeation of Curcumin.

Science.gov (United States)

Kimura, Shunsuke; Kasatani, Sachiha; Tanaka, Megumi; Araki, Kaeko; Enomura, Masakazu; Moriyama, Kei; Inoue, Daisuke; Furubayashi, Tomoyuki; Tanaka, Akiko; Kusamori, Kosuke; Katsumi, Hidemasa; Sakane, Toshiyasu; Yamamoto, Akira

2016-02-01

The amorphization has been generally known to improve the absorption and permeation of poorly water-soluble drugs through the enhancement of the solubility. The present study focused on the direct contact of amorphous solid particles with the surface of the membrane using curcumin as a model for water-insoluble drugs. Amorphous nanoparticles of curcumin (ANC) were prepared with antisolvent crystallization method using a microreactor. The solubility of curcumin from ANC was two orders of magnitude higher than that of crystalline curcumin (CC). However, the permeation of curcumin from the saturated solution of ANC was negligible. The transepithelial permeation of curcumin from ANC suspension was significantly increased as compared to CC suspension, while the permeation was unlikely correlated with the solubility, and the increase in the permeation was dependent on the total concentration of curcumin in ANC suspension. The absorptive transport of curcumin (from apical to basal, A to B) from ANC suspension was much higher than the secretory transport (from basal to apical, B to A). In vitro transport of curcumin through air-interface monolayers is large from ANC but negligible from CC particles. These findings suggest that the direct contact of ANC with the absorptive membrane can play an important role in the transport of curcumin from ANC suspension. The results of the study suggest that amorphous particles may be directly involved in the transepithlial permeation of curcumin.

Study of the cathodic depolarization theory with hydrogen permeation and the bacteria Desulfovibrio desulfuricans

International Nuclear Information System (INIS)

Romero, M. F. de; Duque, Z.; Rinco, O. T. de; Perez, O.; Araujo, I.

2003-01-01

A Desulfovibrio desulfuricans ssp. desulfuricans (SRB) was used to study the permeation of hydrogen, using a Devanatan and Stachurski cell and a palladium sheet. The aim was to evaluate cathodic depolarization as a Sulfate-Reducing Bacteria action mechanisms in Microbiologically Induced Corrosion. The permeation tests were run with and without cathodic polarization, using a sterile deaerated culture medium inoculated with 10% SRB concentrated at 10''8 cell/ml. the results indicate bacterial growth in the order of 10''9-10''10 cel/ml after 18 h both in the polarized and non-polarized, tests, indicating that SRB developed regardless of the surface polarized as a source of H''0, generating H 2 S as a product of the anaerobic respiration. It was also determined that, without cathodic polarization, the conditions are not enough to reduce the H* generated by the H 2 S dissociation (pd is not susceptible to corrosion at this condition). On the other hand, cathodic polarization increased the permeation current, which was associated with the maximum enzymatic activity phase of the bacteria. (Author) 8 refs

Permeation of supercritical carbon dioxide through polymeric hollow fiber membranes

NARCIS (Netherlands)

Patil, V.E.; Broeke, van den L.J.P.; Vercauteren, F.F.; Keurentjes, J.T.F.

2006-01-01

Permeation of carbon dioxide was measured for two types of composite polymeric hollow fiber membranes for feed pressures up to 18 MPa at a temp. of 313 K. support membrane. The membranes consist of a polyamide copolymer (IPC) layer or a poly(vinyl alc.) (PVA) layer on top of a polyethersulfone

The influence of corneocyte structure on the interpretation of permeation profiles of nanoparticles across skin

Energy Technology Data Exchange (ETDEWEB)

Pinheiro, T. [LFI, Instituto Tecnologico Nuclear, and Centro de Fisica Nuclear, Universidade Lisboa E.N. 10, 2685-953 Sacavem (Portugal)]. E-mail: murmur@itn.pt; Pallon, J. [Lund Institute of Technology, Physics Department, Lund University, Lund (Sweden)]. E-mail: Jan.Pallon@pixe.lth.se; Alves, L.C. [LFI, Instituto Tecnologico Nuclear, and Centro de Fisica Nuclear, Universidade Lisboa E.N. 10, 2685-953 Sacavem (Portugal)]. E-mail: lcalves@itn.pt; Verissimo, A. [LFI, Instituto Tecnologico Nuclear, and Centro de Fisica Nuclear, Universidade Lisboa E.N. 10, 2685-953 Sacavem (Portugal)]. E-mail: averissimo@vims.edu; Filipe, P. [Departamento Dermatologia, Hospital Sta. Maria, Lisbon (Portugal)]. E-mail: pfilipe@fm.ul.pt; Silva, J.N. [Departamento Dermatologia, Hospital Sta. Maria, Lisbon (Portugal)]. E-mail: maiasilva@fm.ul.pt; Silva, R. [Departamento Dermatologia, Hospital Sta. Maria, Lisbon (Portugal)]. E-mail: rpalminhas@netcabo.pt

2007-07-15

The permeability of skin to nanoparticles of titanium dioxide (TiO{sub 2}) used in sunscreens as a reflector of the UV wavelengths of sunlight, was examined using nuclear microscopy techniques. Special attention was given to the permeation characteristics of these nanoparticles across the outer layers of skin, the stratum corneum, in healthy and psoriatic skin condition. Aspects that may influence the interpretation of results such as sample preparation difficulties and skin condition were focused. Sample preparation can damage the integrity of the corneocyte layers inducing unwanted artefacts that may bias the evaluation of results. Irradiation conditions may also introduce distortions in the labile structures of human skin. Skin condition, such as loss of corneocyte cohesion occurring in psoriasis also influence the permeation profile of the nanoparticles. Weighing and accounting for these features in the examination of skin by nuclear microscopy is crucial to accurately assess the TiO{sub 2} nanoparticles permeation depth.

Evaluation of γ-cyclodextrin effect on permeation of lipophilic drugs: application of cellophane/fused octanol membrane.

Science.gov (United States)

Muankaew, Chutimon; Jansook, Phatsawee; Loftsson, Thorsteinn

2017-06-01

According to the Biopharmaceutics Classification System, oral bioavailability of drugs is determined by their aqueous solubility and the ability of the dissolved drug molecules to permeate lipophilic biological membranes. Similarly topical bioavailability of ophthalmic drugs is determined by their solubility in the aqueous tear fluid and their ability to permeate the lipophilic cornea. Enabling pharmaceutical excipients such as cyclodextrins can have profound effect on the drug bioavailability. However, to fully appreciate such enabling excipients, the relationship between their effects and the physicochemical properties of the permeating drug needs to be known. In this study, the permeation enhancing effect of γ-cyclodextrin (γCD) on saturated drug solutions containing hydrocortisone (HC), irbesartan (IBS), or telmisartan (TEL) was evaluated using cellophane and fused cellulose-octanol membranes in a conventional Franz diffusion cell system. The flux (J), the flux ratio (J R ) and the apparent permeability coefficients (P app ) demonstrate that γCD increases drug permeability. However, its efficacy depends on the drug properties. Addition of γCD increased P app of HC (unionized) and IBS (partially ionized) through the dual membrane but decreased the P app of TEL (fully ionized) that displays low complexation efficacy. The dual cellophane-octanol membrane system was simple to use and gave reproducible results.

Catalytic thermal decomposition of polyethylene determined by thermogravimetric treatment

International Nuclear Information System (INIS)

Nisar, J.; Khan, M.S.; Khan, M.A.

2014-01-01

In this study low density polyethylene (LDPE) has been studied by thermogravimetric analysis (TGA) using commercially available oxides as catalysts. TGA experiments were used to evaluate the activity of different catalysts on low density polyethylene (LDPE) degradation and to study the effect in terms of type and amount of catalyst used. All the catalysts used improved the pyrolysis of LDPE. The reaction rates were found to increase with increase in amount of catalyst. Among the catalysts used, alumina acidic active catalyst performed better at all four fractions. Moreover, alumina acidic active reduced weight loss temperature better than others tested catalysts. The effect of alumina neutral catalyst on the pyrolysis of LDPE is less pronounced due to its small surface area and pore size. The effect of these catalysts showed that surface area, number of acidic sites and pore size were found as the key factors for the energy efficient degradation of polymers. (author)

Preparation, Characterization and Permeation Behavior of Poly(methyl acrylate-Poly(dimethyl siloxane-Poly(methyl acrylate Block Copolymer/Poly(vinyl acetate Blend Membranes

Directory of Open Access Journals (Sweden)

Mohammad Ali Semsarzadeh

2015-03-01

Full Text Available Structure of polymeric materials is of the most important factors in determination of the characteristics and properties of the membranes. Various research and developments on polymeric membranes confirm the direct correlation between structure-properties of polymeric membranes. In this research, the structural outcome of poly(methyl acrylate-poly(dimethyl siloxane-poly(methyl acrylate/poly(vinyl acetate blend membranes and its relationship with gas permeation behavior of the blends were investigated. The flexible block copolymer of poly(methyl acrylate-poly(dimethyl siloxane-poly(methyl acrylate (PMA-PDMS-PMA was synthesized via atom transfer radical polymerization. Morphology and chemical structure of the synthesized block copolymer was investigated by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, X-ray diffraction analysis, differential scanning calorimetry and scanning electron microscopy. Blend membranes of PMA-PDMS-PMA and poly(vinyl acetate (PVAc were prepared by solution casting method in different compositions. By adding poly(vinyl acetate to PMA-PDMS-PMA block copolymer, the selectivity of the membranes for carbon dioxide/methane pair gases were increased by 55%. Fractional free volume (an indication of chain packing efficiency in blend membranes and dielectric constant (an indication of the molar volume and molar polarization of the blend membranes were obtained as the factors reflected the microstructural effect of PMA-PDMS-PMA and PVAc blend membranes. The efforts were directed toward expressing more precise structure-properties relationship of PMA-PDMS-PMA/PVAc blend membranes. The experimental permeability values of the blend membranes reported in this research were compared with the modified logarithmic model. The modified logarithmic model was evaluated for other blend membranes.

Tritium inventory and permeation in liquid breeder blankets

International Nuclear Information System (INIS)

Reiter, F.

1990-01-01

This report reviews studies of the transport of hydrogen isotopes in the DEMO relevant water-cooled Pb-17Li blanket to be tested in NET and in a self-cooled blanket which uses Pb-17Li or Flibe as a liquid breeder material and V or Fe as a first wall material. The time dependences of tritium inventory and permeation in these blankets and of deuterium and tritium recycling in the self-cooled blanket are presented and discussed

Preparation of Silica Nanoparticles Loaded with Nootropics and Their In Vivo Permeation through Blood-Brain Barrier

OpenAIRE

Jampilek, Josef; Zaruba, Kamil; Oravec, Michal; Kunes, Martin; Babula, Petr; Ulbrich, Pavel; Brezaniova, Ingrid; Opatrilova, Radka; Triska, Jan; Suchy, Pavel

2015-01-01

The blood-brain barrier prevents the passage of many drugs that target the central nervous system. This paper presents the preparation and characterization of silica-based nanocarriers loaded with piracetam, pentoxifylline, and pyridoxine (drugs from the class of nootropics), which are designed to enhance the permeation of the drugs from the circulatory system through the blood-brain barrier. Their permeation was compared with non-nanoparticle drug substances (bulk materials) by means of an i...

Permeation studies of novel terbinafine formulations containing hydrophobins through human nails in vitro.

Science.gov (United States)

Vejnovic, Ivana; Huonder, Cornelia; Betz, Gabriele

2010-09-15

Existing treatments of onychomycosis are not satisfactory. Oral therapies have many side effects and topical formulations are not able to penetrate into the human nail plate and deliver therapeutical concentrations of active agent in situ. The purpose of the present study was to determine the amount of terbinafine, which permeates through the human nail plate, from liquid formulations containing enhancers, namely hydrophobins A-C in the concentration of 0.1% (w/v). The used reference solution contained 10% (w/v) of terbinafine in 60% (v/v) ethanol/water without enhancer. Permeability studies have been performed on cadaver nails using Franz diffusion cells modified to mount nail plates and filled with 60% (v/v) ethanol/water in the acceptor chamber. Terbinafine was quantitatively determined by HPLC. The amount of terbinafine remaining in the nail was extracted by 96% ethanol from pulverized nail material after permeation experiment and presented as percentage of the dry nail weight before the milling test. Permeability coefficient (PC) of terbinafine from reference solution was determined to be 1.52E-10 cm/s. Addition of hydrophobins improved PC in the range of 3E-10 to 2E-9 cm/s. Remaining terbinafine reservoir in the nail from reference solution was 0.83% (n=2). An increase of remaining terbinafine reservoir in the nail was observed in two out of three tested formulations containing hydrophobins compared to the reference. In all cases, known minimum inhibitory concentration of terbinafine for dermatophytes (0.003 microg/ml) has been exceeded in the acceptor chamber of the diffusion cells. All tested proteins (hydrophobins) facilitated terbinafine permeation after 10 days of permeation experiment, however one of them achieved an outstanding enhancement factor of 13.05 compared to the reference. Therefore, hydrophobins can be included in the list of potential enhancers for treatment of onychomycosis. Copyright 2010 Elsevier B.V. All rights reserved.

Modeling the concentration-dependent permeation modes of the KcsA potassium ion channel.

Science.gov (United States)

Nelson, Peter Hugo

2003-12-01

The potassium channel from Streptomyces lividans (KcsA) is an integral membrane protein with sequence similarity to all known potassium channels, particularly in the selectivity filter region. A recently proposed model for ion channels containing either n or (n-1) single-file ions in their selectivity filters [P. H. Nelson, J. Chem. Phys. 177, 11396 (2002)] is applied to published KcsA channel K+ permeation data that exhibit a high-affinity process at low concentrations and a low-affinity process at high concentrations [M. LeMasurier et al., J. Gen. Physiol. 118, 303 (2001)]. The kinetic model is shown to provide a reasonable first-order explanation for both the high- and low-concentration permeation modes observed experimentally. The low-concentration mode ([K+]200 mM) has a 200-mV dissociation constant of 1100 mM and a conductance of 500 pS. Based on the permeation model, and x-ray analysis [J. H. Morais-Cabral et al., Nature (London) 414, 37 (2001)], it is suggested that the experimentally observed K+ permeation modes correspond to an n=3 mechanism at high concentrations and an n=2 mechanism at low concentrations. The ratio of the electrical dissociation distances for the high- and low-concentration modes is 3:2, also consistent with the proposed n=3 and n=2 modes. Model predictions for K+ channels that exhibit asymmetric current-voltage (I-V) curves are presented, and further validation of the kinetic model via molecular simulation and experiment is discussed. The qualitatively distinct I-V characteristics exhibited experimentally by Tl+, NH+4, and Rb+ ions at 100 mM concentration can also be explained using the model, but more extensive experimental tests are required for quantitative validation of the model predictions.

Selective Permeation and Organic Extraction of Recombinant Green Fluorescent Protein (gfpuv from Escherichia coli

Directory of Open Access Journals (Sweden)

Ishii Marina

2002-04-01

Full Text Available Abstract Background Transformed cells of Escherichia coli DH5-α with pGFPuv, induced by IPTG (isopropyl-β-d-thiogalactopyranoside, express the green fluorescent protein (gfpuv during growth phases. E. coli subjected to the combination of selective permeation by freezing/thawing/sonication cycles followed by the three-phase partitioning extraction (TPP method were compared to the direct application of TPP to the same culture of E. coli on releasing gfpuv from the over-expressing cells. Material and Methods Cultures (37°C/100 rpm/ 24 h; μ = 0.99 h-1 - 1.10 h-1 of transformed (pGFP Escherichia coli DH5-α, expressing the green fluorescent protein (gfpuv, absorbance at 394 nm and emission at 509 nm were sonicated in successive intervals of sonication (25 vibrations/pulse to determine the maximum amount of gfpuv released from the cells. For selective permeation, the transformed previously frozen (-75°C cells were subjected to three freeze/thaw (-20°C/ 0.83°C/min cycles interlaid by sonication (3 pulses/ 6 seconds/ 25 vibrations. The intracellular permeate with gfpuv in extraction buffer (TE solution (25 mM Tris-HCl, pH 8.0, 1 mM β-mercaptoethanol β-ME, 0.1 mM PMSF was subjected to the three-phase partitioning (TPP method with t-butanol and 1.6 M ammonium sulfate. Sonication efficiency was verified on the application to the cells previously treated by the TPP method. The intra-cell releases were mixed and eluted through methyl HIC column with a buffer solution (10 mM Tris-HCl, 10 mM EDTA, pH 8.0. Results The sonication maximum released amount obtained from the cells was 327.67 μg gfpuv/mL (20.73 μg gfpuv/mg total proteins – BSA, after 9 min of treatment. Through the selective permeation by three repeated freezing/thawing/sonication cycles applied to the cells, a close content of 241.19 μg gfpuv/mL (29.74 μg gfpuv/mg BSA was obtained. The specific mass range of gfpuv released from the same cultures, by the three-phase partitioning (TPP

Surface condition effects on tritium permeation through the first wall of a water-cooled ceramic breeder blanket

Energy Technology Data Exchange (ETDEWEB)

Zhou, H.-S. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei (China); Xu, Y.-P.; Liu, H.-D. [Science Island Branch of Graduate School, University of Science and Technology of China, P.O. Box 1126, Hefei (China); Liu, F.; Li, X.-C.; Zhao, M.-Z.; Qi, Q.; Ding, F. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei (China); Luo, G.-N., E-mail: gnluo@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei (China); Science Island Branch of Graduate School, University of Science and Technology of China, P.O. Box 1126, Hefei (China); Hefei Center for Physical Science and Technology, P.O. Box 1126, Hefei (China); Hefei Science Center of Chinese Academy of Science, P.O. Box 1126, Hefei (China)

2016-11-01

Highlights: • We investigate surface effects on T transport through the first wall. • We solve transport equations with various surface conditions. • The RAFMs walls w/and w/o W exhibit different T permeation behavior. • Diffusion in W has been found to be the rate-limiting step. - Abstract: Plasma-driven permeation of tritium (T) through the first wall of a water-cooled ceramic breeder (WCCB) blanket may raise safety and other issues. In the present work, surface effects on T transport through the first wall of a WCCB blanket have been investigated by theoretical calculation. Two types of wall structures, i.e., reduced activation ferritic/martensitic steels (RAFMs) walls with and without tungsten (W) armor, have been analyzed. Surface recombination is assumed to be the boundary condition for both the plasma-facing side and the coolant side. It has been found that surface conditions at both sides can affect T permeation flux and inventory. For the first wall using W as armor material, T permeation is not sensitive to the plasma-facing surface conditions. Contamination of the surfaces will lead to higher T inventory inside the first wall.

Permeation of sumatriptan succinate across human skin using multiple types of self-dissolving microneedle arrays fabricated from sodium hyaluronate.

Science.gov (United States)

Wu, Dan; Katsumi, Hidemasa; Quan, Ying-Shu; Kamiyama, Fumio; Kusamori, Kosuke; Sakane, Toshiyasu; Yamamoto, Akira

2016-09-01

Available formulations of sumatriptan succinate (SS) have low bioavailability or are associated with site reactions. We developed various types of self-dissolving microneedle arrays (MNs) fabricated from sodium hyaluronate as a new delivery system for SS and evaluated their skin permeation and irritation in terms of clinical application. In vitro permeation studies with human skin, physicochemical properties (needle length, thickness and density), and penetration enhancers (glycerin, sodium dodecyl sulfate and lauric acid diethanolamide) were investigated. SS-loaded high-density MNs of 800 µm in length were the optimal formulation and met clinical therapeutic requirements. Penetration enhancers did not significantly affect permeation of SS from MNs. Optical coherence tomography images demonstrated that SS-loaded high-density MNs (800 µm) uniformly created drug permeation pathways for the delivery of SS into the skin. SS-loaded high-density MNs induced moderate primary skin irritations in rats, but the skin recovered within 72 h of removal of the MNs. These findings suggest that high-density MNs of 800 µm in length are an effective and promising formulation for transdermal delivery of SS. To our knowledge, this is the first report of SS permeation across human skin using self-dissolving MNs.

Low-Volatility Agent Permeation (LVAP) Verification and Validation Report

Science.gov (United States)

2015-05-01

custody procedures were obtained from the ISO / IEC 17025 :2005 standard13 as well as the current version of Permeation and Analytical Solutions Branch...Testing and Calibration Laboratories; ISO / IEC 17025 :2005; International Organization for Standardization: Geneva, Switzerland, 2005. 14. Box, G.E...ECBC, as detailed in Section 6.4.4 The International Organization for Standardization ( ISO ) method, 5725-3 (1994), was used to calculate the standard

Plasma chromatography

International Nuclear Information System (INIS)

Anon.

1984-01-01

This book examines the fundamental theory and various applications of ion mobility spectroscopy. Plasma chromatography developed from research on the diffusion and mobility of ions. Topics considered include instrument design and description (e.g., performance, spectral interpretation, sample handling, mass spectrometry), the role of ion mobility in plasma chromatography (e.g., kinetic theory of ion transport), atmospheric pressure ionization (e.g., rate equations), the characterization of isomers by plasma chromatography (e.g., molecular ion characteristics, polynuclear aromatics), plasma chromatography as a gas chromatographic detection method (e.g., qualitative analysis, continuous mobility monitoring, quantitative analysis), the analysis of toxic vapors by plasma chromatography (e.g., plasma chromatograph calibration, instrument control and data processing), the analysis of semiconductor devices and microelectronic packages by plasma chromatography/mass spectroscopy (e.g., analysis of organic surface contaminants, analysis of water in sealed electronic packages), and instrument design and automation (hardware, software)

Tritium permeation behavior through pyrolytic carbon in tritium production using high-temperature gas-cooled reactor for fusion reactors

Directory of Open Access Journals (Sweden)

H. Ushida

2016-12-01

Full Text Available Under tritium production method using a high-temperature gas-cooled reactor loaded Li compound, Li compound has to be coated by ceramic materials in order to suppress the spreading of tritium to the whole reactor. Pyrolytic carbon (PyC is a candidate of the coating material because of its high resistance for gas permeation. In this study, hydrogen permeation experiments using a PyC-coated isotropic graphite tube were conducted and hydrogen diffusivity, solubility and permeability were evaluated. Tritium permeation behavior through PyC-coated Li compound particles was simulated by using obtained data. Hydrogen permeation flux through PyC in a steady state is proportional to the hydrogen pressure and is larger than that through Al2O3 which is also candidate coating material. However, total tritium leak within the supposed reactor operation period through the PyC-coated Li compound particles is lower than that through the Al2O3-coated ones because the hydrogen absorption capacity in PyC is considerably larger than that in Al2O3.

Tailored nanostructured platforms for boosting transcorneal permeation: Box-Behnken statistical optimization, comprehensive in vitro, ex vivo and in vivo characterization.

Science.gov (United States)

Elsayed, Ibrahim; Sayed, Sinar

2017-01-01

Ocular drug delivery systems suffer from rapid drainage, intractable corneal permeation and short dosing intervals. Transcorneal drug permeation could increase the drug availability and efficiency in the aqueous humor. The aim of this study was to develop and optimize nanostructured formulations to provide accurate doses, long contact time and enhanced drug permeation. Nanovesicles were designed based on Box-Behnken model and prepared using the thin film hydration technique. The formed nanodispersions were evaluated by measuring the particle size, polydispersity index, zeta potential, entrapment efficiency and gelation temperature. The obtained desirability values were utilized to develop an optimized nanostructured in situ gel and insert. The optimized formulations were imaged by transmission and scanning electron microscopes. In addition, rheological characters, in vitro drug diffusion, ex vivo and in vivo permeation and safety of the optimized formulation were investigated. The optimized insert formulation was found to have a relatively lower viscosity, higher diffusion, ex vivo and in vivo permeation, when compared to the optimized in situ gel. So, the lyophilized nanostructured insert could be considered as a promising carrier and transporter for drugs across the cornea with high biocompatibility and effectiveness.

Tailored nanostructured platforms for boosting transcorneal permeation: Box–Behnken statistical optimization, comprehensive in vitro, ex vivo and in vivo characterization

Science.gov (United States)

Elsayed, Ibrahim; Sayed, Sinar

2017-01-01

Ocular drug delivery systems suffer from rapid drainage, intractable corneal permeation and short dosing intervals. Transcorneal drug permeation could increase the drug availability and efficiency in the aqueous humor. The aim of this study was to develop and optimize nanostructured formulations to provide accurate doses, long contact time and enhanced drug permeation. Nanovesicles were designed based on Box–Behnken model and prepared using the thin film hydration technique. The formed nanodispersions were evaluated by measuring the particle size, polydispersity index, zeta potential, entrapment efficiency and gelation temperature. The obtained desirability values were utilized to develop an optimized nanostructured in situ gel and insert. The optimized formulations were imaged by transmission and scanning electron microscopes. In addition, rheological characters, in vitro drug diffusion, ex vivo and in vivo permeation and safety of the optimized formulation were investigated. The optimized insert formulation was found to have a relatively lower viscosity, higher diffusion, ex vivo and in vivo permeation, when compared to the optimized in situ gel. So, the lyophilized nanostructured insert could be considered as a promising carrier and transporter for drugs across the cornea with high biocompatibility and effectiveness. PMID:29133980

Corrosion and hydrogen permeation of A216 Grade WCA steel in hydrothermal magnesium-containing brines

International Nuclear Information System (INIS)

Haberman, J.H.; Frydrych, D.J.; Westerman, R.E.

1988-03-01

Corrosion rates determined at 1 month in 150/degree/C brine increased with magnesium concentration. The structure of the corrosion product, as determined by x-ray diffraction, depended upon the magnesium concentration. In brines with less than 10,000 ppM magnesium, the primary corrosion product had a spinel structure characteristic of magnetite or magnesioferrite. In brines containing magnesium concentrations greater than 20,000 ppM, the primary corrosion product had the amakinite structure characteristic of a complex iron-magnesium hydroxide. The high corrosion rates observed in brines containing high magnesium concentrations suggest that the corrosion products having the amakinite structure is less protective than corrosion products having the spinel structure. Corrosion rates in high-magnesium (inclusion) brine determined over a 6-month test duration were essentially constant. Hydrogen permeation rates observed in exposing mild steel to high-Mg/sup 2/plus// brine at 150/degree/C could be potentially damaging to a mild steel waste package container. The rate of hydrogen permeation was proportional to the brine flow rate in the autoclave. Thiourea additions to the brine increased the hydrogen permeation rate; sulfate and bromide ion additions did not. The maximum gaseous hydrogen pressure attainable is not known (based on 3Fe /plus/ 4H 2 O /plus/ Fe(sub 3)O /plus/ 4H 2 , would be /approximately/900 atmospheres), and the dependence of permeation rate on temperature is not known. 8 refs., 13 figs., 3 tabs

A novel microdialysis-dissolution/permeation system for testing oral dosage forms

DEFF Research Database (Denmark)

Fong, Sophia Yui Kau; Poulsen, Jessie; Brandl, Martin

2016-01-01

A novel microdialysis-dissolution/permeation (M-D/P) system was developed for the biopharmaceutical assessment of oral drug formulations. This system consists of a side-by-side diffusion chamber, a microdialysis unit fixed within the dissolution chamber for continuous sampling, and a biomimetic P...

Effect of helium irradiation on deuterium permeation behavior in tungsten

Energy Technology Data Exchange (ETDEWEB)

Uemura, Yuki; Sakurada, Shodai; Fujita, Hiroe; Azuma, Keisuke; Zhou, Quilai [Graduate School of Science & Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, 422-8529 Japan (Japan); Hatano, Yuji [Hydrogen Isotope Research Center, University of Toyama, 3190 Gofuku, Toyama, 930-8555 Japan (Japan); Yoshida, Naoaki; Watanabe, Hideo [Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka, 816-8580 Japan (Japan); Oyaizu, Makoto; Isobe, Kanetsugu [National Institutes for Quantum and Radiological Science and Technology, 2166 Obuchi, Rokkasho, Aomori, 039-3212 Japan (Japan); Shimada, Masashi [Idaho National Laboratory, 1955 N. Fremont Avenue, Idaho Falls, ID 83415 (United States); Buchenauer, Dean; Kolasinski, Robert [Sandia National Laboratories, Chemistry, Combustion and Materials Center, Livermore, CA 94550 (United States); Chikada, Takumi [Graduate School of Science & Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, 422-8529 Japan (Japan); Oya, Yasuhisa, E-mail: oya.yasuhisa@shizuoka.ac.jp [Graduate School of Science & Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, 422-8529 Japan (Japan)

2017-07-15

In this study, we measured deuterium (D) gas-driven permeation through tungsten (W) foils that had been pre-damaged by helium ions (He{sup +}). The goal of this work was to determine how ion-induced damage affects hydrogen isotope permeation. At 873 K, the D permeability for W irradiated by 3.0 keV He{sup +} was approximately one order of magnitude lower than that for un-damaged W. This difference diminished with increasing temperature. Even after heating to 1173 K, the permeability returned to less than half of the value measured for un-damaged W. We propose that this is due to nucleation of He bubbles near the surface which potentially serve as a barrier to diffusion deeper into the bulk. Exposure at higher temperatures shows that the D permeability and diffusion coefficients return to levels observed for undamaged material. It is possible that these effects are linked to annealing of defects introduced by ion damage, and whether the defects are stabilized by the presence of trapped He.

Characteristics and kinetic studies of Hydrilla verticillata pyrolysis via thermogravimetric analysis.

Science.gov (United States)

Hu, Zhiquan; Chen, Zhihua; Li, Genbao; Chen, Xiaojuan; Hu, Mian; Laghari, Mahmood; Wang, Xun; Guo, Dabin

2015-10-01

The pyrolysis characteristics and kinetic of Hydrilla verticillata (HV) have been investigated using non-isothermal thermogravimetric analysis. The results showed that the pyrolysis behavior of HV can be divided into two independent stages. The kinetics of Stage I was investigated using a distributed activation energy model (DAEM) with discrete 99 first-order reactions. Stage II was an independent stage which corresponds to the decomposition of calcium oxalate, whose kinetics was studied using iso-conversional method together with compensation effect and master-plots method. The activation energies ranged from 92.39 to 506.17 and 190.42 to 222.48 kJ/mol for the first and second stages respectively. Calculated data gave very good fit to the experimental data. Copyright © 2015 Elsevier Ltd. All rights reserved.

Oxygen permeation flux through La1-ySryFeO3 limited by the carbon monoxide oxidation rate

NARCIS (Netherlands)

van Hassel, B.A.; van Hassel, B.A.; ten Elshof, Johan E.; Bouwmeester, Henricus J.M.

1995-01-01

The oxygen permeation flux through La1-ySryFeO3-δ (y = 0.1, 0.2) in a large oxygen partial pressure gradient (air/CO, CO2 mixture) was found to be limited by the carbon monoxide oxidation rate at the low oxygen partial pressure side of the membrane. The oxygen permeation flux through the membrane

Automation of a McBain-Bakr-type thermogravimetric analyzer using a digital image correlation technique

International Nuclear Information System (INIS)

Trexler, M.D.; Sanders, T.H. Jr.; Singh, P.M.

2006-01-01

Thermogravimetric analysis was used to obtain corrosion kinetics data for several materials in high-temperature environments. A thermogravimetric analyzer has been developed that uses a McBain-Bakr quartz spring balance in conjunction with a digital image acquisition and analysis package to accurately characterize materials through image correlation. This provides a new method for automatically measuring mass changes continuously with a variable resolution depending on the spring component. The decomposition of calcium oxalate was used to verify the validity of the technique. The results show two reactions, whose reaction temperatures were determined by the intercept method, upon heating to 650 deg. C. The mass loss at the first reaction temperature, 200 deg. C, was 20% and a 30% loss was observed at 500 deg. C. Comparison of the experimentally obtained results with those of other researchers who used commercial instruments suggests that the method of using digital image analysis in conjunction with a spring to monitor mass change is a viable and accurate replacement for automatic electrobalances and cathetometers for thermal analysis of materials. Additional comparison between corrosion tests performed on SA210 steel in H 2 S using both a commercial thermobalance and the developed technique confirmed that high-temperature corrosion can be monitored accurately with the proposed method

Pervaporation membrane bioreactor with permeate fractional condensation and mechanical vapor compression for energy efficient ethanol production

International Nuclear Information System (INIS)

Fan, Senqing; Xiao, Zeyi; Li, Minghai; Li, Sizhong

2016-01-01

Graphical abstract: Pervaporation membrane bioreactor with permeate partial condensation and mechanical vapor compression is developed for an energy efficient ethanol production. - Highlights: • PVMBR-MVC for energy efficient ethanol production. • Process separation factor of 20–44 for ethanol achieved by fractional condensation. • Energy production of 20.25 MJ and hourly energy production of 56.25 kJ/h achieved. • Over 50% of energy saved in PVMBR-MVC compared with PVMBR-LTC. • Integrated heat pump with COP of 7–9 for the energy recovery of the permeate. - Abstract: Improved process separation factor and heat integration are two key issues to increase the energy efficiency of ethanol production in a pervaporation membrane bioreactor (PVMBR). A PVMBR with permeate fractional condensation and mechanical vapor compression was developed for energy efficient ethanol production. A condensation model based on the mass balance and thermodynamic equilibrium in the partial vacuum condenser was developed for predicting the purification performance of the permeate vapor. Three runs of ethanol fermentation-pervaporation experiment were carried out and ethanol concentration of higher than 50 wt% could be achieved in the final condensate, with the separation factor of the process for ethanol increased to 20. Ethanol production could be enhanced in the bioreactor and 17.1 MJ of the energy could be produced in per liter of fermentation broth, owing to 27.0 MJ/kg heating value of the recovered ethanol. Compared with the traditional pervaporation process with low temperature condensation for ethanol production, 50% of the energy would be saved in the process. The energy consumption would be further reduced, if the available energy of the permeate vapor was utilized by integrating the mechanical vapor compression heat pump.

Microstructural Study on Oxygen Permeated Arc Beads

Directory of Open Access Journals (Sweden)

Kuan-Heng Liu

2015-01-01

Full Text Available We simulated short circuit of loaded copper wire at ambient atmosphere and successfully identified various phases of the arc bead. A cuprous oxide flake was formed on the surface of the arc bead in the rapid solidification process, and there were two microstructural constituents, namely, Cu-κ eutectic structure and solutal dendrites. Due to the arc bead formed at atmosphere during the local equilibrium solidification process, the phase of arc bead has segregated to the cuprous oxide flake, Cu-κ eutectic, and Cu phase solutal dendrites, which are the fingerprints of the arc bead permeated by oxygen.

APPLICATION OF A SURFACE-RENEWAL MODEL TO PERMEATE-FLUX DATA FOR CONSTANTPRESSURE CROSS-FLOW MICROFILTRATION WITH DEAN VORTICES

Directory of Open Access Journals (Sweden)

G. Idan

2015-06-01

Full Text Available AbstractThe introduction of flow instabilities into a microfiltration process can dramatically change several elements such as the surface-renewal rate, permeate flux, specific cake resistance, and cake buildup on the membrane in a positive way. A recently developed surface-renewal model for constant-pressure, cross-flow microfiltration (Hasan et al., 2013 is applied to the permeate-flux data reported by Mallubhotla and Belfort (1997, one set of which included flow instabilities (Dean vortices while the other set did not. The surface-renewal model has two forms - the complete model and an approximate model. For the complete model, the introduction of vortices leads to a 53% increase in the surface-renewal rate, which increases the limiting (i.e., steady-state permeate flux by 30%, decreases the specific cake resistance by 14.5% and decreases the limiting cake mass by 15.5% compared to operation without vortices. For the approximate model, a 50% increase in the value of surface renewal rate is shown due to vortices, which increases the limiting permeate flux by 30%, decreases the specific cake resistance by 10.5% and decreases the limiting cake mass by 13.7%. The cake-filtration version of the critical-flux model of microfiltration (Field et al., 1995 is also compared against the experimental permeate-flux data of Mallubhotla and Belfort (1997. Although this model can represent the data, the quality of its fit is inferior compared to that of the surface-renewal model.

Thermal effect of periodical bakeout on tritium inventory in first wall and permeation to coolant in reactor life

International Nuclear Information System (INIS)

Nakahara, Katsuhiko

1989-01-01

In view of safety, it is very important to control the tritium inventory in first walls and permeation to the coolant. A time-dependent diffusion and temperature calculation code, TPERM, was developed. Using this code, a numerical study on the long term effects of the bakeout temperature on tritium inventory and tritium permeation to the coolant was made. In this study, an FER type first wall (stainless steel) was considered and a cyclic operation (one cycle includes a plasma burn phase and a bakeout phase) was assumed. The results are as follows: (i) There is almost no difference in the tritium inventory in the first wall between the operation with 150 0 C-bakeout and the continuous burning operation (without bakeout). In both cases there is not tritium permeation to the coolant at 5 years' integrated burn time. The 150 0 C-bakeout is effective to release tritium in the surface (to 0.1 mm depth) region on the plasma side, but it is not effective to decrease the tritium inventory over the reactor life. (ii) To decrease the tritium inventory, a bakeout at a temperature higher than 150 0 C is necessary. But a high temperature bakeout causes earlier tritium permeation to the coolant. (iii) From these results it is suggested that the decrease the tritium inventory over the reactor life by bakeout, some form of protection against tritium permeation or a decontamination device in the cooling (or bakeout) system becomes necessary. (orig.)

Combustion characteristics of Malaysian oil palm biomass, sub-bituminous coal and their respective blends via thermogravimetric analysis (TGA).

Science.gov (United States)

Idris, Siti Shawalliah; Rahman, Norazah Abd; Ismail, Khudzir

2012-11-01

The combustion characteristics of Malaysia oil palm biomass (palm kernel shell (PKS), palm mesocarp fibre (PMF) and empty fruit bunches (EFB)), sub-bituminous coal (Mukah Balingian) and coal/biomass blends via thermogravimetric analysis (TGA) were investigated. Six weight ratios of coal/biomass blends were prepared and oxidised under dynamic conditions from temperature 25 to 1100°C at four heating rates. The thermogravimetric analysis demonstrated that the EFB and PKS evolved additional peak besides drying, devolatilisation and char oxidation steps during combustion. Ignition and burn out temperatures of blends were improved in comparison to coal. No interactions were observed between the coal and biomass during combustion. The apparent activation energy during this process was evaluated using iso-conversional model free kinetics which resulted in highest activation energy during combustion of PKS followed by PMF, EFB and MB coal. Blending oil palm biomass with coal reduces the apparent activation energy value. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of hypothyroidism on vascular 125I-albumin permeation and blood flow in rats

International Nuclear Information System (INIS)

Tilton, R.G.; Pugliese, G.; Chang, K.; Speedy, A.; Province, M.A.; Kilo, C.; Williamson, J.R.

1989-01-01

Effects of hypothyroidism on vascular 125I-albumin permeation and on blood flow were assessed in multiple tissues of male Sprague-Dawley rats rendered hypothyroid by dietary supplementation with 0.5% (wt/wt) 2-thiouracil or by thyroidectomy. In both thiouracil-treated and thyroidectomized rats, body weights, kidney weight, arterial blood pressure, and pulse rate were decreased significantly v age-matched controls. After 10 to 12 weeks of thiouracil treatment, 125I-albumin permeation was increased significantly in the kidney, aorta, eye (anterior uvea, choroid, retina), skin, and new granulation tissue, remained unchanged in brain, sciatic nerve, and heart, and was decreased in forelimb skeletal muscle. A similar pattern was observed in thyroidectomized rats, except that increases in 125I-albumin permeation for all tissues were smaller than those observed in thiouracil-treated rats, and 125I-albumin permeation in retina did not differ from controls. In both thiouracil-treated and thyroidectomized rats, changes in blood flow (assessed with 15-microns, 85Sr-labeled microspheres) relative to the decrease in arterial blood pressure were indicative of a decrease in regional vascular resistance except in the choroid and in the kidney, in which vascular resistance was increased significantly. Glomerular filtration rate was decreased, but filtration fraction and urinary excretion of albumin remained unchanged by thiouracil treatment and thyroidectomy. These results indicate that vascular hemodynamics and endothelial cell barrier functional integrity are modulated in many different tissues by the thyroid. In view of the correspondence of hypothyroid- and diabetes-induced vascular permeability changes, these results raise the possibility that altered thyroid function in diabetes may play a role in the pathogenesis of diabetic vascular disease

Thermogravimetric analysis of the beryllium/steam reaction

Energy Technology Data Exchange (ETDEWEB)

Druyts, Frank E-mail: fdruyts@sckcen.be; Iseghem, Pierre van

2000-11-01

In view of the safety assessment of new fusion reactor designs, kinetic data are needed on the beryllium/steam reaction. Therefore, thermogravimetric analysis was used to determine the reactivity of beryllium in steam as a function of temperature, irradiation history and porosity of the samples. To this purpose, reference unirradiated S-200 VHP beryllium samples were compared with specimens irradiated in the BR2 reactor up to fast neutron fluences (E>1 MeV) of respectively 1.6x10{sup 21} n cm{sup -2} (resulting in a helium content of 300 appm He and a theoretical density of 99.9%) and 4x10{sup 22} n cm{sup -2} (21000 appm He, 97.2% theoretical density). Kinetics were parabolic for all tested beryllium types at 600 deg. C. At 700 deg. C, kinetics were parabolic for the unirradiated and irradiated 99.9% dense beryllium, and accelerating/linear for the irradiated 97.2% material. At 800 deg. C, all samples showed accelerating/linear behaviour. There was no influence of porosity on the reaction rate of beryllium in steam within the limited investigated density range, except at 700 deg. C, where the measured reaction rate for the irradiated 97.2% dense samples is an order of magnitude higher than for the irradiated 99.9% dense specimens.

Effect of Bile Salt on Permeation Characteristics of the Oral Mucosal ...

African Journals Online (AJOL)

An attempt was made to study the effect of bile salt [sodium glycocholate (SG)] as a permeation enhancer on mucoadhesive buccal patches of diltiazem hydrochloride (anti-anginal drug) using various polymers like hydroxypropyl methyl cellulosee (HPMC), Eudragit RL100, ethyl cellulose alone and in combination with PVP.

Prediction of Permeation Resistance of Protective Gloves, etc. from Solubility Parameters

DEFF Research Database (Denmark)

Henriksen, H. Risvig; Madsen, Jørgen Øgaard

1997-01-01

). A starting point was the authoritative conclusion (Coletta et al., 1978), that permeation in protective clothing could not be predicted. As a spin off, the predictive concept indicated that new types of polymers sometimes should be incorporated to reach a reasonable (long) breakthrough time and (low...

Dynamic dissolution-/permeation-testing of nano- and microparticle formulations of fenofibrate

DEFF Research Database (Denmark)

Sironi, Daniel; Rosenberg, Jörg; Bauer-Brandl, Annette

2017-01-01

-/ or nanoparticle-formulation was tested. Nondissolved nano-/microparticles served as a reservoir helping to maintain high levels of molecularly dissolved drug, which in turn caused high and constant permeation rates. The micelle-bound drug may also serve as a drug-reservoir, yet of subordinate importance as long...

Determination of factor of hydrogen permeation reduction (PRF) for different protective coatings over vanadium

International Nuclear Information System (INIS)

Afanasyev, S.; Kulsartov, T.; Shestakov, V.; Chikhray, Y.; Smith, D.

2002-01-01

Selection of structural materials for liquid-metal system as well as for another system and constructions of nuclear energy plants must be carried out and based on specified demands depending on conditions of these materials functioning. Specific demand is its compatibility with liquid metals. Design of reactors with liquid-metal coolant (Li, PbLi 17 ) which reproduces tritium arise additional demand to structural materials. This demand is a creation of structural material or protective barrier with minimum acceptable value of tritium permeation through itself or with maximum permeation reduction factor (PRF). Vanadium and vanadium alloys are supposed to be use as a blanket structural material in such nuclear energy plants. Worked out at first stage of studies vanadium coatings should have stability of its characteristics at temperature 800 deg. C under influence of hydrogen. Given work shows the experimental results on testing of protective coatings over vanadium: glass-ceramic coating and CaO-base coating. PRF for every coating and its changes depending on thermo-capacity of vanadium sample with coating was determined by method of hydrogen permeation. The results of experiments would be used at the development of cooling loops of reactor core protection with liquid-metal coolant

New experimental set-up and procedure for analyzing the dynamics of permeation of H2(g) across Pd-based metallic membranes

International Nuclear Information System (INIS)

Decaux, C.; Millet, P.; Decaux, C.

2006-01-01

Hydrogen permeation through metallic membranes is an industrial process used for purification purposes. Palladium-based alloys are generally used as permeation materials at operating temperatures above the critical value so that the metal-H system remains monophasic and that diffusion proceeds at sufficient rate. In state of the art systems, metallic membranes with typical thickness of a few tens of microns are used and rate limitation are generally attributed to atomic H transport by diffusion. Because of cost considerations, it is necessary to reduce the thickness of these membranes. In the micron thick range, surface contributions are expected to become rate determining, or at least to play an increasing role. Further, when the membrane is used on the exit side of a gas reformer to directly extract hydrogen, corrosion problems are expected to occur on the upstream side of the membrane. For all these reasons, there is a need to separately measure surface and bulk (diffusion) rate contributions to the overall permeation flux. A new experimental equipment has been specifically designed for this purpose. This setup can be operated in two different modes: for sorption or permeation experiments. In a typical sorption experiment, the metallic membrane is disposed in the reaction chamber and hydrogen is allowed to react from both side of the surface. This procedure allows the separate measurement of surface absorption and desorption resistances associated with the chemisorption step. In a typical permeation experiment, the membrane is mounted between two volume chambers, a pressurized hydrogen source reservoir and an empty sink reservoir. Initially, a difference of pressure is set between the two reservoirs. When the valve of the source tank is opened, H 2 (g) flows to the membrane and permeation proceeds until pressure reaches an equilibrium value. In both experimental configurations, gas pressure transients are synchronously sampled all along the experiment

Corneal permeation properties of a charged lipid nanoparticle carrier containing dexamethasone

Science.gov (United States)

Ban, Junfeng; Zhang, Yan; Huang, Xin; Deng, Guanghan; Hou, Dongzhi; Chen, Yanzhong; Lu, Zhufen

2017-01-01

Drug delivery carriers can maintain effective therapeutic concentrations in the eye. To this end, we developed lipid nanoparticles (L/NPs) in which the surface was modified with positively charged chitosan, which engaged in hydrogen bonding with the phospholipid membrane. We evaluated in vitro corneal permeability and release characteristics, ocular irritation, and drug dynamics of modified and unmodified L/NPs in aqueous humor. The size of L/NPs was uniform and showed a narrow distribution. Corneal permeation was altered by the presence of chitosan and was dependent on particle size; the apparent permeability coefficient of dexamethasone increased by 2.7 and 1.8 times for chitosan-modified and unmodified L/NPs, respectively. In conclusion, a chitosan-modified system could be a promising method for increasing the ocular bioavailability of unmodified L/NPs by enhancing their retention time and permeation into the cornea. These findings provide a theoretical basis for the development of effective drug delivery systems in the treatment of ocular disease. PMID:28243093

Cromatografia unificada Unified chromatography

Directory of Open Access Journals (Sweden)

Carin von Mühlen

2004-10-01

Full Text Available The scope of this study encompasses an overview of the principles of unified chromatography as well as the principles of chromatographic techniques as applied to unified systems, which include gas chromatography, liquid chromatography, supercritical fluid chromatography, high temperature and high pressure liquid chromatography, micro-liquid chromatography, enhanced fluidity chromatography, and solvating gas chromatography. Theoretical considerations and individual instrumental parameters such as mobile phase, sample introduction system, columns, and detection system are also discussed. Future applications of this separation approach are discussed.

The permeation of tritium through 316L stainless steel with multiple coatings

International Nuclear Information System (INIS)

Yao Zhenyu; Hao Jiakun; Zhou Changshan; Shan Changqi; Yu Jinnan

2000-01-01

TiN + TiC + TiN and TiN + TiC + SiO 2 films were deposited on the surface of 316L austenitic stainless steel by means of physical vapor deposition (PVD). The thickness of the films was about 2-3 μm. The film is compact, oxidation-resistant, and has good adherence with the substrate below 500 deg. C. Tritium gas permeation of 316L with multiple films was examined, and it was found that the tritium permeability in 316L with a TiN + TiC + TiN film was 4-5 orders of magnitude lower, and in 316L with a TiN + TiC + SiO 2 film was 4-6 orders of magnitude lower than that in 316L with a Pd film at about 200-500 deg. C. At about 600 deg. C, the permeability of 316L with the multiple coating was 3-4 orders of magnitude lower than that in 316L with a Pd film. The result shows that the tritium permeation barrier is formed by multiple coating above 300 deg. C, and it is stable below 500 deg. C. However, the barrier is partly destroyed at about 600 deg. C because of oxidation; although this results in degradation of the barrier, it still plays a positive role. These films may be useful as coatings for the first wall, tritium blanket, and heat exchanger in fusion reactors for tritium permeation resistance

Transcorneal permeation of diclofenac as a function of temperature from film formulation in presence of triethanolamine and benzalkonium chloride.

Science.gov (United States)

Mohapatra, Rajaram; Senapati, Sibananda; Sahoo, Chinmaya; Mallick, Subrata

2014-11-01

The objective of this report was to evaluate the transcorneal permeation of diclofenac potassium (DCP) as a function of temperature from hydroxypropyl methylcellulose (HPMC) matrix film containing triethanolamine (TEM) as plasticizer and benzalkonium chloride (BKC) as preservative. Activation energy (Ea), enthalpy (ΔH), entropy (ΔS) and free energy (ΔG) of permeation, diffusion and partition were evaluated to understand the underlying mechanism of permeation. Permeation improved with the presence of both the plasticizer and preservative compared to preservative alone. Further, increased amount of TEM in the film increased drug transport across the cornea. Decreased Ea value of the film supported the fact. Rise of temperature from 26 to 30, 34 and 40 °C increased permeation in all the films. Ocular residence of the film in vivo in the rabbit revealed that the film swelled by pronounced lachrymal fluid uptake and traces of hydrogel remained still at the end of 6 h of application. Absence of characteristic exothermic peak of the drug in the thermogram of film formulations indicated the molecular dispersion of drug in polymer matrix. Scanning electron microscopy indicated that the drug crystal size decreased with increasing concentration of TEM in presence of BKC due to effective wetting of drug particles by the polymer. Copyright © 2014 Elsevier B.V. All rights reserved.